Below and above boiling point comparison of microwave irradiation and conductive heating for municipal sludge digestion under identical heating/cooling profiles.

PubMed

Hosseini Koupaie, E; Eskicioglu, C

2015-01-01

This research provides a comprehensive comparison between microwave (MW) and conductive heating (CH) sludge pretreatments under identical heating/cooling profiles at below and above boiling point temperatures. Previous comparison studies were constrained to an uncontrolled or a single heating rate due to lack of a CH equipment simulating MW under identical thermal profiles. In this research, a novel custom-built pressure-sealed vessel which could simulate MW pretreatment under identical heating/cooling profiles was used for CH pretreatment. No statistically significant difference was proven between MW and CH pretreatments in terms of sludge solubilization, anaerobic biogas yield and organics biodegradation rate (p-value>0.05), while statistically significant effects of temperature and heating rate were observed (p-value<0.05). These results explain the contradictory results of previous studies in which only the final temperature (not heating/cooling rates) was controlled. Copyright © 2015 Elsevier Ltd. All rights reserved.

Trees' role in nitrogen leaching after organic, mineral fertilization: a greenhouse experiment.

PubMed

López-Díaz, M L; Rolo, V; Moreno, G

2011-01-01

New sustainable agriculture techniques are arising in response to the environmental problems caused by intensive agriculture, such as nitrate leaching and surface water eutrophication. Organic fertilization (e.g., with sewage sludge) and agroforestry could be used to reduce nutrient leaching. We assessed the efficiency of establishing trees and pasture species in environmentally sensitive, irrigated Mediterranean grassland soils in controlling nitrate leaching. Four vegetation systems-bare soil, pasture species, cherry trees [ (L.) L.], and pasture-tree mixed plantings-and five fertilization treatments-control, two doses of mineral fertilizer, and two doses of organic fertilizer (sewage sludge)-were tested in a greenhouse experiment over 2 yr. In the experiment, the wet and warm climate characteristics of Mediterranean irrigated croplands and the plant-to-plant and soil-to-plant interactions that occur in open-field agroforestry plantations were simulated. Following a factorial design with six replicates, 120 pots (30-cm radius and 120 cm deep) were filled with a sandy, alluvial soil common in the cultivated fluvial plains of the region. The greatest pasture production and tree growth were obtained with sewage sludge application. Both pasture production and tree growth decreased significantly in the pasture-tree mixed planting. Nitrate leaching was negligible in this latter treatment, except under the highest dose of sewage sludge application. The rapid mineralization of sludge suggested that this organic fertilizer should be used very cautiously in warm, irrigated Mediterranean soils. Mixed planting of pasture species and trees, such as , could be a useful tool for mitigating nitrate leaching from irrigated Mediterranean pastures on sandy soils. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Water Utility Lime Sludge Reuse – An Environmental Sorbent ...

EPA Pesticide Factsheets

Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up included a simulated flue gas preparation unit, a lab-scale wet scrubber, and a mercury analyzer system. The influent mercury concentration was based on a range from 22 surveyed power plants. The reactivity of the lime sludge sample for acid neutralization was determined using a method similar to method ASTM C1318-95. Similar experiments were conducted using reagent calcium carbonate and calcium sulfate to obtain baseline data for comparing with the lime sludge test results. The project also evaluated the techno-economic feasibility and sustainable benefits of reusing lime softening sludge. If implemented on a large scale, this transformative approach for recycling waste materials from water treatment utilities at power generation utilities for environmental cleanup can save both water and power utilities millions of dollars. Huge amounts of lime sludge waste, generated from hundreds of water treatment utilities across the U.S., is currently disposed in landfills. This project evaluated a sustainable and economically-attractive approach to the use of lime sludge waste as a valuable resource for power generation utilities.

Leaching of heavy metals and alkylphenolic compounds from fresh and dried sewage sludge.

PubMed

Milinovic, Jelena; Vidal, Miquel; Lacorte, Silvia; Rigol, Anna

2014-02-01

Reusing sewage sludge as a soil fertiliser has become a common alternative to disposal. Although this practice has a few benefits, it may contribute to the medium- and long-term contamination of the trophic chain because sewage sludge may contain heavy metals and organic contaminants. As the leaching of contaminants may depend on the sludge pre-treatment, the leaching of heavy metals (Cu, Ni, Pb, Zn and Cr) and alkylphenolic compounds (APCs) (octylphenol (OP), nonylphenol (NP), nonylphenol-mono-ethoxylate (NP1EO)) was investigated in five fresh and 40 °C dried sewage sludge samples from north-eastern Spain. FT-IR analyses and full-scan GC-MS chromatograms showed that sludge drying changed the nature of organic compounds leading to changes in their solubility. Moreover, sludge drying led to a higher relative contribution of dissolved organic carbon than the particulate organic carbon in the leachates. Leaching of Pb, Zn and Cr was below 5 % in both fresh and dried sludge samples, whereas Cu and Ni leached at rates up to 12 and 43 %, respectively, in some of the dried sludge samples. The leaching yields of OP, NP and NP1EO ranged from 1.3 to 35 % for fresh samples, but they decreased from 0.8 to 3.4 % in dried samples. The decrease in the leachability of APCs observed in dried sludge samples might be attributed to the fact that these compounds are associated with particulate organic matter, with significantly lower concentration or even absent in dried sludge than in fresh sludge samples. Therefore, it is recommended to dry the sludge before its disposal.

POTENTIAL EMISSIONS OF HAZARDOUS ORGANIC COMPOUNDS FROM SEWAGE SLUDGE INCINERATION

EPA Science Inventory

Laboratory thermal decomposition studies were undertaken to evaluate potential organic emissions from sewage sludge incinerators. Precisely controlled thermal decomposition experiments were conducted on sludge spiked with mixtures of hazardous organic compounds, on the mixtures o...

Insight into the adsorption mechanisms of trace organic carbon on biological treatment process.

PubMed

Zolfaghari, Mehdi; Drogui, Patrick; Brar, Satinder Kaur; Buelna, Gerardo; Dubé, Rino

2017-09-01

The presence of recalcitrant dissolved organic matter (DOM) could have a significant effect on the adsorption mechanism and capacity of the sludge for many trace organic carbons (TrOCs). In this study, adsorption of three TrOCs on the sludge and HA was investigated. The results revealed that neutral hydrophilic compounds had an insignificant interaction with both sludge and HA. Positively charged compounds, such as fluoranthene, had more affinity toward HA than sludge with solid/liquid partitioning of 57 and 3.2 L/g, respectively. The adsorption intensity (K f ) of di-2-ethyl hexyl phthalate was 0.5 and 1.13 for the HA and the sludge, respectively. By introducing the sludge to the solution of HA and TrOCs that already reached equilibrium, the sludge adsorption capacity in the presence of HA was investigated. The finding showed that at the lower concentration, adsorption of HA on the sludge was considered as the main removal pathway for the adsorbed emerging contaminants, as 70 mg of HA was adsorbed by a gram of sludge. For the higher concentration, desorption of TrOCs from DOM into the sludge comprised 15-30% of total removal efficiency. CBZ: carbamazepine; DEHP: di-2-ethyl hexyl phthalate; DOM: dissolved organic matter; FLAN: fluoranthene; f oc : fraction of organic carbon; HA: humic acid; Log Kow: octanol-water partition coefficient; PAH: polycyclic aromatic hydrocarbon TS: total solid; TrOCs: trace organic carbons VS: volatile solid.

Anaerobic digestion potential of urban organic waste: a case study in Malmö.

PubMed

Davidsson, Asa; Jansen, Jes la Cour; Appelqvist, Björn; Gruvberger, Christopher; Hallmer, Martin

2007-04-01

A study of existing organic waste types in Malmö, Sweden was performed. The purpose was to gather information about organic waste types in the city to be able to estimate the potential for anaerobic treatment in existing digesters at the wastewater treatment plan (WWTP). The urban organic waste types that could have a significant potential for anaerobic digestion amount to about 50 000 tonnes year(-1) (sludge excluded). Some of the waste types were further evaluated by methane potential tests and continuous pilot-scale digestion. Single-substrate digestion and co-digestion of pre-treated, source-sorted organic fraction of municipal solid waste, wastewater sludge, sludge from grease traps and fruit and vegetable waste were carried out. The experiments showed that codigestion of grease sludge and WWTP sludge was a better way of making use of the methane potential in the grease trap sludge than single-substrate digestion. Another way of increasing the methane production in sludge digesters is to add source-sorted organic fraction of municipal solid waste (SSOFMSW). Adding SSOFMSW (20% of the total volatile solids) gave a 10-15% higher yield than could be expected by comparison with separate digestion of sludge respective SSOFMSW. Co-digestion of sludge and organic waste is beneficial not just for increasing gas production but also for stabilizing the digestion process. This was seen when co-digesting fruit and vegetable waste and sludge. When co-digested with sludge, this waste gave a better result than the separate digestion of fruit and vegetable waste. Considering single-substrate digestion, SSOFMSW is the only waste in the study which makes up a sufficient quantity to be suitable as the base substrate in a full-scale digester that is separated from the sludge digestion. The two types of SSOFMSW tested in the pilot-scale digestion were operated successfully at mesophilic temperature. By adding SSOFMSW, grease trap sludge and fruit and vegetables waste to sludge digesters at the wastewater treatment plant, the yearly energy production from methane could be expected to increase from 24 to 43 GWh.

Concentrations and inactivation of Ascaris eggs and pathogen indicator organisms in wastewater stabilization pond sludge.

PubMed

Nelson, K L

2003-01-01

During treatment in wastewater stabilization ponds (WSPs) many pathogens, in particular helminth eggs, are concentrated in the sludge layer. Because periodic removal of the sludge is often required, information is needed on the concentrations and inactivation of pathogens in the sludge layer to evaluate the public health risk they pose upon removal of the sludge. In this paper, previous reports on the sludge concentrations of various pathogen indicator organisms and helminth eggs are reviewed and results from our own recent experiments are reported. The advantages and disadvantages of several methods for studying inactivation in the sludge layer are discussed, as well as implications for the management of WSP sludge. In our recent experiments, which were conducted at three WSPs in central Mexico, sludge cores, dialysis chambers, and batch experiments were used to measure the inactivation rates of fecal coliform bacteria, fecal enterococci, F+ coliphage, somatic coliphage, and Ascaris eggs. The first-order inactivation rate constants were found to be approximately 0.1, 0.1, 0.01, 0.001, and 0.001 d(-1), respectively. The concentrations of all the organisms were found to vary both vertically and horizontally in the sludge layer; therefore, to determine the maximum and average concentration of organisms in the sludge layer of a WSP, complete sludge cores must be collected from representative locations throughout the pond.

Sorption and Release of Organics by Primary, Anaerobic, and Aerobic Activated Sludge Mixed with Raw Municipal Wastewater

PubMed Central

Modin, Oskar; Saheb Alam, Soroush; Persson, Frank; Wilén, Britt-Marie

2015-01-01

New activated sludge processes that utilize sorption as a major mechanism for organics removal are being developed to maximize energy recovery from wastewater organics, or as enhanced primary treatment technologies. To model and optimize sorption-based activated sludge processes, further knowledge about sorption of organics onto sludge is needed. This study compared primary-, anaerobic-, and aerobic activated sludge as sorbents, determined sorption capacity and kinetics, and investigated some characteristics of the organics being sorbed. Batch sorption assays were carried out without aeration at a mixing velocity of 200 rpm. Only aerobic activated sludge showed net sorption of organics. Sorption of dissolved organics occurred by a near-instantaneous sorption event followed by a slower process that obeyed 1st order kinetics. Sorption of particulates also followed 1st order kinetics but there was no instantaneous sorption event; instead there was a release of particles upon mixing. The 5-min sorption capacity of activated sludge was 6.5±10.8 mg total organic carbon (TOC) per g volatile suspend solids (VSS) for particulate organics and 5.0±4.7 mgTOC/gVSS for dissolved organics. The observed instantaneous sorption appeared to be mainly due to organics larger than 20 kDa in size being sorbed, although molecules with a size of about 200 Da with strong UV absorbance at 215–230 nm were also rapidly removed. PMID:25768429

Changes on sewage sludge stability after greenhouse drying

NASA Astrophysics Data System (ADS)

Soriano-Disla, J. M.; Houot, S.; Imhoff, M.; Valentin, N.; Gómez, I.; Navarro-Pedreño, J.

2009-04-01

The progressive implementation of the Urban Waste Water Treatment Directive 91/271/EEC in all the European member states is increasing the quantities of sewage sludge requiring disposal. Sludge application onto cultivated soils as organic fertilizers allows the recycling of nutrients. The application of only dehydrated sludges has generated many problems including unpleasant odours and difficult management (regarding transport and application) related to their high water content. One way to overcome these problems, in a cheap and clean way, is the drying of sludges using the energy of the sun under greenhouse conditions. This drying may affect sludge chemical characteristics including organic matter stability and nitrogen availability, parameters which have to be controlled for the proper management of dry sludge application onto soils. For this reason, the main aim of this work was to study the impact of greenhouse drying of different sewage sludges on their organic matter stability and nitrogen availability, assessed by biochemical fractionation and mineralization assays. Three sewage sludges were sampled before (dehydrated sludges) and after greenhouse drying (dried sludges). The analyses consisted of: humidity, organic matter, mineral and organic N contents, N and C mineralization during 91-day laboratory incubations in controlled conditions, and biochemical fractionation using the Van Soest procedure. Greenhouse drying decreased the water content from 70-80% to 10% and also the odours, both of which will improve the management of the final product from the perspective of application and transport. We also found that drying reduced the organic matter content of the sludges but not the biodegradability of the remaining carbon. Organic N mineralization occurred during greenhouse drying, explaining why mineral N content tended to increase and the potential mineralization of organic nitrogen decreased after greenhouse drying. The biochemical stability did not change so much except for the one of the sludges, which experienced an important reduction. According to the results, and from a point of view of future soil applications, the balance of the drying process could be considered as positive. It is using a free, renewable and clean energy, which reduces the water content and odours of sludge, thereby improving their management. Except for the water content, there was little modification of the behaviour in soil of greenhouse dried sludges compared to the dehydrated sludges, maintaining its large amount of available nitrogen after drying. Acknowledgements: Jose. M. Soriano-Disla gratefully acknowledges the Spanish Ministry of Innovation and Culture for a research fellowship (AP2005-0320).

