Sludge batch 9 (SB9) accepance evaluation: Radionuclide concentrations in tank 51 SB9 qualification sample prepared at SRNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.; Diprete, D.; Pareizs, J.

Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch 9 (SB9) for processing in the Defense Waste Processing Facility (DWPF). The SB9 material is currently in Tank 51 and has been washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF processing and is currently being processed as Sludge Batch 8 (SB8). The radionuclide concentrations were measured or estimated in the Tankmore » 51 SB9 Washed Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from a three liter sample of Tank 51 sludge slurry (HTF-51-15-81) taken on July 23, 2015. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. Under the direction of Savannah River Remediation (SRR) it was then adjusted per the Tank Farm washing strategy as of October 20, 2015. This final slurry now has a compositioniv expected to be similar to that of the slurry in Tank 51 after final preparations have been made for transfer of that slurry to Tank 40.« less

ENANTIOSELECTIVE MICROBIAL TRANSFORMATION OF THE PHENYLPYRAZOLE INSECTICIDE FIPRONIL IN ANOXIC SEDIMENTS

EPA Science Inventory

Fipronil, a chiral insecticide, was biotransformed initially to fipronil sulfide in anoxic sediment slurries following a short lag period. Sediment slurries characterized as either sulfidogenic or methanogenic transformed fipronil with half-lives of approximately 35 and 40 days, ...

DECHLORINATION ACTIVITY (CROSS-ACCLIMATION) OF FRESHWATER SEDIMENTS ADAPTED TO MONO- AND DI-CHLOROPHENOLS

EPA Science Inventory

The reductive dechlorination of chlorophenols (CPs) in sediment slurries (10% solids) adapted to dechlorinate mono- and di-CPs (DCP) was investigated to define the regiospecificity of the dechlorination reaction. nadapted sediment slurries amended with various ortho-substituted C...

30 CFR 77.216-1 - Water, sediment or slurry impoundments and impounding structures; identification.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Water, sediment or slurry impoundments and... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-1 Water, sediment or..., operating, or controlling the structure, shall be located on or immediately adjacent to each water, sediment...

30 CFR 77.216-1 - Water, sediment or slurry impoundments and impounding structures; identification.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Water, sediment or slurry impoundments and... AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Surface Installations § 77.216-1 Water, sediment or..., operating, or controlling the structure, shall be located on or immediately adjacent to each water, sediment...

The role of heterotrophic microorganism Galactomyces sp. Z3 in improving pig slurry bioleaching.

PubMed

Zhou, Jun; Zheng, Guanyu; Zhou, Lixiang; Liu, Fenwu; Zheng, Chaocheng; Cui, Chunhong

2013-01-01

The feasibility of removing heavy metals and eliminating pathogens from pig slurry through bioleaching involving the fungus Galactomyces sp. Z3 and two acidophilic thiobacillus (A. ferrooxidans LX5 and A. thiooxidans TS6) was investigated. It was found that the isolated pig slurry dissolved organic matter (DOM) degrader Z3 was identified as Galactomyces sp. Z3, which could grow well at pH 2.5-7 and degrade pig slurry DOM from 1973 to 942 mg/l within 48 h. During the successive multi-batch bioleaching systems, the co-inoculation of pig slurry degrader Galactomyces sp. Z3 and the two Acidithiobacillus species could improve pig slurry bioleaching efficiency compared to the single system without Galactomyces sp. Z3. The removal efficiency of Zn and Cu exceeded 94% and 85%, respectively. In addition, the elimination efficiencies of pathogens, including both total coliform and faecal coliform counts, exceeded 99% after bioleaching treatment. However, the counts of Galactomyces sp. Z3 decreased with the fall of pH and did not restore to the initial level during successive multi-batch bioleaching systems, and it is necessary to re-inoculate Galactomyces sp. Z3 cells into the bioleaching system to maintain its role in degrading pig slurry DOM. Therefore, a bioleaching technique involving both Galactomyces sp. Z3 and Acidithiobacillus species is an efficient method for removing heavy metals and eliminating pathogens from pig slurry.

Microbial physiology-based model of ethanol metabolism in subsurface sediments

NASA Astrophysics Data System (ADS)

Jin, Qusheng; Roden, Eric E.

2011-07-01

A biogeochemical reaction model was developed based on microbial physiology to simulate ethanol metabolism and its influence on the chemistry of anoxic subsurface environments. The model accounts for potential microbial metabolisms that degrade ethanol, including those that oxidize ethanol directly or syntrophically by reducing different electron acceptors. Out of the potential metabolisms, those that are active in the environment can be inferred by fitting the model to experimental observations. This approach was applied to a batch sediment slurry experiment that examined ethanol metabolism in uranium-contaminated aquifer sediments from Area 2 at the U.S. Department of Energy Field Research Center in Oak Ridge, TN. According to the simulation results, complete ethanol oxidation by denitrification, incomplete ethanol oxidation by ferric iron reduction, ethanol fermentation to acetate and H 2, hydrogenotrophic sulfate reduction, and acetoclastic methanogenesis: all contributed significantly to the degradation of ethanol in the aquifer sediments. The assemblage of the active metabolisms provides a frame work to explore how ethanol amendment impacts the chemistry of the environment, including the occurrence and levels of uranium. The results can also be applied to explore how diverse microbial metabolisms impact the progress and efficacy of bioremediation strategies.

Environmental process descriptors for TNT, TNT-related compounds and picric acid in marine sediment slurries.

PubMed

Yost, Sally L; Pennington, Judith C; Brannon, James M; Hayes, Charolett A

2007-08-01

Process descriptors were determined for picric acid, TNT, and the TNT-related compounds 2,4DNT, 2,6DNT, 2ADNT, 4ADNT, 2,4DANT, 2,6DANT, TNB and DNB in marine sediment slurries. Three marine sediments of various physical characteristics (particle size ranging from 15 to >90% fines and total organic carbon ranging from <0.10 to 3.60%) were kept in suspension with 20ppt saline water. Concentrations of TNT and its related compounds decreased immediately upon contact with the marine sediment slurries, with aqueous concentrations slowly declining throughout the remaining test period. Sediment-water partition coefficients could not be determined for these compounds since solution phase concentrations were unstable. Kinetic rates and half-lives were influenced by the sediment properties, with the finer grained, higher organic carbon sediment being the most reactive. Aqueous concentrations of picric acid were very stable, demonstrating little partitioning to the sediments. Degradation to picramic acid was minimal, exhibiting concentrations at or just above the detection limit.

Evaluation of zirconium as a permanent chemical modifier using synchrotron radiation and imaging techniques for lithium determination in sediment slurry samples by ET AAS.

PubMed

Flores, Araceli V; Pérez, Carlos A; Arruda, Marco A Z

2004-02-27

In the present paper, lithium was determined in river sediment using slurry sampling and electrothermal atomic absorption spectrometry (ET AAS) after L'vov platform coating with zirconium (as a permanent chemical modifier). The performance of this modifier and its distribution on the L'vov platform after different heating cycles were evaluated using synchrotron radiation X-ray fluorescence (SRXRF) and imaging scanning electron microscopy (SEM) techniques. The analytical conditions for lithium determination in river sediment slurries were also investigated and the best conditions were obtained employing 1300 and 2300 degrees C for pyrolysis and atomization temperatures, respectively. In addition, 100mg of sediment samples were prepared using 4.0moll(-1) HNO(3). The Zr-coating permitted lithium determination with good precision and accuracy after 480 heating cycles using the same platform for slurry samples. The sediment samples were collected from five different points of the Cachoeira river, São Paulo, Brazil. The detection and quantification limits were, respectively, 0.07 and 0.23mugl(-1).

Demethylation and cleavage of dimethylsulfoniopropionate in marine intertidal sediments

USGS Publications Warehouse

Visscher, P.T.; Kiene, R.P.; Taylor, B.F.

1994-01-01

Demethylation and cleavage of dimethylsulfoniopropionate (DMSP) was measured in three different types of,intertidal marine sediments: a cyanobacterial mat, a diatom-covered tidal flat and a carbonate sediment. Consumption rates of added DMSP were highest in cyanobacterial mat slurries (59 ?? mol DMSP l-1 slurry h-1) and lower in slurries from a diatom mat and a carbonate tidal sediment (24 and 9 ??mol DMSP l-1 h-1, respectively). Dimethyl sulfide (DMS) and 3-mercaptopropionate (MPA) were produced simultaneously during DMSP consumption, indicating that cleavage and demethylation occurred at the same time. Viable counts of DMSP-utilizing bacteria revealed a population of 2 x 107 cells cm-3 sediment (90% of these cleaved DMSP to DMS, 10% demethylated DMSP to MPA) in the cyanobacterial mat, 7 x 105 cells cm-3 in the diatom mat (23% cleavers, 77% demethylators), and 9 x 104 cells cm-3 (20% cleavers and 80% demethylators) in the carbonate sediment. In slurries of the diatom mat, the rate of MPA production from added 3-methiolpropionate (MMPA) was 50% of the rate of MPA formation from DMSP. The presence of a large population of demethylating bacteria and the production of MPA from DMSP suggest that the demethylation pathway, in addition to cleavage, contributes significantly to DMSP consumption in coastal sediments.

Sorption kinetics of TNT and RDX in anaerobic freshwater and marine sediments: Batch studies.

PubMed

Ariyarathna, Thivanka; Vlahos, Penny; Tobias, Craig; Smith, Richard

2016-01-01

Examination of the partitioning of explosives onto sediment in marine environments is critical to predict the toxicological impacts of worldwide explosive-contaminated sites adjacent to estuaries, wetlands, and the coastal ocean. Marine sediments have been identified as sites of enhanced munitions removal, yet most studies addressing these interactions focus on soils and freshwater sediments. The present study measured the kinetics of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) sorption onto 2 marine sediments of varying grain sizes (silt vs sand) and organic carbon (OC) content. Abiotic sediment sorption tests were performed at 23 °C, 15 °C, and 4 °C by spiking TNT and RDX solutions directly into anaerobic sediment slurries. Marine sediments showed significantly higher compound uptake rates (0.30-0.80 h(-1) ) than freshwater silt (0.0046-0.0065 h(-1) ) for both compounds, probably because of lower compound solubilities and a higher pH in marine systems. Equilibrium partition constants are on the same order of magnitude for marine silt (1.1-2.0 L kg(-1) sediment) and freshwater silt (1.4-3.1 L kg(-1) sediment) but lower for marine sand (0.72-0.92 L kg(-1) sediment). Total organic carbon content in marine sediments varied linearly with equilibrium partition constants for TNT and was moderately linear for RDX. Uptake rates and equilibrium constants of explosives are inversely correlated to temperature regardless of sediment type because of kinetic barriers associated with low temperatures. © 2015 SETAC.

PARTITIONING, DESORPTION, AND DECHLORINATION OF A PCB CONGENER IN SEDIMENT SLURRY SUPERNATANTS

EPA Science Inventory

Partitioning and desorption played specific roles in the dechlorination of 2-chlorobiphenyl (2-ClBP) in sediment slurry supernatants, which are suspensions of disssolved organic matter(DOM). In short-term experiments, the partition coefficient (K_p) was related to the a...

Results from tests of TFL Hydragard sampling loop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steimke, J.L.

When the Defense Waste Processing Facility (DWPF) is operational, processed radioactive sludge will be transferred in batches to the Slurry Mix Evaporator (SME), where glass frit will be added and the contents concentrated by boiling. Batches of the slurry mixture are transferred from the SME to the Melter Feed Tank (MFT). Hydragard{reg_sign} sampling systems are used on the SME and the MFT for collecting slurry samples in vials for chemical analysis. An accurate replica of the Hydragard sampling system was built and tested in the thermal Fluids Laboratory (TFL) to determine the hydragard accuracy. It was determined that the originalmore » Hydragard valve frequently drew a non-representative sample stream through the sample vial that ranged from frit enriched to frit depleted. The Hydragard valve was modified by moving the plunger and its seat backwards so that the outer surface of the plunger was flush with the inside diameter of the transfer line when the valve was open. The slurry flowing through the vial accurately represented the composition of the slurry in the reservoir for two types of slurries, different dilution factors, a range of transfer flows and a range of vial flows. It was then found that the 15 ml of slurry left in the vial when the Hydragard valve was closed, which is what will be analyzed at DWPF, had a lower ratio of frit to sludge as characterized by the lithium to iron ratio than the slurry flowing through it. The reason for these differences is not understood at this time but it is recommended that additional experimentation be performed with the TFL Hydragard loop to determine the cause.« less

Debris flow rheology: Experimental analysis of fine-grained slurries

USGS Publications Warehouse

Major, Jon J.; Pierson, Thomas C.

1992-01-01

The rheology of slurries consisting of ≤2-mm sediment from a natural debris flow deposit was measured using a wide-gap concentric-cylinder viscometer. The influence of sediment concentration and size and distribution of grains on the bulk rheological behavior of the slurries was evaluated at concentrations ranging from 0.44 to 0.66. The slurries exhibit diverse rheological behavior. At shear rates above 5 s−1 the behavior approaches that of a Bingham material; below 5 s−1, sand exerts more influence and slurry behavior deviates from the Bingham idealization. Sand grain interactions dominate the mechanical behavior when sand concentration exceeds 0.2; transient fluctuations in measured torque, time-dependent decay of torque, and hysteresis effects are observed. Grain rubbing, interlocking, and collision cause changes in packing density, particle distribution, grain orientation, and formation and destruction of grain clusters, which may explain the observed behavior. Yield strength and plastic viscosity exhibit order-of-magnitude variation when sediment concentration changes as little as 2–4%. Owing to these complexities, it is unlikely that debris flows can be characterized by a single rheological model.

Kinetics of biotransformation of chlorpyrifos in aqueous and soil slurry environments.

PubMed

Tiwari, Manoj K; Guha, Saumyen

2014-03-15

The attenuation of chlorpyrifos (CPF) by the enriched indigenous soil microorganism was studied in 15 d aerobic and 60 d anaerobic batch experiments in aqueous and soil slurry (1:3 w/w) media. At the end of the batch experiments, 2.78 ± 0.11 μM of CPF was degraded by 82% in aerobic and 66% in anaerobic aqueous environments, while 12.4 ± 0.5 μM of CPF was degraded by 48% in aerobic and 31% in anaerobic soil slurries. The reduced degradation in the soil slurries was due to the significantly (2-10 times) slower rate of degradation of soil phase CPF compared with its degradation rate in water. The pathways of degradation of CPF were identified, including a partial anaerobic degradation pathway that is constructed for the first time. The simulation of the various conversions in the degradation pathways using first order kinetics was used to analyze relative persistence of metabolites. The common metabolite 3,5,6-trichloro-2-pyridinol (TCP) accumulated (increased monotonically during the period of experiments) in aerobic soil slurry and in anaerobic aqueous as well as soil slurry systems but did not accumulate in aerobic aqueous system. The most toxic compound in the pathway, chlorpyrifos oxon (CPFO) was not detected in anaerobic environment. In aerobic environment, CPFO was short lived in aqueous medium, but accumulated slowly in the soils. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nitrous oxide production kinetics during nitrate reduction in river sediments.

PubMed

Laverman, Anniet M; Garnier, Josette A; Mounier, Emmanuelle M; Roose-Amsaleg, Céline L

2010-03-01

A significant amount of nitrogen entering river basins is denitrified in riparian zones. The aim of this study was to evaluate the influence of nitrate and carbon concentrations on the kinetic parameters of nitrate reduction as well as nitrous oxide emissions in river sediments in a tributary of the Marne (the Seine basin, France). In order to determine these rates, we used flow-through reactors (FTRs) and slurry incubations; flow-through reactors allow determination of rates on intact sediment slices under controlled conditions compared to sediment homogenization in the often used slurry technique. Maximum nitrate reduction rates (R(m)) ranged between 3.0 and 7.1microg Ng(-1)h(-1), and affinity constant (K(m)) ranged from 7.4 to 30.7mg N-NO(3)(-)L(-1). These values were higher in slurry incubations with an R(m) of 37.9microg Ng(-1)h(-1) and a K(m) of 104mg N-NO(3)(-)L(-1). Nitrous oxide production rates did not follow Michaelis-Menten kinetics, and we deduced a rate constant with an average of 0.7 and 5.4ng Ng(-1)h(-1) for FTR and slurry experiments respectively. The addition of carbon (as acetate) showed that carbon was not limiting nitrate reduction rates in these sediments. Similar rates were obtained for FTR and slurries with carbon addition, confirming the hypothesis that homogenization increases rates due to release of and increasing access to carbon in slurries. Nitrous oxide production rates in FTR with carbon additions were low and represented less than 0.01% of the nitrate reduction rates and were even negligible in slurries. Maximum nitrate reduction rates revealed seasonality with high potential rates in fall and winter and low rates in late spring and summer. Under optimal conditions (anoxia, non-limiting nitrate and carbon), nitrous oxide emission rates were low, but significant (0.01% of the nitrate reduction rates). Copyright 2009 Elsevier Ltd. All rights reserved.

Passive Sampling of Nonpolar Compounds in Sediments

DTIC Science & Technology

2010-12-02

Example 1: pore water sniffing PAHs/PCBs/HCB in harbor sediments ES&T 37: 4213-4220,2003 LDPE strips in sediment slurries and stagnant sediments...slurry stagnant ~160 g sediment (1-4% oc) ~120 mL water 0.5 g LDPE (30x2.5 cm) 50 d exposure chrysene msed Kd ≈1000 L ms Ksw ≈ 300 L ( or ) Koc from...silicone ! SPME! POG! LDPE ! Chemcatcher ! SPMD! POCIS! Mesco I 300 200 100 2 3 4 5 6 7 8 N ( n g ) log Kow Cw = 1 ng / L week 123456 Evolution of peak pattern

REUSABLE ADSORBENTS FOR DILUTE SOLUTIONS SEPARATION. 6. BATCH AND CONTINUOUS REACTORS FOR ADSORPTION AND DEGRADATION OF 1,2-DICHLOROBENZENE FROM DILUTE WASTEWATER STREAMS USING TITANIA AS A PHOTOCATALYST. (R828598C753)

EPA Science Inventory

Two types of external lamp reactors were investigated for the titania catalyzed photodegradation of 1,2-dichlorobenzene (DCB) from a dilute water stream. The first one was a batch mixed slurry reactor and the second one was a semi-batch reactor with continuous feed recycle wit...

Results of Hg speciation testing on DWPF SMECT-4, SMECT-6, and RCT-2 samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2016-02-04

The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team.i,ii The fifteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) samples from Sludge Receipt and Adjustment Tank (SRAT) Batch 738 and a Recycle Condensate Tank (RCT) sample from SRAT Batch 736. The DWPF sample designations for the three samples analyzed are provided in Table 1. The Batch 738 ‘Baseline’ SMECT sample was taken priormore » to Precipitate Reactor Feed Tank (PRFT) addition and concentration and therefore, precedes the SMECT-5 sample reported previously. iii The Batch 738 ‘End of SRAT Cycle’ SMECT sample was taken at the conclusion of SRAT operations for this batch (PRFT addition/concentration, acid additions, initial concentration, MCU addition, and steam stripping). Batch 738 experienced a sludge slurry carryover event, which introduced sludge solids to the SMECT that were particularly evident in the SMECT-5 sample, but less evident in the ‘End of SRAT Cycle’ SMECT-6 sample. The Batch 736 ‘After SME’ RCT sample was taken after completion of SMECT transfers at the end of the SME cycle.« less

Actual Waste Demonstration of the Nitric-Glycolic Flowsheet for Sludge Batch 9 Qualification

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. D. Newell; Pareizs, J. M.; Martino, C. J.

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) performs qualification testing to demonstrate that the sludge batch is processable. Testing performed by the Savannah River National Laboratory has shown glycolic acid to be effective in replacing the function of formic acid in the DWPF chemical process. The nitric-glycolic flowsheet reduces mercury, significantly lowers the catalytic generation of hydrogen and ammonia which could allow purge reduction in the Sludge Receipt and Adjustment Tank (SRAT), stabilizes the pH and chemistry in the SRAT and the Slurry Mix Evaporator (SME), allowsmore » for effective rheology adjustment, and is favorable with respect to melter flammability. In order to implement the new flowsheet, SRAT and SME cycles, designated SC-18, were performed using a Sludge Batch (SB) 9 slurry blended from SB8 Tank 40H and Tank 51H samples. The SRAT cycle involved adding nitric and glycolic acids to the sludge, refluxing to steam strip mercury, and dewatering to a targeted solids concentration. Data collected during the SRAT cycle included offgas analyses, process temperatures, heat transfer, and pH measurements. The SME cycle demonstrated the addition of glass frit and the replication of six canister decontamination additions. The demonstration concluded with dewatering to a targeted solids concentration. Data collected during the SME cycle included offgas analyses, process temperatures, heat transfer, and pH measurements. Slurry and condensate samples were collected for subsequent analysis« less

Vinegar production from post-distillation slurry deriving from rice shochu production with the addition of caproic acid-producing bacteria consortium and lactic acid bacterium.

PubMed

Yuan, Hua-Wei; Tan, Li; Chen, Hao; Sun, Zhao-Yong; Tang, Yue-Qin; Kida, Kenji

2017-12-01

To establish a zero emission process, the post-distillation slurry of a new type of rice shochu (NTRS) was used for the production of health promoting vinegar. Since the NTRS post-distillation slurry contained caproic acid and lactic acid, the effect of these two organic acids on acetic acid fermentation was first evaluated. Based on these results, Acetobacter aceti CICC 21684 was selected as a suitable strain for subsequent production of vinegar. At the laboratory scale, acetic acid fermentation of the NTRS post-distillation slurry in batch mode resulted in an acetic acid concentration of 41.9 g/L, with an initial ethanol concentration of 40 g/L, and the acetic acid concentration was improved to 44.5 g/L in fed-batch mode. Compared to the NTRS post-distillation slurry, the vinegar product had higher concentrations of free amino acids and inhibition of angiotensin I converting enzyme activity. By controlling the volumetric oxygen transfer coefficient to be similar to that of the laboratory scale production, 45 g/L of acetic acid was obtained at the pilot scale, using a 75-L fermentor with a working volume of 40 L, indicating that vinegar production can be successfully scaled up. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Sludge batch 9 follow-on actual-waste testing for the nitric-glycolic flowsheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martino, C. J.; Newell, J. D.; Crawford, C. L.

An actual-waste Sludge Batch 9 qualification run with the nitric-glycolic flowsheet (SC-18) was performed in FY16. In order to supplement the knowledge base for the nitric-glycolic flowsheet, additional testing was performed on the product slurries, condensates, and intermediate samples from run SC-18.

A microbial arsenic cycle in sediments of an acidic mine impoundment: Herman Pit, Clear Lake, California

USGS Publications Warehouse

Blum, Jodi S.; McCann, Shelley; Bennett, S.; Miller, Laurence G.; Stolz, J. R.; Stoneburner, B.; Saltikov, C.; Oremland, Ronald S.

2015-01-01

The involvement of prokaryotes in the redox reactions of arsenic occurring between its +5 [arsenate; As(V)] and +3 [arsenite; As(III)] oxidation states has been well established. Most research to date has focused upon circum-neutral pH environments (e.g., freshwater or estuarine sediments) or arsenic-rich “extreme” environments like hot springs and soda lakes. In contrast, relatively little work has been conducted in acidic environments. With this in mind we conducted experiments with sediments taken from the Herman Pit, an acid mine drainage impoundment of a former mercury (cinnabar) mine. Due to the large adsorptive capacity of the abundant Fe(III)-rich minerals, we were unable to initially detect in solution either As(V) or As(III) added to the aqueous phase of live sediment slurries or autoclaved controls, although the former consumed added electron donors (i.e., lactate, acetate, hydrogen), while the latter did not. This prompted us to conduct further experiments with diluted slurries using the live materials from the first incubation as inoculum. In these experiments we observed reduction of As(V) to As(III) under anoxic conditions and reduction rates were enhanced by addition of electron donors. We also observed oxidation of As(III) to As(V) in oxic slurries as well as in anoxic slurries amended with nitrate. We noted an acid-tolerant trend for sediment slurries in the cases of As(III) oxidation (aerobic and anaerobic) as well as for anaerobic As(V) reduction. These observations indicate the presence of a viable microbial arsenic redox cycle in the sediments of this extreme environment, a result reinforced by the successful amplification of arsenic functional genes (aioA, and arrA) from these materials.

Effects of imposed salinity gradients on dissimilatory arsenate reduction, sulfate reduction, and other microbial processes in sediments from two California soda lakes

USGS Publications Warehouse

Kulp, T.R.; Han, S.; Saltikov, C.W.; Lanoil, B.D.; Zargar, K.; Oremland, R.S.

2007-01-01

Salinity effects on microbial community structure and on potential rates of arsenate reduction, arsenite oxidation, sulfate reduction, denitrification, and methanogenesis were examined in sediment slurries from two California soda lakes. We conducted experiments with Mono Lake and Searles Lake sediments over a wide range of salt concentrations (25 to 346 g liter-1). With the exception of sulfate reduction, rates of all processes demonstrated an inverse relationship to total salinity. However, each of these processes persisted at low but detectable rates at salt saturation. Denaturing gradient gel electrophoresis analysis of partial 16S rRNA genes amplified from As(V) reduction slurries revealed that distinct microbial populations grew at low (25 to 50 g liter-1), intermediate (100 to 200 g liter-1), and high (>300 g liter-1) salinity. At intermediate and high salinities, a close relative of a cultivated As-respiring halophile was present. These results suggest that organisms adapted to more dilute conditions can remain viable at high salinity and rapidly repopulate the lake during periods of rising lake level. In contrast to As reduction, sulfate reduction in Mono Lake slurries was undetectable at salt saturation. Furthermore, sulfate reduction was excluded from Searles Lake sediments at any salinity despite the presence of abundant sulfate. Sulfate reduction occurred in Searles Lake sediment slurries only following inoculation with Mono Lake sediment, indicating the absence of sulfate-reducing flora. Experiments with borate-amended Mono Lake slurries suggest that the notably high (0.46 molal) concentration of borate in the Searles Lake brine was responsible for the exclusion of sulfate reducers from that ecosystem. Copyright ?? 2007, American Society for Microbiology. All Rights Reserved.

Removal of Suspended Solids in Anaerobically Digested Slurries of Livestock and Poultry Manure by Coagulation Using Different Dosages of Polyaluminum Chloride

NASA Astrophysics Data System (ADS)

Li, P.; Zhang, C. J.; Zhao, T. K.; Zhong, H.

2017-01-01

In this study, anaerobically digested slurries of livestock and poultry manure were pretreated by coagulation-sedimentation using an inorganic polymer coagulant, polyaluminum chloride (PAC). The effect of different PAC dosages on suspended solids (SS) removal and pH in the biogas slurries was assessed to provide reference values for reducing the organic load of biogas slurry in the coagulation-sedimentation process and explore the feasibility of reducing the difficulty in subsequent utilization or processing of biogas slurry. The results showed that for the pig slurry containing approximately 5000 mg/L SS, the removal rate of SS reached up to 81.6% with the coagulant dosage of 0.28 g/L PAC. For the chicken slurry containing approximately 2600 mg/L SS, the removal rate of SS was 30.2% with the coagulant dosage of 0.33 g/L PAC. The removal rate of SS in both slurries of livestock and poultry manure exhibited a downward trend with high PAC dosage. Therefore, there is a need to control the PAC dosage in practical use. The pH changed little in the two types of biogas slurries after treatment with different PAC dosages and both were in line with the standard values specified in the “Standards for Irrigation Water Quality”.

Effect of fermentation temperature on hydrogen production from cow waste slurry by using anaerobic microflora within the slurry.

PubMed

Yokoyama, Hiroshi; Waki, Miyoko; Moriya, Naoko; Yasuda, Tomoko; Tanaka, Yasuo; Haga, Kiyonori

2007-02-01

We examined hydrogen production from a dairy cow waste slurry (13.4 g of volatile solids per liter) by batch cultures in a temperature range from 37 to 85 degrees C, using microflora naturally present within the slurry. Without the addition of seed bacteria, hydrogen was produced by simply incubating the slurry, using the microflora within the slurry. Interestingly, two peaks of fermentation temperatures for hydrogen production from the slurry were observed at 60 and 75 degrees C (392 and 248 ml H2 per liter of slurry, respectively). After the termination of the hydrogen evolution, the microflora cultured at 60 degrees C displayed hydrogen-consuming activity, but hydrogen-consuming activity of the microflora cultured at 75 degrees C was not detected, at least for 24 days. At both 60 and 75 degrees C, the main by-product was acetate, and the optimum pH of the slurry for hydrogen production was around neutral. Bacteria related to hydrogen-producing moderate and extreme thermophiles, Clostridium thermocellum and Caldanaerobacter subterraneus, were detected in the slurries cultured at 60 and 75 degrees C, respectively, by denaturing gradient gel electrophoresis analyses, using the V3 region of 16S rDNA.

Method for separating liquid and solid products of liquefaction of coal or like carbonaceous materials

DOEpatents

Malek, John M.

1978-04-18

A method of improving the quality of slurry products taken from coal liquefaction reactors comprising subjecting the slurry to treatment with an alkaline compound such as caustic soda in the presence of steam in order to decompose the phenolic and acidic materials present in the slurry, and to also lower the slurry viscosity to allow separation of solid particles by sedimentation.

SAMPLING SYSTEM

DOEpatents

Hannaford, B.A.; Rosenberg, R.; Segaser, C.L.; Terry, C.L.

1961-01-17

An apparatus is given for the batch sampling of radioactive liquids such as slurries from a system by remote control, while providing shielding for protection of operating personnel from the harmful effects of radiation.

Microbiology: A microbial arsenic cycle in a salt-saturated, extreme environment

USGS Publications Warehouse

Oremland, R.S.; Kulp, T.R.; Blum, J.S.; Hoeft, S.E.; Baesman, S.; Miller, L.G.; Stolz, J.F.

2005-01-01

Searles Lake is a salt-saturated, alkaline brine unusually rich in the toxic element arsenic. Arsenic speciation changed from arsenate [As(V)] to arsenite [As(III)] with sediment depth. Incubated anoxic sediment slurries displayed dissimilatory As(V)-reductase activity that was markedly stimulated by H2 or sulfide, whereas aerobic slurries had rapid As(III)-oxidase activity. An anaerobic, extremely haloalkaliphilic bacterium was isolated from the sediment that grew via As(V) respiration, using either lactate or sulfide as its electron donor. Hence, a full biogeochemical cycle of arsenic occurs in Searles Lake, driven in part by inorganic electron donors.

Final Report - "Foaming and Antifoaming and Gas Entrainment in Radioactive Waste Pretreatment and Immobilization Processes"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wasan, Darsh T.

2007-10-09

The Savannah River Site (SRS) and Hanford site are in the process of stabilizing millions of gallons of radioactive waste slurries remaining from production of nuclear materials for the Department of Energy (DOE). The Defense Waste Processing Facility (DWPF) at SRS is currently vitrifying the waste in borosilicate glass, while the facilities at the Hanford site are in the construction phase. Both processes utilize slurry-fed joule-heated melters to vitrify the waste slurries. The DWPF has experienced difficulty during operations. The cause of the operational problems has been attributed to foaming, gas entrainment and the rheological properties of the process slurries.more » The rheological properties of the waste slurries limit the total solids content that can be processed by the remote equipment during the pretreatment and meter feed processes. Highly viscous material can lead to air entrainment during agitation and difficulties with pump operations. Excessive foaming in waste evaporators can cause carryover of radionuclides and non-radioactive waste to the condensate system. Experimental and theoretical investigations of the surface phenomena, suspension rheology and bubble generation of interactions that lead to foaming and air entrainment problems in the DOE High Level and Low Activity Radioactive Waste separation and immobilization processes were pursued under this project. The first major task accomplished in the grant proposal involved development of a theoretical model of the phenomenon of foaming in a three-phase gas-liquid-solid slurry system. This work was presented in a recently completed Ph.D. thesis (9). The second major task involved the investigation of the inter-particle interaction and microstructure formation in a model slurry by the batch sedimentation method. Both experiments and modeling studies were carried out. The results were presented in a recently completed Ph.D. thesis. The third task involved the use of laser confocal microscopy to study the effectiveness of three slurry rheology modifiers. An effective modifier was identified which resulted in lowering the yield stress of the waste simulant. Therefore, the results of this research have led to the basic understanding of the foaming/antifoaming mechanism in waste slurries as well as identification of a rheology modifier, which enhances the processing throughput, and accelerates the DOE mission. The objectives of this research effort were to develop a fundamental understanding of the physico-chemical mechanisms that produced foaming and air entrainment in the DOE High Level (HLW) and Low Activity (LAW) radioactive waste separation and immobilization processes, and to develop and test advanced antifoam/defoaming/rheology modifier agents. Antifoams/rheology modifiers developed from this research ere tested using non-radioactive simulants of the radioactive wastes obtained from Hanford and the Savannah River Site (SRS).« less

Pilot Study Report, Cape Canaveral Air Station, Florida. Permeable Reactive Treatment (PeRT) Wall Pilot Study. Revision 2

DTIC Science & Technology

1999-11-01

slurry was made from mixing iron, guar gum , an enzyme and borax. The guar gum was Hercules Supercol™ food grade fine (200-mesh size) powder . It was...Florida The guar gum was mixed with water in batches in a stirred open top tank to form 2 to 3% solutions. The guar gum solution was pumped first to a...holding tank, then into a truck-mounted batch mixing plant. A positive displacement pump controlled the feed rate of guar gum to the batch mixing plant

Bacterial ethane formation from reduced, ethylated sulfur compounds in anoxic sediments

USGS Publications Warehouse

Oremland, R.S.; Whiticar, Michael J.; Strohmaier, F.E.; Kiene, R.P.

1988-01-01

Trace levels of ethane were produced biologically in anoxic sediment slurries from five chemically different aquatic environments. Gases from these locations displayed biogenic characteristics, having 12C-enriched values of ??13CH4 (-62 to -86%.), ??13C2H6 (-35 to -55%.) and high ratios (720 to 140,000) of CH4 [C2H6 + C3H8]. Endogenous production of ethane by slurries was inhibited by autoclaving or by addition of the inhibitor of methanogenic bacteria, 2-bromoethanesulfonic acid (BES). Ethane formation was stimulated markedly by ethanethiol (ESH), and, to a lesser extent, by diethylsulfide (DES). Formation of methane and ethane in ESH- or DES-amended slurries was blocked by BES. Experiments showed that ethionine (or an analogous compound) could be a precursor of ESH. Ethylamine or ethanol additions to slurries caused only a minor stimulation of ethane formation. Similarly, propanethiol additions resulted in only a minor enhancement of propane formation. Cell suspensions of a methyltrophic methanogen produced traces of ethane when incubated in the presence of DES, although the organism did not grow on this compound. These results indicate that methanogenic bacteria produce ethane from the traces of ethylated sulfur compounds present in recent sediments. Preliminary estimates of stable carbon isotope fractionation associated with sediment methane formation from dimethylsulfide was about 40%., while ethane formation from DES and ESH was only 4. 6 and 6.5%., respectively. ?? 1988.

Effects of chlortetracycline amended feed on anaerobic sequencing batch reactor performance of swine manure digestion.

PubMed

Dreher, Teal M; Mott, Henry V; Lupo, Christopher D; Oswald, Aaron S; Clay, Sharon A; Stone, James J

2012-12-01

The effects of antimicrobial chlortetracycline (CTC) on the anaerobic digestion (AD) of swine manure slurry using anaerobic sequencing batch reactors (ASBRs) was investigated. Reactors were loaded with manure collected from pigs receiving CTC and no-antimicrobial amended diets at 2.5 g/L/d. The slurry was intermittently fed to four 9.5L lab-scale anaerobic sequencing batch reactors, two with no-antimicrobial manure, and two with CTC-amended manure, and four 28 day ASBR cycles were completed. The CTC concentration within the manure was 2 8 mg/L immediately after collection and 1.02 mg/L after dilution and 250 days of storage. CTC did not inhibit ASBR biogas production extent, however the volumetric composition of methane was significantly less (approximately 13% and 15% for cycles 1 and 2, respectively) than the no-antimicrobial through 56 d. CTC decreased soluble chemical oxygen demand and acetic acid utilization through 56 d, after which acclimation to CTC was apparent for the duration of the experiment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Reductive dechlorination of chlorobenzenes in surfactant-amended sediment slurries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Hoof, P.L.; Jafvert, C.T.

1996-11-01

Microbial anaerobic dechlorination of hexachlorobenzene (HCB) was examined in sediment slurries amended with two classes of nonionic surfactant, polyoxyethylene (POE) sorbitan fatty acid esters (Tweens) and POE alcohols (Brijs). The rationale for surfactant addition was to increase the bioavailability of highly sorbed organic pollutants to degrading microorganisms by enhancing their solubility. The solubility of HCB was initially enhanced via micellar partitioning; however, primary degradation of most surfactants occurred within 10 d. Dechlorination activity was significantly reduced at POE alcohol concentrations above the critical micelle concentration (cmc), with or without the occurrence of surfactant degradation. Tween 80 decreased HCB dechlorination atmore » concentrations significantly above the cmc. At concentrations closer to the cmc, Tween 80 increased dechlorination rate constants four- to fivefold in acclimated slurries. Additions of Tween 80 at or below the cmc stimulated dechlorination activity in unacclimated slurries that exhibited very little activity in unamended controls. An average of 89% of HCB was dechlorinated after 90 d, compared to 20% in unamended sediments. No effect was observed for POE alcohols at these sub-cmc levels. The lack of a stimulated response for the POE alcohols suggests that Tween 80 may not be acting simply as a source of carbon or energy.« less

Transformations of TNT and related aminotoluenes in groundwater aquifer slurries under different electron-accepting conditions

USGS Publications Warehouse

Krumholz, L.R.; Li, J.; Clarkson, W.W.; Wilber, G.G.; Suflita, J.M.

1997-01-01

The transport and fate of pollutants is often governed by both their tendency to sorb as well as their susceptibility to biodegradation. We have evaluated these parameters for 2,4,6-trinitrotoluene (TNT) and several biodegradation products. Slurries of aquifer sediment and groundwater depleted TNT at rates of 27, 7.7 and 5.9 μM day−1 under methanogenic, sulfate-reducing and nitrate-reducing conditions, respectively. Abiotic losses of TNT were determined in autoclaved controls. Abiotic TNT loss and subsequent transformation of the products was also observed. These transformations were especially important during the first step in the reduction of TNT. Subsequent abiotic reactions could account for all of the transformations observed in bottles which were initially nitrate-reducing. Other controls removed TNT reduction products at much slower rates than slurries containing live organisms. 2-Amino-4,6-dinitrotoluene was produced in all slurries but disappeared in methanogenic and in sulfate-reducing slurries within several weeks. This compound was converted to 2,4-diamino-6-nitrotoluene in all slurries with subsequent removal of the latter from methanogenic and sulfate-reducing slurries, while it persisted in autoclaved controls and in the nitrate-reducing slurries. Aquifer slurries incubated with either 2,4- or 2,6-diaminotoluene showed losses of these compounds relative to autoclaved controls under nitrate-reducing conditions but not under sulfate-reducing or methanogenic conditions. These latter compounds are important as reduced intermediates in the biodegradation of dinitrotoluenes and as industrial chemicals. In experiments to examine sorption, exposure to landfill sediment resulted in losses of approximately 15% of diaminotoluene isomers and 25% of aminodinitrotoluene isomers from initial solution concentrations within 24 h. Isotherms confirmed that the diaminotoluenes were least strongly sorbed and the amino-dinitrotoluenes most strongly sorbed to this sediment, while TNT sorption capacity was intermediate. In our studies, 2,4,6-triaminotoluene sorption capacity was indeterminate due to its chemical instability. Coupled with biodegradation information, isotherms help describe the likelihood of contaminant removal, persistence, and movement at impacted sites.

Cultivation of microalgae Chlorella zofingiensis on municipal wastewater and biogas slurry towards bioenergy.

PubMed

Zhou, Weizheng; Wang, Zhongming; Xu, Jingliang; Ma, Longlong

2018-05-22

The high cost of large-scale cultivation of microalgae has limited their industrial application. This study investigated the potential use of mixed biogas slurry and municipal wastewater to cultivate microalgae. Pig biogas slurry as the sole nutrient supplement, was assessed for the cultivation of Chlorella zofingiensis in municipal wastewater. Batch culture of various ratios of pig biogas slurry and municipal wastewater were compared. The characteristics of algal growth and lipid production were analyzed, and the removal rates of nitrogen and phosphate were examined. Results indicate that 8% pig bio-gas slurry in municipal wastewater, had a significant effect on microalgal growth. C. zofingiensis, with 2.5 g L -1 biomass, 93% total nitrogen and 90% total phosphorus removal. Lipid content was improved by 8% compared to BG11 medium. These findings show that mixing pig biogas slurry and municipal wastewater, without additional nutrition sources, allows efficient cultivation of C. zofingiensis. This is of high research and industrial significance, allowing cultivation of C. zofingiensis in mixed waste culture solution without additional nutrition sources. Copyright © 2018. Published by Elsevier B.V.

Analyzing turbidity, suspended-sediment concentration, and particle-size distribution resulting from a debris flow on Mount Jefferson, Oregon, November 2006

USGS Publications Warehouse

Uhrich, Mark A.

2010-01-01

A debris flow and sediment torrent occurred on the flanks of Mt Jefferson in Oregon on November 6, 2006, inundating 150 acres of forest. The massive debris flow was triggered by a rock and snow avalanche from the Milk Creek glaciers and snowfields during the early onset of an intense storm originating near the Hawaiian Islands. The debris flow consisted of a heavy conglomerate of large boulders, cobbles, and coarse-grained sediment that was deposited at depths of up to 15 ft and within 3 mi of the glaciers, and a viscous slurry that deposited finer-grained sediments at depths of 0.5 to 3 ft. The muddy slurry coated standing trees within the lower reaches of Milk Creek as it moved downslope.

Sustainable management and utilisation of concrete slurry waste: A case study in Hong Kong.

PubMed

Hossain, Md Uzzal; Xuan, Dongxing; Poon, Chi Sun

2017-03-01

With the promotion of environmental protection in the construction industry, the mission to achieve more sustainable use of resources during the production process of concrete is also becoming important. This study was conducted to assess the environmental sustainability of concrete slurry waste (CSW) management by life cycle assessment (LCA) techniques, with the aim of identifying a resource-efficient solution for utilisation of CSW in the production of partition wall blocks. CSW is the dewatered solid residues deposited in the sedimentation tank after washing out over-ordered/rejected fresh concrete and concrete trucks in concrete batching plants. The reuse of CSW as recycled aggregates or a cementitious binder for producing partition wall blocks, and the life cycle environmental impact of the blocks were assessed and compared with the conventional one designed with natural materials. The LCA results showed that the partition wall blocks prepared with fresh CSW and recycled concrete aggregates achieved higher sustainability as it consumed 59% lower energy, emitted 66% lower greenhouse gases, and produced lesser amount of other environmental impacts than that of the conventional one. When the mineral carbonation technology was further adopted for blocks curing using CO 2 , the global warming potential of the corresponding blocks production process was negligible, and hence the carbonated blocks may be considered as carbon neutral eco-product. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of organic matter, nutrients, and cyclodextrin on microbial and chemical herbicide and degradate dissipation in subsurface sediment slurries.

PubMed

Kerminen, Kaisa; Le Moël, Romain; Harju, Vilhelmiina; Kontro, Merja H

2018-03-15

Pesticides leaching from soil to surface and groundwater are a global threat for drinking water safety, as no cleaning methods occur for groundwater environment. We examined whether peat, compost-peat-sand (CPS) mixture, NH 4 NO 3 , NH 4 NO 3 with sodium citrate (Na-citrate), and the surfactant methyl-β-cyclodextrin additions enhance atrazine, simazine, hexazinone, dichlobenil, and the degradate 2,6-dichlorobenzamide (BAM) dissipations in sediment slurries under aerobic and anaerobic conditions, with sterilized controls. The vadose zone sediment cores were drilled from a depth of 11.3-14.6m in an herbicide-contaminated groundwater area. The peat and CPS enhanced chemical atrazine and simazine dissipation, and the peat enhanced chemical hexazinone dissipation, all oxygen-independently. Dichlobenil dissipated under all conditions, while BAM dissipation was fairly slow and half-lives could not be calculated. The chemical dissipation rates could be associated with the chemical structures and properties of the herbicides, and additive compositions, not with pH. Microbial atrazine degradation was only observed in the Pseudomonas sp. ADP amended slurries, although the sediment slurries were known to contain atrazine-degrading microorganisms. The bioavailability of atrazine in the water phase seemed to be limited, which could be due to complex formation with organic and inorganic colloids. Atrazine degradation by indigenous microbes could not be stimulated by the surfactant methyl-β-cyclodextrin, or by the additives NH 4 NO 3 and NH 4 NO 3 with Na-citrate, although the nitrogen additives increased microbial growth. Copyright © 2017 Elsevier B.V. All rights reserved.

ANAEROBIC BIODEGRADATION OF 2,4-DICHLOROPHENOL IN FRESHWATER LAKE SEDIMENTS AT DIFFERENT TEMPERATURES

EPA Science Inventory

Anaerobic degradation of 2,4-dichlorophenol (2,4-DCP) between 5 and 72C was investigated. naerobic sediment slurries prepared from local freshwater sediments were partitioned into anaerobic tubes or serum vials, which then were incubated separately at the various temperatures. ed...

Influence of coal slurry particle composition on pipeline hydraulic transportation behavior

NASA Astrophysics Data System (ADS)

Li-an, Zhao; Ronghuan, Cai; Tieli, Wang

2018-02-01

Acting as a new type of energy transportation mode, the coal pipeline hydraulic transmission can reduce the energy transportation cost and the fly ash pollution of the conventional coal transportation. In this study, the effect of average velocity, particle size and pumping time on particle composition of coal particles during hydraulic conveying was investigated by ring tube test. Meanwhile, the effects of particle composition change on slurry viscosity, transmission resistance and critical sedimentation velocity were studied based on the experimental data. The experimental and theoretical analysis indicate that the alter of slurry particle composition can lead to the change of viscosity, resistance and critical velocity of slurry. Moreover, based on the previous studies, the critical velocity calculation model of coal slurry is proposed.

Impact of chemical amendment of dairy cattle slurry on phosphorus, suspended sediment and metal loss to runoff from a grassland soil.

PubMed

Brennan, R B; Fenton, O; Grant, J; Healy, M G

2011-11-01

Emerging remediation technologies such as chemical amendment of dairy cattle slurry have the potential to reduce phosphorus (P) solubility and consequently reduce P losses arising from land application of dairy cattle slurry. The aim of this study was to determine the effectiveness of chemical amendment of slurry to reduce incidental losses of P and suspended sediment (SS) from grassland following application of dairy cattle slurry and to examine the effect of amendments on metal concentrations in runoff water. Intact grassed-soil samples were placed in two laboratory runoff boxes, each 200-cm-long by 22.5-cm-wide by 5-cm-deep, before being amended with dairy cattle slurry (the study control) and slurry amended with either: (i) alum, comprising 8% aluminium oxide (Al(2)O(3)) (1.11:1 aluminium (Al):total phosphorus (TP) of slurry) (ii) poly-aluminium chloride hydroxide (PAC) comprising 10% Al(2)O(3) (0.93:1 Al:TP) (iii) analytical grade ferric chloride (FeCl(2)) (2:1 Fe:TP), (iv) and lime (Ca(OH)(2)) (10:1 Ca:TP). When compared with the study control, PAC was the most effective amendment, reducing dissolved reactive phosphorus (DRP) by up to 86% while alum was most effective in reducing SS (88%), TP (94%), particulate phosphorus (PP) (95%), total dissolved phosphorus (TDP) (81%), and dissolved unreactive phosphorus (DUP) (86%). Chemical amendment of slurry did not appear to significantly increase losses of Al and Fe compared to the study control, while all amendments increased Ca loss compared to control and grass-only treatment. While chemical amendments were effective, the reductions in incidental P losses observed in this study were similar to those observed in other studies where the time from slurry application to the first rainfall event was increased. Timing of slurry application may therefore be a much more feasible way to reduce incidental P losses. Future work must examine the long-term effects of amendments on P loss to runoff and not only incidental losses. Copyright © 2011 Elsevier B.V. All rights reserved.

Slurry sampling high-resolution continuum source electrothermal atomic absorption spectrometry for direct beryllium determination in soil and sediment samples after elimination of SiO interference by least-squares background correction.

PubMed

Husáková, Lenka; Urbanová, Iva; Šafránková, Michaela; Šídová, Tereza

2017-12-01

In this work a simple, efficient, and environmentally-friendly method is proposed for determination of Be in soil and sediment samples employing slurry sampling and high-resolution continuum source electrothermal atomic absorption spectrometry (HR-CS-ETAAS). The spectral effects originating from SiO species were identified and successfully corrected by means of a mathematical correction algorithm. Fractional factorial design has been employed to assess the parameters affecting the analytical results and especially to help in the development of the slurry preparation and optimization of measuring conditions. The effects of seven analytical variables including particle size, concentration of glycerol and HNO 3 for stabilization and analyte extraction, respectively, the effect of ultrasonic agitation for slurry homogenization, concentration of chemical modifier, pyrolysis and atomization temperature were investigated by a 2 7-3 replicate (n = 3) design. Using the optimized experimental conditions, the proposed method allowed the determination of Be with a detection limit being 0.016mgkg -1 and characteristic mass 1.3pg. Optimum results were obtained after preparing the slurries by weighing 100mg of a sample with particle size < 54µm and adding 25mL of 20% w/w glycerol. The use of 1μg Rh and 50μg citric acid was found satisfactory for the analyte stabilization. Accurate data were obtained with the use of matrix-free calibration. The accuracy of the method was confirmed by analysis of two certified reference materials (NIST SRM 2702 Inorganics in Marine Sediment and IGI BIL-1 Baikal Bottom Silt) and by comparison of the results obtained for ten real samples by slurry sampling with those determined after microwave-assisted extraction by inductively coupled plasma time of flight mass spectrometry (TOF-ICP-MS). The reported method has a precision better than 7%. Copyright © 2017 Elsevier B.V. All rights reserved.

The effect of operating conditions on the performance of soil slurry-SBRs.

PubMed

Cassidy, D P; Irvine, R L

2001-01-01

Biological treatment of a silty clay loam with aged diesel fuel contamination was conducted in 8 L Soil Slurry-Sequencing Batch Reactors (SS-SBRs). The purpose was to monitor slurry conditions and evaluate reactor performance for varying solids concentration (5%, 25%, 40%, 50%), mixing speed (300 rpm, 700 rpm, 1200 rpm), retention time (8 d, 10 d, 20 d), and volume replaced per cycle (10%, 50%, 90%). Diesel fuel was measured in slurry and in filtered aqueous samples. Oxygen uptake rate (OUR) was monitored. Aggregate size was measured with sieve analyses. Biosurfactant production was quantified with surface tension measurements. Increasing solids concentration and decreasing mixing speed resulted in increased aggregate size, which in turn increased effluent diesel fuel concentrations. Diesel fuel removal was unaffected by retention time and volume replaced per cycle. Biosurfactant production occurred with all operating strategies. Foam thickness was related to surfactant concentration and mixing speed. OUR, surfactant concentration, and foam thickness increased with increasing diesel fuel added per cycle.

Controls on resilience and stability in a sediment-subsidized salt marsh.

PubMed

Stagg, Camille L; Mendelssohn, Irving A

2011-07-01

Although the concept of self-design is frequently employed in restoration, reestablishment of primary physical drivers does not always result in a restored ecosystem having the desired ecological functions that support system resilience and stability. We investigated the use of a primary environmental driver in coastal salt marshes, sediment availability, as a means of promoting the resilience and stability of submerging deltaic salt marshes, which are rapidly subsiding due to natural and human-induced processes. We conducted a disturbance-recovery experiment across a gradient of sediment slurry addition to assess the roles of sediment elevation and soil physico-chemical characteristics on vegetation resilience and stability in two restored salt marshes of differing age (a 15-year-old site and a 5-year-old site). Salt marshes that received moderate intensities of sediment slurry addition with elevations at the mid to high intertidal zone (2-11 cm above local mean sea level; MSL) were more resilient than natural marshes. The primary regulator of enhanced resilience and stability in the restored marshes was the alleviation of flooding stress observed in the natural, unsubsidized marsh. However, stability reached a sediment addition threshold, at an elevation of 11 cm above MSL, with decreasing stability in marshes above this elevation. Declines in resilience and stability above the sediment addition threshold were principally influenced by relatively dry conditions that resulted from insufficient and infrequent flooding at high elevations. Although the older restored marsh has subsided over time, areas receiving too much sediment still had limited stability 15 years later, emphasizing the importance of applying the appropriate amount of sediment to the marsh. In contrast, treated marshes with elevations 2-11 cm above MSL were still more resilient than the natural marsh 15 years after restoration, illustrating that when performed correctly, sediment slurry addition can be a sustainable restoration technique.

Resource-limited heterotrophic prokaryote production and its potential environmental impact associated with Mn nodule exploitation in the northeast equatorial pacific.

PubMed

Hyun, Jung-Ho

2006-08-01

Shipboard enrichment incubation experiments were performed to elucidate the limiting resources for heterotrophic prokaryotic production and to discuss the potential impact of bottom water and sediment discharges in relation to manganese (Mn) nodule exploitation on the heterotrophic prokaryotes in the oligotrophic northeast equatorial Pacific. Compared to an unamended control, the production of heterotrophic prokaryotes increased 25-fold in water samples supplemented with amino acids (i.e., organic carbon plus nitrogen), whereas the production increased five and two times, respectively, in samples supplemented with either glucose or ammonium alone. These results indicate that heterotrophic prokaryote production in the northeast equatorial Pacific was co-limited by the availability of dissolved organic carbon and inorganic nitrogen. In samples from the nutrient-depleted surface mixed layer (10-m depth), the addition of a slurry of bottom water and sediment doubled heterotrophic prokaryote production compared to an unamended control, whereas sonicating the slurry prior to addition quadrupled the production rate. However, little difference was observed between an unamended control and slurry-amended samples in the subsurface chlorophyll a (Chl a) maximum (SCM) layer. Thus, the impact of slurry discharge is more significant at the nutrient-depleted surface mixed layer than at the high-nutrient SCM layer. The greatly enhanced prokaryote production resulting from the addition of sonicated slurry further suggests that dissociated organic carbon may directly stimulate heterotrophic prokaryote production in the surface mixed layer. Overall, the results suggest that the surface discharge of bottom water and sediments during manganese nodule exploitation could have a significant environmental impact on the production of heterotrophic prokaryotes that are currently resource limited.

Impact of electron acceptor availability on the anaerobic oxidation of methane in coastal freshwater and brackish wetland sediments

NASA Astrophysics Data System (ADS)

Segarra, Katherine E. A.; Comerford, Christopher; Slaughter, Julia; Joye, Samantha B.

2013-08-01

Methane, a powerful greenhouse gas, is both produced and consumed in anoxic coastal sediments via microbial processes. Although the anaerobic oxidation of methane (AOM) is almost certainly an important process in coastal freshwater and salt marsh sediments, the factors that control the rates and pathways of AOM in these habitats are poorly understood. Here, we present the first direct measurements of AOM activity in freshwater (0 PSU) and brackish (25 PSU) wetland sediments. Despite disparate sulfate concentrations, both environments supported substantial rates of AOM. Higher sulfate reduction (SR) rates were measured in the freshwater site and SR at both sites was of sufficient magnitude to support the observed AOM activity. Laboratory incubations of freshwater and brackish tidal, wetland sediments amended with either nothing [control], sulfate, nitrate, manganese oxide (birnessite) or iron oxide (ferrihydrite) and supplied with a methane headspace were used to evaluate the impact(s) of electron acceptor availability on potential AOM rates. Maximum AOM rates in brackish slurries occurred in the sulfate amendments. In contrast, addition of sulfate and several possible electron acceptors to the freshwater slurries decreased AOM rates relative to the control. High ratios of AOM activity relative to SR activity in the nitrate, birnessite, and ferrihydrite treatments of both the brackish and freshwater slurries provided evidence of AOM decoupled from SR. This study demonstrates that both freshwater and brackish coastal wetland sediments support considerable rates of anaerobic methanotrophy and provides evidence for sulfate-independent AOM that may be coupled to nitrate, iron, or manganese reduction in both environments.

Phylogenetic and enzymatic diversity of deep subseafloor aerobic microorganisms in organics- and methane-rich sediments off Shimokita Peninsula.

PubMed

Kobayashi, Tohru; Koide, Osamu; Mori, Kozue; Shimamura, Shigeru; Matsuura, Takae; Miura, Takeshi; Takaki, Yoshihiro; Morono, Yuki; Nunoura, Takuro; Imachi, Hiroyuki; Inagaki, Fumio; Takai, Ken; Horikoshi, Koki

2008-07-01

"A meta-enzyme approach" is proposed as an ecological enzymatic method to explore the potential functions of microbial communities in extreme environments such as the deep marine subsurface. We evaluated a variety of extra-cellular enzyme activities of sediment slurries and isolates from a deep subseafloor sediment core. Using the new deep-sea drilling vessel "Chikyu", we obtained 365 m of core sediments that contained approximately 2% organic matter and considerable amounts of methane from offshore the Shimokita Peninsula in Japan at a water depth of 1,180 m. In the extra-sediment fraction of the slurry samples, phosphatase, esterase, and catalase activities were detected consistently throughout the core sediments down to the deepest slurry sample from 342.5 m below seafloor (mbsf). Detectable enzyme activities predicted the existence of a sizable population of viable aerobic microorganisms even in deep subseafloor habitats. The subsequent quantitative cultivation using solid media represented remarkably high numbers of aerobic, heterotrophic microbial populations (e.g., maximally 4.4x10(7) cells cm(-3) at 342.5 mbsf). Analysis of 16S rRNA gene sequences revealed that the predominant cultivated microbial components were affiliated with the genera Bacillus, Shewanella, Pseudoalteromonas, Halomonas, Pseudomonas, Paracoccus, Rhodococcus, Microbacterium, and Flexibacteracea. Many of the predominant and scarce isolates produced a variety of extra-cellular enzymes such as proteases, amylases, lipases, chitinases, phosphatases, and deoxyribonucleases. Our results indicate that microbes in the deep subseafloor environment off Shimokita are metabolically active and that the cultivable populations may have a great potential in biotechnology.

COMPARISONS OF COARSE AND FINE VERSIONS OF TWO CARBONS FOR REDUCING THE BIOAVAILABILITIES OF SEDIMENT-BOUND HYDROPHOBIC ORGANIC CONTAMINANTS

EPA Science Inventory

Course (whole) and finely ground Ambersorb 1500 and course and fine coconut charcoal were compared as to their efficiencies in scavenging organic contaminants desorbed from sediment. Aqueous slurries of a test sediment spiked (1 ppm) with p,p'-(DDE), 2,2',5,5'-tetrachlorobiphenyl...

An experimental investigation of hyperpycnal flow

NASA Astrophysics Data System (ADS)

Boland, T. M.; Hsu, T.

2010-12-01

The understanding of river-borne sediment dispersal in the coastal environment is an important problem in coastal/estuarine research. While it remains difficult to quantify how river discharges sediment into the coastal environment, it has been found that there are many qualitative similarities among rivers around the world. Amid these similarities is the formation of freshwater sediment-laden plumes, positively and negatively buoyant, that extend from river mouths into the ocean. Research has been conducted to help understand how sediment is deposited from these plumes for different idealized coastal settings. A series of laboratory experiments were performed to study sediment-laden freshwater plumes within a saltwater tank. Both hyperpycnal and hypopycnal plumes were created by pumping sediment-laden freshwater with a given sediment concentration into a saltwater tank with a constant salinity of 12.5 ppt. Salinity was measured prior to each experiment with the Mannix TDS503 Pocket TDS Meter. Kaolin clay with a primary particle size of D50 = 0.2 μm was used. Freshwater and sediment were mixed in a 50 gallon barrel with fluorescent dye, which improves the visual distinction between the slurry and the ambient water. The saltwater tank is a 3 meter long, 0.15 meter wide, and 0.5 meter deep flume with an adjustable slope (four different slopes, 50, 30, 20, 10 degrees, were investigated) where the slurry enters. Four different sediment concentrations were used with each slope: 15 g/l, 20 g/l, 25 g/l, and 30 g/l, creating a total of sixteen trials for analysis. A Sony SR11 camcorder was used to capture video of the plumes as they move across the tank. Image analysis was performed using a Matlab code to measure parameters in order to describe the plumes. These include velocity, thickness, liftoff distance, and separation distance. Resultant plumes are found to depend on the initial sediment concentration of the slurry as well as the slope used at the entrance of the tank. . Observations were divided into three regimes: fully buoyant plumes (hypopycnal plume), submerged plumes (hyperpycnal plume) that separated from the slurry discharge, and fully submerged plumes that did not separate. Measured data is used to quantify the lift-off distance as a function of inlet condition and occurrence of divergent plume. For several high concentration trials, the occurrence of convective fingers is observed after plume lift-off. A hyperpycnal plume separtes from the discharge to move along the bottom of the tank, while a hypopycnal plume develops and moves along the surface.

Degradation of phthalate esters and acetaminophen in river sediments using the electrokinetic process integrated with a novel Fenton-like process catalyzed by nanoscale schwertmannite.

PubMed

Yang, Gordon C C; Huang, Sheng-Chih; Wang, Chih-Lung; Jen, Yu-Sheng

2016-09-01

The main objective of this study was to develop and establish an in situ remediation technology coupling nano-schwertmannite/H2O2 process and electrokinetic (EK) process for the removal of phthalates (PAEs) and acetaminophen in river sediments. Test results are given as follows: (1) injection of nano-schwertmannite slurry and H2O2 (collectively, "novel oxidant") into the anode reservoir would yield ·OH radicals that then will be diffused into the sediment compartment and further transported by the electroosmotic flow and/or electrophoresis from the anode end toward the cathode to degrade PAEs and pharmaceuticals in the sediment if any; (2) an electric potential gradient of 1.5 V cm(-1) would help the removal of PAEs and acetaminophen in the blank test, which no "novel oxidants" was added to the remediation system; (3) the practice of electrode polarity reversal would maintain neutral pH for sediment after remediation; (4) injection of equally divided dose of 10 mL novel oxidant into the anode reservoir and four injection ports on the top of sediment chamber would further enhance the removal efficiency; and (5) an extension of treatment time from 14 d to 28 d is beneficial to the removal efficiency as expected. In comparison, the remediation performance obtained by the EK-assisted nano-SHM/H2O2 oxidation process is superior to that of the batch degradation test, but is comparable with other EK integrated technologies for the treatment of same contaminants. Thus, it is expected that the EK-assisted nano-SHM/H2O2 oxidation process is a viable technology for the removal of phthalate esters and pharmaceuticals from river sediments in large-scale operations. Copyright © 2016 Elsevier Ltd. All rights reserved.

SLUDGE WASHING AND DEMONSTRATION OF THE DWPF FLOWSHEET IN THE SRNL SHIELDED CELLS FOR SLUDGE BATCH 7A QUALIFICATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Billings, A.; Click, D.

2011-07-08

Waste Solidification Engineering (WSE) has requested that characterization and a radioactive demonstration of the next batch of sludge slurry (Sludge Batch 7a*) be completed in the Shielded Cells Facility of the Savannah River National Laboratory (SRNL) via a Technical Task Request (TTR). This characterization and demonstration, or sludge batch qualification process, is required prior to transfer of the sludge from Tank 51 to the Defense Waste Processing Facility (DWPF) feed tank (Tank 40). The current WSE practice is to prepare sludge batches in Tank 51 by transferring sludge from other tanks. Discharges of nuclear materials from H Canyon are oftenmore » added to Tank 51 during sludge batch preparation. The sludge is washed and transferred to Tank 40, the current DWPF feed tank. Prior to transfer of Tank 51 to Tank 40, SRNL simulates the Tank Farm and DWPF processes with a Tank 51 sample (referred to as the qualification sample). Sludge Batch 7a (SB7a) is composed of portions of Tanks 4, 7, and 12; the Sludge Batch 6 heel in Tank 51; and a plutonium stream from H Canyon. SRNL received the Tank 51 qualification sample (sample ID HTF-51-10-125) following sludge additions to Tank 51. This report documents: (1) The washing (addition of water to dilute the sludge supernate) and concentration (decanting of supernate) of the SB7a - Tank 51 qualification sample to adjust sodium content and weight percent insoluble solids to Tank Farm projections. (2) The performance of a DWPF Chemical Process Cell (CPC) simulation using the washed Tank 51 sample. The simulation included a Sludge Receipt and Adjustment Tank (SRAT) cycle, where acid was added to the sludge to destroy nitrite and reduce mercury, and a Slurry Mix Evaporator (SME) cycle, where glass frit was added to the sludge in preparation for vitrification. The SME cycle also included replication of five canister decontamination additions and concentrations. Processing parameters were based on work with a non-radioactive simulant. (3) Vitrification of a portion of the SME product and characterization and durability testing (as measured by the Product Consistency Test (PCT)) of the resulting glass. (4) Rheology measurements of the initial slurry samples and samples after each phase of CPC processing. This program was controlled by a Task Technical and Quality Assurance Plan (TTQAP), and analyses were guided by an Analytical Study Plan. This work is Technical Baseline Research and Development (R&D) for the DWPF. It should be noted that much of the data in this document has been published in interoffice memoranda. The intent of this technical report is bring all of the SB7a related data together in a single permanent record and to discuss the overall aspects of SB7a processing.« less

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

DOEpatents

Golden, Jeffry

2007-02-13

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

DOEpatents

Mincher, Bruce J.; Curry, Randy Dale; Clevenger, Thomas E.; Golden, Jeffry

2003-05-27

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Process for the solvent extraction for the radiolysis and dehalogenation of halogenated organic compounds in soils, sludges, sediments and slurries

DOEpatents

Mincher, Bruce J.; Curry, Randy Dale; Clevenger, Thomas E.; Golden, Jeffry

2000-01-01

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacting a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Anaerobic oxidation of acetylene by estuarine sediments and enrichment cultures

USGS Publications Warehouse

Culbertson, Charles W.; Zehnder, Alexander J. B.; Oremland, Ronald S.

1981-01-01

Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloramphenicol, air, and autoclaving. Addition of 14C2H2 to slurries resulted in the formation of 14CO2 and the transient appearance of 14C-soluble intermediates, of which acetate was a major component. Acetylene oxidation stimulated sulfate reduction; however, sulfate reduction was not required for the loss of C2H2 to occur. Enrichment cultures were obtained which grew anaerobically at the expense of C2H2.

TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS

EPA Science Inventory

The feasibility of photo-oxidation treatment of methyl tert-butyl ether (MTBE) in water was investigated in three ways, 1) using a slurry falling film photo-reactor, 2) a batch solar reactor system, and 3) a combination of air-stripping and gas phase photooxidation system. MTBE-c...

Behaviour and occurrence of estrogens in municipal sewage treatment plants--II. Aerobic batch experiments with activated sludge.

PubMed

Ternes, T A; Kreckel, P; Mueller, J

1999-01-12

Aerobic batch experiments containing a diluted slurry of activated sludge from a real sewage treatment plant (STP) near Frankfurt/Main were undertaken, in order to investigate the persistence of natural estrogens and contraceptives under aerobic conditions. The batch experiments showed that while in contact with activated sludge the natural estrogen 17 beta-estradiol was oxidized to estrone, which was further eliminated in the batch experiments in an approximate linear time dependence. Further degradation products of estrone were not observed. 16 alpha-hydroxyestrone was rapidly eliminated, again without detection of further degradation products. The contraceptive 17 alpha-ethinylestradiol was principally persistent under the selected aerobic conditions, whereas mestranol was rapidly eliminated and small portions of 17 alpha-ethinylestradiol were formed by demethylation. Additionally, two glucuronides of 17 beta-estradiol (17 beta-estradiol-17-glucuronide and 17 beta-estradiol-3-glucuronide) were cleaved in contact with the diluted activated sludge solution and thus 17 beta-estradiol was released. The glucuronidase activity of the activated sludge was further confirmed by the cleavage of 4-methylumbelliferyl-beta-D-glucuronide (MUF-beta-glucuronide) in a solution of a activated sludge slurry and Milli-Q-water (1:100, v/v). The turnover rate obtained was approximately steady state, with a turnover rate of 0.1 mumol/l for the released MUF. Hence, it is very likely that the glucuronic acid moiety of 17 beta-estradiol glucuronides and other estrogen glucuronides become cleaved in a real municipal STP, so that the concentrations of the free estrogens increase.

The University of Arizona program in solid propellants

NASA Technical Reports Server (NTRS)

Ramohalli, Kumar

1989-01-01

The University of Arizona program is aimed at introducing scientific rigor to the predictability and quality assurance of composite solid propellants. Two separate approaches are followed: to use the modern analytical techniques to experimentally study carefully controlled propellant batches to discern trends in mixing, casting, and cure; and to examine a vast bank of data, that has fairly detailed information on the ingredients, processing, and rocket firing results. The experimental and analytical work is described briefly. The principle findings were that: (1) pre- (dry) blending of the coarse and fine ammonium perchlorate can significantly improve the uniformity of mixing; (2) the Fourier transformed IR spectra of the uncured and cured polymer have valuable data on the state of the fuel; (3) there are considerable non-uniformities in the propellant slurry composition near the solid surfaces (blades, walls) compared to the bulk slurry; and (4) in situ measurements of slurry viscosity continuously during mixing can give a good indication of the state of the slurry. Several important observations in the study of the data bank are discussed.

Tribological properties of coal slurries

NASA Technical Reports Server (NTRS)

Fusaro, Robert L.; Schrubens, Dale L.

1987-01-01

A pin-on-disk tribometer was used to study the tribological properties of methyl alcohol-coal slurries. Friction coefficients, steel pin wear rates and wear surface morphological studies were conducted on AISI 440C HT and M-50 bearing steels which were slid dry and in solutions of methyl alcohol, methyl alcohol-fine coal particles, and methyl alcohol-fine coal particles-flocking additive. The latter was an oil derived from coal and originally intended to be added to the coal slurry to improve the sedimentation and rheology properties. The results of this study indicated that the addition of the flocking additive to the coal slurry markedly improved the tribological properties, especially wear. In addition, the type of steel was found to be very important in determining the type of wear that took place. Cracks and pits were found on the M-50 steel pin wear surfaces that slid in the coal slurries while 440C HT steel pins showed none.

Using molecular-scale tracers to investigate transport of agricultural pollutants in soil and water

NASA Astrophysics Data System (ADS)

Lloyd, C.; Michaelides, K.; Chadwick, D.; Dungait, J.; Evershed, R. P.

2012-12-01

We explore the use of molecular-scale tracers to investigate the transport of potential pollutants due to the application of slurry to soil. The molecular-scale approach allows us to separate the pollutants which are moved to water bodies through sediment-bound and dissolved transport pathways. Slurry is applied to agricultural land to as a soil-improver across a wide-range of topographic and climatic regimes, hence a set of experiments were designed to assess the effect of changing slope gradient and rainfall intensity on the transport of pollutants. The experiments were carried out using University of Bristol's TRACE (Test Rig for Advancing Connectivity Experiments) facility. The facility includes a dual axis soil slope (6 x 2.5 x 0.3 m3) and 6-nozzle rainfall simulator, which enables the manipulation of the slope to simulate different slope gradient and rainfall scenarios. Cattle slurry was applied to the top 1 metre strip of the experimental soil slope followed by four rainfall simulations, where the gradient (5° & 10°) and the rainfall intensity (60 & 120 mm hr-1) were co-varied. Leachate was sampled from different flow pathways (surface, subsurface and percolated) via multiple outlets on the slope throughout the experiments and soil cores were taken from the slope after each experiment. Novel tracers were used to trace the pollutants in both dissolved and sediment-bound forms. Fluorescence spectroscopy was used to trace dissolved slurry-derived material via water flow pathways, as the slurry was found to have a distinct signature compared with the soil. The fluorescence signatures of the leachates were compared with those of many organic compounds in order to characterise the origin of the signal. This allowed the assessment of the longevity of the signal in the environment to establish if it could be used as a robust long-term tracer of slurry material in water or if would be subject to transform processes through time. 5-βstanols, organic compounds unique to ruminant faeces, were used to trace the transport of sediment-bound pollutants from the slurry which could be transported into water bodies via erosion processes. The results showed that contributions of potential pollutants from the surface and subsurface flow pathways and from the eroded sediment differ according to slope gradient and rainfall intensity. Therefore, as the contribution of each of these pathways changes in response to rainfall and slope gradient, the pollution risk also changes accordingly, as different organic compounds are mobilised at varying rates. Rapid hydrological response to rainfall results in erosion and surface transport of sediment-bound and dissolved pollutants, creating an immediate contamination threat. However, conditions resulting in a slower hydrological response and the predominance of flow percolation over surface runoff results in higher rates of dissolved pollutant transport through the soil layers which risks contamination of subsurface and deeper ground-water systems. These experiments provide insight into the pathways and timing of contaminant transport with potential implications for understanding contamination risk from the transfer of slurry from land to water bodies. Understanding this threat is critical at a time when pressure is on to develop land-management strategies to reduce pollution alongside maintaining food security.

Electricity generation by anaerobic bacteria and anoxic sediments from hypersaline soda lakes

USGS Publications Warehouse

Miller, L.G.; Oremland, R.S.

2008-01-01

Anaerobic bacteria and anoxic sediments from soda lakes produced electricity in microbial fuel cells (MFCs). No electricity was generated in the absence of bacterial metabolism. Arsenate respiring bacteria isolated from moderately hypersaline Mono Lake (Bacillus selenitireducens), and salt-saturated Searles Lake, CA (strain SLAS-1) oxidized lactate using arsenate as the electron acceptor. However, these cultures grew equally well without added arsenate using the MFC anode as their electron acceptor, and in the process oxidized lactate more efficiently. The decrease in electricity generation by consumption of added alternative electron acceptors (i.e. arsenate) which competed with the anode for available electrons proved to be a useful indicator of microbial activity and hence life in the fuel cells. Shaken sediment slurries from these two lakes also generated electricity, with or without added lactate. Hydrogen added to sediment slurries was consumed but did not stimulate electricity production. Finally, electricity was generated in statically incubated "intact" sediment cores from these lakes. More power was produced in sediment from Mono Lake than from Searles Lake, however microbial fuel cells could detect low levels of metabolism operating under moderate and extreme conditions of salt stress. ?? 2008 US Government.

Enhanced methane production via repeated batch bioaugmentation pattern of enriched microbial consortia.

PubMed

Yang, Zhiman; Guo, Rongbo; Xu, Xiaohui; Wang, Lin; Dai, Meng

2016-09-01

Using batch and repeated batch cultivations, this study investigated the effects of bioaugmentation with enriched microbial consortia (named as EMC) on methane production from effluents of hydrogen-producing stage of potato slurry, as well as on the indigenous bacterial community. The results demonstrated that the improved methane production and shift of the indigenous bacterial community structure were dependent on the EMC/sludge ratio and bioaugmentation patterns. The methane yield and production rate in repeated batch bioaugmentation pattern of EMC were, respectively, average 15% and 10% higher than in one-time bioaugmentation pattern of EMC. DNA-sequencing approach showed that the enhanced methane production in the repeated batch bioaugmentation pattern of EMC mainly resulted from the enriched iron-reducing bacteria and the persistence of the introduced Syntrophomonas, which led to a rapid degradation of individual VFAs to methane. The findings contributed to understanding the correlation between the bioaugmentation of microbial consortia, community shift, and methane production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Magnetic sorbents added to soil slurries lower Cr aqueous concentration

NASA Astrophysics Data System (ADS)

Aravantinos, Konstantinos; Isari, Ekavi; Karapanagioti, Hrissi K.; Manariotis, Ioannis D.; Werner, David

2016-04-01

Activated carbon (AC) acts as a strong binding agent that lowers the pollutant concentration and, thus its toxicity. Another promising sorbent material in environmental applications is biochar (BC) which is obtained from the incomplete combustion of carbon-rich biomass under oxygen-limited conditions. Both of these materials could be used as soil or sediment amendments that would lower the toxicity in the aqueous phase. A draw back of this technique is that although the pollutant will remain non- bioavailable for many years being sorbed into these sorbents, it actually stays into the system. The objective of this study was (a) to synthesize a magnetic powdered activated carbon (AC/Fe) and magnetic powdered biochar (BC/Fe) produced from a commercial AC sample and BC, respectively and (b) to evaluate the potential use of AC/Fe and BC/Fe to lower Cr concentration that desorb from two soils in their soil slurries. The two soil samples originate from the vicinity of a local metal shop. The BC was produced from olive pomace. The surface area, the pore volume, and the average pore size of each sorbent were determined using gas (N2) adsorption-desorption cycles and the Brunauer, Emmett, and Teller (BET) equation. Isotherms with 30 adsorption and 20 desorption points were conducted at liquid nitrogen temperature (77K). Open surface area and micropore volume were determined using t-plot method and Harkins & Jura equation. For both AC/Fe, surface area measurements resulted in 66% those of corresponding AC. For BC/Fe, the surface area was 82% that of BC. Our previous studies have shown that both AC/Fe and BC/Fe are effective sorbents for mercury in aqueous solutions but with lower sorption capacity compared to the initial materials (50-75% lower). Batch experiments with all sorbent samples and each soil were conducted at room temperature (25oC) in order to compare the sorption properties of the materials. The soil slurries demonstrated low Cr concentrations (10.9 and 14.6 μg/L, respectively). One month after the addition of amendments AC, AC/Fe, and BC/Fe, Cr concentration in the slurry was lower than the detection limit which was 0.5 μg/L (except of one of the soils with the AC that was 2.1 μg/L). The slurries with BC demonstrated Cr concentrations equal to 4.2 and 7.1 μg/L, respectively. All these properties point to promising materials that can effectively be used for in-situ environmental remediation and also be recovered.

Gravitational sedimentation of flocculated waste activated sludge.

PubMed

Chu, C P; Lee, D J; Tay, J H

2003-01-01

The sedimentation characteristics of flocculated wastewater sludge have not been satisfactorily explored using the non-destructive techniques, partially owing to the rather low solid content (ca. 1-2%) commonly noted in the biological sediments. This paper investigated, for the first time, the spatial-temporal gravitational settling characteristics of original and polyelectrolyte flocculated waste activated sludge using Computerized Axial Tomography Scanner. The waste activated sludge possessed a distinct settling characteristic from the kaolin slurries. The waste activated sludges settled more slowly and reached a lower solid fraction in the final sediment than the latter. Flocculation markedly enhanced the settleability of both sludges. Although the maximum achievable solid contents for the kaolin slurries were reduced, flocculation had little effects on the activated sludge. The purely plastic rheological model by Buscall and White (J Chem Soc Faraday Trans 1(83) (1987) 873) interpreted the consolidating sediment data, while the purely elastic model by Tiller and Leu (J. Chin. Inst. Chem. Eng. 11 (1980) 61) described the final equilibrated sediment. Flocculation produced lower yield stress during transient settling, thereby resulting in the more easily consolidated sludge than the original sample. Meanwhile, the flocculated activated sludge was stiffer in the final sediment than in the original sample. The data reported herein are valuable to the theories development for clarifier design and operation.

Effects of cattle manure on erosion rates and runoff water pollution by faecal coliforms.

PubMed

Ramos, M C; Quinton, J N; Tyrrel, S F

2006-01-01

The large quantities of slurry and manure that are produced annually in many areas in which cattle are raised could be an important source of organic matter and nutrients for agriculture. However, the benefits of waste recycling may be partially offset by the risk of water pollution associated with runoff from the fields to which slurry or manure has been applied. In this paper, the effects of cattle manure application on soil erosion rates and runoff and on surface water pollution by faecal coliforms are analysed. Rainfall simulations at a rate of 70 mm h(-1) were conducted in a sandy loam soil packed into soil flumes (2.5m long x 1m wide) at a bulk density of 1400 kg m(-3), with and without cattle slurry manure applied on the surface. For each simulation, sediment and runoff rates were analysed and in those simulations with applied slurry, presumptive faecal coliform (PFC) concentrations in the runoff were evaluated. The application of slurry on the soil surface appeared to have a protective effect on the soils, reducing soil detachment by up to 70% but increasing runoff volume by up to 30%. This practice implies an important source of pollution for surface waters especially if rainfall takes place within a short period after application. The concentrations of micro-organisms (presumptive faecal coliforms (PFCs)) found in water runoff ranged from 1.9 x 10(4) to 1.1 x 10(6) PFC 100mL(-1), depending on the initial concentration in the slurry, and they were particularly high during the first phases of the rainfall event. The result indicates a strong relationship between the faecal coliforms transported by runoff and the organic matter in the sediment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poirier, M.; Burket, P.

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. SRR requested SRNL to conduct bench-scale filter tests to evaluate whether sodium oxalate, sodiummore » aluminosilicate, or aluminum solids (i.e., gibbsite and boehmite) could be the cause of excessive fouling of the crossflow or secondary filter at ARP. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate, 2.5 g MST/L slurry, and varying concentrations of sodium oxalate, sodium aluminosilicate, and aluminum solids, processing the slurry through a bench-scale filter unit that contains a crossflow primary filter and a dead-end secondary filter, and measuring filter flux and transmembrane pressure as a function of time. Among the conclusions drwn from this work are the following: (1) All of the tests showed some evidence of fouling the secondary filter. This fouling could be from fine particles passing through the crossflow filter. (2) The sodium oxalate-containing feeds behaved differently from the sodium aluminosilicate- and gibbsite/boehmite-containing feeds.« less

The influence of additives on rheological properties of limestone slurry

NASA Astrophysics Data System (ADS)

Jaworska, B.; Bartosik, A.

2014-08-01

Limestone slurry appears in the lime production process as the result of rinsing the processed material. It consists of particles with diameter smaller than 2 mm and the water that is a carrier of solid fraction. Slurry is directed to the settling tank, where the solid phase sediments and the excess water through the transfer system is recovered for re-circulation. Collected at the bottom of the tank sludge is deposited in a landfill located on the premises. Rheological properties of limestone slurry hinder its further free transport in the pipeline due to generated flow resistance. To improve this state of affairs, chemical treatment of drilling fluid, could be applied, of which the main task is to give the slurry properties suitable for the conditions encountered in hydrotransport. This treatment consists of applying chemical additives to slurry in sufficient quantity. Such additives are called as deflocculants or thinners or dispersants, and are chemical compounds which added to aqueous solution are intended to push away suspended particles from each other. The paper presents the results of research allowing reduction of shear stress in limestone slurry. Results demonstrate rheological properties of limestone slurry with and without the addition of modified substances which causes decrease of slurry viscosity, and as a consequence slurry shear stress for adopted shear rate. Achieving the desired effects increases the degree of dispersion of the solid phase suspended in the carrier liquid and improving its ability to smooth flow with decreased friction.

Anaerobic degradation of benzene in diverse anoxic environments

USGS Publications Warehouse

Kazumi, J.; Caldwell, M.E.; Suflita, J.M.; Lovely, D.R.; Young, L.Y.

1997-01-01

Benzene has often been observed to be resistant to microbial degradation under anoxic conditions. A number of recent studies, however, have demonstrated that anaerobic benzene utilization can occur. This study extends the previous reports of anaerobic benzene degradation to sediments that varied with respect to contamination input, predominant redox condition, and salinity. In spite of differences in methodology, microbial degradation of benzene was noted in slurries constructed with sediments from various geographical locations and range from aquifer sands to fine-grained estuarine muds, under methanogenic, sulfate-reducing, and iron-reducing conditions. In aquifer sediments under methanogenic conditions, benzene loss was concomitant with methane production, and microbial utilization of [14C]benzene yielded 14CO2 and 14CH4. In slurries with estuarine and aquifer sediments under sulfate-reducing conditions, the loss of sulfate in amounts consistent with the stoichiometric degradation of benzene or the conversion of [14C]benzene to 14CO2 indicates that benzene was mineralized. Benzene loss also occurred in the presence of Fe(III) in sediments from freshwater environments. Microbial benzene utilization, however, was not observed under denitrifying conditions. These results indicate that the potential for the anaerobic degradation of benzene, which was once thought to be resistant to non-oxygenase attack, exists in a variety of aquatic sediments from widely distributed locations.

Regiospecific dechlorination of pentachlorophenol by dichlorophenol-adapted microorganisms in freshwater, anaerobic sediment slurries.

PubMed Central

Bryant, F O; Hale, D D; Rogers, J E

1991-01-01

The reductive dechlorination of pentachlorophenol (PCP) was investigated in anaerobic sediments that contained nonadapted or 2,4- or 3,4-dichlorophenol (DCP)-adapted microbial communities. Adaptation of sediment communities increased the rate of conversion of 2,4- or 3,4-DCP to monochlorophenols (CPs) and eliminated the lag phase before dechlorination was observed. Both 2,4- and 3,4-DCP-adapted sediment communities dechlorinated the six DCP isomers to CPs. The specificity of chlorine removal from the DCP isomers indicated a preference for ortho-chlorine removal by 2,4-DCP-adapted sediment communities and for para-chlorine removal by 3,4-DCP-adapted sediment communities. Sediment slurries containing nonadapted microbial communities either did not dechlorinate PCP or did so following a lag phase of at least 40 days. Sediment communities adapted to dechlorinate 2,4- or 3,4-DCP dechlorinated PCP without an initial lag phase. The 2,4-DCP-adapted communities initially removed the ortho-chlorine from PCP, whereas the 3,4-DCP-adapted communities initially removed the para-chlorine from PCP. A 1:1 mixture of the adapted sediment communities also dechlorinated PCP without a lag phase. Dechlorination by the mixture was regiospecific, following a para greater than ortho greater than meta order of chlorine removal. Intermediate products of degradation, 2,3,5,6-tetrachlorophenol, 2,3,5-trichlorophenol, 3,5-DCP, 3-CP, and phenol, were identified by a combination of cochromatography (high-pressure liquid chromatography) with standards and gas chromatography-mass spectrometry. PMID:1768102

Regeneration of barium carbonate from barium sulphide in a pilot-scale bubbling column reactor and utilization for acid mine drainage.

PubMed

Mulopo, J; Zvimba, J N; Swanepoel, H; Bologo, L T; Maree, J

2012-01-01

Batch regeneration of barium carbonate (BaCO(3)) from barium sulphide (BaS) slurries by passing CO(2) gas into a pilot-scale bubbling column reactor under ambient conditions was used to assess the technical feasibility of BaCO(3) recovery in the Alkali Barium Calcium (ABC) desalination process and its use for sulphate removal from high sulphate Acid Mine Drainage (AMD). The effect of key process parameters, such as BaS slurry concentration and CO(2) flow rate on the carbonation, as well as the extent of sulphate removal from AMD using the recovered BaCO(3) were investigated. It was observed that the carbonation reaction rate for BaCO(3) regeneration in a bubbling column reactor significantly increased with increase in carbon dioxide (CO(2)) flow rate whereas the BaS slurry content within the range 5-10% slurry content did not significantly affect the carbonation rate. The CO(2) flow rate also had an impact on the BaCO(3) morphology. The BaCO(3) recovered from the pilot-scale bubbling column reactor demonstrated effective sulphate removal ability during AMD treatment compared with commercial BaCO(3).

Optimizing contaminant desorption and bioavailability in dense slurry systems. 2. PAH bioavailability and rates of degradation.

PubMed

Kim, Han S; Weber, Walter J

2005-04-01

The effects of mechanical mixing on rates of polycyclic aromatic hydrocarbon (PAH) biodegradation in dense geosorbent slurry (67% solids content, w/w) systems were evaluated using laboratory-scale intermittently mixed batch bioreactors. A PAH-contaminated soil and a phenanthrene-sorbed mineral sorbent (alpha-Al2O3) were respectively employed as slurry solids in aerobic and anaerobic biodegradation studies. Both slurries exhibited a characteristic behavior of pseudoplastic non-Newtonian fluids, and the impeller revolution rate and its diameter had dramatic impacts on power and torque requirements in their laminar flow mixing. Rates of phenanthrene biodegradation were markedly enhanced by relatively low-level auger mixing under both aerobic and anaerobic (denitrifying) conditions. Parameters for empirical models correlating biodegradation rate coefficient (k(b)) values to the degree of mixing were similar to those for correlations between mass transfer (desorption) rate coefficient (k(r)) values for rapidly desorbing fractions of soil organic matter and degree of mixing reported in a companion study, supporting a conclusion that performance-efficient and cost-effective enhancements of PAH mass transfer (desorption) and its biodegradation processes can be achieved by the introduction of optimal levels of reactor-scale mechanical mixing.

Determination of heat conductivity of waste glass feed and its applicability for modeling the batch-to-glass conversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hujova, Miroslava; Pokorny, Richard; Klouzek, Jaroslav

The heat conductivity of reacting melter feed affects the heat transfer and conversion process in the cold cap (the reacting feed floating on molten glass). To investigate it, we simulated the feed conditions and morphology in the cold-cap by preparing “fast-dried slurry blocks”, formed by rapidly evaporating water from feed slurry poured onto a 200°C surface. A heat conductivity meter was used to measure heat conductivity of samples cut from the fast-dried slurry blocks, samples of a cold cap retrieved from a laboratory-scale melter, and loose dry powder feed samples. Our study indicates that the heat conductivity of the feedmore » in the cold cap is significantly higher than that of loose dry powder feed, resulting from the feed solidification during the water evaporation from the feed slurry. To assess the heat transfer at higher temperatures when feed turns into foam, we developed a theoretical model that predicts the foam heat conductivity based on morphology data from in-situ X-ray computed tomography. The implications for the mathematical modeling of the cold cap are discussed.« less

Improving the stability of coal slurries. Quarterly progress report, March 15-June 15, 1986. [Sedimentation tests in the presence and absence of gum tragacanth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fogler, H.S.

1986-01-01

In this report, we will describe the progress of our research in two key areas. The twin objectives of this research are: (a) to examine the effectiveness of hydrocolloids as stabilizers of coal-water slurries and (b) to gain an understanding of the mechanism of stabilization through the use of monodisperse polystyrene lattices as model systems. Sedimentation tests with ultrafine ground coal in presence and absence of gum tragacanth have been carried out. An isotherm of gum tragacanth binding to coal surface has been generated. We have also conducted rheological studies to characterize the stabilized coal-water slurries. Similar experiments with -200more » mesh coal are currently under way. In the case of model system studies, the effect of article size on the gum tragacanth induced stability has been studied. Initial experiments on the effects of increased electrolyte concentration and the addition of nonsolvents like ethanol to the continuous phase have been undertaken. 9 refs., 16 figs., 1 tab.« less

Bacterial dissimilatory reduction of arsenic(V) to arsenic(III) in anoxic sediments

USGS Publications Warehouse

Dowdle, P.R.; Laverman, A.M.; Oremland, R.S.

1996-01-01

Incubation of anoxic salt marsh sediment slurries with 10 mM As(V) resulted in the disappearance over time of the As(V) in conjunction with its recovery as As(III). No As(V) reduction to As(III) occurred in heat- sterilized or formalin-killed controls or in live sediments incubated in air. The rate of As(V) reduction in slurries was enhanced by addition of the electron donor lactate, H2, or glucose, whereas the respiratory inhibitor/uncoupler dinitrophenol, rotenone, or 2-heptyl-4-hydroxyquinoline N-oxide blocked As(V) reduction. As(V) reduction was also inhibited by tungstate but not by molybdate, sulfate, or phosphate. Nitrate inhibited As(V) reduction by its action as a preferred respiratory electron acceptor rather than as a structural analog of As(V). Nitrate-respiring sediments could reduce As(V) to As(III) once all the nitrate was removed. Chloramphenicol blocked the reduction of As(V) to As(III) in nitrate- respiring sediments, suggesting that nitrate and arsenate were reduced by separate enzyme systems. Oxidation of [2-14C]acetate to 14CO2 by salt marsh and freshwater sediments was coupled to As(V). Collectively, these results show that reduction of As(V) in sediments proceeds by a dissimilatory process. Bacterial sulfate reduction was completely inhibited by As(V) as well as by As(III).

Optimization of high solids fed-batch saccharification of sugarcane bagasse based on system viscosity changes.

PubMed

Liu, Yunyun; Xu, Jingliang; Zhang, Yu; Yuan, Zhenhong; Xie, Jun

2015-10-10

Viscosity trends in alkali-pretreated sugarcane bagasse (SCB) slurries undergoing high solids fed-batch enzymatic hydrolysis were measured for a range of solids loading from 15% to 36%. Solids liquefaction times were related to system viscosity changes. The viscosity decreased quickly for low solids loading, and increased with increasing solids content. Fed-batch hydrolysis was initiated with 15% solids loading, and an additional 8%, 7% and 6% were successively added after the system viscosity decreased to stable values to achieve a final solids content of 36%. Two enzyme-adding modes with 8.5FPU/g solid were investigated. The batch mode with all enzyme being added at the beginning of the reaction produced the highest yields, with approximately 231.7g/L total sugars and 134.9g/L glucose being obtained after 96h with nearly 60% of the final glucan conversion rate. This finding indicates that under the right conditions, the fed-batch strategy might be a plausible way to produce high sugars under high solids. Copyright © 2015 Elsevier B.V. All rights reserved.

Restoring Ecological Function to a Submerged Salt Marsh

USGS Publications Warehouse

Stagg, C.L.; Mendelssohn, I.A.

2010-01-01

Impacts of global climate change, such as sea level rise and severe drought, have altered the hydrology of coastal salt marshes resulting in submergence and subsequent degradation of ecosystem function. A potential method of rehabilitating these systems is the addition of sediment-slurries to increase marsh surface elevation, thus ameliorating effects of excessive inundation. Although this technique is growing in popularity, the restoration of ecological function after sediment addition has received little attention. To determine if sediment subsidized salt marshes are functionally equivalent to natural marshes, we examined above- and belowground primary production in replicated restored marshes receiving four levels of sediment addition (29-42 cm North American Vertical Datum of 1988 [NAVD 88]) and in degraded and natural ambient marshes (4-22 cm NAVD 88). Moderate intensities of sediment-slurry addition, resulting in elevations at the mid to high intertidal zone (29-36 cm NAVD 88), restored ecological function to degraded salt marshes. Sediment additions significantly decreased flood duration and frequency and increased bulk density, resulting in greater soil drainage and redox potential and significantly lower phytotoxic sulfide concentrations. However, ecological function in the restored salt marsh showed a sediment addition threshold that was characterized by a decline in primary productivity in areas of excessive sediment addition and high elevation (>36 cm NAVD 88). Hence, the addition of intermediate levels of sediment to submerging salt marshes increased marsh surface elevation, ameliorated impacts of prolonged inundation, and increased primary productivity. However, too much sediment resulted in diminished ecological function that was equivalent to the submerged or degraded system. ?? 2010 Society for Ecological Restoration International.

Efficient production of ethanol from waste paper and the biochemical methane potential of stillage eluted from ethanol fermentation.

PubMed

Nishimura, Hiroto; Tan, Li; Sun, Zhao-Yong; Tang, Yue-Qin; Kida, Kenji; Morimura, Shigeru

2016-02-01

Waste paper can serve as a feedstock for ethanol production due to being rich in cellulose and not requiring energy-intensive thermophysical pretreatment. In this study, an efficient process was developed to convert waste paper to ethanol. To accelerate enzymatic saccharification, pH of waste paper slurry was adjusted to 4.5-5.0 with H2SO4. Presaccharification and simultaneous saccharification and fermentation (PSSF) with enzyme loading of 40 FPU/g waste paper achieved an ethanol yield of 91.8% and productivity of 0.53g/(Lh) with an ethanol concentration of 32g/L. Fed-batch PSSF was used to decrease enzyme loading to 13 FPU/g waste paper by feeding two separate batches of waste paper slurry. Feeding with 20% w/w waste paper slurry increased ethanol concentration to 41.8g/L while ethanol yield decreased to 83.8%. To improve the ethanol yield, presaccharification was done prior to feeding and resulted in a higher ethanol concentration of 45.3g/L, a yield of 90.8%, and productivity of 0.54g/(Lh). Ethanol fermentation recovered 33.2% of the energy in waste paper as ethanol. The biochemical methane potential of the stillage eluted from ethanol fermentation was 270.5mL/g VTS and 73.0% of the energy in the stillage was recovered as methane. Integrating ethanol fermentation with methane fermentation, recovered a total of 80.4% of the energy in waste paper as ethanol and methane. Copyright © 2015 Elsevier Ltd. All rights reserved.

MEASUREMENT OF HYDROXYL RADICAL ACTIVITY IN A SOIL SLURRY USING THE SPIN TRAP A-(4-PYRIDYL-1-OXIDE)-N-TERT-BUTYLNITRONE

EPA Science Inventory

The spin trap compound a-(4-pyridyl-1-oxide)N-tert-butylnitrone (4-POBN) served as a probe to estimate the activity of Fenton-derived hydroxyl radicals (.OH) in a batch suspension comprised of silica sand and crushes goethite ore. The rate of probe disappearance was used to anal...

Characterization Of The As-Received Sludge Batch 9 Qualification Sample (Htf-51-15-81)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.

Savannah River National Laboratory (SRNL) personnel have been requested to qualify the next sludge batch (Sludge Batch 9 – SB9) for processing at the Defense Waste Processing Facility (DWPF). To accomplish this task, Savannah River Remediation (SRR) has sent SRNL a 3-L slurried sample of Tank 51H (HTF-51-15-81) to be characterized, washed, and then used in a lab-scale demonstration of the DWPF flowsheet (potentially after combining with Tank 40H sludge). This report documents the first steps of the qualification process – characterization of the as-received Tank 51H qualification sample. These results will be used to support a reprojection of SB9more » by SRR from which final Tank 51H washing, frit development, and Chemical Processing Cell (CPC) activities will be based.« less

Recovering low-turbidity cutting liquid from silicon slurry waste.

PubMed

Tsai, Tzu-Hsuan; Shih, Yu-Pei

2014-04-30

In order to recover a low-turbidity polyalkylene glycol (PAG) liquid from silicon slurry waste by sedimentation, temperatures were adjusted, and acetone, ethanol or water was used as a diluent. The experimental results show that the particles in the waste would aggregate and settle readily by using water as a diluent. This is because particle surfaces had lower surface potential value and weaker steric stabilization in PAG-water than in PAG-ethanol or PAG-acetone solutions. Therefore, water is the suggested diluent for recovering a low-turbidity PAG (<100 NTU) by sedimentation. After 50 wt.% water-assisted sedimentation for 21 days, the solid content of the upper liquid reduced to 0.122 g/L, and the turbidity decreased to 44 NTU. The obtained upper liquid was then vacuum-distillated to remove water. The final recovered PAG with 0.37 NTU had similar viscosity and density to the unused PAG and could be reused in the cutting process. Copyright © 2014 Elsevier B.V. All rights reserved.

Low frequency aeration of pig slurry affects slurry characteristics and emissions of greenhouse gases and ammonia.

PubMed

Calvet, Salvador; Hunt, John; Misselbrook, Tom H

2017-07-01

Low frequency aeration of slurries may reduce ammonia (NH 3 ) and methane (CH 4 ) emissions without increasing nitrous oxide (N 2 O) emissions. The aim of this study was to quantify this potential reduction and to establish the underlying mechanisms. A batch experiment was designed with 6 tanks with 1 m 3 of pig slurry each. After an initial phase of 7 days when none of the tanks were aerated, a second phase of 4 weeks subjected three of the tanks to aeration (2 min every 6 h, airflow 10 m 3  h -1 ), whereas the other three tanks remained as a control. A final phase of 9 days was established with no aeration in any tank. Emissions of NH 3 , CH 4 , carbon dioxide (CO 2 ) and N 2 O were measured. In the initial phase no differences in emissions were detected, but during the second phase aeration increased NH 3 emissions by 20% with respect to the controls (8.48 vs. 7.07 g m -3  [slurry] d -1 , P < 0.05). A higher pH was found in the aerated tanks at the end of this phase (7.7 vs. 7.0 in the aerated and control tanks, respectively, P < 0.05). CH 4 emissions were 40% lower in the aerated tanks (2.04 vs. 3.39 g m -3  [slurry] d -1 , P < 0.05). These differences in NH 3 and CH 4 emissions remained after the aeration phase had finished. No effect was detected for CO 2 , and no relevant N 2 O emissions were detected during the experiment. Our results demonstrate that low frequency aeration of stored pig slurry increases slurry pH and increases NH 3 emissions.

Microbial oxidation of elemental selenium in soil slurries and bacterial cultures

USGS Publications Warehouse

Dowdle, P.R.; Oremland, R.S.

1998-01-01

The microbial oxidation of elemental selenium [Se(O)] was studied by employing 75Se(O) as a tracer. Live, oxic soil slurries demonstrated a linear production of mostly Se(IV), with the formation of smaller quantities of Se(VI). Production of both Se(IV) and Se(VI) was inhibited by autoclaving, formalin, antibiotics, azide, and 2,4-dinitrophenol, thereby indicating the involvement of microbes. Oxidation of Se(O) in slurries was enhanced by addition of acetate, glucose, or sulfide, which implied involvement of chemoheterotrophs as well as chemoautotrophic thiobacilli. Cultures of Thiobacillus ASN-1, Leptothrix MnB1, and a heterotrophic soil enrichment all oxidized Se(O) with Se(VI) observed as the major product rather than Se(IV). This indicated that microbial oxidation in soils is partly constrained by the adsorption of Se(IV) onto soil surfaces. Rate constants for unamended soil slurry Se(O) oxidation ranged from 0.0009 to 0.0117 day-1 which were 3-4 orders of magnitude lower than those reported for dissimilatory Se(VI) reduction in organic-rich, anoxic sediments.The microbial oxidation of elemental selenium [Se(0)] was studied by employing 75Se(0) as a tracer. Live, oxic soil slurries demonstrated a linear production of mostly Se(IV), with the formation of smaller quantities of Se(VI). Production of both Se(IV) and Se(VI) was inhibited by autoclaving, formalin, antibiotics, azide, and 2,4-dinitrophenol, thereby indicating the involvement of microbes. Oxidation of Se(O) in slurries was enhanced by addition of acetate, glucose, or sulfide, which implied involvement of chemoheterotrophs as well as chemoautotrophic thiobacilli. Cultures of Thiobacillus ASN-1, Leptothrix MnB1, and a heterotrophic soil enrichment all oxidized Se(O) with Se(VI) observed as the major product rather than Se(IV). This indicated that microbial oxidation in soils is partly constrained by the adsorption of Se(IV) onto soil surfaces. Rate constants for unamended soil slurry Se(O) oxidation ranged from 0.0009 to 0.0117 day-1 which were 3-4 orders of magnitude lower than those reported for dissimilatory Se(VI) reduction in organic-rich, anoxic sediments.

Phosphate-Induced Immobilization of Uranium in Hanford Sediments.

PubMed

Pan, Zezhen; Giammar, Daniel E; Mehta, Vrajesh; Troyer, Lyndsay D; Catalano, Jeffrey G; Wang, Zheming

2016-12-20

Phosphate can be added to subsurface environments to immobilize U(VI) contamination. The efficacy of immobilization depends on the site-specific groundwater chemistry and aquifer sediment properties. Batch and column experiments were performed with sediments from the Hanford 300 Area in Washington State and artificial groundwater prepared to emulate the conditions at the site. Batch experiments revealed enhanced U(VI) sorption with increasing phosphate addition. X-ray absorption spectroscopy measurements of samples from the batch experiments found that U(VI) was predominantly adsorbed at conditions relevant to the column experiments and most field sites (low U(VI) loadings, <25 μM), and U(VI) phosphate precipitation occurred only at high initial U(VI) (>25 μM) and phosphate loadings. While batch experiments showed the transition of U(VI) uptake from adsorption to precipitation, the column study was more directly relevant to the subsurface environment because of the high solid:water ratio in the column and the advective flow of water. In column experiments, nearly six times more U(VI) was retained in sediments when phosphate-containing groundwater was introduced to U(VI)-loaded sediments than when the groundwater did not contain phosphate. This enhanced retention persisted for at least one month after cessation of phosphate addition to the influent fluid. Sequential extractions and laser-induced fluorescence spectroscopy of sediments from the columns suggested that the retained U(VI) was primarily in adsorbed forms. These results indicate that in situ remediation of groundwater by phosphate addition provides lasting benefit beyond the treatment period via enhanced U(VI) adsorption to sediments.

Phosphate-Induced Immobilization of Uranium in Hanford Sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Zezhen; Giammar, Daniel E.; Mehta, Vrajesh

2016-12-20

Phosphate can be added to subsurface environments to immobilize U(VI) contamination. The efficacy of immobilization depends on the site-specific groundwater chemistry and aquifer sediment properties. Batch and column experiments were performed with sediments from the Hanford 300 Area in Washington State and artificial groundwater prepared to emulate the conditions at the site. Batch experiments revealed enhanced U(VI) sorption with increasing phosphate addition. X-ray absorption spectroscopy measurements of samples from the batch experiments found that U(VI) was predominantly adsorbed at conditions relevant to the column experiments and most field sites (low U(VI) loadings, <25 μM), and U(VI) phosphate precipitation occurred onlymore » at high initial U(VI) (>25 μM) and phosphate loadings. While batch experiments showed the transition of U(VI) uptake from adsorption to precipitation, the column study was more directly relevant to the subsurface environment because of the high solid:water ratio in the column and the advective flow of water. In column experiments, nearly six times more U(VI) was retained in sediments when phosphate-containing groundwater was introduced to U(VI)-loaded sediments than when the groundwater did not contain phosphate. This enhanced retention persisted for at least one month after cessation of phosphate addition to the influent fluid. Sequential extractions and laser-induced fluorescence spectroscopy of sediments from the columns suggested that the retained U(VI) was primarily in adsorbed forms. These results indicate that in situ remediation of groundwater by phosphate addition provides lasting benefit beyond the treatment period via enhanced U(VI) adsorption to sediments.« less

Phosphate-Induced Immobilization of Uranium in Hanford Sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Zezhen; Giammar, Daniel E.; Mehta, Vrajesh

2016-12-20

Phosphate can be added to subsurface environments to immobilize U(VI) contamination. The efficacy of immobilization depends on the site-specific groundwater chemistry and aquifer sediment properties. Batch and column experiments were performed with sediments from the Hanford 300 Area in Washington State and artificial groundwater prepared to emulate the conditions at the site. Batch experiments revealed enhanced U(VI) sorption with increasing phosphate addition. X-ray absorption spectroscopy measurements of samples from the batch experiments found that U(VI) was predominantly adsorbed at conditions relevant to the column experiments and most field sites (low U(VI) loadings, <25 μM), and U(VI) phosphate precipitation occurred onlymore » at high initial U(VI) (>25μM) and phosphate loadings. While batch experiments showed the transition of U(VI) uptake from adsorption to precipitation, the column study was more directly relevant to the subsurface environment because of the high solid:water ratio in the column and the advective flow of water. In column experiments, nearly six times more U(VI) was retained in sediments when phosphate-containing groundwater was introduced to U(VI)-loaded sediments than when the groundwater did not contain phosphate. This enhanced retention persisted for at least one month after cessation of phosphate addition to the influent fluid. Sequential extractions and laser-induced fluorescence spectroscopy of sediments from the columns suggested that the retained U(VI) was primarily in adsorbed forms. These results indicate that in situ remediation of groundwater by phosphate addition provides lasting benefit beyond the treatment period via enhanced U(VI) adsorption to sediments.« less

Quantitative determination of microbial activity and community nutritional status in estuarine sediments: evidence for a disturbance artifact

NASA Technical Reports Server (NTRS)

Findlay, R. H.; Pollard, P. C.; Moriarty, D. J.; White, D. C.

1985-01-01

In estuarine sediments with a high degree of vertical heterogeneity in reduced substrate and terminal electron acceptor concentrations, the method of exposure of the microbiota to labeled substrates can introduce a "disturbance artifact" into measures of metabolic activity. The detection of this artifact is based on quantitative measurement of the relative rates of incorporation of [14C]acetate into phospholipid fatty acids (PLFA) and endogenous storage lipid, poly-beta-hydroxyalkanoate (PHA). Previous studies have shown that PLFA synthesis measures cellular growth and that PHA synthesis measures carbon accumulation (unbalanced growth). The "disturbance artifact" of exposure to [14C]acetate was demonstrated by comparing injection of a core with the usual or pore-water replacement or slurry techniques. Only injection of labeled substrate allowed detection of preassay disturbance of the sediment with a garden rake. The raking increased PLFA synthesis with little effect to differences in concentration or distribution of [14C]acetate in the 10-min incubation. Bioturbation induced by sand dollar feeding in estuarine sediment could be detected in an increased PLFA/PHA ratio which was due to decreased PHA synthesis if the addition of labeled substrate was by the injection technique. Addition of labeled precursors to sediment by slurry or pore-water replacement induces greater disturbance artifacts than injection techniques.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scrudato, R.J.; Chiarenzelli, J.R.

An electrochemical peroxidation (ECP) process has been developed and used to degrade polychlorinated biphenyls (PCB) and volatile organic compounds (VOC)-contaminated water, sludge, and sediments at a New York State Federal and State Superfund Site. The process involves passing an oscillating low-amperage (<10 amps) current through steel electrodes immersed in an acidified water or sediment slurry into which hydrogen peroxide (<1,000 ppm) is added. The generated free radicals attack organic compounds, including organo-metallic complexes and refractory compounds including PCBs. PCB degradation ranged from about 30% to 80% in experiments involving Federal Superfund Site sediments; total PCBs were reduced by {approximately}97% tomore » 68%, respectively, in water and slurry collected from a State Superfund subsurface storage tank. VOC bench-scale experiments involved chloroethane, 1,1-dichloroethane, dichloromethane, 1,1,1-trichloroethane, and acetone and after a 3-min ECP treatment, degradation ranged from >94% to about 99.9%. Results indicate the ECP is a viable process to degrade organic contaminants in water and sediment suspensions. Because the treated water suspensions are acidified, select trace metal sorbed to the particulates is solubilized and therefore can be segregated from the particulates, offering a process that simultaneously degrades organic contaminants and separates trace metals. 19 refs., 1 fig., 4 tabs.« less

The contribution of anaerobic ammonium oxidation to nitrogen loss in two temperate eutrophic estuaries

NASA Astrophysics Data System (ADS)

Teixeira, Catarina; Magalhães, Catarina; Joye, Samantha B.; Bordalo, Adriano A.

2014-04-01

Studies of anaerobic ammonium oxidation (anammox) continue to show the significance of this metabolic pathway for the removal of nitrogen (N) in several natural environments, including estuaries. However, the seasonal dynamics of the anammox process and related environmental controls within estuarine systems remains poorly explored. We evaluated the seasonal anammox activity along a salinity gradient in two temperate Atlantic estuaries, the Ave and the Douro (NW Portugal). Anammox potential rates were measured in anaerobic sediment slurries using 15N-labeled NO3- and NH4+ amendments. Production of 29N2 and 30N2 in the slurries was quantified using membrane inlet mass spectrometry (MIMS). Environmental characteristics of the sediment and water column were also monitored. Anammox potentials in the Ave and Douro estuarine sediments varied between 0.8-8.4, and 0-2.9 nmol cm-3 wet sediment h-1, respectively, with high seasonal and spatial fluctuations. Inorganic nitrogen availability emerged as the primary environmental control of anammox activity, while water temperature appeared to modulate seasonal variations. The contribution of anammox to overall N2 production averaged over 20%, suggesting that the role of anammox in removing fixed N from these two systems cannot be neglected.

Effects of total solids concentrations of poultry, cattle, and piggery waste slurries on biogas yield

DOE Office of Scientific and Technical Information (OSTI.GOV)

Itodo, I.N.; Awulu, J.O.

1999-12-01

The effects of total solids concentrations of poultry, cattle and piggery waste slurries on biogas yield was investigated. Twelve laboratory-size anaerobic batch digesters with 25 L volume were constructed and used for the experiments. Three replicates of 5%, 10%, 15%, and 20% TS concentrations of poultry, cattle, and piggery waste slurries were anaerobically digested for a 30-day detention period and gas yield was measured by the method of water displacement. Temperature variation within the digesters was measured with a maximum and minimum thermometer. Anaerobic digestion of the slurries was undertaken in the mesophilic temperature range (20--40 C). The carbon:nitrogen ratiomore » of each of the slurries digested was determined. The carbon content was determined using the wackley-Black method, and nitrogen content was determined by the regular kjeldhal method. The pH was measured weekly during the period of digestion from a digital pH meter. Gas quality (% methane fraction) was also measured weekly from an analyzer. Coefficient of variation was computed to ascertain the status of the digestion process. Analysis of variance was used to determine the significant difference in gas yield at p < 0.05. Duncan's New Multiple Range Test at p < 0.05 was used to analyze the difference in gas yield among the various TS concentrations of the slurries investigated. The results indicate that biogas yield is of the order: 5% TS > 10% TS > 15% TS > 20% TS. This result shows that gas yield increases with decreasing TS concentration of the slurries. The ANOVA showed that the gas yield from the various TS % was significantly different (p < 0.05). DNMRT showed that there was significant difference in gas yield from the slurries and wastetypes investigated. Poultry waste slurries had the greatest gas yield (L CH4/kg TS) as the gas yield from the waste types was of the order: Poultry > Piggery > Cattle. The pH of the slurries was of the range 5.5 to 6.8 (weakly acidic). The C:N of the slurries varied between 6:1 and 9:1. The Coefficient of Variation (CV) for 10 consecutive days of digestion was less than 10% indicating a steady state in all the digesters.« less

Characterization of Tank 51 Sludge Slurry Samples (HTF-51-17-67, -68, -69, -74, -75, and -76) in Support of Sludge Batch 10 Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oji, L. N.; Reboul, S. H.

The Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) Engineering (SRR-E) to provide sample characterization and analyses of Tank 51 sludge samples in support of Sludge Batch (SB) 10. The six Tank 51 sludge samples were sampled and delivered to SRNL in August of 2017. These six Tank 51 sludge samples, after undergoing physical characterizations which included rheology, weight percent total solid, dissolved solids and density measurements, were combined into one composite Tank 51 sample and analyzed for corrosion controls analytes, select radionuclides, chemical elements, density and weight percent total solids.

Bacterial community dynamics in aerated cow manure slurry at different aeration intensities.

PubMed

Hanajima, D; Fukumoto, Y; Yasuda, T; Suzuki, K; Maeda, K; Morioka, R

2011-12-01

This study aimed to characterize microbial community dynamics in aerated cow manure slurry at different aeration intensities. Batch aerobic treatments were set up in 5-l jar fermentor, each containing 3 l of manure slurry; the slurries were subjected to low, medium and high (50, 150 and 250 ml min(-1), respectively) aeration for 9 days. Microbial community composition was determined using terminal restriction fragment length polymorphism and a clone library targeting 16S rRNA genes. High and medium aeration accelerated organic carbon degradation in parallel with the degree of aeration intensity; however, 90% of the initial total organic carbon was retained during low-aeration treatment. During the active stages of organic carbon decomposition, clones belonging to the class Bacilli accumulated. Moreover, Bacilli accumulation occurred earlier under high aeration than under medium aeration. Organic matter degradation was mainly governed by a common microbial assemblage consisting of many lineages belonging to the class Bacilli. The timing of community development differed depending on aeration intensity. This study reports on changes in several environmentally important parameters and the principal microbial assemblage during the pollution-reducing phase of cattle manure aeration treatment. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Slurry hydrocracking of Arab heavy vacuum resid with new bifunctional catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rankel, L.A.

1993-12-31

Co-processing coal with hydrogenated vacuum resids can solubilize coal and aid in metals removals from the hydrotreated resid. Several bifunctional NiW catalysts were evaluated for resid hydrocracking in a slurry reactor. Autoclave runs were made to determine whether a hydrogenative metal function (NiW) plus support with cracking activity might be an effective catalyst for high resid 1000F{degrees}{sup +} conversion, H-content enrichment, deS, and demetallation at low coke make. An Arab Heavy 895{degrees}F{sup +} vacuum resid (262 ppm Ni+V, 5.3% S and 24% CCR) was hydrocracked over sulfided and unsulfided NiW catalysts on alumina, silica-alumina, US-Y, etc. at 800{degrees}F and 2000more » psig hydrogen in a batch reactor and compared to oil soluble mixtures of Ni and W homogenous organometallics. Of the catalysts tested here, results indicate that addition of sulfided NiW/aluminum to slurry type processing might improve hydrogenation activity and produce more 1000{degrees}F{sup +} conversion at a particular severity while generating the low coke make necessary for a continuous process. Once the resid is hydrotreated, coal could be added to the NiW bifunctional catalyst/resid slurry for co-processing.« less

Simultaneous saccharification and fermentation and economic evaluation of ultrasonic and jet cooking pretreatment of corn slurry.

PubMed

Montalbo-Lomboy, Melissa; Khanal, Samir Kumar; van Leeuwen, Johannes Hans; Raman, David Raj; Grewell, David

2011-01-01

The potential of ultrasonics to replace hydrocooking in corn-to-ethanol plants was examined in this study. Batch and continuous experiments were conducted on corn slurry with sonication at a frequency of 20 kHz. Batch mode used a catenoidal horn operated at an amplitude of 144 μm peak-to-peak (p–p) for 90 s. Continuous experiments used a donut horn operating at inner radius amplitude of 12 μm p–p. Jet-cooked samples from the same ethanol plant were compared with ultrasonicated samples. The highest starch-to-ethanol conversion was obtained by the jet-cooked samples with a yield of 74% of the theoretical yield. Batch and continuous sonication achieved 71.2% and 68% conversion, respectively, however, statistical analysis showed no significant difference between the jet cooking and ultrasonication. On the basis of the similar performance, an economic analysis was conducted comparing jet cooking and ultrasonic pretreatment. The analysis showed that the capital cost for the ultrasonics system was ~10 times higher compared to the capital cost of a hydrocooker. However,due to the large energy requirements of hydrocookers, the analysis showed lower total overall costs for continuous ultrasonication than that for jet cooking, assuming the current energy prices. Because of the high utility cost calculated for jet cooking, it is concluded that ultrasonication poses as a more economical option than jet cooking. Overall, the study shows that ultrasonics is a technically and economically viable alternative to jet cooking in dry-grind corn ethanol plant. © 2011 American Institute of Chemical Engineers

Batch co-digestion of multi-component agro-wastes.

PubMed

Misi, S N; Forster, C F

2001-10-01

In certain parts of the developing world conventional energy supplies such as electricity, gas, coal and petroleum by-products are either unavailable, too capital intensive to install, are unjustifiable due to low population densities in some semi-arid regions, or are simply unaffordable to the target population. In Zimbabwe, it has been assessed that only biomass energy can conveniently provide both lighting and space heating. Therefore, means of generating biogas from agricultural and other organic wastes, and to encourage their use is a policy which has been adopted by Zimbabwe's Department of Energy. In this study cattle slurry was mixed with a range of solid wastes and allowed to digest in 11 batch digesters. The mixtures which were used were selected on the basis of centroid design with the objective of determining whether there was either synergism or antagonism. Two trials were carried out, one based on cattle slurry, chicken manure (CM) and molasses (Mol), the other based on sheep and goat manure, chicken manure and surplus activated sludge. The criteria for judging the success of a co-digestion were volatile solids (VS) reduction, total methane production and methane yield. In the first trial, the analysis based on the methane yield showed that there was no antagonism and that the mixture of 30% cattle slurry/30% CM/40% Mol gave a synergistic effect. The analysis based on the VS destruction, however, did show that there was some very slight antagonism. In the second trial, the analysis based on the methane yield showed that there was both antagonism and synergism and that the synergism produced an extra 6.7% methane. The analysis based on the VS destruction also showed that there was both antagonism and synergism but that the effects were small.

Investigating the fate of nitroaromatic (TNT) and nitramine (RDX and HMX) explosives in fractured and pristine soils.

PubMed

Douglas, Thomas A; Walsh, Marianne E; McGrath, Christian J; Weiss, Charles A

2009-01-01

Explosives compounds, known toxins, are loaded to soils on military training ranges predominantly during explosives detonation events that likely fracture soil particles. This study was conducted to investigate the fate of explosives compounds in aqueous slurries containing fractured and pristine soil particles. Three soils were crushed with a piston to emulate detonation-induced fracturing. X-ray diffraction, energy-dispersive X-ray spectrometry, gas adsorption surface area measurements, and scanning electron microscopy were used to quantify and image pristine and fractured soil particles. Aqueous batches were prepared by spiking soils with solutions containing 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 2,4-dinitrotoluene (2,4-DNT). Samples were collected over 92 d and the concentrations of the spiked explosives compounds and TNT transformation products 2-amino-4,6-dinitrotoluene (2ADNT) and 4-amino-2,6-dinitrotoluene (4ADNT) were measured. Our results suggest soil mineralogical and geochemical compositions were not changed during piston-induced fracturing but morphological differences were evident with fractured soils exhibiting more angular surfaces, more fine grained particles, and some microfracturing that is not visible in the pristine samples. TNT, 2,4-DNT, RDX, and HMX exhibited greater analyte loss over time in batch solutions containing fractured soil particles compared to their pristine counterparts. 2ADNT and 4ADNT exhibited greater concentrations in slurries containing pristine soils than in slurries containing fractured soils. Explosives compound transformation is greater in the presence of fractured soil particles than in the presence of pristine soil particles. Our results imply fractured soil particles promote explosive compound transformation and/or explosives compounds have a greater affinity for adsorption to fractured soil particle surfaces.

The use of agricultural substrates to improve methane yield in anaerobic co-digestion with pig slurry: effect of substrate type and inclusion level.

PubMed

Ferrer, Pablo; Cambra-López, María; Cerisuelo, Alba; Peñaranda, David S; Moset, Verónica

2014-01-01

Anaerobic co-digestion of pig slurry with four agricultural substrates (tomato, pepper, persimmon and peach) was investigated. Each agricultural substrate was tested in co-digestion with pig slurry at four inclusion levels: 0%, 15%, 30% and 50%. Inclusion levels consisted in the replacement of the volatile solids (VS) from the pig slurry with the VS from the agricultural substrate. The effect of substrate type and inclusion level on the biochemical methane potential (BMP) was evaluated in a batch assay performed at 35 °C for 100 days. Agricultural substrate's chemical composition was also analyzed and related with BMP. Additionally, Bacteria and Archaea domains together with the four main methanogenic archaeal orders were quantified using quantitative real-time TaqMan polymerase chain reaction (qPCR) at the end of the experiment to determine the influence of agricultural substrate on sludge's microbial composition. Results showed that vegetable substrates (pepper and tomato) had higher lipid and protein content and lower carbohydrates than fruit substrates (persimmon and peach). Among substrates, vegetable substrates showed higher BMP than fruit substrates. Higher BMP values were obtained with increasing addition of agricultural substrate. The replacement of 50% of VS from pig slurry by tomato and pepper increased BMP in 41% and 44%, respectively compared with pig slurry only. Lower increments in BMP were achieved with lower inclusion levels. Results from qPCR showed that total bacteria and total archaea gene concentrations were similar in all combinations tested. Methanomicrobiales gene concentrations dominated over the rest of individual archaeal orders. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of pig slurry on the sorption of sulfonamide antibiotics in soil.

PubMed

Thiele-Bruhn, S; Aust, M O

2004-07-01

Sorption of p-aminobenzoic acid (pABA) and five sulfonamide antibiotics to loess Chernozem topsoil amended with varied additions of pig slurry was investigated in batch trials. In unfertilized soil, partition coefficients (Kd) of sulfonamides ranged from 0.3 to 2.0. Strong sorption nonlinearity (1/n = 0.5 to 0.8) was best fitted by the Freundlich isotherm (R2 = 0.7 to 1.0) and was indicative for specific sorption mechanisms. Adsorption to pig slurry was much stronger, and nondesorbable portions were increased compared with soil. However, in a mixture of soil and slurry (50:1 w/w), sorption of the antibiotics was significantly decreased at a lower concentration range of pABA and the sulfonamides. This was attributed to competitive adsorption of dissolved organic matter (DOM) constituents from manure. An increase in pig slurry amendment resulted in increased total organic matter, DOM concentration, and ionic strength, but pH decreased. As a result, the nonadsorbed portions of pABA, sulfanilamide, and sulfadiazine (logD(ow) < -0.4) ranged from 47% to 82% of the applied concentration in the differently manured substrates. Dissolved fractions of the antibiotics reached a maximum at a soil-slurry ratio of 9:1 and decreased with further addition of manure. This decrease was related to the formation of less-effective DOM associates in solution. The adsorbed and desorbed portions of the less-polar substances--sulfadimidine, sulfadimethoxine, and sulfapyridine (logD(ow) > 0.1)--remained nearly constant in the presence of increased manure input. The pH changes caused by manure amendment strongly affected ionisation status of the latter compounds, thus resulting in increased adsorption, which compensated the mobilizing effect of DOM. It is suggested that the effect of manure be considered in test methods to determine the soil retention of pharmaceutical substances.

Influence of soil-water ratio on the performance of slurry phase bioreactor treating herbicide contaminated soil.

PubMed

Venkata Mohan, S; Ramakrishna, M; Shailaja, S; Sarma, P N

2007-09-01

The influence of soil-water ratio was studied on the performance of the slurry phase bioreactor operated in sequencing batch mode (anoxic-aerobic-anoxic microenvironments) during the bioremediation of soil contaminated with pendimethalin. The performance of the reactors was evaluated at different soil-water ratios (1:5-1:25; at soil loading rate (60 kg of soil/cum-day to 12 kg of soil/cum-day)) keeping the loading rate of pendimethalin constant (133.2 g/kg of soil-day) in six reactors and variable (66.6 g/kg of soil-day to 166.6 g/kg of soil-day) in other four reactors. At 1:20 soil-water ratio, the slurry phase system showed enhanced degradation of substrate (629 microg pendimethalin/g soil). The removal efficiency of pendimethalin in the reactors was dependent on the mass-transfer rates of the substrate from the soil to the aqueous phase. Soil-water ratio and substrate loading rates showed significant influence on the substrate portioning, substrate degradation efficiency and substrate desorption rate.

Nitrogen recovery from pig slurry in a two-chambered bioelectrochemical system.

PubMed

Sotres, A; Cerrillo, M; Viñas, M; Bonmatí, A

2015-10-01

Abiotic batch experiments showed that ammonia migration from anode to cathode was favored by an increase in voltage, from 39.9% to 44.6%, using synthetic media. A slight increase in ammonia migration was observed when using pig slurry, reaching a maximum of 49.9%. In a continuously MFC fed with pig slurry with a stripping/absorption unit coupled to the cathode chamber, the highest nitrogen flux (7.2 g N d(-1) m(-2)) was achieved using buffer as catholyte. Nitrogen flux increased to 10.3 g N d(-1) m(-2) when shifting to MEC mode. A clear improvement in nitrogen flux (25.5 g N d(-1) m(-2)) was observed when using NaCl as catholyte. Besides, ammonia stripping was favored, reaching a nitrogen recovery of 94.3% in the absorption column, due to the high pH reached in the cathode. The microbial community analysis revealed an enrichment of certain taxonomic Eubacterial and Archaeal groups when the system shifted from MFC to MEC mode. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of axial velocity and transmembrane pressure (TMP) on ARP filter performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poirier, M.; Burket, P.

2016-02-29

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. One potential method for increasing filter flux is to adjust the axial velocity andmore » transmembrane pressure (TMP). SRR requested SRNL to conduct bench-scale filter tests to evaluate the effects of axial velocity and transmembrane pressure on crossflow filter flux. The objective of the testing was to determine whether increasing the axial velocity at the ARP could produce a significant increase in filter flux. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate and 2.5 g MST/L, processing the slurry through a bench-scale crossflow filter unit at varying axial velocity and TMP, and measuring filter flux as a function of time.« less

A Preliminary Study of the Preparation of Slurry Fuels from Vaporized Magnesium

NASA Technical Reports Server (NTRS)

Witzke, Walter R; Prok, George M; Walsh, Thomas J

1954-01-01

Slurry fuels containing extremely small particles of magnesium were prepared by concentrating the dilute slurry product resulting from the shock-cooling of magnesium metal vapors with a liquid hydrocarbon spray. A complete description of the equipment and procedure used in preparing the fuel is given. Ninety-five percent by weight of the solid particles formed by this process passed through a 100-mesh screen. The particle-size distribution of the screened fraction of one run, as determined by sedimentation analysis, indicated that 73 percent by weight of the metal particles were finer than 2 microns in equivalent spherical diameter. The purity of the solid particles ranged as high as 98.9 percent by weight of free magnesium. The screened product was concentrated by means of a bowl-type centrifuge from 0.5 to more than 50 percent by weight solids content to form an extremely viscous, clay-like mass. By addition of a surface active agent, this viscous material was converted into a pumpable slurry fuel.

Discussion of parameters associated with the determination of arsenic by electrothermal atomic absorption spectrometry in slurried environmental samples.

PubMed

Vassileva, E; Baeten, H; Hoenig, M

2001-01-02

A slurry sampling-fast program procedure has been developed for the determination of arsenic in plants, soils and sediments by electrothermal atomic absorption spectrometry. Efficiencies of various single and mixed modifiers for thermal stabilization of arsenic and for a better removal of the matrix during pyrolysis step were compared. The influence of the slurry concentration, amounts of modifier and parameters of the pyrolysis step on the As integrated absorbance signals have been studied and a comparison between fast and conventional furnace programs was also made. The ultrasonic agitation of the slurry followed by a fast electrothermal program using an Ir/Mg modifier provides the most consistent performance in terms of precision and accuracy. The reliability of the whole procedure has been compared with results obtained after application of a wet digestion method with an HF step and validated by analyzing eleven certified reference materials. Arsenic detection and quantitation limits expressed on dry sample matter were about 30 and 100 micrograms kg-1, respectively.

(99)Tc(VII) Retardation, Reduction, and Redox Rate Scaling in Naturally Reduced Sediments.

PubMed

Liu, Yuanyuan; Liu, Chongxuan; Kukkadapu, Ravi K; McKinley, James P; Zachara, John; Plymale, Andrew E; Miller, Micah D; Varga, Tamas; Resch, Charles T

2015-11-17

An experimental and modeling study was conducted to investigate pertechnetate (Tc(VII)O4(-)) retardation, reduction, and rate scaling in three sediments from Ringold formation at U.S. Department of Energy's Hanford site, where (99)Tc is a major contaminant in groundwater. Tc(VII) was reduced in all the sediments in both batch reactors and diffusion columns, with a faster rate in a sediment containing a higher concentration of HCl-extractable Fe(II). Tc(VII) migration in the diffusion columns was reductively retarded with retardation degrees correlated with Tc(VII) reduction rates. The reduction rates were faster in the diffusion columns than those in the batch reactors, apparently influenced by the spatial distribution of redox-reactive minerals along transport paths that supplied Tc(VII). X-ray computed tomography and autoradiography were performed to identify the spatial locations of Tc(VII) reduction and transport paths in the sediments, and results generally confirmed the newly found behavior of reaction rate changes from batch to column. The results from this study implied that Tc(VII) migration can be reductively retarded at Hanford site with a retardation degree dependent on reactive Fe(II) content and its distribution in sediments. This study also demonstrated that an effective reaction rate may be faster in transport systems than that in well-mixed reactors.

Methods for the Calculation of Settling Tanks for Batch Experiments; METODOS DE CALCULO DE ESPESADORES POR ENSAYOS DISCONTINUOS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gasos, P.; Perea, C.P.; Jodra, L.G.

1957-01-01

>In order to calculate settling tanks, some tests on batch sedimentation were made, and with the data obtained the dimensions of the settling tank were found. The mechanism of sedimentation is first briefly described, and then the factors involved in the calculation of the dimensions and the sedimentation velocity are discussed. The Cloe and Clevenger method and the Kynch method were investigated experimentally and compared. The application of the calculations are illustrated. It is shown that the two methods gave markedly different results. (J.S.R.)

Fabrication of hydroxyapatite ceramics with controlled pore characteristics by slip casting.

PubMed

Yao, Xiumin; Tan, Shouhong; Jiang, Dongliang

2005-02-01

Porous hydroxyapatite (HAp) ceramics with controlled pore characteristics were fabricated using slip casting method by mixing PMMA with HAp powder. The optimum conditions of HAp slip for slip casting was achieved by employing various experimental techniques, zeta potential and sedimentation, as a function of pH of the slips in the pH range of 4-12. HAp suspensions displayed an absolute maximum in zeta potential values and a minimum in sedimentation height at pH 11.5. The optimal amount of dispersant for the HAp suspensions was found at 1.0 wt% according to the viscosity of 25 vol% HAp slurry. The rheological behaviour of HAp slurry displays a shear-thinning behavior without thixotropy, which is needed in slip casting processing. The pore characteristics of sintered porous hydroxyapatite bioceramics can be controlled by added PMMA particle size and volume. The obtained ceramics exhibit higher strength than those obtained by dry pressing.

BEHAVIOR OF MERCURY DURING DWPF CHEMICAL PROCESS CELL PROCESSING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zamecnik, J.; Koopman, D.

2012-04-09

The Defense Waste Processing Facility has experienced significant issues with the stripping and recovery of mercury in the Chemical Processing Cell (CPC). The stripping rate has been inconsistent, often resulting in extended processing times to remove mercury to the required endpoint concentration. The recovery of mercury in the Mercury Water Wash Tank has never been high, and has decreased significantly since the Mercury Water Wash Tank was replaced after the seventh batch of Sludge Batch 5. Since this time, essentially no recovery of mercury has been seen. Pertinent literature was reviewed, previous lab-scale data on mercury stripping and recovery wasmore » examined, and new lab-scale CPC Sludge Receipt and Adjustment Tank (SRAT) runs were conducted. For previous lab-scale data, many of the runs with sufficient mercury recovery data were examined to determine what factors affect the stripping and recovery of mercury and to improve closure of the mercury material balance. Ten new lab-scale SRAT runs (HG runs) were performed to examine the effects of acid stoichiometry, sludge solids concentration, antifoam concentration, form of mercury added to simulant, presence of a SRAT heel, operation of the SRAT condenser at higher than prototypic temperature, varying noble metals from none to very high concentrations, and higher agitation rate. Data from simulant runs from SB6, SB7a, glycolic/formic, and the HG tests showed that a significant amount of Hg metal was found on the vessel bottom at the end of tests. Material balance closure improved from 12-71% to 48-93% when this segregated Hg was considered. The amount of Hg segregated as elemental Hg on the vessel bottom was 4-77% of the amount added. The highest recovery of mercury in the offgas system generally correlated with the highest retention of Hg in the slurry. Low retention in the slurry (high segregation on the vessel bottom) resulted in low recovery in the offgas system. High agitation rates appear to result in lower retention of mercury in the slurry. Both recovery of mercury in the offgas system and removal (segregation + recovery) from the slurry correlate with slurry consistency. Higher slurry consistency results in better retention of Hg in the slurry (less segregation) and better recovery in the offgas system, but the relationships of recovery and retention with consistency are sludge dependent. Some correlation with slurry yield stress and acid stoichiometry was also found. Better retention of mercury in the slurry results in better recovery in the offgas system because the mercury in the slurry is stripped more easily than the segregated mercury at the bottom of the vessel. Although better retention gives better recovery, the time to reach a particular slurry mercury content (wt%) is longer than if the retention is poorer because the segregation is faster. The segregation of mercury is generally a faster process than stripping. The stripping factor (mass of water evaporated per mass of mercury stripped) of mercury at the start of boiling were found to be less than 1000 compared to the assumed design basis value of 750 (the theoretical factor is 250). However, within two hours, this value increased to at least 2000 lb water per lb Hg. For runs with higher mercury recovery in the offgas system, the stripping factor remained around 2000, but runs with low recovery had stripping factors of 4000 to 40,000. DWPF data shows similar trends with the stripping factor value increasing during boiling. These high values correspond to high segregation and low retention of mercury in the sludge. The stripping factor for a pure Hg metal bead in water was found to be about 10,000 lb/lb. About 10-36% of the total Hg evaporated in a SRAT cycle was refluxed back to the SRAT during formic acid addition and boiling. Mercury is dissolved as a result of nitric acid formation from absorption of NO{sub x}. The actual solubility of dissolved mercury in the acidic condensate is about 100 times higher than the actual concentrations measured. Mercury metal present in the MWWT from previous batches could be dissolved by this acidic condensate. The test of the effect of higher SRAT condenser temperature on recovery of mercury in the MWWT and offgas system was inconclusive. The recovery at higher temperature was lower than several low temperature runs, but about the same as other runs. Factors other than temperature appear to affect the mercury recovery. The presence of chloride and iodide in simulants resulted in the formation of mercurous chloride and mercurous iodide, respectively, in the offgas system. Actual waste data shows that the chloride content is much less than the simulant concentrations. Future simulant tests should minimize the addition of chloride. Similarly, iodine addition should be eliminated unless actual waste analyses show it to be present; currently, total iodine is not measured on actual waste samples.« less

Tank 40 Final Sludge Batch 8 Chemical Characterization Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, Christopher J.

2013-09-19

A sample of Sludge Batch 8 (SB8) was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). The SB8 WAPS sample was also analyzed for chemical composition, including noble metals, and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is currently being fed to the Defense Waste Processing Facility (DWPF) as SB8. At SRNL, the 3-L Tank 40 SB8 sample was transferred from the shipping container into amore » 4-L high density polyethylene bottle and solids were allowed to settle. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 553 g sub-sample was removed. This sub-sample was then utilized for all subsequent slurry sample preparations. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon(r) vessels and four with NaOH/Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Two Analytical Reference Glass - 1 (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 mL with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma - atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma - mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB8 supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH-/other base, total inorganic carbon/total organic carbon (TIC/TOC) analyses. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH-/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the Tank 40 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method developed by SRNL AD and previously described.« less

Tank 40 final sludge batch 9 chemical and fissile radionuclide characterization results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.; Kubilius, W. P.; Pareizs, J. M.

A sample of Sludge Batch (SB) 9 was pulled from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS)i. The SB9 WAPS sample was also analyzed for chemical composition, including noble metals, and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is fed to the Defense Waste Processing Facility (DWPF) as SB9. At the Savannah River National Laboratory (SRNL), the 3-L Tank 40 SB9 sample was transferred from the shippingmore » container into a 4-L high density polyethylene bottle and solids were allowed to settle. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 547 g sub-sample was removed. This sub-sample was then utilized for all subsequent slurry sample preparations. Eight separate aliquots of the slurry were digested, four with HNO3/HCl (aqua regiaii) in sealed Teflon® vessels and four with NaOH/Na2O2 (alkali or peroxide fusioniii) using Zr crucibles. Three Analytical Reference Glass – 1iv (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma – atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma – mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB9 supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH-/other base, total inorganic carbon/total organic carbon (TIC/TOC) analyses. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH-/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the SB9 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method developed by SRNL AD and previously described.v« less

A comparison of stable-isotope probing of DNA and phospholipid fatty acids to study prokaryotic functional diversity in sulfate-reducing marine sediment enrichment slurries.

PubMed

Webster, Gordon; Watt, Lynsey C; Rinna, Joachim; Fry, John C; Evershed, Richard P; Parkes, R John; Weightman, Andrew J

2006-09-01

Marine sediment slurries enriched for anaerobic, sulfate-reducing prokaryotic communities utilizing glucose and acetate were used to provide the first comparison between stable-isotope probing (SIP) of phospholipid fatty acids (PLFA) and DNA (16S rRNA and dsrA genes) biomarkers. Different 13C-labelled substrates (glucose, acetate and pyruvate) at low concentrations (100 microM) were used over a 7-day incubation to follow and identify carbon flow into different members of the community. Limited changes in total PLFA and bacterial 16S rRNA gene DGGE profiles over 7 days suggested the presence of a stable bacterial community. A broad range of PLFA were rapidly labelled (within 12 h) in the 13C-glucose slurry but this changed with time, suggesting the presence of an active glucose-utilizing population and later development of another population able to utilize glucose metabolites. The identity of the major glucose-utilizers was unclear as 13C-enriched PLFA were common (16:0, 16:1, 18:1omega7, highest incorporation) and there was little difference between 12C- and 13C-DNA 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) profiles. Seemingly glucose, a readily utilizable substrate, resulted in widespread incorporation consistent with the higher extent of 13C-incorporation (approximately 10 times) into PLFA compared with 13C-acetate or 13C-pyruvate. 13C-PLFA in the 13C-acetate and 13C-pyruvate slurries were similar to each other and to those that developed in the 13C-glucose slurry after 4 days. These were more diagnostic, with branched odd-chain fatty acids (i15:0, a15:0 and 15:1omega6) possibly indicating the presence of Desulfococcus or Desulfosarcina sulfate-reducing bacteria (SRB) and sequences related to these SRB were in the 13C-acetate-DNA dsrA gene library. The 13C-acetate-DNA 16S rRNA gene library also contained sequences closely related to SRB, but these were the acetate-utilizing Desulfobacter sp., as well as a broad range of uncultured Bacteria. In contrast, analysis of DGGE bands from 13C-DNA demonstrated that the candidate division JS1 and Firmicutes were actively assimilating 13C-acetate. Denaturing gradient gel electrophoresis also confirmed the presence of JS1 in the 13C-DNA from the 13C-glucose slurry. These results demonstrate that JS1, originally found in deep subsurface sediments, is more widely distributed in marine sediments and provides the first indication of its metabolism; incorporation of acetate and glucose (or glucose metabolites) under anaerobic, sulfate-reducing conditions. Here we demonstrate that PLFA- and DNA-SIP can be used together in a sedimentary system, with low concentrations of 13C-substrate and overlapping incubation times (up to 7 days) to provide complementary, although not identical, information on carbon flow and the identity of active members of an anaerobic prokaryotic community.

Extraction of organic contaminants from marine sediments and tissues using microwave energy.

PubMed

Jayaraman, S; Pruell, R J; McKinney, R

2001-07-01

In this study, we compared microwave solvent extraction (MSE) to conventional methods for extracting organic contaminants from marine sediments and tissues with high and varying moisture content. The organic contaminants measured were polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, and polycyclic aromatic hydrocarbons (PAHs). Initial experiments were conducted on dry standard reference materials (SRMs) and field collected marine sediments. Moisture content in samples greatly influenced the recovery of the analytes of interest. When wet sediments were included in a sample batch, low recoveries were often encountered in other samples in the batch, including the dry SRM. Experiments were conducted to test the effect of standardizing the moisture content in all samples in a batch prior to extraction. SRM1941a (marine sediment). SRM1974a (mussel tissue), as well as QA96SED6 (marine sediment), and QA96TIS7 (marine tissue), both from 1996 NIST Intercalibration Exercise were extracted using microwave and conventional methods. Moisture levels were adjusted in SRMs to match those of marine sediment and tissue samples before microwave extraction. The results demonstrated that it is crucial to standardize the moisture content in all samples, including dry reference material to ensure good recovery of organic contaminants. MSE yielded equivalent or superior recoveries compared to conventional methods for the majority of the compounds evaluated. The advantages of MSE over conventional methods are reduced solvent usage, higher sample throughput and the elimination of halogenated solvent usage.

Use of the [(14)C]leucine incorporation technique to measure bacterial production in river sediments and the epiphyton.

PubMed

Fischer, H; Pusch, M

1999-10-01

Bacterial production is a key parameter for the understanding of carbon cycling in aquatic ecosystems, yet it remains difficult to measure in many aquatic habitats. We therefore tested the applicability of the [(14)C]leucine incorporation technique for the measurement of bulk bacterial production in various habitats of a lowland river ecosystem. To evaluate the method, we determined (i) extraction efficiencies of bacterial protein from the sediments, (ii) substrate saturation of leucine in sediments, the biofilms on aquatic plants (epiphyton), and the pelagic zone, (iii) bacterial activities at different leucine concentrations, (iv) specificity of leucine uptake by bacteria, and (v) the effect of the incubation technique (perfused-core incubation versus slurry incubation) on leucine incorporation into protein. Bacterial protein was best extracted from sediments and precipitated by hot trichloroacetic acid treatment following ultrasonication. For epiphyton, an alkaline-extraction procedure was most efficient. Leucine incorporation saturation occurred at 1 microM in epiphyton and 100 nM in the pelagic zone. Saturation curves in sediments were difficult to model but showed the first level of leucine saturation at 50 microM. Increased uptake at higher leucine concentrations could be partly attributed to eukaryotes. Addition of micromolar concentrations of leucine did not enhance bacterial electron transport activity or DNA replication activity. Similar rates of leucine incorporation into protein calculated for whole sediment cores were observed after slurry and perfused-core incubations, but the rates exhibited strong vertical gradients after the core incubation. We conclude that the leucine incorporation method can measure bacterial production in a wide range of aquatic habitats, including fluvial sediments, if substrate saturation and isotope dilution are determined.

Use of the [14C]Leucine Incorporation Technique To Measure Bacterial Production in River Sediments and the Epiphyton

PubMed Central

Fischer, Helmut; Pusch, Martin

1999-01-01

Bacterial production is a key parameter for the understanding of carbon cycling in aquatic ecosystems, yet it remains difficult to measure in many aquatic habitats. We therefore tested the applicability of the [14C]leucine incorporation technique for the measurement of bulk bacterial production in various habitats of a lowland river ecosystem. To evaluate the method, we determined (i) extraction efficiencies of bacterial protein from the sediments, (ii) substrate saturation of leucine in sediments, the biofilms on aquatic plants (epiphyton), and the pelagic zone, (iii) bacterial activities at different leucine concentrations, (iv) specificity of leucine uptake by bacteria, and (v) the effect of the incubation technique (perfused-core incubation versus slurry incubation) on leucine incorporation into protein. Bacterial protein was best extracted from sediments and precipitated by hot trichloroacetic acid treatment following ultrasonication. For epiphyton, an alkaline-extraction procedure was most efficient. Leucine incorporation saturation occurred at 1 μM in epiphyton and 100 nM in the pelagic zone. Saturation curves in sediments were difficult to model but showed the first level of leucine saturation at 50 μM. Increased uptake at higher leucine concentrations could be partly attributed to eukaryotes. Addition of micromolar concentrations of leucine did not enhance bacterial electron transport activity or DNA replication activity. Similar rates of leucine incorporation into protein calculated for whole sediment cores were observed after slurry and perfused-core incubations, but the rates exhibited strong vertical gradients after the core incubation. We conclude that the leucine incorporation method can measure bacterial production in a wide range of aquatic habitats, including fluvial sediments, if substrate saturation and isotope dilution are determined. PMID:10508068

ADSORPTION MECHANISMS AND TRANSPORT BEHAVIOR BETWEEN SELENATE AND SELENITE ON DIFFERENT SORBENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snyder, Michelle MV; Um, Wooyong

Adsorption of different oxidation species of selenium (Se), selenate (SeO42-) and selenite (SeO32-), with varying pHs (2 - 10) and ionic strengths (I = 0.01 M, 0.1 M and 1.0 M NaNO3) was measured on quartz, aluminum oxide, and synthetic iron oxide (ferrihydrite) using batch reactors to obtain a more detailed understanding of the adsorption mechanisms (e.g., inner- and outer-sphere complex). In addition to the batch experiments with single minerals contained in native Hanford Site sediment, additional batch adsorption studies were conducted with native Hanford Site sediment and groundwater as a function of 1) total Se concentration (from 0.01 tomore » 10 mg L-1) and 2) soil to solution ratios (1:20 and 1:2 grams per mL). Results from these batch studies were compared to a set of saturated column experiments that were conducted with natural Hanford sediment and groundwater spiked with either selenite or selenate to observe the transport behavior of these species. Both batch and column results indicated that selenite adsorption was consistently higher than that of selenate in all experimental conditions used. These different adsorption mechanisms between selenite and selenate result in the varying mobility of Se in the subsurface environment and explain the dependence on the oxidation species.« less

Removal of endosulfan and methoxychlor from water on carbon slurry.

PubMed

Gupta, Vinod K; Ali, Imran

2008-02-01

A carbon slurry, produced in generators of fuel-oil-based industrial generators was converted into an effective and efficient adsorbent for the removal of endosulfan and methoxychlor from aqueous solution. The adsorbent was chemically treated, activated, characterized, and used for the adsorption of endosulfan and methoxychlor pesticides. The maximum adsorption was found at 90 min, 6.5 pH, 0.025 g/L dose, and 25 degrees C temperature. Langmuir and Freundlich adsorption models were applied to analyze adsorption data, and the former was found applicable to this adsorption system in terms of relatively high regression values. The thermodynamic aspect of the process was also investigated by evaluating certain important parameters (enthalpy, free energy, and entropy of system). Kinetics of adsorption was found to follow the pseudo second order rate equation. The diffusion of pesticides into carbon slurry pores was suggested to be the rate controlling step by applying Bangham's equation. Adsorption on a column was also investigated in a continuous flow system. Adsorption efficiencies of endosulfan and methoxychlor were 34.11 and 36.06 mg/g in batch processes and 32.62 and 33.52 mg/g in column operations, respectively.

Evaluation of Inorganic/Organic Separators

NASA Technical Reports Server (NTRS)

Donnel, C. P., III

1976-01-01

Thirty-six (36) experimental 40AH sealed silver-zinc cells were constructed during phase I of this two (2) phase program. These cells were divided into six (6) groups of six (6) cells each. Each group of six (6) cells was evenly divided into two batches of three (3) cells each. Groups 1 through 4 each featured a different inorganic filler material in the slurry used to coat the separator substrate. Groups 5 and 6 featured an alternate method of separator bag construction. With the exception of the various separator materials, the parts and processes used to produce these thirty-six (36) cells were the same as those used to make the HR40-7 cell. The two (2) batches of cells in each cell group differed only in the lots of solutions and other separator slurry components used. Each cell was given two formation charge/discharge cycles prior to being shipped to NASA Lewis Research Center. Phase II of the program consisted of constructing another thirty-six (36) 40AH experimental cells in six (6) groups of six (6) cells each. Each group was distinguished by the type of precoated separator material used to fabricate separator bags. A new method of separator bag construction was used in this phase of the program. These cells were given two (2) formation cycles and shipped to NASA Lewis Research Center.

DECHLORINATION OF POLYCHLORINATED BIPHENYLS IN SEDIMENT SLURRIES BY PALLADIUM MODIFIED ZEROVALENT IRON

EPA Science Inventory

Polychlorinated biphenyls (PCBs) are one group of persistent organic pollutants (POPs) of international concern because of global distribution, persistence, and toxicity. Removal of these compounds from the environment presents a very tough challenge because they are highly hydro...

BIDEGRADATION FO SORBED FLUORENE IN SEDIMENT SLURRIES. (R825513C020)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Study on the antiseepage mechanism of the PBFC slurry for landfill site

NASA Astrophysics Data System (ADS)

Dai, Guozhong; Shi, Weicheng; Jiang, Xiaoshu; Shi, Guicai; Zhang, Yaxing

2017-07-01

In order to develop a kind of slurry with low permeability which has some adsorption and retardation to the pollutants in leachate to be used in antiseepage engineering of leachate for landfill site, experiments based on orthogonal method were performed. The optimal PBFC slurry was selected: bentonite 18-26%, cement 16-24%, fly ash 18-20%, TOJ800-10 water reducing agent 0.01-0.03%, polyvinyl alcohol 0.2-0.8%, sodium carbonate 0.8-1.5% and water 680-780/1000 mL seriflus. The material has good groutability and a concretion stone ratio which is greater than 99.6%. The coefficient of permeability of 28-day concretion body is 0.53 × 10-8-1.86 × 10-8 cm/s and the compressive strength is 0.64-1.04 MPa. The slurry has good adsorption and retardation properties. The block rate of NH4-N and phosphorus reached 98.28%, and the block rate of CODCr and BOD5 reached 85.67%. The block rate of Hg, Pb and other heavy metal ions reached 99.8%. The PBFC slurry improved the retardation capability of the pollutants of the leachate at the landfill site by its infiltration sedimentation and adsorption fixation.

Solids, organic load and nutrient concentration reductions in swine waste slurry using a polyacrylamide (PAM)-aided solids flocculation treatment.

PubMed

Walker, Paul; Kelley, Tim

2003-11-01

Increased swine production results in concentration of wastes generated within a limited geographical area, which may lead to land application rates exceeding the local or regional assimilatory capacity. This may result in pollutant transfer through surface water or soil-groundwater systems, environmental degradation, and/or odor concerns. Existing swine waste pit storage and lagoon treatment technologies may be inadequate to store or treat waste prior to land application without these concerns resulting. Efficient swine waste solids separation may reduce environmental health concerns and generate a value-added bioresource (solids). This study evaluated the efficiency of a polyacrylamide (PAM) flocculant-aided solids separation treatment to reduce pollution indicator concentrations in raw (untreated) swine waste slurry. Swine waste slurry solids separation efficiency through gravity settling (sedimentation) was evaluated before and after the addition of a proprietary polymeric (PAM) flocculant. Results indicated that polymer amendments at concentrations of 62.5-750 mg/l improved slurry solids separation efficiency and significantly reduced concentrations of other associated aquatic pollution indicators in a majority of analyses conducted (33 of 50 total analyses conducted). Results also suggested that PAM-aided solids separation from swine waste slurry might facilitate further treatment and/or disposal and therefore reduce associated environmental degradation potential.

Characterization of Long-term Stability of Sodium Dithionite for Evaluation of its Potential Utility for Cr(VI) Remediation at Los Alamos National Laboratory

NASA Astrophysics Data System (ADS)

Telfeyan, K.; Migdissov, A. A.; Reimus, P. W.

2017-12-01

Sodium dithionite (Na2S2O4) has proven to be an effective remediation agent in aquifers contaminated with Cr(VI). S2O42- rapidly reduces the Fe(III) in aquifer sediments to Fe(II), which then reduces aqueous Cr(VI) to insoluble Cr(III). Previous work demonstrated that the reaction products from this treatment have no long-lasting undesirable effects. However, current literature regarding the stability of dithionite in aqueous solution and its decomposition products, which are important for developing a practical treatment approach, is sparse and inconsistent. Furthermore, S2O42- treatment effectiveness depends on site-specific geochemical and hydrological conditions, so experiments using site-specific materials are necessary to develop an optimal treatment strategy. In this study, we conducted (1) batch aqueous-phase-only experiments aimed at elucidating dithionite lifetimes and decomposition products as a function of dithionite concentration and pH, (2) batch experiments at the most practical pH for a field deployment, with use of four different representations of site aquifer sediments to evaluate dithionite reaction rates in the presence of the sediments and to determine the reduction capacity of the treated sediments, and (3) column experiments to represent a field-scale deployment of dithionite and determine the Cr(VI) reduction capacity of the reduced sediments. The aqueous-phase-only batch experiments verified the presence of S2O42- in aqueous anoxic solution beyond 100 days at alkaline pH. Each sampling interval also recorded the concentration of decomposition products, which enabled the derivation of a possible hydrolysis/decomposition reaction. In the batch experiments with sediments, dithionite reacted more rapidly than in blank solutions, but measurable concentrations remained for over a month. Cr was then added to the reactors to determine the efficacy of treatment. Depending on the sediment type and concentration of dithionite, the treated sediments were able to remove between 100 and 1000 µg Cr per gram of sediment. Column experiments then determined that the dithionite treatment of aquifer sediments could treat over 30 pore volumes of contaminated water (900 ppb Cr) prior to any breakthrough of Cr, suggesting that S2O42- should be an effective treatment agent at this site.

Design and development of a prototype wet oxidation system for the reclamation of water and the disposition of waste residues onboard space vehicles

NASA Technical Reports Server (NTRS)

Jagow, R. B.

1972-01-01

Laboratory investigations to define optimum process conditions for oxidation of fecal/urine slurries were conducted in a one-liter batch reactor. The results of these tests formed the basis for the design, fabrication, and testing of an initial prototype system, including a 100-hour design verification test. Areas of further development were identified during this test. Development of a high pressure slurry pump, materials corrosion studies, oxygen supply trade studies, comparison of salt removal water recovery devices, ammonia removal investigation, development of a solids grinder, reactor design studies and bearing life tests, and development of shutoff valves and a back pressure regulator were undertaken. The development work has progressed to the point where a prototype system suitable for manned chamber testing can be fabricated and tested with a high degree of confidence of success.

Gypsum crystal size distribution in four continuous flow stirred slurry boric acid reactors in series compared with the batch

NASA Astrophysics Data System (ADS)

Çakal, G. Ö.; Eroğlu, İ.; Özkar, S.

2006-04-01

Colemanite, one of the important boron minerals, is dissolved in aqueous sulfuric acid to produce boric acid. In this reaction, gypsum is obtained as a by-product. Gypsum crystals are in the shape of thin needles. These crystals should be grown to an easily filterable size in order to increase the production yield and purity of boric acid. In this paper, the particle size distributions and the volume-weighted mean diameters of the gypsum crystals obtained in batch and continuous flow systems were compared. Experiments in both batch and continuous reactors were performed at a temperature of 85 °C, a stirring rate of 400 rpm, and the inlet CaO to SO42- molar ratio of 1.0 using colemanite mineral in particle size smaller than 150 μm. The average diameter of the gypsum crystals obtained at 3.5 h from the batch reactor was found to be 37-41 μm. This value for the continuous system at steady state was observed to change between 44-163 μm. The particle size of the gypsum crystals was found to increase with the residence time of the solid in the continuous system.

Two-liquid-phase slurry bioreactors to enhance the degradation of high-molecular-weight polycyclic aromatic hydrocarbons in soil.

PubMed

Villemur, R; Déziel, E; Benachenhou, A; Marcoux, J; Gauthier, E; Lépine, F; Beaudet, R; Comeau, Y

2000-01-01

High-molecular-weight (HMW) polycyclic aromatic hydrocarbons (PAHs) are pollutants that persist in the environment due to their low solubility in water and their sequestration by soil and sediments. The addition of a water-immiscible, nonbiodegradable, and biocompatible liquid, silicone oil, to a soil slurry was studied to promote the desorption of PAHs from soil and to increase their bioavailability. First, the transfer into silicone oil of phenanthrene, pyrene, chrysene, and benzo[a]pyrene added to a sterilized soil (sandy soil with 0.65% total volatile solids) was measured for 4 days in three two-liquid-phase (TLP) slurry systems each containing 30% (w/v) soil but different volumes of silicone oil (2.5%, 7.5%, and 15% [v/v]). Except for chrysene, a high percentage of these PAHs was transferred from soil to silicone oil in the TLP slurry system containing 15% silicone oil. Rapid PAH transfer occurred during the first 8 h, probably resulting from the extraction of nonsolubilized and of poorly sorbed PAHs. This was followed by a period in which a slower but constant transfer occurred, suggesting extraction of more tightly bound PAHs. Second, a HMW PAH-degrading consortium was enriched in a TLP slurry system with a microbial population isolated from a creosote-contaminated soil. This consortium was then added to three other TLP slurry systems each containing 30% (w/v) sterilized soil that had been artificially contaminated with pyrene, chrysene, and benzo[a]pyrene, but different volumes of silicone oil (10%, 20%, and 30% [v/v]). The resulting TLP slurry bioreactors were much more efficient than the control slurry bioreactor containing the same contaminated soil but no oil phase. In the TLP slurry bioreactor containing 30% silicone oil, the rate of pyrene degradation was 19 mg L(-)(1) day(-)(1) and no pyrene was detected after 4 days. The degradation rates of chrysene and benzo[a]pyrene in the 30% TLP slurry bioreactor were, respectively, 3.5 and 0.94 mg L(-)(1) day(-)(1). Low degradation of pyrene and no significant degradation of chrysene and benzo[a]pyrene occurred in the slurry bioreactor. This is the first report in which a TLP system was combined with a slurry system to improve the biodegradation of PAHs in soil.

Methane oxidation and molecular characterization of methanotrophs from a former mercury mine impoundment

USGS Publications Warehouse

Baesman, Shaun; Miller, Laurence G.; Wei, Jeremy H.; Cho, Yirang; Matys, Emily D.; Summons, Roger E.; Welander, Paula V.; Oremland, Ronald S.

2015-01-01

The Herman Pit, once a mercury mine, is an impoundment located in an active geothermal area. Its acidic waters are permeated by hundreds of gas seeps. One seep was sampled and found to be composed of mostly CO2 with some CH4 present. The δ13CH4 value suggested a complex origin for the methane: i.e., a thermogenic component plus a biological methanogenic portion. The relatively 12C-enriched CO2 suggested a reworking of the ebullitive methane by methanotrophic bacteria. Therefore, we tested bottom sediments for their ability to consume methane by conducting aerobic incubations of slurried materials. Methane was removed from the headspace of live slurries, and subsequent additions of methane resulted in faster removal rates. This activity could be transferred to an artificial, acidic medium, indicating the presence of acidophilic or acid-tolerant methanotrophs, the latter reinforced by the observation of maximum activity at pH = 4.5 with incubated slurries. A successful extraction of sterol and hopanoid lipids characteristic of methanotrophs was achieved, and their abundances greatly increased with increased sediment methane consumption. DNA extracted from methane-oxidizing enrichment cultures was amplified and sequenced for pmoA genes that aligned with methanotrophic members of the Gammaproteobacteria. An enrichment culture was established that grew in an acidic (pH 4.5) medium via methane oxidation.

Catalytic degradation of the soil fumigant 1,3-dichloropropene in aqueous biochar slurry.

PubMed

Qin, Jiaolong; Cheng, Yuxiao; Sun, Mingxing; Yan, Lili; Shen, Guoqing

2016-11-01

Biochar has been explored as a cost-effective sorbent of contaminants, such as soil fumigant. However, contaminant-loaded biochar probably becomes a source of secondary air pollution. In this study, biochars developed from cow manure and rice husk at 300°C or 700°C were used to investigate the catalytic degradation of the soil fumigant 1,3-dichloropropene (1,3-D) in aqueous biochar slurry. Results showed that the adsorption of 1,3-D on the biochars was influenced by Langmuir surface monolayer adsorption. The maximum adsorption capacity of cow manure was greater than that of rice husk at the same pyrolysis temperature. Batch experiments revealed that 1,3-D degradation was improved in aqueous biochar slurry. The most rapid 1,3-D degradation occurred on cow manure-derived biochar produced at 300°C (C-300), with t1/2=3.47days. The degradation efficiency of 1,3-D on C-300 was 95.52%. Environmentally persistent free radicals (EPFRs) in biochars were detected via electron paramagnetic resonance (EPR) techniques. Dissolved organic matter (DOM) and hydroxyl radical (·OH) in biochars were detected by using a fluorescence spectrophotometer coupled with a terephthalic acid trapping method. The improvement of 1,3-D degradation efficiency may be attributed to EPFRs and DOM in aqueous biochar slurry. Our results may pose implications in the development of effective reduction strategies for soil fumigant emission with biochar. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance and membrane fouling of a step-fed submerged membrane sequencing batch reactor treating swine biogas digestion slurry.

PubMed

Han, Zhiying; Chen, Shixia; Lin, Xiaochang; Yu, Hongjun; Duan, Li'an; Ye, Zhangying; Jia, Yanbo; Zhu, Songming; Liu, Dezhao

2018-01-02

To identify the performance of step-fed submerged membrane sequencing batch reactor (SMSBR) treating swine biogas digestion slurry and to explore the correlation between microbial metabolites and membrane fouling within this novel reactor, a lab-scale step-fed SMSBR was operated under nitrogen loading rate of 0.026, 0.052 and 0.062 g NH 4 + -N (gVSS·d) -1 . Results show that the total removal efficiencies for NH 4 + -N, total nitrogen and chemical oxygen demand in the reactor (>94%, >89% and >97%, respectively) were high during the whole experiment. However, the cycle removal efficiency of NH 4 + -N decreased significantly when the nitrogen loading rate was increased to 0.062 g NH 4 + -N (gVSS·d) -1 . The total removal efficiency of total phosphorus in the step-fed SMSBR was generally higher than 75%, though large fluctuations were observed during the experiments. In addition, the concentrations of microbial metabolites, i.e., soluble microbial products (SMP) and extracellular polymeric substances (EPS) from activated sludge increased as nitrogen loading rate increased, both showing quadratic equation correlations with viscosity of the mixed liquid in the step-fed SMSBR (both R 2 > 0.90). EPS content was higher than SMP content, while protein (PN) was detected as the main component in both SMP and EPS. EPS PN was found to be well correlated with transmembrane pressure, membrane flux and the total membrane fouling resistance. Furthermore, the three-dimensional excitation-emission matrix fluorescence spectroscopy results suggested the tryptophan-like protein as one of the main contributors to the membrane fouling. Overall, this study showed that the step-fed SMSBR could be used to treat swine digestion slurry at nitrogen loading rate of 0.052 g NH 4 + -N (gVSS·d) -1 , and the control strategy of membrane fouling should be developed based on reducing the tryptophan-like PN in EPS.