An ecological vegetation-activated sludge process (V-ASP) for decentralized wastewater treatment: system development, treatment performance, and mathematical modeling.

PubMed

Yuan, Jiajia; Dong, Wenyi; Sun, Feiyun; Li, Pu; Zhao, Ke

2016-05-01

An environment-friendly decentralized wastewater treatment process that is comprised of activated sludge process (ASP) and wetland vegetation, named as vegetation-activated sludge process (V-ASP), was developed for decentralized wastewater treatment. The long-term experimental results evidenced that the vegetation sequencing batch reactor (V-SBR) process had consistently stable higher removal efficiencies of organic substances and nutrients from domestic wastewater compared with traditional sequencing batch reactor (SBR). The vegetation allocated into V-SBR system could not only remove nutrients through its vegetation transpiration ratio but also provide great surface area for microorganism activity enhancement. This high vegetation transpiration ratio enhanced nutrients removal effectiveness from wastewater mainly by flux enhancement, oxygen and substrate transportation acceleration, and vegetation respiration stimulation. A mathematical model based on ASM2d was successfully established by involving the specific function of vegetation to simulate system performance. The simulation results on the influence of operational parameters on V-ASP treatment effectiveness demonstrated that V-SBR had a high resistance to seasonal temperature fluctuations and influent loading shocking.

Evaluating filterability of different types of sludge by statistical analysis: The role of key organic compounds in extracellular polymeric substances.

PubMed

Xiao, Keke; Chen, Yun; Jiang, Xie; Zhou, Yan

2017-03-01

An investigation was conducted for 20 different types of sludge in order to identify the key organic compounds in extracellular polymeric substances (EPS) that are important in assessing variations of sludge filterability. The different types of sludge varied in initial total solids (TS) content, organic composition and pre-treatment methods. For instance, some of the sludges were pre-treated by acid, ultrasonic, thermal, alkaline, or advanced oxidation technique. The Pearson's correlation results showed significant correlations between sludge filterability and zeta potential, pH, dissolved organic carbon, protein and polysaccharide in soluble EPS (SB EPS), loosely bound EPS (LB EPS) and tightly bound EPS (TB EPS). The principal component analysis (PCA) method was used to further explore correlations between variables and similarities among EPS fractions of different types of sludge. Two principal components were extracted: principal component 1 accounted for 59.24% of total EPS variations, while principal component 2 accounted for 25.46% of total EPS variations. Dissolved organic carbon, protein and polysaccharide in LB EPS showed higher eigenvector projection values than the corresponding compounds in SB EPS and TB EPS in principal component 1. Further characterization of fractionized key organic compounds in LB EPS was conducted with size-exclusion chromatography-organic carbon detection-organic nitrogen detection (LC-OCD-OND). A numerical multiple linear regression model was established to describe relationship between organic compounds in LB EPS and sludge filterability. Copyright © 2016 Elsevier Ltd. All rights reserved.

REVIEW OF ALTERNATIVE ENHANCED CHEMICAL CLEANING OPTIONS FOR SRS WASTE TANKS

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

Hay, M.; Koopman, D.

2009-08-01

A literature review was conducted to support the Task Technical and Quality Assurance Plan for Alternative Enhanced Chemical Cleaning (AECC) for sludge heel removal funded as part of the EM-21 Engineering and Technology program. The goal was to identify potential technologies or enhancements to the baseline oxalic acid cleaning process for chemically dissolving or mobilizing Savannah River Site (SRS) sludge heels. The issues with the potentially large volume of oxalate solids generated from the baseline process have driven an effort to find an improved or enhanced chemical cleaning technology for the tank heels. This literature review builds on a previousmore » review conducted in 2003. A team was charged with evaluating the information in these reviews and developing recommendations of alternative technologies to pursue. The new information in this report supports the conclusion of the previous review that oxalic acid remains the chemical cleaning agent of choice for dissolving the metal oxides and hydroxides found in sludge heels in carbon steel tanks. The potential negative impact of large volumes of sodium oxalate on downstream processes indicates that the amount of oxalic acid used for chemical cleaning needs to be minimized as much as possible or the oxalic acid must be destroyed prior to pH adjustment in the receipt tank. The most straightforward way of minimizing the volume of oxalic acid needed for chemical cleaning is through more effective mechanical cleaning. Using a mineral acid to adjust the pH of the sludge prior to adding oxalic acid may also help to minimize the volume of oxalic acid used in chemical cleaning. If minimization of oxalic acid proves insufficient in reducing the volume of oxalate salts, several methods were found that could be used for oxalic acid destruction. For some waste tank heels, another acid or even caustic treatment (or pretreatment) might be more appropriate than the baseline oxalic acid cleaning process. Caustic treatment of high aluminum sludge heels may be appropriate as a means of reducing oxalic acid usage. Reagents other than oxalic acid may also be needed for removing actinide elements from the tank heels. A systems engineering evaluation (SEE) was performed on the various alternative chemical cleaning reagents and organic oxidation technologies discussed in the literature review. The objective of the evaluation was to develop a short list of chemical cleaning reagents and oxalic acid destruction methods that should be the focus of further research and development. The results of the SEE found that eight of the thirteen organic oxidation technologies scored relatively close together. Six of the chemical cleaning reagents were also recommended for further investigation. Based on the results of the SEE and plan set out in the TTQAP the following broad areas are recommended for future study as part of the AECC task: (1) Basic Chemistry of Sludge Dissolution in Oxalic Acid: A better understanding of the variables effecting dissolution of sludge species is needed to efficiently remove sludge heels while minimizing the use of oxalic acid or other chemical reagents. Tests should investigate the effects of pH, acid concentration, phase ratios, temperature, and kinetics of the dissolution reactions of sludge components with oxalic acid, mineral acids, and combinations of oxalic/mineral acids. Real waste sludge samples should be characterized to obtain additional data on the mineral phases present in sludge heels. (2) Simulant Development Program: Current sludge simulants developed by other programs for use in waste processing tests, while compositionally similar to real sludge waste, generally have more hydrated forms of the major metal phases and dissolve more easily in acids. Better simulants containing the mineral phases identified by real waste characterization should be developed to test chemical cleaning methods. (3) Oxalic Acid Oxidation Technologies: The two Mn based oxidation methods that scored highly in the SEE should be studied to evaluate long term potential. One of the AOP's (UV/O{sub 3}/Solids Separator) is currently being implemented by the SRS liquid waste organization for use in tank heel chemical cleaning. (4) Corrosion Issues: A program will be needed to address potential corrosion issues from the use of low molarity mineral acids and mixtures of oxalic/mineral acids in the waste tanks for short durations. The addition of corrosion inhibitors to the acids to reduce corrosion rates should be investigated.« less

Anaerobic storage as a pretreatment for enhanced biodegradability of dewatered sewage sludge.

PubMed

Xu, Huacheng; He, Pinjing; Wang, Guanzhao; Shao, Liming; Lee, Duujong

2011-01-01

Dewatered sewage sludge is often stored still before further processing and final disposal. This study showed that anaerobic storage of dewatered sewage sludge could hydrolyze organic matter from the sludge matrix, and increase soluble organic acid content from 90 to 2400 mg/L and soluble organic carbon content from 220 to 1650 mg/L. Correspondingly, the contents of proteins, celluloses and hemicelluloses were reduced by 2-9%. Applying anaerobic storage markedly enhanced the efficiency of the subsequent bio-drying process on stored sludge. Correspondingly, biogas and odor gas were produced immediately after commencing the sludge storage. Anaerobic storage with odor control can be applied as a pretreatment process for dewatered sewage sludge in wastewater treatment plants. Copyright © 2010 Elsevier Ltd. All rights reserved.

[Detection of anaerobic processes and microorganisms in immobilized activated sludge of a wastewater treatment plant with intense aeration].

PubMed

Litti, Iu V; Nekrasova, V K; Kulikov, N I; Siman'kova, M V; Nozhevnikova, A N

2013-01-01

Attached activated sludge from the Krasnaya Polyana (Sochi) wastewater treatment plant was studied after the reconstruction by increased aeration and water recycle, as well as by the installation of a bristle carrier for activated sludge immobilization. The activated sludge biofilms developing under conditions of intense aeration were shown to contain both aerobic and anaerobic microorganisms. Activity of a strictly anaerobic methanogenic community was revealed, which degraded organic compounds to methane, further oxidized by aerobic methanotrophs. Volatile fatty acids, the intermediates of anaerobic degradation of complex organic compounds, were used by both aerobic and anaerobic microorganisms. Anaerobic oxidation of ammonium with nitrite (anammox) and the presence of obligate anammox bacteria were revealed in attached activated sludge biofilms. Simultaneous aerobic and anaerobic degradation of organic contaminants by attached activated sludge provides for high rates of water treatment, stability of the activated sludge under variable environmental conditions, and decreased excess sludge formation.

Pretreatment of microbial sludges

DOEpatents

Rivard, Christopher J.; Nagle, Nicholas J.

1995-01-01

Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

Pretreatment of microbial sludges

DOEpatents

Rivard, C.J.; Nagle, N.J.

1995-01-10

Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

Study on improvement of sludge dewaterability with H2O2 cell lysis

NASA Astrophysics Data System (ADS)

Zhuo, Qiongfang; Yi, Hao; Zhang, Zhengke; Wang, Ji; Feng, Lishi; Xu, Zhencheng; Guo, Qingwei; Jin, Zhong; Lan, Yongzhe

2017-12-01

Excess sludge is the product of sewage treatment plants. With continuous perfection of municipal sewage treatment facilities in China, sludge output increases as a result of the growth of sewage treatment plants. Excess sludge has complicated compositions, including heavy metals, PPCPs, persistent organic pollutants. It owns high contents of organic matters and water. High-efficiency and low-cost dehydration of sludge is the key of sludge disposal. How to improve sludge dehydration efficiency is the research hotspot in the world. In this study, effects of hydrogen peroxide content and pH on sludge dehydration were discussed by chemical disintegration technique. The optimal hydrogen peroxide content and pH were discussed, aiming to search a high-efficiency sludge conditioner.

[Effect of agricultural application of municipal sewage sludge on plant-soil system: A review].

PubMed

Liu, Meng Jiao; Xia, Shao Pan; Wang, Jun; Ma, Qing Xu; Wang, Zhong Qiang; Wu, Liang Huan

2017-12-01

Currently, reasonable disposal of municipal sewage sludge is one of the important issues in the field of resources and environmental science. Sludge is rich in large amounts of organic matter and available nutrients, promoting soil fertility, soil physical structure and biological properties. However, sludge contains a variety of heavy metals, organic contaminants and other hazardous substance, especially heavy metals, which are the bottlenecks of agricultural application of sludge. To improve the sewage sludge utilization efficiency and decrease the effect on soil, this essay made a summary on domestic and foreign studies on plant-soil interaction ecosystem with sewage sludge to provide a theoretical basis and scientific guidance for advancing sewage sludge utilization efficiency.

Fluid dynamics simulation for design on sludge drying equipment

NASA Astrophysics Data System (ADS)

Li, Shuiping; Liang, Wang; Kai, Zhang

2017-10-01

Sludge drying equipment is a key component in the sludge drying disposal, the structure of drying equipment directly affects the drying disposal of the sludge, so it is necessary to analyse the performance of the drying equipment with different structure. Fluent software can be very convenient to get the distribution of the flow field and temperature field inside the drying equipment which reflects the performance of the structure. In this paper, the outlet position of the sludge and the shape of the sludge inlet are designed. The geometrical model of the drying equipment is established by using pre-processing software Gambit, and the meshing of the model is carried out. The Eulerian model is used to simulate the flow of each phase and the interaction between them, and the realizable turbulence model is used to simulate the turbulence of each phase. Finally, the simulation results of the scheme are compared and the optimal structure scheme is obtained, the operational requirement is proposed. The CFD theory provides a reliable basis for the drying equipment research and reduces the time and costs of the research.

Characteristics of sludge developed under different loading conditions during UASB reactor start-up and granulation.

PubMed

Ghangrekar, M M; Asolekar, S R; Joshi, S G

2005-03-01

Sludge characteristics available inside the reactor are of vital importance to maximize advantages of UASB reactor. The organic loading rate and sludge loading rate applied during start-up are among the important parameters to govern the sludge characteristics. Effects of these loading rates on the characteristics of the sludge developed are evaluated in six laboratory scale UASB reactors. The sludge characteristics considered are VSS/SS ratio of the sludge, sludge volume index, specific gravity, settling velocity and metal contents of the sludge developed under different loading rates. The experimental results indicate that, for developing good characteristics sludge, during primary start-up from flocculent inoculum sludge, organic loading rate and sludge loading rate should be in the range of 2.0-4.5 kg COD/m3 d and 0.1-0.25 kg COD/kg VSS d, respectively (chemical oxygen demand, COD). Proper sludge granulation and higher COD removal efficiency will be achieved by these loading rates.

Relationship between organic matter humification and bioavailability of sludge-borne copper and cadmium during long-term sludge amendment to soil.