The influence of different geotechnically relevant amendments on the reductive degradation of TCE by nZVI

NASA Astrophysics Data System (ADS)

Freitag, Peter; Schöftner, Philipp; Waldner, Georg; Reichenauer, Thomas G.; Nickel, Claudia; Spitz, Marcus; Dietzel, Martin

2014-05-01

Trichloroethylene (TCE) was widely used as a cleaning and degreasing agent. Companies needing these agents were often situated in or close to built up areas, so spillage led to contaminated sites which now can only be remediated using in situ techniques. The situation is compounded by the fact that TCE tends to seep through ground water bodies forming pools at the bottom of the aquifer. When reacting with TCE, nanoscale zero valent iron (nZVI) is known to reduce it into non-toxic substances. The difficulty is to bring it in contact with the pollutant. Attempts using passive insertion into the groundwater via wells yielded mixed results. Reasons for this are that ZVI tends to coagulate, to sediment and to adsorb on the matrix of the aquifer. Also, in inhomogeneous aquifers a passive application of nZVI can be difficult and might not bring the desired results, due to existence of preferential flow paths. A possible solution to this problem is the physical in situ mixing of ZVI into the contaminant source. This can, in principle, be done by adapting jet grouting - a method that uses a high pressure slurry jet, consisting of water and geotechnical additives ("binders"), to mix and compact zones ("columns") in soil. These columns are commonly used to solve foundation problems but can also be used to solve the problem of delivering nZVI to TCE source zones. This paper examines the influence binders have on the degradation reaction between TCE and nZVI. The necessity of these binders is explained by the fact that the subsoil structure is rearranged during the jetting process leading to subsidence on the surface. These subsidences could result in damage to neighbouring structures. A series of batch experiments was conducted in this study. Contaminated groundwater was brought into contact with samples of slurries commonly used in geotechnical applications. We tested the effects of concresole, bentonite, zeolithe, fly ash, slag sand and cement on the kinetics of TCE degradation by nZVI. The degradation of TCE was measured using GC Headspace samples. Furthermore, additional experiments were conducted to investigate the interaction between binders and TCE as well as binders and nZVI. The results of these experiments led to the conclusion that jet grouting could be well suited for the delivery of nZVI to TCE contaminated source zones. Currently, soil column experiments and large-scale experiments in test facilities are performed to confirm the batch testing results.

Operational Test Report (OTR): On-Site Degradation of Oily Sludge in a Tenthousand Gallon Sequencing Batch Reactor at Navsta Pearl Harbor, HI

DTIC Science & Technology

2003-11-01

treated anaerobically . To accommodate the longer residence times needed to treat waste anaerobically , the capacity is often much larger than a...the receiving tank (T1), where it is diluted and run through a trash pump (P1) to produce a homogenous slurry. 3 Figure 1. Sequencing...blower provides air to the reactor and receiving tank. The trash pump is also used to transfer sludge to the reactor and to recirculate sludge in

Use of Activated Carbon to Control Volatilization of Organic Contaminants from the Indiana Harbor Confined Disposal Facility

DTIC Science & Technology

2012-09-01

PAHs (17 priority pollutant PAHs) were extracted from sediment by USEPA SW-846 Method 3545 and analyzed by gas chromatography /mass spectrometry...slurry at concentrations of 0.025, 0.05, and 0.10 g/L. The carbon- sediment mixture was equilibrated by tumbling in zero headspace jars for 15 minutes...cooled injection gas chromatography injection system at -40 °C. Once the analytes were transferred, the injection port was heated to 240 °C and

Selective removal of organic contaminants from sediments: A methodology for toxicity identification evaluations (TIEs)

USGS Publications Warehouse

Lebo, J.A.; Huckins, J.N.; Petty, J.D.; Ho, K.T.; Stern, E.A.

2000-01-01

Aqueous slurries of a test sediment spiked with dibenz[a,h]anthracene, 2,4,5,2′,4′,5′-hexachlorobiphenyl, p,p′-DDE, or phenanthrene were subjected to decontamination experimentation. The spiked sediments were agitated at elevated temperatures for at least 96 h in the presence of either of the two contaminant-absorbing media: clusters of polyethylene membrane or lipid-containing semipermeable membrane devices (SPMDs). The effects of treatment temperature and surface area of media on the removal of contaminants were explored. This work is part of a larger methodology for whole-sediment toxicity identification evaluation (TIE). A method is being sought that is capable of detoxifying sediments with respect to organic contaminants while leaving toxicity attributable to inorganic contaminants unaffected.

Settling characteristics of fine-grained sediments used in Louisiana coastal land building and restoration projects

NASA Astrophysics Data System (ADS)

Ghose Hajra, M.

2016-02-01

Coastal property development, sea level rise, geologic subsidence, loss of barrier islands, increasing number and intensity of coastal storms and other factors have resulted in water quality degradation, wetlands loss, reduced storm and surge protection, ground settlement, and other challenges in coastal areas throughout the world. One of the goals towards reestablishing a healthy coastal ecosystem is to rebuild wetlands with river diversion or sediment conveyance projects that optimally manage and allocate sediments, minimally impact native flora and fauna, and positively affect the water quality. Engineering properties and material characteristics of the dredged material and foundation soils are input parameters in several mathematical models used to predict the long term behavior of the dredged material and foundation soil. Therefore, proper characterization of the dredged material and foundation soils is of utmost importance in the correct design of a coastal restoration and land reclamation project. The sedimentation and consolidation characteristics of the dredged material as well as their effects on the time rate of settlement of the suspended solid particles and underlying foundation soil depend, among other factors, on the (a) grain size distribution of the dredged material, (b) salinity (fresh, brackish, or saltwater environment) of the composite slurry, and (c) concentration of the solid particles in the slurry. This paper will present the results from column settling tests and self-weight consolidation tests performed on dredged samples obtained from actual restoration projects in Louisiana. The effects of salinity, grain size distribution, and initial particle concentration on the sedimentation and consolidation parameters of the dredged material will also be discussed.

Cesium migration in saturated silica sand and Hanford sediments as impacted by ionic strength.

PubMed

Flury, Markus; Czigány, Szabolcs; Chen, Gang; Harsh, James B

2004-07-01

Large amounts of 137Cs have been accidentally released to the subsurface from the Hanford nuclear site in the state of Washington, USA. The cesium-containing liquids varied in ionic strengths, and often had high electrolyte contents, mainly in the form of NaNO3 and NaOH, reaching concentrations up to several moles per liter. In this study, we investigated the effect of ionic strengths on Cs migration through two types of porous media: silica sand and Hanford sediments. Cesium sorption and transport was studied in 1, 10, 100, and 1000 mM NaCl electrolyte solutions at pH 10. Sorption isotherms were constructed from batch equilibrium experiments and the batch-derived sorption parameters were compared with column breakthrough curves. Column transport experiments were analyzed with a two-site equilibrium-nonequilibrium model. Cesium sorption to the silica sand in batch experiments showed a linear sorption isotherm for all ionic strengths, which matched well with the results from the column experiments at 100 and 1000 mM ionic strength; however, the column experiments at 1 and 10 mM ionic strength indicated a nonlinear sorption behavior of Cs to the silica sand. Transport through silica sand occurred under one-site sorption and equilibrium conditions. Cesium sorption to Hanford sediments in both batch and column experiments was best described with a nonlinear Freundlich isotherm. The column experiments indicated that Cs transport in Hanford sediments occurred under two-site equilibrium and nonequilibrium sorption. The effect of ionic strength on Cs transport was much more pronounced in Hanford sediments than in silica sands. Effective retardation factors of Cs during transport through Hanford sediments were reduced by a factor of 10 when the ionic strength increased from 100 to 1000 mM; for silica sand, the effective retardation was reduced by a factor of 10 when ionic strength increased from 1 to 1000 mM. A two order of magnitude change in ionic strength was needed in the silica sand to observe the same change in Cs retardation as in Hanford sediments. Copyright 2003 Elsevier B.V.

Mn-oxidizing Bacteria in Oak Ridge, TN and the Potential for Mercury Remediation

NASA Astrophysics Data System (ADS)

Wright, K. L.; McNeal, K. S.; Han, F. X.

2012-12-01

East Fork Poplar Creek (EFPC) in Oak Ridge, TN was highly contaminated with elemental mercury in the 1950 and 1960. The area is still experiencing the effects of mercury contamination, and researchers are searching for ways to remediate the EFPC. One possible mechanism for bioremediation is the use of biogenic Mn oxides to remove heavy metals from water systems. Six native Pseudomonas bacteria species were isolated from the EFPC in order to examine biogenic Mn oxides production and bioremediation of Oak Ridge slurries. To investigate the biochemical interactions of Pseudomonas and the native microbial communities with Hg, Mn, Fe, S, six different slurry treatment groups were compared using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and cold vapor atomic absorption spectrometry (CVAAS). Oak Ridge slurries were autoclaved to inhibit microbial growth (group 1), autoclaved and amended with HgS (group 2), autoclaved and amended with Pseudomonas isolates and additional HgS (group 3), untreated slurry (group 4), normal slurry amended with HgS (group 5), and normal slurry amended with Pseudomonas isolates and additional HgS (group 6). The comparison of the autoclaved groups with the counterpart untreated and normal Oak Ridge slurries highlighted important microbial interactions. Also, the Pseudomonas isolates were grown separately in a MnSO4 media, and the individual bacteria were monitored for Mn-oxidization using ICP-AES and transmission electron microscopy (TEM). In the slurry sediments, the Pseudomonas isolates did produce Mn oxides which bound to mercury, and mercury bound to organic matter significantly decreased. However, after a significant decrease of dissolved mercury in the water, dissolved mercury was cycled back into the water system on day 10 of the study. Additionally, two individual native Oak Ridge Pseudomonas isolates demonstrated Mn-oxidization. Biogenic Mn oxides have the potential to decrease mercury cycling, however there is need for more in depth and long-term studies to confirm their sustained use as Hg bioremediators.

Can interpreting sediment toxicity tests a mega sites benefit from novel approaches to normalization to address batching of tests?

EPA Science Inventory

Sediment toxicity tests are a key tool used in Ecological Risk Assessments for contaminated sediment sites. Interpreting test results and defining toxicity is often a challenge. This is particularly true at mega sites where the testing regime is large, and by necessity performed ...

30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Secretary. (c) After each examination and instrumentation monitoring referred to in paragraphs (a) and (b... instrumentation monitoring shall promptly record the results of such examination or instrumentation monitoring in... instrumentation monitoring reports recorded in accordance with paragraph (c) of this section shall include a...

30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Secretary. (c) After each examination and instrumentation monitoring referred to in paragraphs (a) and (b... instrumentation monitoring shall promptly record the results of such examination or instrumentation monitoring in... instrumentation monitoring reports recorded in accordance with paragraph (c) of this section shall include a...

30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Secretary. (c) After each examination and instrumentation monitoring referred to in paragraphs (a) and (b... instrumentation monitoring shall promptly record the results of such examination or instrumentation monitoring in... instrumentation monitoring reports recorded in accordance with paragraph (c) of this section shall include a...

30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Secretary. (c) After each examination and instrumentation monitoring referred to in paragraphs (a) and (b... instrumentation monitoring shall promptly record the results of such examination or instrumentation monitoring in... instrumentation monitoring reports recorded in accordance with paragraph (c) of this section shall include a...

30 CFR 77.216-3 - Water, sediment, or slurry impoundments and impounding structures; inspection requirements...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Secretary. (c) After each examination and instrumentation monitoring referred to in paragraphs (a) and (b... instrumentation monitoring shall promptly record the results of such examination or instrumentation monitoring in... instrumentation monitoring reports recorded in accordance with paragraph (c) of this section shall include a...

Setback distance requirements for removal of swine slurry constituents in runoff

USDA-ARS?s Scientific Manuscript database

The establishment of vegetative filter strips at the bottom of a hillslope has been shown to substantially reduce nutrients and sediment in runoff. The use of setback distances on cropland areas could serve a similar function. However, there is little information available to help identify setback ...

Accelerated Rates of Nitrogen Cycling and N2O Production in Salt Marsh Sediments due to Long-Term Fertilization

NASA Astrophysics Data System (ADS)

Peng, X.; Ji, Q.; Angell, J.; Kearns, P.; Bowen, J. L.; Ward, B. B.

2014-12-01

Intensified sedimentary production of nitrous oxide (N2O), one of the most potent greenhouse gases, is one of the many possible environmental consequences of elevated nitrogen (N) loading into estuarine ecosystems. This study investigates the response to over 40 years of fertilization of nitrogen removal processes in the sediments of the Great Sippewissett Marsh in Falmouth, MA. Sediment slurries were incubated (1.5 hr) with trace amounts (< 10% of ambient concentration) of 15NH4+ + 14NO3- or 15NO3- + 14NH4+. An additional parallel incubation with 15NH4+ + 14NO3- and 1 mM of allylthiourea (ATU) was included to measure rates of anaerobic ammonia oxidation (anammox). Well-homogenized slurries filled about 10% of the volume in the gas-tight incubation vials, and the rest of the volume was replaced with an O2/He (20%/80%) mixture. The production of 29N2, 44N2O and 45N2O were determined using isotope ratio mass spectrometry. The rate of total N2O production in fertilized sediments (0.89 nmol hr-1 g-1 wet weight) was 30-fold higher than in unfertilized sediments. The ratio of N2O to N2 production was also significantly higher in fertilized sediments (2.9%) than in unfertilized sediments (1.2%). This highlights the disproportionally large effect of long-term fertilization on N2O production in salt marsh sediments. The reduced oxygen level and higher ammonium concentrations in situ probably contributed to the significant rise in N2O production as a result of long-term fertilization. When detected, anammox and coupled nitrification-denitrification accounted for 10% and 14% of the total N2 production in fertilized sediments (30.5 nmol hr-1 g-1 wet weight), respectively, whereas neither was detected in unfertilized sediments. Thus these experiments indicate that N loading has important effects on multiple N cycle processes that result in N loss and N2O production.

Butyltin sorption onto freshwater sediments: from batch experiments to the field values

NASA Astrophysics Data System (ADS)

Bancon-Montingy, C.; Aubert, G.; Chahinian, N.; Meyer, J.; Brunel, V.; Tournoud, M. G.

2009-04-01

Butyltins, and most particularly TBT were widely used by the industry in the 1970s and 1980s, namely as anti-fouling paints on ships. Although banned since 2003 in Europe, surveys still point out the presence of these compounds both in coastal and terrestrial environments. The resilience of organotin (OT) compounds can be explained by their high adsorption capacity. OTs can bond easily to particulate matter and "migrate" from the water column unto the sediments where their half-life can extend to a few decades. Consequently sediments can become important organotin stores and release OT compounds during dredging operations, storms, tides or floods. Studies on OT behavior in freshwater environments, mainly sediments, are scarce in the literature compared with marine sediments. However, it is known that sorption behaviour of organotin compounds on sediments is governed by the constituents of sediments, and the composition of interstitial water in the sediments and overlying water, i.e. grain size distribution, clay minerals, organic matter, iron, aluminium (hydr)oxides and carbonate in the sediments; salinity, ionic composition, and pH of interstitial water in the sediments and overlying water. The main objective of this work is to assess butyltin adsorption into the sediments of an intermittent river located in southern France: The Vène. Sediments were collected during high and low flow conditions and batch experiments were set up using "natural" and "crushed" sediments to assess the adsorption kinetics. Classical batch experiments and GC-ICP-MS analysis were carried out to measure the distribution coefficient (Kd). The influence of organic substances on sorption processes for organotin species was studied and the role of grain size distribution assessed by comparing natural and crushed sediments. The results indicated that organotin compounds are sorbed easily and quickly on freshwater sediments. The adsorption isotherm for butyltins follows the Freundlich equation which is used to describe the adsorption behaviour of non-polar organic matters. This is due to their organic substituent groups. The presence of organic matter modifies the sorption process: less OT is adsorbed onto the sediments. This leads to increased OT concentrations in solution and consequently a higher probability for assimilation by freshwater organisms. The comparison of our results to those reported in the literature for marine environments could not be carried out because of the wide differences in salinity and grain size distribution between the two environments.

MODELING HEXAVALENT CHROMIUM REDUCTION IN GROUND- WATER IN FIELD-SCALE TRANSPORT AND LABORATORY BATCH EXPERIMENTS

EPA Science Inventory

A plausible and consistent model is developed to obtain a quantitative description of the gradual disappearance of hexavalent chromium (Cr(VI)) from groundwater in a small-scale field tracer test and in batch kinetic experiments using aquifer sediments under similar chemical cond...

Effective control of modified palygorskite to NH4+-N release from sediment.

PubMed

Chen, Lei; Zheng, Tianyuan; Zhang, Junjie; Liu, Jie; Zheng, Xilai

2014-01-01

Sediment capping is an in situ treatment technology that can effectively restrain nutrient and pollutant release from the sediment in lakes and reservoirs. Research on sediment capping has focused on the search for effective, non-polluting and affordable capping materials. The efficiency and mechanism of sediment capping with modified palygorskite in preventing sediment ammonia nitrogen (NH4+-N) release to surface water were investigated through a series of batch and sediment capping experiments. Purified palygorskite and different types of modified palygorskite (i.e. heated, acid-modified and NaCI-modified palygorskite) were used in this investigation. Factors affecting control efficiency, including the temperature, thickness and grain size of the capping layer, were also analysed. The batch tests showed that the adsorption of NH4+-N on modified palygorskite achieved an equilibration in the initial 45 min, and the adsorption isotherm followed the Freundlich equation. Sediment capping experiments showed that compared with non-capped condition, covering the sediment with modified palygorskite and sand both inhibited NH4+-N release to the overlying water. Given its excellent chemical stability and strong adsorption, heated palygorskite, which has a NH4+-N release inhibition ratio of 41.3%, is a more effective sediment capping material compared with sand. The controlling effectiveness of the modified palygorskite increases with thicker capping layer, lower temperature and smaller grain size of the capping material.

Salinity Responses of Benthic Microbial Communities in a Solar Saltern (Eilat, Israel)

PubMed Central

Sørensen, Ketil Bernt; Canfield, Donald E.; Oren, Aharon

2004-01-01

The salinity responses of cyanobacteria, anoxygenic phototrophs, sulfate reducers, and methanogens from the laminated endoevaporitic community in the solar salterns of Eilat, Israel, were studied in situ with oxygen microelectrodes and in the laboratory in slurries. The optimum salinity for the sulfate reduction rate in sediment slurries was between 100 and 120‰, and sulfate reduction was strongly inhibited at an in situ salinity of 215‰. Nevertheless, sulfate reduction was an important respiratory process in the crust, and reoxidation of formed sulfide accounted for a major part of the oxygen budget. Methanogens were well adapted to the in situ salinity but contributed little to the anaerobic mineralization in the crust. In slurries with a salinity of 180‰ or less, methanogens were inhibited by increased activity of sulfate-reducing bacteria. Unicellular and filamentous cyanobacteria metabolized at near-optimum rates at the in situ salinity, whereas the optimum salinity for anoxygenic phototrophs was between 100 and 120‰. PMID:15006785

The toxicity of selected gasoline components to glucose methanogenesis by aquifer microorganisms

USGS Publications Warehouse

Mormile, Melanie R.; Suflita, Joseph M.

1996-01-01

Six model hydrocarbons, representing various classes of chemicals found in gasoline, and methyl ethyl ketone, were assayed for their inhibitory effect on glucose methanogenesis in slurries prepared from aquifer sediments and ground water. Biogas (CH4and CO2) production was monitored with an automated pressure transducer system. Benzene, 1-methyl naphthalene, and methyltert-butyl ether (MTBE) were found to have no inhibitory influence on biogas production rates at concentrations up to 71·7 mg/L. Similarly, octane, cyclohexane, indan, and methyl ethyl ketone (MEK) were found to have only marginal negative effects on the rate of biogas production in aquifer slurries, at concentrations ranging from 51·7 to 72·1 mg/L. Thus, gasoline components had low apparent toxicities to microorganisms responsible for glucose methanogenesis in aquifier slurries. As the concentrations of the assayed hydrocarbons are about 100 times those typically reported after an aquifer has been contaminated with gasoline, it is unlikely that individual hydrocarbons will substantially impact anaerobic metabolic processes.

Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudisill, T.S.

1999-08-11

Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitationmore » process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the beta dec ay of plutonium-241) in the dissolved precipitate, a value consistent with the recovery of europium, the americium surrogate.In a subsequent experiment, the plutonium solubility following an oxalate precipitation to simulate the preparation of a slurry feed for a batch melter was 21 mg/mL at 35 degrees C. The increase in solubility compared to the value measured during the pretreatment experiment was attributed to the increased nitrate concentration and ensuing increase in plutonium complexation. The solubility of the plutonium following a precipitant wash with 0.1M oxalic acid was unchanged. The recovery of plutonium from the precipitate slurry was greater than 97 percent allowing an estimation that approximately 92 percent of the plutonium in Tank 17.1 will report to the glass. The behavior of the lanthanides and soluble metal impurities was consistent with the behavior seen during the pretreatment experiment. A trace level material balance showed that 99.9 percent of the americium w as recovered from the precipitate slurry. The overall recovery of americium from the pretreatment and feed preparation processes was greater than 97 percent, which was consistent with the measured recovery of the europium surrogate.« less

30 CFR 77.216-5 - Water, sediment or slurry impoundments and impounding structures; abandonment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... are met: (1) A registered professional engineer, knowledgeable in the principles of dam design and in the design and construction of the structure, shall certify that it substantially conforms to the approved design plan and specifications and that there are no apparent defects. (2) The current owner or...

30 CFR 77.216-5 - Water, sediment or slurry impoundments and impounding structures; abandonment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... are met: (1) A registered professional engineer, knowledgeable in the principles of dam design and in the design and construction of the structure, shall certify that it substantially conforms to the approved design plan and specifications and that there are no apparent defects. (2) The current owner or...

Role of DDL processes during electrolytic reduction of Cu(II) in a low oxygen environment.

PubMed

Brosky, Rebekah T; Pamukcu, Sibel

2013-11-15

Heavy metals typically accumulate in reduced bottom sediments after being discharged into waterways by industrial and municipal processes. A laboratory experiment was conducted in order to determine if abundance of clay in the bottom sediments of a Cu-contaminated aqueous ecosystem could enhance electrolytic reduction of the heavy metal. Cu(NO3)2 · 2.5H2O was added to simulate a moderately contaminated system with 650 μg Cu/ml kaolinite clay-water slurry. A constant electrical potential of 1.0 V/cm was applied across platinum wire electrodes inserted into the continuously stirred system for four days while the system ORP(2) was monitored and periodic sub-samples were taken for analysis. The electrical as well as the chemical results indicate that the quantity of Cu(II) being reduced to Cu(I), especially within the aqueous phase, is increased within the first 48 h of experimentation by the presence of kaolinite clay up to 0.05 mg clay/l slurry. Copyright © 2013 Elsevier B.V. All rights reserved.

A laboratory treatability study on RDX-contaminated soil from the Iowa Army Ammunition Plant, Burlington, Iowa.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boopathy, R.; Manning, J. F.; Environmental Research

2000-03-01

Soil in certain areas of the Iowa Army Ammunition Plant in Burlington, Iowa, was contaminated with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). A laboratory treatability study was conducted to examine the ability of native soil bacteria present in the contaminated site to degrade RDX. The results indicated that RDX can be removed effectively from the soil by native soil bacteria through a co-metabolic process. Molasses, identified as an effective cosubstrate, is inexpensive, and this factor makes the treatment system cost effective. The successful operation of aerobic-anoxic soil-slurry reactors in batch mode with RDX-contaminated soil showed that the technology can be scaled up for fieldmore » demonstration. The RDX concentration in the contaminated soil was decreased by 98% after 4 months of reactor operation. The advantage of the slurry reactor is the simplicity of its operation. The method needs only mixing and the addition of molasses as cosubstrate.« less

DWPF Melter Off-Gas Flammability Assessment for Sludge Batch 9

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, A. S.

2016-07-11

The slurry feed to the Defense Waste Processing Facility (DWPF) melter contains several organic carbon species that decompose in the cold cap and produce flammable gases that could accumulate in the off-gas system and create potential flammability hazard. To mitigate such a hazard, DWPF has implemented a strategy to impose the Technical Safety Requirement (TSR) limits on all key operating variables affecting off-gas flammability and operate the melter within those limits using both hardwired/software interlocks and administrative controls. The operating variables that are currently being controlled include; (1) total organic carbon (TOC), (2) air purges for combustion and dilution, (3)more » melter vapor space temperature, and (4) feed rate. The safety basis limits for these operating variables are determined using two computer models, 4-stage cold cap and Melter Off-Gas (MOG) dynamics models, under the baseline upset scenario - a surge in off-gas flow due to the inherent cold cap instabilities in the slurry-fed melter.« less

Aerobic degradation of petroleum refinery wastewater in sequential batch reactor.

PubMed

Thakur, Chandrakant; Srivastava, Vimal C; Mall, Indra D

2014-01-01

The aim of the present work was to study the effect of various parameters affecting the treatment of raw petroleum refinery wastewater (PRW) having chemical oxygen demand (COD) of 350 mg L(-1) and total organic carbon (TOC) of 70 mg L(-1) in sequential batch reactor (SBR). Effect of hydraulic retention time (HRT) was studied in instantaneous fill condition. Maximum COD and TOC removal efficiencies were found to be 80% and 84%, respectively, for fill phase of 2 h and react phase of 2 h with fraction of SBR being filled with raw PRW in each cycle being 0.4. Effect of parameters was studied in terms of settling characteristic of treated slurry. Kinetics of treatment process has been studied. FTIR and UV-visible analysis of PRW before and after treatment have been performed so as to understand the degradation mechanism.

Competition by aquifer materials in a bimetallic nanoparticle/persulfate system for the treatment of trichloroethylene.

PubMed

Al-Shamsi, Mohammed Ahmad; Thomson, Neil R

2013-10-01

It has been suggested in the literature that aquifer materials can compete with the target organic compounds in an activated peroxygen system. In this study, we employed a rapid treatment method using persulfate activated with bimetallic nanoparticles to investigate the competition between aquifer materials and the dissolved phase of a target organic compound. The concentration of dissolved trichloroethylene (TCE) remaining after using the activated persulfate system was two- to three-fold higher in a soil slurry batch system than in an aqueous batch system. For all five aquifer materials investigated, an increase in the mass of the aquifer solids significantly decreased the degradation of TCE. A linear relationship was observed between the mass of aquifer materials and the initial TCE degradation rate, suggesting that the organic carbon and/or aquifer material constituents (e.g., carbonates and bicarbonates) compete with the oxidation of TCE.

Antifoam Degradation Products in Off Gas and Condensate of Sludge Batch 9 Simulant Nitric-Formic Flowsheet Testing for the Defense Waste Processing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, T.

Ten chemical processing cell (CPC) experiments were performed using simulant to evaluate Sludge Batch 9 for sludge-only and coupled processing using the nitric-formic flowsheet in the Defense Waste Processing Facility (DWPF). Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on eight of the ten. The other two were SRAT cycles only. Samples of the condensate, sludge, and off gas were taken to monitor the chemistry of the CPC experiments. The Savannah River National Laboratory (SRNL) has previously shown antifoam decomposes to form flammable organic products, (hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and propanal), that are presentmore » in the vapor phase and condensate of the CPC vessels. To minimize antifoam degradation product formation, a new antifoam addition strategy was implemented at SRNL and DWPF to add antifoam undiluted.« less

The origin of high sulfate concentrations in a coastal plain aquifer, Long Island, New York

USGS Publications Warehouse

Brown, C.J.; Schoonen, M.A.A.

2004-01-01

Ion-exchange batch experiments were run on Cretaceous (Magothy aquifer) clay cores from a nearshore borehole and an inland borehole on Long Island, NY, to determine the origin of high SO42- concentrations in ground water. Desorption batch tests indicate that the amounts of SO 42- released from the core samples are much greater (980-4700 ??g/g of sediment) than the concentrations in ground-water samples. The locally high SO42- concentrations in pore water extracted from cores are consistent with the overall increase in SO 42- concentrations in ground water along Magothy flow paths. Results of the sorption batch tests indicate that SO42- sorption onto clay is small but significant (40-120 ??g/g of sediment) in the low-pH (<5) pore water of clays, and a significant part of the SO42- in Magothy pore water may result from the oxidation of FeS2 by dissolved Fe(III). The acidic conditions that result from FeS2 oxidation in acidic pore water should result in greater sorption of SO42- and other anions onto protonated surfaces than in neutral-pH pore water. Comparison of the amounts of Cl- released from a clay core sample in desorption batch tests (4 ??g/g of sediment) with the amounts of Cl- sorbed to the same clay in sorption tests (3.7-5 ??g/g) indicates that the high concentrations of Cl- in pore water did not originate from connate seawater but were desorbed from sediment that was previously in contact with seawater. Furthermore, a hypothetical seawater transgression in the past is consistent with the observed pattern of sorbed cation complexes in the Magothy cores and could be a significant source of high SO42- concentrations in Magothy ground water.

Fluidized bed coal desulfurization

NASA Technical Reports Server (NTRS)

Ravindram, M.

1983-01-01

Laboratory scale experiments were conducted on two high volatile bituminous coals in a bench scale batch fluidized bed reactor. Chemical pretreatment and posttreatment of coals were tried as a means of enhancing desulfurization. Sequential chlorination and dechlorination cum hydrodesulfurization under modest conditions relative to the water slurry process were found to result in substantial sulfur reductions of about 80%. Sulfur forms as well as proximate and ultimate analyses of the processed coals are included. These studies indicate that a fluidized bed reactor process has considerable potential for being developed into a simple and economic process for coal desulfurization.

Dehalogenation activities and distribution of reductive dehalogenase homologous genes in marine subsurface sediments.

PubMed

Futagami, Taiki; Morono, Yuki; Terada, Takeshi; Kaksonen, Anna H; Inagaki, Fumio

2009-11-01

Halogenated organic compounds serve as terminal electron acceptors for anaerobic respiration in a diverse range of microorganisms. Here, we report on the widespread distribution and diversity of reductive dehalogenase homologous (rdhA) genes in marine subsurface sediments. A total of 32 putative rdhA phylotypes were detected in sediments from the southeast Pacific off Peru, the eastern equatorial Pacific, the Juan de Fuca Ridge flank off Oregon, and the northwest Pacific off Japan, collected at a maximum depth of 358 m below the seafloor. In addition, significant dehalogenation activity involving 2,4,6-tribromophenol and trichloroethene was observed in sediment slurry from the Nankai Trough Forearc Basin. These results suggest that dehalorespiration is an important energy-yielding pathway in the subseafloor microbial ecosystem.

The treatment of some low-rank coals with carbon dioxide water: Effects on slurry-relevant properties: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slegeir, W.; Sanchez, J.; Coughlan, R.

1986-09-01

This project is concerned with the results of employing CO/sub 2//H/sub 2/O treatments on two low-rank coals. The coals employed in this project were North Dakota lignite from the Indianhead Mine and Utah subbituminous from the Sufco mine. This project is concerned with changes in slurry-relevant characteristics for these low-rank coals due to such treatments. These characteristics include equilibrium moisture, ash content and composition, grindability and slurry rheology. Batch CO/sub 2//water treatments on North Dakota Indianhead lignite afforded a reduction in coal-bound moisture, affording as much as a 35% decrease in equilibrium moisture content. The resulting treated lignite also provedmore » to be a ''cleaner'' coal, with a 30 to 35% reduction in ash content. For the Utah Sufco coal, no appreciable changes in equilibrium moisture were attained and the ash contents generally only slightly reduced Sufco. However, for the more severe treatment, alkaline and alkaline earth were lowered appreciably, with a commensurate increase in ash fusion temperature. For both coals, some improvements in grindability were realized under the most severe treatment conditions (80/sup 0/C, 1200 psi). The less severe conditions afforded little changes in grindability. Some measurements taken of the rheology of treated -200 mesh Indianhead coal slurries have shown non-Newtonian behavior. These slurries settled rapidly when concentrations greater than 50% were reached, hence viscosity measurements were difficult to obtain. Although the mechanism of CO/sub 2//H/sub 2/O action on coal is not clear, the results of this project are consistent with an ion-exchange process, whereby the basic components are exchanged with the hydronium ion of the CO/sub 2//H/sub 2/O mixture. Such ion exchange may lead to other changes in the coal matrix. 38 refs., 8 figs, 18 tabs.« less

Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dan Golomb; Eugene Barry; David Ryan

2005-11-01

This semi-annual progress reports includes further findings on CO{sub 2}-in-Water (C/W) emulsions stabilized by fine particles. In previous semi-annual reports we described the formation of stable C/W emulsions using pulverized limestone (CaCO{sub 3}), flyash, beach sand, shale and lizardite, a rock rich in magnesium silicate. For the creation of these emulsions we used a High-Pressure Batch Reactor (HPBR) equipped with view windows for illumination and video camera recording. For deep ocean sequestration, a C/W emulsion using pulverized limestone may be the most suitable. (a) Limestone (mainly CaCO{sub 3}) is cheap and plentiful; (b) limestone is innocuous for marine organisms (inmore » fact, it is the natural ingredient of shells and corals); (c) it buffers the carbonic acid that forms when CO{sub 2} dissolves in water. For large-scale sequestration of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion a device is needed that mixes the ingredients, liquid carbon dioxide, seawater, and a slurry of pulverized limestone in seawater continuously, rather than incrementally as in a batch reactor. A practical mixing device is a Kenics-type static mixer. The static mixer has no moving parts, and the shear force for mixing is provided by the hydrostatic pressure of liquid CO{sub 2} and CaCO{sub 3} slurry in the delivery pipes from the shore to the disposal depth. This semi-annual progress report is dedicated to the description of the static mixer and the results that have been obtained using a bench-scale static mixer for the continuous formation of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion. The static mixer has an ID of 0.63 cm, length 23.5 cm, number of baffles 27. Under pressure, a slurry of CaCO{sub 3} in artificial seawater (3.5% by weight NaCl) and liquid CO{sub 2} are co-injected into the mixer. From the mixer, the resulting emulsion flows into a Jerguson cell with two oblong windows on opposite sides, then it is vented. A fully ported ball valve inserted after the Jerguson cell allows the emulsion to be stopped in the cell. In such a manner the emulsion can be photographed while it is flowing through the cell, or after it has stagnated in the cell. A slurry of 10 g/L CaCO{sub 3} (Sigma Chemicals C-4830 reagent grade) in artificial seawater, co-injected into the static mixer at a rate of 1.5 L/min with liquid CO{sub 2} at a rate of 150 mL/min, at temperature 5-10 C, pressure 10 MPa, produced an emulsion with mean globule diameter in the 70-100 {micro}m range. In a HPBR, using the same materials, proportions, temperature and pressure, mixed with a magnetic stir bar at 1300 rpm, the mean globule diameter is in the 200-300 {micro}m range. Evidently, the static mixer produces an emulsion with smaller globule diameters and narrower distribution of globule diameters than a batch reactor.« less

Parameterization of erodibility in the Rangeland Hydrology and Erosion Model

USDA-ARS?s Scientific Manuscript database

The magnitude of erosion from a hillslope is governed by the availability of sediment and connectivity of runoff and erosion processes. For undisturbed rangelands, sediment is primarily detached and transported by rainsplash and sheetflow (splash-sheet) processes in isolated bare batches, but sedime...

Fate of 90Sr and U(VI) in Dounreay sediments following saline inundation and erosion.

PubMed

Eagling, Jane; Worsfold, Paul J; Blake, William H; Keith-Roach, Miranda J

2013-08-01

There is concern that sea level rise associated with projected climate change will lead to the inundation, flooding and erosion of soils and sediments contaminated with radionuclides at coastal nuclear sites, such as Dounreay (UK), with seawater. Here batch and column experiments were designed to simulate these scenarios and sequential extractions were used to identify the key radionuclide solid phase associations. Strontium was exchangeable and was mobilised rapidly by ion exchange with seawater Mg(2+) in both batch and column experiments. In contrast, U was more strongly bound to the sediments and mobilisation was initially limited by the influence of the sediment on the pH of the water. Release was only observed when the pH increased above 6.9, suggesting that the formation of soluble U(VI)-carbonate species was important. Under dynamic flow conditions, long term release was significant (47%), but controlled by slow desorption kinetics from a range of binding sites. Copyright © 2013 Elsevier Ltd. All rights reserved.

Combined substrate, enzyme and yeast feed in simultaneous saccharification and fermentation allow bioethanol production from pretreated spruce biomass at high solids loadings

PubMed Central

2014-01-01

Background Economically feasible cellulosic ethanol production requires that the process can be operated at high solid loadings, which currently imparts technical challenges including inefficient mixing leading to heat and mass transfer limitations and high concentrations of inhibitory compounds hindering microbial activity during simultaneous saccharification and fermentation (SSF) process. Consequently, there is a need to develop cost effective processes overcoming the challenges when working at high solid loadings. Results In this study we have modified the yeast cultivation procedure and designed a SSF process to address some of the challenges at high water insoluble solids (WIS) content. The slurry of non-detoxified pretreated spruce when used in a batch SSF at 19% (w/w) WIS was found to be inhibitory to Saccharomyces cerevisiae Thermosacc that produced 2 g l-1 of ethanol. In order to reduce the inhibitory effect, the non-washed solid fraction containing reduced amount of inhibitors compared to the slurry was used in the SSF. Further, the cells were cultivated in the liquid fraction of pretreated spruce in a continuous culture wherein the outflow of cell suspension was used as cell feed to the SSF reactor in order to maintain the metabolic state of the cell. Enhanced cell viability was observed with cell, enzyme and substrate feed in a SSF producing 40 g l-1 ethanol after 96 h corresponding to 53% of theoretical yield based on available hexose sugars compared to 28 g l-1 ethanol in SSF with enzyme and substrate feed but no cell feed resulting in 37% of theoretical yield at a high solids loading of 20% (w/w) WIS content. The fed-batch SSF also significantly eased the mixing, which is usually challenging in batch SSF at high solids loading. Conclusions A simple modification of the cell cultivation procedure together with a combination of yeast, enzyme and substrate feed in a fed-batch SSF process, made it possible to operate at high solids loadings in a conventional bioreactor. The proposed process strategy significantly increased the yeast cell viability and overall ethanol yield. It was also possible to obtain 4% (w/v) ethanol concentration, which is a minimum requirement for an economical distillation process. PMID:24713027

Combined substrate, enzyme and yeast feed in simultaneous saccharification and fermentation allow bioethanol production from pretreated spruce biomass at high solids loadings.

PubMed

Koppram, Rakesh; Olsson, Lisbeth

2014-04-08

Economically feasible cellulosic ethanol production requires that the process can be operated at high solid loadings, which currently imparts technical challenges including inefficient mixing leading to heat and mass transfer limitations and high concentrations of inhibitory compounds hindering microbial activity during simultaneous saccharification and fermentation (SSF) process. Consequently, there is a need to develop cost effective processes overcoming the challenges when working at high solid loadings. In this study we have modified the yeast cultivation procedure and designed a SSF process to address some of the challenges at high water insoluble solids (WIS) content. The slurry of non-detoxified pretreated spruce when used in a batch SSF at 19% (w/w) WIS was found to be inhibitory to Saccharomyces cerevisiae Thermosacc that produced 2 g l-1 of ethanol. In order to reduce the inhibitory effect, the non-washed solid fraction containing reduced amount of inhibitors compared to the slurry was used in the SSF. Further, the cells were cultivated in the liquid fraction of pretreated spruce in a continuous culture wherein the outflow of cell suspension was used as cell feed to the SSF reactor in order to maintain the metabolic state of the cell. Enhanced cell viability was observed with cell, enzyme and substrate feed in a SSF producing 40 g l-1 ethanol after 96 h corresponding to 53% of theoretical yield based on available hexose sugars compared to 28 g l-1 ethanol in SSF with enzyme and substrate feed but no cell feed resulting in 37% of theoretical yield at a high solids loading of 20% (w/w) WIS content. The fed-batch SSF also significantly eased the mixing, which is usually challenging in batch SSF at high solids loading. A simple modification of the cell cultivation procedure together with a combination of yeast, enzyme and substrate feed in a fed-batch SSF process, made it possible to operate at high solids loadings in a conventional bioreactor. The proposed process strategy significantly increased the yeast cell viability and overall ethanol yield. It was also possible to obtain 4% (w/v) ethanol concentration, which is a minimum requirement for an economical distillation process.

The effectiveness of aerial hydromulch as an erosion control treatment in burned chaparral watersheds

Treesearch

Pete Wohlgemuth; Jan Beyers; Pete Robichaud

2011-01-01

High severity wildfire can make watersheds susceptible to accelerated erosion, which impedes resource recovery and threatens life, property, and infrastructure in downstream human communities. Land managers often use mitigation measures on the burned hillside slopes to reduce postfire sediment fluxes. Hydromulch, a slurry of paper or wood fiber that dries to a...

30 CFR 77.216-2 - Water, sediment, or slurry impoundments and impounding structures; minimum plan requirements...

Code of Federal Regulations, 2010 CFR

2010-07-01

... instrumentation. (9) Graphs showing area-capacity curves. (10) A statement of the runoff attributable to the probable maximum precipitation of 6-hour duration and the calculations used in determining such runoff. (11) A statement of the runoff attributable to the storm for which the structure is designed and the...

What food and feeding rates are optimum for the Chironomus dilutus sediment toxicity test method?

EPA Science Inventory

Laboratory tests with benthic macroinvertebrates conducted using standard toxicity test procedures are used to assess the potential toxicity of contaminated sediments. Results are compared across sites or for batches of samples, and the performance of organisms in control treatme...

DWPF DECON FRIT: SUMP AND SLURRY SOLIDS ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C.; Peeler, D.; Click, D.

The Savannah River National Laboratory (SRNL) has been requested to perform analyses on samples of the Defense Waste Processing Facility (DWPF) decon frit slurry (i.e., supernate samples and sump solid samples). Four 1-L liquid slurry samples were provided to SRNL by Savannah River Remediation (SRR) from the 'front-end' decon activities. Additionally, two 1-L sump solids samples were provided to SRNL for compositional and physical analysis. In this report, the physical and chemical characterization results of the slurry solids and sump solids are reported. Crawford et al. (2010) provide the results of the supernate analysis. The results of the sump solidsmore » are reported on a mass basis given the samples were essentially dry upon receipt. The results of the slurry solids were converted to a volume basis given approximately 2.4 grams of slurry solids were obtained from the {approx}4 liters of liquid slurry sample. Although there were slight differences in the analytical results between the sump solids and slurry solids the following general summary statements can be made. Slight differences in the results are also captured for specific analysis. (1) Physical characterization - (a) SEM/EDS analysis suggested that the samples were enriched in Li and Si (B and Na not detectable using the current EDS system) which is consistent with two of the four principle oxides of Frit 418 (B{sub 2}O{sub 3}, Na{sub 2}O, Li{sub 2}O and SiO{sub 2}). (b) SEM/EDS analysis also identified impurities which were elementally consistent with stainless steel (i.e., Fe, Ni, Cr contamination). (c) XRD results indicated that the sump solids samples were amorphous which is consistent with XRD results expected for a Frit 418 based sample. (d) For the sump solids, SEM/EDS analysis indicated that the particle size of the sump solids were consistent with that of an as received Frit 418 sample from a current DWPF vendor. (e) For the slurry solids, SEM/EDS analysis indicated that the particle size range of the slurry solids was much broader than compared to the sump solids. More specifically, there were significantly more fines in the slurry solids as compared to the sump solids. (f) PSD results indicated that > 99% of both the sump and slurry solids were less than 350 microns. The PSD results also supported SEM/EDS analysis that there were significantly more fines in the slurry solids as compared to the sump solids. (2) Weight Percent Solids - Based on the measured supernate density and mass of insoluble solids (2.388 grams) filtered from the four liters of liquid slurry samples, the weight percent insoluble solids was estimated to be 0.060 wt%. This level of insoluble solids is higher than the ETP WAC limit of 100 mg/L, or 0.01 wt% which suggests a separation technology of some type would be required. (3) Chemical Analysis - (a) Elemental results from ICP-ES analysis indicated that the sump solids and slurry were very consistent with the nominal composition of Frit 418. There were other elements identified by ICP analysis which were either consistent with the presence of stainless steel (as identified by SEM/EDS analysis) or impurities that have been observed in 'as received' Frit 418 from the vendor. (b) IC anion analysis of the sump solids and slurry solids indicated all of the species were less than detection limits. (c) Radionuclide analysis of the sump solids also indicated that most of the analytes were either at or below the detection limits. (d) Organic analysis of the sump solids and slurry solids indicated all of the species were less than detection limits. It should be noted that the results of this study may not be representative of future decon frit solutions or sump/slurry solids samples. Therefore, future DWPF decisions regarding the possible disposal pathways for either the aqueous or solid portions of the Decon Frit system need to factor in the potential differences. More specifically, introduction of a different frit or changes to other DWPF flowsheet unit operations (e.g., different sludge batch or coupling with other process streams) may impact not only the results but also the conclusions regarding acceptability with respect to the ETF WAC limits or other alternative disposal options.« less

Thin-film versus slurry-phase carbonation of steel slag: CO₂ uptake and effects on mineralogy.

PubMed

Baciocchi, R; Costa, G; Di Gianfilippo, M; Polettini, A; Pomi, R; Stramazzo, A

2015-01-01

The results of direct aqueous accelerated carbonation of three types of steel manufacturing residues, including an electric arc furnace (EAF) slag and two basic oxygen furnace (BOF) slags, are reported. Batch accelerated carbonation tests were conducted at different temperatures and CO2 pressures applying the thin-film route (liquid to solid, L/S, ratio=0.3L/kg) or the slurry-phase route (L/S ratio=5L/kg). The CO2 uptake strongly depended on both the slag characteristics and the process route; maximum yields of 280 (EAF), 325 (BOF1) and 403 (BOF2) gCO2/kg slag were achieved in slurry phase at T=100°C and pCO2=10 bar. Differently from previous studies, additional carbonates (other than Ca-based phases) were retrieved in the carbonated BOF slags, indicating that also Mg-, Fe- and Mn-containing phases partially reacted with CO2 under the tested conditions. The results hence show that the effects of accelerated carbonation in terms of CO2 uptake capacity, yield of mineral conversion into carbonates and mineralogy of the treated product, strongly rely on several factors. These include, above all, the mineralogy of the original material and the operating conditions adopted, which thus need specific case-by-case optimization to maximize the CO2 sequestration yield. Copyright © 2014 Elsevier B.V. All rights reserved.

Degradation of nitrobenzene-containing wastewater by carbon nanotubes immobilized nanoscale zerovalent iron

NASA Astrophysics Data System (ADS)

Jiao, Weizhou; Feng, Zhirong; Liu, Youzhi; Jiang, Huihui

2016-07-01

Nanoscaled zerovalent iron (NZVI)-multiwalled carbon nanotubes (CNTs) composite materials were prepared by in situ reduction of Fe2+ onto CNTs for nitrobenzene (NB) degradation. The morphologies and the composites of the prepared materials were characterized by SEM, TEM, and XRD. The results showed that the agglomeration of NZVI decreased with NZVI dispersed well onto the surfaces of CNTs, the particle size of NZVI on CNTs was about 20-50 nm. The BET surface areas of NZVI-CNTs was about 95.8 m2/g, which was 39 % higher than that of bare NZVI. For storage, the prepared NZVI-CNTs were concentrated into slurry and stored in situ as fresh slurry without drying. Contrast experiment results showed that the removal efficiency of NB by NZVI-CNTs fresh slurry was 30 % higher than that of vacuum-dried NZVI-CNTs, which indicates that storing in situ as fresh slurry can be an alternative strategy for nanoparticle storage. Batch experiment results showed that NB could be degraded to aniline by NZVI-CNTs rapidly, and the appropriate pH can be conducted at a relatively wide range from 2.0 to 9.0. The optimum mass ratio of iron-carbon was 1:1, and removal efficiency of NB by NZVI-CNTs with this mass ratio can achieve 100 % within 1 min. The degradation process of NB to intermediates was accelerated significantly by NZVI-CNTs, however, there was still a long term for the intermediates to transfer completely into the final product of aniline. The existence of CNTs can improve the formation of aniline through accelerating the electron transfer by forming microscopic galvanic cells with NZVI.

Integration of the Uncertainties of Anion and TOC Measurements into the Flammability Control Strategy for Sludge Batch 8 at the DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T. B.

2013-03-14

The Savannah River National Laboratory (SRNL) has been working with the Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) in the development and implementation of a flammability control strategy for DWPF’s melter operation during the processing of Sludge Batch 8 (SB8). SRNL’s support has been in response to technical task requests that have been made by SRR’s Waste Solidification Engineering (WSE) organization. The flammability control strategy relies on measurements that are performed on Slurry Mix Evaporator (SME) samples by the DWPF Laboratory. Measurements of nitrate, oxalate, formate, and total organic carbon (TOC) standards generated by the DWPF Laboratory aremore » presented in this report, and an evaluation of the uncertainties of these measurements is provided. The impact of the uncertainties of these measurements on DWPF’s strategy for controlling melter flammability also is evaluated. The strategy includes monitoring each SME batch for its nitrate content and its TOC content relative to the nitrate content and relative to the antifoam additions made during the preparation of the SME batch. A linearized approach for monitoring the relationship between TOC and nitrate is developed, equations are provided that integrate the measurement uncertainties into the flammability control strategy, and sample calculations for these equations are shown to illustrate the impact of the uncertainties on the flammability control strategy.« less

Upscaling of U (VI) desorption and transport from decimeter‐scale heterogeneity to plume‐scale modeling

USGS Publications Warehouse

Curtis, Gary P.; Kohler, Matthias; Kannappan, Ramakrishnan; Briggs, Martin A.; Day-Lewis, Frederick D.

2015-01-01

Scientifically defensible predictions of field scale U(VI) transport in groundwater requires an understanding of key processes at multiple scales. These scales range from smaller than the sediment grain scale (less than 10 μm) to as large as the field scale which can extend over several kilometers. The key processes that need to be considered include both geochemical reactions in solution and at sediment surfaces as well as physical transport processes including advection, dispersion, and pore-scale diffusion. The research summarized in this report includes both experimental and modeling results in batch, column and tracer tests. The objectives of this research were to: (1) quantify the rates of U(VI) desorption from sediments acquired from a uranium contaminated aquifer in batch experiments;(2) quantify rates of U(VI) desorption in column experiments with variable chemical conditions, and(3) quantify nonreactive tracer and U(VI) transport in field tests.

Anthropogenic and geogenic Cd, Hg, Pb and Se sources of contamination in a brackish aquifer below agricultural fields

NASA Astrophysics Data System (ADS)

Mastrocicco, Micòl; Colombani, Nicolò; Di Giuseppe, Dario; Faccini, Barbara; Ferretti, Giacomo; Coltorti, Massimo

2015-04-01

Groundwater quality is often threatened by industrial, agricultural and land use practices (anthropogenic input). In deltaic areas is however difficult to distinguish between geogenic and anthropogenic inorganic contaminants pollution, since these phenomena can influence each other and often display a seasonal cycling. The effect of geogenic groundwater ionic strength (>10 g/l) on the mobility of trace elements like Cd, Hg, Pb and Se was studied in combination with the anthropogenic sources of these elements (fertilizers) in a shallow aquifer. The site is located in the Po river plain (Northern Italy) in an agricultural field belonging to a reclaimed deltaic environment, near Codigoro town. It is 6 ha wide and is drained by a subsurface drainage system made of PVC tile drains with a slope of 3‰, which provides gravity drainage towards two ditches that in turn discharge in a main channel. The whole area has been intensively cultivated with cereal rotation since 1960, mainly using synthetic urea as nitrogen fertilizer at an average rate of 180 kg-N/ha/y and pig slurry at an average rate of 60 kg-N/ha/y. The sediments were analyzed for major and trace elements via XRF, while major ions in groundwater were analyzed via IC and trace elements via ICP-MS. Three monitoring wells, with an inner diameter of 2 cm and screened down to 4 m below ground level, were set up in the field and sampled every four month from 2012 to 2014. The use of intensive depth profiles with resolution of 0.5 m in three different locations, gave insights into groundwater and sediment matrix interactions. To characterize the anthropogenic inputs synthetic urea and pig slurry were analyzed for trace elements via ICP-MS. The synthetic urea is a weak source of Cd and Hg (~1 ppb), while Se and Pb are found below detection limits. The pig slurry is a much stronger source of Se (~19 ppb) and Pb (~23 ppb) and a weak source of Cd (~3 ppb) and Hg (~2 ppb). Although, the mass loading rate pig slurry is three times lower than the synthetic urea on yearly basis. In general Cd, Hg, Pb and Se concentrations were found lower in sandy sediments, since usually these elements concentrate in the clay fraction. Hg, Pb and Se groundwater concentrations generally increased with the ionic strength of the solution witnessing a geogenic origin, while Cd groundwater concentrations were not clearly related to saline groundwater. Most probably, the latter was released both by fertilizers and by sediments during shifts between oxic and reducing conditions. In addition, the elevated soil organic carbon induced reducing conditions throughout the saturated aquifer profile (usually below the tile drains), which further promoted Hg, Pb and Se dissolution. The combined use of high-resolution sediment profiles, seasonal groundwater sampling and end-member analyses seems to be a promising procedure to distinguish between anthropogenic inorganic contaminants input and geogenic contribution in reclaimed deltaic environments.

Nanometer-sized ceria-coated silica-iron oxide for the reagentless microextraction/preconcentration of heavy metals in environmental and biological samples followed by slurry introduction to ICP-OES.

PubMed

Dados, A; Paparizou, E; Eleftheriou, P; Papastephanou, C; Stalikas, C D

2014-04-01

A slurry suspension sampling technique is developed and optimized for the rapid microextraction of heavy metals and analysis using nanometer-sized ceria-coated silica-iron oxide particles and inductively coupled plasma optical emission spectrometry (ICP-OES). Magnetic-silica material is synthesized by a co-precipitation and sol-gel method followed by ceria coating through a precipitation. The large particles are removed using a sedimentation-fractionation procedure and a magnetic homogeneous colloidal suspension of ceria-modified iron oxide-silica is produced for microextraction. The nanometer-sized particles are separated from the sample solution magnetically and analyzed with ICP-OES using a slurry suspension sampling approach. The ceria-modified iron oxide-silica does not contain any organic matter and this probably justifies the absence of matrix effect on plasma atomization capacity, when increased concentrations of slurries are aspirated. The As, Be, Mo, Cr, Cu, Pb, Hg, Sb, Se and V can be preconcentrated by the proposed method at pH 6.0 while Mn, Cd, Co and Ni require a pH ≥ 8.0. Satisfactory values are obtained for the relative standard deviations (2-6%), recoveries (88-102%), enrichment factors (14-19) and regression correlation coefficients as well as detectability, at sub-μg L(-1) levels. The applicability of magnetic ceria for the microextraction of metal ions in combination with the slurry introduction technique using ICP is substantiated by the analysis of environmental water and urine samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterizing The Microbial Lability And Isotopic (14C, 13C) Signatures Of Marine Organic Matter With A Novel Culture Vessel System

NASA Astrophysics Data System (ADS)

Beaupre, S. R.; Mahmoudi, N.; Pearson, A.

2016-02-01

The rate at which non-living organic matter is respired in the ocean is an unconstrained and important property of the marine carbon cycle. Studies of inherent mineralization rates are complicated by the fact that marine organic matter is a mixture of compounds that vary in reactivity and concentration. While natural radiocarbon ages (14C, half-life = 5730 yr) have served as proxies for lability, they have not been used extensively to characterize that fraction of marine organic matter that is biologically accessible. To address this problem, we developed a novel batch culture system to monitor the time-dependent production rates and isotopic signatures of CO2 released during microbial degradation of natural organic matter. The system simulated a nepheloid layer by maintaining a slurry of decarbonated sediment and minimal media (M9) in a custom 2-liter culture vessel. The natural microbial community was allowed to develop within the sediment, and respired CO2 was continuously sparged from the medium with helium and oxygen, quantified in real time with an infrared gas analyzer, and isolated as a series of contiguous fractions for subsequent isotopic (∆14C, d13C) characterization. Control experiments indicated the accumulation of just 4.5 mg of background carbon per hour of continuous gas flow, which constituted ≤ 10 % of the respired carbon mass in each fraction. Since ∆14C values are conserved during molecular transformations, this low-blank system enables the detection of subtle shifts in the "age" of organic matter respired during the course of a culture experiment. Analyses of sediments from Falmouth, MA revealed both a variable CO2 production rate and an increase in post-bomb ∆14C values during a 10-day incubation. This suggests that the microbial lability of organic matter at this site decreased non-linearly with apparent 14C age, and that the least labile fraction observed was not more than 50 years old. These results underscore the complex relationship between microbial communities, organic matter composition, and its 14C age distribution.

Contaminant concentration versus flow velocity: drivers of biodegradation and microbial growth in groundwater model systems.

PubMed

Grösbacher, Michael; Eckert, Dominik; Cirpka, Olaf A; Griebler, Christian

2018-06-01

Aromatic hydrocarbons belong to the most abundant contaminants in groundwater systems. They can serve as carbon and energy source for a multitude of indigenous microorganisms. Predictions of contaminant biodegradation and microbial growth in contaminated aquifers are often vague because the parameters of microbial activity in the mathematical models used for predictions are typically derived from batch experiments, which don't represent conditions in the field. In order to improve our understanding of key drivers of natural attenuation and the accuracy of predictive models, we conducted comparative experiments in batch and sediment flow-through systems with varying concentrations of contaminant in the inflow and flow velocities applying the aerobic Pseudomonas putida strain F1 and the denitrifying Aromatoleum aromaticum strain EbN1. We followed toluene degradation and bacterial growth by measuring toluene and oxygen concentrations and by direct cell counts. In the sediment columns, the total amount of toluene degraded by P. putida F1 increased with increasing source concentration and flow velocity, while toluene removal efficiency gradually decreased. Results point at mass transfer limitation being an important process controlling toluene biodegradation that cannot be assessed with batch experiments. We also observed a decrease in the maximum specific growth rate with increasing source concentration and flow velocity. At low toluene concentrations, the efficiencies in carbon assimilation within the flow-through systems exceeded those in the batch systems. In all column experiments the number of attached cells plateaued after an initial growth phase indicating a specific "carrying capacity" depending on contaminant concentration and flow velocity. Moreover, in all cases, cells attached to the sediment dominated over those in suspension, and toluene degradation was performed practically by attached cells only. The observed effects of varying contaminant inflow concentration and flow velocity on biodegradation could be captured by a reactive-transport model. By monitoring both attached and suspended cells we could quantify the release of new-grown cells from the sediments to the mobile aqueous phase. Studying flow velocity and contaminant concentrations as key drivers of contaminant transformation in sediment flow-through microcosms improves our system understanding and eventually the prediction of microbial biodegradation at contaminated sites.

Tolerance of freshwater test organisms to formulated sediments for use as control materials in whole-sediment toxicity tests

USGS Publications Warehouse

Kemble, N.E.; Dwyer, F.J.; Ingersoll, C.G.; Dawson, T.D.; Norberg-King, T. J.

1999-01-01

A method is described for preparing formulated sediments for use intoxicity testing. Ingredients used to prepare formulated sediments included commercially available silt, clay, sand, humic acid, dolomite, and α-cellulose (as a source of organic carbon). α-Cellulose was selected as the source of organic carbon because it is commercially available, consistent from batch to batch, and low in contaminant concentrations. The tolerance of freshwater test organisms to formulated sediments for use as control materials in whole-sediment toxicity testing was evaluated. Sediment exposures were conducted for 10 d with the amphipod Hyalella azteca, the midges Chironomus riparius and C. tentans, and the oligochaete Lumbriculus variegatus and for 28 d with H. azteca. Responses of organisms in formulated sediments was compared with a field-collected control sediment that has routinely been used to determine test acceptability. Tolerance of organisms to formulated sediments was evaluated by determining responses to varying levels of α-cellulose, to varying levels of grain size, to evaluation of different food types, or to evaluation of different sources of overlying water. In the 10-d exposures, survival of organisms exposed to the formulated sediments routinely met or exceeded the responses of test organisms exposed to the control sediment and routinely met test acceptability criteria required in standard methods. Growth of amphipods and oligochaetes in 10-d exposures with formulated sediment was often less than growth of organisms in the field-collected control sediment. Additional research is needed, using the method employed to prepare formulated sediment, to determine if conditioning formulated sediments before starting 10-d tests would improve the growth of amphipods. In the 28-d exposures, survival of H. azteca was low when reconstituted water was used as the source of overlying water. However, when well water was used as the source of overlying water in 28-d exposures, consistent responses of amphipods were observed in both formulated and control sediments.

Design of Mixed Batch Reactor and Column Studies at Oak Ridge National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Weimin; Criddle, Craig S.

2015-11-16

We (the Stanford research team) were invited as external collaborators to contribute expertise in environmental engineering and field research at the ORNL IFRC, Oak Ridge, TN, for projects carried out at the Argonne National Laboratory and funded by US DOE. Specifically, we assisted in the design of batch and column reactors using ORNL IFRC materials to ensure the experiments were relevant to field conditions. During the funded research period, we characterized ORNL IFRC groundwater and sediments in batch microcosm and column experiments conducted at ANL, and we communicated with ANL team members through email and conference calls and face-to-face meetingsmore » at the annual ERSP PI meeting and national meetings. Microcosm test results demonstrated that U(VI) in sediments was reduced to U(IV) when amended with ethanol. The reduced products were not uraninite but unknown U(IV) complexes associated with Fe. Fe(III) in solid phase was only partially reduced. Due to budget reductions at ANL, Stanford contributions ended in 2011.« less

Colloidal aspects and packing behaviour of charged microparticulates in high efficiency ion chromatography.

PubMed

Wahab, M Farooq; Pohl, Christopher A; Lucy, Charles A

2012-12-28

The development of small particles in ion chromatography (IC) is a recent phenomenon. Very few studies are available on packing polymeric particles bearing ionizable functional groups. This study explores the colloidal and rheological properties that govern slurry packing to form high efficiency IC columns. The polymeric substrate used was non-porous 4.4 μm sulfonated ethylvinylbenzene–divinylbenzene (1.4 mequiv. SO(3)H/g resin) with 55% crosslink. We developed simple tests optical microscopy and sedimentation tests for predicting the quality of packed columns. The negatively charged particles (zeta potential: −52 mV in water) behave like colloids. The influence of counter-ion charge (Al(3+), Mg(2+), Na(+)) and ionic strength on column efficiency followed the Schulze–Hardy rule. Highly flocculating slurries give poorly packed columns with N ~ 900 whereas under non-agglomerating slurry conditions efficiencies up to N > 10,000 can be achieved. A non-agglomerating slurry also shows non-Newtonian behaviour, specifically shear thickening. Packing at lower flow rate (<1 mL/min) or higher temperature (>50 °C) reduces the shear thickening and produces higher efficiency columns. The packed sulfonated resin column is coated with 72 nm quaternary ammonium bearing latex (AS4A) and used in the separation of F(−), Cl(−), NO(2)(−), Br(−), and NO(3)(−) yielding a reduced plate height of 1.9 under optimum conditions.

Dewatering of contaminated river sediments

NASA Technical Reports Server (NTRS)

Church, Ronald H.; Smith, Carl W.; Scheiner, Bernard J.

1994-01-01

Dewatering of slurries has been successfully accomplished by the proper use of polymers in flocculating the fine particulate matter suspended in mineral processing streams. The U.S. Bureau of Mines (USBM) entered into a cooperative research effort with the U.S. Army Corps of Engineers (Corps) for the purpose of testing and demonstrating the applicability of mining flocculation technology to dredging activities associated with the removal of sediments from navigable waterways. The Corps has the responsibility for maintaining the navigable waterways in the United States. Current technology relies primarily on dredging operations which excavate the material from the bottom of waterways. The Corps is testing new dredging technology which may reduce resuspension of sediments by the dredging operation. Pilot plant dredging equipment was tested by the Corps which generated larger quantities of water when compared to conventional equipment, such as the clam shell. The transportation of this 'excess' water adds to the cost of sediment removal. The process developed by the USBM consists of feed material from the barge being pumped through a 4-in line by a centrifugal pump and exiting through a 4-in PVC delivery system. A 1,000-gal fiberglass tank was used to mix the polymer concentrate. The polymer was pumped through a 1-in line using a variable speed progressive cavity pump and introduced to the 4-in feed line prior to passing through a 6-in by 2-ft static mixer. The polymer/feed slurry travels to the clarifying tank where the flocculated material settled to the bottom and allowed 'clean' water to exit the overflow. A pilot scale flocculation unit was operated on-site at the Corps' 'Confined Disposal Facility' in Buffalo, NY.

Watershed scale fungal community characterization along a pH gradient in a subsurface environment co-contaminated with uranium and nitrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jasrotia, Puja; Green, Stefan; Canion, Andy

2014-01-01

The objective of this study was to characterize fungal communities in a subsurface environment co-contaminated with uranium and nitrate at the watershed scale, and to determine the potential contribution of fungi to contaminant transformation (nitrate attenuation). The abundance, distribution and diversity of fungi in subsurface groundwater samples were determined using quantitative and semi-quantitative molecular techniques, including quantitative PCR of eukaryotic SSU rRNA genes and pyrosequencing of fungal internal transcribed spacer (ITS) regions. Potential bacterial and fungal denitrification was assessed in sediment-groundwater slurries amended with antimicrobial compounds and in fungal pure cultures isolated from subsurface. Our results demonstrate that subsurface fungalmore » communities are dominated by members of the phylum Ascomycota, and a pronounced shift in fungal community composition occurs across the groundwater pH gradient at the field site, with lower diversity observed under acidic (pH < 4.5) conditions. Fungal isolates recovered from subsurface sediments were shown to reduce nitrate to nitrous oxide, including cultures of the genus Coniochaeta that were detected in abundance in pyrosequence libraries of site groundwater samples. Denitrifying fungal isolates recovered from the site were classified, and found to be distributed broadly within the phylum Ascomycota, and within a single genus within the Basidiomycota. Potential denitrification rate assays with sediment-groundwater slurries showed the potential for subsurface fungi to reduce nitrate to nitrous oxide under in situ acidic pH conditions.« less

Watershed-Scale Fungal Community Characterization along a pH Gradient in a Subsurface Environment Cocontaminated with Uranium and Nitrate

PubMed Central

Jasrotia, Puja; Green, Stefan J.; Canion, Andy; Overholt, Will A.; Prakash, Om; Wafula, Denis; Hubbard, Daniela; Watson, David B.; Schadt, Christopher W.; Brooks, Scott C.

2014-01-01

The objective of this study was to characterize fungal communities in a subsurface environment cocontaminated with uranium and nitrate at the watershed scale and to determine the potential contribution of fungi to contaminant transformation (nitrate attenuation). The abundance, distribution, and diversity of fungi in subsurface groundwater samples were determined using quantitative and semiquantitative molecular techniques, including quantitative PCR of eukaryotic small-subunit rRNA genes and pyrosequencing of fungal internal transcribed spacer (ITS) regions. Potential bacterial and fungal denitrification was assessed in sediment-groundwater slurries amended with antimicrobial compounds and in fungal pure cultures isolated from the subsurface. Our results demonstrate that subsurface fungal communities are dominated by members of the phylum Ascomycota, and a pronounced shift in fungal community composition occurs across the groundwater pH gradient at the field site, with lower diversity observed under acidic (pH <4.5) conditions. Fungal isolates recovered from subsurface sediments, including cultures of the genus Coniochaeta, which were detected in abundance in pyrosequence libraries of site groundwater samples, were shown to reduce nitrate to nitrous oxide. Denitrifying fungal isolates recovered from the site were classified and found to be distributed broadly within the phylum Ascomycota and within a single genus of the Basidiomycota. Potential denitrification rate assays with sediment-groundwater slurries showed the potential for subsurface fungi to reduce nitrate to nitrous oxide under in situ acidic pH conditions. PMID:24389927

Heat transfer and hydrodynamic investigations of a baffled slurry bubble column

NASA Astrophysics Data System (ADS)

Saxena, S. C.; Chen, Z. D.

1992-09-01

Heat transfer and hydrodynamic investigations have been conducted in a 0.108 m internal diameter bubble column at ambient conditions. The column is equipped with seven 19mm diameter tubes arranged in an equilateral triangular pitch of 36.5 mm. A Monsanto synthetic heat transfer fluid, Therminol-66 having a viscosity of 39.8 cP at 303 K, is used as a liquid medium. Magnetite powders, average diameters 27.7 and 36.6 µm, in five concentrations up to 50 weight percent in the slurry, are used. As a gas phase, industrial grade nitrogen of purity 99.6 percent is employed. Gas holdup in different operating modes and regimes have been measured for the two- and three-phase systems over a superficial gas velocity range up to 0.20 m/s in the semi-batch mode. Heat transfer coefficients are measured at different tube locations in the bundle at different radial and vertical locations over a range of operating conditions. All these data are compared with the existing literature correlations and models. New correlations are proposed.

Materials Engineering and Scale Up of Fluid Phase Chemical Hydrogen Storage for Automotive Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westman, Matthew P.; Chun, Jaehun; Choi, Young Joon

Among candidates for chemical hydrogen storage in PEM fuel cell automotive applications, ammonia borane (AB, NH3BH3) is considered to be one of the most promising materials due to its high hydrogen content of 14-16 wt% below 200°C and high volumetric density. In our previous paper, we selected AB in silicone oil as a role model for a slurry hydrogen storage system. Materials engineering properties were optimized by increasing solid loading by using an ultra-sonic process. In this paper, we proceeded to scale up to liter size batches with solid loadings up to 50 wt% (8 wt% H2) with dynamic viscositiesmore » less than 1000cP at 25°C. The use of a non-ionic surfactant, Triton X-15, shows significant promise in controlling the level of foaming produced during the thermal dehydrogenation of the AB. Through the development of new and efficient processing techniques and the ability to adequately control the foaming, stable homogenous slurries of high solid loading have been demonstrated as a viable hydrogen delivery source.« less

Remediation of groundwater contaminated with arsenic through enhanced natural attenuation: Batch and column studies.

PubMed

Hafeznezami, Saeedreza; Zimmer-Faust, Amity G; Jun, Dukwoo; Rugh, Megyn B; Haro, Heather L; Park, Austin; Suh, Jae; Najm, Tina; Reynolds, Matthew D; Davis, James A; Parhizkar, Tarannom; Jay, Jennifer A

2017-10-01

Batch and column laboratory experiments were conducted on natural sediment and groundwater samples from a contaminated site in Maine, USA with the aim of lowering the dissolved arsenate [As(V)] concentrations through chemical enhancement of natural attenuation capacity. In batch factorial experiments, two levels of treatment for three parameters (pH, Ca, and Fe) were studied at different levels of phosphate to evaluate their impact on As(V) solubility. Results illustrated that lowering pH, adding Ca, and adding Fe significantly increased the sorption capacity of sediments. Overall, Fe amendment had the highest individual impact on As(V) levels. To provide further evidence for the positive impact of Ca on As(V) adsorption, isotherm experiments were conducted at three different levels of Ca concentrations. A consistent increase in adsorption capacity (26-37%) of sediments was observed with the addition of Ca. The observed favorable effect of Ca on As(V) adsorption is likely caused by an increase in the surface positive charges due to surface accumulation of Ca 2+ ions. Column experiments were conducted by flowing contaminated groundwater with elevated pH, As(V), and phosphate through both uncontaminated and contaminated sediments. Potential in-situ remediation scenarios were simulated by adding a chemical amendment feed to the columns injecting Fe(II) or Ca as well as simultaneous pH adjustment. Results showed a temporary and limited decrease in As(V) concentrations under the Ca treatment (39-41%) and higher levels of attenuation in Fe(II) treated columns (50-91%) but only after a certain number of pore volumes (18-20). This study illustrates the importance of considering geochemical parameters including pH, redox potential, presence of competing ions, and sediment chemical and physical characteristics when considering enhancing the natural attenuation capacity of sediments to mitigate As contamination in natural systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dehalogenation Activities and Distribution of Reductive Dehalogenase Homologous Genes in Marine Subsurface Sediments▿ †

PubMed Central

Futagami, Taiki; Morono, Yuki; Terada, Takeshi; Kaksonen, Anna H.; Inagaki, Fumio

2009-01-01

Halogenated organic compounds serve as terminal electron acceptors for anaerobic respiration in a diverse range of microorganisms. Here, we report on the widespread distribution and diversity of reductive dehalogenase homologous (rdhA) genes in marine subsurface sediments. A total of 32 putative rdhA phylotypes were detected in sediments from the southeast Pacific off Peru, the eastern equatorial Pacific, the Juan de Fuca Ridge flank off Oregon, and the northwest Pacific off Japan, collected at a maximum depth of 358 m below the seafloor. In addition, significant dehalogenation activity involving 2,4,6-tribromophenol and trichloroethene was observed in sediment slurry from the Nankai Trough Forearc Basin. These results suggest that dehalorespiration is an important energy-yielding pathway in the subseafloor microbial ecosystem. PMID:19749069

Modeling the effects of sodium chloride on degradation of chloramphenicol in aquaculture pond sediment.

PubMed

Chien, Y H; Lai, H T; Liu, S M

1999-10-01

Sodium chloride was added to aquaculture pond sediment to determine effects of different salinities on degradation of chloramphenicol (CM). In this experiment, freshwater (0 ppt salinity) eel pond sediment slurries (10% w/v) were amended with sodium chloride to obtain salinities of 12, 24 and 36 ppt. There were no significant differences in sorption rate either between aerobic and anaerobic conditions or among various salinities. Degradation of CM fitted well to the decaying exponential curve. The degradation rates under anaerobic conditions were significantly greater than those under aerobic conditions. As salinity increased, the degradation rates decreased under both aerobic and anaerobic conditions. The differences in degradation rates either between aerobic and anaerobic conditions or among various salinities were attributed to the effects of microbial activities under different environments.

Characterizing the capacity of hyporheic sediments to attenuate groundwater nitrate loads by adsorption.

PubMed

Meghdadi, Aminreza

2018-05-02

Nitrate has been recognized as a global threat to environmental health. In this regard, the hyporheic zone (saturated media beneath and adjacent to the stream bed) plays a crucial role in attenuating groundwater nitrate, prior to discharge into surface water. While different nitrate removal pathways have been investigated over recent decades, the adsorption capacity of hyporheic sediments under natural conditions has not yet been identified. In this study, the natural attenuation capacity of the hyporheic-sediments of the Ghezel-Ozan River, located in the north-west of Iran, was determined. The sampled sediments (from 1 m below the stream bed) were characterized via XRD, FT-IR, BET, SEM, BJH, and Zeta potential. Nitrate adsorption was evaluated using a batch experiment with hyporheic pore-water from each study site. The study was performed in the hyporheic sediments of two morphologically different zones, including Z 1 located in the parafluvial zone having the clay sediment texture (57.8% clay) with smectite/Illite mixed layer clay type and Z 2 located in the river confluence area containing silty clay sediment texture (47.6% clay) with smectite/kaolinite mixed layer clay type. Data obtained from the batch experiment were subjected to pseudo-first order, pseudo-second order, intra-particle diffusion, and Elovich mass transfer kinetic models to characterize the nitrate adsorption mechanism. Furthermore, to replicate nitrate removal efficiencies of the hyporheic sediments under natural conditions, the sampled hyporheic pore-waters were applied as initial solutions to run the batch experiment. The results of the artificial nitrate solution correlated well with pseudo-second order (R 2 >95%; in both Z 1 and Z 2 ) and maximum removal efficiencies of 85.3% and 71.2% (adsorbent dosage 90 g/L, pH = 5.5, initial adsorbate concentration of 90 mg/L) were achieved in Z 1 and Z 2 , respectively. The results of the nitrate adsorption analysis revealed that the nitrate removal efficiencies varied from 17.24 ± 1.86% in Z 1 during the wet season to 28.13 ± 0.89% in Z 2 during the dry season. The results obtained by this study yielded strong evidence of the potential of hyporheic sediments to remove nitrate from an aqueous environment with great efficiency. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

Size characterization of inclusion bodies by sedimentation field-flow fractionation

PubMed Central

Margreiter, Gerd; Messner, Paul; Caldwell, Karin D.; Bayer, Karl

2015-01-01

Sedimentation field-flow fractionation (sedFFF) was evaluated to characterize the size of Δ(4–23)TEM-β-lactamase inclusion bodies (IBs) overexpressed in fed-batch cultivations of Escherichia coli. Heterologous Δ(4–23)TEM-β-lactamase protein formed different sizes of IBs, depending upon the induction conditions. In the early phases of recombinant protein expression, induced with low concentrations of IPTG (isopropyl-β-d-thiogalactoside), IB masses were larger than expected and showed heterogeneous size distributions. During cultivation, IB sizes showed a Gaussian distribution and reached a broad range by the end of the fed-batch cultivations. The obtained result proved the aptitude of sedFFF to rapidly assess the size distribution of IBs in a culture. PMID:18760314

SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELMINARY DESIGN HAZARD AND OPERABILITY STUDY

DOE Office of Scientific and Technical Information (OSTI.GOV)

CARRO CA

2011-07-15

This Hazard and Operability (HAZOP) study addresses the Sludge Treatment Project (STP) Engineered Container Retrieval and Transfer System (ECRTS) preliminary design for retrieving sludge from underwater engineered containers located in the 105-K West (KW) Basin, transferring the sludge as a sludge-water slurry (hereafter referred to as 'slurry') to a Sludge Transport and Storage Container (STSC) located in a Modified KW Basin Annex, and preparing the STSC for transport to T Plant using the Sludge Transport System (STS). There are six, underwater engineered containers located in the KW Basin that, at the time of sludge retrieval, will contain an estimated volumemore » of 5.2 m{sup 3} of KW Basin floor and pit sludge, 18.4 m{sup 3} of 105-K East (KE) Basin floor, pit, and canister sludge, and 3.5 m{sup 3} of settler tank sludge. The KE and KW Basin sludge consists of fuel corrosion products (including metallic uranium, and fission and activation products), small fuel fragments, iron and aluminum oxide, sand, dirt, operational debris, and biological debris. The settler tank sludge consists of sludge generated by the washing of KE and KW Basin fuel in the Primary Clean Machine. A detailed description of the origin of sludge and its chemical and physical characteristics can be found in HNF-41051, Preliminary STP Container and Settler Sludge Process System Description and Material Balance. In summary, the ECRTS retrieves sludge from the engineered containers and hydraulically transfers it as a slurry into an STSC positioned within a trailer-mounted STS cask located in a Modified KW Basin Annex. The slurry is allowed to settle within the STSC to concentrate the solids and clarify the supernate. After a prescribed settling period the supernate is decanted. The decanted supernate is filtered through a sand filter and returned to the basin. Subsequent batches of slurry are added to the STSC, settled, and excess supernate removed until the prescribed quantity of sludge is collected. The sand filter is then backwashed into the STSC. The STSC and STS cask are then inerted and transported to T Plant.« less

Reclamation of grey water for non-potable purposes using pilot-scale solar photocatalytic tubular reactors.

PubMed

Saran, Sarangapany; Arunkumar, Patchaiyappan; Manjari, Gangarapu; Devipriya, Suja P

2018-05-05

Application of pilot-scale slurry-type tubular photocatalytic reactor was tested for the decentralized treatment of actual grey water. The reactors were fabricated by reusing the locally available materials at low cost, operated in batch recycle mode with 25 L of grey water. The influence of operational parameters such as catalysts' concentration, initial slurry pH and addition of H 2 O 2 on COD abatement were optimized. The results show that Ag-decorated TiO 2 showed a two-fold increase in COD abatement than did pure TiO 2 . Better COD abatement was observed under acidic conditions, and addition of H 2 O 2 significantly increases the rate of COD abatement. Within 2 h, 99% COD abatement was observed when the reactor was operated with optimum operational conditions. Silver ion lixiviate was also monitored during the experiment and is five times less than the permissible limits. The catalyst shows good stability even after five cycles without much loss in its photocatalytic activity. The results clearly reveal that pilot-scale slurry tubular solar photocatalytic reactors could be used as a cost-effective method to treat grey water and the resulting clean water could be reused for various non-potable purposes, thus conserving precious water resource. This study favours decentralized grey water treatment and possible scaling up of solar photocatalytic reactor using locally available materials for the potential reuse of treated water.

Effects of Sterilization on the Physico-Chemical Properties of Natural Sediments From the Oak Ridge Reservation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bank, T.L.; Kukkadapu, R.K.; Madden, A.S.

2009-04-29

Batch U(VI) sorption/reduction experiments were completed on sterilized and non-sterilized sediment samples to elucidate biological and geochemical reduction mechanisms. Results from X-ray absorption near-edge structure (XANES) spectroscopy revealed that {gamma}-sterilized sediments were actually better sorbents of U(VI), despite the absence of any measurable biological activity. These results indicate that {gamma}-irradiation induced significant physico-chemical changes in the sediment which is contrary to numerous other studies identifying {gamma}-sterilization as an effective and minimally invasive technique. To identify the extent and method of alteration of the soil as a result of {gamma}-sterilization, untreated soil samples, physically separated size fractions, and chemically extracted fractionsmore » of the soil were analyzed pre- and post-sterilization. The effects of sterilization on mineralogy, pH, natural organic matter (NOM), cation exchange capacity (CEC), and iron oxidation state were determined. Results indicated that major mineralogy of the clay and whole sediment samples was unchanged. Sediment pH decreased only slightly with {gamma}-irradiation; however, irradiation produced a significant decrease in CEC of the untreated sediments and affected both the organic and inorganic fractions. Moessbauer spectra of non-sterile and {gamma}-sterilized sediments measured more reduced iron present in {gamma}-sterilized sediments compared to non-sterile samples. Our results suggest that sterilization by {gamma}-irradiation induced iron reduction that may have increased the sorption and/or reduction of U(VI) onto these sediments. However, Moessbauer and batch sorption data are somewhat contradictory, the former indicates that the iron oxide or iron hydroxide minerals are more significantly reduced while the later indicates that reduced clay minerals account for greater sorption of U(VI).« less

Effects of gamma-sterilization on the physicochemical properties of natural sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bank, Tracy L; Madden, Andrew; Baldwin, Mark E

2008-06-01

Batch U(VI) sorption/reduction experiments were completed on sterilized and non-sterilized sediment samples to elucidate biological and geochemical reduction mechanisms. Results from X-ray absorption near-edge structure (XANES) spectroscopy revealed that {gamma}-sterilized sediments were actually better sorbents of U(VI), despite the absence of any measurable biological activity. These results indicate that {gamma}-irradiation induced significant physico-chemical changes in the sediment which is contrary to numerous other studies identifying {gamma}-sterilization as an effective and minimally invasive technique. To identify the extent and method of alteration of the soil as a result of {gamma}-sterilization, untreated soil samples, physically separated size fractions, and chemically extracted fractionsmore » of the soil were analyzed pre- and post-sterilization. The effects of sterilization on mineralogy, pH, natural organic matter (NOM), cation exchange capacity (CEC), and iron oxidation state were determined. Results indicated that major mineralogy of the clay and whole sediment samples was unchanged. Sediment pH decreased only slightly with {gamma}-irradiation; however, irradiation produced a significant decrease in CEC of the untreated sediments and affected both the organic and inorganic fractions. Moessbauer spectra of non-sterile and {gamma}-sterilized sediments measured more reduced iron present in {gamma}-sterilized sediments compared to non-sterile samples. Our results suggest that sterilization by {gamma}-irradiation induced iron reduction that may have increased the sorption and/or reduction of U(VI) onto these sediments. However, Moessbauer and batch sorption data are somewhat contradictory, the former indicates that the iron oxide or iron hydroxide minerals are more significantly reduced while the later indicates that reduced clay minerals account for greater sorption of U(VI).« less

Coupling fractionation and batch desorption to understand arsenic and fluoride co-contamination in the aquifer system.

PubMed

Kumar, Manish; Das, Nilotpal; Goswami, Ritusmita; Sarma, Kali Prasad; Bhattacharya, Prosun; Ramanathan, A L

2016-12-01

The present work is an attempt to study As and F+ coevality using laboratory based assays which couples fractionation and batch dissolution experiments. Sequential extraction procedure (SEP) resulting into five "operationally defined phases", was performed on sediment and soil samples collected from the Brahmaputra flood plains, Assam, India. High correlation between the Fe (hydr)oxide fraction and total As content of the soil/sediment sample indicates the involvement of Fe (hydr)oxides as the principal source of As. F - being an anion has high potential to be sorbed onto positively charged surfaces. Findings of the SEP were used to design the batch desorption experiments by controlling the Fe (hydr)oxide content of the soil/sediment. Desorption of As and F - was observed under acidic, neutral and alkaline pH from untreated and Fe (hydr)oxide removed samples. Highest amount of As and F - were found to be released from untreated samples under alkaline pH, while the amount leached from samples with no Fe (hydr)oxide was low. The study showed that the Fe (hydr)oxide fraction commonly found in the soils and sediments, had high affinity for negatively charged species like F - oxyanions of As, AsO 4 3- (arsenate) and AsO 3 3- (arsenite). Fe (hydr)oxide fraction was found to play the major role in co-evolution of As and F - . Two sorption coefficients were proposed based on easily leachable fraction and As present in the groundwater of sampling location for understanding of contamination vulnerability from the leaching. Copyright © 2016 Elsevier Ltd. All rights reserved.

Release of elements to natural water from sediments of Lake Roosevelt, Washington, USA

USGS Publications Warehouse

Paulson, Anthony J.; Cox, Stephen E.

2007-01-01

Reservoir sediments from Lake Roosevelt (WA, USA) that were contaminated with smelter waste discharged into the Columbia River (BC, Canada) were examined using three measures of elemental release reflecting varying degrees of physical mixing and time scales. Aqueous concentrations of Cd, Cu, Pb, and Zn in the interstitial water of reservoir sediments, in the gently stirred overlying waters of incubated sediment cores, and in supernatants of aggressively tumbled slurries of reservoir sediments generally were higher than the concentrations from a reference site. When compared to chronic water-quality criteria, all three measures of release suggest that slag-contaminated sediments near the U.S.-Canadian border are potentially toxic as a result of Cu release and Pb release in two of the three measures. All three measures of Cd release suggest potential toxicity for one site farther down the reservoir, probably contaminated as a result of transport and adsorption of Cd from smelter liquid waste. Releases of Zn and As did not appear to be potentially toxic. Carbonate geochemistry indirectly affects the potential toxicity by increasing water hardness.

Determination of variables in the prediction of strontium distribution coefficients for selected sediments

USGS Publications Warehouse

Pace, M.N.; Rosentreter, J.J.; Bartholomay, R.C.

2001-01-01

Idaho State University and the US Geological Survey, in cooperation with the US Department of Energy, conducted a study to determine and evaluate strontium distribution coefficients (Kds) of subsurface materials at the Idaho National Engineering and Environmental Laboratory (INEEL). The Kds were determined to aid in assessing the variability of strontium Kds and their effects on chemical transport of strontium-90 in the Snake River Plain aquifer system. Data from batch experiments done to determine strontium Kds of five sediment-infill samples and six standard reference material samples were analyzed by using multiple linear regression analysis and the stepwise variable-selection method in the statistical program, Statistical Product and Service Solutions, to derive an equation of variables that can be used to predict strontium Kds of sediment-infill samples. The sediment-infill samples were from basalt vesicles and fractures from a selected core at the INEEL; strontium Kds ranged from ???201 to 356 ml g-1. The standard material samples consisted of clay minerals and calcite. The statistical analyses of the batch-experiment results showed that the amount of strontium in the initial solution, the amount of manganese oxide in the sample material, and the amount of potassium in the initial solution are the most important variables in predicting strontium Kds of sediment-infill samples.

Upscaling of U(VI) Desorption and Transport from Decimeter-Scale Heterogeneity to Plume-Scale Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtis, Gary P.; Kohler, Matthias; Kannappan, Ramakrishnan

2015-02-24

Scientifically defensible predictions of field scale U(VI) transport in groundwater requires an understanding of key processes at multiple scales. These scales range from smaller than the sediment grain scale (less than 10 μm) to as large as the field scale which can extend over several kilometers. The key processes that need to be considered include both geochemical reactions in solution and at sediment surfaces as well as physical transport processes including advection, dispersion, and pore-scale diffusion. The research summarized in this report includes both experimental and modeling results in batch, column and tracer tests. The objectives of this research weremore » to: (1) quantify the rates of U(VI) desorption from sediments acquired from a uranium contaminated aquifer in batch experiments;(2) quantify rates of U(VI) desorption in column experiments with variable chemical conditions, and(3) quantify nonreactive tracer and U(VI) transport in field tests.« less

Temperature-driven decoupling of key phases of organic matter degradation in marine sediments.

PubMed

Weston, Nathaniel B; Joye, Samantha B

2005-11-22

The long-term burial of organic carbon in sediments results in the net accumulation of oxygen in the atmosphere, thereby mediating the redox state of the Earth's biosphere and atmosphere. Sediment microbial activity plays a major role in determining whether particulate organic carbon is recycled or buried. A diverse consortium of microorganisms that hydrolyze, ferment, and terminally oxidize organic compounds mediates anaerobic organic matter mineralization in anoxic sediments. Variable temperature regulation of the sequential processes, leading from the breakdown of complex particulate organic carbon to the production and subsequent consumption of labile, low-molecular weight, dissolved intermediates, could play a key role in controlling rates of overall organic carbon mineralization. We examined sediment organic carbon cycling in a sediment slurry and in flow through bioreactor experiments. The data show a variable temperature response of the microbial functional groups mediating organic matter mineralization in anoxic marine sediments, resulting in the temperature-driven decoupling of the production and consumption of organic intermediates. This temperature-driven decoupling leads to the accumulation of labile, low-molecular weight, dissolved organic carbon at low temperatures and low-molecular weight dissolved organic carbon limitation of terminal metabolism at higher temperatures.

Hydrated calcareous oil-shale ash as potential filter media for phosphorus removal in constructed wetlands.

PubMed

Kaasik, Ago; Vohla, Christina; Mõtlep, Riho; Mander, Ulo; Kirsimäe, Kalle

2008-02-01

The P-retention in hydrated calcareous ash sediment from oil-shale burning thermal power plants in Estonia was studied. Batch experiments indicate good (up to 65 mg P g(-1)) P-binding capacity of the hydrated oil-shale ash sediment, with a removal effectiveness of 67-85%. The high phosphorus sorption potential of hydrated oil-shale ash is considered to be due to the high content of reactive Ca-minerals, of which ettringite Ca6Al2(SO4)3(OH)12.26H2O and portlandite Ca(OH)2 are the most important. The equilibrium dissolution of ettringite provides free calcium ions that act as stable nuclei for phosphate precipitation. The precipitation mechanism of phosphorus removal in hydrated ash plateau sediment is suggested by Ca-phosphate formation in batch experiments at different P-loadings. Treatment with a P-containing solution causes partial-to-complete dissolution of ettringite and portlandite, and precipitation of Ca-carbonate and Ca-phosphate phases, which was confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM)-EDS studies. Thus, the hydrated oil-shale ash sediment can be considered as a potential filtration material for P removal in constructed wetlands for wastewater treatment.

Evaluating Impacts of CO2 Gas Intrusion Into a Confined Sandstone aquifer: Experimental Results

DOE PAGES

Qafoku, Nikolla; Lawter, Amanda R.; Shao, Hongbo; ...

2014-12-31

Deep subsurface storage and sequestration of CO2 has been identified as a potential mitigation technique for rising atmospheric CO2 concentrations. Sequestered CO2 represents a potential risk to overlying aquifers if the CO2 leaks from the deep storage reservoir. Experimental and modeling work is required to evaluate potential risks to groundwater quality and develop a systematic understanding of how CO2 leakage may cause important changes in aquifer chemistry and mineralogy by promoting dissolution/precipitation, adsorption/desorption, and redox reactions. Sediments from the High Plains aquifer in Kansas, United States, were used in this investigation, which is part of the National Risk Assessment Partnershipmore » Program sponsored by the US Department of Energy. This aquifer was selected to be representative of consolidated sand and gravel/sandstone aquifers overlying potential CO2 sequestration repositories within the continental US. In this paper, we present results from batch experiments conducted at room temperature and atmospheric pressure with four High Plains aquifer sediments. Batch experiments simulate sudden, fast, and short-lived releases of the CO2 gas as would occur in the case of well failure during injection. Time-dependent release of major, minor, and trace elements were determined by analyzing the contacting solutions. Characterization studies demonstrated that the High Plains aquifer sediments were abundant in quartz and feldspars, and contained about 15 to 20 wt% montmorillonite and up to 5 wt% micas. Some of the High Plains aquifer sediments contained no calcite, while others had up to about 7 wt% calcite. The strong acid extraction tests confirmed that in addition to the usual elements present in most soils, rocks, and sediments, the High Plains aquifer sediments had appreciable amounts of As, Cd, Pb, Cu, and occasionally Zn, which potentially may be mobilized from the solid to the aqueous phase during or after exposure to CO2. However, the results from the batch experiments showed that the High Plains sediments mobilized only low concentrations of trace elements (potential contaminants), which were detected occasionally in the aqueous phase during these experiments. Importantly, these occurrences were more frequent in the calcite-free sediment. Results from these investigations provide useful information to support site selection, risk assessment, and public education efforts associated with geological CO2 storage and sequestration.« less

U(VI) adsorption on aquifer sediments at the Hanford Site.

PubMed

Um, Wooyong; Serne, R Jeffrey; Brown, Christopher F; Last, George V

2007-08-15

Aquifer sediments collected via split-spoon sampling in two new groundwater wells in the 200-UP-1 operable unit at the Hanford Site were characterized and showed typical Ringold Unit E Formation properties dominated by gravel and sand. High iron-oxide content in Fe oxide/clay coatings caused the highest U(VI) adsorption as quantified by batch K(d) values, indicating iron oxides are the key solid adsorbent in the 200-UP-1 sediments that affect U(VI) fate and mobility. Even though U(VI) adsorption on the gravel-sized fraction of the sediments is considered to be negligible, careful characterization should be conducted to determine U(VI) adsorption on gravel, because of presence of Fe oxides coatings and diffusion-controlled adsorption into the gravel particles' interior surfaces. A linear adsorption isotherm was observed up to 10(-6) M (238 microg/L) of total U(VI) concentration in batch U(VI) adsorption tests with varying total U(VI) concentrations in spiked groundwater. U(VI) adsorption decreased with increasing concentrations of dissolved carbonate, because strong anionic aqueous uranium-carbonate complexes formed at high pH and high alkalinity conditions. Noticeable uranium desorption hysteresis was observed in a flow-through column experiment, suggesting that desorption K(d) values for aged uranium-contaminated sediments at the Hanford Site can be larger than adsorption K(d) values determined in short-term laboratory experiments and slow uranium release from contaminated sediments into the groundwater is expected.

Exploring the controls of soil biogeochemistry in a restored coastal wetland using object-oriented computer simulations of uptake kinetics and thermodynamic optimization in batch reactors

NASA Astrophysics Data System (ADS)

Payn, R. A.; Helton, A. M.; Poole, G.; Izurieta, C.; Bernhardt, E. S.; Burgin, A. J.

2012-12-01

Many hypotheses have been proposed to predict patterns of biogeochemical redox reactions based on the availability of electron donors and acceptors and the thermodynamic theory of chemistry. Our objective was to develop a computer model that would allow us to test various alternatives of these hypotheses against data gathered from soil slurry batch reactors, experimental soil perfusion cores, and in situ soil profile observations from the restored Timberlake Wetland in coastal North Carolina, USA. Software requirements to meet this objective included the ability to rapidly develop and compare different hypothetical formulations of kinetic and thermodynamic theory, and the ability to easily change the list of potential biogeochemical reactions used in the optimization scheme. For future work, we also required an object pattern that could easily be coupled with an existing soil hydrologic model. These requirements were met using Network Exchange Objects (NEO), our recently developed object-oriented distributed modeling framework that facilitates simulations of multiple interacting currencies moving through network-based systems. An initial implementation of the object pattern was developed in NEO based on maximizing growth of the microbial community from available dissolved organic carbon. We then used this implementation to build a modeling system for comparing results across multiple simulated batch reactors with varied initial solute concentrations, varied biogeochemical parameters, or varied optimization schemes. Among heterotrophic aerobic and anaerobic reactions, we have found that this model reasonably predicts the use of terminal electron acceptors in simulated batch reactors, where reactions with higher energy yields occur before reactions with lower energy yields. However, among the aerobic reactions, we have also found this model predicts dominance of chemoautotrophs (e.g., nitrifiers) when their electron donor (e.g., ammonium) is abundant, despite the fact that aerobic respiration produces a higher energy yield from the available dissolved oxygen. This suggests that incorporation of an alternative hypothesis, such as a maximum efficiency model, may be necessary to explain an observation of substantial aerobic respiration occurring in the presence of high ammonium and oxygen concentrations. We are parameterizing and testing this model based on results from batch reactor experiments that have treated soil slurries with a full factorial combination of various levels of reactive solutes found in freshwater (e.g., nitrate) and seawater (e.g., sulfate). Initial comparisons suggest that the model may need to account for the biogeochemical reactivity of iron and the potential physical influence of salt to properly describe variability in the biogeochemistry of Timberlake soils. Comparisons of these evolving models with field-derived data from soils will ultimately reveal how thermodynamic theory may be used to explain the evolution of nutrient retention and greenhouse gas emission in the Timberlake Wetland, where nutrient behavior is changing after restoration from agricultural land use and where inputs of brackish water are expected to increase due to sea level rise.

Arsenic release from shallow aquifers of the Hetao basin, Inner Mongolia: evidence from bacterial community in aquifer sediments and groundwater.

PubMed

Li, Yuan; Guo, Huaming; Hao, Chunbo

2014-12-01

Indigenous microbes play crucial roles in arsenic mobilization in high arsenic groundwater systems. Databases concerning the presence and the activity of microbial communities are very useful in evaluating the potential of microbe-mediated arsenic mobilization in shallow aquifers hosting high arsenic groundwater. This study characterized microbial communities in groundwaters at different depths with different arsenic concentrations by DGGE and one sediment by 16S rRNA gene clone library, and evaluated arsenic mobilization in microcosm batches with the presence of indigenous bacteria. DGGE fingerprints revealed that the community structure changed substantially with depth at the same location. It indicated that a relatively higher bacterial diversity was present in the groundwater sample with lower arsenic concentration. Sequence analysis of 16S rRNA gene demonstrated that the sediment bacteria mainly belonged to Pseudomonas, Dietzia and Rhodococcus, which have been widely found in aquifer systems. Additionally, NO3(-)-reducing bacteria Pseudomonas sp. was the largest group, followed by Fe(III)-reducing, SO4(2-)-reducing and As(V)-reducing bacteria in the sediment sample. These anaerobic bacteria used the specific oxyanions as electron acceptor and played a significant role in reductive dissolution of Fe oxide minerals, reduction of As(V), and release of arsenic from sediments into groundwater. Microcosm experiments, using intact aquifer sediments, showed that arsenic release and Fe(III) reduction were microbially mediated in the presence of indigenous bacteria. High arsenic concentration was also observed in the batch without amendment of organic carbon, demonstrating that the natural organic matter in sediments was the potential electron donor for microbially mediated arsenic release from these aquifer sediments.

Stochastic Modelling of the Hydraulic Anisotropy of Ash Impoundment Sediment

NASA Astrophysics Data System (ADS)

Slávik, Ivan

2017-12-01

In the case reported here the impoundments of a 400 MW coal heated power plant with an annual production of about 1.5 million tons of fuel ash are of the cross-valley type, operated by the simple and cheap „upstream method”. The aim of the research was to determine overall and local values of the permeability in horizontal as well as in vertical direction and the anisotropy of the thin-layered sedimented ash. The coal ashes are hydraulically transported through pipelines in form of a slurry and periodically floated on the beach of the impoundment. The ashes are deposited in the form of a thin-layered sediment, with random alternation of layers with a coarser or finer granularity. The ash impoundment sediment is anthropogenic sediment with horizontally laminated texture. Therefore, the sediment is anisotropic from the viewpoint of water seepage. The knowledge of the permeability and the seepage anisotropy of the sediment is a basic requirement for the design of an appropriate dewatering system. The seepage anisotropy of the ash sediment has been checked by means of stochastic modelling, based on the correlation between the effective grain diameter and the coefficient of permeability of the ash: the effective grain diameter and the thickness of individual layers have been proposed to be random events.

Kinetics of hydrophobic organic contaminant extraction from sediment by granular activated carbon.

PubMed

Rakowska, M I; Kupryianchyk, D; Smit, M P J; Koelmans, A A; Grotenhuis, J T C; Rijnaarts, H H M

2014-03-15

Ex situ solid phase extraction with granular activated carbon (GAC) is a promising technique to remediate contaminated sediments. The methods' efficiency depends on the rate by which contaminants are transferred from the sediment to the surface of GAC. Here, we derive kinetic parameters for extraction of polycyclic aromatic hydrocarbons (PAH) from sediment by GAC, using a first-order multi-compartment kinetic model. The parameters were obtained by modeling sediment-GAC exchange kinetic data following a tiered model calibration approach. First, parameters for PAH desorption from sediment were calibrated using data from systems with 50% (by weight) GAC acting as an infinite sink. Second, the estimated parameters were used as fixed input to obtain GAC uptake kinetic parameters in sediment slurries with 4% GAC, representing the ex situ remediation scenario. PAH uptake rate constants (kGAC) by GAC ranged from 0.44 to 0.0005 d(-1), whereas GAC sorption coefficients (KGAC) ranged from 10(5.57) to 10(8.57) L kg(-1). These values are the first provided for GAC in the presence of sediment and show that ex situ extraction with GAC is sufficiently fast and effective to reduce the risks of the most available PAHs among those studied, such as fluorene, phenanthrene and anthracene. Copyright © 2013 Elsevier Ltd. All rights reserved.

Transformation and fate of nitrate near the sediment-water interface of Copano Bay

NASA Astrophysics Data System (ADS)

Hou, Lijun; Liu, Min; Carini, Stephen A.; Gardner, Wayne S.

2012-03-01

This study investigated potential transformation processes and fates of nitrate at the sediment-water interface of Copano Bay during a period of drought by conducting continuous-flow and slurry experiments combined with a 15NO3- addition technique. Rates of 15NO3--based denitrification, anaerobic ammonium oxidation (ANAMMOX) and potential dissimilatory nitrate reduction to ammonium (DNRA) were in the range of 27.7-40.1, 0.26-1.6 and 1.4-3.8 μmol 15N m-2 h-1, respectively. Compared with the total 15NO3-fluxes into sediments, dissimilatory processes contributed 29-49% to loss of the spiked 15NO3-. Based on the mass balance of 15NO3-, microbial assimilation was estimated to consume about 50-70% of the added 15NO3-, indicating that most of nitrate was incorporated by microorganisms in this N-limiting system. In addition, significant correlations of nitrate transformation rates with sediment characteristics reflect that the depth related behaviors of nitrate transformations in core sediments were coupled strongly to organic matter, iron (Fe) and sulfur (S) cycles.

Process and system for treating waste water

DOEpatents

Olesen, Douglas E.; Shuckrow, Alan J.

1978-01-01

A process of treating raw or primary waste water using a powdered, activated carbon/aerated biological treatment system is disclosed. Effluent turbidities less than 2 JTU (Jackson turbidity units), zero TOC (total organic carbon) and in the range of 10 mg/l COD (chemical oxygen demand) can be obtained. An influent stream of raw or primary waste water is contacted with an acidified, powdered, activated carbon/alum mixture. Lime is then added to the slurry to raise the pH to about 7.0. A polyelectrolyte flocculant is added to the slurry followed by a flocculation period -- then sedimentation and filtration. The separated solids (sludge) are aerated in a stabilization sludge basin and a portion thereof recycled to an aerated contact basin for mixing with the influent waste water stream prior to or after contact of the influent stream with the powdered, activated carbon/alum mixture.

Leachate Testing of Hamlet City Lake, North Carolina, Sediment

DTIC Science & Technology

1992-11-01

release; distribution is unlimited. 13. ABSTRACT (Maximum 200 words) Sediment leaching studies of Hamlet City Lake, Hamlet, NC, were conducted in...laboratories at the U.S. Army Engineer Waterways Experiment Station. The pur- pose of these studies was to provide quantitative information on the...conditions similar to landfarming. The study involved three elements: batch leach tests, column leach tests, and simulations using the Hydrologic

Uncertainty and variability in laboratory derived sorption parameters of sediments from a uranium in situ recovery site

NASA Astrophysics Data System (ADS)

Dangelmayr, Martin A.; Reimus, Paul W.; Johnson, Raymond H.; Clay, James T.; Stone, James J.

2018-06-01

This research assesses the ability of a GC SCM to simulate uranium transport under variable geochemical conditions typically encountered at uranium in-situ recovery (ISR) sites. Sediment was taken from a monitoring well at the SRH site at depths 192 and 193 m below ground and characterized by XRD, XRF, TOC, and BET. Duplicate column studies on the different sediment depths, were flushed with synthesized restoration waters at two different alkalinities (160 mg/l CaCO3 and 360 mg/l CaCO3) to study the effect of alkalinity on uranium mobility. Uranium breakthrough occurred 25% - 30% earlier in columns with 360 mg/l CaCO3 over columns fed with 160 mg/l CaCO3 influent water. A parameter estimation program (PEST) was coupled to PHREEQC to derive site densities from experimental data. Significant parameter fittings were produced for all models, demonstrating that the GC SCM approach can model the impact of carbonate on uranium in flow systems. Derived site densities for the two sediment depths were between 141 and 178 μmol-sites/kg-soil, demonstrating similar sorption capacities despite heterogeneity in sediment mineralogy. Model sensitivity to alkalinity and pH was shown to be moderate compared to fitted site densities, when calcite saturation was allowed to equilibrate. Calcite kinetics emerged as a potential source of error when fitting parameters in flow conditions. Fitted results were compared to data from previous batch and column studies completed on sediments from the Smith-Ranch Highland (SRH) site, to assess variability in derived parameters. Parameters from batch experiments were lower by a factor of 1.1 to 3.4 compared to column studies completed on the same sediments. The difference was attributed to errors in solid-solution ratios and the impact of calcite dissolution in batch experiments. Column studies conducted at two different laboratories showed almost an order of magnitude difference in fitted site densities suggesting that experimental methodology may play a bigger role in column sorption behavior than actual sediment heterogeneity. Our results demonstrate the necessity for ISR sites to remove residual pCO2 and equilibrate restoration water with background geochemistry to reduce uranium mobility. In addition, the observed variability between fitted parameters on the same sediments highlights the need to provide standardized guidelines and methodology for regulators and industry when the GC SCM approach is used for ISR risk assessments.

Uncertainty and variability in laboratory derived sorption parameters of sediments from a uranium in situ recovery site.

PubMed

Dangelmayr, Martin A; Reimus, Paul W; Johnson, Raymond H; Clay, James T; Stone, James J

2018-06-01

This research assesses the ability of a GC SCM to simulate uranium transport under variable geochemical conditions typically encountered at uranium in-situ recovery (ISR) sites. Sediment was taken from a monitoring well at the SRH site at depths 192 and 193 m below ground and characterized by XRD, XRF, TOC, and BET. Duplicate column studies on the different sediment depths, were flushed with synthesized restoration waters at two different alkalinities (160 mg/l CaCO 3 and 360 mg/l CaCO 3 ) to study the effect of alkalinity on uranium mobility. Uranium breakthrough occurred 25% - 30% earlier in columns with 360 mg/l CaCO 3 over columns fed with 160 mg/l CaCO 3 influent water. A parameter estimation program (PEST) was coupled to PHREEQC to derive site densities from experimental data. Significant parameter fittings were produced for all models, demonstrating that the GC SCM approach can model the impact of carbonate on uranium in flow systems. Derived site densities for the two sediment depths were between 141 and 178 μmol-sites/kg-soil, demonstrating similar sorption capacities despite heterogeneity in sediment mineralogy. Model sensitivity to alkalinity and pH was shown to be moderate compared to fitted site densities, when calcite saturation was allowed to equilibrate. Calcite kinetics emerged as a potential source of error when fitting parameters in flow conditions. Fitted results were compared to data from previous batch and column studies completed on sediments from the Smith-Ranch Highland (SRH) site, to assess variability in derived parameters. Parameters from batch experiments were lower by a factor of 1.1 to 3.4 compared to column studies completed on the same sediments. The difference was attributed to errors in solid-solution ratios and the impact of calcite dissolution in batch experiments. Column studies conducted at two different laboratories showed almost an order of magnitude difference in fitted site densities suggesting that experimental methodology may play a bigger role in column sorption behavior than actual sediment heterogeneity. Our results demonstrate the necessity for ISR sites to remove residual pCO2 and equilibrate restoration water with background geochemistry to reduce uranium mobility. In addition, the observed variability between fitted parameters on the same sediments highlights the need to provide standardized guidelines and methodology for regulators and industry when the GC SCM approach is used for ISR risk assessments. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of Silica Particle Size of Nuclear Waste-to-Glass Conversion - 17319

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixon, Derek R.; Cutforth, Derek A.; Vanderveer, Bradley J.

The process for converting nuclear waste-to-glass in an electric melter occurs in the cold cap, a crust of reacting solids floating on the glass pool. As the melter feed (a mixture of the nuclear waste and glass forming and modifying additives) heats up in the cold cap, glass-forming reactions ensue, causing the feed matrix to connect, trapping reaction gases to create a foam layer. The foam layer reduces the rate of melting by separating the reacting feed from the melt pool. The size of the silica particle additives in the melter feed affects melt viscosity and, hence, foam stability. Tomore » investigate this effect, seven nuclear waste simulant feeds of a high-level waste were batched as slurries and prepared with dissimilar ranges of silica particle size. Each slurry feed was charged into a laboratory-scale melter (LSM) to produce a cold cap and the propensity of feeds to foam was determined by pressing dried feeds into pellets and monitoring the change of pellet volume in response to heating. Two of these slurries were designed to have dissimilar glass viscosities at 1150°C. In the low temperature region of the cold cap, before the melter feed connects, the feeds without fine silica particles behaved similar to the high viscosity feed as their volume contracted while the feed with silica particles no larger than 5 µm reacted like the low viscosity feed. However, the feed volume similarities reversed as the feed connected and expanded through the foam region of the cold cap.« less

Co-digestion of dairy cattle slurry and industrial meat-processing by-products--effect of ultrasound and hygienization pre-treatments.

PubMed

Luste, Sami; Heinonen-Tanski, Helvi; Luostarinen, Sari

2012-01-01

Anaerobic co-digestion of a mixture of industrial animal by-products (ABP) from meat-processing in conjunction with dairy cattle slurry (mixed in a ratio of 1:3; w.w.) was evaluated at 35 °C focusing on methane production and stabilization. Three pre-treatments were applied (1) digestion with no pre-treatment (control), (2) ultrasound, and (3) thermal hygienization (70 °C, 60 min). Methane production potentials (MPP) of the untreated, ultrasound pre-treated and hygienized feed mixtures were 300, 340, and 360 m(3) CH(4)/t volatile solids (VS) added, as determined in the batch experiments. However, the specific methane productions (SMP) achieved in reactor experiments (hydraulic retention time HRT 21 d, organic loading rate OLR 3.0±0.1 kg VS/m(3) d) were 11±2% (untreated and ultrasound pre-treated) and 22±3% (hygienized) lower than the potentials. Ultrasound with the energy input of 1000 kJ/kg total solids (TS) and hygienization of the ready-made feed were the most suitable pre-treatment modes studied. Copyright © 2011 Elsevier Ltd. All rights reserved.

Biogas from mesophilic anaerobic digestion of cow dung using gelatin as additive

NASA Astrophysics Data System (ADS)

Salam, Bodius; Rahman, Md Mizanur; Sikder, Md Asif R.; Islam, Majedul

2017-06-01

A research work was conducted to investigate the enhanced production ability of biogas from mesophilic anaerobic digestions of cow dung (CD) using gelatin as additive. Five laboratory scale digesters were constructed to digest cow dung, where one set up was used for digestion of cow dung without additive and the other set up were used for digestion with additive. Gelatin additive was added in the slurry of amount 0.29, 0,57, 0.85 and 1.14% (wt.). The digesters were made of glass conical flask of 1-liter capacity each. Cow dung was used 335 gm and water was used 365 gm in each experiment. In the slurry, total solid content was maintained 8% (wt.) for all the observations. The digesters were fed on batch basis. The digesters were operated at ambient temperatures of 26 - 35°C. The total gas yield was obtained about 14.4 L/kg CD for digestion without additive and about 65% more biogas for digestion with 0.29% gelatin additive. The retention time for digestion without additive was 38 days and with additive retention time varied between 24 and 52 days.

Long-term fertilization alters the relative importance of nitrate reduction pathways in salt marsh sediments

NASA Astrophysics Data System (ADS)

Peng, Xuefeng; Ji, Qixing; Angell, John H.; Kearns, Patrick J.; Yang, Hannah J.; Bowen, Jennifer L.; Ward, Bess B.

2016-08-01

Salt marshes provide numerous valuable ecological services. In particular, nitrogen (N) removal in salt marsh sediments alleviates N loading to the coastal ocean. N removal reduces the threat of eutrophication caused by increased N inputs from anthropogenic sources. It is unclear, however, whether chronic nutrient overenrichment alters the capacity of salt marshes to remove anthropogenic N. To assess the effect of nutrient enrichment on N cycling in salt marsh sediments, we examined important N cycle pathways in experimental fertilization plots in a New England salt marsh. We determined rates of nitrification, denitrification, and dissimilatory nitrate reduction to ammonium (DNRA) using sediment slurry incubations with 15N labeled ammonium or nitrate tracers under oxic headspace (20% oxygen/80% helium). Nitrification and denitrification rates were more than tenfold higher in fertilized plots compared to control plots. By contrast, DNRA, which retains N in the system, was high in control plots but not detected in fertilized plots. The relative contribution of DNRA to total nitrate reduction largely depends on the carbon/nitrate ratio in the sediment. These results suggest that long-term fertilization shifts N cycling in salt marsh sediments from predominantly retention to removal.

TANK 40 FINAL SB7B CHEMICAL CHARACTERIZATION RESULTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C.

2012-03-15

A sample of Sludge Batch 7b (SB7b) was taken from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). The SB7b WAPS sample was also analyzed for chemical composition including noble metals and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is currently being fed to the Defense Waste Processing Facility (DWPF) as SB7b. At the Savannah River National Laboratory (SRNL) the 3-L Tank 40 SB7b sample was transferred frommore » the shipping container into a 4-L high density polyethylene bottle and solids were allowed to settle over the weekend. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 558 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon{reg_sign} vessels and four with NaOH/Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Two Analytical Reference Glass - 1 (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 mL with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma - atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma - mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB7b supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH{sup -}/other base, total inorganic carbon/total organic carbon (TIC/TOC) analyses, and Cs-137 gamma scan. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH{sup -}/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the Tank 40 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method developed by SRNL AD and previously described. The following conclusions were drawn from the analytical results reported here: (1) The ratios of the major elements for the SB7b WAPS sample are different from those measured for the SB7a WAPS sample. There is less Al and Mn relative to Fe than the previous sludge batch. (2) The elemental composition of this sample and the analyses conducted here are reasonable and consistent with DWPF batch data measurements in light of DWPF pre-sample concentration and SRAT product heel contributions to the DWPF SRAT receipt analyses. The element ratios for Al/Fe, Ca/Fe, Mn/Fe, and U/Fe agree within 10% between this work and the DWPF Sludge Receipt and Adjustment Tank (SRAT) receipt analyses. (3) Sulfur in the SB7b WAPS sample is 82% soluble, slightly less than results reported for SB3, SB4, and SB6 samples but unlike the 50% insoluble sulfur observed in the SB5 WAPS sample. In addition, 23% of the soluble sulfur is not present as sulfate in SB7b. (4) The average activities of the fissile isotopes of interest in the SB7b WAPS sample are (in {mu}Ci/g of total dried solids): 4.22E-02 U-233, 6.12E-04 U-235, 1.08E+01 Pu-239, and 5.09E+01 Pu-241. The full radionuclide composition will be reported in a future document. (5) The fission product noble metal and Ag concentrations appear to have largely peaked in previous DWPF sludge batches, with the exception of Ru, which still shows a slight increase in SB7b.« less

Development of a new model for batch sedimentation and application to secondary settling tanks design.

PubMed

Karamisheva, Ralica D; Islam, M A

2005-01-01

Assuming that settling takes place in two zones (a constant rate zone and a variable rate zone), a model using four parameters accounting for the nature of the water-suspension system has been proposed for describing batch sedimentation processes. The sludge volume index (SVI) has been expressed in terms of these parameters. Some disadvantages of the SVI application as a design parameter have been pointed out, and it has been shown that a relationship between zone settling velocity and sludge concentration is more consistent for describing the settling behavior and for design of settling tanks. The permissible overflow rate has been related to the technological parameters of secondary settling tank by simple working equations. The graphical representations of these equations could be used to optimize the design and operation of secondary settling tanks.

Persistence and partitioning of eight selected pharmaceuticals in the aquatic environment: laboratory photolysis, biodegradation, and sorption experiments.

PubMed

Yamamoto, Hiroshi; Nakamura, Yudai; Moriguchi, Shigemi; Nakamura, Yuki; Honda, Yuta; Tamura, Ikumi; Hirata, Yoshiko; Hayashi, Akihide; Sekizawa, Jun

2009-02-01

We selected eight pharmaceuticals with relatively high potential ecological risk and high consumption-namely, acetaminophen, atenolol, carbamazepine, ibuprofen, ifenprodil, indomethacin, mefenamic acid, and propranolol-and conducted laboratory experiments to examine the persistence and partitioning of these compounds in the aquatic environment. In the results of batch sunlight photolysis experiments, three out of eight pharmaceuticals-propranolol, indomethacin, and ifenprodil-were relatively easily photodegraded (i.e., half-life<24h), whereas the other five pharmaceuticals were relatively stable against sunlight. The results of batch biodegradation experiments using river water suggested relatively slow biodegradation (i.e., half-life>24h) for all eight pharmaceuticals, but the rate constant was dependent on sampling site and time. Batch sorption experiments were also conducted to determine the sorption coefficients to river sediments and a model soil sample. The determined coefficients (K(d) values) were much higher for three amines (atenolol, ifenprodil, and propranolol) than for neutral compounds or carboxylic acids; the K(d) values of the amines were comparable to those of a four-ring polycyclic aromatic hydrocarbon (PAH) pyrene. The coefficients were also higher for sediment/soil with higher organic content, and the organic carbon-based sorption coefficient (logK(oc)) showed a poor linear correlation with the octanol-water distribution coefficient (logD(ow)) at neutral pH. These results suggest other sorption mechanisms-such as electrochemical affinity, in addition to hydrophobic interaction-play an important role in sorption to sediment/soil at neutral pH.

Generalized mathematical model of red muds’ thickener of alumina production

NASA Astrophysics Data System (ADS)

Fedorova, E. R.; Vinogradova, A. A.

2018-03-01

The article describes the principle of a generalized mathematical model of the red mud’s thickener construction. The model of the red muds’ thickener of alumina production consists of sub-models of flocculation zones containing solid fraction feed slurry, free-fall and cramped sedimentation zones or effective sedimentation zones, bleaching zones. The generalized mathematical model of thickener allows predicting the content of solid fraction in the condensed product and in the upper discharge. The sub-model of solid phase aggregation allows one to count up average size of floccules, which is created during the flocculation process in feedwell. The sub-model of the free-fall and cramped sedimentation zone allows one to count up the concentration profile taking into account the variable cross-sectional area of the thickener. The sub-model of the bleaching zone is constructed on the basis of the theory of the precipitation of Kinc, supplemented by correction factors.

Reductive microbial dechlorination of indigenous polychlorinated biphenyls in soil using a sediment-free inoculum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klasson, K.T.; Barton, J.W.; Evans, B.S.

1996-05-01

In laboratory experiments, unagitated soil slurry bioreactors inoculated with microorganisms extracted from polychlorinated biphenyl-contaminated (PCBs) sediments from the Hudson River were used to anaerobically dechlorinate PCBs. The onset of dechlorination activity was accelerated by the addition of certain organic acids (pyruvate and maleate) and single congeners (2,3,6-trichlorobiphenyl). Dechlorination was observed under several working conditions after 19 weeks of incubation with PCB-contaminated soil and nutrient solution. Best results showed a drop in average chlorine content from 4.3 to 3.6 chlorines per biphenyl due to a loss of m-chlorines. Soil used for these experiments was obtained from a PCB-contaminated (weathered Aroclor 1248)more » site at an electric power substation. Dechlorination was observed with no sediment particles or other matrix being added. 17 refs., 6 figs., 1 tab.« less

SLUDGE BATCH 7B QUALIFICATION ACTIVITIES WITH SRS TANK FARM SLUDGE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pareizs, J.; Click, D.; Lambert, D.

2011-11-16

Waste Solidification Engineering (WSE) has requested that characterization and a radioactive demonstration of the next batch of sludge slurry - Sludge Batch 7b (SB7b) - be completed in the Shielded Cells Facility of the Savannah River National Laboratory (SRNL) via a Technical Task Request (TTR). This characterization and demonstration, or sludge batch qualification process, is required prior to transfer of the sludge from Tank 51 to the Defense Waste Processing Facility (DWPF) feed tank (Tank 40). The current WSE practice is to prepare sludge batches in Tank 51 by transferring sludge from other tanks. Discharges of nuclear materials from Hmore » Canyon are often added to Tank 51 during sludge batch preparation. The sludge is washed and transferred to Tank 40, the current DWPF feed tank. Prior to transfer of Tank 51 to Tank 40, SRNL typically simulates the Tank Farm and DWPF processes with a Tank 51 sample (referred to as the qualification sample). With the tight schedule constraints for SB7b and the potential need for caustic addition to allow for an acceptable glass processing window, the qualification for SB7b was approached differently than past batches. For SB7b, SRNL prepared a Tank 51 and a Tank 40 sample for qualification. SRNL did not receive the qualification sample from Tank 51 nor did it simulate all of the Tank Farm washing and decanting operations. Instead, SRNL prepared a Tank 51 SB7b sample from samples of Tank 7 and Tank 51, along with a wash solution to adjust the supernatant composition to the final SB7b Tank 51 Tank Farm projections. SRNL then prepared a sample to represent SB7b in Tank 40 by combining portions of the SRNL-prepared Tank 51 SB7b sample and a Tank 40 Sludge Batch 7a (SB7a) sample. The blended sample was 71% Tank 40 (SB7a) and 29% Tank 7/Tank 51 on an insoluble solids basis. This sample is referred to as the SB7b Qualification Sample. The blend represented the highest projected Tank 40 heel (as of May 25, 2011), and thus, the highest projected noble metals content for SB7b. Characterization was performed on the Tank 51 SB7b samples and SRNL performed DWPF simulations using the Tank 40 SB7b material. This report documents: (1) The preparation and characterization of the Tank 51 SB7b and Tank 40 SB7b samples. (2) The performance of a DWPF Chemical Process Cell (CPC) simulation using the SB7b Tank 40 sample. The simulation included a Sludge Receipt and Adjustment Tank (SRAT) cycle, where acid was added to the sludge to destroy nitrite and reduce mercury, and a Slurry Mix Evaporator (SME) cycle, where glass frit was added to the sludge in preparation for vitrification. The SME cycle also included replication of five canister decontamination additions and concentrations. Processing parameters were based on work with a nonradioactive simulant. (3) Vitrification of a portion of the SME product and characterization and durability testing (as measured by the Product Consistency Test (PCT)) of the resulting glass. (4) Rheology measurements of the SRAT receipt, SRAT product, and SME product. This program was controlled by a Task Technical and Quality Assurance Plan (TTQAP), and analyses were guided by an Analytical Study Plan. This work is Technical Baseline Research and Development (R&D) for the DWPF. It should be noted that much of the data in this document has been published in interoffice memoranda. The intent of this technical report is bring all of the SB7b related data together in a single permanent record and to discuss the overall aspects of SB7b processing.« less

Impacts of Activated Carbon Amendment on Hg Methylation, Demethylation and Microbial Activity in Marsh Soils

NASA Astrophysics Data System (ADS)

Gilmour, C. C.; Ghosh, U.; Santillan, E. F. U.; Soren, A.; Bell, J. T.; Butera, D.; McBurney, A. W.; Brown, S.; Henry, E.; Vlassopoulos, D.

2015-12-01

In-situ sorbent amendments are a low-impact approach for remediation of contaminants in sediments, particular in habitats like wetlands that provide important ecosystem services. Laboratory microcosm trials (Gilmour et al. 2013) and early field trials show that activated carbon (AC) can effectively increase partitioning of both inorganic Hg and methylmercury to the solid phase. Sediment-water partitioning can serve as a proxy for Hg and MeHg bioavailability in soils. One consideration in using AC in remediation is its potential impact on organisms. For mercury, a critical consideration is the potential impact on net MeHg accumulation and bioavailability. In this study, we specifically evaluated the impact of AC on rates of methylmercury production and degradation, and on overall microbial activity, in 4 different Hg-contaminated salt marsh soils. The study was done over 28 days in anaerobic, sulfate-reducing slurries. A double label of enriched mercury isotopes (Me199Hg and inorganic 201Hg) was used to separately follow de novo Me201Hg production and Me199Hg degradation. AC amendments decreased both methylation and demethylation rate constants relative to un-amended controls, but the impact on demethylation was stronger. The addition of 5% (dry weight) regenerated AC to soil slurries drove demethylation rate constants to nearly zero; i.e. MeHg sorption to AC almost totally blocked its degradation. The net impact was increased solid phase MeHg concentrations in some of the soil slurries with the highest methylation rate constants. However, the net impact of AC amendments was to increase MeHg (and inorganic Hg) partitioning to the soil phase and decrease concentrations in the aqueous phase. AC significantly decreased aqueous phase inorganic Hg and MeHg concentrations after 28 days. Overall, the efficacy of AC in reducing aqueous MeHg was highest in the soils with the highest MeHg concentrations. The AC addition did not significantly impact microbial activity, as assessed by CO2 production and sulfate depletion, in two of the four soils, but resulted in a up to a 40% decrease in two other soils. AC amendment has little effect on slurry pH, but decreased aqueous Fe, sulfide and DOC concentrations.

Seasonal variations in erodibility and sediment transport potential in a mesotidal channel-flat complex, Willapa Bay, WA

NASA Astrophysics Data System (ADS)

Wiberg, Patricia L.; Law, Brent A.; Wheatcroft, Robert A.; Milligan, Timothy G.; Hill, Paul S.

2013-06-01

Measurements of erodibility, porosity and sediment size were made three times over the course of a year at sites within a muddy, mesotidal flat-channel complex in southern Willapa Bay, WA, to examine spatial and seasonal variations in sediment properties and transport potential. Average critical shear stress profiles, the metric we used for erodibility, were quantified using a power-law fit to cumulative eroded mass vs. shear stress for the flats and channel. Laboratory erosion measurements of deposits made from slurries of flat and channel sediment were used to quantify erodibility over consolidation time scales ranging from 6 to 96h. Erodibility of the tidal flats was consistently low, with spatial variability comparable to seasonal variability despite seasonal changes in biological activity. In contrast, channel-bed erodibility underwent large seasonal variations, with mobile sediment present in the channel thalweg during winter that was absent in the spring and summer, when channel-bed erodibility was low and comparable to that of the tidal flats. Sediment on the northern (left) channel flank was mobile in summer and winter, whereas sediment on the southern flank was not. Seasonal changes in channel-bed erodibility are sufficient to produce order-of-magnitude changes in suspended sediment concentrations during peak tidal flows. Porosity just below the sediment surface was the best predictor of erodibility in our study area.

Organic Matter Loading Modifies the Microbial Community Responsible for Nitrogen Loss in Estuarine Sediments.

PubMed

Babbin, Andrew R; Jayakumar, Amal; Ward, Bess B

2016-04-01

Coastal marine sediments, as locations of substantial fixed nitrogen loss, are very important to the nitrogen budget and to the primary productivity of the oceans. Coastal sediment systems are also highly dynamic and subject to periodic natural and anthropogenic organic substrate additions. The response to organic matter by the microbial community involved in nitrogen loss processes was evaluated using mesocosms of Chesapeake Bay sediments. Over the course of a 50-day incubation, rates of anammox and denitrification were measured weekly using (15)N tracer incubations, and samples were collected for genetic analysis. Rates of both nitrogen loss processes and gene abundances associated with them corresponded loosely, probably because heterogeneities in sediments obscured a clear relationship. The rates of denitrification were stimulated more, and the fraction of nitrogen loss attributed to anammox slightly reduced, by the higher organic matter addition. Furthermore, the large organic matter pulse drove a significant and rapid shift in the denitrifier community composition as determined using a nirS microarray, indicating that the diversity of these organisms plays an essential role in responding to anthropogenic inputs. We also suggest that the proportion of nitrogen loss due to anammox in these coastal estuarine sediments may be underestimated due to temporal dynamics as well as from methodological artifacts related to conventional sediment slurry incubation approaches.

Enrichment and cultivation of prokaryotes associated with the sulphate-methane transition zone of diffusion-controlled sediments of Aarhus Bay, Denmark, under heterotrophic conditions.

PubMed

Webster, Gordon; Sass, Henrik; Cragg, Barry A; Gorra, Roberta; Knab, Nina J; Green, Christopher J; Mathes, Falko; Fry, John C; Weightman, Andrew J; Parkes, R John

2011-08-01

The prokaryotic activity, diversity and culturability of diffusion-controlled Aarhus Bay sediments, including the sulphate-methane transition zone (SMTZ), were determined using a combination of geochemical, molecular (16S rRNA and mcrA genes) and cultivation techniques. The SMTZ had elevated sulphate reduction and anaerobic oxidation of methane, and enhanced cell numbers, but no active methanogenesis. The prokaryotic population was similar to that in other SMTZs, with Deltaproteobacteria, Gammaproteobacteria, JS1, Planctomycetes, Chloroflexi, ANME-1, MBG-D and MCG. Many of these groups were maintained in a heterotrophic (10 mM glucose, acetate), sediment slurry with periodic low sulphate and acetate additions (~2 mM). Other prokaryotes were also enriched including methanogens, Firmicutes, Bacteroidetes, Synergistetes and TM6. This slurry was then inoculated into a matrix of substrate and sulphate concentrations for further selective enrichment. The results demonstrated that important SMTZ bacteria can be maintained in a long-term, anaerobic culture under specific conditions. For example, JS1 grew in a mixed culture with acetate or acetate/glucose plus sulphate. Chloroflexi occurred in a mixed culture, including in the presence of acetate, which had previously not been shown to be a Chloroflexi subphylum I substrate, and was more dominant in a medium with seawater salt concentrations. In contrast, archaeal diversity was reduced and limited to the orders Methanosarcinales and Methanomicrobiales. These results provide information about the physiology of a range of SMTZ prokaryotes and shows that many can be maintained and enriched under heterotrophic conditions, including those with few or no cultivated representatives. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Water quality impact assessment of agricultural Beneficial Management Practices (BMPs) simulated for a regional catchment in Quebec, Eastern Canada

NASA Astrophysics Data System (ADS)

Rousseau, Alain N.; Hallema, Dennis W.; Gumiere, Silvio J.; Savary, Stéphane; Hould Gosselin, Gabriel

2014-05-01

Water quality has become a matter of increasing concern over the past four decades as a result of the intensification of agriculture, and more particularly so in Canada where agriculture has evolved into the largest non-point source of surface water pollution. The Canadian WEBs project (Watershed Evaluation of Beneficial Management Practices, BMPs) was initiated in order to determine the efficiency of BMPs in improving the surface water quality of rural catchments, and the economic aspects related to their implementation on the same scale. In this contribution we use the integrated watershed modelling platform GIBSI (Gestion Intégrée des Bassins versants à l'aide d'un Système Informatisé) to evaluate the effects of various BMPs on sediment and nutrient yields and, in close relation to this, the surface water quality for the Beaurivage River catchment (718 km2) in Quebec, eastern Canada. A base scenario of the catchment is developed by calibrating the different models of the GIBSI platform, namely HYDROTEL for hydrology, the Revised Universal Soil Loss Equation (RUSLE) for soil erosion, the Erosion-Productivity Impact Calculator (EPIC) of the Soil and Water Assessment Tool (SWAT) for contaminant transport and fate, and QUAL2E for stream water quality. Four BMPs were analysed: (1) vegetated riparian buffer strips, (2) precision slurry application, (3) transition of all cereal and corn fields to grassland (grassland conversion), and (4) no-tillage on corn fields. Simulations suggest that riparian buffer strips and grassland conversion are more effective in terms of phosphorus, nitrogen and sediment load reduction than precision slurry application and no-tillage on corn fields. The results furthermore indicate the need for a more profound understanding of sediment dynamics in streams and on riparian buffer strips.

Reactive and recoverable sorbents for halogenated organic compound remediation in sediments

NASA Astrophysics Data System (ADS)

Werner, David; Taggalou, Villy; Kordulis, Christos; Dolfing, Jan; Karapanagioti, Hrissi K.

2013-04-01

Activated carbon (AC) has been proposed as a sediment amendment for aquatic systems polluted with hydrophobic organic compounds. AC acts as a strong binding agent that lowers the pollutant concentration and thus, its toxicity. A draw back of this in-situ remediation method is that although the pollutant will remain non-bioavailable for many years being sorbed into AC, it actually stays in the system. A reactive sorbent, a sorbent that would, at the same time, facilitate the degradation of the pollutant, would be better accepted by the public or the regulators than AC amendment. So far, catalysts supported on AC with zero valent iron and a reactive metal have been proposed for the dechlorination of chlorinated organic compounds. These reactive metals are usually expensive or toxic and thus, their addition to the environment is not desirable. In the present study, activated carbon modified with reduced iron(AC/Fe) is tested in batch systems in the presence of sediment and DDT sorbed on polyethylene sheets. The batch systems are equilibrated for different contact times. Then, the DDT remaining in the polyethylene sheets is quantified along with DDD produced due to the dechlorination of DDT. A small percentage of DDT is degraded to DDD in the systems containing the AC/Fe material. No degradation of DDT is observed in the control systems containing the pollutant and the sediment or the pollutant, the sediment and AC. Thus, the addition of AC/Fe to the sediment with the DDT is enough to cause the dechlorination of DDT. At the end of the experiments, a magnet rod is used to recover the AC/Fe material from the batches with the sediment. An average recovery of 83% is achieved. This is a high percentage suggesting that the material can be easily recovered. Some drawbacks of the material preparation method are identified after the composite material characterization. For example, the AC/Fe surface area is decreased with the material preparation compared to the initial surface area of the AC. This fact results in decrease of the sorption ability of the AC/Fe material compared to that of the AC. At the same time, more DDT degradation might be achievable by increasing the AC/Fe dosage from the 1% weight used in this study that is lower than commonly used for sediment amendments. More research is necessary to optimize the material preparation and properties.

Coupled Geochemical Impacts of Leaking CO2 and Contaminants from Subsurface Storage Reservoirs on Groundwater Quality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao, Hongbo; Qafoku, Nikolla; Lawter, Amanda R.

2015-07-07

The leakage of CO2 and the concomitant saline solutions from deep storage reservoirs to overlying groundwater aquifers is considered one of the major potential risks associated with geologic CO2 sequestration (GCS). Batch and column experiments were conducted to determine the fate of trace metals in groundwater in the scenarios of CO2 and metal contaminated brine leakage. The sediments used in this work were collected from an unconsolidated sand and gravel aquifer in Kansas, and contained 0-4 wt% carbonates. Cd and As were spiked into the reaction system to represent potential contaminants from the reservoir brine that could intrude into groundwatermore » aquifers with leaking CO2 at initial concentrations of 114 and 40 ppb, respectively. Through this research we demonstrated that Cd and As were adsorbed on the sediments, in spite of the lowered pH due to CO2 dissolution in the groundwater. Cd concentrations were well below its MCL in both batch and column studies, even for sediment samples without detectable carbonate to buffer the pH. Arsenic concentrations in the effluent were also significantly lower than influent concentration, suggesting that the sediments tested have the capacity to mitigate the coupled adverse effects of CO2 leakage and brine intrusion. However, the mitigation capacity of sediment is a function of its geochemical properties [e.g., the calcite content; the presence of adsorbed As(III); and the presence of P in the natural sediment]. The competitive adsorption between phosphate and arsenate may result in higher concentrations of As in the aqueous phase.« less

An experimental and modeling study of grain-scale uranium desorption from field-contaminated sediments and the potential influence of microporosity on mass-transfer

NASA Astrophysics Data System (ADS)

Stoliker, D.; Liu, C.; Kent, D. B.; Zachara, J. M.

2012-12-01

The aquifer below the 300-Area of the Hanford site (Richland, WA, USA) is plagued by a persistent plume of dissolved uranium (U(VI)) in excess of the Environmental Protection Agency drinking water maximum contamination level even after the removal of highly contaminated sediments. The aquifer sediments in the seasonally saturated lower vadose zone act as both a source and sink for uranium during stage changes in the nearby Columbia River. Diffusion limitation of uranium mass-transfer within these sediments has been cited as a potential cause of the plume's persistence. Equilibrium U(VI) sorption is a strong function of variable chemical conditions, especially carbonate, hydrogen, and uranyl ion activities. Field-contaminated sediments from the site require up to 1,000 hours to reach equilibrium in static batch reactors. Increases in U(VI) concentrations over longer time-scales result from changes in chemical conditions, which drive reactions with sediments that favor U(VI) desorption. Grain-scale U(VI) sorption/desorption rates are slow, likely owing to diffusion of U(VI) and other solutes through intra-granular pore domains. In order to improve understanding of the impact of intra-granular diffusion and chemical reactions controlling grain-scale U(VI) release, experiments were conducted on individual particle size fractions of a <8 mm composite of field-contaminated, lower vadose zone sediments. For each size fraction, equilibrium U(VI) sorption/desorption in static batch reactors was well-described by surface complexation models over a range of chemical conditions applicable to the field site. Desorption rates from individual size fractions in flow-through batch reactors, examined under a single set of constant chemical conditions with multiple stop-flow events, were similar for all size fractions <2 mm. Kinetic U(VI) desorption in flow-through batch reactors was modeled using a multi-rate surface complexation approach, where sorption/desorption rates were assumed to be proportional to the displacement from equilibrium and multiple diffusion domains were described with a two-parameter lognormal distribution of mass-transfer rate coefficients. Parameters describing mass transfer were the same for all size fractions <2 mm but differed for the largest (2-8 mm) size fraction. The evolution of pH, along with dissolved cation and carbonate concentrations, was modeled using equilibrium cation exchange, rate-limited calcite dissolution, aerobic respiration, and silica dissolution. Desorption and chemical reaction models calibrated with individual size fractions predicted U(VI) and chemical composition as a function of time for the bulk sediment sample. Volumes of pores less than 2.4 nm, quantified using nitrogen adsorption-desorption isotherms, were the same for all size fractions < 2 mm, nearly double that of the 2-8 mm size fraction. Similarity in the observed pore volumes and multi-rate mass-transfer parameters across all size fractions <2 mm suggest the importance of pores in this size class in controlling slow grain-scale U(VI) desorption rates. Models like these provide a means for testing the influence of grain-scale mass-transfer on the persistence of U(VI) plume at the site.

Pyrethroid sorption to Sacramento River suspended solids and bed sediments

PubMed Central

Fojut, Tessa L.; Young, Thomas M.

2011-01-01

Sorption of pyrethroid insecticides to solid materials will typically dominate the fate and transport of these hydrophobic compounds in aquatic environments. Batch reactor isotherm experiments were performed with bifenthrin and λ-cyhalothrin with suspended material and bed sediment collected from the Sacramento River, CA. These batch reactor experiments were performed with low spiking concentrations and a long equilibration time (28 d) to be more relevant to environmental conditions. Sorption to suspended material and bed sediment was compared to examine the role of differential sorption between these phases in the environmental transport of pyrethroids. The equilibrium sorption data were fit to the Freundlich isotherm model and fit with r2 > 0.87 for all experiments. Freundlich exponents ranged from 0.72 ± 0.19 to 1.07 ± 0.050, indicating sorption nonlinearity for some of the experimental conditions and linearity for others over the concentration range tested. The Freundlich capacity factors were larger for the suspended solids than for the bed sediments and the suspended material had a higher specific surface area and higher organic carbon content compared to the bed sediment. Calculated organic carbon-normalized distribution coefficients were larger than those previously reported in the literature by approximately an order of magnitude and ranged from 106.16 to 106.68 at an equilibrium aqueous concentration of 0.1 µg/L. Higher than expected sorption of pyrethroids to the tested materials may be explained by sorption to black carbon and/or mineral surfaces. PMID:21191877

MST Filterability Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poirier, M. R.; Burket, P. R.; Duignan, M. R.

2015-03-12

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). The low filter flux through the ARP has limited the rate at which radioactive liquid waste can be treated. Recent filter flux has averaged approximately 5 gallons per minute (gpm). Salt Batch 6 has had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. In addition, at the time the testing started, SRRmore » was assessing the impact of replacing the 0.1 micron filter with a 0.5 micron filter. This report describes testing of MST filterability to investigate the impact of filter pore size and MST particle size on filter flux and testing of filter enhancers to attempt to increase filter flux. The authors constructed a laboratory-scale crossflow filter apparatus with two crossflow filters operating in parallel. One filter was a 0.1 micron Mott sintered SS filter and the other was a 0.5 micron Mott sintered SS filter. The authors also constructed a dead-end filtration apparatus to conduct screening tests with potential filter aids and body feeds, referred to as filter enhancers. The original baseline for ARP was 5.6 M sodium salt solution with a free hydroxide concentration of approximately 1.7 M.3 ARP has been operating with a sodium concentration of approximately 6.4 M and a free hydroxide concentration of approximately 2.5 M. SRNL conducted tests varying the concentration of sodium and free hydroxide to determine whether those changes had a significant effect on filter flux. The feed slurries for the MST filterability tests were composed of simple salts (NaOH, NaNO 2, and NaNO 3) and MST (0.2 – 4.8 g/L). The feed slurry for the filter enhancer tests contained simulated salt batch 6 supernate, MST, and filter enhancers.« less

Effect of excess pore pressure on the long runout of debris flows over low gradient channels: A case study of the Dongyuege debris flow in Nu River, China

NASA Astrophysics Data System (ADS)

Zhou, Zhen-Hua; Ren, Zhe; Wang, Kun; Yang, Kui; Tang, Yong-Jun; Tian, Lin; Xu, Ze-Min

2018-05-01

Debris flows with long reaches are one of the major natural hazards to human life and property on alluvial fans, as shown by the debris flow that occurred in the Dongyuege (DYG) Gully in August 18, 2010, and caused 96 deaths. The travel distance and the runout distance of the DYG large-scale tragic debris flow were 11 km and 9 km, respectively. In particular, the runout distance over the low gradient channel (channel slope < 5°) upstream of the depositional fan apex reached up to 3.3 km. The build-up and maintenance of excess pore pressure in the debris-flow mass might have played a crucial role in the persistence and long runout of the bouldery viscous debris flow. Experiments to measure pore pressure and pore water escape have been carried out by reconstituting the debris flow bodies with the DYG debris flow deposit. The slurrying of the debris is governed by solid volumetric concentration (SVC), and the difference between the lower SVC limit and the upper SVC limit can be defined as debris flow index (Id). Peak value (Kp) and rate of dissipation (R) of relative excess pore pressure are dependent on SVC. Further, the SVC that gives the lowest rate of dissipation is regarded as the optimum SVC (Cvo). The dissipation response of excess pore pressure can be characterized by the R value under Cvo at a given moment (i.e., 0.5 h, 1 h or 2 h later after peak time). The results reveal that a relatively high level of excess pore pressure developed within the DYG debris-flow mass and had a strong persistence capability. Further research shows that the development, peak value and dissipation of excess pore pressure in a mixture of sediment and water are related to the maximum grain size (MGS), gradation and mineralogy of clay-size particles of the sediment. The layer-lattice silicates in clay particles can be the typical clay minerals, including kaolinite, montmorillonite and illite, and also the unrepresentative clay minerals such as muscovite and chlorite. Moreover, small woody debris can also contribute to the slurrying of sediments and maintenance of debris flows in well vegetated mountainous areas and the boulders suspended in debris flows can elevate excess pore pressure and extend debris-flow mobility. The parameters, including Id, Kp, R and etc., are affected by the intrinsic properties of debris. They, therefore, can reflect the slurrying susceptibility of sediments, and can also be applied to the research on the occurrence mechanisms and risk assessment of other debris flows.

Effect of bioaugmentation by cellulolytic bacteria enriched from sheep rumen on methane production from wheat straw.

PubMed

Ozbayram, E Gozde; Kleinsteuber, Sabine; Nikolausz, Marcell; Ince, Bahar; Ince, Orhan

2017-08-01

The aim of this study was to determine the potential of bioaugmentation with cellulolytic rumen microbiota to enhance the anaerobic digestion of lignocellulosic feedstock. An anaerobic cellulolytic culture was enriched from sheep rumen fluid using wheat straw as substrate under mesophilic conditions. To investigate the effects of bioaugmentation on methane production from straw, the enrichment culture was added to batch reactors in proportions of 2% (Set-1) and 4% (Set-2) of the microbial cell number of the standard inoculum slurry. The methane production in the bioaugmented reactors was higher than in the control reactors. After 30 days of batch incubation, the average methane yield was 154 mL N CH 4 g VS -1 in the control reactors. Addition of 2% enrichment culture did not enhance methane production, whereas in Set-2 the methane yield was increased by 27%. The bacterial communities were examined by 454 amplicon sequencing of 16S rRNA genes, while terminal restriction fragment length polymorphism (T-RFLP) fingerprinting of mcrA genes was applied to analyze the methanogenic communities. The results highlighted that relative abundances of Ruminococcaceae and Lachnospiraceae increased during the enrichment. However, Cloacamonaceae, which were abundant in the standard inoculum, dominated the bacterial communities of all batch reactors. T-RFLP profiles revealed that Methanobacteriales were predominant in the rumen fluid, whereas the enrichment culture was dominated by Methanosarcinales. In the batch rectors, the most abundant methanogens were affiliated to Methanobacteriales and Methanomicrobiales. Our results suggest that bioaugmentation with sheep rumen enrichment cultures can enhance the performance of digesters treating lignocellulosic feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.

Geochemical heterogeneity in a sand and gravel aquifer: Effect of sediment mineralogy and particle size on the sorption of chlorobenzenes

USGS Publications Warehouse

Barber, L.B.; Thurman, E.M.; Runnells, D.R.; ,

1992-01-01

The effect of particle size, mineralogy and sediment organic carbon (SOC) on solution of tetrachlorobenzene and pentachlorobenzene was evaluated using batch-isotherm experiments on sediment particle-size and mineralogical fractions from a sand and gravel aquifer, Cape Cod, Massachusetts. Concentration of SOC and sorption of chlorobenzenes increase with decreasing particle size. For a given particle size, the magnetic fraction has a higher SOC content and sorption capacity than the bulk or non-magnetic fractions. Sorption appears to be controlled by the magnetic minerals, which comprise only 5-25% of the bulk sediment. Although SOC content of the bulk sediment is < 0.1%, the observed sorption of chlorobenzenes is consistent with a partition mechanism and is adequately predicted by models relating sorption to the octanol/water partition coefficient of the solute and SOC content. A conceptual model based on preferential association of dissolved organic matter with positively-charged mineral surfaces is proposed to describe micro-scale, intergranular variability in sorption properties of the aquifer sediments.The effect of particle size, mineralogy and sediment organic carbon (SOC) on sorption of tetrachlorobenzene and pentachlorobenzene was evaluated using batch-isotherm experiments on sediment particle-size and mineralogical fractions from a sand and gravel aquifer, Cape Cod, Massachusetts. Concentration of SOC and sorption of chlorobenzenes increase with decreasing particle size. For a given particle size, the magnetic fraction has a higher SOC content and sorption capacity than the bulk or non-magnetic fractions. Sorption appears to be controlled by the magnetic minerals, which comprise only 5-25% of the bulk sediment. Although SOC content of the bulk sediment is <0.1%, the observed sorption of chlorobenzenes is consistent with a partition mechanism and is adequately predicted by models relating sorption to the octanol/water partition coefficient of the solute and SOC content. A conceptual model based on preferential association of dissolved organic matter with positively-charged mineral surfaces is proposed to describe micro-scale, intergranular variability in sorption properties of the aquifer sediments.

Improving Polycyclic Aromatic Hydrocarbon Biodegradation in Contaminated Soil Through Low-Level Surfactant Addition After Conventional Bioremediation

PubMed Central

Adrion, Alden C.; Singleton, David R.; Nakamura, Jun; Shea, Damian; Aitken, Michael D.

2016-01-01

Abstract Efficacy of bioremediation for soil contaminated with polycyclic aromatic hydrocarbons (PAHs) may be limited by the fractions of soil-bound PAHs that are less accessible to PAH-degrading microorganisms. In previous test-tube-scale work, submicellar doses of nonionic surfactants were screened for their ability to enhance the desorption and biodegradation of residual PAHs in soil after conventional bioremediation in a laboratory-scale, slurry-phase bioreactor. Polyoxyethylene sorbitol hexaoleate (POESH) was the optimum surfactant for enhancing PAH removal, especially the high–molecular weight PAHs. This work extends that concept by treating the effluent from the slurry-phase bioreactor in a second-stage batch reactor, to which POESH was added, for an additional 7 or 12 days. Surfactant amendment removed substantial amounts of the PAHs and oxy-PAHs remaining after conventional slurry-phase bioremediation, including more than 80% of residual 4-ring PAHs. Surfactant-amended treatment decreased soil cytotoxicity, but often increased the genotoxicity of the soil as measured using the DT-40 chicken lymphocyte DNA damage response assay. Potential ecotoxicity, measured using a seed germination assay, was reduced by bioreactor treatment and was reduced further after second-stage treatment with POESH. Of bacteria previously implicated as potential PAH degraders under POESH-amended conditions in a prior study, members of the Terrimonas genus were associated with differences in high–molecular weight PAH removal in the current study. Research using submicellar doses of surfactant as a second-stage treatment step is limited and these findings can inform the design of bioremediation systems at field sites treating soil contaminated with PAHs and other hydrophobic contaminants that have low bioaccessibility. PMID:27678476

Effect of aeration rate and waste load on evolution of volatile fatty acids and waste stabilization during thermophilic aerobic digestion of a model high strength agricultural waste.

PubMed

Ugwuanyi, J Obeta; Harvey, L M; McNeil, B

2005-04-01

Thermophilic aerobic digestion (TAD) is a relatively new, dynamic and versatile low technology for the economic processing of high strength waste slurries. Waste so treated may be safely disposed of or reused. In this work a model high strength agricultural waste, potato peel, was subjected to TAD to study the effects of oxygen supply at 0.1, 0.25, 0.5 and 1.0 vvm (volume air per volume slurry per minute) under batch conditions at 55 degrees C for 156 h on the process. Process pH was controlled at 7.0 or left unregulated. Effects of waste load, as soluble chemical oxygen demand (COD), on TAD were studied at 4.0, 8.0, 12.0 and 16.0 gl(-1) (soluble COD) at pH 7.0, 0.5 vvm and 55 degrees C. Efficiency of treatment, as degradation of total solids, total suspended solids and soluble solid, as well as soluble COD significantly increased with aeration rate, while acetate production increased as the aeration rate decreased or waste load increased, signifying deterioration in treatment. Negligible acetate, and no other acids were produced at 1.0 vvm. Production of propionate and other acids increased after acetate concentration had started to decrease and, during unregulated reactions coincided with the drop in the pH of the slurry. Acetate production was more closely associated with periods of oxygen limitation than were other acids. Reduction in oxygen availability led to deterioration in treatment efficiency as did increase in waste load. These variables may be manipulated to control treated waste quality.

Improving Polycyclic Aromatic Hydrocarbon Biodegradation in Contaminated Soil Through Low-Level Surfactant Addition After Conventional Bioremediation.

PubMed

Adrion, Alden C; Singleton, David R; Nakamura, Jun; Shea, Damian; Aitken, Michael D

2016-09-01

Efficacy of bioremediation for soil contaminated with polycyclic aromatic hydrocarbons (PAHs) may be limited by the fractions of soil-bound PAHs that are less accessible to PAH-degrading microorganisms. In previous test-tube-scale work, submicellar doses of nonionic surfactants were screened for their ability to enhance the desorption and biodegradation of residual PAHs in soil after conventional bioremediation in a laboratory-scale, slurry-phase bioreactor. Polyoxyethylene sorbitol hexaoleate (POESH) was the optimum surfactant for enhancing PAH removal, especially the high-molecular weight PAHs. This work extends that concept by treating the effluent from the slurry-phase bioreactor in a second-stage batch reactor, to which POESH was added, for an additional 7 or 12 days. Surfactant amendment removed substantial amounts of the PAHs and oxy-PAHs remaining after conventional slurry-phase bioremediation, including more than 80% of residual 4-ring PAHs. Surfactant-amended treatment decreased soil cytotoxicity, but often increased the genotoxicity of the soil as measured using the DT-40 chicken lymphocyte DNA damage response assay. Potential ecotoxicity, measured using a seed germination assay, was reduced by bioreactor treatment and was reduced further after second-stage treatment with POESH. Of bacteria previously implicated as potential PAH degraders under POESH-amended conditions in a prior study, members of the Terrimonas genus were associated with differences in high-molecular weight PAH removal in the current study. Research using submicellar doses of surfactant as a second-stage treatment step is limited and these findings can inform the design of bioremediation systems at field sites treating soil contaminated with PAHs and other hydrophobic contaminants that have low bioaccessibility.

Evaluation of the biomethane potential from multiple waste streams for a proposed community scale anaerobic digester.

PubMed

Browne, James D; Allen, Eoin; Murphy, Jerry D

2013-01-01

This paper examines the biomethane potential from organic waste for a proposed community scale anaerobic digester in a rural town. The biomethane potential test is used to assess the suitability of waste streams for biomethane production and to examine the variation in biomethane potential between waste sub-streams. A methodology for accurately estimating the biomethane potential from multiple heterogeneous organic waste substrates is sought. Five main waste streams were identified as possible substrates for biogas production, namely Abattoir waste (consisting of paunch and de-watered activated sludge); cheese factory effluent; commercial and domestic food waste; pig slurry and waste water treatment sludge. The biomethane potential of these waste streams ranged from as low as 99 L CH4 kg VS(-1) for pig slurry to as high as 787 L CH4 kg VS(-1) for dissolved air floatation (DAF) sludge from a cheese effluent treatment plant. The kinetic behaviour of the biomethane production in the batch test is also examined. The objective of the paper is to suggest an optimum substrate mix in terms of biomethane yield per unit substrate for the proposed anaerobic digester. This should maximize the yield of biomethane per capital investment. Food waste displayed the highest biomethane yield (128 m(n)(3) t(-1)) followed by cheese waste (38 m(n)(3) t(-1)) and abattoir waste (36 m(n)(3) t(-1)). It was suggested that waste water sludge (16 m(n)(3) t(-1)) and pig slurry (4 m(n)(3) t(-1)) should not be digested. However, the biomethane potential test does not give information on the continuous operation of an anaerobic digester.

Effects of dissolved CO2 on Shallow Freshwater Microbial Communities simulating a CO2 Leakage Scenario

NASA Astrophysics Data System (ADS)

Gulliver, D. M.; Lowry, G. V.; Gregory, K.

2013-12-01

Geological carbon sequestration is likely to be part of a comprehensive strategy to minimize the atmospheric release of greenhouse gasses, establishing a concern of sequestered CO2 leakage into overlying potable aquifers. Leaking CO2 may affect existing biogeochemical processes and therefore water quality. There is a critical need to understand the evolution of CO2 exposed microbial communities that influence the biogeochemistry in these freshwater aquifers. The evolution of microbial ecology for different CO2 exposure concentrations was investigated using fluid-slurry samples obtained from a shallow freshwater aquifer (55 m depth, 0.5 MPa, 22 °C, Escatawpa, MS). The microbial community of well samples upstream and downstream of CO2 injection was characterized. In addition, batch vessel experiments were conducted with the upstream aquifer samples exposed to varying pCO2 from 0% to 100% under reservoir temperature and pressure for up to 56 days. The microbial community of the in situ experiment and the batch reactor experiment were analyzed with 16S rRNA clone libraries and qPCR. In both the in situ experiment and the batch reactor experiment, DNA concentration did not correlate with CO2 exposure. Both the in situ experiment and the batch reactors displayed a changing microbial community with increased CO2 exposure. The well water isolate, Curvibacter, appeared to be the most tolerant genus to high CO2 concentrations in the in situ experiments and to mid-CO2 concentrations in the batch reactors. In batch reactors with pCO2 concentrations higher than experienced in situ (pCO2 = 0.5 MPa), Pseudomonas appeared to be the most tolerant genus. Findings provide insight into a dynamic biogeochemical system that will alter with CO2 exposure. Adapted microbial populations will eventually give rise to the community that will impact the metal mobility and water quality. Knowledge of the surviving microbial populations will enable improved models for predicting the fate of CO2 following leakage and lead to better strategies for ensuring the quality of potable aquifer water.

Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s.

PubMed

Miller, Laurence G; Baesman, Shaun M; Oremland, Ronald S

2015-11-01

We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2 compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus. Acetylene-Fermentation-Isotope fractionation-Enceladus-Life detection.

Investigations into the differential reactivity of endogenous and exogenous mercury species in coastal sediments.

PubMed

Bouchet, S; Rodriguez-Gonzalez, P; Bridou, R; Monperrus, M; Tessier, E; Anschutz, P; Guyoneaud, R; Amouroux, D

2013-03-01

Stable isotopic tracer methodologies now allow the evaluation of the reactivity of the endogenous (ambient) and exogenous (added) Hg to further predict the potential effect of Hg inputs in ecosystems. The differential reactivity of endogenous and exogenous Hg was compared in superficial sediments collected in a coastal lagoon (Arcachon Bay) and in an estuary (Adour River) from the Bay of Biscay (SW France). All Hg species (gaseous, aqueous, and solid fraction) and ancillary data were measured during time course slurry experiments under variable redox conditions. The average endogenous methylation yield was higher in the estuarine (1.2 %) than in the lagoonal sediment (0.5 %), although both methylation and demethylation rates were higher in the lagoonal sediment in relation with a higher sulfate-reducing activity. Demethylation was overall more consistent than methylation in both sediments. The endogenous and exogenous Hg behaviors were always correlated but the exogenous inorganic Hg (IHg) partitioning into water was 2.0-4.3 times higher than the endogenous one. Its methylation was just slightly higher (1.4) in the estuarine sediment while the difference in the lagoonal sediment was much larger (3.6). The relative endogenous and exogenous methylation yields were not correlated to IHg partitioning, demonstrating that the bioavailable species distributions were different for the two IHg pools. In both sediments, the exogenous IHg partitioning equaled the endogenous one within a week, while its higher methylation lasted for months. Such results provide an original assessment approach to compare coastal sediment response to Hg inputs.

Use of Sodium Dithionite as Part of a More Efficient Groundwater Restoration Method Following In-situ Recovery of Uranium at the Smith-Ranch Highland Site in Wyoming

NASA Astrophysics Data System (ADS)

Harris, R.; Reimus, P. W.; Ware, D.; Williams, K.; Chu, D.; Perkins, G.; Migdissov, A. A.; Bonwell, C.

2017-12-01

Uranium is primarily mined for nuclear power production using an aqueous extraction technique called in-situ recovery (ISR). ISR can pollute groundwater with residual uranium and other heavy metals. Reverse osmosis and groundwater sweep are currently used to restore groundwater after ISR mining, but are not permanent solutions. Sodium dithionite is being tested as part of a method to more permanently restore groundwater after ISR mining at the Smith-Ranch Highland site in Wyoming. Sodium dithionite is a chemical reductant that can reduce sediments that were oxidized during ISR. The reduced sediments can reduce soluble uranium (VI) in the groundwater to insoluble uranium (IV). Laboratory studies that use sodium dithionite to treat sediments and waters from the site may help predict how it will behave during a field deployment. An aqueous batch experiment showed that sodium dithionite reduced uranium in post-mined untreated groundwater from 38 ppm to less than 1 ppm after 1 day. A sediment reduction batch experiment showed that sodium dithionite-treated sediments were capable of reducing uranium in post-mined untreated groundwater from 38 ppm to 2 ppm after 7 days. One column experiment is showing post-mined sodium dithionite-treated sediments are capable of reducing uranium in post-mined groundwater for over 30 pore volumes past the initial injection. While these results are promising for field deployments of sodium dithionite, another column experiment with sodium dithionite-treated sediments containing uranium rich organic matter is showing net production of uranium instead of uranium uptake. Sodium dithionite appears to liberate uranium from the organic matter. Another sediment reduction experiment is being conducted to further investigate this hypothesis. These experiments are helping guide plans for field deployments of sodium dithionite at uranium ISR mining sites.

Final Scientific/Technical Report, DE-FG02-06ER64171, Integrated Nucleic Acid System for In-Field Monitoring of Microbial Community Dynamics and Metabolic Activity – Subproject to Co-PI Eric E. Roden

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eric E. Roden

2009-07-08

This report summarizes research conducted in conjunction with a project entitled “Integrated Nucleic Acid System for In-Field Monitoring of Microbial Community Dynamics and Metabolic Activity”, which was funded through the Integrative Studies Element of the former NABIR Program (now the Environmental Remediation Sciences Program) within the Office of Biological and Environmental Research. Dr. Darrell Chandler (originally at Argonne National Laboratory, now with Akonni Biosystems) was the overall PI/PD for the project. The overall project goals were to (1) apply a model iron-reducer and sulfate-reducer microarray and instrumentation systems to sediment and groundwater samples from the Scheibe et al. FRC Areamore » 2 field site, UMTRA sediments, and other DOE contaminated sites; (2) continue development and expansion of a 16S rRNA/rDNA¬-targeted probe suite for microbial community dynamics as new sequences are obtained from DOE-relevant sites; and (3) address the fundamental molecular biology and analytical chemistry associated with the extraction, purification and analysis of functional genes and mRNA in environmental samples. Work on the UW subproject focused on conducting detailed batch and semicontinuous culture reactor experiments with uranium-contaminated FRC Area 2 sediment. The reactor experiments were designed to provide coherent geochemical and microbiological data in support of microarray analyses of microbial communities in Area 2 sediments undergoing biostimulation with ethanol. A total of four major experiments were conducted (one batch and three semicontinuous culture), three of which (the batch and two semicontinuous culture) provided samples for DNA microarray analysis. A variety of other molecular analyses (clone libraries, 16S PhyloChip, RT-PCR, and T-RFLP) were conducted on parallel samples from the various experiments in order to provide independent information on microbial community response to biostimulation.« less

Extraction and concentration of phenolic compounds from water and sediment

USGS Publications Warehouse

Goldberg, Marvin C.; Weiner, Eugene R.

1980-01-01

Continuous liquid-liquid extractors are used to concentrate phenols at the ??g l-1 level from water into dichloromethane; this is followed by Kuderna-Danish evaporative concentration and gas chromatography. The procedure requires 5 h for 18 l of sample water. Overall concentration factors around 1000 are obtained. Overall concentration efficiencies vary from 23.1 to 87.1%. Concentration efficiencies determined by a batch method suitable for sediments range from 18.9 to 73.8%. ?? 1980.

Fertilizers mobilization in alluvial aquifer: laboratory experiments

NASA Astrophysics Data System (ADS)

Mastrocicco, M.; Colombani, N.; Palpacelli, S.