PubMed

Liu, Hongtao

2016-10-01

Recycling of sludge as soil amendment poses certain risk of heavy metals contamination. This study investigated the relationship between organic matter in composted sludge and its heavy metals bioavailability over 7years. Periodic monitoring indicated a gradual increase in organic matter degradation, accompanied by changing degrees of polymerization, i.e., ratio of humic acid (HA)/fulvic acid (FA) coupled with incremental exchangeable fraction of copper (Cu) in sludge, with a growing rate of 74.7%, rather than that in soil. However, cadmium (Cd) in composted sludge exhibited an independent manner. Linear-regression analysis revealed that the total proportion of the Cu active fraction (exchangeable plus carbonate bound) was better correlated with the degree of polymerization (DP) and humification ratio (HR) than the degradation ratio of organic matter. Overall, amount of uptaken Cu was more dependent on the humification degree of organic matter, especially the proportion of HA in humus. Copyright © 2016 Elsevier B.V. All rights reserved.

Define of internal recirculation coefficient for biological wastewater treatment in anoxic and aerobic bioreactors

NASA Astrophysics Data System (ADS)

Rossinskyi, Volodymyr

2018-02-01

The biological wastewater treatment technologies in anoxic and aerobic bioreactors with recycle of sludge mixture are used for the effective removal of organic compounds from wastewater. The change rate of sludge mixture recirculation between bioreactors leads to a change and redistribution of concentrations of organic compounds in sludge mixture in bioreactors and change hydrodynamic regimes in bioreactors. Determination of the coefficient of internal recirculation of sludge mixture between bioreactors is important for the choice of technological parameters of biological treatment (wastewater treatment duration in anoxic and aerobic bioreactors, flow capacity of recirculation pumps). Determination of the coefficient of internal recirculation of sludge mixture requires integrated consideration of hydrodynamic parameter (flow rate), kinetic parameter (rate of oxidation of organic compounds) and physical-chemical parameter of wastewater (concentration of organic compounds). The conducted numerical experiment from the proposed mathematical equations allowed to obtain analytical dependences of the coefficient of internal recirculation sludge mixture between bioreactors on the concentration of organic compounds in wastewater, the duration of wastewater treatment in bioreactors.

Widespread Microbial Adaptation to l-Glutamate-N,N-diacetate (L-GLDA) Following Its Market Introduction in a Consumer Cleaning Product.

PubMed

Itrich, Nina R; McDonough, Kathleen M; van Ginkel, Cornelis G; Bisinger, Ed C; LePage, Jim N; Schaefer, Edward C; Menzies, Jennifer Z; Casteel, Kenneth D; Federle, Thomas W

2015-11-17

l-Glutamate-N,N-diacetate (L-GLDA) was recently introduced in the United States (U.S.) market as a phosphate replacement in automatic dishwashing detergents (ADW). Prior to introduction, L-GLDA exhibited poor biodegradation in OECD 301B Ready Biodegradation Tests inoculated with sludge from U.S. wastewater treatment plants (WWTPs). However, OECD 303A Activated Sludge WWTP Simulation studies showed that with a lag period to allow for growth (40-50 days) and a solids retention time (SRT) that allows establishment of L-GLDA degraders (>15 days), significant biodegradation (>80% dissolved organic carbon removal) would occur. Corresponding to the ADW market launch, a study was undertaken to monitor changes in the ready biodegradability of L-GLDA using activated sludge samples from various U.S. WWTPs. Initially all sludge inocula showed limited biodegradation ability, but as market introduction progressed, both the rate and extent of degradation increased significantly. Within 22 months, L-GLDA was ready biodegradable using inocula from 12 WWTPs. In an OECD 303A study repeated 18 months post launch, significant and sustained carbon removal (>94%) was observed after a 29-day acclimation period. This study systematically documented field adaptation of a new consumer product chemical across a large geographic region and confirmed the ability of laboratory simulation studies to predict field adaptation.

Compacted Sewage Sludge as a Barrier for Tailings: The Heavy Metal Speciation and Total Organic Carbon Content in the Compacted Sludge Specimen

PubMed Central

Zhang, Huyuan; Zhang, Qing; Yang, Bo; Wang, Jinfang

2014-01-01

Acid mine drainage (AMD) was the main environmental problem facing the mining industry. For AMD had high heavy metals content and low pH, the compacted sewage sludge might be a barrier for tailings whose oxidation and weathering produced AMD, with its own carbon source, microorganism reduction ability and impermeability. To study the heavy metals environmental risk, under the simulate AMD, the deionized water (DW), and the pH 2.1 sulfuric acid water (SA) seepage conditions, respectively, the changes of the chemical speciation of heavy metals Cd, Cu, Fe, Ni, Zn and total organic carbon (TOC) content in the compacted sewage sludge were assessed in the different periods. The results indicated according to the distribution of heavy metals, the potential mobility was for Cd: 6.08 under AMD, 7.48 under SA, ∞ under DW; for Cu: 0.08 under AMD, 0.17 under SA, 0.59 under DW; for Fe: 0.15 under AMD, 0.22 under SA, 0.22 under DW; for Ni: 2.60 under AMD, 1.69 under SA, 1.67 under DW; and for Zn: 0.15 under AMD, 0.23 under SA and 0.21 under DW at the second checking time. TOC content firstly decreased from 67.62±0% to 66.29±0.35%, then increased to 67.74±0.65% under the AMD seepage while TOC decreased to 63.30±0.53%, then to 61.33±0.37% under the DW seepage, decreased to 63.86±0.41%, then to 63.28±0.49% under SA seepage. That indicated under the AMD seepage, the suitable microorganisms communities in the compacted sewage sludge were activated. And the heavy metals environmental risk of compacted sewage sludge was lower with AMD condition than with other two. So the compacted sewage sludge as a barrier for tailings was feasible as the aspect of environmental risk assessment. PMID:24979755

Influence of cations on the partition behavior of perfluoroheptanoate (PFHpA) and perfluorohexanesulfonate (PFHxS) on wastewater sludge.

PubMed

Wang, Fei; Shih, Kaimin; Ma, Ruowei; Li, Xiao-yan

2015-07-01

The effects of different cations on the sorption behavior of PFHpA and PFHxS on two types of sludge were investigated in this study. The sodium and potassium ions did not significantly affect PFHpA and PFHxS sorption on different sludge. For calcium and magnesium, the sorption amount of PFAS increased with calcium and magnesium concentration increasing from 1 to 30 mM and then decreased with those increasing from 30 to 100 mM. The sorption level of PFHxS or PFHpA greatly increased with increasing Al3+ and Fe3+ cation concentrations due to the strong sorption and coagulation effects by the formation of aluminum hydroxide (or ferric hydroxide) colloids or precipitates. After the organics in sludge has been removed by thermal treatment, the PFAS sorption on sludge was greatly reduced. Such finding indicated that sorption to organic matter is more important for anionic PFASs than adsorption to mineral surfaces. However, due to the higher content of biological organics, a secondary activated sludge has higher affinity toward PFAS species than chemically enhanced primary treatment sludge. It indicated that the organic types in sludge were also crucial to the sorption levels of PFASs by sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

Decomposition of persistent pharmaceuticals in wastewater by ionizing radiation

NASA Astrophysics Data System (ADS)

Kimura, Atsushi; Osawa, Misako; Taguchi, Mitsumasa

2012-09-01

Pharmaceuticals in wastewater were treated by the combined method of activated sludge and ionizing radiation in laboratory scale. Oseltamivir, aspirin, and ibuprofen at 5 μmol dm-3 in wastewater were decomposed by the activated sludge at reaction time for 4 h. Carbamazepine, ketoprofen, mefenamic acid, clofibric acid, and diclofenac were not biodegraded completely, but were eliminated by γ-ray irradiation at 2 kGy. The rate constants of the reactions of these pharmaceuticals with hydroxyl radicals were estimated by the competition reaction method to be 4.0-10×109 mol-1 dm3 s-1. Decompositions of the pharmaceuticals in wastewater by ionizing radiation were simulated by use of the rate constants and the amount of total organic carbon as parameters. Simulation curves of concentrations of these pharmaceuticals as a function of dose described the experimental data, and the required dose for the elimination of them in wastewater by ionizing radiation can be estimated by this simulation.

[Characteristics of odors and VOCs from sludge direct drying process].

PubMed

Chen, Wen-He; Deng, Ming-Jia; Luo, Hui; Zhang, Jing-Ying; Ding, Wen-Jie; Liu, Jun-Xin; Liu, Jun-Xin

2014-08-01

Co-processing sewage sludge by using the high-temperature feature of cement kiln can realize harmless disposal and energy recycling. In this paper, investigation on characteristics of the flue gas from sludge drying process was carried out in Guangzhou Heidelberg Yuexiu Cement Co., LTD. The composition and the main source of odors and volatile organic compounds (VOCs) emitted during the drying process were analyzed, aimed to provide scientific basis for the treatment of sewage sludge. Results showed that there were a large number of malodorous substances and VOCs in the flue gas. Sulfur dioxide and other sulfur-containing compounds were the main components in the malodorous substances, while benzene derivatives were predominant in VOCs. The compositions of odors and VOCs were influenced by the characteristics of the sludge and the heat medium (kiln tail gas). Total organic compounds in the sludge were significantly decreased after drying. Other organic substances such as volatile fatty acid, protein, and polysaccharide were also obviously reduced. The organic matter in sludge was the main source of VOCs in the flue gas. Part of sulfurous substances, such as sulfur dioxide, carbon disulfide, were from sulfur-containing substances in the sludge, and the rest were from the kiln tail gas itself.

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

Effect of biodegradation on the consolidation properties of a dewatered municipal sewage sludge.

PubMed

O'Kelly, Brendan C

2008-01-01

The effect of biodegradation on the consolidation characteristics of an anaerobically digested, dewatered municipal sewage sludge was studied. Maintained-load oedometer consolidation tests that included measurement of the pore fluid pressure response were conducted on moderately degraded sludge material and saturated bulk samples that had been stored under static conditions and allowed to anaerobically biodegrade further (simulating what would happen in an actual sewage sludge monofill or lagoon condition). Strongly degraded sludge material was produced after a storage period of 13 years at ambient temperatures of 5-15 degrees C, with the total volatile solids reducing from initially 70% to 55%. The sludge materials were highly compressible, although impermeable for practical purposes. Primary consolidation generally occurred very slowly, which was attributed to the microstructure of the solid phase, the composition and viscosity of the pore fluid, ongoing biodegradation and the high organic contents. The coefficient of primary consolidation values decreased from initially about 0.35m2/yr to 0.003-0.03m2/yr with increasing effective stress (sigmav'=3-100kPa). Initially, the strongly degraded sludge material was slightly more permeable, although both the moderately and strongly degraded materials became impermeable for practical purposes (k=10(-9)-10(-12)m/s) below about 650% and 450% water contents, respectively. Secondary compression became more dominant with increasing effective stress with a mean secondary compression index (Calphae) value of 0.9 measured for both the moderately and strongly degraded materials.

Identification of the most sensitive parameters in the activated sludge model implemented in BioWin software.

PubMed

Liwarska-Bizukojc, Ewa; Biernacki, Rafal

2010-10-01

In order to simulate biological wastewater treatment processes, data concerning wastewater and sludge composition, process kinetics and stoichiometry are required. Selection of the most sensitive parameters is an important step of model calibration. The aim of this work is to verify the predictability of the activated sludge model, which is implemented in BioWin software, and select its most influential kinetic and stoichiometric parameters with the help of sensitivity analysis approach. Two different measures of sensitivity are applied: the normalised sensitivity coefficient (S(i,j)) and the mean square sensitivity measure (delta(j)(msqr)). It occurs that 17 kinetic and stoichiometric parameters of the BioWin activated sludge (AS) model can be regarded as influential on the basis of S(i,j) calculations. Half of the influential parameters are associated with growth and decay of phosphorus accumulating organisms (PAOs). The identification of the set of the most sensitive parameters should support the users of this model and initiate the elaboration of determination procedures for the parameters, for which it has not been done yet. Copyright 2010 Elsevier Ltd. All rights reserved.

Energy recovery from wastewater treatment plants through sludge anaerobic digestion: effect of low-organic-content sludge.

PubMed

Zhang, Yuyao; Li, Huan

2017-09-18

During anaerobic digestion, low-organic-content sludge sometimes is used as feedstock, resulting in deteriorated digestion performance. The operational experience of conventional anaerobic digestion cannot be applied to this situation. To investigate the feature of low-organic-content sludge digestion and explain its intrinsic mechanism, batch experiments were conducted using designed feedstock having volatile solids (VS) contents that were 30-64% of total solids (TS). The results showed that the accumulative biogas yield declined proportionally from 173.7 to 64.8 ml/g VS added and organic removal rate decreased from 34.8 to 11.8% with decreasing VS/TS in the substrate. The oligotrophic environment resulting from low-organic-content substrates led to decreased microbial activity and a switch from butyric fermentation to propionic fermentation. A first-order model described the biogas production from the batch experiments very well, and the degradation coefficient decreased from 0.159 to 0.069 day -1 , exhibiting a positive relation with organic content in substrate. The results observed here corroborated with data from published literature on anaerobic digestion of low-organic-content sludge and showed that it may not be feasible to recover energy from sludge with an organic content lower than 50% through mono digestion.

Anaerobic Digestion Model No. 1 Simulation of High Solids Anaerobic Digestion with Feasibility Study for El Gabal El Asfar Water Resource Recovery Facility.