2009-02-01

In alluvial plains, intensive farming with conspicuous use of agrochemicals, can cause land pollution and groundwater contamination. In central Po River plain, paleo-channels are important links between arable lands and the underlaying aquifer, since the latter is often confined by clay sediments that act as a barrier against contaminants migration. Therefore, paleo-channels are recharge zones of particular interest that have to be protected from pollution as they are commonly used for water supply. This paper focuses on fertilizer mobilization next to a sand pit excavated in a paleo-channel near Ferrara (Italy). The problem is approached via batch test leaking and columns elution of alluvial sediments. Results from batch experiments showed fast increase in all major cations and anions, suggesting equilibrium control of dissolution reactions, limited availability of solid phases and geochemical homogeneity of samples. In column experiments, early elution and tailing of all ions breakthrough was recorded due to preferential flow paths. For sediments investigated in this study, dispersion, dilution and chemical reactions can reduce fertilizers at concentration below drinking standards in a reasonable time frame, provided fertilizer loading is halted or, at least, reduced. Thus, the definition of a corridor along paleo-channels is recommended to preserve groundwater quality.

Laboratory studies to characterize the efficacy of sand capping a coal tar-contaminated sediment.

PubMed

Hyun, Seunghun; Jafvert, Chad T; Lee, Linda S; Rao, P Suresh C

2006-06-01

Placement of a microbial active sand cap on a coal tar-contaminated river sediment has been suggested as a cost effective remediation strategy. This approach assumes that the flux of contaminants from the sediment is sufficiently balanced by oxygen and nutrient fluxes into the sand layer such that microbial activity will reduce contaminant concentrations within the new benthic zone and reduce the contaminant flux to the water column. The dynamics of such a system were evaluated using batch and column studies with microbial communities from tar-contaminated sediment under different aeration and nutrient inputs. In a 30-d batch degradation study on aqueous extracts of coal tar sediment, oxygen and nutrient concentrations were found to be key parameters controlling the degradation rates of polycyclic aromatic hydrocarbons (PAHs). For the five PAHs monitored (naphthalene, fluorene, phenanthrene, anthracene, and pyrene), degradation rates were inversely proportional to molecular size. For the column studies, where three columns were packed with a 20-cm sand layer on the top of a 5 cm of sediment layer, flow was established to sand layers with (1) aerated water, (2) N(2) sparged water, or (3) HgCl(2)-sterilized N(2) sparged water. After steady-state conditions, PAH concentrations in effluents were the lowest in the aerated column, except for pyrene, whose concentration was invariant with all effluents. These laboratory scale studies support that if sufficient aeration can be achieved in the field through either active and passive means, the resulting microbially active sand layer can improve the water quality of the benthic zone and reduce the flux of many, but not all, PAHs to the water column.

Process Development for Hydrothermal Liquefaction of Algae Feedstocks in a Continuous-Flow Reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Douglas C.; Hart, Todd R.; Schmidt, Andrew J.

Wet algae slurries can be converted into an upgradeable biocrude by hydrothermal liquefaction (HTL). High levels of carbon conversion to gravity-separable biocrude product were accomplished at relatively low temperature (350 °C) in a continuous-flow, pressurized (sub-critical liquid water) environment (20 MPa). As opposed to earlier work in batch reactors reported by others, direct oil recovery was achieved without the use of a solvent and biomass trace components were removed by processing steps so that they did not cause process difficulties. High conversions were obtained even with high slurry concentrations of up to 35 wt% of dry solids. Catalytic hydrotreating wasmore » effectively applied for hydrodeoxygenation, hydrodenitrogenation, and hydrodesulfurization of the biocrude to form liquid hydrocarbon fuel. Catalytic hydrothermal gasification was effectively applied for HTL byproduct water cleanup and fuel gas production from water soluble organics, allowing the water to be considered for recycle of nutrients to the algae growth ponds. As a result, high conversion of algae to liquid hydrocarbon and gas products was found with low levels of organic contamination in the byproduct water. All three process steps were accomplished in bench-scale, continuous-flow reactor systems such that design data for process scale-up was generated.« less

Effect of Free Ammonia, Free Nitrous Acid, and Alkalinity on the Partial Nitrification of Pretreated Pig Slurry, Using an Alternating Oxic/Anoxic SBR

PubMed Central

Hsieh, Chia-Fang; Guerrero, Lorna; Méndez, Ramón; Mosquera-Corral, Anuska; Vidal, Gladys

2017-01-01

The effect of free ammonia (NH3 or FA), free nitrous acid (HNO2 or FNA), and total alkalinity (TA) on the performance of a partial nitrification (PN) sequencing batch reactor (SBR) treating anaerobically pretreated pig slurry was studied. The SBR was operated under alternating oxic/anoxic (O/A) conditions and was fed during anoxic phases. This strategy allowed using organic matter to partially remove nitrite (NO2−) and nitrate (NO3−) generated during oxic phases. The desired NH4+ to NO2− ratio of 1.3 g N/g N was obtained when an Ammonium Loading Rate (ALR) of 0.09 g NH4+-N/L·d was applied. The system was operated at a solid retention time (SRT) of 15–20 d and dissolved oxygen (DO) levels higher than 3 mg O2/L during the whole operational period. PN mainly occurred caused by the inhibitory effect of FNA on nitrite oxidizing bacteria (NOB). Once HNO2 concentration was negligible, NH4+ was fully oxidized to NO3− in spite of the presence of FA. The use of biomass acclimated to ammonium as inoculum avoided a possible effect of FA on NOB activity. PMID:29018815

Influence of the type of aqueous sodium silicate on the stabilization and rheology of kaolin clay suspensions

NASA Astrophysics Data System (ADS)

Izak, Piotr; Ogłaza, Longin; Mozgawa, Włodzimierz; Mastalska-Popławska, Joanna; Stempkowska, Agata

2018-05-01

To avoid agglomeration and sedimentation of grains, ceramic slurries should be modified by stabilizers in order to increase the electrostatic interactions between the dispersed particles. In this study we present the spectral analysis of aqueous sodium silicates obtained by different synthesis methods and their influence on the rheological properties of kaolin based slurries. Infrared and Raman spectra can be used to describe the structure of silicate structural units present in aqueous sodium silicates. It was confirmed that the best stabilization results possess aqueous sodium silicates of the silicate moduli of about 2 and the optimal concentration of the used fluidizer is 0.3 wt% to the kaolin clay dry mass. One of the most important conclusions is that the synthesis method of the fluidizer has no significant effect on its stabilization properties but used medium does create adequate stabilization mechanism depending on the silicate structures present in the sodium silicate solution.

Removal of Historic Low-Level Radioactive Sediment from the Port Hope Harbour - 13314

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kolberg, Mark; Case, Glenn; Ferguson Jones, Andrea

2013-07-01

At the Port Hope Harbour, located on the north shore of Lake Ontario, the presence of low-level radioactive sediment, resulting from a former radium and uranium refinery that operated alongside the Harbour, currently limits redevelopment and revitalization opportunities. These waste materials contain radium-226, uranium, arsenic and other contaminants. Several other on-land locations within the community of Port Hope are also affected by the low-level radioactive waste management practices of the past. The Port Hope Project is a community initiated undertaking that will result in the consolidation of an estimated 1.2 million cubic metres of the low-level radioactive waste from themore » various sites in Port Hope into a new engineered above ground long-term waste management facility. The remediation of the estimated 120,000 m{sup 3} of contaminated sediments from the Port Hope Harbour is one of the more challenging components of the Port Hope Project. Following a thorough review of various options, the proposed method of contaminated sediment removal is by dredging. The sediment from the dredge will then be pumped as a sediment-water slurry mixture into geo-synthetic containment tubes for dewatering. Due to the hard substrate below the contaminated sediment, the challenge has been to set performance standards in terms of low residual surface concentrations that are attainable in an operationally efficient manner. (authors)« less

Pyrethroid sorption to Sacramento River suspended solids and bed sediments.

PubMed

Fojut, Tessa L; Young, Thomas M

2011-04-01

Sorption of pyrethroid insecticides to solid materials will typically dominate the fate and transport of these hydrophobic compounds in aquatic environments. Batch reactor isotherm experiments were performed with bifenthrin and λ-cyhalothrin with suspended material and bed sediment collected from the Sacramento River, California, USA. These batch reactor experiments were performed with low spiking concentrations and a long equilibration time (28 d) to be more relevant to environmental conditions. Sorption to suspended material and bed sediment was compared to examine the role of differential sorption between these phases in the environmental transport of pyrethroids. The equilibrium sorption data were fit to the Freundlich isotherm model and fit with r(2)  > 0.87 for all experiments. Freundlich exponents ranged from 0.72 ± 0.19 to 1.07 ± 0.050, indicating sorption nonlinearity for some of the experimental conditions and linearity for others over the concentration range tested. The Freundlich capacity factors were larger for the suspended solids than for the bed sediments, and the suspended material had a higher specific surface area and higher organic carbon content compared to the bed sediment. Calculated organic carbon-normalized distribution coefficients were larger than those previously reported in the literature, by approximately an order of magnitude, and ranged from 10(6.16) to 10(6.68) at an equilibrium aqueous concentration of 0.1 µg/L. Higher than expected sorption of pyrethroids to the tested materials may be explained by sorption to black carbon and/or mineral surfaces. Copyright © 2011 SETAC.

Testing of various membranes for use in a novel sediment porewater isolation chamber for infaunal invertebrate exposure to PCBs.

PubMed

Coleman, Jessica G; Lotufo, Guilherme R; Kennedy, Alan J; Poda, Aimee R; Rushing, Todd S; Ruiz, Carlos E; Bridges, Todd S

2014-07-01

In benthic sediment bioassays, determining the relative contribution to exposure by contaminants in overlying water, porewater, and sediment particles is technically challenging. The purpose of the present study was to assess the potential for membranes to be utilized as a mechanism to allow freely dissolved hydrophobic organic contaminants into a pathway isolation exposure chamber (PIC) while excluding all sediment particles and dissolved organic carbon (DOC). This investigation was conducted in support of a larger effort to assess contaminant exposure pathways to benthos. While multiple passive samplers exist for estimating concentrations of contaminants in porewater such as those using solid-phase micro extraction (SPME) and polyoxymethylene (POM), techniques to effectively isolate whole organism exposure to porewater within a sediment system are not available. We tested the use of four membranes of different pore sizes (0.1-1.2μm) including nylon, polycarbonate, polyethylsulfone, and polytetrafluoroethylene with a hydrophilic coating. Exposures included both diffusion of radiolabeled and non-labeled contaminants across membranes from aqueous, sediment slurry, and whole sediment sources to assess and evaluate the best candidate membrane. Data generated from the present study was utilized to select the most suitable membrane for use in the larger bioavailability project which sought to assess the relevance of functional ecology in bioavailability of contaminated sediments at remediation sites. The polytetrafluoroethylene membrane was selected for use in the PIC, although exclusion of dissolved organic carbon was not achieved. Published by Elsevier Ltd.

SORPTION OF VINCLOZOLIN AND ATRAZINE ON FOUR GEOSORBENTS

EPA Science Inventory

The objectives of this study were to evaluate the magnitude and kinetics of vinclozolin and atrazine sorption on one surface soil and three freshwater sediments using batch and column techniques. Data from miscible displacement column studies were analyzed using a two-domain, fir...

Investigations on the "Extreme" Microbial Methane Cycle within the Sediments of an Acidic Impoundment of the Inactive Sulfur Bank Mercury Mine: Herman Pit, Clear Lake, California.

NASA Astrophysics Data System (ADS)

Oremland, R. S.; Baesman, S. M.; Miller, L. G.; Wei, J. H. C.; Welander, P. V.

2014-12-01

The inactive Sulfur Bank Mercury Mine is located in a volcanic region having geothermal flow and gas inputs into the Herman Pit impoundment. The acidic (pH 2 - 4) waters of the Herman Pit are permeated by hundreds of continuous flow gas seeps that contain CO2, H2S and CH4. We sampled one seep and found it to be composed of 95 % CO2 and 5 % CH4, in agreement with earlier measurements. Only a trace of ethane (10 - 20 ppm) was found and propane was below detection, resulting in a high CH4/C2H6 + C3H8 ratio of > 5,000, while the δ13CH4 and the δ13CO2 were respectively - 24 and - 11 per mil. Collectively, these results suggested a complex origin for the methane, being made up of a thermogenic component resulting from pyrolysis of buried organics, along with an active methanogenic portion. The relatively 12C-enriched value for the CO2 suggested a reworking of the ebullitive methane by methanotrophic bacteria. We found that dissolved methane in the collected water from 2-4 m depth was high (~ 400 µM), which would support methanotrophy in the lake's aerobic biomes. We therefore tested the ability of bottom sediments to consume methane by conducting aerobic incubations of slurried bottom sediments. Methane was removed from the headspace of live slurries, and subsequent additions of methane to the headspace over the course of 2-3 months resulted in faster removal rates suggesting a buildup of the population of methanotrophs. This activity could be transferred to an artificial medium originally devised for the cultivation of acidophilic iron oxidizing bacteria (Silverman and Lundgren, 1959; J. Bacteriol. 77: 642 - 647), suggesting the possibility of future cultivation of acidophilic methanotrophs. A successful extraction of some hopanoid compounds from the sediments was achieved, although the results were too preliminary at the time of this writing to identify any hopanoids specifically linked to methanotrophic bacteria. Further efforts to amplify functional genes for methane oxidizing bacteria (e.g., pMMO) from extracted sediment DNA are underway.

Evaluation of solar photocatalysis using TiO2 slurry in the inactivation of Cryptosporidium parvum oocysts in water.

PubMed

Abeledo-Lameiro, María Jesús; Ares-Mazás, Elvira; Gómez-Couso, Hipólito

2016-10-01

Cryptosporidium is a genus of enteric protozoan parasites of medical and veterinary importance, whose oocysts have been reported to occur in different types of water worldwide, offering a great resistant to the water treatment processes. Heterogeneous solar photocatalysis using titanium dioxide (TiO2) slurry was evaluated on inactivation of Cryptosporidium parvum oocysts in water. Suspensions of TiO2 (0, 63, 100 and 200mg/L) in distilled water (DW) or simulated municipal wastewater treatment plant (MWTP) effluent spiked with C. parvum oocysts were exposed to simulated solar radiation. The use of TiO2 slurry at concentrations of 100 and 200mg/L in DW yielded a high level of oocyst inactivation after 5h of exposure (4.16±2.35% and 15.03±4.54%, respectively, vs 99.33±0.58%, initial value), representing a good improvement relative to the results obtained in the samples exposed without TiO2 (51.06±9.35%). However, in the assays carried out using simulated MWTP effluent, addition of the photocatalyst did not offer better results. Examination of the samples under bright field and epifluorescence microscopy revealed the existence of aggregates comprising TiO2 particles and parasitic forms, which size increased as the concentration of catalyst and the exposure time increased, while the intensity of fluorescence of the oocyst walls decreased. After photocatalytic disinfection process, the recovery of TiO2 slurry by sedimentation provided a substantial reduction in the parasitic load in treated water samples (57.81±1.10% and 82.10±2.64% for 200mg/L of TiO2 in DW and in simulated MWTP effluent, respectively). Although further studies are need to optimize TiO2 photocatalytic disinfection against Cryptosporidium, the results obtained in the present study show the effectiveness of solar photocatalysis using TiO2 slurry in the inactivation of C. parvum oocysts in distilled water. Copyright © 2016 Elsevier B.V. All rights reserved.

Multi-stage slurry system used for grinding and polishing materials

DOEpatents

Hed, P. Paul; Fuchs, Baruch A.

2001-01-01

A slurry system draws slurry from a slurry tank via one of several intake pipes, where each pipe has an intake opening at a different depth in the slurry. The slurry is returned to the slurry tank via a bypass pipe in order to continue the agitation of the slurry. The slurry is then diverted to a delivery pipe, which supplies slurry to a polisher. The flow of slurry in the bypass pipe is stopped in order for the slurry in the slurry tank to begin to settle. As the polishing continues, slurry is removed from shallower depths in order to pull finer grit from the slurry. When the polishing is complete, the flow in the delivery pipe is ceased. The flow of slurry in the bypass pipe is resumed to start agitating the slurry. In another embodiment, the multiple intake pipes are replaced by a single adjustable pipe. As the slurry is settling, the pipe is moved upward to remove the finer grit near the top of the slurry tank as the polishing process continues.

Evidence for the Existence of Autotrophic Nitrate-Reducing Fe(II)-Oxidizing Bacteria in Marine Coastal Sediment

PubMed Central

Laufer, Katja; Røy, Hans; Jørgensen, Bo Barker

2016-01-01

ABSTRACT Nitrate-reducing Fe(II)-oxidizing microorganisms were described for the first time ca. 20 years ago. Most pure cultures of nitrate-reducing Fe(II) oxidizers can oxidize Fe(II) only under mixotrophic conditions, i.e., when an organic cosubstrate is provided. A small number of nitrate-reducing Fe(II)-oxidizing cultures have been proposed to grow autotrophically, but unambiguous evidence for autotrophy has not always been provided. Thus, it is still unclear whether or to what extent Fe(II) oxidation coupled to nitrate reduction is an enzymatically catalyzed and energy-yielding autotrophic process or whether Fe(II) is abiotically oxidized by nitrite from heterotrophic nitrate reduction. The aim of the present study was to find evidence for the existence of autotrophic nitrate-reducing Fe(II) oxidizers in coastal marine sediments. Microcosm incubations showed that with increasing incubation times, the stoichiometric ratio of reduced nitrate/oxidized Fe(II) [NO3−reduced/Fe(II)oxidized] decreased, indicating a decreasing contribution of heterotrophic denitrification and/or an increasing contribution of autotrophic nitrate-reducing Fe(II) oxidation over time. After incubations of sediment slurries for >10 weeks, nitrate-reducing activity ceased, although nitrate was still present. This suggests that heterotrophic nitrate reduction had ceased due to the depletion of readily available organic carbon. However, after the addition of Fe(II) to these batch incubation mixtures, the nitrate-reducing activity resumed, and Fe(II) was oxidized, indicating the activity of autotrophic nitrate-reducing Fe(II) oxidizers. The concurrent reduction of 14C-labeled bicarbonate concentrations unambiguously proved that autotrophic C fixation occurred during Fe(II) oxidation and nitrate reduction. Our results clearly demonstrated that autotrophic nitrate-reducing Fe(II)-oxidizing bacteria were present in the investigated coastal marine sediments. IMPORTANCE Twenty years after the discovery of nitrate-reducing Fe(II) oxidizers, it is still controversially discussed whether autotrophic nitrate-reducing Fe(II)-oxidizing microorganisms exist and to what extent Fe(II) oxidation in this reduction/oxidation process is enzymatically catalyzed or which role abiotic side reactions of Fe(II) with reactive N species play. Most pure cultures of nitrate-reducing Fe(II) oxidizers are mixotrophic; i.e., they need an organic cosubstrate to maintain their activity over several cultural transfers. For the few existing autotrophic isolates and enrichment cultures, either the mechanism of nitrate-reducing Fe(II) oxidation is not known or evidence for their autotrophic lifestyle is controversial. In the present study, we provide evidence for the existence of autotrophic nitrate-reducing Fe(II) oxidizers in coastal marine sediments. The evidence is based on stoichiometries of nitrate reduction and Fe(II) oxidation determined in microcosm incubations and the incorporation of carbon from CO2 under conditions that favor the activity of nitrate-reducing Fe(II) oxidizers. PMID:27496777

SLURRY MIX EVAPORATOR BATCH ACCEPTABILITY AND TEST CASES OF THE PRODUCT COMPOSITION CONTROL SYSTEM WITH THORIUM AS A REPORTABLE ELEMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.

2010-10-07

The Defense Waste Processing Facility (DWPF), which is operated by Savannah River Remediation, LLC (SRR), has recently begun processing Sludge Batch 6 (SB6) by combining it with Frit 418 at a nominal waste loading (WL) of 36%. A unique feature of the SB6/Frit 418 glass system, as compared to the previous glass systems processed in DWPF, is that thorium will be a reportable element (i.e., concentrations of elemental thorium in the final glass product greater than 0.5 weight percent (wt%)) for the resulting wasteform. Several activities were initiated based upon this unique aspect of SB6. One of these was anmore » investigation into the impact of thorium on the models utilized in DWPF's Product Composition and Control System (PCCS). While the PCCS is described in more detail below, for now note that it is utilized by Waste Solidification Engineering (WSE) to evaluate the acceptability of each batch of material in the Slurry Mix Evaporator (SME) before this material is passed on to the melter. The evaluation employs models that predict properties associated with processability and product quality from the composition of vitrified samples of the SME material. The investigation of the impact of thorium on these models was conducted by Peeler and Edwards [1] and led to a recommendation that DWPF can process the SB6/Frit 418 glass system with ThO{sub 2} concentrations up to 1.8 wt% in glass. Questions also arose regarding the handling of thorium in the SME batch acceptability process as documented by Brown, Postles, and Edwards [2]. Specifically, that document is the technical bases of PCCS, and while Peeler and Edwards confirmed the reliability of the models, there is a need to confirm that the current implementation of DWPF's PCCS appropriately handles thorium as a reportable element. Realization of this need led to a Technical Task Request (TTR) prepared by Bricker [3] that identified some specific SME-related activities that the Savannah River National Laboratory (SRNL) was requested to conduct. SRNL issued a Task Technical and Quality Assurance (TT&QA) plan [4] in response to the SRR request. The conclusions provided in this report are that no changes need to be made to the SME acceptability process (i.e., no modifications to WSRC-TR-95-00364, Revision 5, are needed) and no changes need to be made to the Product Composition Control System (PCCS) itself (i.e. the spreadsheet utilized by Waste Solidification Engineering (WSE) for acceptability decisions does not require modification) in response to thorium becoming a reportable element for DWPF operations. In addition, the inputs and results for the two test cases requested by WSE for use in confirming the successful activation of thorium as a reportable element for DWPF operations during the processing of SB6 are presented in this report.« less

Influence of Polycarboxylate Superplasticizers on Rheological Properties of Cement Slurries Used in Drilling Technologies / Wpływ Superplastyfikatorów Z Grupy Polikarboksylanów Na Właściwości Reologiczne Zaczynów Cementowych Stosowanych W Technologiach Wiertniczych

NASA Astrophysics Data System (ADS)

Stryczek, Stanisław; Wiśniowski, Rafał; Gonet, Andrzej; Złotkowski, Albert; Ziaja, Jan

2013-09-01

Sealing slurries, mainly the cement-based ones, are concentrated dispersive systems, containing solid particles of considerably developed specific surface. Rheologically, such systems are very complex. This also stems from the fact that the rheological properties have a significant effect on: • additives and admixtures modifying technological properties of fresh and set slurries, • chemically complex mechanism of hydration in a slurry in a function of time. Special attention should paid to plasticizing (plasticizers PL) and liquefying (traditional and new- -generation superplasticizers SP) admixtures affecting the modification and optimization of rheological properties of fresh cement slurries as far as providing efficiency of sealing of casing pipes is concerned. Laboratory analyses were focused on proving the following thesis: properly selected type of superplasticizer [by BASF Polska Sp.z o.o. (The Chemical Company) - Admixtures for Concrete Division] advantageously affects the rheological parameters of sealing slurry based on metallurgical cement CEM III /A 32,5. The following variables were used in the analyses: • type of superplasticizer, • type of batch fluid. The laboratory experiments were made on superplasticizers produced by BASF: • SKY 501, • SKY 503, • SKY 591, • ACE 430, • Glenium 115. The superplasticizer concentration in the slurry was 0.5 wt% (as compared with mass of dry cement). Water to cement ratio for the analyzed sealing slurries was equal to 0.5. The sealing slurries were made of metallurgical cement CEM III/A 32,5 N-LH/HSR/N Lafarge Cement S.A. in Małogoszcz. Zaczyny uszczelniające, a zwłaszcza typu cementowego, są skoncentrowanymi układami dyspersyjnymi, zawierającymi cząstki stałe o znacznie rozwiniętej powierzchni właściwej. Układy takie pod względem reologicznym należą do niezwykle złożonych. Wynika to między innymi z faktu, że na właściwości reologiczne w sposób istotny wpływają: • dodatki i domieszki modyfikujące właściwości technologiczne świeżych i stwardniałych zaczynów, • złożony chemicznie mechanizm reakcje hydratacji zachodzące w zaczynie w funkcji czasu. Na szczególną uwagę ze względu na zapewnienie skuteczność uszczelniania kolumn rur okładzinowych w otworach wiertniczych zasługują domieszki uplastyczniające (plastyfikatory PL) i upłynniające (superplastyfikatory SP typu tradycyjnego oraz nowej generacji) wpływające na modyfikację oraz optymalizację cech reologicznych świeżych zaczynów uszczelniających. Przeprowadzone badania laboratoryjne miały na celu udowodnianie następującej tezy: odpowiednio dobrany rodzaj superplastyfikatorów [firmy BASF Polska Sp.z o.o. ( The Chemical Company) - Dział Domieszek do Betonu], wpływa korzystnie na parametry reologiczne zaczynu uszczelniającego sporządzanego na osnowie cementu hutniczego CEM III /A 32,5. W przeprowadzanych badaniach zmiennymi były: • rodzaj superplastyfikatora, • rodzaj cieczy zarobowej. W badaniach laboratoryjnych zastosowano następujące superplastyfikatory firmy BASF: • SKY 501, • SKY 503, • SKY 591, • ACE 430, • Glenium 115. Koncentracja superplastyfikatora w zaczynie wynosiła: 0,5% wagowo (w stosunku do masy suchego cementu). Współczynnik wodno-cementowy dla badanych zaczynów uszczelniających wynosił: 0,5. Do sporządzania zaczynów uszczelniających stosowano cement hutniczy klasy CEM III/A 32,5 N-LH/ HSR/NA - Cementownia Małogoszcz, Grupa Lafarge Cement S.A. w Małogoszczy.

Hyalella IQ Toxicity Test{trademark} as a predictor of whole sediment toxicity with diversely contaminated sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douglas, W.S.; Hayes, K.R.

1994-12-31

The IQ TOXICITY TEST{trademark} is a toxicity screening test that evaluates the organism`s galactosidase enzyme system functionality as a predictor of acute toxicity. Organisms are exposed to a potentially toxic solution for approximately one hour. Following the exposure, the organisms are exposed to a slurry of a galactoside sugar tagged with a fluorescent marker (methylumbelliferyl galactoside) for 15--20 minutes. A black light can then be used to examine whether the hemolymph of the organism contains free umbelliferone, which brightly fluoresces. The organisms are then scored as ``on`` or ``off`` with respect to free umbelliferone. This endpoint can then be usedmore » to calculate an EC50, which is comparable to a whole effluent, pure compound, or sediment toxicity test. Slightly different methodologies are used for different toxicity test organisms. The objective of this presentation is to discuss the use of the IQ{trademark} methodology with porewater extract exposures of the amphipod Hyalella azteca as a predictor of results of whole sediment toxicity tests. The results of over thirty 10 and 28-day whole sediment toxicity tests and the concurrent Hyalella azteca 10 TOXICITY TESTS{trademark} are compared and discussed. The use of screening tests as a reduced cost method for initial site assessment will be discussed.« less

DWPF SIMULANT CPC STUDIES FOR SB7B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D.

2011-11-01

Lab-scale DWPF simulations of Sludge Batch 7b (SB7b) processing were performed. Testing was performed at the Savannah River National Laboratory - Aiken County Technology Laboratory (SRNL-ACTL). The primary goal of the simulations was to define a likely operating window for acid stoichiometry for the DWPF Sludge Receipt and Adjustment Tank (SRAT). In addition, the testing established conditions for the SRNL Shielded Cells qualification simulation of SB7b-Tank 40 blend, supported validation of the current glass redox model, and validated the coupled process flowsheet at the nominal acid stoichiometry. An acid window of 105-140% by the Koopman minimum acid (KMA) equation (107-142%more » DWPF Hsu equation) worked for the sludge-only flowsheet. Nitrite was present in the SRAT product for the 105% KMA run at 366 mg/kg, while SME cycle hydrogen reached 94% of the DWPF Slurry Mix Evaporator (SME) cycle limit in the 140% KMA run. The window was determined for sludge with added caustic (0.28M additional base, or roughly 12,000 gallons 50% NaOH to 820,000 gallons waste slurry). A suitable processing window appears to be 107-130% DWPF acid equation for sludge-only processing allowing some conservatism for the mapping of lab-scale simulant data to full-scale real waste processing including potentially non-conservative noble metal and mercury concentrations. This window should be usable with or without the addition of up to 7,000 gallons of caustic to the batch. The window could potentially be wider if caustic is not added to SB7b. It is recommended that DWPF begin processing SB7b at 115% stoichiometry using the current DWPF equation. The factor could be increased if necessary, but changes should be made with caution and in small increments. DWPF should not concentrate past 48 wt.% total solids in the SME cycle if moderate hydrogen generation is occurring simultaneously. The coupled flowsheet simulation made more hydrogen in the SRAT and SME cycles than the sludge-only run with the same acid stoichiometric factor. The slow acid addition in MCU seemed to alter the reactions that consumed the small excess acid present such that hydrogen generation was promoted relative to sludge-only processing. The coupled test reached higher wt.% total solids, and this likely contributed to the SME cycle hydrogen limit being exceeded at 110% KMA. It is clear from the trends in the SME processing GC data, however, that the frit slurry formic acid contributed to driving the hydrogen generation rate above the SME cycle limit. Hydrogen generation rates after the second frit addition generally exceeded those after the first frit addition. SRAT formate loss increased with increasing acid stoichiometry (15% to 35%). A substantial nitrate gain which was observed to have occurred after acid addition (and nitrite destruction) was reversed to a net nitrate loss in runs with higher acid stoichiometry (nitrate in SRAT product less than sum of sludge nitrate and added nitric acid). Increased ammonium ion formation was also indicated in the runs with nitrate loss. Oxalate loss on the order 20% was indicated in three of the four acid stoichiometry runs and in the coupled flowsheet run. The minimum acid stoichiometry run had no indicated loss. The losses were of the same order as the official analytical uncertainty of the oxalate concentration measurement, but were not randomly distributed about zero loss, so some actual loss was likely occurring. Based on the entire set of SB7b test data, it is recommended that DWPF avoid concentrating additional sludge solids in single SRAT batches to limit the concentrations of noble metals to SB7a processing levels (on a grams noble metal per SRAT batch basis). It is also recommended that DWPF drop the formic acid addition that accompanies the process frit 418 additions, since SME cycle data showed considerable catalytic activity for hydrogen generation from this additional acid (about 5% increase in stoichiometry occurred from the frit formic acid). Frit 418 also does not appear to need formic acid addition to prevent gel formation in the frit slurry. Simulant processing was successful using 100 ppm of 747 antifoam added prior to nitric acid instead of 200 ppm. This is a potential area for DWPF to cut antifoam usage in any future test program. An additional 100 ppm was added before formic acid addition. Foaming during formic acid addition was not observed. No build-up of oily or waxy material was observed in the off-gas equipment. Lab-scale mercury stripping behavior was similar to SB6 and SB7a. More mercury was unaccounted for as the acid stoichiometry increased.« less

Methane and sulfate dynamics in sediments from mangrove-dominated tropical coastal lagoons, Yucatan, Mexico

USGS Publications Warehouse

Chuang, P. C.; Young, Megan B.; Dale, Andrew W.; Miller, Laurence G.; Herrera-Silveira, Jorge A.; Paytan, Adina

2016-01-01

Porewater profiles in sediment cores from mangrove-dominated coastal lagoons (Celestún and Chelem) on the Yucatán Peninsula, Mexico, reveal the widespread coexistence of dissolved methane and sulfate. This observation is interesting since dissolved methane in porewaters is typically oxidized anaerobically by sulfate. To explain the observations we used a numerical transport-reaction model that was constrained by the field observations. The model suggests that methane in the upper sediments is produced in the sulfate reduction zone at rates ranging between 0.012 and 31 mmol m−2 d−1, concurrent with sulfate reduction rates between 1.1 and 24 mmol SO42− m−2 d−1. These processes are supported by high organic matter content in the sediment and the use of non-competitive substrates by methanogenic microorganisms. Indeed sediment slurry incubation experiments show that non-competitive substrates such as trimethylamine (TMA) and methanol can be utilized for microbial methanogenesis at the study sites. The model also indicates that a significant fraction of methane is transported to the sulfate reduction zone from deeper zones within the sedimentary column by rising bubbles and gas dissolution. The shallow depths of methane production and the fast rising methane gas bubbles reduce the likelihood for oxidation, thereby allowing a large fraction of the methane formed in the sediments to escape to the overlying water column.

Stable carbon isotope fractionation during bacterial acetylene fermentation: Potential for life detection in hydrocarbon-rich volatiles of icy planet(oid)s

USGS Publications Warehouse

Miller, Laurence; Baesman, Shaun; Oremland, Ron

2015-01-01

We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus.

Degradation of crude 4-MCHM (4-methylcyclohexanemethanol) in sediments from Elk River, West Virginia

USGS Publications Warehouse

Cozzarelli, Isabelle M.; Akob, Denise M.; Baedecker, Mary; Spencer, Tracey; Jaeschke, Jeanne B.; Dunlap, Darren S.; Mumford, Adam C.; Poret-Peterson, Amisha T.; Chambers, Douglas B.

2017-01-01

In January 2014, approximately 37 800 L of crude 4-methylcyclohexanemethanol (crude MCHM) spilled into the Elk River, West Virginia. To understand the long-term fate of 4-MCHM, we conducted experiments under environmentally relevant conditions to assess the potential for the 2 primary compounds in crude MCHM (1) to undergo biodegradation and (2) for sediments to serve as a long-term source of 4-MCHM. We developed a solid phase microextraction (SPME) method to quantify the cis- and trans-isomers of 4-MCHM. Autoclaved Elk River sediment slurries sorbed 17.5% of cis-4-MCHM and 31% of trans-4-MCHM from water during the 2-week experiment. Sterilized, impacted, spill-site sediment released minor amounts of cis- and up to 35 μg/L of trans-4-MCHM into water, indicating 4-MCHM was present in sediment collected 10 months post spill. In anoxic microcosms, 300 μg/L cis- and 150 μg/L trans-4-MCHM degraded to nondetectable levels in 8–13 days in both impacted and background sediments. Under aerobic conditions, 4-MCHM isomers degraded to nondetectable levels within 4 days. Microbial communities at impacted sites differed in composition compared to background samples, but communities from both sites shifted in response to crude MCHM amendments. Our results indicate that 4-MCHM is readily biodegradable under environmentally relevant conditions.

Characterization and Modeling of Settling, Consolidation, and Suspension to Optimize Sediment Retention of Sediment Diversions for Coastal Restoration

NASA Astrophysics Data System (ADS)

Sha, X.; Xu, K.; Bentley, S. J.; Robichaux, P.

2016-02-01

Although many studies of sediment diversions have been conducted on the Mississippi Delta, relatively less attention has been paid to understanding sediment retention and basic cohesive sedimentation processes in receiving basins. Our research evaluates long-term (up to six months) sedimentation processes through various laboratory experiments, especially cohesive sediment settling, consolidation and resuspension and their impacts on sediment retention. Bulk sediment samples were collected from West Bay, near Head of Passes of the Mississippi Delta, and the Big Mar basin that receive water and sediment from the Caernarvon Diversion in the upper Breton Sound region of Louisiana, USA. A-230-cm tall settling column with nine sampling ports at 15 cm intervals was used to measure the consolidation for four initial sediment concentrations (10-120 kg m-3) with two salinities (1 ppt & 5 ppt). Samples of sediment slurry were taken from every port at different time intervals up to 15 days or longer (higher concentration needs longer time to consolidate) to record concentrations gravimetrically. A 200 cm long tube was connected to a 50 cm long core chamber to accumulate at least a 10 cm thick sediment column for erosion tests. A dual-core Gust Erosion Microcosm System was employed to measure time-series (0.5, 1, 2, 3, 4, 5, 6 months) erodibility at seven shear stress regimes (0.01-0.60 Pa). Our preliminary results show a significant decrease of erodibility with time and high concentration (120g/L). Salinity impacted on sediment behavior in consolidation experiments. Our study reveals that more enclosed receiving basins, intermittent openings of diversions, or reduced shear stress due to man-made structure all can potentially reduce cohesive sediment erosion in coastal Louisiana. Further results will be analyzed to determine the model constants. Consolidating rates and corresponding erosional changes will be determined to optimize sediment retention in coastal protection.

Isolation, Characterization, and Polyaromatic Hydrocarbon Degradation Potential of Aerobic Bacteria from Marine Macrofaunal Burrow Sediments and Description of Lutibacterium anuloederans gen. nov., sp. nov., and Cycloclasticus spirillensus sp. nov.†

PubMed Central

Chung, W. K.; King, G. M.

2001-01-01

Two new polyaromatic hydrocarbon-degrading marine bacteria have been isolated from burrow wall sediments of benthic macrofauna by using enrichments on phenanthrene. Strain LC8 (from a polychaete) and strain M4-6 (from a mollusc) are aerobic and gram negative and require sodium chloride (>1%) for growth. Both strains can use 2- and 3-ring polycyclic aromatic hydrocarbons as their sole carbon and energy sources, but they are nutritionally versatile. Physiological and phylogenetic analyses based on 16S ribosomal DNA sequences suggest that strain M4-6 belongs to the genus Cycloclasticus and represents a new species, Cycloclasticus spirillensus sp. nov. Strain LC8 appears to represent a new genus and species, Lutibacterium anuloederans gen. nov., sp. nov., within the Sphingomonadaceae. However, when inoculated into sediment slurries with or without exogenous phenanthrene, only L. anuloederans appeared to sustain a significant phenanthrene uptake potential throughout a 35-day incubation. In addition, only L. anuloederans appeared to enhance phenanthrene degradation in heavily contaminated sediment from Little Mystic Cove, Boston Harbor, Boston, Mass. PMID:11722910

Stable isotope fractionation of selenium by natural microbial consortia

USGS Publications Warehouse

Ellis, A.S.; Johnson, T.M.; Herbel, M.J.; Bullen, T.D.

2003-01-01

The mobility and bioavailability of Se depend on its redox state, and reduction of Se oxyanions to less mobile, reduced species controls transport of this potentially toxic element in the environment. Stable isotope fractionation of Se is currently being developed as an indicator of Se immobilization through reduction. In this study, Se isotope fractionation resulting from reduction of Se(VI) and Se(IV) oxyanions by natural microbial consortia was measured in sediment slurry experiments under nearly natural conditions, with no substrate added. Experiments were conducted with a wide range of initial Se concentrations and with sediment and water from three locations with contrasting environmental settings. The products of Se(VI) and Se(IV) reduction were enriched in the lighter isotopes relative to the reactants. Shifts of -2.60/00 to -3.10/00 and -5.50/00 to -5.70/00, respectively, were observed in the 80Se/76Se ratio. These isotopic fractionations did not depend significantly on initial Se concentrations, which were varied from 22 μg/l to 8 mg/l, or on geochemical differences among the sediments. These results provide estimates of Se isotope fractionation in organic-rich wetland environments but may not be appropriate for substrate-poor aquifers and marine sediments.

Dissolved inorganic nitrogen composition, transformation, retention, and transport in naturally phosphate-rich and phosphate-poor tropical streams

USGS Publications Warehouse

Triska, F.J.; Pringle, C.M.; Zellweger, G.W.; Duff, J.H.; Avanzino, R.J.

1993-01-01

In Costa Rica, the Salto River is enriched by geothermal-based soluble reactive phosphorus (SRP), which raises the concentration up to 200 ??g/L whereas Pantano Creek, an unimpacted tributary, has an SRP concentration <10 ??g/L. Ammonium concentration in springs adjacent to the Salto and Pantano was typically greater than channel water (13 of 22 locations) whereas nitrate concentration was less (20 of 22 locations). Ground waters were typically high in ammonium relative to nitrate whereas channel waters were high in nitrate relative to ammonium. Sediment slurry studies indicated nitrification potential in two sediment types, firm clay (3.34 ??g N.cm-3.d-1) and uncompacted organic-rich sediment (1.76 ??g N.cm-3.d-1). Ammonium and nitrate amendments to each stream separately resulted in nitrate concentrations in excess of that expected after correlation for dilution using a conservative tracer. SRP concentration was not affected by DIN amendment to either stream. SRP concentration in the Pantano appeared to be regulated by abiotic sediment exchange reactions. DIN composition and concentration were regulated by a combination of biotic and abiotic processes. -from Authors

Selenate reduction to elemental selenium by anaerobic bacteria in sediments and culture: biogeochemical significance of a novel, sulfate-independent respiration

USGS Publications Warehouse

Oremland, Ronald S.; Hollibaugh, James T.; Maest, Ann S.; Presser, Theresa S.; Miller, Laurence G.; Culbertson, Charles W.

1989-01-01

Interstitial water profiles of SeO42−, SeO32−, SO42−, and Cl− in anoxic sediments indicated removal of the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, a complete reductive removal of SeO42− occurred under anaerobic conditions, was more rapid with H2 or acetate, and was inhibited by O2, NO3−, MnO2, or autoclaving but not by SO42− or FeOOH. Oxidation of acetate in sediments could be coupled to selenate but not to molybdate. Reduction of selenate to elemental selenium was determined to be the mechanism for loss from solution. Selenate reduction was inhibited by tungstate and chromate but not by molybdate. A small quantity of the elemental selenium precipitated into sediments from solution could be resolublized by oxidation with either nitrate or FeOOH, but not with MnO2. A bacterium isolated from estuarine sediments demonstrated selenate-dependent growth on acetate, forming elemental selenium and carbon dioxide as respiratory end products. These results indicate that dissimilatory selenate reduction to elemental selenium is the major sink for selenium oxyanions in anoxic sediments. In addition, they suggest application as a treatment process for removing selenium oxyanions from wastewaters and also offer an explanation for the presence of selenite in oxic waters.

Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

PubMed Central

Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

2016-01-01

Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12–15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

Linking microbial heterotrophic activity and sediment lithology in oxic, oligotrophic sub-seafloor sediments of the north atlantic ocean.

PubMed

Picard, Aude; Ferdelman, Timothy G

2011-01-01

Microbial heterotrophic activity was investigated in oxic sub-seafloor sediments at North Pond, a sediment pond situated at 23°N on the western flank of the Mid-Atlantic Ridge. The North Pond sediments underlie the oligotrophic North Atlantic Gyre at 4580-m water depth and cover a 7-8 million-year-old basaltic crust aquifer through which seawater flows. Discrete samples for experimentation were obtained from up to ~9 m-long gravity cores taken at 14 stations in the North Pond area. Potential respiration rates were determined in sediment slurries incubated under aerobic conditions with (14)C-acetate. Microbial heterotrophic activity, as defined by oxidation of acetate to CO(2) (with O(2) as electron acceptor), was detected in all 14 stations and all depths sampled. Potential respiration rates were generally low (<0.2 nmol of respired acetate cm(-3) d(-1)) in the sediment, but indicate that microbial heterotrophic activity occurs in deep-sea, oxic, sub-seafloor sediments. Furthermore, discernable differences in activity existed between sites and within given depth profiles. At seven stations, activity was increased by several orders of magnitude at depth (up to ~12 nmol of acetate respired cm(-3) d(-1)). We attempted to correlate the measures of activity with high-resolution color and element stratigraphy. Increased activities at certain depths may be correlated to variations in the sediment geology, i.e., to the presence of dark clay-rich layers, of sandy layers, or within clay-rich horizons presumably overlying basalts. This would suggest that the distribution of microbial heterotrophic activity in deeply buried sediments may be linked to specific lithologies. Nevertheless, high-resolution microbial examination at the level currently enjoyed by sedimentologists will be required to fully explore this link.

Linking Microbial Heterotrophic Activity and Sediment Lithology in Oxic, Oligotrophic Sub-Seafloor Sediments of the North Atlantic Ocean

PubMed Central

Picard, Aude; Ferdelman, Timothy G.

2011-01-01

Microbial heterotrophic activity was investigated in oxic sub-seafloor sediments at North Pond, a sediment pond situated at 23°N on the western flank of the Mid-Atlantic Ridge. The North Pond sediments underlie the oligotrophic North Atlantic Gyre at 4580-m water depth and cover a 7–8 million-year-old basaltic crust aquifer through which seawater flows. Discrete samples for experimentation were obtained from up to ~9 m-long gravity cores taken at 14 stations in the North Pond area. Potential respiration rates were determined in sediment slurries incubated under aerobic conditions with 14C-acetate. Microbial heterotrophic activity, as defined by oxidation of acetate to CO2 (with O2 as electron acceptor), was detected in all 14 stations and all depths sampled. Potential respiration rates were generally low (<0.2 nmol of respired acetate cm−3 d−1) in the sediment, but indicate that microbial heterotrophic activity occurs in deep-sea, oxic, sub-seafloor sediments. Furthermore, discernable differences in activity existed between sites and within given depth profiles. At seven stations, activity was increased by several orders of magnitude at depth (up to ~12 nmol of acetate respired cm−3 d−1). We attempted to correlate the measures of activity with high-resolution color and element stratigraphy. Increased activities at certain depths may be correlated to variations in the sediment geology, i.e., to the presence of dark clay-rich layers, of sandy layers, or within clay-rich horizons presumably overlying basalts. This would suggest that the distribution of microbial heterotrophic activity in deeply buried sediments may be linked to specific lithologies. Nevertheless, high-resolution microbial examination at the level currently enjoyed by sedimentologists will be required to fully explore this link. PMID:22207869

Sulfide and methane production in sewer sediments: Field survey and model evaluation.

PubMed

Liu, Yiwen; Tugtas, A Evren; Sharma, Keshab R; Ni, Bing-Jie; Yuan, Zhiguo

2016-02-01

Sewer sediment processes have been reported to significantly contribute to overall sulfide and methane production in sewers, at a scale comparable to that of sewer biofilms. The physiochemical and biological characteristics of sewer sediments are heterogeneous; however, the variability of in-sediments sulfide and methane production rates among sewers has not been assessed to date. In this study, five sewer sediment samples were collected from two cities in Australia with different climatic conditions. Batch assays were conducted to determine the rates of sulfate reduction and methane production under different flow velocity (shear stress) conditions as well as under completely mixed conditions. The tests showed substantial and variable sulfate reduction and methane production activities among different sediments. Sulfate reduction and methane production from sewer sediments were confirmed to be areal processes, and were dependent on flow velocity/shear stress. Despite of the varying characteristics and reactions kinetics, the sulfate reduction and methane production processes in all sediments could be well described by a one-dimensional sewer sediment model recently developed based on results obtained from a laboratory sewer sediment reactor. Model simulations indicated that the in-situ contribution of sewer sediment emissions could be estimated without the requirement of measuring the specific sediment characteristics or the sediment depths. Copyright © 2015 Elsevier Ltd. All rights reserved.

Predicting characteristics of rainfall driven estrogen runoff and transport from swine AFO spray fields.

PubMed

Lee, Boknam; Kullman, Seth W; Yost, Erin E; Meyer, Michael T; Worley-Davis, Lynn; Williams, C Michael; Reckhow, Kenneth H

2015-11-01

Animal feeding operations (AFOs) have been implicated as potentially major sources of estrogenic contaminants into the aquatic environment due to the relatively minimal treatment of waste and potential mobilization and transport of waste components from spray fields. In this study a Bayesian network (BN) model was developed to inform management decisions and better predict the transport and fate of natural steroidal estrogens from these sites. The developed BN model integrates processes of surface runoff and sediment loss with the modified universal soil loss equation (MUSLE) and the soil conservation service curve number (SCS-CN) runoff model. What-if scenario simulations of lagoon slurry wastes to the spray fields were conducted for the most abundant natural estrogen estrone (E1) observed in the system. It was found that E1 attenuated significantly after 2 months following waste slurry application in both spring and summer seasons, with the overall attenuation rate predicted to be higher in the summer compared to the spring. Using simulations of rainfall events in conjunction with waste slurry application rates, it was predicted that the magnitude of E1 runoff loss is significantly higher in the spring as compared to the summer months, primarily due to spray field crop management plans. Our what-if scenario analyses suggest that planting Bermuda grass in the spray fields is likely to reduce runoff losses of natural estrogens near the water bodies and ecosystems, as compared to planting of soybeans. Copyright © 2015 Elsevier B.V. All rights reserved.

Predicting Characteristics of Rainfall Driven Estrogen Runoff and Transport from Swine AFO Spray Fields

PubMed Central

Lee, Boknam; Kullman, Seth W.; Yost, Erin E.; Meyer, Michael T.; Worley-Davis, Lynn; Williams, C. Michael; Reckhow, Kenneth H.

2017-01-01

Animal feeding operations (AFOs) have been implicated as potentially major sources of estrogenic contaminants into the aquatic environment due to the relatively minimal treatment of waste and potential mobilization and transport of waste components from spray fields. In this study a Bayesian network (BN) model was developed to inform management decisions and better predict the transport and fate of natural steroidal estrogens from these sites. The developed BN model integrates processes of surface runoff and sediment loss with the modified universal soil loss equation (MUSLE) and the soil conservation service curve number (SCS-CN) runoff model. What-if scenario simulations of lagoon slurry wastes to the spray fields were conducted for the most abundant natural estrogen estrone (E1) observed in the system. It was found that E1 attenuated significantly after 2 months following waste slurry application in both spring and summer seasons, with the overall attenuation rate predicted to be higher in the summer compared to the spring. Using simulations of rainfall events in conjunction with waste slurry application rates, it was predicted that the magnitude of E1 runoff loss is significantly higher in the spring as compared to the summer months, primarily due to spray field crop management plans. Our what-if scenario analyses suggest that planting Bermuda grass in the spray fields is likely to reduce runoff losses of natural estrogens near the water bodies and ecosystems, as compared to planting of soybeans. PMID:26102057

Controls of Sediment Nitrogen Dynamics in Tropical Coastal Lagoons

PubMed Central

Enrich-Prast, Alex; Figueiredo, Viviane; Esteves, Francisco de Assis; Nielsen, Lars Peter

2016-01-01

Sediment denitrification rates seem to be lower in tropical environments than in temperate environments. Using the isotope pairing technique, we measured actual denitrification rates in the sediment of tropical coastal lagoons. To explain the low denitrification rates observed at all study sites (<5 μmol N2 m-2 h-1), we also evaluated potential oxygen (O2) consumption, potential nitrification, potential denitrification, potential anammox, and estimated dissimilatory nitrate (NO3-) reduction to ammonium (NH4+; DNRA) in the sediment. 15NO3- and 15NH4+ conversion was measured in oxic and anoxic slurries from the sediment surface. Sediment potential O2 consumption was used as a proxy for overall mineralization activity. Actual denitrification rates and different potential nitrogen (N) oxidation and reduction processes were significantly correlated with potential O2 consumption. The contribution of potential nitrification to total O2 consumption decreased from contributing 9% at sites with the lowest sediment mineralization rates to less than 0.1% at sites with the highest rates. NO3- reduction switched completely from potential denitrification to estimated DNRA. Ammonium oxidation and nitrite (NO2-) reduction by potential anammox contributed up to 3% in sediments with the lowest sediment mineralization rates. The majority of these patterns could be explained by variations in the microbial environments from stable and largely oxic conditions at low sediment mineralization sites to more variable conditions and the prevalences of anaerobic microorganisms at high sediment mineralization sites. Furthermore, the presence of algal and microbial mats on the sediment had a significant effect on all studied processes. We propose a theoretical model based on low and high sediment mineralization rates to explain the growth, activity, and distribution of microorganisms carrying out denitrification and DNRA in sediments that can explain the dominance or coexistence of DNRA and denitrification processes. The results presented here show that the potential activity of anaerobic nitrate-reducing organisms is not dependent on the availability of environmental NO3-. PMID:27175907

Controls of Sediment Nitrogen Dynamics in Tropical Coastal Lagoons.

PubMed

Enrich-Prast, Alex; Figueiredo, Viviane; Esteves, Francisco de Assis; Nielsen, Lars Peter

2016-01-01

Sediment denitrification rates seem to be lower in tropical environments than in temperate environments. Using the isotope pairing technique, we measured actual denitrification rates in the sediment of tropical coastal lagoons. To explain the low denitrification rates observed at all study sites (<5 μmol N2 m-2 h-1), we also evaluated potential oxygen (O2) consumption, potential nitrification, potential denitrification, potential anammox, and estimated dissimilatory nitrate (NO3-) reduction to ammonium (NH4+; DNRA) in the sediment. 15NO3- and 15NH4+ conversion was measured in oxic and anoxic slurries from the sediment surface. Sediment potential O2 consumption was used as a proxy for overall mineralization activity. Actual denitrification rates and different potential nitrogen (N) oxidation and reduction processes were significantly correlated with potential O2 consumption. The contribution of potential nitrification to total O2 consumption decreased from contributing 9% at sites with the lowest sediment mineralization rates to less than 0.1% at sites with the highest rates. NO3- reduction switched completely from potential denitrification to estimated DNRA. Ammonium oxidation and nitrite (NO2-) reduction by potential anammox contributed up to 3% in sediments with the lowest sediment mineralization rates. The majority of these patterns could be explained by variations in the microbial environments from stable and largely oxic conditions at low sediment mineralization sites to more variable conditions and the prevalences of anaerobic microorganisms at high sediment mineralization sites. Furthermore, the presence of algal and microbial mats on the sediment had a significant effect on all studied processes. We propose a theoretical model based on low and high sediment mineralization rates to explain the growth, activity, and distribution of microorganisms carrying out denitrification and DNRA in sediments that can explain the dominance or coexistence of DNRA and denitrification processes. The results presented here show that the potential activity of anaerobic nitrate-reducing organisms is not dependent on the availability of environmental NO3-.

Minimising alkalinity and pH spikes from Portland cement-bound Bauxsol (seawater-neutralized red mud) pellets for pH circum-neutral waters.

PubMed

Despland, Laure M; Clark, Malcolm W; Aragno, Michel; Vancov, Tony

2010-03-15

Bauxsol reagents (powder, slurry, or pellet forms) are powerful tools in environmental remediation and water and sewage treatment However, when used in circum-neutral water treatments, cement-bound Bauxsol pellets produce a sustained pH and alkalinity spike due to the presence of unreacted CaO in the cement binder. This study developed a pellet treatment system to minimize the alkalinity/pH spike. The recipe for pelletization consisted of Bauxsol powder, ordinary Portland cement (OPC), hydrophilic fumed silica, aluminum powder, a viscosity modifier, and water. Several batches (including different ratios and sizes) were run using modified makeup waters (H(2)0 + CO(2) or NaHCO(3)) or curing brines (CO(2), NaHCO(3), or Mg/CaCl(2)). Alkalinity, pH stability, and slake durability tests were performed on pellets before and/or after curing. The best result for reducing the alkalinity/pH spike was obtained from a MgCl(2), CaCl(2) bath treatment using a Bauxsol:cement ratio of 2.8:1 (pH 8.28; alkalinity 75.1 mg/L) for a 100 g batch or 245:1 (pH 8.05; alkalinity 35.4 mg/L) for a 1 kg batch. Although brine curing does provide a control on pH/alkalinity release, the pellets may still contain unreacted CaO. Therefore, a freshwater rinse of pellets before treating circum-neutral waters is recommended as is the continued investigation of alternative pellet binders.

Defense Waste Processing Facility Simulant Chemical Processing Cell Studies for Sludge Batch 9

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Tara E.; Newell, J. David; Woodham, Wesley H.

The Savannah River National Laboratory (SRNL) received a technical task request from Defense Waste Processing Facility (DWPF) and Saltstone Engineering to perform simulant tests to support the qualification of Sludge Batch 9 (SB9) and to develop the flowsheet for SB9 in the DWPF. These efforts pertained to the DWPF Chemical Process Cell (CPC). CPC experiments were performed using SB9 simulant (SB9A) to qualify SB9 for sludge-only and coupled processing using the nitric-formic flowsheet in the DWPF. Two simulant batches were prepared, one representing SB8 Tank 40H and another representing SB9 Tank 51H. The simulant used for SB9 qualification testing wasmore » prepared by blending the SB8 Tank 40H and SB9 Tank 51H simulants. The blended simulant is referred to as SB9A. Eleven CPC experiments were run with an acid stoichiometry ranging between 105% and 145% of the Koopman minimum acid equation (KMA), which is equivalent to 109.7% and 151.5% of the Hsu minimum acid factor. Three runs were performed in the 1L laboratory scale setup, whereas the remainder were in the 4L laboratory scale setup. Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on nine of the eleven. The other two were SRAT cycles only. One coupled flowsheet and one extended run were performed for SRAT and SME processing. Samples of the condensate, sludge, and off-gas were taken to monitor the chemistry of the CPC experiments.« less

Slicing of silicon into sheet material. Silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project. Third quarterly report, September 20, 1976--December 19, 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holden, S.C.

1976-12-27

The stability of tensioned blades used in multiblade sawing does not seem to be the limitation in cutting with thin blades. So far, 0.010 cm thick blades have been totally unsuccessful. Recently, 0.015 cm blades have proven successful in wafering, offering an 0.005 cm reduction in the silicon used per slice. The failure of thin blades is characterized as a possible result of blade misalignment or from the inherent uncontrollability of the loose abrasive multiblade process. Corrective procedures will be employed in the assembly of packages to eliminate one type of blade misalignment. Two ingots were sliced with the samemore » batch of standard silicon carbide abrasive slurry to determine the useful lifetime of this expendable material. After 250 slices, the cutting efficiency had not degraded. Further tests will be continued to establish the maximum lifetime of both silicon carbide and boron carbide abrasive. Electron microscopy will be employed to evaluate the wear of abrasive particles in the failure of abrasive slurry. The surface damage of silicon wafers has been characterized as predominantly subsurface fracture. Damage with No. 600 SiC is between 10 and 15 microns into the wafer surface. This agrees well with previous investigations of damage from silicon carbide abrasive papers.« less

Co-digestion, biostimulation and bioaugmentation to enhance methanation of brewer's spent grain.

PubMed

Goberna, Marta; Camacho, Maria del Mar; Lopez-Abadia, Juan Antonio; García, Carlos

2013-08-01

More than 300,000 tonnes of brewer's spent grain (BSG) is generated annually during beer production. This protein- and nutrient-rich by-product is mostly employed as an animal feedstuff. However, its marketability is compromised by its rapid deterioration owing to its high humidity and fermentable sugar content. Drying BSG can be achieved using the bio-energy generated from the anaerobic digestion of part of the BSG produced in the same brewery. We employed three types of strategies to enhance the biomethanation of BSG in mesophilic batch incubations. First, we co-digested BSG with peach flesh residues, juice residues, sewage sludge and pig slurry. Second, we supplemented BSG with chemical additives (carbon and energy sources) in order to biostimulate the methane-producing microbial communities. Finally, we used anaerobically acclimatised BSG to augment the initial microbial load in assays digesting BSG either alone or in co-digestion with sewage sludge. All co-substrates assayed were suitable to be fermented in combination with BSG, although methane production was highest for the mixtures with sewage sludge and pig slurry, with their high pH values and nutrient contents. Nine out of 14 combinations of stimulatory chemicals significantly enhanced BSG methanation compared with a non-supplemented control. Overall, bioaugmenting the anaerobic microbial consortia by using fermented BSG as an inoculum when co-digesting BSG with sewage sludge performed best in terms of methane yield.

Effect of Corn Dried Distiller Grains with Solubles (DDGS) in Dairy Cow Diets on Manure Bioenergy Production Potential.

PubMed

Massé, Daniel I; Jarret, Guillaume; Benchaar, Chaouki; Saady, Noori M Cata

2014-03-05

The main objective of this study was to obtain scientifically sound data on the bioenergy potential of dairy manures from cows fed different levels of corn dried distillers grains with solubles (DDGS). Three diets differing in corn DDGS content were formulated: 0% corn DDGS (DDGS0; control diet), 10% corn DDGS (DDGS10) and 30% corn DDGS (DDGS30). Bioenergy production was determined in psychrophilic (25 ± 1 °C) sequencing batch reactors (SBRs) fed 3 g COD L(-1)·day(-1) during a two-week feeding period followed by a two-week react period. Compared to the control diet, adding DDGS10 and DDGS30 to the dairy cow diet increased the daily amount of fat excreted in slurry by 29% and 70%, respectively. The addition of DDGS30 increased the cows' daily production of fresh feces and slurry by 15% and 11%, respectively. Furthermore, the incorporation of DDGS30 in the diet increased the daily amounts of dry matter (DM), volatile solids (VS), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose by 18%, 18%, 30%, 15% and 53%, respectively, compared to the control diet. While the addition of DDGS did not significantly affect the specific CH₄ production per kg VS compared to the control diet, DDGS30 increased the per cow daily CH₄ production by 14% compared to the control diet.

Dechlorination of trichloroethylene formed from 1,1,2,2-tetrachloroethane by dehydrochlorination in Portland cement slurry including Fe(II).

PubMed

Jung, Bahngmi; Batchelor, Bill

2008-03-01

Transformation of 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA) by Fe(II) in 10% cement slurries was characterized using a batch reactor system. 1,1,2,2-TeCA was completely converted to trichloroethylene (TCE) within 1h in all experiments, even in controls with cement that did not include Fe(II). Therefore, complete degradation of 1,1,2,2-TeCA depends on the behavior of TCE. The half-life of TCE was observed to be 15d when concentrations of Fe(II) and 1,1,2,2-TeCA were 98mM and 0.245mM, respectively. The kinetics of TCE removal was observed to be dependent on Fe(II) dose, pH and initial substrate concentration. Pseudo-first-order rate constants linearly increased with Fe(II) dose up to 198mM when initial target concentration was 0.245mM. Pseudo-first-order kinetics generally described the degradation reactions of TCE at a specific initial concentration, but a modified Langmuir-Hinshelwood model was necessary to describe the degradation kinetics of TCE over a wide range of initial concentrations. A surface reaction of TCE on active solids, which were formed from Fe(II) and products of cement hydration appears to control observed TCE degradation kinetics.

THE REDUCTIVE TRANSFORMATION OF PERCHLORATE IN A FRESH WATER SEDIMENT: LABORATORY BATCH STUDIES

EPA Science Inventory

Perchlorate is widely used as a propellant in solid rocket fuel, and has recently been found in ground, surface, and drinking water, in many cases above the interim action level of 18 ppb. Perchlorate is recalcitrant to chemical reduction, however, studies of perchlorate in pure ...

THE REDUCTIVE TRANSFORMATION OF PERCHLORATE IN A FRESH WATER SEDIMENT: LABORATORY BATCH STUDIES.

EPA Science Inventory

Perchlorate is widely used as a propellant in solid rocket fuel, and has recently been found in ground, surface, and drinking water, in many cases above the interim action level of 18 ppb. Perchlorate is recalcitrant to chemical reduction, however, studies of perchlorate in pure ...

Design of a lamella settler for biomass recycling in continuous ethanol fermentation process.

PubMed

Tabera, J; Iznaola, M A

1989-04-20

The design and application of a settler to a continuous fermentation process with yeast recycle were studied. The compact lamella-type settler was chosen to avoid large volumes associated with conventional settling tanks. A rationale of the design method is covered. The sedimentation area was determined by classical batch settling rate tests and sedimentation capacity calculation. Limitations on the residence time of the microorganisms in the settler, rather than sludge thickening considerations, was the approach employed for volume calculation. Fermentation rate tests with yeast after different sedimentation periods were carried out to define a suitable residence time. Continuous cell recycle fermentation runs, performed with the old and new sedimentation devices, show that lamella settler improves biomass recycling efficiency, being the process able to operate at higher sugar concentrations and faster dilution rates.

Bioaccumulation of perfluorochemicals in sediments by the aquatic oligochaete Lumbriculus variegatus.

PubMed

Higgins, Christopher P; McLeod, Pamela B; MacManus-Spencer, Laura A; Luthy, Richard G

2007-07-01

Bioaccumulation of perfluoroalkyl sulfonates, perfluorocarboxylates, and 2-(N-ethylperfluorooctane sulfonamido) acetic acid (N-EtFOSAA) from laboratory-spiked and contaminated field sediments was assessed using the freshwater oligochaete, Lumbriculus variegatus. Semistatic batch experiments were conducted to monitor the biological uptake of these perfluorochemicals (PFCs) over 56 days. The elimination of PFCs was measured as the loss of PFCs in L. variegatus exposed to PFC-spiked sediment for 28 days and then transferred to clean sediment. The resultant data suggest that PFCs in sediments are readily bioavailable and that bioaccumulation from sediments does not continually increase with increasing perfluorocarbon chain length. Perfluorooctane sulfonate (PFOS) and perfluorononanoate were the most bioaccumulative PFCs, as measured by laboratory-based estimated steady-state biota sediment accumulation factors (BSAFs) and BSAFs measured using contaminated field sediments. Elimination rate constants for perfluoroalkyl sulfonates and perfluorocaroboxylates were generally smaller than those previously measured for other organic contaminants. Last, a PFOS precursor, N-EtFOSAA, accumulated in the worm tissues and appeared to undergo biotransformation to PFOS and other PFOS precursors. This suggests that N-EtFOSAA, which has been detected in sediments and sludge often at levels exceeding PFOS, may contribute to the bioaccumulation of PFOS in aquatic organisms.

Warming increases nutrient mobilization and gaseous nitrogen removal from sediments across cascade reservoirs.

PubMed

Zhou, Xingpeng; Chen, Nengwang; Yan, Zhihao; Duan, Shuiwang

2016-12-01

Increases in water temperature, as a result of climate change, may influence biogeochemical cycles, sediment-water fluxes and consequently environmental sustainability. Effects of rising temperature on dynamics of nitrate, nitrite, ammonium, dissolved inorganic nitrogen (DIN), dissolved reactive phosphorus (DRP), dissolved organic carbon (DOC) and gaseous nitrogen (N 2 and N 2 O) were examined in a subtropical river (the Jiulong River, southeast China) by microcosm experiments. Slurry sediments and overlying water were collected from three continuous cascade reservoirs, and laboratory incubations were performed at four temperature gradients (5 °C, 15 °C, 25 °C and 35 °C). Results indicated: (1) warming considerably increased sediment ammonium, DIN and DOC fluxes to overlying water; (2) warming increased retention of nitrate, and to a lesser extent, nitrite, corresponding to increases in N 2 and N 2 O emission; (3) DRP was retained but released from Fe/Al-P enriched sediments at high temperature (35 °C) due to enhanced coupled transformation of carbon and nitrogen with oxygen deficiency. Using relationships between sediment fluxes and temperature, a projected 2.3°C-warming in future would increase ammonium flux from sediment by 7.0%-16.8%, while increasing nitrate flux into sediment by 8.9%-28.6%. Moreover, substrates (e.g., grain size, carbon availability) influenced nutrient delivery and cycling across cascade reservoirs. This study highlights that warming would increase bioreactive nutrient (i.e., ammonium and phosphate) mobilization with limited gaseous N removal from sediments, consequently deteriorating water quality and increasing eutrophication with future climate change. Copyright © 2016 Elsevier Ltd. All rights reserved.

On time discretizations for the simulation of the batch settling-compression process in one dimension.

PubMed

Bürger, Raimund; Diehl, Stefan; Mejías, Camilo

2016-01-01

The main purpose of the recently introduced Bürger-Diehl simulation model for secondary settling tanks was to resolve spatial discretization problems when both hindered settling and the phenomena of compression and dispersion are included. Straightforward time integration unfortunately means long computational times. The next step in the development is to introduce and investigate time-integration methods for more efficient simulations, but where other aspects such as implementation complexity and robustness are equally considered. This is done for batch settling simulations. The key findings are partly a new time-discretization method and partly its comparison with other specially tailored and standard methods. Several advantages and disadvantages for each method are given. One conclusion is that the new linearly implicit method is easier to implement than another one (semi-implicit method), but less efficient based on two types of batch sedimentation tests.

Comparative study of ageing, heat treatment and accelerated carbonation for stabilization of municipal solid waste incineration bottom ash in view of reducing regulated heavy metal/metalloid leaching.

PubMed

Santos, Rafael M; Mertens, Gilles; Salman, Muhammad; Cizer, Özlem; Van Gerven, Tom

2013-10-15

This study compared the performance of four different approaches for stabilization of regulated heavy metal and metalloid leaching from municipal solid waste incineration bottom ash (MSWI-BA): (i) short term (three months) heap ageing, (ii) heat treatment, (iii) accelerated moist carbonation, and (iv) accelerated pressurized slurry carbonation. Two distinct types of MSWI-BA were tested in this study: one originating from a moving-grate furnace incineration operation treating exclusively household refuse (sample B), and another originating from a fluid-bed furnace incineration operation that treats a mixture of household and light industrial wastes (sample F). The most abundant elements in the ashes were Si (20-27 wt.%) and Ca (16-19 wt.%), followed by significant quantities of Fe, Al, Na, S, K, Mg, Ti, and Cl. The main crystalline substances present in the fresh ashes were Quartz, Calcite, Apatite, Anhydrite and Gehlenite, while the amorphous fraction ranged from 56 to 73 wt.%. The leaching values of all samples were compared to the Flemish (NEN 7343) and the Walloon (DIN 38414) regulations from Belgium. Batch leaching of the fresh ashes at natural pH showed that seven elements exceeded at least one regulatory limit (Ba, Cr, Cu, Mo, Pb, Se and Zn), and that both ashes had excess basicity (pH > 12). Accelerated carbonation achieved significant reduction in ash basicity (9.3-9.9); lower than ageing (10.5-12.2) and heat treatment (11.1-12.1). For sample B, there was little distinction between the leaching results of ageing and accelerated carbonation with respect to regulatory limits; however carbonation achieved comparatively lower leaching levels. Heat treatment was especially detrimental to the leaching of Cr. For sample F, ageing was ineffective and heat treatment had marginally better results, while accelerated carbonation delivered the most effective performance, with slurry carbonation meeting all DIN limits. Slurry carbonation was deemed the most effective treatment process, achieving consistently significant leaching stabilization, while also effectively washing out Cl ions, a requirement for the utilization of the ashes in construction applications. The benefits of carbonation were linked to the formation of significant quantities of Ca-carbonates, including appreciable quantities of the Aragonite polymorph formed in the slurry carbonated samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tank 40 Final SB7b Chemical Characterization Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2012-11-06

A sample of Sludge Batch 7b (SB7b) was taken from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). The SB7b WAPS sample was also analyzed for chemical composition including noble metals and fissile constituents. At the Savannah River National Laboratory (SRNL) the 3-L Tank 40 SB7b sample was transferred from the shipping container into a 4-L high density polyethylene bottle and solids were allowed to settle over the weekend. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thoroughmore » mixing of the 3-L sample, a 558 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon vessels and four with NaOH/Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Two Analytical Reference Glass ? 1 (ARG-1) standards were digested along with a blank for each preparation. Each aqua regia digestion and blank was diluted to 1:100 mL with deionized water and submitted to Analytical Development (AD) for inductively coupled plasma ? atomic emission spectroscopy (ICP-AES) analysis, inductively coupled plasma ? mass spectrometry (ICP-MS) analysis, atomic absorption spectroscopy (AA) for As and Se, and cold vapor atomic absorption spectroscopy (CV-AA) for Hg. Equivalent dilutions of the alkali fusion digestions and blank were submitted to AD for ICP-AES analysis. Tank 40 SB7b supernate was collected from a mixed slurry sample in the SRNL Shielded Cells and submitted to AD for ICP-AES, ion chromatography (IC), total base/free OH{sup -}/other base, total inorganic carbon/total organic carbon (TIC/TOC) analyses, and Cs-137 gamma scan. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH-/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the Tank 40 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method.« less

Microbial Formation of Dimethyl Sulfide in Anoxic Sphagnum Peat

PubMed Central

Kiene, R. P.; Hines, M. E.

1995-01-01

Peat bogs dominated by Sphagnum spp. have relatively high areal rates of dimethyl sulfide (DMS) emission to the atmosphere. DMS was produced in anoxic slurries of Sphagnum peat with a linear time course and with an average rate of 40.4 (range, 22.0 to 68.6) nmol per liter of slurry (middot) day(sup-1) observed in nine batches of slurry. Methanethiol (MeSH) was produced at roughly similar rates over the typical 4- to 8-day incubations. DMS and MeSH production in these acidic (pH 4.2 to 4.6) peats were biological, as they were stopped completely by autoclaving and inhibited strongly by addition of antibiotics and 500 (mu)M chloroform. Endogenous DMS production may be due to the degradation of S-methyl-methionine, dimethyl sulfoxide, or methoxyaromatic compounds (e.g., syringic acid), each of which stimulated DMS formation when added at 5 to 10 (mu)M concentrations. However, on the basis of the high rates of thiol (MeSH and ethanethiol) methylation activity that we observed and the availability of endogenous MeSH, we suggest that methylation of MeSH is the major pathway leading to DMS formation in anaerobic peat. Solid-phase adsorption of MeSH plays a key role in its availability for biomethylation reactions. Additions of acetate (1.5 mM) or compounds which could cause acetate to accumulate (e.g., glucose, alanine, and 2-bromoethanesulfonate) suppressed DMS formation. It is likely that acetogenic bacteria are involved in DMS formation, but our data are insufficient to allow firm conclusions about the metabolic pathways or organisms involved. Our observations are the first which point to the methylation of MeSH as the major mechanism for endogenous DMS production in any environment. The rates of net DMS production observed are sufficient to explain the relatively high fluxes of DMS emitted to the atmosphere from Sphagnum sp.-dominated wetlands. PMID:16535080

Smart operation of nitritation/denitritation virtually abolishes nitrous oxide emission during treatment of co-digested pig slurry centrate.

PubMed

Peng, Lai; Carvajal-Arroyo, José M; Seuntjens, Dries; Prat, Delphine; Colica, Giovanni; Pintucci, Cristina; Vlaeminck, Siegfried E

2017-12-15

The implementation of nitritation/denitritation (Nit/DNit) as alternative to nitrification/denitrification (N/DN) is driven by operational cost savings, e.g. 1.0-1.8 EUR/ton slurry treated. However, as for any biological nitrogen removal process, Nit/DNit can emit the potent greenhouse gas nitrous oxide (N 2 O). Challenges remain in understanding formation mechanisms and in mitigating the emissions, particularly at a low ratio of organic carbon consumption to nitrogen removal (COD rem /N rem ). In this study, the centrate (centrifuge supernatant) from anaerobic co-digestion of pig slurry was treated in a sequencing batch reactor. The process removed approximately 100% of ammonium a satisfactory nitrogen loading rate (0.4 g N/L/d), with minimum nitrite and nitrate in the effluent. Substantial N 2 O emission (around 17% of the ammonium nitrogen loading) was observed at the baseline operational condition (dissolved oxygen, DO, levels averaged at 0.85 mg O 2 /L; COD rem /N rem of 2.8) with ∼68% of the total emission contributed by nitritation. Emissions increased with higher nitrite accumulation and lower organic carbon to nitrogen ratio. Yet, higher DO levels (∼2.2 mg O 2 /L) lowered the aerobic N 2 O emission and weakened the dependency on nitrite concentration, suggesting a shift in N 2 O production pathway. The most effective N 2 O mitigation strategy combined intermittent patterns of aeration, anoxic feeding and anoxic carbon dosage, decreasing emission by over 99% (down to ∼0.12% of the ammonium nitrogen loading). Without anaerobic digestion, mitigated Nit/DNit decreases the operational carbon footprint with about 80% compared to N/DN. With anaerobic digestion included, about 4 times more carbon is sequestered. In conclusion, the low COD rem /N rem feature of Nit/DNit no longer offsets its environmental sustainability provided the process is smartly operated. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simulation of Industrial Wastewater Treatment from the Suspended Impurities into the Flooded Waste Mining Workings

NASA Astrophysics Data System (ADS)

Bondareva, L.; Zakharov, Yu; Goudov, A.

2017-04-01

The paper is dedicated to the mathematical model of slurry wastewater treatment and disposal in a flooded mine working. The goal of the research is to develop and analyze the mathematical model of suspended impurities flow and distribution. Impurity sedimentation model is under consideration. Due to the sediment compaction problem solution domain can be modified. The model allows making a forecast whether volley emission is possible. Numerical simulation results for “Kolchuginskaya” coal mine presented. Impurity concentration diagrams in outflow corresponding to the real full-scale data obtained. Safely operation time mine workings like a wastewater treatment facility are estimated. The carried out calculations demonstrate that the method of industrial wastewater treatment in flooded waste mine workings can be put into practice but it is very important to observe all the processes going on to avoid volley emission of accumulated impurities.

Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s

PubMed Central

Baesman, Shaun M.; Oremland, Ronald S.

2015-01-01

Abstract We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2 compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus. Key Words: Acetylene—Fermentation—Isotope fractionation—Enceladus—Life detection. Astrobiology 15, 977–986. PMID:26539733

Experiments on Transitional Subaqueous Density Flows and Resulting Sediment Deposits

NASA Astrophysics Data System (ADS)

Barnaal, Z. D.; Parker, G.

2016-12-01

Much remains unknown regarding the sedimentary deposits of submarine gravity flows. Flows with large concentrations of suspended sediment may transition from a more turbulent to a more coherent flow type. Such transitional flows may be produced when turbulence becomes suppressed due to entrainment of cohesive sediment or from flow deceleration. Argillaceous sandstones and linked turbidite-debrites are types of submarine sediment deposits in a category known as hybrid event beds, and are interpreted to be emplaced by transitional regime flows (Talling, 2007; Davis, 2009; Haughton, 2009; Hodgson, 2009; Sumner, 2009; Baas, 2011; Lee, 2013; and Talling, 2013). Here we report on the physical modelling of such transitional flows. The sediment consists of mixtures of non-cohesive silica flour with a median grain size of 30 microns and kaolin clay with a median size of 4 microns. These sediments were mixed in ratios including 100%, 70%, 60%, 50%, 30% and 0% kaolin. Total volume concentration of the input slurry varied from 0.01 to 0.2, allowing coverage of wide range of transitional flow types. The flow passed over a 4.9-m-long bed with a slope of 7 degrees, and continued another 4.9 m over a horizontal bed before exiting the tank. Measurements of flow velocity profiles, flow concentrations, deposit geometry, and deposit grain-size distributions were conducted. The results of experiments help us to better understand the rheology, and to determine the structure and patterns of deposits including argillaceous sandstones.

Anaerobic biodegradation of PAHs in mangrove sediment with amendment of NaHCO3.

PubMed

Li, Chun-Hua; Wong, Yuk-Shan; Wang, Hong-Yuan; Tam, Nora Fung-Yee

2015-04-01

Mangrove sediment is unique in chemical and biological properties. Many of them suffer polycyclic aromatic hydrocarbon (PAH) contamination. However, the study on PAH biological remediation for mangrove sediment is deficient. Enriched PAH-degrading microbial consortium and electron acceptor amendment are considered as two effective measures. Compared to other electron acceptors, the study on CO2, which is used by methanogens, is still seldom. This study investigated the effect of NaHCO3 amendment on the anaerobic biodegradation of four mixed PAHs, namely fluorene (Fl), phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr), with or without enriched PAH-degrading microbial consortium in mangrove sediment slurry. The trends of various parameters, including PAH concentrations, microbial population size, electron-transport system activities, electron acceptor and anaerobic gas production were monitored. The results revealed that the inoculation of enriched PAH-degrading consortium had a significant effect with half lives shortened by 7-13 days for 3-ring PAHs and 11-24 days for 4-ring PAHs. While NaHCO3 amendment did not have a significant effect on the biodegradation of PAHs and other parameters, except that CO2 gas in the headspace of experimental flasks was increased. One of the possible reasons is that mangrove sediment contains high concentrations of other electron acceptors which are easier to be utilized by anaerobic bacteria, the other one is that the anaerobes in mangrove sediment can produce enough CO2 gas even without adding NaHCO3. Copyright © 2015. Published by Elsevier B.V.

Continuous magnetic separator and process

DOEpatents

Oder, Robin R.; Jamison, Russell E.

2008-04-22

A continuous magnetic separator and process for separating a slurry comprising magnetic particles into a clarified stream and a thickened stream. The separator has a container with a slurry inlet, an overflow outlet for the discharge of the clarified slurry stream, and an underflow outlet for the discharge of a thickened slurry stream. Magnetic particles in the slurry are attracted to, and slide down, magnetic rods within the container. The slurry is thus separated into magnetic concentrate and clarified slurry. Flow control means can be used to control the ratio of the rate of magnetic concentrate to the rate of clarified slurry. Feed control means can be used to control the rate of slurry feed to the slurry inlet.

Acetate concentrations and oxidation in salt marsh sediments

NASA Technical Reports Server (NTRS)

1992-01-01

Acetate concentrations and rates of acetate oxidation and sulfate reduction were measured in S. alterniflora sediments in New Hampshire and Massachusetts. Pore water extracted from cores by squeezing or centrifugation contained in greater than 0.1 mM acetate and, in some instances, greater than 1.0 mM. Pore water sampled nondestructively contained much less acetate, often less than 0.01 mM. Acetate was associated with roots, and concentrations varied with changes in plant physiology. Acetate turnover was very low whether whole core or slurry incubations were used. Radiotracers injected directly into soils yielded rates of sulfate reduction and acetate oxidation not significantly different from core incubation techniques. Regardless of incubation method, acetate oxidation did not account for a substantial percentage of sulfate reduction. These results differ markedly from data for unvegetated coastal sediments where acetate levels are low, oxidation rate constants are high, and acetate oxication rates greatly exceed rates of sulfate reduction. The discrepancy between rates of acetate oxidation and sulfate reduction in these marsh soils may be due either to the utilization of substrates other than acetate by sulfate reducers or artifacts associated with measurements of organic utilization by rhizosphere bacteria. Care must be taken when interpreting data from salt marsh sediments since the release of material from roots during coring may affect the concentrations of certain compounds as well as influencing results obtained when sediment incubations are employed.