PubMed

Aboulfotoh, Ahmed M

2018-03-01

  Performance of continuous mesophilic high solids anaerobic digestion (HSAD) was simulated using Anaerobic Digestion Model No. 1 (ADM1), under different conditions (solids concentrations, sludge retention time (SRT), organic loading rate (OLR), and type of sludge). Implementation of ADM1, using the proposed biochemical parameters, proved to be a useful tool for the prediction and control of HSAD as the model predicted the behavior of the tested sets of data with considerable accuracy, especially for SRT more than 13 days. The model was then used to investigate the possibility of changing the existing conventional anaerobic digestion (CAD) units in Gabal El Asfar water resource recovery facility into HSAD, instead of establishing new CAD units, and results show that the system will be feasible. HSAD will produce the same bioenergy combined with a decrease in capital, operational, and maintenance costs.

Overall effect of carbon production and nutrient release in sludge holding tank on mainstream biological nutrient removal efficiency.

PubMed

Jabari, Pouria; Yuan, Qiuyan; Oleszkiewicz, Jan A

2017-09-11

The potential of hydrolysis/fermentation of activated sludge in sludge holding tank (SHT) to produce additional carbon for the biological nutrient removal (BNR) process was investigated. The study was conducted in anaerobic batch tests using the BNR sludge (from a full-scale Westside process) and the mixture of BNR sludge with conventional non-BNR activated sludge (to have higher biodegradable particulate chemical oxygen demand (bpCOD) in sludge). The BioWin 4.1 was used to simulate the anaerobic batch test of the BNR sludge. Also, the overall effect of FCOD production and nutrient release on BNR efficiency of the Westside process was estimated. The experimental results showed that the phosphorous uptake of sludge increased during hydrolysis/ fermentation condition up to the point when poly-P was completely utilized; afterwards, it decreased significantly. The BioWin simulation could not predict the loss of aerobic phosphorous uptake after poly-P was depleted. The results showed that in the case of activated sludge with relatively higher bpCOD (originating from plants with short sludge retention time or without primary sedimentation), beneficial effect of SHT on BNR performance is feasible. In order to increase the potential of SHT to enhance BNR efficiency, a relatively low retention time and high sludge load is recommended.

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis

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

Li, Meiyan; Xiao, Benyi; Wang, Xu

Highlights: • Volatiles, particularly proteins, play a key role in sludge combustion. • Sludge combustion performance varies with different sludge organic concentrations. • Carbohydrates significantly affect the combustion rate in the second stage. • Combustion performance of digested sludge is more negative compared with others. - Abstract: Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewagemore » sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric–differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175–300 °C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others.« less

Microwave Thermal Hydrolysis Of Sewage Sludge As A Pretreatment Stage For Anaerobic Digestion

NASA Astrophysics Data System (ADS)

Qiao, W.; Wang, W.; Xun, R.

2008-02-01

This article focuses on the effects of microwave thermal hydrolysis on sewage sludge anaerobic digestion. Volatile suspended solid (VSS) and COD solubilization of treated sludge were investigated. It was found that the microwave hydrolysis provided a rapid and efficient process to release organics from sludge. The increase of organic dissolution ratio was not obvious when holding time was over 5 min. The effect of the VSS solubilization was mainly dependent on temperature. The highest value of VSS dissolving ratio, 36.4%, was obtained at 170 °C for 30 min. COD dissolving ratio was about 25% at 170 °C. BMP test of excess sludge and mixture of primary and excess sludge proved the increase of methane production. Total biogas production of microwave treated mixture sludge increased by 12.9% to 20.2% over control after 30 days digestion. For excess sludge, biogas production was 11.1% to 25.9% higher than untreated sludge.

Including the effects of filamentous bulking sludge during the simulation of wastewater treatment plants using a risk assessment model.

PubMed

Flores-Alsina, Xavier; Comas, Joaquim; Rodriguez-Roda, Ignasi; Gernaey, Krist V; Rosen, Christian

2009-10-01

The main objective of this paper is to demonstrate how including the occurrence of filamentous bulking sludge in a secondary clarifier model will affect the predicted process performance during the simulation of WWTPs. The IWA Benchmark Simulation Model No. 2 (BSM2) is hereby used as a simulation case study. Practically, the proposed approach includes a risk assessment model based on a knowledge-based decision tree to detect favourable conditions for the development of filamentous bulking sludge. Once such conditions are detected, the settling characteristics of the secondary clarifier model are automatically changed during the simulation by modifying the settling model parameters to mimic the effect of growth of filamentous bacteria. The simulation results demonstrate that including effects of filamentous bulking in the secondary clarifier model results in a more realistic plant performance. Particularly, during the periods when the conditions for the development of filamentous bulking sludge are favourable--leading to poor activated sludge compaction, low return and waste TSS concentrations and difficulties in maintaining the biomass in the aeration basins--a subsequent reduction in overall pollution removal efficiency is observed. Also, a scenario analysis is conducted to examine i) the influence of sludge retention time (SRT), the external recirculation flow rate (Q(r)) and the air flow rate in the bioreactor (modelled as k(L)a) as factors promoting bulking sludge, and ii) the effect on the model predictions when the settling properties are changed due to a possible proliferation of filamentous microorganisms. Finally, the potentially adverse effects of certain operational procedures are highlighted, since such effects are normally not considered by state-of-the-art models that do not include microbiology-related solids separation problems.

Investigation of the effects of temperature and sludge characteristics on odors and VOC emissions during the drying process of sewage sludge.

PubMed

Ding, Wenjie; Li, Lin; Liu, Junxin

2015-01-01

Sludge drying is a necessary step for sludge disposal. In this study, sludge was collected from two wastewater treatment plants, and dried at different temperatures in the laboratory. The emission of odor and total volatile organic compounds (TVOCs) during the sludge drying process were determined by an online odor monitoring system. The volatile organic compounds (VOCs) in off-gas were analyzed by gas chromatography-mass spectrometry. Results showed that sludge with 30% moisture content could be obtained in 51 minutes under drying temperature 100 °C but only within 27 minutes under 150 °C. Concentration of odor, TVOCs, sulfur-containing compounds (SCCs), and amines were changed with drying temperature and sludge sources. The maximum concentration of odor, TVOCs, SCCs, and amines were 503.13 ppm, 3.01 ppm, 8.15 ppm, and 11.27 ppm, respectively, at drying temperature 100 °C. These values reached 1,250.79, 8.10, 53.51, and 37.80 ppm when sludge dried at 150 °C. Odor concentration had a close relationship with emission of SCCs, amines, and TVOCs. The main VOCs released were benzene series and organic acid. Potential migration of substances in sludge was examined via analysis of off-gas and condensate, aiming to provide scientific data for effective sludge treatment and off-gas control.

Effects of cement on redistribution of trace metals and dissolution of organics in sewage sludge and its inorganic waste-amended products.

PubMed

Lim, T T; Chu, J; Goi, M H

2006-01-01

The suitability of using cement-stabilized sludge products as artificial soils in earth works was evaluated. The sludge products investigated were cemented sludge, cement-treated clay-amended sludge (SS+MC), and cement-treated copper slag-amended sludge (SS+CS). The leachability of lead (Pb), zinc (Zn), copper (Cu), and chromium (Cr) were assessed using the sequential extraction technique, toxicity characteristic leaching procedure (TCLP), NEN 7341 availability test, and column leaching test. The results indicated that Zn leachability was reduced in all the cement-stabilized sludge products. In contrast, Cu was transferred from the organic fraction to the readily leachable phases in the cement-stabilized sludge products and therefore exhibited increased leachability. The increased Cu leachability could be attributed to dissolution of humic substances in the sludge as a result of elevated pH. Good correlation between dissolved organic carbon (DOC) and heavy metal leaching from the cement-stabilized sludge products was observed in the column leaching experiment. Even with a cement percentage as small as 12.5%, calcium silicate hydrate (C-S-H) was formed in the SS+MC and SS+CS products. Inclusion of the marine clay in the SS+MC products could reduce the leaching potentials of Zn, and this was the great advantage of the marine clay over the copper slag for sludge amendment.

Foaming in simulated radioactive waste.

PubMed

Bindal, S K; Nikolov, A D; Wasan, D T; Lambert, D P; Koopman, D C

2001-10-01

Radioactive waste treatment process usually involves concentration of radionuclides before waste can be immobilized by storing it in stable solid form. Foaming is observed at various stages of waste processing like SRAT (sludge receipt and adjustment tank) and melter operations. This kind of foaming greatly limits the process efficiency. The foam encountered can be characterized as a three-phase foam that incorporates finely divided solids (colloidal particles). The solid particles stabilize foaminess in two ways: by adsorption of biphilic particles at the surfaces of foam lamella and by layering of particles trapped inside the foam lamella. During bubble generation and rise, solid particles organize themselves into a layered structure due to confinement inside the foam lamella, and this structure provides a barrier against the coalescence of the bubbles, thereby causing foaming. Our novel capillary force balance apparatus was used to examine the particle-particle interactions, which affect particle layer formation in the foam lamella. Moreover, foaminess shows a maximum with increasing solid particle concentration. To explain the maximum in foaminess, a study was carried out on the simulated sludge, a non-radioactive simulant of the radioactive waste sludge at SRS, to identify the parameters that affect the foaming in a system characterized by the absence of surface-active agents. This three-phase foam does not show any foam stability unlike surfactant-stabilized foam. The parameters investigated were solid particle concentration, heating flux, and electrolyte concentration. The maximum in foaminess was found to be a net result of two countereffects that arise due to particle-particle interactions: structural stabilization and depletion destabilization. It was found that higher electrolyte concentration causes a reduction in foaminess and leads to a smaller bubble size. Higher heating fluxes lead to greater foaminess due to an increased rate of foam lamella generation in the sludge system.

Vermistabilization of sewage sludge (biosolids) by earthworms: converting a potential biohazard destined for landfill disposal into a pathogen-free, nutritive and safe biofertilizer for farms.

PubMed

Sinha, Rajiv K; Herat, Sunil; Bharambe, Gokul; Brahambhatt, Ashish

2010-10-01

Earthworms feed readily upon sludge components, rapidly converting them into vermicompost, reduce the pathogens to safe levels and ingest the heavy metals. Volume is significantly reduced from 1 m³ of wet sludge (80% moisture) to 0.5 m³ of vermicompost (30% moisture). Earthworms have real potential both to increase the rate of aerobic decomposition and composting of organic matter and also to stabilize the organic residues in the sludge--removing the harmful pathogens (by devouring them and also by discharge of antibacterial coelomic fluid) and heavy metals (by bio-accumulation). They also mineralize the essential nutrients nitrogen, phosphorus and potassium from the sludge. It may not be possible to remove toxic substances completely, but at least change the 'chemical make-up' of the sludge to make it harmless to the soil and enable its use as a nutritive organic fertilizer. This method has been found to comply with grade A standards for sludge stabilization.

Impact of the excess sludge modification with selected chemical reagents on the increase of dissolved organic substances concentration compounds transformations in activated sludge.

PubMed

Zawieja, Iwona; Lidia, Wolny; Marta, Próba

2017-07-01

Submission of excess sludge initial disintegration process significantly affects the efficiency of anaerobic stabilization process. Expression of increasing the concentration of organic matter in dissolved form is to increase sludge disintegration. As a result of chemical modification is an increase of the chemical oxygen demand and the concentration of volatile fatty acids. The aim of this study was to determine the impact of the disintegration process with selected chemical reagents to increase the concentration of organic substances in dissolved form. The process of chemical disintegration of excess sludge was treated using the following reagents: Mg(OH) 2 , Ca(OH) 2 , HCl, H 2 SO 4 , H 2 O 2 . The modification was carried out at ambient temperature for 2, 6 and 24h. During sludge disintegration it was noticed the growth of indicators values that confirmed the susceptibility of prepared sludge to biodegradation. Copyright © 2017 Elsevier Inc. All rights reserved.

Carbon mass balance and microbial ecology in a laboratory scale reactor achieving simultaneous sludge reduction and nutrient removal.

PubMed

Huang, Pei; Li, Liang; Kotay, Shireen Meher; Goel, Ramesh

2014-04-15

Solids reduction in activated sludge processes (ASP) at source using process manipulation has been researched widely over the last two-decades. However, the absence of nutrient removal component, lack of understanding on the organic carbon, and limited information on key microbial community in solids minimizing ASP preclude the widespread acceptance of sludge minimizing processes. In this manuscript, we report simultaneous solids reduction through anaerobiosis along with nitrogen and phosphorus removals. The manuscript also reports carbon mass balance using stable isotope of carbon, microbial ecology of nitrifiers and polyphosphate accumulating organisms (PAOs). Two laboratory scale reactors were operated in anaerobic-aerobic-anoxic (A(2)O) mode. One reactor was run in the standard mode (hereafter called the control-SBR) simulating conventional A(2)O type of activated sludge process and the second reactor was run in the sludge minimizing mode (called the modified-SBR). Unlike other research efforts where the sludge minimizing reactor was maintained at nearly infinite solids retention time (SRT). To sustain the efficient nutrient removal, the modified-SBR in this research was operated at a very small solids yield rather than at infinite SRT. Both reactors showed consistent NH3-N, phosphorus and COD removals over a period of 263 days. Both reactors also showed active denitrification during the anoxic phase even if there was no organic carbon source available during this phase, suggesting the presence of denitrifying PAOs (DNPAOs). The observed solids yield in the modified-SBR was 60% less than the observed solids yield in the control-SBR. Specific oxygen uptake rate (SOUR) for the modified-SBR was almost 44% more than the control-SBR under identical feeding conditions, but was nearly the same for both reactors under fasting conditions. The modified-SBR showed greater diversity of ammonia oxidizing bacteria and PAOs compared to the control-SBR. The diversity of PAOs in the modified-SBR was even more interesting in which case novel clades of Candidatus Accumulibacter phosphatis (CAP), an uncultured but widely found PAOs, were found. Copyright © 2014 Elsevier Ltd. All rights reserved.

From agricultural use of sewage sludge to nutrient extraction: A soil science outlook.

PubMed

Kirchmann, Holger; Börjesson, Gunnar; Kätterer, Thomas; Cohen, Yariv

2017-03-01

The composition of municipal wastewater and sewage sludge reflects the use and proliferation of elements and contaminants within society. In Sweden, official statistics show that concentrations of toxic metals in municipal sewage sludge have steadily decreased, by up to 90 %, since the 1970s, due to environmental programmes and statutory limits on metals in sludge and soil. Results from long-term field experiments show that reduced metal pollution during repeated sewage sludge application has reversed negative trends in soil biology. Despite this Swedish success story, organic waste recycling from Swedish towns and cities to arable land is still limited to only about 20 % of the total amount produced. Resistance among industries and consumers to products grown on land treated with sewage sludge may not always be scientifically grounded; however, there are rational obstacles to application of sewage sludge to land based on its inherent properties rather than its content of pollutants. We argue that application of urban organic wastes to soil is an efficient form of recycling for small municipalities, but that organic waste treatment from large cities requires other solutions. The large volumes of sewage sludge collected in towns and cities are not equitably distributed back to arable land because of the following: (i) The high water and low nutrient content in sewage sludge make long-distance transportation too expensive; and (ii) the low plant availability of nutrients in sewage sludge results in small yield increases even after many years of repeated sludge addition. Therefore, nutrient extraction from urban wastes instead of direct organic waste recycling is a possible way forward. The trend for increased combustion of urban wastes will make ash a key waste type in future. Combustion not only concentrates the nutrients in the ash but also leads to metal enrichment; hence, direct application of the ash to land is most often not possible. However, inorganic fertiliser (e.g. mono-ammonium phosphate fertiliser, MAP) can be produced from metal-contaminated sewage sludge ash in a process whereby the metals are removed. We argue that the view on organic waste recycling needs to be diversified in order to improve the urban-rural nutrient cycle, since only recycling urban organic wastes directly is not a viable option to close the urban-rural nutrient cycle. Recovery and recycling of nutrients from organic wastes are a possible solution. When organic waste recycling is complemented by nutrient extraction, some nutrient loops within society can be closed, enabling more sustainable agricultural production in future.

USE OF A VACUUM FILTRATION TECHNIQUE TO STUDY LEACHING OF INDIGENOUS VIRUSES FROM RAW WASTEWATER SLUDGE

EPA Science Inventory

The relative efficiencies of a buffered beef extract solution, sewage secondary effluent, and distilled water, were compared in a study designed to simulate leaching of indigenous enteric viruses from raw primary sewage sludge. The initial sludge liquid fractions, termed sludge l...

Procedures of determining organic trace compounds in municipal sewage sludge-a review.

PubMed

Lindholm-Lehto, Petra C; Ahkola, Heidi S J; Knuutinen, Juha S

2017-02-01

Sewage sludge is the largest by-product generated during the wastewater treatment process. Since large amounts of sludge are being produced, different ways of disposal have been introduced. One tempting option is to use it as fertilizer in agricultural fields due to its high contents of inorganic nutrients. This, however, can be limited by the amount of trace contaminants in the sewage sludge, containing a variety of microbiological pollutants and pathogens but also inorganic and organic contaminants. The bioavailability and the effects of trace contaminants on the microorganisms of soil are still largely unknown as well as their mixture effects. Therefore, there is a need to analyze the sludge to test its suitability before further use. In this article, a variety of sampling, pretreatment, extraction, and analysis methods have been reviewed. Additionally, different organic trace compounds often found in the sewage sludge and their methods of analysis have been compiled. In addition to traditional Soxhlet extraction, the most common extraction methods of organic contaminants in sludge include ultrasonic extraction (USE), supercritical fluid extraction (SFE), microwave-assisted extraction (MAE), and pressurized liquid extraction (PLE) followed by instrumental analysis based on gas or liquid chromatography and mass spectrometry.

Soil microbial biomass and community structure affected by repeated additions of sewage sludge in four Swedish long-term field experiments

NASA Astrophysics Data System (ADS)

Börjesson, G.; Kätterer, T.; Kirchmann, H.

2012-04-01

Soil organic matter is a key attribute of soil fertility. The pool of soil organic C can be increased, either by mineral fertilisers or by adding organic amendments such as sewage sludge. Sewage sludge has positive effects on agricultural soils through the supply of organic matter and essential plant nutrients, but sludge may also contain unwanted heavy metals, xenobiotic substances and pathogens. One obvious effect of long-term sewage sludge addition is a decrease in soil pH, caused by N mineralisation followed by nitrification, sulphate formation and presence of organic acids with the organic matter added. The objective of this study was to investigate the effect of sewage sludge on the microbial biomass and community structure. Materials and methods We analysed soil samples from four sites where sewage sludge has been repeatedly applied in long-term field experiments situated in different parts of Sweden; Ultuna (59°49'N, 17°39'E, started 1956), Lanna (58°21'N, 13°06'E, started 1997-98), Petersborg (55°32'N, 13°00'E, started 1981) and Igelösa (55°45'N, 13°18'E, started 1981). In these four experiments, at least one sewage sludge treatment is included in the experimental design. In the Ultuna experiment, all organic fertilisers, including sewage sludge, are applied every second year, corresponding to 4 ton C ha-1. The Lanna experiment has a similar design, with 8 ton dry matter ha-1 applied every second year. Lanna also has an additional treatment in which metal salts (Cd, Cu, Ni and Zn) are added together with sewage sludge. At Petersborg and Igelösa, two levels of sewage sludge (4 or 12 ton dry matter ha-1 every 4th year) are compared with three levels of NPK fertiliser (0 N, ½ normal N and normal N). Topsoil samples (0-20 cm depth) from the four sites were analysed for total C, total N, pH and PLFAs (phospholipid fatty acids). In addition, crop yields were recorded. Results At all four sites, sewage sludge has had a positive effect on crop yields and soil organic matter levels. Correlations between soil organic matter and total PLFA contents showed highly positive correlations at all sites (with R-values between 0.72 and 0.88). To find out whether sewage sludge through its metal impurities could impose stress on the microbial biomass, we compared the correlations between all different fertilisers used and PLFAs. The slopes of these comparisons revealed that sludge did not differ from other fertiliser treatments, which means that our results contrast earlier reports on negative effects of metals in sludge on soil microbes. The microbial community structure, studied with principal component analysis of individual PLFAs, was strongly affected by changes in soil pH, and at those sites where sewage sludge had caused a low pH, Gram-positive bacteria were more dominant than in the other treatments. However, differences in community structure were larger between sites than between the treatments investigated in this study, thus indicating that the original soil properties were more important for the microbial community structure than the fertiliser treatments.

Organic matter and heavy metals content modeling in sewage sludge treated with reed bed system

NASA Astrophysics Data System (ADS)

Boruszko, Dariusz; Dąbrowski, Wojciech; Malinowski, Paweł

2017-11-01

The long process of sludge stabilization (7-15 years) remarkably reduces the organic matter content and causes the process of sludge humifaction. This paper presents the results of using low-cost methods of sludge treatment in the wastewater treatment plant located in Zambrow, Podlaskie Province. The results of studies on the organic matter and heavy metals content in sewage sludge after treatment in a reed bed system are presented. The aim of the research was to evaluate and model organic matter and heavy metals concentrations during sewage stabilization in reed bed lagoons. The lowest concentration, below 1.3 mg/kg DM of the examined seven heavy metals was mercury (Hg). The highest concentration, exceeding 1300 mg/kg DM was zinc (Zn). The obtained results for the heavy metals in sewage sludge from the reed bed lagoons in Zambrow show that the average content of the analyzed heavy metals is approximately 1620 mg/kg DM. The results of the study demonstrate a high efficiency of low-cost methods used in Zambrów WWTP in terms of the quality of the processed sludge. Sewage sludge from the lowest layer of the reed lagoon (12-14 years of dewatering and transformation) is characterized by the lowest organic matter and heavy metals content. The higher a sediment layer lies, i.e. the shorter the time of processing, the higher is the heavy metals content. This indicates a great role of reeds in the accumulation of these compounds.

CFD Simulation of flow pattern in a bubble column reactor for forming aerobic granules and its development.

PubMed

Fan, Wenwen; Yuan, LinJiang; Li, Yonglin

2018-06-22

The flow pattern is considered to play an important role in the formation of aerobic granular sludge in a bubble column reactor; therefore, it is necessary to understand the behavior of the flow in the reactor. A three-dimensional computational fluid dynamics (CFD) simulation for bubble column reactor was established to visualize the flow patterns of two-phase air-liquid flow and three-phase air-liquid-sludge flow under different ratios of height to diameter (H/D ratio) and superficial gas upflow velocities (SGVs). Moreover, a simulation of the three-phase flow pattern at the same SGV and different characteristics of the sludge was performed in this study. The results show that not only SGV but also properties of sludge involve the transformation of flow behaviors and relative velocity between liquid and sludge. For the original activated sludge floc to cultivate aerobic granules, the flow pattern has nothing to do with sludge, but is influenced by SGV, and the vortices is occurred and the relative velocity is increased with an increase in SGV; the two-phase flow can simplify the three-phase flow that predicts the flow pattern development in bubble column reactor (BCR) for aerobic granulation. For the aerobic granules, the liquid flow behavior developed from the symmetrical circular flow to numbers and small-size vortices with an increase in the sludge diameter, the relative velocity is amount up to u r  = 5.0, it is 29.4 times of original floc sludge.

An ASM/ADM model interface for dynamic plant-wide simulation.

PubMed

Nopens, Ingmar; Batstone, Damien J; Copp, John B; Jeppsson, Ulf; Volcke, Eveline; Alex, Jens; Vanrolleghem, Peter A

2009-04-01

Mathematical modelling has proven to be very useful in process design, operation and optimisation. A recent trend in WWTP modelling is to include the different subunits in so-called plant-wide models rather than focusing on parts of the entire process. One example of a typical plant-wide model is the coupling of an upstream activated sludge plant (including primary settler, and secondary clarifier) to an anaerobic digester for sludge digestion. One of the key challenges when coupling these processes has been the definition of an interface between the well accepted activated sludge model (ASM1) and anaerobic digestion model (ADM1). Current characterisation and interface models have key limitations, the most critical of which is the over-use of X(c) (or lumped complex) variable as a main input to the ADM1. Over-use of X(c) does not allow for variation of degradability, carbon oxidation state or nitrogen content. In addition, achieving a target influent pH through the proper definition of the ionic system can be difficult. In this paper, we define an interface and characterisation model that maps degradable components directly to carbohydrates, proteins and lipids (and their soluble analogues), as well as organic acids, rather than using X(c). While this interface has been designed for use with the Benchmark Simulation Model No. 2 (BSM2), it is widely applicable to ADM1 input characterisation in general. We have demonstrated the model both hypothetically (BSM2), and practically on a full-scale anaerobic digester treating sewage sludge.

Effects of operational conditions on sludge degradation and organic acids formation in low-critical wet air oxidation.

PubMed

Chung, Jinwook; Lee, Mikyung; Ahn, Jaehwan; Bae, Wookeun; Lee, Yong-Woo; Shim, Hojae

2009-02-15

Wet air oxidation processes are to treat highly concentrated organic compounds including refractory materials, sludge, and night soil, and usually operated at supercritical water conditions of high temperature and pressure. In this study, the effects of operational conditions including temperature, pressure, and oxidant dose on sludge degradation and conversion into subsequent intermediates such as organic acids were investigated at low critical wet oxidation conditions. The reaction time and temperature in the wet air oxidation process was shown an important factor affecting the liquefaction of volatile solids, with more significant effect on the thermal hydrolysis reaction rather than the oxidation reaction. The degradation efficiency of sludge and the formation of organic acids were improved with longer reaction time and higher reaction temperature. For the sludge reduction and the organic acids formation under the wet air oxidation, the optimal conditions for reaction temperature, time, pressure, and oxidant dose were shown approximately 240 degrees C, 30min, 60atm, and 2.0L/min, respectively.

Separation of organic ion exchange resins from sludge -- engineering study

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

Duncan, J.B.

1998-08-25

This engineering study evaluates the use of physical separation technologies to separate organic ion exchange resin from KE Basin sludge prior to nitric acid dissolution. This separation is necessitate to prevent nitration of the organics in the acid dissolver. The technologies under consideration are: screening, sedimentation, elutriation. The recommended approach is to first screen the Sludge and resin 300 microns then subject the 300 microns plus material to elutriation.

Nonoxidative removal of organics in the activated sludge process

PubMed Central

Modin, Oskar; Persson, Frank; Wilén, Britt-Marie; Hermansson, Malte

2016-01-01

ABSTRACT The activated sludge process is commonly used to treat wastewater by aerobic oxidation of organic pollutants into carbon dioxide and water. However, several nonoxidative mechanisms can also contribute to removal of organics. Sorption onto activated sludge can remove a large fraction of the colloidal and particulate wastewater organics. Intracellular storage of, e.g., polyhydroxyalkanoates (PHA), triacylglycerides (TAG), or wax esters can convert wastewater organics into precursors for high-value products. Recently, several environmental, economic, and technological drivers have stimulated research on nonoxidative removal of organics for wastewater treatment. In this paper, we review these nonoxidative removal mechanisms as well as the existing and emerging process configurations that make use of them for wastewater treatment. Better utilization of nonoxidative processes in activated sludge could reduce the wasteful aerobic oxidation of organic compounds and lead to more resource-efficient wastewater treatment plants. PMID:27453679

[Drying characteristics and apparent change of sludge granules during drying].