Energy Saving Melting and Revert Reduction Technology: Innovative Semi-Solid Metal (SSM) Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diran Apelian

2012-08-15

Semi-solid metal (SSM) processing has emerged as an attractive method for near-net-shape manufacturing due to the distinct advantages it holds over conventional near-net-shape forming technologies. These advantages include lower cycle time, increased die life, reduced porosity, reduced solidification shrinkage, improved mechanical properties, etc. SSM processing techniques can not only produce the complex dimensional details (e.g. thin-walled sections) associated with conventional high-pressure die castings, but also can produce high integrity castings currently attainable only with squeeze and low-pressure permanent mold casting processes. There are two primary semi-solid processing routes, (a) thixocasting and (b) rheocasting. In the thixocasting route, one starts frommore » a non-dendritic solid precursor material that is specially prepared by a primary aluminum manufacturer, using continuous casting methods. Upon reheating this material into the mushy (a.k.a. "two-phase") zone, a thixotropic slurry is formed, which becomes the feed for the casting operation. In the rheocasting route (a.k.a. "slurry-on-demand" or "SoD"), one starts from the liquid state, and the thixotropic slurry is formed directly from the melt via careful thermal management of the system; the slurry is subsequently fed into the die cavity. Of these two routes, rheocasting is favored in that there is no premium added to the billet cost, and the scrap recycling issues are alleviated. The CRP (Trade Marked) is a process where the molten metal flows through a reactor prior to casting. The role of the reactor is to ensure that copious nucleation takes place and that the nuclei are well distributed throughout the system prior to entering the casting cavity. The CRP (Trade Marked) has been successfully applied in hyper-eutectic Al-Si alloys (i.e., 390 alloy) where two liquids of equal or different compositions and temperatures are mixed in the reactor and creating a SSM slurry. The process has been mostly used for hypo-eutectic Al-Si alloys (i.e., 356, 357, etc.) where a single melt passes through the reactor. In addition, the CRP (Trade Marked) was designed to be flexible for thixocasting or rheocasting applications as well as batch or continuous casting. Variable heat extraction rates can be obtained by controlling either the superheat of the melt, the temperature of the channel system, or the temperature of the reactor. This program had four main objectives all of which were focused on a mechanistic understanding of the process in order to be able to scale it up, to develop it into a robust process,and for SSM processing to be commercially used.« less

Effect of organic loading on nitrification and denitrification in a marine sediment microcosm

USGS Publications Warehouse

Caffrey, J.M.; Sloth, N.P.; Kaspar, H.F.; Blackburn, T.H.

1993-01-01

The effects of organic additions on nitrification and denitrification were examined in sediment microcosms. The organic material, heat killed yeast, had a C/N ratio of 7.5 and was added to sieved, homogenized sediments. Four treatments were compared: no addition (control, 30 g dry weight (dw) m-2 mixed throughout the 10 cm sediment column (30 M), 100 g dw m-2 mixed throughout sediments (100M), and 100 g dw m-2 mixed into top 1 cm (100S). After the microcosms had been established for 7-11 days, depth of O2 penetration, sediment-water fluxes and nitrification rates were measured. Nitrification rates were measured using three different techniques: N-serve and acetylene inhibition in intact cores, and nitrification potentials in slurries. Increased organic additions decreased O2 penetration from 2.7 to 0.2 mm while increasing both O2 consumption, from 30 to 70 mmol O2 m-2 d-1, and NO3- flux into sediments. Nitrification rates in intact cores were similar for the two methods. Highest rates occurred in the 30 M treatment, while the lowest rate was measured in the 100S treatment. Total denitrification rates (estimated from nitrification and nitrate fluxes) increased with increased organic addition, because of the high concentrations of NO3- (40 ??M) in the overlying water. The ratio of nitrification: denitrification was used as an indication of the importance of nitrification as the NO3- supply for denitrification. This ratio decreased from 1.55 to 0.05 with increased organic addition.

Monitoring Uranium Transformations Determined by the Evolution of Biogeochemical Processes: Design of Mixed Batch Reactor and Column Studies at Oak Ridge National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Criddle, Craig S.; Wu, Weimin

2013-04-17

With funds provided by the US DOE, Argonne National Laboratory subcontracted the design of batch and column studies to a Stanford University team with field experience at the ORNL IFRC, Oak Ridge, TN. The contribution of the Stanford group ended in 2011 due to budget reduction in ANL. Over the funded research period, the Stanford research team characterized ORNL IFRC groundwater and sediments and set up microcosm reactors and columns at ANL to ensure that experiments were relevant to field conditions at Oak Ridge. The results of microcosm testing demonstrated that U(VI) in sediments was reduced to U(IV) with themore » addition of ethanol. The reduced products were not uraninite but were instead U(IV) complexes associated with Fe. Fe(III) in solid phase was only partially reduced. The Stanford team communicated with the ANL team members through email and conference calls and face to face at the annual ERSP PI meeting and national meetings.« less

Comparison and analysis of organic components of biogas slurry from eichhornia crassipes solms and corn straw biogas slurry

NASA Astrophysics Data System (ADS)

Li, Q.; Li, Y. B.; Liu, Z. H.; Min, J.; Cui, Y.; Gao, X. H.

2017-11-01

Biogas slurry is one of anaerobic fermentations, and biomass fermentation biogas slurries with different compositions are different. This paper mainly presents through the anaerobic fermentation of Eichhornia crassipes solms biogas slurry and biogas slurry of corn straw, the organic components of two kinds of biogas slurry after extraction were compared by TLC, HPLC and spectrophotometric determination of nucleic acid and protein of two kinds of biogas slurry organic components, and analyzes the result of comparison.

Influence of environmental parameters and of their interactions on the release of metal(loid)s from a construction material in hydraulic engineering.

PubMed

Schmukat, A; Duester, L; Goryunova, E; Ecker, D; Heininger, P; Ternes, T A

2016-03-05

Besides the leaching behaviour of a construction material under standardised test-specific conditions with laboratory water, for some construction materials it is advisable to test their environmental behaviour also under close to end use conditions. The envisaged end use combined with the product characteristics (e.g. mineral phases) is decisive for the choice of environmental factors that may change the release of substance that potentially cause adverse environmental effects (e.g. fertilisation or ecotoxicity). At the moment an experimental link is missing between mono-factorial standardised test systems and non standardised complex incubation experiments such as mesocosms which are closer to environmental conditions. Multi-factorial batch experiments may have the potential to close the gap. To verify this, batch experiments with copper slag were performed which is used as armour stones in hydraulic engineering. Design of experiments (DoE) was applied to evaluate the impact of pH, ionic strength, temperature and sediment content on the release of As, Cu, Mo, Ni, Pb, Sb and Zn. The study shows that release and sediment-eluent partitioning of metal(loid)s are impacted by interactions between the studied factors. Under the prevalent test conditions sediment acts as a sink enhancing most strongly the release of elements from the material. Copyright © 2015 Elsevier B.V. All rights reserved.

Thiol-Based Selective Extraction Assay to Comparatively Assess Bioavailable Mercury in Sediments

PubMed Central

Ticknor, Jonathan L.; Kucharzyk, Katarzyna H.; Porter, Kaitlyn A.; Deshusses, Marc A.; Hsu-Kim, Heileen

2015-01-01

Abstract Bioaccumulation of methylmercury in the aquatic food web is governed in part by the methylation of inorganic divalent mercury (Hg(II)) by anaerobic microorganisms. In sulfidic settings, a small fraction of total Hg(II) is typically bioavailable to methylating microorganisms. Quantification of this fraction is difficult due to uncertainties in the speciation of Hg(II) and the mechanisms of uptake by methylating microbes. However, recent studies have shown that the bioavailable fraction is likely to include a portion of Hg(II) associated with solid phases, that is, nanostructured mercuric sulfides. Moreover, addition of thiols to suspensions of methylating cultures coincides with increased uptake into cells and methylmercury production. Here, we present a thiol-based selective extraction assay to provide information on the bioavailable Hg fraction in sediments. In the procedure, sediment samples were exposed to a nitrogen-purged solution of glutathione (GSH) for 30 min and the amount of GSH-leachable mercury was quantified. In nine sediment samples from a marine location, the relative GSH-leachable mercury concentration was strongly correlated to the relative amount of methylmercury in the sediments (r2=0.91, p<0.0001) across an order of magnitude of methylmercury concentration values. The approach was further applied to anaerobic sediment slurry microcosm experiments in which sediments were cultured under the same microbial growth conditions but were amended with multiple forms of Hg with a known spectrum of bioavailability. GSH-leachable Hg concentrations increased with observed methylmercury concentrations in the microcosms, matching the trend of species bioavailability in our previous work. Results suggest that a thiol-based selective leaching approach is an improvement compared with other proposed methods to assess Hg bioavailability in sediment and that this approach could provide a basis for comparison of sites where Hg methylation is a concern. PMID:26244001

Nature and classification of waterlain glaciogenic sediments, exemplified by Pleistocene, Late Paleozoic and Late Precambrian deposits

NASA Astrophysics Data System (ADS)

Gravenor, C. P.; von Brunn, V.; Dreimanis, A.

1984-03-01

This study of waterlain glaciogenic sediments is designed to present both a review and new information on glaciogenic subaquatic deposits of differing age in a number of localities in North and South America and South Africa. The Late Paleozoic glaciogenic deposits of the ParanáBasin in Brazil and the Karoo Basin of South Africa are singled out for special attention as they show a reasonably complete lateral sequence of terrestrial to off-shore glaciogenic sedimentation. Although the environment of subaquatic glaciogenic sedimentation varies from one area to the next, certain common elements are found which can be used to develop a generalized model for both glaciomarine and glaciolacustrine sedimentation. For descriptive purposes, the model is divided into two broad categories: a shelf facies and a basinal facies. The shelf facies is marked by massive diamicton(ite) which may be 200 m or more in thickness and which is frequently overlain by a complex of clastic sediments consisting primarily of gravity and fluid flows. The basinal facies is marked by products of subaquatic slumps and more distal turbidites and glaciomarine sediments. New terminology is introduced. The massive diamicton(ite), which is diagnostic of the shelf facies, probably represents deposition from the base of active ice in a subaquatic environment and is termed undermelt diamicton(ite). The gravity and fluid flows which are usually found overlying undermelt diamicton(ite) and in the basinal facies are subdivided into six categories: glaciogenic subaquatic outwash, glaciogenic suspension flow, glaciogenic chaotic debris flow, glaciogenic subaquatic debris flow, glaciogenic slurry flow and glaciogenic turbidity flow. The relative abundance of undermelt diamicton(ite) and the various types of gravity and fluid flows can be used to define inner shelf, outer shelf, inner basin and outer basin facies of glaciomarine sedimentation.

Effects of inorganic electron acceptors on methanogenesis and methanotrophy and on the community structure of bacteria and archaea in sediments of a boreal lake

NASA Astrophysics Data System (ADS)

Rissanen, Antti J.; Karvinen, Anu; Nykänen, Hannu; Peura, Sari; Tiirola, Marja; Mäki, Anita; Kankaala, Paula

2016-04-01

Lake sediments are globally significant sources of CH4 to the atmosphere, but the factors controlling the production and consumption of CH4 in these systems are understudied. Increasing availability of electron acceptors (EA) (other than CO2) in sediments can decrease or even suppress CH4 production by diverting the electron flow (from H2 and organic substances) from methanogenic to other anaerobic respiration pathways. However, whether these changes in microbial function extend down to changes in the structure of microbial communities is not known. Also anaerobic oxidation of methane (AOM) could be enhanced by increased availability of EAs (SO42-, NO3-, Fe3+ and Mn4+), but information on the role of this process in lake sediments is scarce. We studied the effects of inorganic EAs on the potential for CH4 production and consumption and on the structure of microbial communities in sediments of a boreal lake. Anoxic slurries of sediment samples collected from two depths (0 - 10 cm; 10 - 30 cm) of the profundal zone of a boreal, mesotrophic Lake Ätäskö, were amended with 1) CH4 or with CH4 and either 2) 10 mM Mn4+, 3) 10 mM Fe3+, 4) O2 or 5) CH2F2 (inhibitor of aerobic methane oxidation) and incubated at +10° C for up to 4 months. Furthermore, slurries from the 10 - 30 cm layer were amended with CH4 and either 6) 2 mM NO3- or 7) 2 mM SO42- and incubated at +4 ° C for up to 14 months. The processes were measured using 13C-labelling and by concentration measurements of CH4 and CO2. Effects of treatments 1-3 on microbial communities were also analysed by next-generation sequencing of 16S rRNA, as well as methyl coenzyme-M reductase gene amplicons and mRNA transcripts. CH4 production (max. 83 nmol gdw-1d-1) took place in the anaerobic treatments but was generally decreased by the addition of NO3-, SO42-, Fe3+ and Mn4+. Although the structure of sediment archaeal community was resistant to Fe3+/Mn4+ - additions, slight changes in the structure of bacterial community occurred. Besides decreasing the availability of methanogenic substrates, the Mn4+/Fe3+ - induced changes in the bacterial community also probably decreased the H2:acetate - ratio in the substrate pool. This led to increase in the relative activity (mRNA level) of some operational taxonomic units assigned to aceticlastic Methanosaetaceae and decrease in the relative activity of hydrogenotrophic Methanoregulaceae in the sediment. CH4 oxidation (0.02 - 0.30 nmol gdw-1d-1 in anaerobic and 18 - 73 nmol gdw-1d-1in aerobic treatments) took place without EA additions and was enhanced only by O2. This suggests decoupling of the process from the reduction of other inorganic EAs. The results also indicate that Fe3+/Mn4+ - reduction did not increase CH4 oxidation via increased availability of SO42- by cryptic sulfur cycle or via increased availability of organic EAs. Furthermore, ANME - archaea were only ≤ 3% of sediment archaeal community and their relative activity was decreased during incubations. Thus, EA driving CH4 oxidation in the anoxic sediments of the lake remains unknown or the process was methanogen-driven via trace methane oxidation.

Coal slurry fuel supply and purge system

DOEpatents

McDowell, Robert E.; Basic, Steven L.; Smith, Russel M.

1994-01-01

A coal slurry fuel supply and purge system for a locomotive engines is disclosed which includes a slurry recirculation path, a stand-by path for circulating slurry during idle or states of the engine when slurry fuel in not required by the engine, and an engine header fluid path connected to the stand-by path, for supplying and purging slurry fuel to and from fuel injectors. A controller controls the actuation of valves to facilitate supply and purge of slurry to and from the fuel injectors. A method for supplying and purging coal slurry in a compression ignition engine is disclosed which includes controlling fluid flow devices and valves in a plurality of fluid paths to facilitate continuous slurry recirculation and supply and purge of or slurry based on the operating state of the engine.

Transient Fluvial Response to Alpine Deglaciation, Mount Rainier, WA: Geomorphic Process Domains and Proglacial Flux Controls on Channel Evolution.

NASA Astrophysics Data System (ADS)

Beyeler, J. D.; Montgomery, D.; Kennard, P. M.

2016-12-01

Downwasting of all glaciers on the flanks of Mount Rainier, WA, in recent decades has debuttressed Little Ice Age glaciogenic sediments driving proglacial responses to regionally warming climate. Rivers draining the deglaciating edifice are responding to paraglacial sedimentation processes through transient storage of retreat-liberated sediments in aggrading (e.g., >5m) fluvial networks with widening channel corridors (i.e., 50-150%) post-LIA (ca., 1880-1910 locally). We hypothesize that the downstream transmission of proglacial fluxes (i.e., sediment and water) through deglaciating alpine terrain is a two-step geomorphic process. The ice-proximal portion of the proglacial system is dominated by the delivery of high sediment-to-water ratio flows (i.e., hyperconcentrated and debris slurries) and sediment retention by in-channel accumulation (e.g., confined debris fans within channel margins of valley segments) exacerbated by recruitment and accumulation of large wood (e.g., late seral stage conifers), whereas ice-distal fluvial reworking of transient sediment accumulations generates downstream aggradation. Historical Carbon River observations show restricted ice-proximal proglacial aggradation until a mainstem avulsion in 2009 initiated incision into sediment accumulations formed in recent decades, which is translating into aggradation farther down the network. Surficial morphology mapped with GPS, exposed subsurface sedimentology, and preliminary dating of buried trees suggest a transitional geomorphic process zone has persisted along the proglacial Carbon River through recent centuries and prior to the ultimate LIA glaciation. Structure-from-motion DEM differencing through the 2016 water year shows discrete zones of proglacial evolution through channel-spanning bed aggradation forced by interactions between large wood and sediment-rich flows that transition to fluvial process dominance as sediment is transported downstream. Long-term DEM differencing suggests these are persistent geomorphic processes as rivers respond to alpine deglaciation. This process-based study implies downstream river flooding in deglaciating alpine terrain globally is driven by glaciogenic sediment release and downstream channel aggradation irrespective of changes in discharge.

Structure-processing correlations and mechanical properties in freeze-cast Ti-6Al-4V with highly aligned porosity and a lightweight Ti-6Al-4V-PMMA composite with excellent energy absorption capability

DOE PAGES

Weaver, Jordan S.; Kalidindi, Surya R.; Wegst, Ulrike G. K.

2017-02-12

In contrast to freeze-cast ceramics and polymers, few freeze-cast metals have been described, to date. This systematic study on structure-processing correlations in freeze-cast Ti-6Al-4V scaffolds reports how processing parameters determine the architecture formed during the directional solidification of water-based metal slurries and after sintering. Additionally, sedimentation in the slurry during freezing and volume shrinkage during burnout and sintering were found to significantly affect both structure and properties of the scaffolds. In using two freezing rates, 1 and 10 °C min -1, two water-based polymer solutions as binders (chitosan and carboxymethyl cellulose) and two different metal volume fractions in the slurry,more » 20 and 30 vol%, Ti-6Al-4V scaffolds could be prepared with pore length, width, and porosity ranging from 41 to 523 μm, 14.5–76.5 μm, and 65 to 34%, respectively. Their compressive strength, stiffness, and toughness (work to 20% strain) fall in the range of 83–412 MPa, 7–29 GPa, and 14–122 MJ m -3, respectively. In order to improve the properties a select composition was infiltrated with poly(methyl methacrylate). This increased the average yield strength by a factor of 2.3 from 83 to 193 MPa and the average toughness (work to 50% strain) by a factor of 2.7 from 28.1 to 76.8 MJ m -3.« less

Structure-processing correlations and mechanical properties in freeze-cast Ti-6Al-4V with highly aligned porosity and a lightweight Ti-6Al-4V-PMMA composite with excellent energy absorption capability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weaver, Jordan S.; Kalidindi, Surya R.; Wegst, Ulrike G. K.

In contrast to freeze-cast ceramics and polymers, few freeze-cast metals have been described, to date. This systematic study on structure-processing correlations in freeze-cast Ti-6Al-4V scaffolds reports how processing parameters determine the architecture formed during the directional solidification of water-based metal slurries and after sintering. Additionally, sedimentation in the slurry during freezing and volume shrinkage during burnout and sintering were found to significantly affect both structure and properties of the scaffolds. In using two freezing rates, 1 and 10 °C min -1, two water-based polymer solutions as binders (chitosan and carboxymethyl cellulose) and two different metal volume fractions in the slurry,more » 20 and 30 vol%, Ti-6Al-4V scaffolds could be prepared with pore length, width, and porosity ranging from 41 to 523 μm, 14.5–76.5 μm, and 65 to 34%, respectively. Their compressive strength, stiffness, and toughness (work to 20% strain) fall in the range of 83–412 MPa, 7–29 GPa, and 14–122 MJ m -3, respectively. In order to improve the properties a select composition was infiltrated with poly(methyl methacrylate). This increased the average yield strength by a factor of 2.3 from 83 to 193 MPa and the average toughness (work to 50% strain) by a factor of 2.7 from 28.1 to 76.8 MJ m -3.« less

Geochemical heterogeneity in a sand and gravel aquifer: Effect of sediment mineralogy and particle size on the sorption of chlorobenzenes

USGS Publications Warehouse

Barber, Larry B.; Thurman, E. Michael; Runnells, Donald D.

1992-01-01

The effect of particle size, mineralogy and sediment organic carbon (SOC) on sorption of tetrachlorobenzene and pentachlorobenzene was evaluated using batch-isotherm experiments on sediment particle-size and mineralogical fractions from a sand and gravel aquifer, Cape Cod, Massachusetts. Concentration of SOC and sorption of chlorobenzenes increase with decreasing particle size. For a given particle size, the magnetic fraction has a higher SOC content and sorption capacity than the bulk or non-magnetic fractions. Sorption appears to be controlled by the magnetic minerals, which comprise only 5–25% of the bulk sediment. Although SOC content of the bulk sediment is <0.1%, the observed sorption of chlorobenzenes is consistent with a partition mechanism and is adequately predicted by models relating sorption to the octanol/water partition coefficient of the solute and SOC content. A conceptual model based on preferential association of dissolved organic matter with positively-charged mineral surfaces is proposed to describe micro-scale, intergranular variability in sorption properties of the aquifer sediments.

System and method for slurry handling

DOEpatents

Steele, Raymond Douglas; Oppenheim, Judith Pauline

2015-12-29

A system includes a slurry depressurizing system that includes a liquid expansion system configured to continuously receive a slurry at a first pressure and continuously discharge the slurry at a second pressure. For example, the slurry depressurizing system may include an expansion turbine to expand the slurry from the first pressure to the second pressure.

In situ redox manipulation of subsurface sediments from Fort Lewis, Washington: Iron reduction and TCE dechlorination mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

JE Szecsody; JS Fruchter; DS Sklarew

2000-03-21

Pacific Northwest National Laboratory (PNNL) conducted a bench-scale study to determine how effective chemically treated Ft. Lewis sediments can degrade trichloroethylene (TCE). The objectives of this experimental study were to quantify: (1) sediment reduction and oxidation reactions, (2) TCE degradation reactions, and (3) other significant geochemical changes that occurred. Sediment reduction and oxidation were investigated to determine the mass of reducible iron in the Ft. Lewis sediments and the rate of this reduction and subsequent oxidation at different temperatures. The temperature dependence was needed to be able to predict field-scale reduction in the relatively cold ({approximately}11 C) Ft. Lewis aquifer.more » Results of these experiments were used in conjunction with other geochemical and hydraulic characterization to design the field-scale injection experiment and predict barrier longevity. For example, the sediment reduction rate controls the amount of time required for the dithionite solution to fully react with sediments. Sediment oxidation experiments were additionally conducted to determine the oxidation rate and provide a separate measure of the mass of reduced iron. Laboratory experiments that were used to meet these objectives included: (1) sediment reduction in batch (static) systems, (2) sediment reduction in 1-D columns, and (3) sediment oxidation in 1-D columns. Multiple reaction modeling was conducted to quantify the reactant masses and reaction rates.« less

Method and apparatus for in-situ drying investigation and optimization of slurry drying methodology

DOEpatents

Armstrong, Beth L.; Daniel, Claus; Howe, Jane Y.; Kiggans, Jr, James O.; Sabau, Adrian S.; Wood, III, David L.; Kalnaus, Sergiy

2016-05-10

A method of drying casted slurries that includes calculating drying conditions from an experimental model for a cast slurry and forming a cast film. An infrared heating probe is positioned on one side of the casted slurry and a thermal probe is positioned on an opposing side of the casted slurry. The infrared heating probe may control the temperature of the casted slurry during drying. The casted slurry may be observed with an optical microscope, while applying the drying conditions from the experimental model. Observing the casted slurry includes detecting the incidence of micro-structural changes in the casted slurry during drying to determine if the drying conditions from the experimental model are optimal.

The fate of nitrogen is linked to iron(II) availability in a freshwater lake sediment

NASA Astrophysics Data System (ADS)

Robertson, Elizabeth K.; Thamdrup, Bo

2017-05-01

The fate of nitrogen in natural environments is controlled by anaerobic nitrate-reducing processes by which nitrogen is removed as N2 or retained as NH4+. These processes can potentially be driven by oxidation of reduced inorganic compounds at oxic-anoxic interfaces. Several studies have investigated the use of Fe2+ as an electron donor in nitrate reduction in bacterial cultures, however current information on this process in the environment is sparse. We aimed to determine whether nitrate-reducing processes in the freshwater Lake Almind (Silkeborg, Denmark) were linked to Fe2+ oxidation. Anaerobic sediment slurries were supplemented with 15N-substrates and electron donors (Fe2+ and/or acetate) to characterize nitrate-reducing processes under environmentally relevant substrate concentrations and at higher concentrations traditionally used in microbial enrichment studies. Dissimilatory nitrate reduction to ammonium, DNRA, was stimulated by Fe2+ addition in 7 of 10 slurry experiments and in some cases, denitrification was concomitantly reduced. The determined kinetic parameters (Vmax and Km) for Fe2+-driven DNRA were 4.7 μmol N L-1 d-1 and 33.8 μmol Fe2+ L-1, respectively and reaction stoichiometry for Fe2+:NH4+ (8.2:1) was consistent with that of predicted stoichiometry (8:1). Conversely, under enrichment conditions, denitrification was greatly increased while DNRA rates remained unchanged. Increased Fe2+ concentrations may be exploited by DNRA organisms and have an inhibitory effect on denitrification, thus Fe2+ may play a role in regulating N transformations in Lake Almind. Furthermore, we suggest enrichment conditions may promote the adaptation or change of microbial communities to optimally utilize the available high substrate concentrations; misrepresenting metabolisms occurring in situ.

Method of making a functionally graded material

DOEpatents

Lauf, Robert J.; Menchhofer, Paul A.; Walls, Claudia A.

2001-01-01

A gelcasting method of making an internally graded article includes the steps of: preparing at least two slurries, each of the slurries including a different gelcastable powder suspended in a gelcasting solution, the slurries characterized by having comparable shrinkage upon drying and sintering thereof; casting the slurries into a mold having a selected shape, wherein relative proportions of the slurries is varied in at least one direction within the selected shape; gelling the slurries to form a solid gel while preserving the variation in relative proportions of the slurries; drying the gel to form a dried green body; and sintering the dry green body to form a solid object, at least one property thereof varying because of the variation in relative proportions of the starting slurries. A gelcasting method of making an internally graded article alternatively includes the steps of: preparing a slurry including a least two different phases suspended in a gelcasting solution, the phases characterized by having different settling characteristics; casting the slurry into a mold having a selected shape; allowing the slurry to stand for a sufficient period of time to permit desired gravitational fractionation in order to achieve a vertical compositional gradient in the molded slurry; gelling the slurry to form a solid gel while preserving the vertical compositional gradient in the molded slurry; drying the gel to form a dried green body; and sintering the dry green body to form a solid object, at least one property thereof varying along the vertical direction because of the compositional gradient in the molded slurry.

Remedial site evaluation report for the waste area grouping 10 wells associated with the new hydrofracture facility at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Volume 1: Evaluation, interpretation, and data summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-08-01

The Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, is operated for the U.S. Department of Energy (DOE) by Lockheed Martin Energy System (Energy Systems). ORNL has pioneered waste disposal technologies since World War II as part of its DOE mission. In the late 1950s, at the request of the National Academy of Sciences, efforts were made to develop a permanent disposal alternative to the surface and tanks at ORNL. One such technology, the hydrofracture process, involved inducing fractures in a geologic host formation (a low-permeability shale) at depths of up to 1100 ft and injecting a radioactive groutmore » slurry containing low-level liquid or tank sludge waste, cement, and other additives at an injection pressure of 2000 to 8500 psi. The objective of the effort was to develop a grout dig could be injected as a slurry and would solidify after injection, thereby entombing the radioisotopes contained in the low-level liquid or tank sludge waste. Four sites at ORNL were used: two experimental (HF-1 and HF-2); one developmental, later converted to batch process [Old Hydrofracture Facility (BF-3)]; and one production facility [New Hydrofracture Facility (BF-4)]. This document provides the environmental, restoration program with information about the the results of an evaluation of WAG 10 wells associated with the New Hydrofracture Facility at ORNL.« less

Laboratory study on metal attenuation capacity of fine grained soil near ash pond site.

PubMed

Ghosh, Sudipta; Mukherjee, Somnath; Sarkar, Sujoy; Kumar, Sunil

2008-10-01

Waste settling tanks of earthen containment nature are common in India for disposal of solid waste in slurry form. For a large pond system, e.g. ash slurry disposal tank of coal base thermal power plant, leachate generation and its migration pose a serious problem. A natural attenuation of controlling the migratory leachate is to use locally available clay material as lining system due to the adsorption properties of soil for reducing some metallic ions. The present investigation was carried out to explore the Ni2+ and Cr6+ removal capacity of surrounding soil of the ash pond site of Super Thermal Power Plant in West Bengal, India through some laboratory scale and field studies. The soil and water samples collected from the site showed the existence of Ni2+ and Cr6+ in excess to permissible limit. A two-dimensional adsorption behaviour of these pollutants through soil was assessed. The results showed that more than 80% of nickel and 72% of chromium were found to be sorbed by the soil corresponding to initial concentrations of two ions, i.e. 1.366 mg/L and 0.76 mg/L respectively. The batch adsorption data are tested Langmuir and Freundlich isotherm models and found reasonably fit. Breakthrough adsorption study uptake also showed a good adsorption capacity of the soil. The experimental results found to fit well with the existing two dimensional (2D) mathematical models as proposed by Fetter (1999).

Sustainable nutrients recovery and recycling by optimizing the chemical addition sequence for struvite precipitation from raw swine slurries.

PubMed

Taddeo, Raffaele; Kolppo, Kari; Lepistö, Raghida

2016-09-15

Livestock farming contributes heavily to nitrogen (N) and phosphorus (P) flows into the environment, a major cause of eutrophication of coastal and freshwater systems. Furthermore, the growing demand for N-P fertilizers is increasing the emission of anthropogenic reactive N into the atmosphere and the depletion of the current P reserves. Therefore, it is essential to minimize the anthropogenic impact on the environment and recycle the wasted N-P for agricultural reuse. This study focused on enhancing struvite (MgNH4PO4*6H2O) precipitation from raw swine slurries in batch and laboratory-scale reactors. Different chemical addition sequences were evaluated, and the best removal efficiency (E%) was obtained when the chemicals were mixed before the precipitation process. Struvite was detected at a pH as low as 6 (E%N-P∼50%), and high E%N-P was found at pH 7-9.5 (80-95%). Furthermore, air stripping was used in place of NaOH to adjust pH, returning the same efficiency as if only alkali had been used. XRD and FE-SEM analysis of the precipitate showed that the recovered struvite was of high purity with orthorhombic crystalline structure and only trace amounts of impurities from matrix organics, co-precipitation products (CaO and amorphous calcium-phosphates), and residuals of added chemicals (MgO). Copyright © 2016 Elsevier Ltd. All rights reserved.

Temporal variation of aerobic methane oxidation over a tidal cycle in a wetland of northern Taiwan.

NASA Astrophysics Data System (ADS)

Lee, T. Y.; Wang, P. L.; Lin, L. H.

2017-12-01

Aerobic methanotrophy plays an important role in controlling methane emitted from wetlands. However, the activity of aerobic methanotrophy regulated by temporal fluctuation of oxygen and methane supply in tidal wetlands is not well known. This study aims to examine the dynamics of methane fluxes and potential aerobic methane consumption rates in a tidal wetland of northern Taiwan, where the variation of environmental characteristics, such as sulfate and methane concentration in pore water has been demonstrated during a tidal cycle. Two field campaigns were carried out in December of 2016 and March of 2017. Fluxes of methane emission, methane concentrations in surface sediments and oxygen profiles were measured at different tidal phases. Besides, batch incubations were conducted on surface sediments in order to quantify potential microbial methane consumption rates and to derive the kinetic parameters for aerobic methanotrophy. Our results demonstrated temporal changes of the surface methane concentration and the methane emission flux during a tidal cycle, while the oxygen flux into the sediment was kept at a similar magnitude. The methane flux was low when the surface was exposed for both shortest and longest periods of time. The potential aerobic methane oxidation rate was high for sample collected from the surface sediments exposed the longest. No correlation could be found between the potential aerobic methane oxidation rate and either the oxygen downward flux or methane emission flux. The decoupled relationships between these observed rates and fluxes suggest that, rather than aerobic methanotrophy, heterotrophic respirations exert a profound control on oxygen flux, and the methane emission is not only been affected by methane consumption but also methane production at depths. The maximum potential rate and the half saturation concentration determined from the batch incubations were high for the surface sediments collected in low tide, suggesting that aerobic methanotrophy could be modulated to reach peak activity once the influence of saline water is reduced to a low level.

Vertical migration of fine-grained sediments from interior to surface of seabed driven by seepage flows-`sub-bottom sediment pump action'

NASA Astrophysics Data System (ADS)

Zhang, Shaotong; Jia, Yonggang; Wen, Mingzheng; Wang, Zhenhao; Zhang, Yaqi; Zhu, Chaoqi; Li, Bowen; Liu, Xiaolei

2017-02-01

A scientific hypothesis is proposed and preliminarily verified in this paper: under the driving of seepage flows, there might be a vertical migration of fine-grained soil particles from interior to surface of seabed, which is defined as `sub-bottom sediment pump action' in this paper. Field experiments were performed twice on the intertidal flat of the Yellow River delta to study this process via both trapping the pumped materials and recording the pore pressures in the substrate. Experimental results are quite interesting as we did observe yellow slurry which is mainly composed of fine-grained soil particles appearing on the seabed surface; seepage gradients were also detected in the intertidal flat, under the action of tides and small wind waves. Preliminary conclusions are that `sediment pump' occurs when seepage force exceeds a certain threshold: firstly, it is big enough to disconnect the soil particles from the soil skeleton; secondly, the degree of seabed fluidization or bioturbation is big enough to provide preferred paths for the detached materials to migrate upwards. Then they would be firstly pumped from interior to the surface of seabed and then easily re-suspended into overlying water column. Influential factors of `sediment pump' are determined as hydrodynamics (wave energy), degree of consolidation, index of bioturbation (permeability) and content of fine-grained materials (sedimentary age). This new perspective of `sediment pump' may provide some implications for the mechanism interpretation of several unclear geological phenomena in the Yellow River delta area.

Measurement of nitrous oxide reductase activity in aquatic sediments

USGS Publications Warehouse

Miller, L.G.; Oremland, R.S.; Paulsen, S.

1986-01-01

Denitrification in aquatic sediments was measured by an N2O reductase assay. Sediments consumed small added quantities of N2O over short periods (a few hours). In experiments with sediment slurries, N2O reductase activity was inhibited by O2, C2H2, heat treatment, and by high levels of nitrate (1 mM) or sulfide (10 mM). However, ambient levels of nitrate (<100 μM) did not influence activity, and moderate levels (about 150 μM) induced only a short lag before reductase activity began. Moderate levels of sulfide (<1 mM) had no effect on N2O reductase activity. Nitrous oxide reductase displayed Michaelis-Menten kinetics in sediments from freshwater (Km = 2.17 μM), estuarine (Km = 14.5 μM), and alkaline-saline (Km = 501 μM) environments. An in situ assay was devised in which a solution of N2O was injected into sealed glass cores containing intact sediment. Two estimates of net rates of denitrification in San Francisco Bay under approximated in situ conditions were 0.009 and 0.041 mmol of N2O per m2 per h. Addition of chlorate to inhibit denitrification in these intact-core experiments (to estimate gross rates of N2O consumption) resulted in approximately a 14% upward revision of estimates of net rates. These results were comparable to an in situ estimate of 0.022 mmol of N2O per m2 per h made with the acetylene block assay.

High performance 1.2 Ah Si-alloy/Graphite|LiNi0.5Mn0.3Co0.2O2 prototype Li-ion battery

NASA Astrophysics Data System (ADS)

Marinaro, Mario; Yoon, Dong-hwan; Gabrielli, Giulio; Stegmaier, Petra; Figgemeier, Egbert; Spurk, Paul C.; Nelis, Daniël; Schmidt, Gregory; Chauveau, Jerome; Axmann, Peter; Wohlfahrt-Mehrens, Margret

2017-07-01

The study reports on realization and electrochemical testing of prototype Si-alloy/Graphite|LiNi0.5Mn0.3Co0.2O2 batteries. Water soluble polyacrylic acid (PAA), used as the only binder at the anode side, demonstrates excellent dispersant and binding properties. Sedimentation tests and rheological measurements show remarkable stability and mostly a thinning behavior of the non-Newtonian type of slurry. The cathode is processed in N-Methylpyrrolidone based slurry using polyvinylidene fluoride (PVDF) as the binding agent. The electronic conductivities of the manufactured Si-alloy/Graphite and LiNi0.5Mn0.3Co0.2O2 electrodes are evaluated. Furthermore, the cathode and anode electrochemical behavior is initially studied in half-cells, and subsequently in full Li-ion stacked prototype soft pouch-cells (1.22 Ah). It is demonstrated that the manufactured prototype cells can sustain about 290 charge/discharge galvanostatic cycles before the retained capacity drops below 80%. Cell aging is monitored using Electrochemical Impedance Spectroscopy (EIS), whereas post-mortem SEM analysis of electrodes cross-section is used to shed light on the causes of performance degradation of the cells.

Methylmercury oxidative degradation potentials in contaminated and pristine sediments of the Carson River, Nevada

USGS Publications Warehouse

Oremland, R.S.; Miller, L.G.; Dowdle, P.; Connell, T.; Barkay, T.

1995-01-01

Sediments from mercury-contaminated and uncontaminated reaches of the Carson River, Nevada, were assayed for sulfate reduction, methanogenesis, denitrification, and monomethylmercury (MeHg) degradation. Demethylation of [14C]MeHg was detected at all sites as indicated by the formation of 14CO2 and 14CH4. Oxidative demethylation was indicated by the formation of 14CO2 and was present at significant levels in all samples. Oxidized/reduced demethylation product ratios (i.e., 14CO2/14CH4 ratios) generally ranged from 4.0 in surface layers to as low as 0.5 at depth. Production of 14CO2 was most pronounced at sediment surfaces which were zones of active denitrification and sulfate reduction but was also significant within zones of methanogenesis. In a core taken from an uncontaminated site having a high proportion of oxidized, coarse-grain sediments, sulfate reduction and methanogenic activity levels were very low and 14CO2 accounted for 98% of the product formed from [14C]MeHg. There was no apparent relationship between the degree of mercury contamination of the sediments and the occurrence of oxidative demethylation. However, sediments from Fort Churchill, the most contaminated site, were most active in terms of demethylation potentials. Inhibition of sulfate reduction with molybdate resulted in significantly depressed oxidized/reduced demethylation product ratios, but overall demethylation rates of inhibited and uninhibited samples were comparable. Addition of sulfate to sediment slurries stimulated production of 14CO2 from [14C]MeHg, while 2-bromoethanesulfonic acid blocked production of 14CH4. These results reveal the importance of sulfate-reducing and methanogenic bacteria in oxidative demethylation of MeHg in anoxic environments.

Combined on-board hydride slurry storage and reactor system and process for hydrogen-powered vehicles and devices

DOEpatents

Brooks, Kriston P; Holladay, Jamelyn D; Simmons, Kevin L; Herling, Darrell R

2014-11-18

An on-board hydride storage system and process are described. The system includes a slurry storage system that includes a slurry reactor and a variable concentration slurry. In one preferred configuration, the storage system stores a slurry containing a hydride storage material in a carrier fluid at a first concentration of hydride solids. The slurry reactor receives the slurry containing a second concentration of the hydride storage material and releases hydrogen as a fuel to hydrogen-power devices and vehicles.

Silver doped catalysts for treatment of exhaust

DOEpatents

Park, Paul Worn [Peoria, IL; Boyer, Carrie L [Shiloh, IL

2006-12-26

A method of making an exhaust treatment catalyst includes dispersing a metal-based material in a first solvent to form a first slurry and allowing polymerization of the first slurry to occur. Polymerization of the first slurry may be quenched and the first slurry may be allowed to harden into a solid. This solid may be redistributed in a second solvent to form a second slurry. The second slurry may be loaded with a silver-based material, and a silver-loaded powder may be formed from the second slurry.

An investigation on the rheological behavior of metallic semi-solid slurries of Al-6.5 pct Si and semi-solid composite slurries of SiC particulates in an Al-6.5 pct Si alloy matrix

NASA Technical Reports Server (NTRS)

Moon, H.-K.; Ito, Y.; Cornie, J. A.; Flemings, M. C.

1993-01-01

The rheology of SiC particulate/Al-6.5 pct Si composite slurries was explored. The rheological behavior of the composite slurries shows both thixotropic and pseudoplastic behaviors. Isostructural experiments on the composite slurries revealed a Newtonian behavior beyond a high shear rate limit. The rheology of fully molten composite slurries over the low to high shear rate range indicates the existence of a low shear rate Newtonian region, an intermediate pseudoplastic region and a high shear rate Newtonian region. The isostructural studies indicate that the viscosity of a composite slurry depends upon the shearing history of a given volume of material. An unexpected shear thinning was noted for SiC particulate + alpha slurries as compared to semi-solid metallic slurries at the same fraction solid. The implications of these findings for the processing of slurries into cast components is discussed.

Ammonia volatilization from farm tanks containing anaerobically digested animal slurry

NASA Astrophysics Data System (ADS)

Sommer, S. G.

Ammonia (NH 3) volatilization from three full-scale tanks containing anaerobically digested animal slurry from one biogas plant was determined with a meteorological mass balance technique. No surface crust developed on the slurry. This provided an ideal system for analysing loss patterns from slurries without cover and to study the effect of a cover of straw and air-filled clay granules. Ammonia volatilization from uncovered slurry ranged from zero at subzero temperatures to 30 g N m -2 d -1 during summer. The high volatilization rate was attributed to a lack of surface cover, high slurry pH and high TAN (NH 3 + NH 4+) concentration. Ammonia volatilization from the covered slurry was insignificant. From the uncovered slurry the annual loss of NH3 was 3.3 kg N m -2 There was a significant effect of incident global radiation (ICR), air temperature at 20 cm (T_20) and rain on NH3 volatilization from the uncovered slurry. The straw covered slurry was significantly affected by T_20.

Short-chain alkane cycling in deep Gulf of Mexico cold-seep sediments

NASA Astrophysics Data System (ADS)

Sibert, R.; Joye, S. B.; Hunter, K.

2015-12-01

Mixtures of light hydrocarbon gases are common in deep Gulf of Mexico cold-seep sediments, and are typically dissolved in pore fluids, adsorbed to sediment particles, trapped in methane ice, or as free gas. The dominant component in these natural gas mixtures is usually methane (>80% C1), but ethane (C2) and propane (C3) are nearly always present in trace amounts (<1% total). The processes that control the concentration and isotopic signature of these gases in sediments are well explained for methane, but the controls for C2/C3 cycling are still a relative mystery. Methane production proceeds in deep anoxic sediments by either 1) thermocatalytic cracking of fossil organic matter, or 2) as a direct product of microbial metabolism, i.e. methanogenesis. In surface sediments, it appears that both microbial consumption and chemical deposition of methane (i.e. as methane clathrate) ensures that >95% of the methane produced at depth never reaches the water column. Production of C1 and C2 in deep-sea sediments has been historically attributed only to thermocatalytic processes, though limited data suggests production of C2/C3 compounds through the activity of archaea at depth. Furthermore, carbon isotopic data on ethane and propane from deep cores of Gulf of Mexico sediments suggest alkanogenesis at >3 m depth in the sediment column and alkane oxidation in uppermost oxidant-rich sediments. Additional studies have also isolated microorganisms capable of oxidizing ethane and propane in the laboratory, but field studies of microbial-driven dynamics of C2/C3 gases in cold-seep sediments are rare. Here, we present the results of a series of incubation experiments using sediment slurries culled from surface sediments from one of the most prolific natural oil and gas seeps in the Gulf of Mexico. Rates of alkane oxidation were measured under a variety of conditions to assess the surface-driven microbial controls on C2/C3 cycling in cold-seep environments. Such microbial processes are important in terms of the possible 'oxidative overprinting' of alkane isotopic signatures produced at depth, possibly obscuring typical microbial isotopic signals.

Effect of Oxalic Acid Treatment on Sediment Arsenic Concentrations and Lability under Reducing Conditions

PubMed Central

Sun, Jing; Bostick, Benjamin C.; Mailloux, Brian J.; Ross, James M.; Chillrud, Steven N.

2016-01-01

Oxalic acid enhances arsenic (As) mobilization by dissolving As host minerals and competing for sorption sites. Oxalic acid amendments thus could potentially improve the efficiency of widely used pump-and-treat (P&T) remediation. This study investigates the effectiveness of oxalic acid on As mobilization from contaminated sediments with different As input sources and redox conditions, and examines whether residual sediment As after oxalic acid treatment can still be reductively mobilized. Batch extraction, column, and microcosm experiments were performed in the laboratory using sediments from the Dover Municipal Landfill and the Vineland Chemical Company Superfund sites. Oxalic acid mobilized As from both Dover and Vineland sediments, although the efficiency rates were different. The residual As in both Dover and Vineland sediments after oxalic acid treatment was less vulnerable to microbial reduction than before the treatment. Oxalic acid could thus improve the efficiency of P&T. X-ray absorption spectroscopy analysis indicated that the Vineland sediment samples still contained reactive Fe(III) minerals after oxalic acid treatment, and thus released more As into solution under reducing conditions than the Dover samples. Therefore, the efficacy of P&T must consider sediment Fe mineralogy when evaluating its overall potential for remediating groundwater As. PMID:26970042

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mouser, Paula J.; N'Guessan, A. Lucie; Qafoku, Nikolla

The capacity for subsurface sediments to sequester metal contaminants, such as uranium (U), and retain them after bioremediation efforts are completed is critical to site stewardship. Sediments enriched in natural organic matter are capable of sequestering significant quantities of U, but may also serve as sources to the aquifer, contributing to plume persistence. Two types of sediments were compared to better understand the mechanisms contributing to the sequestration and release of U in the presence of organic matter. Artificially bioreduced sediments were retrieved from a field experimental plot previously stimulated with acetate while naturally bioreduced sediments were collected from amore » location enriched in organic matter but never subject to acetate amendment. Batch incubations demonstrated that the artificially bioreduced sediments were primed to rapidly remove uranium from the groundwater whereas naturally bioreduced sediments initially released a sizeable portion of sediment U before U(VI)-removal commenced. Column experiments confirmed that U release persisted for 65 pore volumes in naturally bioreduced sediments, demonstrating the sink-source behavior of this sediment. Acetate addition to artificially bioreduced sediments shifted the microbial community from one dominated by sulfate-reducing bacteria within Desulfobacteraceae to the iron-reducing family Geobacteraceae and Firmicutes during U(VI) reduction. In contrast, initial Geobacteraceae communities innaturally reduced sediments were replaced by clone sequences with similarity to opportunistic Pseudomonas spp. during U release, while U(VI) removal occurred concurrent with enrichment of Firmicutes. These investigations stress the importance of characterizing zones with heterogeneous carbon pools at U contaminated sites prior to the determination of a remedial strategy.« less

Manifold Coal-Slurry Transport System

NASA Technical Reports Server (NTRS)

Liddle, S. G.; Estus, J. M.; Lavin, M. L.

1986-01-01

Feeding several slurry pipes into main pipeline reduces congestion in coal mines. System based on manifold concept: feeder pipelines from each working entry joined to main pipeline that carries coal slurry out of panel and onto surface. Manifold concept makes coal-slurry haulage much simpler than existing slurry systems.

Reduction of elemental selenium to selenide: Experiments with anoxic sediments and bacteria that respire Se-oxyanions

USGS Publications Warehouse

Herbel, M.J.; Blum, J.S.; Oremland, R.S.; Borglin, S.E.

2003-01-01

A selenite-respiring bacterium, Bacillus selenitireducens, produced significant levels of Se(-II) (as aqueous HSe-) when supplied with Se(O). B. selenitireducens was also able to reduce selenite [Se(IV)] through Se(O) to Se(-II). Reduction of Se(O) by B.selenitireducens was more rapid in cells grown on colloidal sulfur [S(O)] or Se(IV) as their electron acceptor than for cell lines grown on fumarate. In contrast, three cultures of selenate-respiring bacteria, Sulfurospirillum barnesii, B. arsenicoselenatis, and Selenihalanaerobacter shriftii either were unable to reduce Se(O) to Se(-II) or had only a very limited capacity to achieve this reduction. Biological reduction of Se(O) to Se(-II) was observed during incubation of estuarine sediment slurries, while no such activity was noted in formalin-killed controls. The majority of the Se(-II) produced was found in the sediments as a solid precipitate of FeSe, rather than in solution as HSe-. These results demonstrate that certain anaerobic bacteria have the capacity to reduce Se(O) to Se(-II), providing a possible biological explanation for the occurrence of the selenide species in some sedimentary rocks.

Hydrothermal pretreatment of palm oil empty fruit bunch

NASA Astrophysics Data System (ADS)

Simanungkalit, Sabar Pangihutan; Mansur, Dieni; Nurhakim, Boby; Agustin, Astrid; Rinaldi, Nino; Muryanto, Fitriady, Muhammad Ariffudin

2017-01-01

Hydrothermal pretreatment methods in 2nd generation bioethanol production more profitable to be developed, since the conventional pretreatment, by using acids or alkalis, is associated with the serious economic and environmental constraints. The current studies investigate hydrothermal pretreatment of palm oil empty fruit bunch (EFB) in a batch tube reactor system with temperature and time range from 160 to 240 C and 15 to 30 min, respectively. The EFB were grinded and separated into 3 different particles sizes i.e. 10 mesh, 18 mesh and 40 mesh, prior to hydrothermal pretreatment. Solid yield and pH of the treated EFB slurries changed over treatment severities. The chemical composition of EFB was greatly affected by the hydrothermal pretreatment especially hemicellulose which decreased at higher severity factor as determined by HPLC. Both partial removal of hemicellulose and migration of lignin during hydrothermal pretreatment caused negatively affect for enzymatic hydrolysis. This studies provided important factors for maximizing hydrothermal pretreatment of EFB.

Slurry atomizer for a coal-feeder and dryer used to provide coal at gasifier pressure

DOEpatents

Loth, John L.; Smith, William C.; Friggens, Gary R.

1982-01-01

The present invention is directed to a coal-water slurry atomizer for use a high-pressure dryer employed in a pumping system utilized to feed coal into a pressurized coal gasifier. The slurry atomizer is provided with a venturi, constant area slurry injection conduit, and a plurality of tangentially disposed steam injection ports. Superheated steam is injected into the atomizer through these ports to provide a vortical flow of the steam, which, in turn, shears slurry emerging from the slurry injection conduit. The droplets of slurry are rapidly dispersed in the dryer through the venturi where the water is vaporized from the slurry by the steam prior to deleterious heating of the coal.

Rapid reservoir erosion, hyperconcentrated flow, and downstream deposition triggered by breaching of 38 m tall Condit Dam, White Salmon River, Washington

USGS Publications Warehouse

Wilcox, Andrew C.; O'Connor, James E.; Major, Jon J.

2014-01-01

Condit Dam on the White Salmon River, Washington, a 38 m high dam impounding a large volume (1.8 million m3) of fine-grained sediment (60% sand, 35% silt and clay, and 5% gravel), was rapidly breached in October 2011. This unique dam decommissioning produced dramatic upstream and downstream geomorphic responses in the hours and weeks following breaching. Blasting a 5 m wide hole into the base of the dam resulted in rapid reservoir drawdown, abruptly releasing ~1.6 million m3 of reservoir water, exposing reservoir sediment to erosion, and triggering mass failures of the thickly accumulated reservoir sediment. Within 90 min of breaching, the reservoir's water and ~10% of its sediment had evacuated. At a gauging station 2.3 km downstream, flow increased briefly by 400 m3 s−1during passage of the initial pulse of released reservoir water, followed by a highly concentrated flow phase—up to 32% sediment by volume—as landslide-generated slurries from the reservoir moved downstream. This hyperconcentrated flow, analogous to those following volcanic eruptions or large landslides, draped the downstream river with predominantly fine sand. During the ensuing weeks, suspended-sediment concentration declined and sand and gravel bed load derived from continued reservoir erosion aggraded the channel by >1 m at the gauging station, after which the river incised back to near its initial elevation at this site. Within 15 weeks after breaching, over 1 million m3 of suspended load is estimated to have passed the gauging station, consistent with estimates that >60% of the reservoir's sediment had eroded. This dam removal highlights the influence of interactions among reservoir erosion processes, sediment composition, and style of decommissioning on rate of reservoir erosion and consequent downstream behavior of released sediment.

The dark side of the hyporheic zone: Depth profiles of nitrogen and its processing in stream sediments

USGS Publications Warehouse

Stelzer, R.S.; Bartsch, L.A.; Richardson, W.B.; Strauss, E.A.

2011-01-01

1.Although it is well known that sediments can be hot spots for nitrogen transformation in streams, many previous studies have confined measurements of denitrification and nitrate retention to shallow sediments (<5cm deep). We determined the extent of nitrate processing in deeper sediments of a sand plains stream (Emmons Creek) by measuring denitrification in core sections to a depth of 25cm and by assessing vertical nitrate profiles, with peepers and piezometers, to a depth of 70cm. 2.Denitrification rates of sediment slurries based on acetylene block were higher in shallower core sections. However, core sections deeper than 5cm accounted for 68% of the mean depth-integrated denitrification rate. 3.Vertical hydraulic gradient and vertical profiles of pore water chloride concentration suggested that deep ground water upwelled through shallow sediments before discharging to the stream channel. The results of a two-source mixing model based on chloride concentrations suggested that the hyporheic zone was very shallow (<5cm) in Emmons Creek. 4.Vertical profiles showed that nitrate concentration in shallow ground water was about 10-60% of the nitrate concentration of deep ground water. The mean nitrate concentrations of deep and shallow ground water were 2.17 and 0.73mgNO3-NL-1, respectively. 5.Deep ground water tended to be oxic (6.9mgO2L-1) but approached anoxia (0.8mgO2L-1) after passing through shallow, organic carbon-rich sediments, which suggests that the decline in the nitrate concentrations of upwelling ground water was because of denitrification. 6.Collectively, our results suggest that there is substantial nitrate removal occurring in deep sediments, below the hyporheic zone, in Emmons Creek. Our findings suggest that not accounting for nitrate removal in deep sediments could lead to underestimates of nitrogen processing in streams and catchments. ?? 2011 Blackwell Publishing Ltd.

Combustion characterization of carbonized RDF, Joint Venture Task No. 7. Topical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

1995-04-30

The overall objective of this research program was to demonstrate EnerTech's and the Energy & Environmental Research Center's (EERC) process of slurry carbonization for producing homogeneous, pumpable titels from refuse-derived fuel (RDF) with continuous pilot plant facilities, and to characterize flue gas and ash emissions from combustion of the carbonizd RDF slurry fuel. Please note that "Wet Thermal Oxidation" is EnerTech's trademark mme for combustion of the carbonized RDF slurry fuel. Carbonized RDF slurry fuels were produced with the EERC'S 7.5-tpd (wet basis) pilot plant facility. A hose diaphragm pump pressurized a 7- lo-wt% feed RDF slurry, with a viscositymore » of 500 cP, to approximately 2500 psig. The pressurized RDF slurry was heated by indirect heat exchangers to between 5850 -626°F, and its temperature and pressure was maintained in a downflow reactor. The carbonized slurry was flashed, concentrated in a filter press, and ground in an attritor. During operation of the pilot plant, samples of the feed RDF slurry, carbonization gas, condensate, carbonized solids, and filtrate were taken and analyzed. Pilot-scale slurry carbonization experiments with RDF produced a homogeneous pumpable slurry fuel with a higher heating value (HHV) of 3,000-6,600 Btu/lb (as-received basis), at a viscosity of 500 CP at 100 Hz decreasing, and ambient temperature. Greater-heating-value slurry fuels were produced at higher slurry carbonization temperatures. During slurry carbonization, polyvinyl chloride (PVC) plastics in the feed RDF also decompose to form hydrochloric acid and salts. Pilot-scale slurty carbonization experiments extracted 82-94% of the feed RDF chlorine content as chloride salts. Higher carbonization temperatures and higher alkali additions to the feed slurry produced a higher chlorine extraction.« less

Method for inducing hypothermia

DOEpatents

Becker, Lance B.; Hoek, Terry Vanden; Kasza, Kenneth E.

2003-04-15

Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.

Method for inducing hypothermia

DOEpatents

Becker, Lance B [Chicago, IL; Hoek, Terry Vanden [Chicago, IL; Kasza, Kenneth E [Palos Park, IL

2008-09-09

Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.

Method for inducing hypothermia

DOEpatents

Becker, Lance B.; Hoek, Terry Vanden; Kasza, Kenneth E.

2005-11-08

Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.

The Distribution and Abundance of Mercury Methylating Microorganisms in Mid-Atlantic Wetlands

NASA Astrophysics Data System (ADS)

Santillan, E. F. U.; Gilmour, C. C.; Schwartz, G.; Christensen, G. A.; King, A. J.; Elias, D. A.

2015-12-01

The discovery of the genes responsible for microbial methylmercury production, hgcAB, has led to the identification of novel Hg methylators with diverse metabolisms including Fe and SO42- reducing bacteria, syntrophs, and methanogens. We recently developed DNA probes for hgcA in each group of methylators: Deltaproteobacteria, Firmicutes, and Archaea [Christensen, 2015]. In this study, we use the probes to determine quantity and distribution of hgcA+ organisms in mid-Atlantic marshes and sediments, and in Hg-contaminated wetland soils. We also analyze hgcA distribution over a 28-day soil slurry experiment designed to evaluate the impact of activated carbon on Hg methylation and demethylation [Gilmour, 2015]. Initial soils show Deltaproteobacteria comprise most hgcA+ organisms. Methanogens encompass >45% of the remaining methylators. The addition of SO42- to induce SO42- reducing conditions in slurries caused the number of hgcA+ Deltaproteobacteria to increase and the number of hgcA+ methanogens to decrease to >32%. In soils and slurries, Firmicutes were below detection, suggesting our Firmicute primers are either unrepresentative in natural samples, or that hgcA+ Firmicutes are rare. This observation is interesting as Firmicutes include organisms with divergent metabolisms, and their role in environmental methylation is still unknown. Slurries also show no correlation between hgcA abundance and Hg concentrations. We now plan to explore how hgcA abundance relates to Hg-methylation and electron acceptor availability. Our results offer initial insights into the natural distribution of hgcA, supporting the idea that the distribution of different methylators is related to electron acceptors and redox chemistry. Christensen, G., Wymore, AM, King, A, Pdar, M, Hurt Jur, RA, Santillan, EFU, Gilmour, CC, Brandt, CC, Brown, SD, Palumbo, AV, Elias, DA (2015), A Study of Mercury Methylation Genetics: Qualitative and Quantitative Analysis of hgcAB in Pure Culture, paper presented at American Geophysical Union, San Francisco, CA, USA. Gilmour, C., Ghosh, U, Santillan, EFU, Soren, AB, Bell, T, Butera, D, McBurney, A (2015), Impacts of Activated Carbon Amendment on Hg Methylation, Demethylation and Microbial Activity in Marsh Soils, paper presented at American Geophysical Union, San Francisco, CA, USA.

Salinity effects on the dynamics and patterns of desiccation cracks

NASA Astrophysics Data System (ADS)

Shokri, N.; Zhou, P.

2012-12-01

Cracking arising from desiccation is a ubiquitous phenomenon encountered in various industrial and geo-environmental applications including drying of clayey soil, cement, ceramics, gels, and many more colloidal suspensions. Presence of cracks in muddy sediments modifies the characteristics of the medium such as pore structure, porosity, and permeability which in turn influence various flow and transport processes. Thus it remains a topic of great interest in many disciplines to describe the dynamics of desiccation cracking under various boundary conditions. To this end, we conducted a comprehensive study to investigate effects of NaCl concentrations on cracking dynamics and patterns during desiccation of Bentonite. Mixtures of Bentonite and NaCl solutions were prepared with NaCl concentration varying from 2 to 10 percent in 0.5 percent increment (totally 17 configurations). The slurry was placed in a Petri dish mounted on a digital balance to record the evaporation dynamics. The atmospheric conditions were kept constant using an environmental chamber. An automatic camera was used to record the dynamics of macro-cracks (mm scale) at the surface of desiccating clay each minute. The obtained results illustrate the significant effects of salt concentration on the initiation, propagation, morphology and general dynamics of macro-cracks. We found that higher salt concentrations results in larger macro cracks' lengths attributed to the effects of NaCl on compressing the electric double layer of particles at increasing electrolyte concentrations which reduce considerably the repulsive forces among the particles and causing instability of the slurry and flocculation of the colloidal particles. Rheological measurements by means of a stress controlled rheometer revealed that the yield stress of the slurry decreases as NaCl concentration increases which may indicate aggregation of larger units in the slurry as a result of flocculation causing larger cracks' lengths due to drying. At the end of each round of the experiment, a detailed visualization was conducted using Scanning Electron Microscopy to investigate the patterns and morphology of cracks at micro-scale as influenced by the salt concentration. Our results provide new insights and finding about the effects of salt concentrations on desiccation cracks at different scales ranging from a few mm to few microns.

Conductivity and electrochemical performance of LiFePO4 slurry in the lithium slurry battery

NASA Astrophysics Data System (ADS)

Feng, Caimei; Chen, Yongchong; Liu, Dandan; Zhang, Ping

2017-06-01

Lithium slurry battery is a new type of energy storage technique which uses the slurry of solid active materials, conductive additions and liquid electrolyte as the electrode. The proportion of conductive addition and the active material has significant influence on the conductivity and electrochemical performance of the slurry electrode. In the present work, slurries with different volume ratios of LiFePO4 (LFP) and Ketjenblack (KB) were investigated by the electrochemical workstation and charge-discharge testing system (vs. Li/Li+). Results show that the conductivity of the slurry increases linearly with the addition of KB, and the measured specific capacity of the slurry reaches its theoretical value when the volume ratio of KB to LFP is around 0.2. Based on this ratio, a slurry battery with higher loading of LFP (19.1 wt.% in the slurry) was tested, and a specific capacity of 165 mAh/g at 0.2 mA/cm2 and 102 mAh/g at 5 mA/cm2 was obtained for LFP.

Pressure-controlled injection of guar gum stabilized microscale zerovalent iron for groundwater remediation.

PubMed

Luna, M; Gastone, F; Tosco, T; Sethi, R; Velimirovic, M; Gemoets, J; Muyshondt, R; Sapion, H; Klaas, N; Bastiaens, L

2015-10-01

The paper reports a pilot injection test of microsized zerovalent iron (mZVI) dispersed in a guar gum shear thinning solution. The test was performed in the framework of the EU research project AQUAREHAB in a site in Belgium contaminated by chlorinated aliphatic hydrocarbons (CAHs). The field application was aimed to overcome those critical aspects which hinder mZVI field injection, mainly due to the colloidal instability of ZVI-based suspensions. The iron slurry properties (iron particles size and concentration, polymeric stabilizer type and concentration, slurry viscosity) were designed in the laboratory based on several tests (reactivity tests towards contaminants, sedimentation tests and rheological measurements). The particles were delivered into the aquifer through an injection well specifically designed for controlled-pressure delivery (approximately 10 bars). The well characteristics and the critical pressure of the aquifer (i.e. the injection pressure above which fracturing occurs) were assessed via two innovative injection step rate tests, one performed with water and the other one with guar gum. Based on laboratory and field preliminary tests, a flow regime at the threshold between permeation and preferential flow was selected for mZVI delivery, as a compromise between the desired homogeneous distribution of the mZVI around the injection point (ensured by permeation flow) and the fast and effective injection of the slurry (guaranteed by high discharge rates and injection pressure, resulting in the generation of preferential flow paths). A monitoring setup was designed and installed for the real-time monitoring of relevant parameters during injection, and for a fast determination of the spatial mZVI distribution after injection via non-invasive magnetic susceptibility measurements. Copyright © 2015 Elsevier B.V. All rights reserved.

The Effect of Chemical Amendments Used for Phosphorus Abatement on Greenhouse Gas and Ammonia Emissions from Dairy Cattle Slurry: Synergies and Pollution Swapping.

PubMed

Brennan, Raymond B; Healy, Mark G; Fenton, Owen; Lanigan, Gary J

2015-01-01

Land application of cattle slurry can result in incidental and chronic phosphorus (P) loss to waterbodies, leading to eutrophication. Chemical amendment of slurry has been proposed as a management practice, allowing slurry nutrients to remain available to plants whilst mitigating P losses in runoff. The effectiveness of amendments is well understood but their impacts on other loss pathways (so-called 'pollution swapping' potential) and therefore the feasibility of using such amendments has not been examined to date. The aim of this laboratory scale study was to determine how the chemical amendment of slurry affects losses of NH3, CH4, N2O, and CO2. Alum, FeCl2, Polyaluminium chloride (PAC)- and biochar reduced NH3 emissions by 92, 54, 65 and 77% compared to the slurry control, while lime increased emissions by 114%. Cumulative N2O emissions of cattle slurry increased when amended with alum and FeCl2 by 202% and 154% compared to the slurry only treatment. Lime, PAC and biochar resulted in a reduction of 44, 29 and 63% in cumulative N2O loss compared to the slurry only treatment. Addition of amendments to slurry did not significantly affect soil CO2 release during the study while CH4 emissions followed a similar trend for all of the amended slurries applied, with an initial increase in losses followed by a rapid decrease for the duration of the study. All of the amendments examined reduced the initial peak in CH4 emissions compared to the slurry only treatment. There was no significant effect of slurry amendments on global warming potential (GWP) caused by slurry land application, with the exception of biochar. After considering pollution swapping in conjunction with amendment effectiveness, the amendments recommended for further field study are PAC, alum and lime. This study has also shown that biochar has potential to reduce GHG losses arising from slurry application.

The Effect of Chemical Amendments Used for Phosphorus Abatement on Greenhouse Gas and Ammonia Emissions from Dairy Cattle Slurry: Synergies and Pollution Swapping

PubMed Central

Brennan, Raymond B.; Healy, Mark G.; Fenton, Owen; Lanigan, Gary J.

2015-01-01

Land application of cattle slurry can result in incidental and chronic phosphorus (P) loss to waterbodies, leading to eutrophication. Chemical amendment of slurry has been proposed as a management practice, allowing slurry nutrients to remain available to plants whilst mitigating P losses in runoff. The effectiveness of amendments is well understood but their impacts on other loss pathways (so-called ‘pollution swapping’ potential) and therefore the feasibility of using such amendments has not been examined to date. The aim of this laboratory scale study was to determine how the chemical amendment of slurry affects losses of NH3, CH4, N2O, and CO2. Alum, FeCl2, Polyaluminium chloride (PAC)- and biochar reduced NH3 emissions by 92, 54, 65 and 77% compared to the slurry control, while lime increased emissions by 114%. Cumulative N2O emissions of cattle slurry increased when amended with alum and FeCl2 by 202% and 154% compared to the slurry only treatment. Lime, PAC and biochar resulted in a reduction of 44, 29 and 63% in cumulative N2O loss compared to the slurry only treatment. Addition of amendments to slurry did not significantly affect soil CO2 release during the study while CH4 emissions followed a similar trend for all of the amended slurries applied, with an initial increase in losses followed by a rapid decrease for the duration of the study. All of the amendments examined reduced the initial peak in CH4 emissions compared to the slurry only treatment. There was no significant effect of slurry amendments on global warming potential (GWP) caused by slurry land application, with the exception of biochar. After considering pollution swapping in conjunction with amendment effectiveness, the amendments recommended for further field study are PAC, alum and lime. This study has also shown that biochar has potential to reduce GHG losses arising from slurry application. PMID:26053923

Distribution of dehalogenation activity in subseafloor sediments of the Nankai Trough subduction zone

PubMed Central

Futagami, Taiki; Morono, Yuki; Terada, Takeshi; Kaksonen, Anna H.; Inagaki, Fumio

2013-01-01

Halogenated organic matter buried in marine subsurface sediment may serve as a source of electron acceptors for anaerobic respiration of subseafloor microbes. Detection of a diverse array of reductive dehalogenase-homologous (rdhA) genes suggests that subseafloor organohalide-respiring microbial communities may play significant ecological roles in the biogeochemical carbon and halogen cycle in the subseafloor biosphere. We report here the spatial distribution of dehalogenation activity in the Nankai Trough plate-subduction zone of the northwest Pacific off the Kii Peninsula of Japan. Incubation experiments with slurries of sediment collected at various depths and locations showed that degradation of several organohalides tested only occurred in the shallow sedimentary basin, down to 4.7 metres below the seafloor, despite detection of rdhA in the deeper sediments. We studied the phylogenetic diversity of the metabolically active microbes in positive enrichment cultures by extracting RNA, and found that Desulfuromonadales bacteria predominate. In addition, for the isolation of genes involved in the dehalogenation reaction, we performed a substrate-induced gene expression screening on DNA extracted from the enrichment cultures. Diverse DNA fragments were obtained and some of them showed best BLAST hit to known organohalide respirers such as Dehalococcoides, whereas no functionally known dehalogenation-related genes such as rdhA were found, indicating the need to improve the molecular approach to assess functional genes for organohalide respiration. PMID:23479745

Distribution of dehalogenation activity in subseafloor sediments of the Nankai Trough subduction zone.

PubMed

Futagami, Taiki; Morono, Yuki; Terada, Takeshi; Kaksonen, Anna H; Inagaki, Fumio

2013-04-19

Halogenated organic matter buried in marine subsurface sediment may serve as a source of electron acceptors for anaerobic respiration of subseafloor microbes. Detection of a diverse array of reductive dehalogenase-homologous (rdhA) genes suggests that subseafloor organohalide-respiring microbial communities may play significant ecological roles in the biogeochemical carbon and halogen cycle in the subseafloor biosphere. We report here the spatial distribution of dehalogenation activity in the Nankai Trough plate-subduction zone of the northwest Pacific off the Kii Peninsula of Japan. Incubation experiments with slurries of sediment collected at various depths and locations showed that degradation of several organohalides tested only occurred in the shallow sedimentary basin, down to 4.7 metres below the seafloor, despite detection of rdhA in the deeper sediments. We studied the phylogenetic diversity of the metabolically active microbes in positive enrichment cultures by extracting RNA, and found that Desulfuromonadales bacteria predominate. In addition, for the isolation of genes involved in the dehalogenation reaction, we performed a substrate-induced gene expression screening on DNA extracted from the enrichment cultures. Diverse DNA fragments were obtained and some of them showed best BLAST hit to known organohalide respirers such as Dehalococcoides, whereas no functionally known dehalogenation-related genes such as rdhA were found, indicating the need to improve the molecular approach to assess functional genes for organohalide respiration.

The differences between soil grouting with cement slurry and cement-water glass slurry

NASA Astrophysics Data System (ADS)

Zhu, Mingting; Sui, Haitong; Yang, Honglu

2018-01-01

Cement slurry and cement-water glass slurry are the most widely applied for soil grouting reinforcement project. The viscosity change of cement slurry is negligible during grouting period and presumed to be time-independent while the viscosity of cement-water glass slurry increases with time quickly and is presumed to be time-dependent. Due to the significantly rheology differences between them, the grouting quality and the increasing characteristics of grouting parameters may be different, such as grouting pressure, grouting surrounding rock pressure, i.e., the change of surrounding rock pressure deduced by grouting pressure. Those are main factors for grouting design. In this paper, a large-scale 3D grouting simulation device was developed to simulate the surrounding curtain grouting for a tunnel. Two series of surrounding curtain grouting experiments under different geo-stress of 100 kPa, 150 kPa and 200 kPa were performed. The overload test on tunnel was performed to evaluate grouting effect of all surrounding curtain grouting experiments. In the present results, before 240 seconds, the grouting pressure increases slowly for both slurries; after 240 seconds the increase rate of grouting pressure for cement-water glass slurry increases quickly while that for cement slurry remains roughly constant. The increasing trend of grouting pressure for cement-water glass is similar to its viscosity. The setting time of cement-water glass slurry obtained from laboratory test is less than that in practical grouting where grout slurry solidifies in soil. The grouting effect of cement-water glass slurry is better than that of cement slurry and the grouting quality decreases with initial pressure.

Investigation of hexavalent chromium sorption in serpentine sediments

NASA Astrophysics Data System (ADS)

Mpouras, Thanasis; Chrysochoou, Maria; Dermatas, Dimitris

2017-02-01

In this study the removal of hexavalent chromium (Cr6 +) by serpentine sediments was investigated in order to delineate Cr6 + sorption behavior in aquifers with ultramafic geologic background. Batch experiments were conducted in order to determine the influence of several parameters on Cr6 + removal, including the pH of the sediment solution, mineralogy, sediment's particle size and Cr6 + initial concentration. The results showed that Cr6 + removal was due to both adsorption and reduction phenomena. Reduction was attributed to the presence of a magnetic fraction in the sediment, mostly related to magnetite, which contributed almost 50% of the total removal in the pH range 3-7. Adsorption behavior was dominated by the finer sediment fraction (d < 0.075 mm). The amount of Cr6 + adsorbed was constant in the pH range 3-7, while it decreased sharply in the range 7-8.5. Cr6 + adsorption was found to increase and decrease proportionally with increasing initial Cr6 + concentration of and particle size, respectively. The linear Langmuir and Freundlich adsorption isotherms were used to describe the experimental data, with Freundlich providing a better fit to determine distribution factors for transport modeling.

Improved flotation performance of hematite fines using citric acid as a dispersant

NASA Astrophysics Data System (ADS)

Luo, Xi-mei; Yin, Wan-zhong; Sun, Chuan-yao; Wang, Nai-ling; Ma, Ying-qiang; Wang, Yun-fan

2016-10-01

In this study, citric acid was used as a dispersant to improve the flotation performance of hematite fines. The effect and mechanism of citric acid on the reverse flotation of hematite fines were investigated by flotation tests, sedimentation experiments, scanning electron microscopy (SEM), zeta-potential measurements, and X-ray photoelectron spectroscopy (XPS). The results of SEM analysis and flotation tests reveal that a strong heterocoagulation in the form of slime coating or coagulation in hematite fine slurry affects the beneficiation of hematite ores by froth flotation. The addition of a small amount of citric acid (less than 300 g/t) favorably affects the reverse flotation of hematite fines by improving particle dispersion. The results of sedimentation experiments, zeta-potential measurements, and XPS measurements demonstrate that citric acid adsorbs onto hematite and quartz surfaces via hydrogen bonding, thereby reducing the zeta potentials of mineral surfaces, strengthening the electrical double-layer repulsion between mineral particles, and dispersing the pulp particles.

SLUDGE BATCH 4 BASELINE MELT RATE FURNACE AND SLURRY-FED MELT RATE FURNACE TESTS WITH FRITS 418 AND 510 (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, M. E.; Jones, T. M.; Miller, D. H.

Several Slurry-Fed Melt Rate Furnace (SMRF) tests with earlier projections of the Sludge Batch 4 (SB4) composition have been performed.1,2 The first SB4 SMRF test used Frits 418 and 320, however it was found after the test that the REDuction/OXidation (REDOX) correlation at that time did not have the proper oxidation state for manganese. Because the manganese level in the SB4 sludge was higher than previous sludge batches tested, the impact of the higher manganese oxidation state was greater. The glasses were highly oxidized and very foamy, and therefore the results were inconclusive. After resolving this REDOX issue, Frits 418,more » 425, and 503 were tested in the SMRF with the updated baseline SB4 projection. Based on dry-fed Melt Rate Furnace (MRF) tests and the above mentioned SMRF tests, two previous frit recommendations were made by the Savannah River National Laboratory (SRNL) for processing of SB4 in the Defense Waste Processing Facility (DWPF). The first was Frit 503 based on the June 2006 composition projections.3 The recommendation was changed to Frit 418 as a result of the October 2006 composition projections (after the Tank 40 decant was implemented as part of the preparation plan). However, the start of SB4 processing was delayed due to the control room consolidation outage and the repair of the valve box in the Tank 51 to Tank 40 transfer line. These delays resulted in changes to the projected SB4 composition. Due to the slight change in composition and based on preliminary dry-fed MRF testing, SRNL believed that Frit 510 would increase throughput in processing SB4 in DWPF. Frit 418, which was used in processing Sludge Batch 3 (SB3), was a viable candidate and available in DWPF. Therefore, it was used during the initial SB4 processing. Due to the potential for higher melt rates with Frit 510, SMRF tests with the latest SB4 composition (1298 canisters) and Frits 510 and 418 were performed at a targeted waste loading (WL) of 35%. The '1298 canisters' describes the number of equivalent canisters that would be produced from the beginning of the current contract period before SB3 is blended with SB4. The melt rate for the SMRF SB4/Frit 510 test was 14.6 grams/minute. Due to cold cap mounding problems with the SMRF SB4/Frit 418 feed at 50 weight % solids that prevented a melt rate determination, this feed was diluted to 45 weight % solids. The melt rate for this diluted feed was 8.9 grams/minute. A correction factor of 1.2 for estimating the melt rate at 50 weight % solids from 45 weight % solids test results (based on previous SMRF testing5) was then used to estimate a melt rate of 10.7 grams/minute for SB4/Frit 418 at 50 weight % solids. Therefore, the use of Frit 510 versus Frit 418 with SB4 resulted in a higher melt rate (14.6 versus an estimated 10.7 grams/minute). For reference, a previous SMRF test with SB3/Frit 418 feed at 35% waste loading and 50 weight % solids resulted in a melt rate of 14.1 grams/minute. Therefore, depending on the actual feed rheology, the use of Frit 510 with SB4 could result in similar melt rates as experienced with SB3/Frit 418 feed in the DWPF.« less

Transport of Cryptosporidium parvum Oocysts in Soil Columns following Applications of Raw and Separated Liquid Slurries

PubMed Central

Petersen, Heidi H.; Enemark, Heidi L.; Olsen, Annette; Amin, M. G. Mostofa

2012-01-01

The potential for the transport of viable Cryptosporidium parvum oocysts through soil to land drains and groundwater was studied using simulated rainfall and intact soil columns which were applied raw slurry or separated liquid slurry. Following irrigation and weekly samplings over a 4-week period, C. parvum oocysts were detected from all soil columns regardless of slurry type and application method, although recovery rates were low (<1%). Soil columns with injected liquid slurry leached 73 and 90% more oocysts compared to columns with injected and surface-applied raw slurries, respectively. Among leachate samples containing oocysts, 44/72 samples yielded viable oocysts as determined by a dye permeability assay (DAPI [4′,6′-diamidino-2-phenylindole]/propidium iodide) with the majority (41%) of viable oocysts found in leachate from soil columns with added liquid slurry. The number of viable oocysts was positively correlated (r = 0.63) with the total number of oocysts found. Destructively sampling of the soil columns showed that type of slurry and irrigation played a role in the vertical distribution of oocysts, with more oocysts recovered from soil columns added liquid slurry irrespective of the irrigation status. Further studies are needed to determine the effectiveness of different slurry separation technologies to remove oocysts and other pathogens, as well as whether the application of separated liquid slurry to agricultural land may represent higher risks for groundwater contamination compared to application of raw slurry. PMID:22706058

DWPF simulant CPC studies for SB8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopman, D. C.; Zamecnik, J. R.

2013-06-25

The Savannah River National Laboratory (SRNL) accepted a technical task request (TTR) from Waste Solidification Engineering to perform simulant tests to support the qualification of Sludge Batch 8 (SB8) and to develop the flowsheet for SB8 in the Defense Waste Processing Facility (DWPF). These efforts pertained to the DWPF Chemical Process Cell (CPC). Separate studies were conducted for frit development and glass properties (including REDOX). The SRNL CPC effort had two primary phases divided by the decision to drop Tank 12 from the SB8 constituents. This report focuses on the second phase with SB8 compositions that do not contain themore » Tank 12 piece. A separate report will document the initial phase of SB8 testing that included Tank 12. The second phase of SB8 studies consisted of two sets of CPC studies. The first study involved CPC testing of an SB8 simulant for Tank 51 to support the CPC demonstration of the washed Tank 51 qualification sample in the SRNL Shielded Cells facility. SB8-Tank 51 was a high iron-low aluminum waste with fairly high mercury and moderate noble metal concentrations. Tank 51 was ultimately washed to about 1.5 M sodium which is the highest wash endpoint since SB3-Tank 51. This study included three simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) cycle and Slurry Mix Evaporator (SME) cycle with the sludge-only flowsheet at nominal DWPF processing conditions and three different acid stoichiometries. These runs produced a set of recommendations that were used to guide the successful SRNL qualification SRAT/SME demonstration with actual Tank 51 washed waste. The second study involved five SRAT/SME runs with SB8-Tank 40 simulant. Four of the runs were designed to define the acid requirements for sludge-only processing in DWPF with respect to nitrite destruction and hydrogen generation. The fifth run was an intermediate acid stoichiometry demonstration of the coupled flowsheet for SB8. These runs produced a set of processing recommendations for DWPF along with some data related to Safety Class documentation at DWPF. Some significant observations regarding SB8 follow: Reduced washing in Tank 51 led to an increase in the wt.% soluble solids of the DWPF feed. If wt.% total solids for the SRAT and SME product weren’t adjusted upward to maintain insoluble solids levels similar to past sludge batches, then the rheological properties of the slurry went below the low end of the DWPF design bases for the SRAT and SME. Much higher levels of dissolved manganese were found in the SRAT and SME products than in recent sludge batches. Closed crucible melts were more reduced than expected. The working hypothesis is that the soluble Mn is less oxidizing than assumed in the REDOX calculations. A change in the coefficient for Mn in the REDOX equation was recommended in a separate report. The DWPF (Hsu) stoichiometric acid equation was examined in detail to better evaluate how to control acid in DWPF. The existing DWPF equation can likely be improved without changing the required sample analyses through a paper study using existing data. The recommended acid stoichiometry for initial SB8 SRAT batches is 115-120% stoichiometry until some processing experience is gained. The conservative range (based on feed properties) of stoichiometric factors derived in this study was from 110-147%, but SRNL recommends using only the lower half of this range, 110-126% even after initial batches provide processing experience. The stoichiometric range for sludge-only processing appears to be suitable for coupled operation based on results from the run in the middle of the range. Catalytic hydrogen was detectable (>0.005 vol%) in all SRAT and SME cycles. Hydrogen reached 30-35% of the SRAT and SME limits at the mid-point of the stoichiometry window (bounding noble metals and acid demand).« less

Isotopic exchangeability as a measure of the available fraction of the human pharmaceutical carbamazepine in river sediment.

PubMed

Williams, Mike; Kookana, Rai

2010-08-01

Cabamazepine (CBZ), an antiepileptic pharmaceutical compound, is a pollutant of aquatic ecosystems entering via wastewater treatment plants that is considered to be persistent to degradation. An isotope exchange technique was employed using radiolabelled CBZ as a model compound, to determine the amount of isotopic exchangeability of CBZ in river sediment. The amount of isotopically exchangeable CBZ was used as an estimate of the extent of desorption hysteresis in solution from river sediment, including a treatment where the sediment was amended with black carbon. The isotopically exchangeable CBZ was measured by equilibrating 12C-CBZ with sediment for 0 to 28 days followed by a 24 hour equilibration with 14C-CBZ at the end of the incubation period. The isotopically exchangeable fraction of CBZ decreased over time in the sediment, particularly following amendment with black carbon. This has important implications for the fate of CBZ, which, apart from being resistant to degradation, is constantly released into aquatic ecosystems from wastewater treatment plants. This study demonstrates the availability of a relatively quick and simple alternative to batch desorption techniques for the assessment of the available fraction of organic compounds in sediments following their release into aquatic ecosystems. 2010. Published by Elsevier B.V. All rights reserved.