PubMed

Ma, Xue-Wen; Weng, Huan-Xin; Zhang, Jin-Jun

2011-08-01

Three different weight grades of sludge granules (2.5, 5, 10 g) were dried at constant temperature of 100, 200, 300, 400 and 500 degrees C, respectively. Then characteristics of weight loss and change of apparent form during sludge drying were analyzed. Results showed that there were three stages during sludge drying at 100-200 degrees C: acceleration phase, constant-rate phase, and falling-rate phase. At 300-500 degrees C, there were no constant-rate phase, but due to lots of cracks generated at sludge surface, average drying rates were still high. There was a quadratic nonlinear relationship between average drying rate and drying temperature. At 100-200 degrees C, drying processes of different weight grade sludge granules were similar. At 300-500 degrees C, drying processes of same weight grade of sludge granules were similar. Little organic matter decomposed till sludge burning at 100-300 degrees C, while some organic matter began to decompose at the beginning of sludge drying at 400-500 degrees C.

Three-dimensional three-phase model for simulation of hydrodynamics, oxygen mass transfer, carbon oxidation, nitrification and denitrification in an oxidation ditch.

PubMed

Lei, Li; Ni, Jinren

2014-04-15

A three-dimensional three-phase fluid model, supplemented by laboratory data, was developed to simulate the hydrodynamics, oxygen mass transfer, carbon oxidation, nitrification and denitrification processes in an oxidation ditch. The model provided detailed phase information on the liquid flow field, gas hold-up distribution and sludge sedimentation. The three-phase model described water-gas, water-sludge and gas-sludge interactions. Activated sludge was taken to be in a pseudo-solid phase, comprising an initially separated solid phase that was transported and later underwent biological reactions with the surrounding liquidmedia. Floc parameters were modified to improve the sludge viscosity, sludge density, oxygen mass transfer rate, and carbon substrate uptake due to adsorption onto the activated sludge. The validation test results were in very satisfactory agreement with laboratory data on the behavior of activated sludge in an oxidation ditch. By coupling species transport and biological process models, reasonable predictions are made of: (1) the biochemical kinetics of dissolved oxygen, chemical oxygen demand (COD) and nitrogen variation, and (2) the physical kinematics of sludge sedimentation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of sludge age on methanogenic and glycogen accumulating organisms in an aerobic granular sludge process fed with methanol and acetate

PubMed Central

Pronk, M; Abbas, B; Kleerebezem, R; van Loosdrecht, M C M

2015-01-01

The influence of sludge age on granular sludge formation and microbial population dynamics in a methanol- and acetate-fed aerobic granular sludge system operated at 35°C was investigated. During anaerobic feeding of the reactor, methanol was initially converted to methane by methylotrophic methanogens. These methanogens were able to withstand the relatively long aeration periods. Lowering the anaerobic solid retention time (SRT) from 17 to 8 days enabled selective removal of the methanogens and prevented unwanted methane formation. In absence of methanogens, methanol was converted aerobically, while granule formation remained stable. At high SRT values (51 days), γ-Proteobacteria were responsible for acetate removal through anaerobic uptake and subsequent aerobic growth on storage polymers formed [so called metabolism of glycogen-accumulating organisms (GAO)]. When lowering the SRT (24 days), Defluviicoccus-related organisms (cluster II) belonging to the α-Proteobacteria outcompeted acetate consuming γ-Proteobacteria at 35°C. DNA from the Defluviicoccus-related organisms in cluster II was not extracted by the standard DNA extraction method but with liquid nitrogen, which showed to be more effective. Remarkably, the two GAO types of organisms grew separately in two clearly different types of granules. This work further highlights the potential of aerobic granular sludge systems to effectively influence the microbial communities through sludge age control in order to optimize the wastewater treatment processes. PMID:26059251

Simulation of substrate degradation in composting of sewage sludge

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

Zhang Jun; Gao Ding, E-mail: gaod@igsnrr.ac.c; Chen Tongbin

2010-10-15

To simulate the substrate degradation kinetics of the composting process, this paper develops a mathematical model with a first-order reaction assumption and heat/mass balance equations. A pilot-scale composting test with a mixture of sewage sludge and wheat straw was conducted in an insulated reactor. The BVS (biodegradable volatile solids) degradation process, matrix mass, MC (moisture content), DM (dry matter) and VS (volatile solid) were simulated numerically by the model and experimental data. The numerical simulation offered a method for simulating k (the first-order rate constant) and estimating k{sub 20} (the first-order rate constant at 20 {sup o}C). After comparison withmore » experimental values, the relative error of the simulation value of the mass of the compost at maturity was 0.22%, MC 2.9%, DM 4.9% and VS 5.2%, which mean that the simulation is a good fit. The k of sewage sludge was simulated, and k{sub 20}, k{sub 20s} (first-order rate coefficient of slow fraction of BVS at 20 {sup o}C) of the sewage sludge were estimated as 0.082 and 0.015 d{sup -1}, respectively.« less

Acidogenic fermentation of iron-enhanced primary sedimentation sludge under different pH conditions for production of volatile fatty acids.

PubMed

Lin, Lin; Li, Xiao-Yan

2018-03-01

Iron-based chemically enhanced primary sedimentation (CEPS) is increasingly adopted for wastewater treatment in mega cities, producing a large amount of sludge (Fe-sludge) with a high content of organics for potential organic resource recovery. In this experimental study, acidogenic fermentation was applied treat FeCl 3 -based CEPS sludge for production of volatile fatty acids (VFAs) at different pHs. Batch fermentation tests on the Fe-sludge with an organic content of 10 g-COD/L showed that the maximum VFAs production reached 2782.2 mg-COD/L in the reactor without pH control, and it reached 688.4, 3095.3, and 2603.7 mg-COD/L in reactors with pHs kept at 5.0, 6.0 and 8.0, respectively. Analysis of the acidogenesis kinetics and enzymatic activity indicated that the alkaline pH could accelerate the rate of organic hydrolysis but inhibited the further organic conversion to VFAs. In semi-continuous sludge fermentation tests, the VFAs yield in the pH6 reactor was 20% higher than that in the control reactor without pH regulation, while the VFAs yield in the pH8 reactor was 10% lower than the control. Illumina MiSeq sequencing revealed that key functional microorganisms known for effective sludge fermentation, including Bacteroidia and Erysipelotrichi, were enriched in the pH6 reactor with an enhanced VFAs production, while Clostridia became more abundant in the pH8 reactor to stand the unfavorable pH condition. The research presented acidogenic fermentation as an effective process for CEPS sludge treatment and organic resource recovery and provided the first insight into the related microbial community dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Suppression of Native Soil Organic Matter Decomposition by Post-Fermentation Sludge in Agriculture Soil as Assessed by 13C Natural Abundance

NASA Astrophysics Data System (ADS)

Stelmach, W.; Bieganowski, A.; Kuzyakov, Y.

2016-12-01

Anaerobic digestion of organic wastes results in the production of biogas and post-fermentation sludge. Post-fermentation sludge, which is rich in nutrients and contains more easily accessible inorganic-N than comparable composts, can be used as an alternative fertilizer in organic agriculture systems. While the effects of post fermentation sludge application on crop health and productivity have been extensively studied, little is known about its effects on soil parameters and long-term soil health. Thus, the main aim of this study was to determine the effects of post-fermentation sludge fertilization on agriculture soil quality. Specifically, it examined the efficiency and sequence of sludge utilisation by microorganisms and its influence on the utilisation/stabilization of native soil organic matter (SOM).To determine changes in SOM turnover after the addition of sludge, we utilized a natural stable carbon isotope labelling approach. Sludge produced from C4 plant residues (e.g. maize) was applied to soil under C3 cropping, resulting in distinct stable isotope signatures of fertilizer and SOM. Measuring the carbon isotope composition of CO2 produced in this microcosm experiment permitted accurate determination of the proportion of CO2 fluxes arising from both C sources. The addition of post-fermentation sludge increased the CO2 emissions from the soil by 30%. δ13C analysis of the total CO2 efflux revealed that post-fermentation sludge decreased SOM decomposition by 42% compared to control. Only 34% of the post-fermentation sludge had been mineralized after two months of incubation in the soil.The collective results of our study reveal that application of post-fermentation sludge suppresses SOM decomposition, suggesting its use as a fertilizer could positively influence long-term soil quality. Finally, the success of the natural abundance microcosm labeling approach in our study supports its use as an effective method of analyzing the effects of various fertilization techniques on soil nutrient retention.

TRANSPORT OF SEWAGE SLUDGE

EPA Science Inventory

This project was initiated with the overall objective of developing organized information pertaining to the costs of various sewage sludge transport systems. Transport of liquid and dewatered sludge by truck and rail and liquid sludge by barge and pipeline is included. The report...

Preliminary investigation of the microwave pyrolysis mechanism of sludge based on high frequency structure simulator simulation of the electromagnetic field distribution.

PubMed

Ma, Rui; Yuan, Nana; Sun, Shichang; Zhang, Peixin; Fang, Lin; Zhang, Xianghua; Zhao, Xuxin

2017-06-01

Under microwave irradiation, raw sludge was pyrolyzed mainly by evaporation of water, with a weight loss ratio of 84.8% and a maximum temperature not exceeding 200°C. High-temperature pyrolysis of SiC sludge could be realized, with a weight loss ratio of 93.4% and a final pyrolysis temperature of 1131.7°C. Variations between the electric field intensity distribution are the main reason for the differences of pyrolysis efficiencies. HFSS simulation showed that the electric field intensity of the raw sludge gradually decreased from 2.94×10 4 V/m to 0.88×10 4 V/m when pyrolysis ends, while that of SiC sludge decreased from 3.73×10 4 V/m at the beginning to 1.28×10 4 V/m, then increased to 4.03×10 4 V/m. The electromagnetic effect is the main factor (r≥0.91) influencing the temperature increase and weight loss of raw sludge. Both the electromagnetic effect and heat conduction effect influenced temperature rise and weight loss of SiC sludge, but the former's influence was comparatively larger. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fractionation of wastewater characteristics for modelling of Firle Sewage Treatment Works, Harare, Zimbabwe

NASA Astrophysics Data System (ADS)

Muserere, Simon Takawira; Hoko, Zvikomborero; Nhapi, Innocent

Varying conditions are required for different species of microorganisms for the complex biological processes taking place within the activated sludge treatment system. It is against the requirement to manage this complex dynamic system that computer simulators were developed to aid in optimising activated sludge treatment processes. These computer simulators require calibration with quality data input that include wastewater fractionation among others. Thus, this research fractionated raw sewage, at Firle Sewage Treatment Works (STW), for calibration of the BioWin simulation model. Firle STW is a 3-stage activated sludge system. Wastewater characteristics of importance for activated sludge process design can be grouped into carbonaceous, nitrogenous and phosphorus compounds. Division of the substrates and compounds into their constituent fractions is called fractionation and is a valuable tool for process assessment. Fractionation can be carried out using bioassay methods or much simpler physico-chemical methods. The bioassay methods require considerable experience with experimental activated sludge systems and associated measurement techniques while the physico-chemical methods are straight forward. Plant raw wastewater fractionation was carried out through two 14-day campaign periods, the first being from 3 to 16 July 2013 and the second was from 1 to 14 October 2013. According to the Zimbabwean Environmental Management Act, and based on the sensitivity of its catchment, Firle STW effluent discharge regulatory standards in mg/L are COD (<60), TN (<10), ammonia (<0.2), and TP (<1). On the other hand Firle STW Unit 4 effluent quality results based on City of Harare records in mg/L during the period of study were COD (90 ± 35), TN (9.0 ± 3.0), ammonia (0.2 ± 0.4) and TP (3.0 ± 1.0). The raw sewage parameter concentrations measured during the study in mg/L and fractions for raw sewage respectively were as follows total COD (680 ± 37), slowly biodegradable COD (456 ± 23), (0.7), readily biodegradable COD (131 ± 11), (0.2), soluble unbiodegradable COD (40 ± 3), (0.06), particulate unbiodegradable COD (53 ± 3) (0.08), total TKN (40 ± 4) mg/L, ammonia (28 ± 6), (0.68), organically bound nitrogen (12 ± 2), (0.32), TP (15 ± 1.4), orthophosphates (9.6 ± 1.4), (0.64), and organically bound TP (5.4 ± 1.4), (0.36), soluble unbiodegradable TP (0.4 ± 0), (0.03), particulate unbiodegradable TP (0.05 ± 0), (0.003). Thus, wastewater at Firle STW was found to be highly biodegradable suggesting optimisation of biological nutrient removal process will generally achieve effluent regulatory standards compliance. Thus, opportunities for plant optimisation do exist of which modelling with the use of a simulator is recommended to achieve recommended effluent standards in addition to reduction of operating costs.

Adsorption of mercury by activated carbon prepared from dried sewage sludge in simulated flue gas.

PubMed

Park, Jeongmin; Lee, Sang-Sup

2018-04-25

Conversion of sewage sludge to activated carbon is attractive as an alternative method to ocean dumping for the disposal of sewage sludge. Injection of activated carbon upstream of particulate matter control devices has been suggested as a method to remove elemental mercury from flue gas. Activated carbon was prepared using various activation temperatures and times and was tested for their mercury adsorption efficiency using lab-scale systems. To understand the effect of the physical property of the activated carbon, its mercury adsorption efficiency was investigated as a function of their Brunauer-Emmett-Teller (BET) surface area. Two simulated flue gas conditions: (1) without hydrogen chloride (HCl) and (2) with 20 ppm HCl, were used to investigate the effect of flue gas composition on the mercury adsorption capacity of activated carbon. Despite very low BET surface area of the prepared sewage sludge activated carbons, their mercury adsorption efficiencies were comparable under both simulated flue gas conditions to those of pinewood and coal activated carbons. After injecting HCl into the simulated flue gas, all sewage sludge activated carbons demonstrated high adsorption efficiencies, i.e., more than 87%, regardless of their BET surface area. IMPLICATIONS We tested activated carbons prepared from dried sewage sludge to investigate the effect of their physical properties on their mercury adsorption efficiency. Using two simulated flue gas conditions, we conducted mercury speciation for the outlet gas. We found that the sewage sludge activated carbon had comparable mercury adsorption efficiency to pinewood and coal activated carbons, and the presence of HCl minimized the effect of physical property of the activated carbon on its mercury adsorption efficiency.

Influences of Different Conditioners on Dehydration Ratio of Activated Sludge

NASA Astrophysics Data System (ADS)

Zhuo, Qiongfang; Zheng, Wenli; Yi, Hao; Chen, Sili; Xu, Zhencheng; Jin, Zhong; Lan, Yongzhe; Guo, Qingwei

2017-11-01

Excess sludge contains a large quantity of water with water content reaching about 97%-99%. Besides microorganisms and germs, the sludge is of complicated composition, including heavy metals, persistent organic pollutants, PPCPs, endocrine disrupters, etc. It covers a large area with harmfulness, so it needs further treatment. However, due to existence of extracellular polymeric substances in the sludge, the sludge has poor dehydration property, so how to improve dehydration of sludge is a difficult point in water treatment industry. Chemical conditioning—mechanical dehydration method is sludge dehydration technology which has been widely applied in China. Most sludge treatment plants use organic and inorganic conditioners like polyacrylamide (PAM), polyaluminum chloride (PAC) and polymerized ferrous sulfate (PFS), etc. With characteristics of low toxicity and degradation resistance, these conditioners pose potential risks to the environment and they are adverse to follow-up resource utilization. Therefore, influences of 17 conditioners on sludge dehydration ratio were discussed in this paper, expecting to seek for green, environmentally friendly and highly efficient conditioner so as to improve resource utilization ratio of sludge.

Application of a battery of biotests for the determination of leachate toxicity to bacteria and invertebrates from sewage sludge-amended soil.

PubMed

Malara, Anna; Oleszczuk, Patryk

2013-05-01

The objective of the study was to determine the leachates toxicity from sewage sludge-amended soils (sandy and loamy). Samples originated from a plot experiment realized over a period of 29 months. Two types of soil were fertilized with sewage sludges at the dose of 3 % (90 t/ha). Soil samples were taken after 0, 7, 17, and 29 months from the application of sewage sludges. Leachates were obtained according to the EN 12457-2 protocol. The following commercial tests were applied for the estimation of the toxicity: Microtox (Vibrio fischeri), Microbial assay for toxic risk assessment (ten bacteria and one yeast), Protoxkit F (Tetrahymena thermophila), Rotoxkit F (Brachionus calyciflorus), and Daphtoxkit F (Daphnia magna). The test organisms displayed varied toxicity with relation to the soils amended with sewage sludges. The toxicity of the leachates depended both on the soil type and on the kind of sewage sludge applied. Notable differences were also observed in the sensitivity of the test organisms to the presence of sewage sludge in the soil. The highest sensitivity was a characteristic of B. calyciflorus, while the lowest sensitivity to the presence of the sludges was revealed by the protozoa T. thermophila. Throughout the periods of the study, constant variations of toxicity were observed for most of the test organisms. The intensity as well as the range of those variations depended both on the kind of test organism and on the kind of sludge and soil type. In most cases, an increase of the toxicity of soils amended with the sewage sludges was observed after 29 months of the experiment.

Evaluation of Autothermal Thermophilic Aerobic Digester Performance for the Stabilization of Municipal Wastewater Sludge.

PubMed

Shokoohi, Reza; Rahmani, Alireza; Asgari, Ghorban; Dargahi, Abdollah; Vaziri, Yaser; Abbasi, Mohammad Attar

2017-01-01

Sludge stabilization process in terms of operational, environmental and economic indexes is the most important stage of treatment and its disposal. This study was aimed to determine the performance of Autothermal Thermophilic Aerobic Digestion (ATAD) system as one of the low-cost and biocompatible methods of sludge treatment. This study has been done using a laboratory scale Autothermal Thermophilic Aerobic Digestion (ATAD). The reactor was consisted of two polyethylene tanks with a final capacity of 100 L for each tank. Both tanks with all fittings were installed on a metal frame. The variables of study were temperature, dissolved oxygen, pH, volatile organic compounds, total solids, COD and the number of Ascaris eggs and fecal coliforms per gram of dry matter of the sludge. The temperature was measured hourly and the pH and dissolved oxygen were measured and controlled twice per day. One-way ANNOVA was applied to analyze reasults. According to the results, the temperature of sludge increased from 11.7-61.2°C by biological reactions. Pathogen organisms were reduced from 80×106 to 503 in number during 72 h. After 6 days pathogen organisms and Ascaris eggs were removed completely. Volatile organic compounds and COD were reduced 42 and 38.3% respectively during the 6 days. It is concluded that the performance of ATAD in removing organic compounds from wastewater sludge were desirable. Resulted sludge from stabilization process were appropriate for use in agriculture as a soil supplement and met the indexes of class A sludge according to EPA's standards (CFR 40 Part 503).

Optimized biogas-fermentation by neural network control.

PubMed

Holubar, P; Zani, L; Hager, M; Fröschl, W; Radak, Z; Braun, R

2003-01-01

In this work several feed-forward back-propagation neural networks (FFBP) were trained in order to model, and subsequently control, methane production in anaerobic digesters. To produce data for the training of the neural nets, four anaerobic continuous stirred tank reactors (CSTR) were operated in steady-state conditions at organic loading rates (Br) of about 2 kg x m(-3) x d(-1) chemical oxygen demand (COD), and disturbed by pulse-like increase of the organic loading rate. For the pulses additional carbon sources were added to the basic feed (surplus- and primary sludge) to simulate cofermentation and to increase the COD. Measured parameters were: gas composition, methane production rate, volatile fatty acid concentration, pH, redox potential, volatile suspended solids and COD of feed and effluent. A hierarchical system of neural nets was developed and embedded in a Decision Support System (DSS). A 3-3-1 FFBP simulated the pH with a regression coefficient of 0.82. A 9-3-3 FFBP simulated the volatile fatty acid concentration in the sludge with a regression coefficient of 0.86. And a 9-3-2 FFBP simulated the gas production and gas composition with a regression coefficient of 0.90 and 0.80 respectively. A lab-scale anaerobic CSTR controlled by this tool was able to maintain a methane concentration of about 60% at a rather high gas production rate of between 5 to 5.6 m3 x m(-3) x d(-1).

Determining organic pollutants in automotive industry sludge.

PubMed

Munaretto, Juliana S; Wonghon, Audrey L; von Mühlen, Carin

2012-12-01

In Brazil, the policy for disposing industrial sludge is changing from an emphasis on using controlled landfills to other treatment or co-processing methods; however, the monitoring of organic pollutants is not mandatory. The present study evaluated two general screening methods for organic pollutants in sludge generated in an automotive industrial complex in southern Brazil. The screening was performed using Soxhlet and sonication extractions and Gas Chromatograph coupled with Quadrupole Mass Spectrometry (GC/qMS). It was concluded that both techniques were effective and that most of the compounds identified were alkanes, phenols and esters. Important pollutants were detected in the sludge, which confirms the necessity of monitoring this type of residue.

The San Francisco Bay - Delta Wastewater and Residual Solids Management Study. Volume III. Technical Appendix. Wastewater Residual Solids Management Study

DTIC Science & Technology

1972-08-01

of public health hazards and may alter reuse approaches to de -emphasize the fertilizer uses of these sludges because of the heavy metals involved...materials are removed with organic sludges, or lime sludges where that process is used. Toxic solids would typically include phenols and heavy metals , 80...solids would typically include phenols and heavy metals , 80 percent and 40 percent respectively being removable with the organic sludges. - 8

The influence of organic amendment and nickel pollution on tomato fruit yield and quality.

PubMed

Palacios, G; Carbonell-Barrachina, A; Gómez, I; Mataix, J

1999-01-01

The effects of organic fertilization (sludge application) and/or different levels of Ni pollution on tomato fruit yield, quality, nutrition, and Ni accumulation were investigated. The mass loading of sewage sludge solids used in this study for the amendment of a calcareous soil with low organic matter content was 2% (w/w). A control with no sewage sludge amendment was also included (S). Nickel was added to the sludge amended soil at 0, 60, 120 and 240 mg kg-1 concentrations. Sewage sludge addition to the calcareous soil significantly increased fruit yield but did not adversely affect the quality and nutritional status of the tomato fruit. The results demonstrated that sewage sludge could be successfully used as a horticultural fertilizer. Only the highest addition rate of Ni (240 mg kg-1) to an organic amended calcareous soil had negative effects on fruit yield and quality, and caused a Ni accumulation in fruit that could be considered as a hazard for human health. Thus, no toxic problems will be encountered in tomato fruit due to Ni pollution provided the total Ni (soil Ni plus Ni incorporated with sludge amendment) concentration is kept below the maximum concentration of Ni allowed for agricultural alkaline soils in Spain (112 mg Ni kg-1).

Intensification of anaerobic digestion efficiency with use of mechanical excess sludge disintegration in the context of increased energy production in wastewater treatment plants

NASA Astrophysics Data System (ADS)

Żubrowska-Sudoł, Monika; Podedworna, Jolanta; Bisak, Agnieszka; Sytek-Szmeichel, Katarzyna; Krawczyk, Piotr; Garlicka, Agnieszka

2017-11-01

The main goal of the study was to evaluate the effects of mechanical sludge disintegration for enhancing full scale anaerobic digestion of municipal sludge. Batch disintegration tests and lab dewatering tests were also performed aiming at determining the release of organic compounds and assessing the impact of disintegration of excess sludge before the fermentation process of mixed sludge on the dewaterability of post-fermented sludge, respectively. In the study a disc disintegrator driven by a motor with a power of 30 kW, revolutions n = 2950 rpm has been used. It was shown that with increase of energy consumed in the disintegration, the increased amounts of organic compounds were released from the sludge. It was also documented that the introduction of the excess sludge disintegration prior to fermentation tank, resulted in a significant increase in biogas production (by an average of 33.9%) and in increase in volatile total solids reduction in the fermented sludge (by an average of 22.7%). Moreover, the obtained results indicate the possibility of obtaining a higher degree of sludge dewatering, which was subjected to anaerobic stabilization with using disintegrated excess sludge.

Risk assessments of polybrominated diphenyl ethers (PBDEs) during sludge application in China

NASA Astrophysics Data System (ADS)

Qian, Jun

2018-02-01

Due to increasingly less space in municipal environment, waste management has become an urgent issue worldwide. As one of common municipal waste, sewage sludge from wastewater treatment plants (WWTPs) contains abundant nutrients, some of which can be quite essential for plant growth. In consideration of nutrient recycling and energy saving, sludge application has been frequently promoted in many countries across the world. However, even after several sludge stabilization procedures, sewage sludge may still contain a large variety of toxic pollutants, especially some emerging organic contaminants (EOCs). Applied in various household products and plastic industries as additives, polybrominated diphenyl ethers (PBDEs) have been constantly detected in sewage sludge samples from several cities in China since 2005, as well as some biosolid samples after sludge stabilization processes, suggesting their strong persistence and wide occurrence. During sludge application onto farmland soils, PBDEs may desorb from sludge particles and get attached by soil organic matter (SOM), followed by plant root uptake and translocation to aboveground tissues. In this study, data about current pollution of PBDEs in sewage sludge samples from China was reviewed, and the potential risks during sludge application was comprehensively assessed.

Achilles heel of environmental risk from recycling of sludge to soil as amendment: A summary in recent ten years (2007-2016).

PubMed

Liu, Hong-Tao

2016-10-01

Recycling sludge as a soil amendment has both positive and negative effects because of its enrichment in both nutrients and contaminants. So far, the negative effect has to be extensively investigated that the severities of different types of contaminants also remain unclear. The environmental behavior and risk of organic contaminant and pharmaceuticals, heavy metal and salt as well as pathogenic microorganisms brought by sludge amendment are summarized and discussed here. Organic contaminants and pharmaceuticals are typically found at low concentrations in sludge, the risks from sludge-amended soil decrease over time owing to its biodegradability. On the other hand, application of sludge generally increases soil salinity, which may cause physiological damage to plants grown in sludge-amended soil. In some extent, this negative effect can be alleviated by means of dilution; however, greater attention should be paid to long term increasing possible risk of eutrophication. Heavy metal (particularly of mobile heavy metals, such as Cd) with high concentrations in sludge and soil receiving considerable sludge can cause its incremental abundance in soil and crop contamination, further posing risks to humans, but most cases showed that there remained not excessive in heavy metal caused by sludge amendment. It is worth noting that increasing soil organic matter content may reduce transfer of heavy metal from soil to crops, but not restrict its uptake by crops at all. Combined literature together, it is summarized that heavy metal becomes a relatively severe bottleneck in recycling of sludge as soil amendment due to its non-biodegradability and potential damage to health by adventuring contamination from agricultural products. Particular attention should therefore be paid to long term monitoring the change of heavy metals concentration in sludge amended soil. 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

Microbial adaptation to biodegrade toxic organic micro-pollutants in membrane bioreactor using different sludge sources.

PubMed

Boonnorat, Jarungwit; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

2014-08-01

Biodegradation of toxic organic micro-pollutants in municipal solid waste (MSW) leachate by membrane bioreactor (MBR) was investigated. The MBR systems were seeded with different sludge sources, one was from a pilot-scale MBR system treating MSW leachate and the other was from an activated sludge sewage treatment plant. The biodegradation of BPA, 2,6-DTBP, BHT, DEP, DBP and DEHP, DCP and BBzP, by sludge from both reactors were found improved with time. However, enhanced biodegradation of micro-pollutants was observed in MBR operated under long sludge age condition. Bacterial population analyses determined by PCR-DGGE revealed the development of phenol and phthalate degrading bacteria consortium in MBR sludge during its operation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Response of wine grape growth, development and the transfer of copper, lead, and cadmium in soil-fruit system to sludge compost amendment.