Continuous inline blending of antimisting kerosene

NASA Technical Reports Server (NTRS)

Parikh, P.; Yavrouian, A.; Sarohia, V.

1985-01-01

A continuous inline blender was developed to blend polymer slurries with a stream of jet A fuel. The viscosity of the slurries ranged widely. The key element of the blender was a static mixer placed immediately downstream of the slurry injection point. A positive displacement gear pump for jet A was employed, and a progressive cavity rotary screw pump was used for slurry pumping. Turbine flow meters were employed for jet A metering while the slurry flow rate was calibrated against the pressure drop in the injection tube. While using one of the FM-9 variant slurries, a provision was made for a time delay between the addition of slurry and the addition of amine sequentially into the jet A stream.

Effects of cattle slurry acidification on ammonia and methane evolution during storage.

PubMed

Petersen, Søren O; Andersen, Astrid J; Eriksen, Jørgen

2012-01-01

Slurry acidification before storage is known to reduce NH(3) emissions, but recent observations have indicated that CH(4) emissions are also reduced. We investigated the evolution of CH(4) from fresh and aged cattle slurry during 3 mo of storage as influenced by pH adjustment to 5.5 with sulfuric acid. In a third storage experiment, cattle slurry acidified with commercial equipment on two farms was incubated. In the manipulation experiments, effects of acid and sulfate were distinguished by adding hydrochloric acid and potassium sulfate separately or in combination, rather than sulfuric acid. In one experiment sulfur was also added to slurry as the amino acid methionine in separate treatments. In each treatment 20-kg portions of slurry (n = 4) were stored for 95 d. All samples were subsampled nine to 10 times for determination of NH(3) and CH(4) evolution rates using a 2-L flow-through system. In all experiments, the pH of acidified cattle slurry increased gradually to between 6.5 and 7. Acidification of slurry reduced the evolution of CH(4) by 67 to 87%. The greatest reduction was observed with aged cattle slurry, which had a much higher potential for CH(4) production than fresh slurry. Sulfate and methionine amendment to cattle slurry without pH adjustment also significantly inhibited methanogenesis, probably as a result of sulfide production. The study suggests that complex microbial interactions involving sulfur transformations and pH determine the potential for CH(4) emission during storage of cattle slurry, and that slurry acidification may be a cost-effective greenhouse gas mitigation option. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Retention and chemical speciation of uranium in an oxidized wetland sediment from the Savannah River Site.

PubMed

Li, Dien; Seaman, John C; Chang, Hyun-Shik; Jaffe, Peter R; Koster van Groos, Paul; Jiang, De-Tong; Chen, Ning; Lin, Jinru; Arthur, Zachary; Pan, Yuanming; Scheckel, Kirk G; Newville, Matthew; Lanzirotti, Antonio; Kaplan, Daniel I

2014-05-01

Uranium speciation and retention mechanisms onto Savannah River Site (SRS) wetland sediments was studied using batch (ad)sorption experiments, sequential extraction, U L3-edge X-ray absorption near-edge structure (XANES) spectroscopy, fluorescence mapping and μ-XANES. Under oxidized conditions, U was highly retained by the SRS wetland sediments. In contrast to other similar but much lower natural organic matter (NOM) sediments, significant sorption of U onto the SRS sediments was observed at pH < 4 and pH > 8. Sequential extraction indicated that the U species were primarily associated with the acid soluble fraction (weak acetic acid extractable) and organic fraction (Na-pyrophosphate extractable). Uranium L3-edge XANES spectra of the U-bound sediments were nearly identical to that of uranyl acetate. Based on fluorescence mapping, U and Fe distributions in the sediment were poorly correlated, U was distributed throughout the sample and did not appear as isolated U mineral phases. The primary oxidation state of U in these oxidized sediments was U(VI), and there was little evidence that the high sorptive capacity of the sediments could be ascribed to abiotic or biotic reduction to the less soluble U(IV) species or to secondary mineral formation. Collectively, this study suggests that U may be strongly bound to wetland sediments, not only under reducing conditions by reductive precipitation, but also under oxidizing conditions through NOM-uranium bonding. Published by Elsevier Ltd.

High throughput screening of ligand binding to macromolecules using high resolution powder diffraction

DOEpatents

Von Dreele, Robert B.; D'Amico, Kevin

2006-10-31

A process is provided for the high throughput screening of binding of ligands to macromolecules using high resolution powder diffraction data including producing a first sample slurry of a selected polycrystalline macromolecule material and a solvent, producing a second sample slurry of a selected polycrystalline macromolecule material, one or more ligands and the solvent, obtaining a high resolution powder diffraction pattern on each of said first sample slurry and the second sample slurry, and, comparing the high resolution powder diffraction pattern of the first sample slurry and the high resolution powder diffraction pattern of the second sample slurry whereby a difference in the high resolution powder diffraction patterns of the first sample slurry and the second sample slurry provides a positive indication for the formation of a complex between the selected polycrystalline macromolecule material and at least one of the one or more ligands.

Recovery and validation of historical sediment quality data from coastal and estuarine areas: An integrated approach

USGS Publications Warehouse

Manheim, F.T.; Buchholtz ten Brink, Marilyn R.; Mecray, E.L.

1998-01-01

A comprehensive database of sediment chemistry and environmental parameters has been compiled for Boston Harbor and Massachusetts Bay. This work illustrates methodologies for rescuing and validating sediment data from heterogeneous historical sources. It greatly expands spatial and temporal data coverage of estuarine and coastal sediments. The database contains about 3500 samples containing inorganic chemical, organic, texture and other environmental data dating from 1955 to 1994. Cooperation with local and federal agencies as well as universities was essential in locating and screening documents for the database. More than 80% of references utilized came from sources with limited distribution (gray literature). Task sharing was facilitated by a comprehensive and clearly defined data dictionary for sediments. It also served as a data entry template and flat file format for data processing and as a basis for interpretation and graphical illustration. Standard QA/QC protocols are usually inapplicable to historical sediment data. In this work outliers and data quality problems were identified by batch screening techniques that also provide visualizations of data relationships and geochemical affinities. No data were excluded, but qualifying comments warn users of problem data. For Boston Harbor, the proportion of irreparable or seriously questioned data was remarkably small (<5%), although concentration values for metals and organic contaminants spanned 3 orders of magnitude for many elements or compounds. Data from the historical database provide alternatives to dated cores for measuring changes in surficial sediment contamination level with time. The data indicate that spatial inhomogeneity in harbor environments can be large with respect to sediment-hosted contaminants. Boston Inner Harbor surficial sediments showed decreases in concentrations of Cu, Hg, and Zn of 40 to 60% over a 17-year period.A comprehensive database of sediment chemistry and environmental parameters has been compiled for Boston Harbor and Massachusetts Bay. This work illustrates methodologies for rescuing and validating sediment data from heterogeneous historical sources. It greatly expands spatial and temporal data coverage of estuarine and coastal sediments. The database contains about 3500 samples containing inorganic chemical, organic, texture and other environmental data dating from 1995 to 1994. Cooperation with local and federal agencies as well as universities was essential in locating and screening documents for the database. More than 80% of references utilized came from sources with limited distribution (gray Task sharing was facilitated by a comprehensive and clearly defined data dictionary for sediments. It also served as a data entry template and flat file format for data processing and as a basis for interpretation and graphical illustration. Standard QA/QC protocols are usually inapplicable to historical sediment data. In this work outliers and data quality problems were identified by batch screening techniques that also provide visualizations of data relationships and geochemical affinities. No data were excluded, but qualifying comments warn users of problem data. For Boston Harbor, the proportion of irreparable or seriously questioned data was remarkably small (<5%), although concentration values for metals and organic contaminants spanned 3 orders of magnitude for many elements or compounds. Data from the historical database provide alternatives to dated cores for measuring changes in surficial sediment contamination level with time. The data indicate that spatial inhomogeneity in harbor environments can be large with respect to sediment-hosted contaminants. Boston Inner Harbor surficial sediments showed decreases in concentrations Cu, Hg, and Zn of 40 to 60% over a 17-year period.

Zeolite Combined with Alum and Polyaluminum Chloride Mixed with Agricultural Slurries Reduces Carbon Losses in Runoff from Grassed Soil Boxes.

PubMed

Murnane, J G; Brennan, R B; Fenton, O; Healy, M G

2016-11-01

Carbon (C) losses from agricultural soils to surface waters can migrate through water treatment plants and result in the formation of disinfection by-products, which are potentially harmful to human health. This study aimed to quantify total organic carbon (TOC) and total inorganic C losses in runoff after application of dairy slurry, pig slurry, or milk house wash water (MWW) to land and to mitigate these losses through coamendment of the slurries with zeolite (2.36-3.35 mm clinoptilolite) and liquid polyaluminum chloride (PAC) (10% AlO) for dairy and pig slurries or liquid aluminum sulfate (alum) (8% AlO) for MWW. Four treatments under repeated 30-min simulated rainfall events (9.6 mm h) were examined in a laboratory study using grassed soil runoff boxes (0.225 m wide, 1 m long; 10% slope): control soil, unamended slurries, PAC-amended dairy and pig slurries (13.3 and 11.7 kg t, respectively), alum-amended MWW (3.2 kg t), combined zeolite and PAC-amended dairy (160 and 13.3 kg t zeolite and PAC, respectively) and pig slurries (158 and 11.7 kg t zeolite and PAC, respectively), and combined zeolite and alum-amended MWW (72 and 3.2 kg t zeolite and alum, respectively). The unamended and amended slurries were applied at net rates of 31, 34, and 50 t ha for pig and dairy slurries and MWW, respectively. Significant reductions of TOC in runoff compared with unamended slurries were measured for PAC-amended dairy and pig slurries (52 and 56%, respectively) but not for alum-amended MWW. Dual zeolite and alum-amended MWW significantly reduced TOC in runoff compared with alum amendment only. We conclude that use of PAC-amended dairy and pig slurries and dual zeolite and alum-amended MWW, although effective, may not be economically viable to reduce TOC losses from organic slurries given the relatively low amounts of TOC measured in runoff from unamended slurries compared with the amounts applied. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Biogas slurry pricing method based on nutrient content

NASA Astrophysics Data System (ADS)

Zhang, Chang-ai; Guo, Honghai; Yang, Zhengtao; Xin, Shurong

2017-11-01

In order to promote biogas-slurry commercialization, A method was put forward to valuate biogas slurry based on its nutrient contents. Firstly, element contents of biogas slurry was measured; Secondly, each element was valuated based on its market price, and then traffic cost, using cost and market effect were taken into account, the pricing method of biogas slurry were obtained lastly. This method could be useful in practical production. Taking cattle manure raw meterial biogas slurry and con stalk raw material biogas slurry for example, their price were 38.50 yuan RMB per ton and 28.80 yuan RMB per ton. This paper will be useful for recognizing the value of biogas projects, ensuring biogas project running, and instructing the cyclic utilization of biomass resources in China.

Evaluation of hybrid slurry resulting from the introduction of additives to mineral slurry.

DOT National Transportation Integrated Search

2011-09-01

Drilled shaft construction often requires the use of drill slurry to maintain borehole stability during excavation : and concreting. Florida Department of Transportation (FDOT) specifications require the use of mineral slurry : for all primary struct...

Method and apparatus for improved wire saw slurry

DOEpatents

Costantini, Michael A.; Talbott, Jonathan A.; Chandra, Mohan; Prasad, Vishwanath; Caster, Allison; Gupta, Kedar P.; Leyvraz, Philippe

2000-09-05

A slurry recycle process for use in free-abrasive machining operations such as for wire saws used in wafer slicing of ingots, where the used slurry is separated into kerf-rich and abrasive-rich components, and the abrasive-rich component is reconstituted into a makeup slurry. During the process, the average particle size of the makeup slurry is controlled by monitoring the condition of the kerf and abrasive components and making necessary adjustments to the separating force and dwell time of the separator apparatus. Related pre-separator and post separator treatments, and feedback of one or the other separator slurry output components for mixing with incoming used slurry and recirculation through the separator, provide further effectiveness and additional control points in the process. The kerf-rich component is eventually or continually removed; the abrasive-rich component is reconstituted into a makeup slurry with a controlled, average particle size such that the products of the free-abrasive machining method using the recycled slurry process of the invention are of consistent high quality with less TTV deviation from cycle to cycle for a prolonged period or series of machining operations.

Accelerated anaerobic dechlorination of DDT in slurry with Hydragric Acrisols using citric acid and anthraquinone-2,6-disulfonate (AQDS).

PubMed

Liu, Cuiying; Xu, Xianghua; Fan, Jianling

2015-12-01

The application of electron donor and electron shuttle substances has a vital influence on electron transfer, thus may affect the reductive dechlorination of 1,1,1-trichoro-2,2-bis(p-chlorophenyl)ethane (DDT) in anaerobic reaction systems. To evaluate the roles of citric acid and anthraquinone-2,6-disulfonate (AQDS) in accelerating the reductive dechlorination of DDT in Hydragric Acrisols that contain abundant iron oxide, a batch anaerobic incubation experiment was conducted in a slurry system with four treatments of (1) control, (2) citric acid, (3) AQDS, and (4) citric acid+AQDS. Results showed that DDT residues decreased by 78.93%-92.11% of the initial quantities after 20days of incubation, and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethane (DDD) was the dominant metabolite. The application of citric acid accelerated DDT dechlorination slightly in the first 8days, while the methanogenesis rate increased quickly, and then the acceleration effect improved after the 8th day while the methanogenesis rate decreased. The amendment by AQDS decreased the Eh value of the reaction system and accelerated microbial reduction of Fe(III) oxides to generate Fe(II), which was an efficient electron donor, thus enhancing the reductive dechlorination rate of DDT. The addition of citric acid+AQDS was most efficient in stimulating DDT dechlorination, but no significant interaction between citric acid and AQDS on DDT dechlorination was observed. The results will be of great significance for developing an efficient in situ remediation strategy for DDT-contaminated sites. Copyright © 2015. Published by Elsevier B.V.

Adsorption of NH4+-N on Chinese loess: Non-equilibrium and equilibrium investigations.

PubMed

Xie, Haijian; Wang, Shaoyi; Qiu, Zhanhong; Jiang, Jianqun

2017-11-01

NH 4 + -N is a crucial pollutant in landfill leachate and can be in high concentrations for a long period of time due to anaerobic condition of landfills. The adsorption properties of NH 4 + -N on the Chinese loess were investigated using Batch test. The influences of ammonium concentration, temperature, reaction time, slurry concentration, and pH on the adsorption process are evaluated. Adsorption kinetics and isotherm behaviors were studied by applying different models to the test data to determine the adsorption parameters. The equilibrating duration was shown to be less than 60 min. The data on adsorption kinetics can be well fitted by the pseudo-second-order kinetics model. According to the Langmuir isotherm model, the adsorption capacity of Chinese loess about NH 4 + -N was predicted to be 72.30 mg g -1 . The uptake of NH 4 + -N by Chinese loess was considered to be the type of physical adsorption on the basis of D-R isotherm analysis. The optimal pH and slurry concentration are 4 and 2 g/50 ml, respectively. According to the calculated values of free energy, enthalpy and entropy change, the adsorption process is determined to be exothermic. The disorder of the system appeared lowest at temperature of 308.15 K. The predicted Gibb's free energies also indicate the adsorption process is endothermic and spontaneous. The FTIR spectrum and EDX analysis showed the adsorption process of NH 4 + involves cation exchange and dissolution of calcite. Copyright © 2017 Elsevier Ltd. All rights reserved.

Discriminative detection and enumeration of microbial life in marine subsurface sediments.

PubMed

Morono, Yuki; Terada, Takeshi; Masui, Noriaki; Inagaki, Fumio

2009-05-01

Detection and enumeration of microbial life in natural environments provide fundamental information about the extent of the biosphere on Earth. However, it has long been difficult to evaluate the abundance of microbial cells in sedimentary habitats because non-specific binding of fluorescent dye and/or auto-fluorescence from sediment particles strongly hampers the recognition of cell-derived signals. Here, we show a highly efficient and discriminative detection and enumeration technique for microbial cells in sediments using hydrofluoric acid (HF) treatment and automated fluorescent image analysis. Washing of sediment slurries with HF significantly reduced non-biological fluorescent signals such as amorphous silica and enhanced the efficiency of cell detachment from the particles. We found that cell-derived SYBR Green I signals can be distinguished from non-biological backgrounds by dividing green fluorescence (band-pass filter: 528/38 nm (center-wavelength/bandwidth)) by red (617/73 nm) per image. A newly developed automated microscope system could take a wide range of high-resolution image in a short time, and subsequently enumerate the accurate number of cell-derived signals by the calculation of green to red fluorescence signals per image. Using our technique, we evaluated the microbial population in deep marine sediments offshore Peru and Japan down to 365 m below the seafloor, which provided objective digital images as evidence for the quantification of the prevailing microbial life. Our method is hence useful to explore the extent of sub-seafloor life in the future scientific drilling, and moreover widely applicable in the study of microbial ecology.

Anaerobic ammonium oxidation mediated by Mn-oxides: from sediment to strain level.

PubMed

Javanaud, Cedric; Michotey, Valerie; Guasco, Sophie; Garcia, Nicole; Anschutz, Pierre; Canton, Mathieu; Bonin, Patricia

2011-11-01

Nitrite and (29)N(2) productions in slurry incubations of anaerobically sediment after (15)NO(3) or (15)NH(4) labelling in the presence of Mn-oxides suggested that anaerobic Mn-oxides mediated nitrification coupled with denitrification in muddy intertidal sediments of Arcachon Bay (SW Atlantic French coast). From this sediment, bacterial strains were isolated and physiologically characterized in terms of Mn-oxides and nitrate reduction as well as potential anaerobic nitrification. One of the isolated strain, identified as Marinobacter daepoensis strain M4AY14, was a denitrifier. Nitrous oxide production by this strain was demonstrated in the absence of nitrate and with Mn-oxides and NH(4) amendment, giving indirect proof of anaerobic nitrate or nitrite production. Anaerobic Mn-oxide-mediated nitrification was confirmed by (29)N(2) production in the presence of (15)NO(3) and (14)NH(4) under denitrifying conditions. Anaerobic nitrification by M4AY14 seemed to occur only in the absence of nitrate, or at nitrate levels lower than that of Mn-oxides. Most of the other isolates were affiliated with the Shewanella genus and were able to use both nitrate and Mn-oxides as electron acceptors. When both electron acceptors were present, whatever their concentrations, nitrate and Mn-oxide reduction co-occurred. These data indicate that bacterial Mn-oxide reduction could be an important process in marine sediments with low oxygen concentrations, and demonstrate for the first time the role of bacteria in anaerobic Mn-mediated nitrification. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

A new magnetic compound fluid slurry and its performance in magnetic field-assisted polishing of oxygen-free copper

NASA Astrophysics Data System (ADS)

Wang, Youliang; Wu, Yongbo; Guo, Huiru; Fujimoto, Masakazu; Nomura, Mitsuyoshi; Shimada, Kunio

2015-05-01

In nano-precision surface finishing of engineering materials using MCF (magnetic compound fluid) slurry, the water-based MCF slurry is preferable from the viewpoint of the environmental issue and the running cost of cleaning workpiece and equipment. However, the uncoated-CIPs (carbonyl-iron-powders) within the conventional MCF slurry have low ability against aqueous corrosion, leading to the performance deterioration and working life shortening of the conventional MCF slurry. This study proposed a new MCF slurry containing ZrO2-coated CIPs instead of the uncoated CIPs. Its performance in the polishing of oxygen-free copper was compared experimentally with that of the conventional one. The results showed that the work-surface finish polished with the new slurry was in the same level as that with the conventional one when the slurry was used soon after prepared, i.e., the settling time was 0 min; however, as the settling time increased the uncoated-CIPs got rusty, leading to a deterioration in the slurry performance. By contrast, no rust was observed on ZrO2-coated CIPs even the settling time reached several days, indicating the employment of ZrO2-coated CIPs prolonged the working-life of the MCF slurry greatly.

The use of additive ceramic hollow spheres on cement slurry to prevent lost circulation in formation `X' having low pressure fracture

NASA Astrophysics Data System (ADS)

Rita, Novia; Mursyidah, Syahindra, Michael

2018-03-01

When drilling, if the hydrostatic pressure is higher than formation pressure (fracture pressure) it will cause lost circulation during cementing process. To solve this problem, hydrostatic pressure of slurry can be decreased by lowering the slurry density by using some additives. Ceramic Hollow Spheres (CHS) is lightweight additive. This additive comes with low specific gravity so it can lowered the slurry density. When the low-density slurry used in cementing process, it can prevent low circulation and fractured formation caused by cement itself. Class G cement is used in this experiment with the standard density of this slurry is 15.8 ppg. With the addition of CHS, slurry density lowered to 12.5 ppg. CHS not only used to lower the slurry density, it also used to make the same properties with the standard slurry even the density has been lowered. Both thickening time and compressive strength have not change if the CHS added to the slurry. With addition of CHS, thickening time at 70 Bc reached in 03 hours 12 minutes. For the compressive strength, 2000 psi reached in 07 hours 07 minutes. Addition of CHS can save more time in cementing process of X formation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sommer, T.; Melick, T.; Morrison, D.

The objective of this DOE sponsored project was to successfully fire coal-water slurry in a fire-tube boiler that was designed for oil/gas firing and establish a data base that will be relevant to a large number of existing installations. Firing slurry in a fire-tube configuration is a very demanding application because of the extremely high heat release rates and the correspondingly low furnace volume where combustion can be completed. Recognizing that combustion efficiency is the major obstacle when firing slurry in a fire-tube boiler, the program was focused on innovative approaches for improving carbon burnout without major modifications to themore » boiler. The boiler system was successfully designed and operated to fire coal-water slurry for extended periods of time with few slurry related operational problems. The host facility was a 3.8 million Btu/hr Cleaver-Brooks fire-tube boiler located on the University of Alabama Campus. A slurry atomizer was designed that provided outstanding atomization and was not susceptible to pluggage. The boiler was operated for over 1000 hours and 12 shipments of slurry were delivered. The new equipment engineered for the coal-water slurry system consisted of the following: combustion air and slurry heaters; cyclone; baghouse; fly ash reinjection system; new control system; air compressor; CWS/gas burner and gas valve train; and storage tank and slurry handling system.« less

Protocol for quantitative tracing of surface water with synthetic DNA

NASA Astrophysics Data System (ADS)

Foppen, J. W.; Bogaard, T. A.

2012-04-01

Based on experiments we carried out in 2010 with various synthetic single stranded DNA markers with a size of 80 nucleotides (ssDNA; Foppen et al., 2011), we concluded that ssDNA can be used to carry out spatially distributed multi-tracer experiments in the environment. Main advantages are in principle unlimited amount of tracers, environmental friendly and tracer recovery at very high dilution rates (detection limit is very low). However, when ssDNA was injected in headwater streams, we found that at selected downstream locations, the total mass recovery was less than 100%. The exact reason for low mass recovery was unknown. In order to start identifying the cause of the loss of mass in these surface waters, and to increase our knowledge of the behaviour of synthetic ssDNA in the environment, we examined the effect of laboratory and field protocols working with artificial DNA by performing numerous batch experiments. Then, we carried out several field tests in different headwater streams in the Netherlands and in Luxembourg. The laboratory experiments consisted of a batch of water in a vessel with in the order of 10^10 ssDNA molecules injected into the batch. The total duration of each experiment was 10 hour, and, at regular time intervals, 100 µl samples were collected in a 1.5 ml Eppendorf vial for qPCR analyses. The waters we used ranged from milliQ water to river water with an Electrical Conductivity of around 400 μS/cm. The batch experiments were performed in different vessel types: polyethylene bottles, polypropylene copolymer bottles , and glass bottles. In addition, two filter types were tested: 1 µm pore size glass fibre filters and 0.2 µm pore size cellulose acetate filters. Lastly, stream bed sediment was added to the batch experiments to quantify interaction of the DNA with sediment. For each field experiment around 10^15 ssDNA molecules were injected, and water samples were collected 100 - 600 m downstream of the point of injection. Additionally, the field tests were performed with salt and deuterium as tracer. To study possible decay by sunlight and/or microbial activity for synthetic DNA, immediately in the field and for the duration of the entire experiment, we carried out batch experiments. All samples were stored in a 1.5 ml Eppendorf vial in a cool-box in dry ice (-80°C). Quantitative PCR on a Mini Opticon (Bio Rad, Hercules, CA, USA) was carried out to determine DNA concentrations in the samples. Results showed the importance of a strict protocol for working with ssDNA as a tracer for quantitative tracing, since ssDNA interacts with surface areas of glass and plastic, depending on water quality and ionic strength. Interaction with the sediment and decay due to sunlight and/or microbial activity was negligible in most cases. The ssDNA protocol was then tested in natural streams. Promising results were obtained using ssDNA as quantitative tracer. The breakthrough curves using ssDNA were similar to the ones of salt or deuterium. We will present the revised protocol to use ssDNA for multi-tracing experiments in natural streams and discuss the opportunities and limitations.

Estimating the sorption of pharmaceuticals based on their pharmacological distribution.

PubMed

Williams, Mike; Ong, Poh L; Williams, Desmond B; Kookana, Rai S

2009-12-01

Pharmaceuticals released into aquatic systems are expected to sorb to sediments to varying degrees. Their sorption is likely to influence their fate and, ultimately, the risk they pose to aquatic organisms. This has led to the European Medicines Agency requiring an assessment of affinity to solids, using batch sorption methods, for the environmental risk assessment (ERA) of new human medicines. However, a large body of data is generated before pharmaceuticals are released onto the market, including their extent of distribution throughout the human body, measured by the volume of distribution (VD). In the present study, batch sorption experiments were undertaken using 12 different soils and sediments to determine whether VD was a good indicator of experimental Kd values for 21 pharmaceuticals. The r2 values obtained from the regressions ranged from 0.39 to 0.76 (with a median value of 0.5) and all regressions were found to be significant. The use of this more comprehensive set of soils and sediments was consistent with previous studies comparing VD and Kd, despite the Kd values of the selected pharmaceuticals varying greatly between soils. The relationship between Kd and VD was greatly improved when zwitterionic antibiotics and carbamazepine were not included, possibly due to complex sorption or pharmacokinetic behavior. There are likely to be a number of factors affecting the sorption of pharmaceuticals that cannot be explained by VD. However, further work may elucidate how these factors can be accounted for, enabling VD to be effectively used to facilitate the ERA of human pharmaceuticals with already available information.

DEMONSTRATION BULLETIN: SLURRY BIODEGRADATION, International Technology Corporation

EPA Science Inventory

This technology uses a slurry-phase bioreactor in which the soil is mixed with water to form a slurry. Microorganisms and nutrients are added to the slurry to enhance the biodegradation process, which converts organic wastes into relatively harmless byproducts of microbial metabo...

Method of making a functionally graded material

DOEpatents

Lauf, Robert J.; Menchhofer, Paul A.; Walls, Claudia A.; Moorhead, Arthur J.

2002-01-01

A gelcasting method of making an internally graded article alternatively includes the steps of: preparing a slurry including a least two different phases suspended in a gelcasting solution, the phases characterized by having different settling characteristics; casting the slurry into a mold having a selected shape; allowing the slurry to stand for a sufficient period of time to permit desired gravitational fractionation in order to achieve a vertical compositional gradient in the molded slurry; gelling the slurry to form a solid gel while preserving the vertical compositional gradient in the molded slurry; drying the gel to form a dried green body; and sintering the dry green body to form a solid object, at least one property thereof varying along the vertical direction because of the compositional gradient in the molded slurry.

Ultrasound Analysis of Slurries

DOEpatents

Soong, Yee and Blackwell, Arthur G.

2005-11-01

An autoclave reactor allows for the ultrasonic analysis of slurry concentration and particle size distribution at elevated temperatures and pressures while maintaining the temperature- and pressure-sensitive ultrasonic transducers under ambient conditions. The reactor vessel is a hollow stainless steel cylinder containing the slurry which includes a stirrer and a N, gas source for directing gas bubbles through the slurry. Input and output transducers are connected to opposed lateral portions of the hollow cylinder for respectively directing sound waves through the slurry and receiving these sound waves after transmission through the slurry, where changes in sound wave velocity and amplitude can be used to measure slurry parameters. Ultrasonic adapters connect the transducers to the reactor vessel in a sealed manner and isolate the transducers from the hostile conditions within the vessel without ultrasonic signal distortion or losses.

Ultrasound Analysis Of Slurries

DOEpatents

Soong, Yee; Blackwell, Arthur G.

2005-11-01

An autoclave reactor allows for the ultrasonic analysis of slurry concentration and particle size distribution at elevated temperatures and pressures while maintaining the temperature- and pressure-sensitive ultrasonic transducers under ambient conditions. The reactor vessel is a hollow stainless steel cylinder containing the slurry which includes a stirrer and a N.sub.2 gas source for directing gas bubbles through the slurry. Input and output transducers are connected to opposed lateral portions of the hollow cylinder for respectively directing sound waves through the slurry and receiving these sound waves after transmission through the slurry, where changes in sound wave velocity and amplitude can be used to measure slurry parameters. Ultrasonic adapters connect the transducers to the reactor vessel in a sealed manner and isolate the transducers from the hostile conditions within the vessel without ultrasonic signal distortion or losses.

Fermentation of Anaerobic Cow Waste as Bio-Slurry Organic Fertilizer and Nitrogen Chemical Fertilizer on Soybean

NASA Astrophysics Data System (ADS)

Yafizham; Sutarno

2018-02-01

The study aimed was to evaluate the effect of bio-slurry organic fertilizer and urea chemical fertilizer combination on fresh material weight, phosphorus and potassium soybean straw, and seed weight per soybean plant plot. The experiment was conducted with a randomized block design with a single treatment repeated 5 times consisting of P0: control (without fertilizer), P1: bio-slurry 10 t/ha + 25 kg of N/ha, P2: bio-slurry 10 t/ha + 50 kg of N/ha, P3: bio-slurry 10 t/ha + 75 kg of N/ha, P4: bio-slurry 10 t/ha + 100 kg of N/ha and P5: bio-slurry 10 t/ha. The results showed that bio-slurry treatment of 10 t/ha + 25 kg of N/ha resulted in the highest fresh weight and dry weight of soybean plants, respectively of 240.7 g and 22.33 g, but not significantly different from the bio-slurry treatment of 10 t/ha + 50 kg of N/ha which yielded fresh weight of 197.7 g and a dry weight of 19.08 g. P production of 10.23 g per plant was significantly higher than other treatments but didn’t differ significantly between P2 and P4 treatments of 8.05 and 7.17 g per plant. The bio-slurry treatment of 10 t/ha + 25 kg of N/ha also yielded K of 6.46 g per plant butn’t unlike the bio-slurry treatment of 10 t/ha + 50 kg of N/ha. While the number of pods per plant and weight of 100 grains of the highest soybean seeds were also produced from bio-slurry treatment of 10 t/ha + 25 kg of N/ha.

Laboratory estimates of trace gas emissions following surface application and injection of cattle slurry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flessa, H.; Beese, F.

2000-02-01

Applying cattle slurry to soil may induce emissions of the greenhouse gases N{sub 2}O and CH{sub 4}. Their objective was to determine the effects of different application techniques (surface application and slit injection) of cattle (Bostaurus) slurry on the decomposition of slurry organic matter and the emissions of N{sub 2}O and CH{sub 4}. The effects of slurry application (43.6 m{sup 3} ha{sup {minus}1}) were studied for 9 wk under controlled laboratory conditions using a soil microcosm system with automated monitoring of the CO{sub 2}, N{sub 2}O, and CH{sub 4} fluxes. The soil used was a silty loam (Ap horizon ofmore » a cambisol) with a constant water-filled pore space of 67% during the experiment. About 38% of the organic matter applied with the slurry was decomposed within 9 wk. Production of CO{sub 2} was not affected by the application technique. Emissions of N{sub 2}O and CH{sub 4} from the injected slurry were significantly higher than from the surface-applied slurry, probably because of restricted aeration at the injected-slurry treatment. Total N{sub 2}O-N emissions were 0.2% (surface application) and 3.3% (slit injection) of the slurry N added. Methane emission occurred only during the first few days following application. The total net flux of CH{sub 4}-C for 2 wk was {minus}12 g ha{sup {minus}1} for the control (CH{sub 4} uptake), 2 g ha{sup {minus}1} for the surface-applied slurry, and 39 g ha{sup {minus}1} for the injected slurry. Slurry injection, which is recommended to reduce NH{sub 3} volatilization, appears to increase emissions of the greenhouse gases N{sub 2}O and CH{sub 4} from the fertilized fields.« less

Lanthanide-labeled clay: A new method for tracing sediment transport in Karst

USGS Publications Warehouse

Mahler, B.J.; Bennett, P.C.; Zimmerman, M.

1998-01-01

Mobile sediment is a fundamental yet poorly characterized aspect of mass transport through karst aquifers. Here the development and field testing of an extremely sensitive particle tracer that may be used to characterize sediment transport in karst aquifers is described. The tracer consists of micron-size montmorillonite particles homoionized to the lanthanide form; after injection and retrieval from a ground water system, the lanthanide ions are chemically stripped from the clay and quantified by high performance liquid chromatography. The tracer meets the following desired criteria: low detection limit; a number of differentiable signatures; inexpensive production and quantification using standard methods; no environmental risks; and hydrodynamic properties similar to the in situ sediment it is designed to trace. The tracer was tested in laboratory batch experiments and field tested in both surface water and ground water systems. In surface water, arrival times of the tracer were similar to those of a conservative water tracer, although a significant amount of material was lost due to settling. Two tracer tests were undertaken in a karst aquifer under different flow conditions. Under normal flow conditions, the time of arrival and peak concentration of the tracer were similar to or preceded that of a conservative water tracer. Under low flow conditions, the particle tracer was not detected, suggesting that in low flow the sediment settles out of suspension and goes into storage.Mobile sediment is a fundamental yet poorly characterized aspect of mass transport through karst aquifers. Here the development and field testing of an extremely sensitive particle tracer that may be used to characterize sediment transport in karst aquifers is described. The tracer consists of micron-size montmorillonite particles homoionized to the lanthanide form; after injection and retrieval from a ground water system, the lanthanide ions are chemically stripped from the clay and quantified by high performance liquid chromatography. The tracer meets the following desired criteria: low detection limit; a number of differentiable signatures; inexpensive production and quantification using standard methods; no environmental risks; and hydrodynamic properties similar to the in situ sediment it is designed to trace. The tracer was tested in laboratory batch experiments and field tested in both surface water and ground water systems. In surface water, arrival times of the tracer were similar to those of a conservative water tracer, although a significant amount of material was lost due to settling. Two tracer tests were undertaken in a karst aquifer under different flow conditions. Under normal flow conditions, the time of arrival and peak concentration of the tracer were similar to or preceded that of a conservative water tracer. Under low flow conditions, the particle tracer was not detected, suggesting that in low flow the sediment settles out of suspension and goes into storage.

DEVELOPMENT OF AN ANTIFOAM TRACKING SYSTEM AS AN OPTION TO SUPPORT THE MELTER OFF-GAS FLAMMABILITY CONTROL STRATEGY AT THE DWPF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, T.; Lambert, D.

The Savannah River National Laboratory (SRNL) has been working with the Savannah River Remediation (SRR) Defense Waste Processing Facility (DWPF) in the development and implementation of an additional strategy for confidently satisfying the flammability controls for DWPF’s melter operation. An initial strategy for implementing the operational constraints associated with flammability control in DWPF was based upon an analytically determined carbon concentration from antifoam. Due to the conservative error structure associated with the analytical approach, its implementation has significantly reduced the operating window for processing and has led to recurrent Slurry Mix Evaporator (SME) and Melter Feed Tank (MFT) remediation. Tomore » address the adverse operating impact of the current implementation strategy, SRR issued a Technical Task Request (TTR) to SRNL requesting the development and documentation of an alternate strategy for evaluating the carbon contribution from antifoam. The proposed strategy presented in this report was developed under the guidance of a Task Technical and Quality Assurance Plan (TTQAP) and involves calculating the carbon concentration from antifoam based upon the actual mass of antifoam added to the process assuming 100% retention. The mass of antifoam in the Additive Mix Feed Tank (AMFT), in the Sludge Receipt and Adjustment Tank (SRAT), and in the SME is tracked by mass balance as part of this strategy. As these quantities are monitored, the random and bias uncertainties affecting their values are also maintained and accounted for. This report documents: 1) the development of an alternate implementation strategy and associated equations describing the carbon concentration from antifoam in each SME batch derived from the actual amount of antifoam introduced into the AMFT, SRAT, and SME during the processing of the batch. 2) the equations and error structure for incorporating the proposed strategy into melter off-gas flammability assessments. Sample calculations of the system are also included in this report. Please note that the system developed and documented in this report is intended as an alternative to the current, analytically-driven system being utilized by DWPF; the proposed system is not intended to eliminate the current system. Also note that the system developed in this report to track antifoam mass in the AMFT, SRAT, and SME will be applicable beyond just Sludge Batch 8. While the model used to determine acceptability of the SME product with respect to melter off-gas flammability controls must be reassessed for each change in sludge batch, the antifoam mass tracking methodology is independent of sludge batch composition and as such will be transferable to future sludge batches.« less

46 CFR Table 2 to Part 153 - Cargoes Not Regulated Under Subchapters D or O of This Chapter When Carried in Bulk on Non...

Code of Federal Regulations, 2013 CFR

2013-10-01

...-ethylamino-6-isopropylamino-5-triazine solution # Choline chloride solution D Clay slurry III Coal slurry III... acid, dimethylamine salt solution * Y Choline chloride solutions Z Clay slurry OS Coal slurry OS...

Uranium fate in Hanford sediment altered by simulated acid waste solutions

DOE PAGES

Gartman, Brandy N.; Qafoku, Nikolla P.; Szecsody, James E.; ...

2015-07-31

Many aspects of U(VI) behavior in sediments that are previously exposed to acidic waste fluids for sufficiently long times to induce significant changes in pH and other physical, mineralogical and chemical properties, are not well documented in the literature. For this reason, we conducted a series of macroscopic batch experiments combined with a variety of bulk characterization studies (Mössbauer and laser spectroscopy), micro-scale inspections (µ-XRF), and molecular scale interrogations (XANES) with the objectives to: i) determine the extent of U(VI) partitioning to Hanford sediments previously exposed to acidic waste simulants (pH = 2 and pH = 5) and under neutralmore » conditions (pH = 8) at varying background solution concentrations (i.e., NaNO 3); ii) determine micron-scale solid phase associated U valence state and phase identity; and iii) provide information for a plausible conceptual model of U(VI) attenuation under waste plume acidic conditions. The results of the batch experiments showed that the acid pre-treated sediment had high affinity for aqueous U(VI), which was removed from solution via two pH dependent and apparently different mechanisms (adsorption at pH = 2 and precipitation at pH = 5). The micro-scale inspections and XANES analyses confirmed that high concentration areas were rich mainly in U(VI), demonstrating that most of the added U(VI) was not reduced to U(IV). The laser spectroscopy data showed that uranyl phosphates {e.g. metaautunite [Ca(UO 2) 2(PO 4) 2•10-12H 2O] and phosphuranylite [KCa(H 3O) 3(UO 2) 7(PO 4) 4O 4•8(H 2O)]} were present in the sediments. They also showed clear differences between the U bearing phases in the experiments conducted in the presence or absence of air. As a result, the data generated from these experiments will help in a better understanding of the reactions and processes that have a significant effect and/or control U mobility.« less

Technetium Reduction and Permanent Sequestration by Abiotic and Biotic Formation of Low-Solubility Sulfide Mineral Phases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tratnyek, Paul G.; Tebo, Bradley M.; Fan, Dimin

One way to minimize the mobility of the Tc VII oxyanion pertechnetate (TcO 4 -) is to effect reduction under sulfidogenic conditions (generated abiotically by Fe 0 or biotically) to form TcS x, which is significantly slower to oxidize than Tc IVO 2. In sediment systems, TcS x and other precipitates may oxidize more slowly due to oxygen diffusion limitations to these low permeability precipitate zones. In addition, the TcO 4 - reduction rate may be more rapid in the presence of sediment because of additional reductive surface phases. This project aims to provide a fundamental understanding of the feasibilitymore » of immobilization of TcO 4 - as TcS x in the vadose zone or groundwater by application nano zero-valent iron (nZVI), and sulfide or sulfate. Biotic batch experiments have used the sulfate-reducing bacterium (SRB) Desulfotomaculum reducens. The iron sulfide mineral mackinawite was generated under these conditions, while vivianite was formed in nZVI only controls. The sulfide/bacteria-containing system consistently reduced aqueous pertechnetate rapidly (> 95% in the first hour), a rate similar to that for the sulfide-free, nZVI only system. Reduced Tc (aged for 3 months) generated in both SRB/nZVI systems was highly resistant to reoxidation. In reduced samples, Tc was found associated with solid phases containing Fe and S (D. reducens/nZVI) or Fe (nZVI only). Experiments using D. reducens without nZVI provided some additional insights. Firstly, stationary phase cultures were able to slowly reduce pertechnetate. Secondly, addition of pertechnetate at the beginning of cell growth (lag phase) resulted in a faster rate of Tc reduction, possibly indicating a direct (e.g. enzymatic) role for D. reducens in Tc reduction. Abiotic batch experiments were conducted with Na 2S as the sulfide source. Pertechnetate reduction was rapid in the presence of sulfide and nZVI, although the rate was suppressed at the higher S/Fe ratios tested. This suppression appeared to be due to the formation of Tc-containing colloids. As with the biotic experiments, pertechnetate reduced under sulfidic conditions was highly resistant to reoxidation. The microscopic morphology of abiotically-transformed nZVI particles varied significantly with those in the biotic experiment, although mackinawite was formed in both systems (as indicated by μXRD and Mössbauer spectroscopy). Preliminary XAS analysis pointed to a mixture of Tc-O and Tc-S binding in the abiotic sulfide/nZVI system, while the major reduced solids under non-sulfidic conditions were TcO 2•nH 2O. The presence of sediment and advective flow to the TcO 4 -/nZVI/sulfide system results in additional processes occurring. Although the natural Hanford sediment used has sufficient available ferrous iron to slowly reduce TcO 4 -, under anaerobic conditions, that rate is orders of magnitude slower than reduction by nZVI/sulfide. Batch and 1-D column experiments showed that the TcO 4 - reduction rate increased with the sediment surface area (with the same nZVI mass). As in batch systems, column studies showed that the presence of sulfide with TcO 4 - at low (2-5 mM) concentrations increased the TcO 4 - reduction rate and high (10-30 mM) sulfide decreased the rate. This change is attributed to the formation of sulfide precipitates on the nZVI and sediment surfaces. Injection of low and high sulfide (i.e. pretreatment) prior to TcO 4 -/sulfide injection also greatly decreased the TcO 4 - reduction rate, likely decreasing the generation of ferrous iron from the nZVI. Although the high sulfide systems have slower Tc reduction rates, 190 times more Tc mass precipitated than in the low sulfide systems and the highest fraction of Tc mass remained immobilized.« less

Modified starch containing liquid fuel slurry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metzger, G.W.

1978-04-04

A substantially water-free, high solids content, stably dispersed combustible fuel slurry is provided, with a method of preparing the slurry. The slurry contains a minor amount of a solid particulate carbonaceous material such as powdered coal, with substantially the entire balance of the slurry being comprised of a liquid hydrocarbon fuel, particularly a heavy fuel oil. In extremely minor amounts are anionic surfactants, particularly soaps, and a stabilizing amount of a starch modified with an anionic polymer.

Slip casting nano-particle powders for making transparent ceramics

DOEpatents

Kuntz, Joshua D [Livermore, CA; Soules, Thomas F [Livermore, CA; Landingham, Richard Lee [Livermore, CA; Hollingsworth, Joel P [Oakland, CA

2011-04-12

A method of making a transparent ceramic including the steps of providing nano-ceramic powders in a processed or unprocessed form, mixing the powders with de-ionized water, the step of mixing the powders with de-ionized water producing a slurry, sonifing the slurry to completely wet the powder and suspend the powder in the de-ionized water, separating very fine particles from the slurry, molding the slurry, and curing the slurry to produce the transparent ceramic.

Effect of organized assemblies. Part 4. Formulation of highly concentrated coal-water slurry using a natural surfactant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debadutta Das; Sagarika Panigrahi; Pramila K. Misra

2008-05-15

Coal-water slurry has received considerable research nowadays due to its ability in substituting energy sources. The present work reports the formulation of highly concentrated coal-water slurry using a natural occurring surface active compound, saponin, extracted from the fruits of plant Sapindous laurifolia. The isolation of saponin from the plant and its surface activity has been discussed. The rheological characteristics of coal-water slurry have been investigated as a function of coal loading, ash content of coal, pH, temperature, and amount of saponin. The viscosity of the slurry and zeta potential are substantially decreased with concomitant shift of the isoelectric point ofmore » coal on adsorption of saponin to it. In the presence of 0.8% of saponin, coal-water slurry containing 64% weight fraction of coal could be achieved. The slurry is stable for a period of as long as 1 month in contrast to 4-5 h in the case of bare coal-water slurry. The results confirm the use of saponin as a suitable additive for coal-water slurry similar to the commercially available additive such as sodium dodecyl sulfate. Basing on the effect of pH on the zeta potential and viscosity of slurry, a suitable mechanism for saponin-coal interaction and orientation of saponin at the coal-water interface has been proposed. 47 refs., 12 figs., 5 tabs.« less

Pseudoplasticity of Propellant Slurry with Varied Aluminium Content for Castability Development

NASA Astrophysics Data System (ADS)

Restasari, A.; Budi, R. S.; Hartaya, K.

2018-04-01

The modification of the percentage of aluminium is necessary to obtain certain specific impulse. But, it affects the pseudoplasticity of propellant in elapsed time that is important in casting. Therefore, this research attempts to investigate the pseudoplasticity of propellant slurry with varied aluminium contents and as time elapsed, the range of percentage of aluminium and time that allows propellant slurry to be well processed. The methods include measuring the viscosity of propellant slurries that contain 6, 8, 10, 12, 14, 16 and 18% of aluminium at varied shear rates until 40 minutes after mixing by using Brookfield viscometer. The graphs of viscosity versus shear rate were made to determine pseudoplasticity index. After that, the graph volume fraction versus pseudoplasticity index were made to be investigated. It is concluded that the more aluminium contents, the slurries with 6 to 12% aluminium contents exhibit more pseudoplastic behaviour, but the slurries with 12 to 16% aluminium exhibit less pseudoplastic. While, slurry of 18% aluminium exhibit high pseudoplasticity. In the correlation with the time, the slurry compositions of 6, 8, 14, 16% aluminium become more pseudoplastic as time elapsed. While, for compositions of 10, 12 and 18% aluminium, the trend becomes contrary. Based on the pseudoplasticity index, propellant slurries that contain 10 and 14% of aluminium are suitable for pressure casting. While for slurries with 6, 8 and 16% of aluminium are also suitable for vacuum casting. All of those suitability are possesed until 40 minutes after mixing. While, the composition of slurries that contain 12 and 18% of aluminium need to be modified to enhanced its castability.

Environmental Fate of Nitroguanidine, Diethyleneglycol Dinitrate, and Hexachloroethane Smoke. Phase 1.

DTIC Science & Technology

1985-12-01

Biotransformation of HOE ........58 (10) Biosorption of HOE ..................614 (11) Biouptake of HOE by Land Plants ......614 b. Other HOE Smoke Products...53 . 21. Batch Sorption of HCE on EPA Sediments #5 and #18 ............... 55 22. Biosorption Partition Coefficient (KB) for HCE...ability of microorganisms to transform HCE was obtained in our preliminary HCE biosorption study, in which a mixture of the four V test organisms

Application of zeolitic material synthesized from thermally treated sediment to the removal of trivalent chromium from wastewater.

PubMed

Guan, Qingyu; Wu, Deyi; Lin, Yan; Chen, Xuechu; Wang, Xinze; Li, Chunjie; He, Shengbing; Kong, Hainan

2009-08-15

Zeolitic materials were synthesized from thermally treated sediment by alkali treatment using different NaOH/sediment ratios. Characterization of the materials was done by XRD, FTIR, cation exchange capacity and specific surface area. Use of high NaOH/sediment ratio favored the formation of zeolite. The potential value of the zeolitic materials for the retention of trivalent chromium from water was examined. The maximum of Cr(III) sorption by the zeolitic materials, determined by a repeated batch equilibration method, ranged from 38.9 to 75.8 mg/g which was much greater than that of the thermally treated sediment (6.3 mg/g). No release of sorbed Cr(III) by 1.0M MgCl(2) at pH 7 was observed but Cr(III) desorption by ionic electrolyte increased with decreasing pH. The zeolitic materials could completely remove Cr(III) from wastewater even in the presence of Na(+) and Ca(2+) with high concentrations with a dose above 2.5 g/L. The pH-dependent desorption behavior and the high selectivity of zeolitic material for Cr(III) were explained by sorption at surface hydroxyl sites and formation of surface precipitates.

Geochemical Impacts of Leaking CO2 from Subsurface Storage Reservoirs on the Fate of Metal Contaminants in an Overlaying Groundwater Aquifer

NASA Astrophysics Data System (ADS)

Shao, H.; Qafoku, N. P.; Lawter, A.; Bowden, M. E.; Brown, C. F.

2014-12-01

The leakage of CO2 and the concomitant upward transport of brine solutions and contaminants from deep storage reservoirs to overlaying groundwater aquifers is considered one of the major risks associated with geologic carbon sequestration (GCS). A systematic understanding of how such leakage would impact the geochemistry of potable aquifers is crucial to the maintenance of environmental quality and the widespread acceptance of GCS. A series of batch and column experiments studies were conducted to understand the fate (mobilization and immobilization) of trace metals, such as Cd and As in the groundwater aquifer after the intrusion of CO2 gas and CO2-saturated fluids containing leached metals from deep subsurface storage reservoirs. Sediments from the High Plains aquifer in Kansas, United States, were used in this investigation, which is part of the National Risk Assessment Partnership Program sponsored by the US DOE. This aquifer was selected to be representative of consolidated sand and gravel/sandstone aquifers overlying potential CO2 sequestration repositories within the continental US. The experiments were conducted at room temperature and atmospheric pressure. The results demonstrated that Cd and As that intrude into groundwater aquifers with the leaking CO2 at initial concentrations of 40 and 114 mg/L, respectively, will be adsorbed on the sediments, in spite of the acidic pH (between 5 and 6) due to CO2 dissolution in the groundwater. Cd concentrations were well below its MCL in both the aqueous solution of the batch study and the effluent of the column study, even for one of the sediment samples which had undetectable amount of carbonate minerals to buffer the pH. Arsenic concentrations were also significantly lower than that in the influent, suggesting that natural sediments have the capacity to mitigate the adverse effects of the CO2 leakage. However, the mitigation capacity of sediments is influenced by its geochemical properties. When there are anions such as phosphate in the sediment, competitive adsorption may occur and result in higher concentrations of toxic metals in the aqueous phase. Results from these investigations will provide useful information to support site selection, risk assessment, and public education efforts associated with geological CO2 storage and sequestration.

Biodegradation of organic compounds in vadose zone and aquifer sediments.

PubMed Central

Konopka, A; Turco, R

1991-01-01

The microbial processes that occur in the subsurface under a typical Midwest agricultural soil were studied. A 26-m bore was installed in November of 1988 at a site of the Purdue University Agronomy Research Center. Aseptic collections of soil materials were made at 17 different depths. Physical analysis indicated that the site contained up to 14 different strata. The site materials were primarily glacial tills with a high carbonate content. The N, P, and organic C contents of sediments tended to decrease with depth. Ambient water content was generally less than the water content, which corresponds to a -0.3-bar equivalent. No pesticides were detected in the samples, and degradation of added 14C-labeled pesticides (atrazine and metolachlor) was not detected in slurry incubations of up to 128 days. The sorption of atrazine and metolachlor was correlated with the clay content of the sediments. Microbial biomass (determined by direct microscopic count, viable count, and phospholipid assay) in the tills was lower than in either the surface materials or the aquifer located at 25 m. The biodegradation of glucose and phenol occurred rapidly and without a lag in samples from the aquifer capillary fringe, saturated zone, and surface soils. In contrast, lag periods and smaller biodegradation rates were found in the till samples. Subsurface sediments are rich in microbial numbers and activity. The most active strata appear to be transmissive layers in the saturated zone. This implies that the availability of water may limit activity in the profile. PMID:1768098

Effect of salinity and inorganic nitrogen concentrations on nitrification and denitrification rates in intertidal sediments and rocky biofilms of the Douro River estuary, Portugal.

PubMed

Magalhães, Catarina M; Joye, Samantha B; Moreira, Rosa M; Wiebe, William J; Bordalo, Adriano A

2005-05-01

The regulatory effects of salinity and inorganic nitrogen compounds on nitrification and denitrification were studied in intertidal sandy sediments and rocky biofilms in the Douro River estuary, Portugal, over a 12-month period. Nitrification and denitrification rates were measured in slurries of field samples and enrichment experiments using the difluoromethane and the acetylene inhibition techniques, respectively. Salinity did not regulate denitrification in either environment, suggesting that halotolerant bacteria dominated the denitrifier communities. However, nitrification rates were stimulated when salinity increased from 0 to 15 practical salinity units. NO3- addition experiments revealed that NO3- availability stimulates denitrification rates in sandy sediments, but not in rocky biofilms; however, in rocky biofilms a positive and linear relationship was observed between denitrification rates and water column NO3- concentrations (r=0.92) during the monthly surveys. The N2O:N2 ratios increased rapidly when NO3- increased from 63 to 363 microM; however, results from monthly surveys showed that environmental parameters other than NO3- availability may be important in controlling the variation in N2O production via denitrification. Ammonium additions to sandy sediments stimulated nitrification rates by 35% for the 20 microM NH4+ addition, but NH4+ appeared to inhibit nitrification at high concentration addition (200 microM NH4+). In contrast, rocky biofilm nitrification was stimulated by 65% when 200 microM NH4+ was added.

Production of ethanol from kitchen waste by using flocculating Saccharomyces cerevisiae KF-7.

PubMed

Wang, Yan-Fang; Tan, Li; Wang, Ting; Sun, Zhao-Yong; Tang, Yue-Qin; Kida, Kenji

2017-02-01

Kitchen waste is rich in carbohydrates and can potentially serve as feedstock for ethanol production. Starch was the primary carbohydrate in kitchen waste obtained from the canteen in the Sichuan University, which was used to evaluate long-term ethanol fermentation performance in this study. The optimal conditions for liquefaction and saccharification of the kitchen waste were as follows: adding α-amylase at 0.3 μL/g glucan for liquefaction at 90°C for 30 min, and adding glucoamylase at 4 μL/g glucan for saccharification at 50°C. Glucose yield obtained under the optimal conditions was over 80%. Addition of cellulase did not enhance glucose yield, but decreased the viscosity of the saccharified slurry. Repeated-batch presaccharification followed by simultaneous saccharification and fermentation of 20 batches was successfully carried out at an aeration of 0.1 vvm. Ethanol concentration of 43.9-45.0 g/L was achieved, corresponding to ethanol yield and productivity of 88.9-91.2% and 3.3-3.5 g/L/h, respectively, and the CO 2 /ethanol molar ratio was approximately 1. Continuous PSSF was stably carried out at a dilution rate of ≤0.3 h -1 . Productivity was 11.5 g/L/h at a dilution rate of 0.3 h -1 . Ethanol concentration and yield were 42.0 g/L and 82.8% at a dilution rate of 0.2 h -1 , respectively.

Sludge batch 9 simulant runs using the nitric-glycolic acid flowsheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Williams, M. S.; Brandenburg, C. H.

Testing was completed to develop a Sludge Batch 9 (SB9) nitric-glycolic acid chemical process flowsheet for the Defense Waste Processing Facility’s (DWPF) Chemical Process Cell (CPC). CPC simulations were completed using SB9 sludge simulant, Strip Effluent Feed Tank (SEFT) simulant and Precipitate Reactor Feed Tank (PRFT) simulant. Ten sludge-only Sludge Receipt and Adjustment Tank (SRAT) cycles and four SRAT/Slurry Mix Evaporator (SME) cycles, and one actual SB9 sludge (SRAT/SME cycle) were completed. As has been demonstrated in over 100 simulations, the replacement of formic acid with glycolic acid virtually eliminates the CPC’s largest flammability hazards, hydrogen and ammonia. Recommended processingmore » conditions are summarized in section 3.5.1. Testing demonstrated that the interim chemistry and Reduction/Oxidation (REDOX) equations are sufficient to predict the composition of DWPF SRAT product and SME product. Additional reports will finalize the chemistry and REDOX equations. Additional testing developed an antifoam strategy to minimize the hexamethyldisiloxane (HMDSO) peak at boiling, while controlling foam based on testing with simulant and actual waste. Implementation of the nitric-glycolic acid flowsheet in DWPF is recommended. This flowsheet not only eliminates the hydrogen and ammonia hazards but will lead to shorter processing times, higher elemental mercury recovery, and more concentrated SRAT and SME products. The steady pH profile is expected to provide flexibility in processing the high volume of strip effluent expected once the Salt Waste Processing Facility starts up.« less

Powder treatment process

DOEpatents

Weyand, J.D.

1988-02-09

Disclosed are: (1) a process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder. 2 figs.

Powder treatment process

DOEpatents

Weyand, John D.

1988-01-01

(1) A process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder.

DEHYDRATION OF DEUTERIUM OXIDE SLURRIES

DOEpatents

Hiskey, C.F.

1959-03-10

A method is presented for recovering heavy water from uranium oxide-- heavy water slurries. The method consists in saturating such slurries with a potassium nitrate-sodium nitrate salt mixture and then allowing the self-heat of the slurry to raise its temperature to a point slightly in excess of 100 deg C, thus effecting complete evaporation of the free heavy water from the slurry. The temperature of the slurry is then allowed to reach 300 to 900 deg C causing fusion of the salt mixture and expulsion of the water of hydration. The uranium may be recovered from the fused salt mixture by treatment with water to leach the soluble salts away from the uranium-containing residue.

Process for blending coal with water immiscible liquid

DOEpatents

Heavin, Leonard J.; King, Edward E.; Milliron, Dennis L.

1982-10-26

A continuous process for blending coal with a water immiscible liquid produces a uniform, pumpable slurry. Pulverized raw feed coal and preferably a coal derived, water immiscible liquid are continuously fed to a blending zone (12 and 18) in which coal particles and liquid are intimately admixed and advanced in substantially plug flow to form a first slurry. The first slurry is withdrawn from the blending zone (12 and 18) and fed to a mixing zone (24) where it is mixed with a hot slurry to form the pumpable slurry. A portion of the pumpable slurry is continuously recycled to the blending zone (12 and 18) for mixing with the feed coal.

Fuel injection of coal slurry using vortex nozzles and valves

DOEpatents

Holmes, Allen B.

1989-01-01

Injection of atomized coal slurry fuel into an engine combustion chamber is achieved at relatively low pressures by means of a vortex swirl nozzle. The outlet opening of the vortex nozzle is considerably larger than conventional nozzle outlets, thereby eliminating major sources of failure due to clogging by contaminants in the fuel. Control fluid, such as air, may be used to impart vorticity to the slurry and/or purge the nozzle of contaminants during the times between measured slurry charges. The measured slurry charges may be produced by a diaphragm pump or by vortex valves controlled by a separate control fluid. Fluidic circuitry, employing vortex valves to alternatively block and pass cool slurry fuel flow, is disclosed.

Impact of sulfate pollution on anaerobic biogeochemical cycles in a wetland sediment.

PubMed

Baldwin, Darren S; Mitchell, Alison

2012-03-15

The impact of sulfate pollution is increasingly being seen as an issue in the management of inland aquatic ecosystems. In this study we use sediment slurry experiments to explore the addition of sulfate, with or without added carbon, on the anaerobic biogeochemical cycles in a wetland sediment that previously had not been exposed to high levels of sulfate. Specifically we looked at the cycling of S (sulfate, dissolved and particulate sulfide--the latter measured as acid volatile sulfide; AVS), C (carbon dioxide, bicarbonate, methane and the short chain volatile fatty acids formate, acetate, butyrate and propionate), N (dinitrogen, ammonium, nitrate and nitrite) and redox active metals (Fe(II) and Mn(II)). Sulfate had the largest effects on the cycling of S and C. All the added S at lower loadings were converted to AVS over the course of the experiment (30 days). At the highest loading (8 mmol) less than 50% of consumed S was converted to AVS, however this is believed to be a kinetic effect. Although sulfate reduction was occurring in sediments with added sulfate, dissolved sulfide concentrations remained low throughout the study. Sulfate addition affected methanogenesis. In the absence of added carbon, addition of sulfate, even at a loading of 1 mmol, resulted in a halving of methane formation. The initial rate of formation of methane was not affected by sulfate if additional carbon was added to the sediment. However, there was evidence for anaerobic methane oxidation in those sediments with added sulfate and carbon, but not in those sediments treated only with carbon. Surprisingly, sulfate addition had little apparent impact on N dynamics; previous studies have shown that sulfide can inhibit denitrification and stimulate dissimilatory nitrate reduction to ammonia. We propose that because most of the reduced sulfur was in particulate form, levels of dissolved sulfide were too low to interfere with the N cycle. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Microbial Sulfate Reduction Potential in Coal-Bearing Sediments Down to ~2.5 km below the Seafloor off Shimokita Peninsula, Japan

PubMed Central

Glombitza, Clemens; Adhikari, Rishi R.; Riedinger, Natascha; Gilhooly, William P.; Hinrichs, Kai-Uwe; Inagaki, Fumio

2016-01-01

Sulfate reduction is the predominant anaerobic microbial process of organic matter mineralization in marine sediments, with recent studies revealing that sulfate reduction not only occurs in sulfate-rich sediments, but even extends to deeper, methanogenic sediments at very low background concentrations of sulfate. Using samples retrieved off the Shimokita Peninsula, Japan, during the Integrated Ocean Drilling Program (IODP) Expedition 337, we measured potential sulfate reduction rates by slurry incubations with 35S-labeled sulfate in deep methanogenic sediments between 1276.75 and 2456.75 meters below the seafloor. Potential sulfate reduction rates were generally extremely low (mostly below 0.1 pmol cm−3 d−1) but showed elevated values (up to 1.8 pmol cm−3 d−1) in a coal-bearing interval (Unit III). A measured increase in hydrogenase activity in the coal-bearing horizons coincided with this local increase in potential sulfate reduction rates. This paired enzymatic response suggests that hydrogen is a potentially important electron donor for sulfate reduction in the deep coalbed biosphere. By contrast, no stimulation of sulfate reduction rates was observed in treatments where methane was added as an electron donor. In the deep coalbeds, small amounts of sulfate might be provided by a cryptic sulfur cycle. The isotopically very heavy pyrites (δ34S = +43‰) found in this horizon is consistent with its formation via microbial sulfate reduction that has been continuously utilizing a small, increasingly 34S-enriched sulfate reservoir over geologic time scales. Although our results do not represent in-situ activity, and the sulfate reducers might only have persisted in a dormant, spore-like state, our findings show that organisms capable of sulfate reduction have survived in deep methanogenic sediments over more than 20 Ma. This highlights the ability of sulfate-reducers to persist over geological timespans even in sulfate-depleted environments. Our study moreover represents the deepest evidence of a potential for sulfate reduction in marine sediments to date. PMID:27761134

Microbial Sulfate Reduction Potential in Coal-Bearing Sediments Down to ~2.5 km below the Seafloor off Shimokita Peninsula, Japan.

PubMed

Glombitza, Clemens; Adhikari, Rishi R; Riedinger, Natascha; Gilhooly, William P; Hinrichs, Kai-Uwe; Inagaki, Fumio

2016-01-01

Sulfate reduction is the predominant anaerobic microbial process of organic matter mineralization in marine sediments, with recent studies revealing that sulfate reduction not only occurs in sulfate-rich sediments, but even extends to deeper, methanogenic sediments at very low background concentrations of sulfate. Using samples retrieved off the Shimokita Peninsula, Japan, during the Integrated Ocean Drilling Program (IODP) Expedition 337, we measured potential sulfate reduction rates by slurry incubations with 35 S-labeled sulfate in deep methanogenic sediments between 1276.75 and 2456.75 meters below the seafloor. Potential sulfate reduction rates were generally extremely low (mostly below 0.1 pmol cm -3 d -1 ) but showed elevated values (up to 1.8 pmol cm -3 d -1 ) in a coal-bearing interval (Unit III). A measured increase in hydrogenase activity in the coal-bearing horizons coincided with this local increase in potential sulfate reduction rates. This paired enzymatic response suggests that hydrogen is a potentially important electron donor for sulfate reduction in the deep coalbed biosphere. By contrast, no stimulation of sulfate reduction rates was observed in treatments where methane was added as an electron donor. In the deep coalbeds, small amounts of sulfate might be provided by a cryptic sulfur cycle. The isotopically very heavy pyrites (δ 34 S = +43‰) found in this horizon is consistent with its formation via microbial sulfate reduction that has been continuously utilizing a small, increasingly 34 S-enriched sulfate reservoir over geologic time scales. Although our results do not represent in-situ activity, and the sulfate reducers might only have persisted in a dormant, spore-like state, our findings show that organisms capable of sulfate reduction have survived in deep methanogenic sediments over more than 20 Ma. This highlights the ability of sulfate-reducers to persist over geological timespans even in sulfate-depleted environments. Our study moreover represents the deepest evidence of a potential for sulfate reduction in marine sediments to date.

Method for stabilizing low-level mixed wastes at room temperature

DOEpatents

Wagh, A.S.; Singh, D.

1997-07-08

A method to stabilize solid and liquid waste at room temperature is provided comprising combining solid waste with a starter oxide to obtain a powder, contacting the powder with an acid solution to create a slurry, said acid solution containing the liquid waste, shaping the now-mixed slurry into a predetermined form, and allowing the now-formed slurry to set. The invention also provides for a method to encapsulate and stabilize waste containing cesium comprising combining the waste with Zr(OH){sub 4} to create a solid-phase mixture, mixing phosphoric acid with the solid-phase mixture to create a slurry, subjecting the slurry to pressure; and allowing the now pressurized slurry to set. Lastly, the invention provides for a method to stabilize liquid waste, comprising supplying a powder containing magnesium, sodium and phosphate in predetermined proportions, mixing said powder with the liquid waste, such as tritium, and allowing the resulting slurry to set. 4 figs.

Method for stabilizing low-level mixed wastes at room temperature

DOEpatents

Wagh, Arun S.; Singh, Dileep

1997-01-01

A method to stabilize solid and liquid waste at room temperature is provided comprising combining solid waste with a starter oxide to obtain a powder, contacting the powder with an acid solution to create a slurry, said acid solution containing the liquid waste, shaping the now-mixed slurry into a predetermined form, and allowing the now-formed slurry to set. The invention also provides for a method to encapsulate and stabilize waste containing cesium comprising combining the waste with Zr(OH).sub.4 to create a solid-phase mixture, mixing phosphoric acid with the solid-phase mixture to create a slurry, subjecting the slurry to pressure; and allowing the now pressurized slurry to set. Lastly, the invention provides for a method to stabilize liquid waste, comprising supplying a powder containing magnesium, sodium and phosphate in predetermined proportions, mixing said powder with the liquid waste, such as tritium, and allowing the resulting slurry to set.

Enhancing protein to extremely high content in photosynthetic bacteria during biogas slurry treatment.

PubMed

Yang, Anqi; Zhang, Guangming; Meng, Fan; Lu, Pei; Wang, Xintian; Peng, Meng

2017-12-01

This work proposed a novel approach to achieve an extremely high protein content in photosynthetic bacteria (PSB) using biogas slurry as a culturing medium. The results showed the protein content of PSB could be enhanced strongly to 90% in the biogas slurry, which was much higher than reported microbial protein contents. The slurry was partially purified at the same time. Dark-aerobic was more beneficial than light-anaerobic condition for protein accumulation. High salinity and high ammonia of the biogas slurry were the main causes for protein enhancement. In addition, the biogas slurry provided a good buffer system for PSB to grow. The biosynthesis mechanism of protein in PSB was explored according to theoretical analysis. During biogas slurry treatment, the activities of glutamate synthase and glutamine synthetase were increased by 26.55%, 46.95% respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental study on the application of paraffin slurry to high density electronic package cooling

NASA Astrophysics Data System (ADS)

Cho, K.; Choi, M.

Experiments were performed by using water and paraffin slurry to investigate thermal characteristics from a test multichip module. The parameters were the mass fraction of paraffin slurry (0, 2.5, 5, 7.5%), heat flux (10, 20, 30, 40W/cm2) and channel Reynolds numbers. The size of paraffin slurry particles was within 10-40μm. The local heat transfer coefficients for the paraffin slurry were larger than those for water. Thermally fully developed conditions were observed after the third or fourth row. The paraffin slurry with a mass fraction of 5% showed the most efficient cooling performance when the heat transfer and the pressure drop in the test section were considered simultaneously. A new correlation for the water and the paraffin slurry with a mass fraction of 5% was obtained for a channel Reynolds number over 5300.

Drilling Holes in Graphite/Epoxy Composites

NASA Technical Reports Server (NTRS)

Daniels, J. G.; Ledbetter, Frank E., III; Penn, B. G.; White, W. L.

1986-01-01

Slurry of silicon carbide powder in water fed onto bit while drilling. Slurry contains about 60 percent silicon carbide by weight. Slurry recirculated by low-power pump. With slurry, dull tools cut as fast as, or faster than, sharp ones. Holes drilled rapidly and efficiently regardless of ply orientation; whether unidirectional, quasi-isotropic symmetrical, or cross-ply.

CATALYTIC RECOMBINATION OF RADIOLYTIC GASES IN THORIUM OXIDE SLURRIES

DOEpatents

Morse, L.E.

1962-08-01

A method for the coinbination of hydrogen and oxygen in aqueous thorium oxide-uranium oxide slurries is described. A small amount of molybdenum oxide catalyst is provided in the slurry. This catalyst is applicable to the recombination of hydrogen and/or deuterium and oxygen produced by irradiation of the slurries in nuclear reactors. (AEC)

Characterization of DWPF recycle condensate tank materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bannochie, C. J.

2015-01-01

A Defense Waste Processing Facility (DWPF) Recycle Condensate Tank (RCT) sample was delivered to the Savannah River National Laboratory (SRNL) for characterization with particular interest in the concentration of I-129, U-233, U-235, total U, and total Pu. Since a portion of Salt Batch 8 will contain DWPF recycle materials, the concentration of I-129 is important to undertand for salt batch planning purposes. The chemical and physical characterizations are also needed as input to the interpretation of future work aimed at determining the propensity of the RCT material to foam, and methods to remediate any foaming potential. According to DWPF themore » Tank Farm 2H evaporator has experienced foaming while processing DWPF recycle materials. The characterization work on the RCT samples has been completed and is reported here. The composition of the Sludge Batch 8 (SB8) RCT material is largely a low base solution of 0.2M NaNO 2 and 0.1M NaNO 3 with a small amount of formate present. Insoluble solids comprise only 0.05 wt.% of the slurry. The solids appear to be largely sludge-like solids based on elemental composition and SEM-EDS analysis. The sample contains an elevated concentration of I-129 (38x) and substantial 59% fraction of Tc-99, as compared to the incoming SB8 Tank 40 feed material. The Hg concentration is 5x, when compared to Fe, of that expected based on sludge carryover. The total U and Pu concentrations are reduced significantly, 0.536 wt.% TS and 2.42E-03 wt.% TS, respectively, with the fissile components, U-233, U-235, Pu-239, and Pu-241, an order of magnitude lower in concentration than those in the SB8 Tank 40 DWPF feed material. This report will be revised to include the foaming study requested in the TTR and outlined in the TTQAP when that work is concluded.« less

Rheological Behavior and Microstructure of Ceramic Particulate/Aluminum Alloy Composites. Ph.D. Thesis Final Technical Report

NASA Technical Reports Server (NTRS)

Moon, Hee-Kyung

1990-01-01

The rheological behavior and microstructure were investigated using a concentric cylinder viscometer for three different slurries: semi-solid alloy slurries of a matrix alloy, Al-6.5wt percent Si: composite slurries, SiC (sub p) (8.5 microns)/Al-6.5wt percent Si, with the same matrix alloy in the molten state, and composite slurries of the same composition with the matrix alloy in the semi-solid state. The pseudoplasticity of these slurries was obtained by step changes of the shear rate from a given initial shear rate. To study the thixotropic behavior of the system, a slurry was allowed to rest for different periods of time, prior to shearing at a given initial shear rate. In the continuous cooling experiments, the viscosities of these slurries were dependent on the shear rate, cooling rate, volume fraction of the primary solid of the matrix alloy, and volume fraction of silicon carbide. In the isothermal experiments, all three kinds of slurries exhibited non-Newtonian behavior, depending on the volume fraction of solid particles.

Interactions between soil texture and placement of dairy slurry application: I. Flow characteristics and leaching of nonreactive components.

PubMed

Glaesner, Nadia; Kjaergaard, Charlotte; Rubaek, Gitte H; Magid, Jakob

2011-01-01

Land application of manure can exacerbate nutrient and contaminant transfers to the aquatic environment. This study examined the effect of injecting a dairy cattle (Bostaurus L.) manure slurry on mobilization and leaching of dissolved, nonreactive slurry components across a range of agricultural soils. We compared leaching of slurry-applied bromide through intact soil columns (20 cm diam., 20 cm high) of differing textures following surface application or injection of slurry. The volumetric fraction of soil pores >30 microm ranged from 43% in a loamy sand to 28% in a sandy loam and 15% in a loam-textured soil. Smaller active flow volumes and higher proportions of preferential flow were observed with increasing soil clay content. Injection of slurry in the loam soil significantly enhanced diffusion of applied bromide into the large fraction of small pores compared with surface application. The resulting physical protection against leaching of bromide was reflected by 60.2% of the bromide tracer was recovered in the effluent after injection, compared with 80.6% recovery after surface application. No effect of slurry injection was observed in the loamy sand and sandy loam soils. Our findings point to soil texture as an important factor influencing leaching of dissolved, nonreactive slurry components in soils amended with manure slurry.

Electrode Slurry Particle Density Mapping Using X-ray Radiography

DOE PAGES

Higa, Kenneth; Zhao, Hui; Parkinson, Dilworth Y.; ...

2017-01-05

The internal structure of a porous electrode strongly influences battery performance. Understanding the dynamics of electrode slurry drying could aid in engineering electrodes with desired properties. For instance, one might monitor the dynamic, spatially-varying thickness near the edge of a slurry coating, as it should lead to non-uniform thickness of the dried film. This work examines the dynamic behavior of drying slurry drops consisting of SiO x and carbon black particles in a solution of carboxymethylcellulose and deionized water, as an experimental model of drying behavior near the edge of a slurry coating. An X-ray radiography-based procedure is developed tomore » calculate the evolving spatial distribution of active material particles from images of the drying slurry drops. To the authors’ knowledge, this study is the first to use radiography to investigate battery slurry drying, as well as the first to determine particle distributions from radiography images of drying suspensions. The dynamic results are consistent with tomography reconstructions of the static, fully-dried films. It is found that active material particles can rapidly become non-uniformly distributed within the drops. Heating can promote distribution uniformity, but seemingly must be applied very soon after slurry deposition. Higher slurry viscosity is found to strongly restrain particle redistribution.« less

Technical Development of Slurry Three-Dimensional Printer

NASA Astrophysics Data System (ADS)

Jiang, Cho-Pei; Hsu, Huang-Jan; Lee, Shyh-Yuan

2017-09-01

The aim of this paper is to review the technical development of slurry three-dimensional printer (3DP) which based on photo-polymerization and constrained surface method. Basically, slurry consists of ceramic powder, resin and photo-initiator. The light engines for solidifying the photo-curable slurry can be classified as laser, liquid crystal panel (LCD), digital light processing (DLP). The slurry can be reacted and solidified by selective ray according to the reaction spectrum of photo-initiator. Ceramic powder used in this study is zirconia oxide. Experimental results show that ceramic particle size affects the viscosity of slurry severely resulting in low accuracy and the occurrence of micro crack in the layer casting procedure. Therefore, the effect of particle size on the curability and accuracy of built green part is discussed. A single dental crown is proposed to be fabricated by these three light engines as a benchmark for comparison. In addition, the cost and the limitation are compared in the aspect of dental crown fabrication. Consequently, the lowest cost is LCD-type slurry 3DP system. DLP-type slurry 3DP can produce green body with the fastest fabrication time. The volumetric error of sintered part that made by these three fabrication methods is similar because the composition of slurry is the same.

Effects of cattle-slurry treatment by acidification and separation on nitrogen dynamics and global warming potential after surface application to an acidic soil.

PubMed

Fangueiro, David; Pereira, José; Bichana, André; Surgy, Sónia; Cabral, Fernanda; Coutinho, João

2015-10-01

Cattle-slurry (liquid manure) application to soil is a common practice to provide nutrients and organic matter for crop growth but it also strongly impacts the environment. The objective of the present study was to assess the efficiency of cattle-slurry treatment by solid-liquid separation and/or acidification on nitrogen dynamics and global warming potential (GWP) following application to an acidic soil. An aerobic laboratory incubation was performed over 92 days with a Dystric Cambisol amended with raw cattle-slurry or separated liquid fraction (LF) treated or not by acidification to pH 5.5 by addition of sulphuric acid. Soil mineral N contents and NH3, N2O, CH4 and CO2 emissions were measured. Results obtained suggest that the acidification of raw cattle-slurry reduced significantly NH3 emissions (-88%) but also the GWP (-28%) while increased the N availability relative to raw cattle-slurry (15% of organic N applied mineralised against negative mineralisation in raw slurry). However, similar NH3 emissions and GWP were observed in acidified LF and non-acidified LF treatments. On the other hand, soil application of acidified cattle-slurry rather than non-acidified LF should be preferred attending the lower costs associated to acidification compared to solid-liquid separation. It can then be concluded that cattle-slurry acidification is a solution to minimise NH3 emissions from amended soil and an efficient strategy to decrease the GWP associated with slurry application to soil. Furthermore, the more intense N mineralisation observed with acidified slurry should lead to a higher amount of plant available N and consequently to higher crop yields. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bed morphological features associated with an optimal slurry concentration for reproducible preparation of efficient capillary ultrahigh pressure liquid chromatography columns.

PubMed

Reising, Arved E; Godinho, Justin M; Jorgenson, James W; Tallarek, Ulrich

2017-06-30

Column wall effects and the formation of larger voids in the bed during column packing are factors limiting the achievement of highly efficient columns. Systematic variation of packing conditions, combined with three-dimensional bed reconstruction and detailed morphological analysis of column beds, provide valuable insights into the packing process. Here, we study a set of sixteen 75μm i.d. fused-silica capillary columns packed with 1.9μm, C18-modified, bridged-ethyl hybrid silica particles slurried in acetone to concentrations ranging from 5 to 200mg/mL. Bed reconstructions for three of these columns (representing low, optimal, and high slurry concentrations), based on confocal laser scanning microscopy, reveal morphological features associated with the implemented slurry concentration, that lead to differences in column efficiency. At a low slurry concentration, the bed microstructure includes systematic radial heterogeneities such as particle size-segregation and local deviations from bulk packing density near the wall. These effects are suppressed (or at least reduced) with higher slurry concentrations. Concomitantly, larger voids (relative to the mean particle diameter) begin to form in the packing and increase in size and number with the slurry concentration. The most efficient columns are packed at slurry concentrations that balance these counteracting effects. Videos are taken at low and high slurry concentration to elucidate the bed formation process. At low slurry concentrations, particles arrive and settle individually, allowing for rearrangements. At high slurry concentrations, they arrive and pack as large patches (reflecting particle aggregation in the slurry). These processes are discussed with respect to column packing, chromatographic performance, and bed microstructure to help reinforce general trends previously described. Conclusions based on this comprehensive analysis guide us towards further improvement of the packing process. Copyright © 2017 Elsevier B.V. All rights reserved.

Geochemical Tracers and Rates of Short-Chain Alkane Production in Gulf of Mexico Cold Seep Sediments

NASA Astrophysics Data System (ADS)

Sibert, R.; Bernard, B. B.; Brooks, J. M.; Hunter, K.; Joye, S. B.

2014-12-01

The organic-rich cold seep sediments in the deep Gulf of Mexico commonly contain mixtures of light hydrocarbon gases either dissolved in pore fluids, adsorbed to sediment particles, trapped in methane ice, or as free gas. The dominant component in these natural gas mixtures is typically methane (C1), but ethane (C2) and propane (C3) are nearly always present in trace or major amounts. The ratio of C1:C2:C3 varies but C2 and C3 are typically present at single digit percent levels, whereas methane usually dominates at >80%. Methane production proceeds by at least two well-studied mechanisms: either 1) by thermocatalytic cracking of fossil organic matter, or 2) as a direct product of microbial metabolism, methanogenesis. In contrast, ethane and propane production in deep-sea sediments has been historically attributed only to thermocatalytic processes. However, limited data suggests production of C2/C3 compounds through the activity of archaea. Such studies of microbial- driven dynamics of C2/C3 gases (i.e. 'alkanogenesis') in cold seep sediments are rare. Furthermore, the identities of potential substrates are poorly constrained and no attempt has been made to quantify production rates of C2/C3 gases. However, carbon isotopic data on ethane and propane from deep cores from the Gulf of Mexico suggest alkanogenesis at depth in the sediment column and alkane oxidation in uppermost oxidant-rich sediments. Here, we present the results of a series of incubation experiments using sediment slurries culled from GC600, one of the most prolific natural oil and gas seeps in the Gulf of Mexico. Rates of both alkane production and oxidation were measured under a variety of conditions to assess the net rates of alkane production and elucidate the driving microbiological mechanisms and controls on the central processes of >C1 alkane cycling in cold seep sediments. Microbial processes are important both in terms of alkane production and oxidation, raising many questions as to the biological production of these gases across the biosphere.

Ice Slurry Ingestion and Physiological Strain During Exercise in Non-Compensable Heat Stress.

PubMed

Ng, Jason; Wingo, Jonathan E; Bishop, Phillip A; Casey, Jason C; Aldrich, Elizabeth K

2018-05-01

Precooling with ice slurry ingestion attenuates the increase in rectal temperature (Tre) during subsequent running and cycling. It remains unclear how this cooling method affects physiological strain during work while wearing protective garments. This study investigated the effect of ice slurry ingestion on physiological strain during work in hot conditions while wearing firefighter protective clothing. In three counterbalanced trials, eight men (mean ± SD; age = 21 ± 2 yr, height = 179.5 ± 3.5 cm, mass = 79.1 ± 4.1 kg, body fat = 11.4 ± 3.7%) wore firefighter protective clothing and walked (4 km · h-1, 12% incline, ∼7 METs) for 30 min in hot conditions (35°C, 40% RH). Every 2.5 min, subjects ingested 1.25 g · kg-1 (relative total: 15 g · kg-1, absolute total: 1186.7 ± 61.3 g) of a tepid (22.4 ± 1.7°C), cold (7.1 ± 1.5°C), or ice slurry (-1.3 ± 0.2°C) beverage. Heart rates (HR) were lower with ice slurry ingestion compared to both fluid trials starting 5 min into exercise (tepid = 158 ± 14, cold = 157 ± 11, ice slurry = 146 ± 13 bpm) and persisting for the remainder of the bout (min 30: tepid = 196 ± 10, cold = 192 ± 10, ice slurry = 181 ± 13 bpm). Tre was lower with ice slurry ingestion compared to cold and tepid trials (min 5: tepid = 37.17 ± 0.38, cold = 37.17 ± 0.39, ice slurry = 37.05 ± 0.43°C; min 30: tepid = 38.15 ± 0.29, cold = 38.31 ± 0.36, ice slurry = 37.95 ± 0.32°C). The physiological strain index (PSI) was lower with ice slurry ingestion compared to fluid trials starting at min 5 (tepid = 3.8 ± 0.7, cold = 3.8 ± 0.6, ice slurry = 3.0 ± 0.5) and remained lower throughout exercise (min 30: tepid = 8.2 ± 0.6, cold = 8.3 ± 0.9, ice slurry = 6.9 ± 1.2). A large quantity of ice slurry ingested under non-compensable heat stress conditions mitigated physiological strain during exercise by blunting the rise in heart rate and rectal temperature.Ng J, Wingo JE, Bishop PA, Casey JC, Aldrich EK. Ice slurry ingestion and physiological strain during exercise in non-compensable heat stress. Aerosp Med Hum Perform. 2018; 89(5):434-441.

Chemical Hydride Slurry for Hydrogen Production and Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

McClaine, Andrew W

2008-09-30

The purpose of this project was to investigate and evaluate the attractiveness of using a magnesium chemical hydride slurry as a hydrogen storage, delivery, and production medium for automobiles. To fully evaluate the potential for magnesium hydride slurry to act as a carrier of hydrogen, potential slurry compositions, potential hydrogen release techniques, and the processes (and their costs) that will be used to recycle the byproducts back to a high hydrogen content slurry were evaluated. A 75% MgH 2 slurry was demonstrated, which was just short of the 76% goal. This slurry is pumpable and storable for months at amore » time at room temperature and pressure conditions and it has the consistency of paint. Two techniques were demonstrated for reacting the slurry with water to release hydrogen. The first technique was a continuous mixing process that was tested for several hours at a time and demonstrated operation without external heat addition. Further work will be required to reduce this design to a reliable, robust system. The second technique was a semi-continuous process. It was demonstrated on a 2 kWh scale. This system operated continuously and reliably for hours at a time, including starts and stops. This process could be readily reduced to practice for commercial applications. The processes and costs associated with recycling the byproducts of the water/slurry reaction were also evaluated. This included recovering and recycling the oils of the slurry, reforming the magnesium hydroxide and magnesium oxide byproduct to magnesium metal, hydriding the magnesium metal with hydrogen to form magnesium hydride, and preparing the slurry. We found that the SOM process, under development by Boston University, offers the lowest cost alternative for producing and recycling the slurry. Using the H2A framework, a total cost of production, delivery, and distribution of $4.50/kg of hydrogen delivered or $4.50/gge was determined. Experiments performed at Boston University have demonstrated the technical viability of the process and have provided data for the cost analyses that have been performed. We also concluded that a carbothermic process could also produce magnesium at acceptable costs. The use of slurry as a medium to carry chemical hydrides has been shown during this project to offer significant advantages for storing, delivering, and distributing hydrogen: • Magnesium hydride slurry is stable for months and pumpable. • The oils of the slurry minimize the contact of oxygen and moisture in the air with the metal hydride in the slurry. Thus reactive chemicals, such as lithium hydride, can be handled safely in the air when encased in the oils of the slurry. • Though magnesium hydride offers an additional safety feature of not reacting readily with water at room temperatures, it does react readily with water at temperatures above the boiling point of water. Thus when hydrogen is needed, the slurry and water are heated until the reaction begins, then the reaction energy provides heat for more slurry and water to be heated. • The reaction system can be relatively small and light and the slurry can be stored in conventional liquid fuel tanks. When transported and stored, the conventional liquid fuel infrastructure can be used. • The particular metal hydride of interest in this project, magnesium hydride, forms benign byproducts, magnesium hydroxide (“Milk of Magnesia”) and magnesium oxide. • We have estimated that a magnesium hydride slurry system (including the mixer device and tanks) could meet the DOE 2010 energy density goals. During the investigation of hydriding techniques, we learned that magnesium hydride in a slurry can also be cycled in a rechargeable fashion. Thus, magnesium hydride slurry can act either as a chemical hydride storage medium or as a rechargeable hydride storage system. Hydrogen can be stored and delivered and then stored again thus significantly reducing the cost of storing and delivering hydrogen. Further evaluation and development of this concept will be performed as follow-on work under another project. However, since the cost of reducing magnesium from magnesium oxide makes up 85% of the cost of the slurry, if hydrogen can be stored many times in the slurry, then the cost of storing hydrogen can be spread over many units of hydrogen and can be significantly reduced from the costs of a chemical hydride system. This may be the most important finding of this project. If the slurry is used to carry a rechargeable hydride, the slurry can be stored in a conventional liquid fuel tank and delivered to a release system as hydrogen is needed. The release system will contain only the hydride needed to produce the hydrogen desired. This is in contrast to conventional designs proposed for other rechargeable hydride systems that store all the hydride in a large and heavy pressure and heat transfer vessel.« less

Evaluation of a laboratory-scale bioreactive in situ sediment cap for the treatment of organic contaminants.

PubMed

Himmelheber, David W; Pennell, Kurt D; Hughes, Joseph B

2011-11-01

The development of bioreactive sediment caps, in which microorganisms capable of contaminant transformation are placed within an in situ cap, provides a potential remedial design that can sustainably treat sediment and groundwater contaminants. The goal of this study was to evaluate the ability and limitations of a mixed, anaerobic dechlorinating consortium to treat chlorinated ethenes within a sand-based cap. Results of batch experiments demonstrate that a tetrachloroethene (PCE)-to-ethene mixed consortium was able to completely dechlorinate dissolved-phase PCE to ethene when supplied only with sediment porewater obtained from a sediment column. To simulate a bioreactive cap, laboratory-scale sand columns inoculated with the mixed culture were placed in series with an upflow sediment column and directly supplied sediment effluent and dissolved-phase chlorinated ethenes. The mixed consortium was not able to sustain dechlorination activity at a retention time of 0.5 days without delivery of amendments to the sediment effluent, evidenced by the loss of cis-1,2-dichloroethene (cis-DCE) dechlorination to vinyl chloride. When soluble electron donor was supplied to the sediment effluent, complete dechlorination of cis-DCE to ethene was observed at retention times of 0.5 days, suggesting that sediment effluent lacked sufficient electron donor to maintain active dechlorination within the sediment cap. Introduction of elevated contaminant concentrations also limited biotransformation performance of the dechlorinating consortium within the cap. These findings indicate that in situ bioreactive capping can be a feasible remedial approach, provided that residence times are adequate and that appropriate levels of electron donor and contaminant exist within the cap. Copyright © 2011 Elsevier Ltd. All rights reserved.

Process to remove actinides from soil using magnetic separation

DOEpatents

Avens, Larry R.; Hill, Dallas D.; Prenger, F. Coyne; Stewart, Walter F.; Tolt, Thomas L.; Worl, Laura A.

1996-01-01

A process of separating actinide-containing components from an admixture including forming a slurry including actinide-containing components within an admixture, said slurry including a dispersion-promoting surfactant, adjusting the pH of the slurry to within a desired range, and, passing said slurry through a pretreated matrix material, said matrix material adapted to generate high magnetic field gradients upon the application of a strong magnetic field exceeding about 0.1 Tesla whereupon a portion of said actinide-containing components are separated from said slurry and remain adhered upon said matrix material is provided.

Method for applying a high-temperature bond coat on a metal substrate, and related compositions and articles

DOEpatents

Hasz, Wayne Charles; Sangeeta, D

2006-04-18

A method for applying a bond coat on a metal-based substrate is described. A slurry which contains braze material and a volatile component is deposited on the substrate. The slurry can also include bond coat material. Alternatively, the bond coat material can be applied afterward, in solid form or in the form of a second slurry. The slurry and bond coat are then dried and fused to the substrate. A repair technique using this slurry is also described, along with related compositions and articles.

Method for applying a high-temperature bond coat on a metal substrate, and related compositions and articles

DOEpatents

Hasz, Wayne Charles; Sangeeta, D

2002-01-01

A method for applying a bond coat on a metal-based substrate is described. A slurry which contains braze material and a volatile component is deposited on the substrate. The slurry can also include bond coat material. Alternatively, the bond coat material can be applied afterward, in solid form or in the form of a second slurry. The slurry and bond coat are then dried and fused to the substrate. A repair technique using this slurry is also described, along with related compositions and articles.

In vitro evaluation of the fermentation properties and potential prebiotic activity of Agave fructans.

PubMed

Gomez, E; Tuohy, K M; Gibson, G R; Klinder, A; Costabile, A

2010-06-01

This study was carried out to evaluate in vitro the fermentation properties and the potential prebiotic activity of Agave-fructans extracted from Agave tequilana (Predilife). Five different commercial prebiotics were compared using 24-h pH-controlled anaerobic batch cultures inoculated with human faecal slurries. Measurement of prebiotic efficacy was obtained by comparing bacterial changes, and the production of short-chain fatty acids (SCFA) was also determined. Effects upon major groups of the microbiota were monitored over 24 h incubations by fluorescence in situ hybridization. SCFA were measured by HPLC. Fermentation of the Agave fructans (Predilife) resulted in a large increase in numbers of bifidobacteria and lactobacilli. Under the in vitro conditions used, this study has shown the differential impact of Predilife on the microbial ecology of the human gut. This is the first study reporting of a potential prebiotic mode of activity for Agave fructans investigated which significantly increased populations of bifidobacteria and lactobacilli compared to cellulose used as a control.

Microchannel Reactor System for Catalytic Hydrogenation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeniyi Lawal; Woo Lee; Ron Besser

2010-12-22

We successfully demonstrated a novel process intensification concept enabled by the development of microchannel reactors, for energy efficient catalytic hydrogenation reactions at moderate temperature, and pressure, and low solvent levels. We designed, fabricated, evaluated, and optimized a laboratory-scale microchannel reactor system for hydrogenation of onitroanisole and a proprietary BMS molecule. In the second phase of the program, as a prelude to full-scale commercialization, we designed and developed a fully-automated skid-mounted multichannel microreactor pilot plant system for multiphase reactions. The system is capable of processing 1 – 10 kg/h of liquid substrate, and an industrially relevant immiscible liquid-liquid was successfully demonstratedmore » on the system. Our microreactor-based pilot plant is one-of-akind. We anticipate that this process intensification concept, if successfully demonstrated, will provide a paradigm-changing basis for replacing existing energy inefficient, cost ineffective, environmentally detrimental slurry semi-batch reactor-based manufacturing practiced in the pharmaceutical and fine chemicals industries.« less

Hydrothermal pretreatment enhanced enzymatic hydrolysis and glucose production from oil palm biomass.

PubMed

Zakaria, Mohd Rafein; Hirata, Satoshi; Hassan, Mohd Ali

2015-01-01

The present works investigate hydrothermal pretreatment of oil palm empty fruit bunch and oil palm frond fiber in a batch tube reactor system with temperature and time range from 170 to 250°C and 10 to 20min, respectively. The behavior of soluble sugars, acids, furans, and phenols dramatically changed over treatment severities as determined by HPLC. The cellulose-rich treated solids were analyzed by SEM, WAXD, and BET surface area. Enzymatic hydrolysis was performed from both pretreated slurries and washed solid, and data obtained suggested that tannic acid derived from lignin degradation was a potential cellulase inhibitor. Both partial removal of hemicellulose and migration of lignin during hydrothermal pretreatment caused structural changes on the cellulose-hemicellulose-lignin matrix, resulting in the opening and expansion of specific surface area and pore volume. The current results provided important factors that maximize conversion of cellulose to glucose from oil palm biomass by hydrothermal process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Integrative approach to produce hydrogen and polyhydroxybutyrate from biowaste using defined bacterial cultures.

PubMed

Patel, Sanjay K S; Kumar, Prasun; Singh, Mamtesh; Lee, Jung-Kul; Kalia, Vipin C

2015-01-01

Biological production of hydrogen (H2) and polyhydroxybutyrate (PHB) from pea-shell slurry (PSS) was investigated using defined mixed culture (MMC4, composed of Enterobacter, Proteus, Bacillus spp.). Under batch culture, 19.0LH2/kg of PSS (total solid, TS, 2%w/v) was evolved. Using effluent from the H2 producing stage, Bacillus cereus EGU43 could produce 12.4% (w/w) PHB. Dilutions of PSS hydrolysate containing glucose (0.5%, w/v) resulted in 45-75LH2/kg TS fed and 19.1% (w/w) of PHB content. Under continuous culture, MMC4 immobilized on coconut coir (CC) lead to an H2 yield of 54L/kg TS fed and a PHB content of 64.7% (w/w). An improvement of 2- and 3.7-fold in H2 and PHB yields were achieved in comparison to control. This integrative approach using defined set of bacterial strains can prove effective in producing biomolecules from biowastes. Copyright © 2014. Published by Elsevier Ltd.

Anaerobic hydrolysis and acidification of organic substrates: determination of anaerobic hydrolytic potential.

PubMed

Rajagopal, Rajinikanth; Béline, Fabrice

2011-05-01

This study aimed to develop a biochemical-test mainly to evaluate the hydrolytic-potential of different substrates and to apply this test to characterize various organic substrates. Outcome of this study can be used for optimization of the WWTPs through enhancement of N/P removal or anaerobic digestion. Out of four series of batch experiments, the first two tests were conducted to determine the optimal operating conditions (test duration, inoculum-ratio etc.) for the hydrolytic-potential test using secondary and synthetically-prepared sludges. Based on the results (generation of CODs, pH and VFA), test duration was fixed between 6 and 7d allowing to attain maximum hydrolysis and to avoid methanogenesis. Effect of inoculum-ratios on acid fermentation of sludge was not significantly noticed. Using this methodology, third and fourth tests were performed to characterize various organic substrates namely secondary, pre-treated sludge, pig and two different cattle slurries. VFA production was shown to be substantially dependent on substrates types. Copyright © 2011 Elsevier Ltd. All rights reserved.

Ultrasonic pretreatment for enhanced saccharification and fermentation of ethanol production from corn

NASA Astrophysics Data System (ADS)

Montalbo-Lomboy, Melissa T.

The 21st Century human lifestyle has become heavily dependent on hydrocarbon inputs. Energy demand and the global warming effects due to the burning of fossil fuels have continued to increase. Rising awareness of the negative environmental and economic impacts of hydrocarbon dependence has led to a resurgence of interest in renewable energy sources such as ethanol. Fuel ethanol is known to be a cleaner and renewable source of energy relative to gasoline. Many studies have agreed that fuel ethanol has reduced greenhouse gas (GHG) emissions and has larger overall energy benefits compared to gasoline. Currently, the majority of the fuel ethanol in the United States is produced from corn using dry-grind milling process. The typical dry-grind ethanol plant incorporates jet cooking using steam to cook the corn slurry as pretreatment for saccharification; an energy intensive step. In aiming to reduce energy usage, this study evaluated the use of ultrasonics as an alternative to jet cooking. Ultrasonic batch experiments were conducted using a Branson 2000 Series bench-scale ultrasonic unit operating at a frequency of 20 kHz and a maximum output of 2.2 kW. Corn slurry was sonicated at varying amplitudes from 192 to 320 mumpeak-to-peak(p-p) for 0-40 seconds. Enzyme stability was investigated by adding enzyme (STARGEN(TM)001) before and after sonication. Scanning electron micrograph (SEM) images and particle size distribution analysis showed a nearly 20-fold size reduction by disintegration of corn particles due to ultrasonication. The results also showed a 30% improvement in sugar release of sonicated samples relative to the control group (untreated). The efficiency exceeded 100% in terms of relative energy gain from the additional sugar released due to ultrasonication compared to the ultrasonic energy applied. Interestingly, enzymatic activity was enhanced when sonicated at low and medium power. This result suggested that ultrasonic energy did not denature the enzymes during pretreatment. Ultrasonication of sugary-2 corn was also investigated in the study. Results similar to those for commodity corn (dent corn) were found, in terms of glucose yield and starch conversion. SEM and polarized-light microscope pictures showed the partial gelatinization of corn slurry due to ultrasound. In the 96-h saccharification time, a model was formulated to fit the sugar release curve. The results have shown 17-21% increase in the extent of sugar production from sonicated samples relative to the control group. Additionally, the reaction rates of the sonicated samples were 2- to 10-fold higher than the reaction rates for the control group. In comparing sugary-2 corn with commodity corn, it was found that sonicated sugary-2 corn saccharified faster than sonicated commodity corn. It is important to note, without ultrasonic treatment, sugary-2 corn released more reducing sugar than commodity corn during saccharification. To further investigate the potential of ultrasonics for scale-up, a continuous flow system was studied. An ultrasonic continuous flow system was tested using Branson's flow-through "donut" horn. The donut horn, which vibrates radially, was placed inside a 5.5 L stainless steel reactor. The amplitude was maintained at 12 mumpp and the feed flow rate was varied from 8-27 L/min (2-7 gal/min) with reactor retention times varying from 12-40 seconds. Samples sonicated in continuous flow system showed lower reducing sugar yield than batch ultrasonication. However, considering the ultrasonic energy density of batch and continuous systems, the continuous systems proved to be more energy efficient in terms of glucose production compared with the batch system. It was also seen that particle size disintegration was proportional to energy density regardless of the type of ultrasonic system used. To compare ultrasonics with jet cooking, fermentation experiments were conducted. There were only marginal differences between jet cooked samples and the sonicated samples in terms of ethanol conversion based on theoretical yield. Furthermore, statistical analysis confirmed that there was no significant difference (p<0.05) in the ethanol yields of the two pretreatment methods. Economic analysis indicated that the capital cost of installing ultrasonics was higher compared to jet cooker equipment. However, due to the energy needs of jet cooking, a typical 189 million liters (50 million gallon) per year ethanol plant ethanol plant would save about 16% in pretreatment cost by using ultrasonics. Based on these results, ultrasonication is a promising pretreatment method in corn ethanol production, as an alternative to jet cooking.

Sulfide and methane production in sewer sediments.

PubMed

Liu, Yiwen; Ni, Bing-Jie; Ganigué, Ramon; Werner, Ursula; Sharma, Keshab R; Yuan, Zhiguo

2015-03-01

Recent studies have demonstrated significant sulfide and methane production by sewer biofilms, particularly in rising mains. Sewer sediments in gravity sewers are also biologically active; however, their contribution to biological transformations in sewers is poorly understood at present. In this study, sediments collected from a gravity sewer were cultivated in a laboratory reactor fed with real wastewater for more than one year to obtain intact sediments. Batch test results show significant sulfide production with an average rate of 9.20 ± 0.39 g S/m(2)·d from the sediments, which is significantly higher than the areal rate of sewer biofilms. In contrast, the average methane production rate is 1.56 ± 0.14 g CH4/m(2)·d at 20 °C, which is comparable to the areal rate of sewer biofilms. These results clearly show that the contributions of sewer sediments to sulfide and methane production cannot be ignored when evaluating sewer emissions. Microsensor and pore water measurements of sulfide, sulfate and methane in the sediments, microbial profiling along the depth of the sediments and mathematical modelling reveal that sulfide production takes place near the sediment surface due to the limited penetration of sulfate. In comparison, methane production occurs in a much deeper zone below the surface likely due to the better penetration of soluble organic carbon. Modelling results illustrate the dependency of sulfide and methane productions on the bulk sulfate and soluble organic carbon concentrations can be well described with half-order kinetics. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adsorption-desorption of oxytetracycline on marine sediments: Kinetics and influencing factors.

PubMed

Li, Jia; Zhang, Hua

2016-12-01

To reveal the kinetics and mechanisms of antibiotic adsorption/desorption processes, batch and stirred flow chamber (SFC) experiments were carried out with oxytetracycline (OTC) on two marine sediments. The OTC adsorption capacities of the marine sediments were relatively weak and related to their organic carbon (OC) and contents of fine particles. Sorption isotherms of OTC on marine sediment can be well described by both the Langmuir and Freundlich models. Langmuir adsorption maxima (q max ) and Freundlich distribution coefficients (K f ) increased with the decrease of salinity and pH, which indicated the importance of variable charged sites on sediment surfaces. A second order kinetic model successfully described adsorption and desorption kinetics of OTC and well reproduced the concentration change during stop-flow. The adsorption kinetic rates (k a ) for OTC under different experimental conditions ranged from 2.00 × 10 -4 to 1.97 × 10 -3  L (mg min) -1 . Results of SFC experiments indicated that diffusive mass transfer was the dominant mechanism of the time-dependent adsorption of OTC and its release from marine sediment was mildly hysteretic. The high desorption percentage (43-75% for LZB and 58-75% for BHB) implied that binding strength of OTC on two marine sediments was weak. In conclusion, marine sediment characteristics and environmental factors such as salinity, pH, and flow rate are critical factors determine extent of OTC sorption on marine sediment and need to be incorporated in modeling fate and transport of OTC in marine environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparisons of coarse and fine versions of two carbons for reducing the bioavailabilities of sediment-bound hydrophobic organic contaminants

USGS Publications Warehouse

Lebo, J.A.; Huckins, J.N.; Petty, J.D.; Cranor, W.L.; Ho, K.T.

2003-01-01

Coarse (whole) and finely ground Ambersorb 1500 and coarse and fine coconut charcoal were compared as to their efficiencies in scavenging organic contaminants desorbed from sediment. Aqueous slurries of a test sediment spiked (1 ppm) with p,p???-DDE (DDE), 2,2???,5,5???-tetrachlorobiphenyl (TCB), naphthalene (NAP), or phenanthrene (PHEN), and containing 1% levels of the test carbons were treated by shaking at 35 ??C while exposed to clusters of low-density polyethylene membrane (detox spiders). Controls consisted of spiked sediments and detox spiders but no added carbon of any kind and thus represented unimpeded bioavailabilities (to the spiders). After the treatments - agitation periods from 2.5 to 60 h, depending on contaminant hydrophobicity - the exposed detox spiders were analyzed. The fine carbon of either type was more effective than its coarser variant in obstructing contaminant bioavailabilities. The finer variants of both carbons obstructed the bioavailabilities of NAP and PHEN equally well as did the coarser variants of both. Whole Ambersorb 1500 and coarse coconut charcoal were similarly ineffective in intercepting TCB and DDE. Ground Ambersorb 1500 obstructed virtually all bioavailability of all four contaminants and was far more effective than fine coconut charcoal in intercepting DDE and TCB. An additional experiment compared the effectiveness of ground Ambersorb 1500 and fine coconut charcoal in obstructing the bioavailabilities from sediment of a broad array of spiked organochlorine pesticides. The performance of ground Ambersorb 1500 was again found to be superior; the bioavailable levels of each of the 27 pesticides were markedly lower in the presence of ground Ambersorb 1500 than in the presence of fine coconut charcoal.

Spatial Abundance, Diversity, and Activity of Ammonia-Oxidizing Bacteria in Coastal Sediments of the Liaohe Estuary.

PubMed

Chang, Yongkai; Fan, Jingfeng; Su, Jie; Ming, Hongxia; Zhao, Wen; Shi, Yan; Ji, Fengyun; Guo, Limei; Zan, Shuaijun; Li, Bochao; Guo, Hao; Guan, Daoming

2017-05-01

Ammonia-oxidizing bacteria (AOB) play an important role in nitrification in estuaries. The aim of this study was to examine the spatial abundance, diversity, and activity of AOB in coastal sediments of the Liaohe Estuary using quantitative PCR, high-throughput sequencing of the amoA gene coding the ammonia monooxygenase enzyme active subunit, and sediment slurry incubation experiments. AOB abundance ranged from 8.54 × 10 4 to 5.85 × 10 6 copies g -1 of wet sediment weight and exhibited an increasing trend from the Liaohe Estuary to the open coastal zone. Potential nitrification rates (PNRs) ranged from 0.1 to 336.8 nmol N g -1 day -1 along the estuary to the coastal zone. Log AOB abundance and PNRs were significantly positively correlated. AOB richness decreased from the estuary to the coastal zone. High-throughput sequencing analysis indicated that the majority of amoA gene sequences fell within the Nitrosomonas and Nitrosomonas-like clade, and only a few sequences were clustered within the Nitrosospira clade. This finding indicates that the Nitrosomonas-related lineage may be more adaptable to the specific conditions in this estuary than the Nitrosospira lineage. Sites with high nitrification rates were located in the southern open region and were dominated by the Nitrosomonas-like lineage, whereas the Nitrosospira lineage was found primarily in the northern estuary mouth sites with low nitrification rates. Thus, nitrification potentials in Liaohe estuarine sediments in the southern open region were greater than those in the northern estuary mouth, and the Nitrosomonas-related lineage might play a more important role than the Nitrosospira lineage in nitrification in this estuary.

Sediment‐associated organic matter sources and sediment oxygen demand in a Special Area of Conservation (SAC): A case study of the River Axe, UK

PubMed Central

Zhang, Y.; McMillan, S.; Dixon, E. R.; Stringfellow, A.; Bateman, S.; Sear, D. A.

2017-01-01

Abstract Oxygen demand in river substrates providing important habitats for the early life stages of aquatic ecology, including lithophilous fish, can arise due to the oxidation of sediment‐associated organic matter. Oxygen depletion associated with this component of river biogeochemical cycling, will, in part, depend on the sources of such material. A reconnaissance survey was therefore undertaken to assess the relative contributions from bed sediment‐associated organic matter sources potentially impacting on the River Axe Special Area of Conservation (SAC), in SW England. Source fingerprinting, including Monte Carlo uncertainty analysis, suggested that the relative frequency‐weighted average median source contributions ranged between 19% (uncertainty range 0–82%) and 64% (uncertainty range 0–99%) for farmyard manures or slurries, 4% (uncertainty range 0–49%) and 35% (uncertainty range 0–100%) for damaged road verges, 2% (uncertainty range 0–100%) and 68% (uncertainty range 0–100%) for decaying instream vegetation, and 2% (full uncertainty range 0–15%) and 6% (uncertainty range 0–48%) for human septic waste. A reconnaissance survey of sediment oxygen demand (SOD) along the channel designated as a SAC yielded a mean SOD5 of 4 mg O2 g−1 dry sediment and a corresponding SOD20 of 7 mg O2 g−1 dry sediment, compared with respective ranges of 1–15 and 2–30 mg O2 g−1 dry sediment, measured by the authors for a range of river types across the UK. The findings of the reconnaissance survey were used in an agency (SW region) catchment appraisal exercise for informing targeted management to help protect the SAC. PMID:29527135

Biological treatment of soils contaminated with hydrophobic organics using slurry- and solid-phase techniques

NASA Astrophysics Data System (ADS)

Cassidy, Daniel H.; Irvine, Robert L.

1995-10-01

Both slurry-phase and solid-phase bioremediation are effective ex situ soil decontamination methods. Slurrying is energy intensive relative to solid-phase treatment, but provides homogenization and uniform nutrient distribution. Limited contaminant bioavailability at concentrations above the required cleanup level reduces biodegradation rates and renders solid phase bioremediation more cost effective than complete treatment in a bio-slurry reactor. Slurrying followed by solid-phase bioremediation combines the advantages and minimizes the weaknesses of each treatment method when used alone. A biological treatment system consisting of slurrying followed by aeration in solid phase bioreactors was developed and tested in the laboratory using a silty clay loam contaminated with diesel fuel. The first set of experiments was designed to determine the impact of the water content and mixing time during slurrying on the rate an extent of contaminant removal in continuously aerated solid phase bioreactors. The second set of experiments compared the volatile and total diesel fuel removal in solid phase bioreactors using periodic and continuous aeration strategies. Results showed that slurrying for 1.5 hours at a water content less than saturation markedly increased the rate and extent of contaminant biodegradation in the solid phase bioreactors compared with soil having no slurry pretreatment. Slurrying the soil at or above its saturation moisture content resulted in lengthy dewatering times which prohibited aeration, thereby delaying the onset of biological treatment in the solid phase bioreactors. Results also showed that properly operated periodic aeration can provide less volatile contaminant removal and a grater fraction of biological contaminant removal than continuous aeration.

Upland and wetland vegetation establishment on coal slurry in northern Missouri

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skeel, V.A.; Nawrot, J.R.

Since the Cooperative Wildlife Research Laboratory`s (CWRL) Mined Land Reclamation Program`s first establishment of a wetland on slurry in 1976, industry, state, and federal agency interest in reclamation alternatives for inactive slurry has increased. CWRL has been involved in pre-reclamation site characterization and monitoring for inactive slurry impoundments throughout Illinois, Indiana, Kansas, Kentucky, Missouri, and Washington. Geochemical site characterization of three slurry impoundments at the AECI Bee Veer Mine located near Macon, Missouri began in April 1990. A substrate sampling grid was established for all slurry impoundments with a centerline orientated parallel to the discharge to decant flow pattern. Surfacemore » (0--6 in.) and subsurface (30--36 in.) slurry samples were collected annually and analyzed for acid-base balance, immediate acidity macro- and micro-nutrients, potential phytotoxic metallic ions and salts, and texture. Water table elevations and water quality were monitored quarterly from shallow ({le}12 ft.) piezometers. General reclamation plans included annual (3 years) incremental limestone amendments (35--50 tons/acre) and direct vegetation establishment. Cool and warm season grasses dominate vegetation cover in upland habitats (slurry cell RDA1) while wetland habitats (palustrine emergent seasonally-permanently inundated) have been established in slurry cells (RDA2 and RDA3). Isolated hot spots continue to be amended with limestone and supplemental vegetation establishment is scheduled.« less

Surface texture and composition of titanium brushed with toothpaste slurries of different pHs.

PubMed

Hossain, Awlad; Okawa, Seigo; Miyakawa, Osamu

2007-02-01

This in vitro study characterized the surface texture and composition of titanium brushed with toothpaste slurries of different pHs, and thereby elucidated mechanochemical interactions between the metal and abrasive material in dentifrice. Two fluoride-free toothpastes, which contained crystalline CaHPO(4).2H(2)O and amorphous SiO(2) particles as abrasive, were mixed with acidic buffers to provide slurries of pH 6.8 and 4.8. Specimens were cast from CP Ti, mirror-polished, and then toothbrushed at 120strokes/min for 350,400 strokes under a load of 2.45N. Specimen surfaces were characterized by means of SPM and EPMA. The obtained data were compared with the already reported results of water-diluted alkaline slurries. SPM data of each paste were analyzed using one-way ANOVA, followed by post hoc Tukey test. Irrespective of toothpaste, neutral slurries, as with alkaline slurries, yielded a chemically altered surface with rough texture, whereas acidic slurries formed a chemically clean surface with relatively smooth texture. Mechanochemical polishing effect might be mainly responsible for the cleanness and smoothness. Acidic slurry-induced smooth surface may minimize plaque formation. However, the augmentation of released titanium ions may be adverse to the human body. For evaluation of toothpaste abrasion effects on titanium, paste slurry pH should be taken into account.

Micro- and Nano-scale Diffusion Domains Acting as Kinetic Controls for U(VI) Release to the Hanford 300-Area Aquifer

NASA Astrophysics Data System (ADS)

Stoliker, D. L.; Hay, M. B.; Davis, J. A.; Zachara, J. M.

2008-12-01

The 300-Area of the Hanford reservation, a cold-war era nuclear processing facility, is plagued by long-term elevated concentrations of U(VI) in the underlying aquifer. While the sediment U(VI) concentration is relatively low, it continues to act as a source and sink for the contaminant, allowing for persistent groundwater concentrations well above the maximum contamination limit (MCL). Simple Kd modeling of the attenuation of U(VI) in the aquifer predicted that groundwater U(VI) concentrations would decrease to below the drinking water standard by the year 2002. However, grain-scale morphology of the aquifer material suggests that intra-grain flow paths and mineral coatings, in which sorption complexes and precipitates formed over years of waste disposal, provide a significant kinetic constraint that slows groundwater flushing of the sediments. In order to quantify the impact of diffusion kinetics on the release of U(VI), high-resolution, non-reactive tracer studies were conducted on vadose zone sediments in both column and batch reactors. Systems were equilibrated for long time scales with tritated artificial groundwater and then flushed with flow and stop-flow events included for columns. Previously collected U(VI) release data from batch dissolution/desorption studies is compared with tritium tracer diffusion kinetics as well as porosimetry and detailed microscopy characterization. The micro-scale and nano-scale diffusion regimes, including intra-granular regions as well as mineral coatings, represent a significant potential long-term source of contaminant U(VI). Understanding the physical kinetic limitations coupled with the complex chemistry of U(VI) sorption processes within natural systems is an important step forward in providing information to strengthen field-scale reactive transport simulations.

Apparatus and method for transferring slurries

DOEpatents

Horton, J.R.

1982-08-13

Slurry is transferred to a high pressure region by pushing the slurry from the bottom of a transfer vessel with a pressurizing liquid admitted into the top of the vessel. While the pressurizing liquid is being introduced into the transfer vessel, pressurizing liquid which has mixed with slurry is drawn off from the transfer vessel at a point between its upper and lower ends.

Apparatus and method for transferring slurries

DOEpatents

Horton, Joel R.

1984-01-01

Slurry is transferred to a high pressure region by pushing the slurry from the bottom of a transfer vessel with a pressurizing liquid admitted into the top of the vessel. While the pressurizing liquid is being introduced into the transfer vessel, pressurizing liquid which has mixed with slurry is drawn off from the transfer vessel at a point between its upper and lower ends.

SEPARATING LIQUID MODERATOR FROM A SLURRY TYPE REACTOR

DOEpatents

Vernon, H.C.

1961-07-01

A system for evaporating moderator such as D/sub 2/O from an irradiated slurry or sloution characterized by two successive evaproators is described. In the first of these the most troublesome radioactivity dissipates before the slurry becomes too thick to be pumped out; in the second the slurry, now easier to handle, can be safely reduced to a sludge.

Supersonic coal water slurry fuel atomizer

DOEpatents

Becker, Frederick E.; Smolensky, Leo A.; Balsavich, John

1991-01-01

A supersonic coal water slurry atomizer utilizing supersonic gas velocities to atomize coal water slurry is provided wherein atomization occurs externally of the atomizer. The atomizer has a central tube defining a coal water slurry passageway surrounded by an annular sleeve defining an annular passageway for gas. A converging/diverging section is provided for accelerating gas in the annular passageway to supersonic velocities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higa, Kenneth; Zhao, Hui; Parkinson, Dilworth Y.

The internal structure of a porous electrode strongly influences battery performance. Understanding the dynamics of electrode slurry drying could aid in engineering electrodes with desired properties. For instance, one might monitor the dynamic, spatially-varying thickness near the edge of a slurry coating, as it should lead to non-uniform thickness of the dried film. This work examines the dynamic behavior of drying slurry drops consisting of SiO x and carbon black particles in a solution of carboxymethylcellulose and deionized water, as an experimental model of drying behavior near the edge of a slurry coating. An X-ray radiography-based procedure is developed tomore » calculate the evolving spatial distribution of active material particles from images of the drying slurry drops. To the authors’ knowledge, this study is the first to use radiography to investigate battery slurry drying, as well as the first to determine particle distributions from radiography images of drying suspensions. The dynamic results are consistent with tomography reconstructions of the static, fully-dried films. It is found that active material particles can rapidly become non-uniformly distributed within the drops. Heating can promote distribution uniformity, but seemingly must be applied very soon after slurry deposition. Higher slurry viscosity is found to strongly restrain particle redistribution.« less

Interactions between phosphorus feeding strategies for pigs and dairy cows and separation efficiency of slurry.

PubMed

Sommer, S G; Maahn, M; Poulsen, H D; Hjorth, M; Sehested, J

2008-01-01

Phosphorus (P) in manure is a nutrient source for plants, but surplus P amended to fields represents a risk to the environment. This study examines the interactions between low-P diets for pigs and dairy cows and the separation of animal slurry into a solid P fraction and a liquid fraction. Replacing inorganic phosphates with phytase in pig feed reduced the concentration of P in slurry by 35%, but supplementing concentrates to dairy cows did not affect the P concentration in cattle slurry. Particle-size fractions of the slurry were not affected by these dietary changes. The amount of dry matter (DM) in the < 0.025 mm fraction was greater in pig slurry than in cattle slurry, but the relative amounts of P and nitrogen (N) were larger in the > 0.025 mm fraction. Replacing feed phosphate, in the form of mono-calcium phosphate, with phytase in the pig diet reduced the separation index (efficiency) of P from 80% to 60%.

The importance of the solids loading on confirming the dielectric nanosize dependence of BaTiO₃ powders by slurry method.

PubMed

Zhou, Wei; Nie, Yi Mei; Li, Shu Jing; Liang, Hai Yan

2013-01-01

The dielectric nanosize dependence of BaTiO₃ powders was investigated by the slurry method, where two series of BaTiO₃ slurries with 10 vol% and 30 vol% solids loadings were prepared as model samples. Applying the Bruggeman-Hanai equation, the high-frequency limiting permittivity (ε(h)) of the slurries was extracted from the dielectric spectra. The ε(h) of the 10 vol% slurry showed abnormal size independence in the range from 100 nm to 700 nm, and the ε(h) of the 30 vol% slurry exhibited good agreement with the previous prediction. Through analysing quantitatively the response of ε(h) to the changing permittivity of the powders under different solids loading, it was found that the ε h of the slurry with lower solids loading is more inclined to be interfered by the systematic and random errors. Furthermore, a high permittivity value was found in the BaTiO₃ powders with 50 nm particle size.

Nitrogen and phosphorus removal coupled with carbohydrate production by five microalgae cultures cultivated in biogas slurry.

PubMed

Tan, Fen; Wang, Zhi; Zhouyang, Siyu; Li, Heng; Xie, Youping; Wang, Yuanpeng; Zheng, Yanmei; Li, Qingbiao

2016-12-01

In this study, five microalgae strains were cultured for their ability to survive in biogas slurry, remove nitrogen resources and accumulate carbohydrates. It was proved that five microalgae strains adapted in biogas slurry well without ammonia inhibition. Among them, Chlorella vulgaris ESP-6 showed the best performance on carbohydrate accumulation, giving the highest carbohydrate content of 61.5% in biogas slurry and the highest ammonia removal efficiency and rate of 96.3% and 91.7mg/L/d respectively in biogas slurry with phosphorus and magnesium added. Additionally, the absence of phosphorus and magnesium that can be adverse for biomass accumulation resulted in earlier timing of carbohydrate accumulation and magnesium was firstly recognized and proved as the influence factor for carbohydrate accumulation. Microalgae that cultured in biogas slurry accumulated more carbohydrate in cell, making biogas slurry more suitable medium for the improvement of carbohydrate content, thus can be regarded as a new strategy to accumulate carbohydrate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Medical ice slurry production device

DOEpatents

Kasza, Kenneth E [Palos Park, IL; Oras, John [Des Plaines, IL; Son, HyunJin [Naperville, IL

2008-06-24

The present invention relates to an apparatus for producing sterile ice slurries for medical cooling applications. The apparatus is capable of producing highly loaded slurries suitable for delivery to targeted internal organs of a patient, such as the brain, heart, lungs, stomach, kidneys, pancreas, and others, through medical size diameter tubing. The ice slurry production apparatus includes a slurry production reservoir adapted to contain a volume of a saline solution. A flexible membrane crystallization surface is provided within the slurry production reservoir. The crystallization surface is chilled to a temperature below a freezing point of the saline solution within the reservoir such that ice particles form on the crystallization surface. A deflector in the form of a reciprocating member is provided for periodically distorting the crystallization surface and dislodging the ice particles which form on the crystallization surface. Using reservoir mixing the slurry is conditioned for easy pumping directly out of the production reservoir via medical tubing or delivery through other means such as squeeze bottles, squeeze bags, hypodermic syringes, manual hand delivery, and the like.

Prognostics of slurry pumps based on a moving-average wear degradation index and a general sequential Monte Carlo method

NASA Astrophysics Data System (ADS)

Wang, Dong; Tse, Peter W.

2015-05-01

Slurry pumps are commonly used in oil-sand mining for pumping mixtures of abrasive liquids and solids. These operations cause constant wear of slurry pump impellers, which results in the breakdown of the slurry pumps. This paper develops a prognostic method for estimating remaining useful life of slurry pump impellers. First, a moving-average wear degradation index is proposed to assess the performance degradation of the slurry pump impeller. Secondly, the state space model of the proposed health index is constructed. A general sequential Monte Carlo method is employed to derive the parameters of the state space model. The remaining useful life of the slurry pump impeller is estimated by extrapolating the established state space model to a specified alert threshold. Data collected from an industrial oil sand pump were used to validate the developed method. The results show that the accuracy of the developed method improves as more data become available.

A low-cost solid–liquid separation process for enzymatically hydrolyzed corn stover slurries

DOE PAGES

Sievers, David A.; Lischeske, James J.; Biddy, Mary J.; ...

2015-07-01

Solid-liquid separation of intermediate process slurries is required in some process configurations for the conversion of lignocellulosic biomass to transportation fuels. Thermochemically pretreated and enzymatically hydrolyzed corn stover slurries have proven difficult to filter due to formation of very low permeability cakes that are rich in lignin. Treatment of two different slurries with polyelectrolyte flocculant was demonstrated to increase mean particle size and filterability. Filtration flux was greatly improved, and thus scaled filter unit capacity was increased approximately 40-fold compared with unflocculated slurry. Although additional costs were accrued using polyelectrolyte, techno-economic analysis revealed that the increase in filter capacity significantlymore » reduced overall production costs. Fuel production cost at 95% sugar recovery was reduced by $1.35 US per gallon gasoline equivalent for dilute-acid pretreated and enzymatically hydrolyzed slurries and $3.40 for slurries produced using an additional alkaline de-acetylation preprocessing step that is even more difficult to natively filter.« less

Apparatus and method for pumping hot, erosive slurry of coal solids in coal derived, water immiscible liquid

DOEpatents

Ackerman, Carl D.

1983-03-29

An apparatus for and method of pumping hot, erosive slurry of coal solids in a coal derived, water immiscible liquid to higher pressure involves the use of a motive fluid which is miscible with the liquid of the slurry. The apparatus includes a pump 12, a remote check valve 14 and a chamber 16 between and in fluid communication with the pump 12 and check valve 14 through conduits 18,20. Pump 12 exerts pressure on the motive fluid and thereby on the slurry through a concentration gradient of coal solids within chamber 16 to alternately discharge slurry under pressure from the outlet port of check valve 14 and draw slurry in through the inlet port of check valve 14.

Slurry-pressing consolidation of silicon nitride

NASA Technical Reports Server (NTRS)

Sanders, William A.; Kiser, James D.; Freedman, Marc R.

1988-01-01

A baseline slurry-pressing method for a silicon nitride material is developed. The Si3N4 composition contained 5.8 wt percent SiO2 and 6.4 wt percent Y2O3. Slurry-pressing variables included volume percent solids, application of ultrasonic energy, and pH. Twenty vol percent slurry-pressed material was approximately 11 percent stronger than both 30 vol percent slurry-pressed and dry-pressed materials. The Student's t-test showed the difference to be significant at the 99 percent confidence level. Twenty volume percent (300 h) slurry-pressed test bars exhibited strengths as high as 980 MPa. Large, columnar beta-Si3N4 grains caused failure in the highest strength specimens. The improved strength correlated with better structural uniformity as determined by radiography, optical microscopy, and image analysis.

Conversion of municipal solid waste to hydrogen

NASA Astrophysics Data System (ADS)

Richardson, J. H.; Rogers, R. S.; Thorsness, C. B.

1995-04-01

LLNL and Texaco are cooperatively developing a physical and chemical treatment method for the conversion of municipal solid waste (MSW) to hydrogen via the steps of hydrothermal pretreatment, gasification and purification. LLNL's focus has been on hydrothermal pretreatment of MSW in order to prepare a slurry of suitable viscosity and heating value to allow efficient and economical gasification and hydrogen production. The project has evolved along 3 parallel paths: laboratory scale experiments, pilot scale processing, and process modeling. Initial laboratory-scale MSW treatment results (e.g., viscosity, slurry solids content) over a range of temperatures and times with newspaper and plastics will be presented. Viscosity measurements have been correlated with results obtained at MRL. A hydrothermal treatment pilot facility has been rented from Texaco and is being reconfigured at LLNL; the status of that facility and plans for initial runs will be described. Several different operational scenarios have been modeled. Steady state processes have been modeled with ASPEN PLUS; consideration of steam injection in a batch mode was handled using continuous process modules. A transient model derived from a general purpose packed bed model is being developed which can examine the aspects of steam heating inside the hydrothermal reactor vessel. These models have been applied to pilot and commercial scale scenarios as a function of MSW input parameters and have been used to outline initial overall economic trends. Part of the modeling, an overview of the MSW gasification process and the modeling of the MSW as a process material, was completed by a DOE SERS (Science and Engineering Research Semester) student. The ultimate programmatic goal is the technical demonstration of the gasification of MSW to hydrogen at the laboratory and pilot scale and the economic analysis of the commercial feasibility of such a process.

Technology development for cobalt F-T catalysts. Quarterly technical progress report number 10, January 1--March 31, 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singleton, A.H.

1995-06-28

The goal of this project is the development of a commercially-viable, cobalt-based Fischer-Tropsch (F-T) catalyst for use in a slurry bubble column reactor. The major objectives of this work are (1) to develop a cobalt-based F-T catalyst with low (< 5%) methane selectivity, (2) to develop a cobalt-based F-T catalyst with water-gas shift activity, and (3) to combine both these improvements into one catalyst. The project consists of five major tasks: catalyst development; catalyst testing; catalyst reproducibility tests; catalyst aging tests; and preliminary design and cost estimate for a demonstrate scale catalyst production facility. Technical accomplishments during this reporting periodmore » include the following. It appears that the higher activity obtained for the catalysts prepared using an organic solution and reduced directly without prior calcination was the result of higher dispersions obtained under such pretreatment. A Ru-promoted Co catalyst on alumina with 30% Co loading exhibited a 4-fold increase in dispersion and a 2-fold increase in activity in the fixed-bed reactor from that obtained with the non-promoted catalyst. Several reactor runs have again focused on pushing conversion to higher levels. The maximum conversion obtained has been 49.7% with 26g catalyst. Further investigations of the effect of reaction temperature on the performance of Co catalysts during F-T synthesis were started using a low activity catalyst and one of the most active catalysts. The three 1 kg catalyst batches prepared by Calsicat for the reproducibility and aging studies were tested in both the fixed-bed and slurry bubble column reactors under the standard reaction conditions. The effects of adding various promoters to some cobalt catalysts have also been addressed. Results are presented and discussed.« less

Process design of SSCF for ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw.

PubMed

Bondesson, Pia-Maria; Galbe, Mats

2016-01-01

Pretreatment is an important step in the production of ethanol from lignocellulosic material. Using acetic acid together with steam pretreatment allows the positive effects of an acid catalyst to be retained, while avoiding the negative environmental effects associated with sulphuric acid. Acetic acid is also formed during the pretreatment and hydrolysis of hemicellulose, and is a known inhibitor that may impair fermentation at high concentrations. The purpose of this study was to improve ethanol production from glucose and xylose in steam-pretreated, acetic-acid-impregnated wheat straw by process design of simultaneous saccharification and co-fermentation (SSCF), using a genetically modified pentose fermenting yeast strain Saccharomyces cerevisiae . Ethanol was produced from glucose and xylose using both the liquid fraction and the whole slurry from pretreated materials. The highest ethanol concentration achieved was 37.5 g/L, corresponding to an overall ethanol yield of 0.32 g/g based on the glucose and xylose available in the pretreated material. To obtain this concentration, a slurry with a water-insoluble solids (WIS) content of 11.7 % was used, using a fed-batch SSCF strategy. A higher overall ethanol yield (0.36 g/g) was obtained at 10 % WIS. Ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw through SSCF with a pentose fermenting S. cerevisiae strain was successfully demonstrated. However, the ethanol concentration was too low and the residence time too long to be suitable for large-scale applications. It is hoped that further process design focusing on the enzymatic conversion of cellulose to glucose will allow the combination of acetic acid pretreatment and co-fermentation of glucose and xylose.

Precipitate hydrolysis process for the removal of organic compounds from nuclear waste slurries

DOEpatents

Doherty, Joseph P.; Marek, James C.

1989-01-01

A process for removing organic compounds from a nuclear waste slurry comprising reacting a mixture of radioactive waste precipitate slurry and an acid in the presence of a catalytically effective amount of a copper (II) catalyst whereby the organic compounds in the precipitate slurry are hydrolyzed to form volatile organic compounds which are separated from the reacting mixture. The resulting waste slurry, containing less than 10 percent of the orginal organic compounds, is subsequently blended with high level radioactive sludge and transferred to a virtrification facility for processing into borosilicate glass for long-term storage.

Effects of dairy slurry on silage fermentation characteristics and nutritive value of alfalfa.

PubMed

Coblentz, W K; Muck, R E; Borchardt, M A; Spencer, S K; Jokela, W E; Bertram, M G; Coffey, K P

2014-11-01

Dairy producers frequently ask questions about the risks associated with applying dairy slurry to growing alfalfa (Medicago sativa L.). Our objectives were to determine the effects of applying dairy slurry on the subsequent nutritive value and fermentation characteristics of alfalfa balage. Dairy slurry was applied to 0.17-ha plots of alfalfa; applications were made to the second (HARV1) and third (HARV2) cuttings during June and July of 2012, respectively, at mean rates of 42,400 ± 5271 and 41,700 ± 2397 L/ha, respectively. Application strategies included (1) no slurry, (2) slurry applied directly to stubble immediately after the preceding harvest, (3) slurry applied after 1 wk of post-ensiled regrowth, or (4) slurry applied after 2 wk of regrowth. All harvested forage was packaged in large, rectangular bales that were ensiled as wrapped balage. Yields of DM harvested from HARV1 (2,477 kg/ha) and HARV2 (781 kg/ha) were not affected by slurry application treatment. By May 2013, all silages appeared to be well preserved, with no indication of undesirable odors characteristic of clostridial fermentations. Clostridium tyrobutyricum, which is known to negatively affect cheese production, was not detected in any forage on either a pre- or post-ensiled basis. On a pre-ensiled basis, counts for Clostridium cluster 1 were greater for slurry-applied plots than for those receiving no slurry, and this response was consistent for HARV1 (4.44 vs. 3.29 log10 genomic copies/g) and HARV2 (4.99 vs. 3.88 log10 genomic copies/g). Similar responses were observed on a post-ensiled basis; however, post-ensiled counts also were greater for HARV1 (5.51 vs. 5.17 log10 genomic copies/g) and HARV2 (5.84 vs. 5.28 log10 genomic copies/g) when slurry was applied to regrowth compared with stubble. For HARV2, counts also were greater following a 2-wk application delay compared with a 1-wk delay (6.23 vs. 5.45 log10 genomic copies/g). These results suggest that the risk of clostridial fermentations in alfalfa silages is greater following applications of slurry. Based on pre- and post-ensiled clostridial counts, applications of dairy slurry on stubble are preferred (and less risky) compared with delayed applications on growing alfalfa. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

A Low Salinity Mystery in a Turbidity Current Measured During the Monterey Coordinated Canyon Experiment

NASA Astrophysics Data System (ADS)

Xu, J.; Wang, Z.; Wang, C.; Li, J.; Gwiazda, R.; Paull, C. K.; Maier, K. L.

2016-12-01

Conductivity-Temperature (CT) sensors are one of the most common instruments in oceanographic research that record water conductivity and temperature, two most important parameters of ocean waters from which salinity is computed. When used in super-high turbid water or flows (e.g. turbidity currents or slurries), however, the working principle of CT sensors suggests possibility of bias in conductivity measurements. In this study, a series of lab experiments were conducted to investigate how the presence of high-concentrated sediment particles influences the conductivity readings from an inductive CT sensor. The results provided evidence to challenge a long-held notion that the reduced conductivity often seen inside turbidity currents is an indication of fresh water presence.

Liver histological changes and lipid peroxidation in the amphibian Ambystoma mexicanum induced by sediment elutriates from the Lake Xochimilco.

PubMed

Ortiz-Ordoñez, Esperanza; López-López, Eugenia; Sedeño-Díaz, Jacinto Elías; Uría, Esther; Morales, Ignacio Andrés; Pérez, María Estela; Shibayama, Mineko

2016-08-01

Lacustrine sediments accumulate pollutants that input from the lake watershed and can be released to the water column by sediment resuspension; thus, pollutants can change their bioavailability and exert adverse effects to aquatic biota. Shallow-urban lakes are particularly susceptible to receive pollutants from urban discharges and sediment resuspension. Lake Xochimilco, in Mexico City, an urban-shallow lake, faces multiple problems: urban sprawl, overexploitation of aquifers, drying of springs, discharge of wastewater from treatment plants, and sediment resuspension. The aquatic biota living in this ecosystem is continuously exposed to the release of pollutants from the sediments. We assessed the risk that pollutants released from sediments from Lake Xochimilco, Touristic (TZ) and Agriculture zone (AZ), can exert on a native amphibian species of the lake (Ambystoma mexicanum) through exposure bioassays to sediment elutriates. We evaluate alterations in the amphibian by three approaches: biochemical (level of lipid peroxidation, LPO), cellular (ultrastructure) and the liver histology of A. mexicanum and we compare them with a batch control. Additionally, we assessed heavy metals (Pb, Cd and Hg) in elutriates. Elutriates from TZ showed the highest concentrations of the metals assessed. Organisms exposed to sediment elutriates from either study sites showed higher LPO values than control organisms (p<0.05). Organisms exposed to elutriates from the TZ showed the most conspicuous damages: hepatic vasodilation of sinusoids, capillaries with erythrocytes, leukocyte infiltration and cytoplasmic vacuolation in hepatocytes. The biological responses assessed reflected the risk that faces A. mexicanum when is exposed for prolonged periods to sediment resuspension in Lake Xochimilco. Copyright © 2016. Published by Elsevier B.V.

Identifying and Quantifying Chemical Forms of Sediment-Bound Ferrous Iron.

NASA Astrophysics Data System (ADS)

Kohler, M.; Kent, D. B.; Bekins, B. A.; Cozzarelli, I.; Ng, G. H. C.

2015-12-01

Aqueous Fe(II) produced by dissimilatory iron reduction comprises only a small fraction of total biogenic Fe(II) within an aquifer. Most biogenic Fe(II) is bound to sediments on ion exchange sites; as surface complexes and, possibly, surface precipitates; or incorporated into solid phases (e.g., siderite, magnetite). Different chemical forms of sediment-bound Fe(II) have different reactivities (e.g., with dissolved oxygen) and their formation or destruction by sorption/desorption and precipitation/dissolution is coupled to different solutes (e.g., major cations, H+, carbonate). We are quantifying chemical forms of sediment-bound Fe(II) using previously published extractions, novel extractions, and experimental studies (e.g., Fe isotopic exchange). Sediments are from Bemidji, Minnesota, where biodegradation of hydrocarbons from a burst oil pipeline has driven extensive dissimilatory Fe(III) reduction, and sites potentially impacted by unconventional oil and gas development. Generally, minimal Fe(II) was mobilized from ion exchange sites (batch desorption with MgCl2 and repeated desorption with NH4Cl). A < 2mm sediment fraction from the iron-reducing zone at Bemidji had 1.8umol/g Fe(II) as surface complexes or carbonate phases (sodium acetate at pH 5) of which ca. 13% was present as surface complexes (FerroZine extractions). Total bioavailable Fe(III) and biogenic Fe(II) (HCl extractions) was 40-50 umole/g on both background and iron-reducing zone sediments . Approximately half of the HCl-extractable Fe from Fe-reducing zone sediments was Fe(II) whereas 12 - 15% of Fe extracted from background sediments was present as Fe(II). One-third to one-half of the total biogenic Fe(II) extracted from sediments collected from a Montana prairie pothole located downgradient from a produced-water disposal pit was present as surface-complexed Fe(II).

The new idea of transporting tailings-logs in tailings slurry pipeline and the innovation of technology of mining waste-fill method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin Yu; Wang Fuji; Tao Yan

2000-07-01

This paper introduced a new idea of transporting mine tailings-logs in mine tailings-slurry pipeline and a new technology of mine cemented filing of tailings-logs with tailings-slurry. The hydraulic principles, the compaction of tailings-logs and the mechanic function of fillbody of tailings-logs cemented by tailings-slurry have been discussed.

Methods to enhance the characteristics of hydrothermally prepared slurry fuels

DOEpatents

Anderson, Chris M.; Musich, Mark A.; Mann, Michael D.; DeWall, Raymond A.; Richter, John J.; Potas, Todd A.; Willson, Warrack G.

2000-01-01

Methods for enhancing the flow behavior and stability of hydrothermally treated slurry fuels. A mechanical high-shear dispersion and homogenization device is used to shear the slurry fuel. Other improvements include blending the carbonaceous material with a form of coal to reduce or eliminate the flocculation of the slurry, and maintaining the temperature of the hydrothermal treatment between approximately 300.degree. to 350.degree. C.

Method for enhanced atomization of liquids

DOEpatents

Thompson, Richard E.; White, Jerome R.

1993-01-01

In a process for atomizing a slurry or liquid process stream in which a slurry or liquid is passed through a nozzle to provide a primary atomized process stream, an improvement which comprises subjecting the liquid or slurry process stream to microwave energy as the liquid or slurry process stream exits the nozzle, wherein sufficient microwave heating is provided to flash vaporize the primary atomized process stream.

Impacts of zeolite, alum and polyaluminum chloride amendments mixed with agricultural wastes on soil column leachate, and CO2 and CH4 emissions.

PubMed

Murnane, J G; Fenton, O; Healy, M G

2018-01-15

This study aimed to quantify leaching losses of nitrogen (N), phosphorus (P) and carbon (C), as well as carbon dioxide (CO 2 ) and methane (CH 4 ) emissions from stored slurry, and from packed soil columns surface applied with unamended and chemically amended dairy and pig slurries, and dairy soiled water (DSW). The amendments to the slurries, which were applied individually and together, were: polyaluminum chloride (PAC) and zeolite for pig and dairy slurry, and liquid aluminium sulfate (alum) and zeolite for DSW. Application of pig slurry resulted in the highest total nitrogen (TN) and nitrate-nitrogen (NO 3 -N) fluxes (22 and 12 kg ha -1 ), whereas corresponding fluxes from dairy slurries and DSW were not significantly (p < 0.05) higher than those from the control soil. There were no significant (p < 0.05) differences in leachate N losses between unamended and amended dairy slurries, unamended and amended pig slurries, and unamended and amended DSW. There were no leachate P losses measured over the experimental duration. Total cumulative organic (TOC) and inorganic C (TIC) losses in leachate were highest for unamended dairy slurry (82 and 142 kg ha -1 ), and these were significantly (p < 0.05) reduced when amended with PAC (38 and 104 kg ha -1 ). The highest average cumulative CO 2 emissions for all treatments were measured for pig slurries (680 kg CO 2 -C ha -1 ) followed by DSW (515 kg CO 2 -C ha -1 ) and dairy slurries (486 kg CO 2 -C ha -1 ). The results indicate that pig slurry, either in raw or chemically amended form, poses the greatest environmental threat of leaching losses and gaseous emissions of CO 2 and CH 4 and, in general, amendment of wastewater with PAC, alum or zeolite, does not mitigate the risk of these losses. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Impact of Using Alternative Forages on the Nutrient Value within Slurry and Its Implications for Forage Productivity in Agricultural Systems

PubMed Central

Crotty, Felicity V.; Fychan, Rhun; Theobald, Vince J.; Sanderson, Ruth; Chadwick, David R.; Marley, Christina L.

2014-01-01

Alternative forages can be used to provide valuable home-grown feed for ruminant livestock. Utilising these different forages could affect the manure value and the implications of incorporating these forages into farming systems, needs to be better understood. An experiment tested the hypothesis that applying slurries from ruminants, fed ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or kale (Brassica oleracea) would improve the yield of hybrid ryegrass (Lolium hybridicum), compared with applying slurries from ruminants fed ensiled hybrid ryegrass, or applying inorganic N alone. Slurries from sheep offered one of four silages were applied to ryegrass plots (at 35 t ha−1) with 100 kg N ha−1 inorganic fertiliser; dry matter (DM) yield was compared to plots only receiving ammonium nitrate at rates of 0, 100 and 250 kg N ha−1 year−1. The DM yield of plots treated with 250 kg N, lucerne or red clover slurry was significantly higher than other treatments (P<0.001). The estimated relative fertiliser N equivalence (FNE) (fertiliser-N needed to produce same yield as slurry N), was greatest for lucerne (114 kg) >red clover (81 kg) >kale (44 kg) >ryegrass (26 kg ha−1 yr−1). These FNE values represent relative efficiencies of 22% (ryegrass), 52% (kale), 47% (red clover) and 60% for lucerne slurry, with the ryegrass slurry efficiency being lowest (P = 0.005). Soil magnesium levels in plots treated with legume slurry were higher than other treatments (P<0.001). Overall, slurries from ruminants fed alternative ensiled forages increased soil nutrient status, forage productivity and better N efficiency than slurries from ruminants fed ryegrass silage. The efficiency of fertiliser use is one of the major factors influencing the sustainability of farming systems, these findings highlight the cascade in benefits from feeding ruminants alternative forages, and the need to ensure their value is effectively captured to reduce environmental risks. PMID:24830777

Modelling ammonia volatilization from animal slurry applied with trail hoses to cereals

NASA Astrophysics Data System (ADS)

Sommer, S. G.; Olesen, J. E.

In Europe ammonia (NH 3), volatilization from animal manure is the major source of NH 3 in the atmosphere. From March to July 1997, NH 3 volatilization from trail hose applied slurry was measured for seven days after application in six experiments. A statistical analysis of data showed that NH 3 volatilization rate during the first 4-5 h after slurry application increased significantly ( P<5%) with wind speed and soil slurry surface water content. NH 3 volatilization in the six measuring periods during the experiments increased significantly ( P<5%) with relative water content of the soil slurry surface, global radiation, pH, and decreased with increasing rainfall during each measuring period and rainfall accumulated from onset of each experiment. A mechanistic model of NH 3 volatilization was developed. Model inputs are climate variables, soil characteristics and total ammoniacal nitrogen (TAN=ammonium+ammonia) in the soil surface layer. A pH submodel for predicting pH at the surface of the soil slurry liquid was developed. The measured NH 3 volatilization was compared with model simulations. The simulated results explained 27% of the variation in measured NH 3 volatilization rates during all seven days, but 48% of measured volatilization rates during the first 24 h. Calculations with the model showed that applying slurry in the morning or in the afternoon reduced volatilization by 50% compared with a noon application. Spreading the slurry with trail hoses to a 60 cm high crop reduced losses by 75% compared with a spreading onto bare soil. Ammonia volatilization was 50% lower when the soil had dried out after slurry application compared with a wet slurry surface.

Oxidative degradation and toxicity reduction of trichloroethylene (TCE) in water using TiO2/solar light: comparative study of TiO2 slurry and immobilized systems.

PubMed

Cho, Il-Hyoung; Park, Jae-Hong; Kim, Young-Gyu

2005-01-01

A solar-driven, photocatalyzed degradation system using TiO2 slurry and immobilized systems was constructed and applied to the degradation of trichloroethylene (TCE) contaminated water using TiO2 with solar light. The experiments were carried out under constant weather conditions on a sunny day. Solar photocatalytic treatment efficiency of the solar light/TiO2 slurry system was compared with that of the solar light/TiO2 immobilized system. The operation of the solar light/TiO2 slurry and immobilized systems showed 100% (TiO2 slurry system), 80% (TiO2 immobilized system) degradation of the TCE after 6 h, with a chloride production yield of approximately 89% (TiO2 slurry system), 72% (TiO2 immobilized system). The oxidants such as H2O2 and S2O8(2-) in the TiO2 slurry and immobilized systems increased TCE degradation rate by suppressing the electron/hole recombination process. The degradation rate and relative toxicity reduction of TCE followed the order of solar light/TiO2 slurry + S2O8(2-) > solar light/TiO2 slurry + H2O2 > solar light/TiO2 immobilized + S2O8(2-) > solar light/TiO2 slurry > solar light/TiO2 immobilized + H2O2 > solar light/TiO2 immobilized. Finally, following to the toxicity result, the acute toxicity was reduced by below toxicity endpoint (EC50 concentration) following the treatment. It means that many of the metabolites of TCE reduction are less toxic to Vibrio fischeri than the parent compound. Based on these results, TCE can be efficiently and safely treated in a solar-driven, photocatalyzed degradation system.

Management factors affecting ammonia volatilization from land-applied cattle slurry in the Mid-Atlantic USA.

PubMed

Thompson, R B; Meisinger, J J

2002-01-01

Ammonia (NH3) volatilization commonly causes a substantial loss of crop-available N from surface-applied cattle slurry. Field studies were conducted with small wind tunnels to assess the effect of management factors on NH3 volatilization. Two studies compared NH3 volatilization from grass sward and bare soil. The average total NH3 loss was 1.5 times greater from slurry applied to grass sward. Two studies examined the effect of slurry dry matter (DM) content on NH3 loss under hot, summer conditions in Maryland, USA. Slurry DM contents were between 54 and 134 g kg(-1). Dry matter content did not affect total NH3 loss, but did influence the time course of NH3 loss. Higher DM content slurries had relatively higher rates of NH3 volatilization during the first 12 to 24 h, but lower rates thereafter. Under the hot conditions, the higher DM content slurries appeared to dry and crust more rapidly causing smaller rates of NH3 volatilization after 12 to 24 h, which offset the earlier positive effects of DM content on NH3 volatilization. Three studies compared immediate incorporation with different tillage implements. Total NH3 loss from unincorporated slurry was 45% of applied slurry NH4+-N, while losses following immediate incorporation with a moldboard plow, tandem-disk harrow, or chisel plow were, respectively, 0 to 3, 2 to 8, and 8 to 12%. These ground cover and DM content data can be used to improve predictions of NH3 loss under specific farming conditions. The immediate incorporation data demonstrate management practices that can reduce NH3 volatilization, which can improve slurry N utilization in crop-forage production.

Nitrogen and phosphorus treatment of marine wastewater by a laboratory-scale sequencing batch reactor with eco-friendly marine high-efficiency sediment.

PubMed

Cho, Seonghyeon; Kim, Jinsoo; Kim, Sungchul; Lee, Sang-Seob

2017-06-22

We screened and identified a NH 3 -N-removing bacterial strain, Bacillus sp. KGN1, and a [Formula: see text] removing strain, Vibrio sp. KGP1, from 960 indigenous marine isolates from seawater and marine sediment from Tongyeong, South Korea. We developed eco-friendly high-efficiency marine sludge (eco-HEMS), and inoculated these marine bacterial strains into the marine sediment. A laboratory-scale sequencing batch reactor (SBR) system using the eco-HEMS for marine wastewater from land-based fish farms improved the treatment performance as indicated by 88.2% removal efficiency (RE) of total nitrogen (initial: 5.6 mg/L) and 90.6% RE of total phosphorus (initial: 1.2 mg/L) under the optimal operation conditions (food and microorganism (F/M) ratio, 0.35 g SCOD Cr /g mixed liquor volatile suspended solids (MLVSS)·d; dissolved oxygen (DO) 1.0 ± 0.2 mg/L; hydraulic retention time (HRT), 6.6 h; solids retention time (SRT), 12 d). The following kinetic parameters were obtained: cell yield (Y), 0.29 g MLVSS/g SCOD Cr ; specific growth rate (µ), 0.06 d -1 ; specific nitrification rate (SNR), 0.49 mg NH 3 -N/g MLVSS·h; specific denitrification rate (SDNR), 0.005 mg [Formula: see text]/g MLVSS·h; specific phosphorus uptake rate (SPUR), 0.12 mg [Formula: see text]/g MLVSS·h. The nitrogen- and phosphorus-removing bacterial strains comprised 18.4% of distribution rate in the microbial community of eco-HEMS under the optimal operation conditions. Therefore, eco-HEMS effectively removed nitrogen and phosphorus from highly saline marine wastewater from land-based fish farms with improving SNR, SDNR, and SPUR values in more diverse microbial communities. DO: dissolved oxygen; Eco-HEMS: eco-friendly high efficiency marine sludge; F/M: food and microorganism ratio; HRT: hydraulic retention time; ML(V)SS: mixed liquor (volatile) suspended solids; NCBI: National Center for Biotechnology Information; ND: not determined; qPCR: quantitative real-time polymerase chain reaction; RE: removal efficiency; SBR: sequencing batch reactor; SD: standard deviation; SDNR: specific denitrification rate; SNR: specific nitrification rate; SPUR: specific phosphate uptake rate; SRT: solids retention time; T-N: total nitrogen; T-P: total phosphorus; (V)SS: (volatile) suspended solids; w.w.: wet weight.

Retention and Migration of Chlorpyrifos in Aquatic Sediments and Soils

NASA Astrophysics Data System (ADS)

Gebremariam, S. Y.; Beutel, M.; Yonge, D.; Flury, M.; Harsh, J. B.

2010-12-01

The accurate description of the fate and transport of potentially toxic agricultural pesticides in sediments and soils is of great interest to environmental scientists and regulators. Of particular concern is the widely documented detection of agricultural pesticides and their byproducts in drinking water wells. This presentation discusses results of a study of the fate and transport of chlorpyrifos, a strongly hydrophobic organophosphate-pesticide, in sediments and soils collected from a range of aquatic environments. Using radio-labeled chlorpyrifos, this study is unique in its comprehensive nature and focus on aquatic sediments, for which studies involving pesticide fate and transport are limited. Study components include: (1) batch equilibrium experiments to evaluate sorption/desorption parameters; (2) kinetic and non-equilibrium sorption experiments using miniaturized flow-cells; (3) column experiments to understand patterns of pesticide break through; and (4) numerical modeling of chlorpyrifos transport through aquatic sediments and soils. Initial results show that chlorpyrifos sorption, when corrected for reversible sorption to container walls, exhibited two component sorption, a large irreversible fraction and a smaller reversible fraction that can act as a secondary source. In addition, of a wide range of soil parameters measured, organic carbon content exhibited the highest correlation with chlorpyrifos retention in cranberry field soils. Simulation models developed in this study, which account for hysteretic and nonlinear sorption, will help to better predict the fate of chlorpyrifos and other hydrophobic chemicals in sediments and soils.

Sorption of selected pharmaceuticals and pesticides on different river sediments.

PubMed

Radović, Tanja T; Grujić, Svetlana D; Kovačević, Srđan R; Laušević, Mila D; Dimkić, Milan A

2016-12-01

In the present work, the sorption ability of 17 pharmaceutical compounds, two metabolites, and 15 pesticides (34 target compounds in total) onto four different river sediments was investigated separately. Selected compounds present the most frequently prescribed pharmaceuticals in human and animal medicine and the most frequently used pesticides in agriculture. Their presence into the surface, ground, and waste waters was confirmed into the numerous papers in literature, as well as their presence into the river sediments (for some of them). However, investigations of their sorption onto the river sediments, as major natural protection from potential pollution of ground water by them is missing. Sorption in this study was investigated onto river sediments taken from rivers in the Republic of Serbia, where only less than 10 % of total generated waste water passes through mainly basic treatment processes. Experiments were based on batch equilibrium procedures and obtained solutions were analyzed by previously developed and validated sensitive high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analytical methods. All results were modeled by Freundlich isotherms. Obtained results have shown that Kf coefficient values are in correlation with organic carbon content. Kd sorption coefficient values were relatively low and ranged in wide ranges for almost all compounds and sediments. That implicates on the conclusion that capacities of the investigated sorbents are not large for those compounds.

Slurry burner for mixture of carbonaceous material and water

DOEpatents

Nodd, Dennis G.; Walker, Richard J.

1987-01-01

A carbonaceous material-water slurry burner includes a high pressure tip-emulsion atomizer for directing a carbonaceous material-water slurry into a combustion chamber for burning therein without requiring a support fuel or oxygen enrichment of the combustion air. Introduction of the carbonaceous material-water slurry under pressure forces it through a fixed atomizer wherein the slurry is reduced to small droplets by mixing with an atomizing air flow and directed into the combustion chamber. The atomizer includes a swirler located immediately adjacent to where the fuel slurry is introduced into the combustion chamber and which has a single center channel through which the carbonaceous material-water slurry flows into a plurality of diverging channels continuous with the center channel from which the slurry exits the swirler immediately adjacent to an aperture in the combustion chamber. The swirler includes a plurality of slots around its periphery extending the length thereof through which the atomizing air flows and by means of which the atomizing air is deflected so as to exert a maximum shear force upon the carbonaceous material-water slurry as it exits the swirler and enters the combustion chamber. A circulating coolant system or boiler feed water is provided around the periphery of the burner along the length thereof to regulate burner operating temperature, eliminate atomizer plugging, and inhibit the generation of sparklers, thus increasing combustion efficiency. A secondary air source directs heated air into the combustion chamber to promote recirculation of the hot combustion gases within the combustion chamber.

Gaseous nitrogen and bacterial responses to raw and digested dairy manure applications in incubated soil.

PubMed

Saunders, Olivia E; Fortuna, Ann-Marie; Harrison, Joe H; Cogger, Craig G; Whitefield, Elizabeth; Green, Tonia

2012-11-06

A study was conducted under laboratory conditions to compare rates of nitrous oxide (N(2)O) and ammonia (NH(3)) emissions when soil was amended with anaerobically digested dairy manure slurry containing <30% food byproducts, raw dairy manure slurry, or urea. Slurries were applied via surface and subsurface methods. A second objective was to correlate genes regulating nitrification and denitrification with rates of N(2)O production, slurry treatment, and application method. Ammonia volatilization from incubated soil ranged from 140 g kg(-1) of total N applied in digested slurry to 230 g kg(-1) in urea. Subsurface application of raw dairy manure slurry decreased ammonia volatilization compared with surface application. Anaerobic digestion increased N(2)O production. Cumulative N(2)O loss averaged 27 g kg(-1) of total N applied for digested slurry, compared with 5 g kg(-1) for raw dairy slurry. Genes of interest included a 16S rRNA gene selective for β-subgroup proteobacterial ammonia-oxidizers, amoA, narG, and nosZ quantified with quantitative polymerase chain reaction (qPCR) and real-time polymerase chain reaction (RT-PCR). Application of anaerobically digested slurry increased nitrifier and denitrifier gene copies that correlated with N(2)O production. Expression of all genes measured via mRNA levels was affected by N applications to soil. This study provides new information linking genetic markers in denitrifier and nitrifier populations to N(2)O production.

Effects of soil structure destruction on methane production and carbon partitioning between methanogenic pathways in tropical rain forest soils

NASA Astrophysics Data System (ADS)

Teh, Yit Arn; Silver, Whendee L.

2006-03-01

Controls on methanogenesis are often determined from laboratory incubations of soils converted to slurries. Destruction of soil structure during slurry conversion may disrupt syntrophic associations, kill methanogens, and/or alter the microsite distribution of methanogenic activity, suppressing CH4 production. The effects of slurry conversion on methanogenesis were investigated to determine if disruption of aggregate structure impacted methanogenesis, substrate utilization, and C partitioning between methanogenic pathways. Soils were collected from the tropical rain forest life zone of the Luquillo Experimental Forest, Puerto Rico, and exposed to different physical disturbances, including flooding and physical homogenization. Slurry conversion negatively impacted methanogenesis. Rates of CH4 production declined by a factor of 17 after well-aggregated soils were converted to slurries. Significantly more 13C-acetate was recovered in CO2 compared to CH4 after slurry conversion, suggesting that methanogens consumed less acetate after slurry conversion and may have competed less effectively with other anaerobes for acetate. Isotopic data indicate that the relative partitioning of C between aceticlastic and hydrogenotrophic pathways was unchanged after slurry conversion. These data suggest that experiments which destroy soil structure may significantly underestimate methanogenesis and overestimate the potential for other microorganisms to compete with methanogens for organic substrates. Current knowledge of the factors that regulate methanogenesis in soil may be biased by the findings of slurry-based experiments, that do not accurately represent the complex, spatially heterogeneous conditions found in well-aggregated soils.

Redox Control and Hydrogen Production in Sediment Caps Using Carbon Cloth Electrodes

PubMed Central

Sun, Mei; Yan, Fei; Zhang, Ruiling; Reible, Danny D.; Lowry, Gregory V.; Gregory, Kelvin B.

2010-01-01

Sediment caps that degrade contaminants can improve their ability to contain contaminants relative to sand and sorbent-amended caps, but few methods to enhance contaminant degradation in sediment caps are available. The objective of this study was to determine if, carbon electrodes emplaced within a sediment cap at poised potential could create a redox gradient and provide electron donor for the potential degradation of contaminants. In a simulated sediment cap overlying sediment from the Anacostia River (Washington, DC), electrochemically induced redox gradients were developed within 3 days and maintained over the period of the test (~100 days). Hydrogen and oxygen were produced by water electrolysis at the electrode surfaces and may serve as electron donor and acceptor for contaminant degradation. Electrochemical and geochemical factors that may influence hydrogen production were studied. Hydrogen production displayed zero order kinetics with ~75% coulombic efficiency and rates were proportional to the applied potential between 2.5V to 5V and not greatly affected by pH. Hydrogen production was promoted by increasing ionic strength and in the presence of natural organic matter. Graphite electrode-stimulated degradation of tetrachlorobenzene in a batch reactor was dependent on applied voltage and production of hydrogen to a concentration above the threshold for biological dechlorination. These findings suggest that electrochemical reactive capping can potentially be used to create “reactive” sediments caps capable of promoting chemical or biological transformations of contaminants within the cap. PMID:20879761

Coal liquefaction process

DOEpatents

Karr, Jr., Clarence

1977-04-19

An improved coal liquefaction process is provided which enables conversion of a coal-oil slurry to a synthetic crude refinable to produce larger yields of gasoline and diesel oil. The process is characterized by a two-step operation applied to the slurry prior to catalytic desulfurization and hydrogenation in which the slurry undergoes partial hydrogenation to crack and hydrogenate asphaltenes and the partially hydrogenated slurry is filtered to remove minerals prior to subsequent catalytic hydrogenation.

Lapping slurry

DOEpatents

Simandl, Ronald F.; Upchurch, Victor S.; Leitten, Michael E.

1999-01-01

Improved lapping slurries provide for easier and more thorough cleaning of alumina workpieces, as well as inhibit corrosion of the lapping table and provide for easier cleaning of the lapping equipment. The unthickened lapping slurry comprises abrasive grains such as diamond abrasive dispersed in a carrier comprising water, glycerine, and triethanolamine. The thickened lapping slurry comprises abrasive grains such as diamond abrasive dispersed in a carrier comprising water, glycerine, triethanolamine, a water soluble silicate, and acid.

Using Frozen Barriers for Containment of Contaminants

DTIC Science & Technology

2017-09-21

barriers are constructed of grout slurry and plastic or steel sheet pilings. Circumferential barriers can be used to completely enclose a source of...2.1.1 Slurry walls A soil-bentonite slurry trench cutoff wall (slurry wall) is excavated and backfilled with grout, cement , or soil-bentonite...installation requires a mixing area, and there is a substantial amount of excavation and the need to dispose of spoil. The advantages of cement -based

Toxicity Evaluation of Pig Slurry Using Luminescent Bacteria and Zebrafish

PubMed Central

Chen, Wenyan; Cai, Qiang; Zhao, Yuan; Zheng, Guojuan; Liang, Yuting

2014-01-01

Biogas slurry has become a serious pollution problem and anaerobic digestion is widely applied to pig manure treatment for environmental protection and energy recovery. To evaluate environmental risk of the emission of biogas slurry, luminescent bacteria (Vibrio fischeri), larvae and embryos of zebrafish (Danio rerio) were used to detect the acute and development toxicity of digested and post-treated slurry. Then the ability of treatment process was evaluated. The results showed that digested slurry displayed strong toxicity to both zebrafish and luminescent bacteria, while the EC50 for luminescent bacteria and the LC50 for larvae were only 6.81% (v/v) and 1.95% (v/v) respectively, and embryonic development was inhibited at just 1% (v/v). Slurry still maintained a high level of toxicity although it had been treated by membrane bioreactor (MBR), while the LC50 of larvae was 75.23% (v/v) and there was a little effect on the development of embryos and V. fischeri; the results also revealed that the zebrafish larvae are more sensitive than embryos and luminescent bacteria to pig slurry. Finally, we also found the toxicity removal rate was higher than 90% after the treatment of MBR according to toxicity tests. In conclusion, further treatment should be used in pig slurry disposal or reused of final effluent. PMID:24995598