PubMed

Liu, Hong-Tao; Wang, Yan-Wen; Huang, Wei-Dong; Lei, Mei

2016-12-01

Sludge is an organic waste after domestic sewage being treated and contains phytonutrients and organic matter. In this study, recycling of sludge compost (SC) and its compound fertilizer (SCF) to wine grape resulted in improvement in vegetative growth, reproductive development of wine grape, and potential wine quality of grape fruit. The amounts of Cu, Pb, and Cd in grape fruit were significantly higher in response to sludge amendment than in the control, but were all below the permissible limits for agricultural product. The contents of Cu and Pb in sludge-amended soil decreased with increasing soil depth, but Cd content increased with soil depth. Ongoing monitoring of on mobility of Cd downward is proposed with sludge recycling to wine grape soil.

Changes in physical properties of sandy soil after long-term compost treatment

NASA Astrophysics Data System (ADS)

Aranyos, József Tibor; Tomócsik, Attila; Makádi, Marianna; Mészáros, József; Blaskó, Lajos

2016-07-01

Studying the long-term effect of composted sewage sludge application on chemical, physical and biological properties of soil, an experiment was established in 2003 at the Research Institute of Nyíregyháza in Hungary. The applied compost was prepared from sewage sludge (40%), straw (25%), bentonite (5%) and rhyolite (30%). The compost was ploughed into the 0-25 cm soil layer every 3rd year in the following amounts: 0, 9, 18 and 27 Mg ha-1 of dry matter. As expected, the compost application improved the structure of sandy soil, which is related with an increase in the organic matter content of soil. The infiltration into soil was improved significantly, reducing the water erosion under simulated high intensity rainfall. The soil compaction level was reduced in the first year after compost re-treatment. In accordance with the decrease in bulk density, the air permeability of soil increased tendentially. However, in the second year the positive effects of compost application were observed only in the plots treated with the highest compost dose because of quick degradation of the organic matter. According to the results, the sewage sludge compost seems to be an effective soil improving material for acidic sandy soils, but the beneficial effect of application lasts only for two years.

Effect of SBR feeding strategy and feed composition on the stability of aerobic granular sludge in the treatment of a simulated textile wastewater.

PubMed

Franca, R D G; Ortigueira, J; Pinheiro, H M; Lourenço, N D

2017-09-01

Treatment of the highly polluting and variable textile industry wastewater using aerobic granular sludge (AGS) sequencing batch reactors (SBRs) has been recently suggested. Aiming to develop this technology application, two feeding strategies were compared regarding the capacity of anaerobic-aerobic SBRs to deal with disturbances in the composition of the simulated textile wastewater feed. Both a statically fed, anaerobic-aerobic SBR and an anaerobic plug-flow fed, anaerobic-aerobic SBR could cope with shocks of high azo dye concentration and organic load, the overall chemical oxygen demand and color removal yields being rapidly restored to 80%. Yet, subsequent azo dye metabolite bioconversion was not observed, along the 315-day run. Moreover, switching from a starch-based substrate to acetate in the feed composition deteriorated AGS stability. Overall, the plug-flow fed SBR recovered more rapidly from the imposed disturbances. Further research is needed towards guaranteeing long-term AGS stability during the treatment of textile wastewater.

Land application technique for the treatment and disposal of sewage sludge.

PubMed

Zain, S M; Basri, H; Suja, F; Jaafar, O

2002-01-01

Some of the major concerns when applying sewage sludge to land include the potential effect on pH and cation exchange capacity; the mobility and the accumulation of heavy metals in sludge treated soil; the potential of applying too much nutrients and the problems associated with odors and insects. The main objective of this study is to identify the effects of sewage sludge application on the physical and chemical properties of sludge treated soil. Sewage sludge was applied to soil at various rates ranging from 0 L/m2 to 341 L/m2. In order to simulate the natural environment, the study was carried out at a pilot treatment site (5.2 m x 6.7 m) in an open area, covered with transparent roofing material to allow natural sunlight to pass through. Simulated rain was applied by means of a sprinkler system. Data obtained from sludge treated soil showed that the pH values decreased when the application rates were increased and the application period prolonged. The effect of sewage sludge on cation exchange capacity was not so clear; the values obtained for every application rate of sewage sludge did not indicate any consistent behaviour. The mobility of heavy metals in soils treated with sludge were described by observing the changes in the concentration of the heavy metals. The study showed that Cd has the highest mobility in sludge treated soil followed by Cu, Cr, Zn, Ni and Pb.

Sewage sludge, compost and other representative organic wastes as agricultural soil amendments: Benefits versus limiting factors.

PubMed

Alvarenga, Paula; Mourinha, Clarisse; Farto, Márcia; Santos, Teresa; Palma, Patrícia; Sengo, Joana; Morais, Marie-Christine; Cunha-Queda, Cristina

2015-06-01

Nine different samples of sewage sludges, composts and other representative organic wastes, with potential interest to be used as agricultural soil amendments, were characterized: municipal sewage sludge (SS1 and SS2), agro industrial sludge (AIS), municipal slaughterhouse sludge (MSS), mixed municipal solid waste compost (MMSWC), agricultural wastes compost (AWC), compost produced from agricultural wastes and sewage sludge (AWSSC), pig slurry digestate (PSD) and paper mill wastes (PMW). The characterization was made considering their: (i) physicochemical parameters, (ii) total and bioavailable heavy metals (Cd, Cr, Cu, Ni, Pb, Zn and Hg), (iii) organic contaminants, (iv) pathogenic microorganisms and (v) stability and phytotoxicity indicators. All the sludges, municipal or other, comply with the requirements of the legislation regarding the possibility of their application to agricultural soil (with the exception of SS2, due to its pathogenic microorganisms content), with a content of organic matter and nutrients that make them interesting to be applied to soil. The composts presented, in general, some constraints regarding their application to soil, and their impairment was due to the existence of heavy metal concentrations exceeding the proposed limit of the draft European legislation. As a consequence, with the exception of AWSSC, most compost samples were not able to meet these quality criteria, which are more conservative for compost than for sewage sludge. From the results, the composting of sewage sludge is recommended as a way to turn a less stabilized waste into a material that is no longer classified as a waste and, judging by the results of this work, with lower heavy metal content than the other composted materials, and without sanitation problems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling integrated fixed-film activated sludge and moving-bed biofilm reactor systems II: evaluation.

PubMed

Boltz, Joshua P; Johnson, Bruce R; Daigger, Glen T; Sandino, Julian; Elenter, Deborah

2009-06-01

A steady-state model presented by Boltz, Johnson, Daigger, and Sandino (2009) describing integrated fixed-film activated sludge (IFAS) and moving-bed biofilm reactor (MBBR) systems has been demonstrated to simulate, with reasonable accuracy, four wastewater treatment configurations with published operational data. Conditions simulated include combined carbon oxidation and nitrification (both IFAS and MBBR), tertiary nitrification MBBR, and post denitrification IFAS with methanol addition as the external carbon source. Simulation results illustrate that the IFAS/MBBR model is sufficiently accurate for describing ammonia-nitrogen reduction, nitrate/nitrite-nitrogen reduction and production, biofilm and suspended biomass distribution, and sludge production.

Pretreatment of high solid microbial sludges

DOEpatents

Rivard, Christopher J.; Nagle, Nicholas J.

1998-01-01

A process and apparatus for pretreating microbial sludges in order to enhance secondary anaerobic digestion. The pretreatment process involves disrupting the cellular integrity of municipal sewage sludge through a combination of thermal, explosive decompression and shear forces. The sludge is pressurized and pumped to a pretreatment reactor where it is mixed with steam to heat and soften the sludge. The pressure of the sludge is suddenly reduced and explosive decompression forces are imparted which partially disrupt the cellular integrity of the sludge. Shear forces are then applied to the sludge to further disrupt the cellular integrity of the sludge. Disrupting cellular integrity releases both soluble and insoluble organic constituents and thereby renders municipal sewage sludge more amenable to secondary anaerobic digestion.

Important operational parameters of membrane bioreactor-sludge disintegration (MBR-SD) system for zero excess sludge production.

PubMed

Yoon, Seong-Hoon

2003-04-01

In order to prevent excess sludge production during wastewater treatment, a membrane bioreactor-sludge disintegration (MBR-SD) system has been introduced, where the disintegrated sludge is recycled to the bioreactor as a feed solution. In this study, a mathematical model was developed by incorporating a sludge disintegration term into the conventional activated sludge model and the relationships among the operational parameters were investigated. A new definition of F/M ratio for the MBR-SD system was suggested to evaluate the actual organic loading rate. The actual F/M ratio was expected to be much higher than the apparent F/M ratio in MBR-SD. The kinetic parameters concerning the biodegradability of organics hardly affect the system performance. Instead, sludge solubilization ratio (alpha) in the SD process and particulate hydrolysis rate constant (k(h)) in biological reaction determine the sludge disintegration number (SDN), which is related with the overall economics of the MBR-SD system. Under reasonable alpha and k(h) values, SDN would range between 3 and 5 which means the amount of sludge required to be disintegrated would be 3-5 times higher for preventing a particular amount of sludge production. Finally, normalized sludge disintegration rate (q/V) which is needed to maintain a certain level of MLSS in the MBR-SD system was calculated as a function of F/V ratio.

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

Disintegration of excess activated sludge--evaluation and experience of full-scale applications.

PubMed

Zábranská, J; Dohányos, M; Jenícek, P; Kutil, J

2006-01-01

Anaerobic digestion of sewage sludge can be improved by introducing a disintegration of excess activated sludge as a pretreatment process. The disintegration brings a deeper degradation of organic matter and less amount of output sludge for disposal, a higher production of biogas and consequently energy yield, in some cases suppression of digesters foaming and better dewaterability. The full-scale application of disintegration by a lysate-thickening centrifuge was monitored long term in three different WWTPs. The evaluation of contribution of disintegration to biogas production and digested sludge quality was assessed and operational experience is discussed. Increment of specific biogas production was evaluated in the range of 15-26%, organic matter in digested sludge significantly decreased to 48-49%. Results proved that the installation of a disintegrating centrifuge in WWTPs of different sizes and conditions would be useful and beneficial.

Loading and removal of PAHs, fragrance compounds, triclosan and toxicity by composting process from sewage sludge.

PubMed

Ozaki, Noriatsu; Nakazato, Akihiro; Nakashima, Kazuki; Kindaichi, Tomonori; Ohashi, Akiyoshi

2017-12-15

Although the production of compost from sewage sludge is well established in developed countries, the use of sludge-based compost may represent a source of pollutants. The present study assessed the levels of potentially harmful compounds in compost as well as their rates of decrease during composting. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), three fragrance compounds (OTNE, HHCB and AHTN) and triclosan were determined in the initial sewage sludge and in compost over the span of 1year. Simultaneously, the toxicity to luminescent bacteria (Aliivibrio fischeri) and aryl hydrocarbon receptor reactivity of organic solvent extracts of sludge and compost samples were assessed. Higher PAH, fragrance compounds, and triclosan concentrations were found in sewage sludge from urban areas compared with rural regions, and the urban sludge was also more toxic than the rural sludge. The high pollutant concentrations in urban sludge raised the concentrations of these compounds in the raw materials for composting and in the resulting composts. The organic matter was decomposed by 65% during the composting process, and the measured toxic substances were decreased by a similar amount, with the exception of triclosan, which decreased by only 35%. The toxicity to A. fischeri decreased to a greater extent (90%) than did the organic matter, while the aryl hydrocarbon receptor reactivity decreased by only 35%. This lower decrease coincided with that of the aryl hydrocarbon receptor-reactive PAHs (37%). Copyright © 2017 Elsevier B.V. All rights reserved.

Calibration of a complex activated sludge model for the full-scale wastewater treatment plant.

PubMed

Liwarska-Bizukojc, Ewa; Olejnik, Dorota; Biernacki, Rafal; Ledakowicz, Stanislaw

2011-08-01

In this study, the results of the calibration of the complex activated sludge model implemented in BioWin software for the full-scale wastewater treatment plant are presented. Within the calibration of the model, sensitivity analysis of its parameters and the fractions of carbonaceous substrate were performed. In the steady-state and dynamic calibrations, a successful agreement between the measured and simulated values of the output variables was achieved. Sensitivity analysis revealed that upon the calculations of normalized sensitivity coefficient (S(i,j)) 17 (steady-state) or 19 (dynamic conditions) kinetic and stoichiometric parameters are sensitive. Most of them are associated with growth and decay of ordinary heterotrophic organisms and phosphorus accumulating organisms. The rankings of ten most sensitive parameters established on the basis of the calculations of the mean square sensitivity measure (δ(msqr)j) indicate that irrespective of the fact, whether the steady-state or dynamic calibration was performed, there is an agreement in the sensitivity of parameters.

Co-digestion of municipal sludge and external organic wastes for enhanced biogas production under realistic plant constraints.

PubMed

Tandukar, Madan; Pavlostathis, Spyros G

2015-12-15

A bench-scale investigation was conducted to select external organic wastes and mixing ratios for co-digestion with municipal sludge at the F. Wayne Hill Water Resources Center (FWHWRC), Gwinnett County, GA, USA to support a combined heat and power (CHP) project. External wastes were chosen and used subject to two constraints: a) digester retention time no lower than 15 d; and b) total biogas (methane) production not to exceed a specific target level based on air permit constraints on CO2 emissions. Primary sludge (PS), thickened waste activated sludge (TWAS) and digested sludge collected at the FWHWRC, industrial liquid waste obtained from a chewing gum manufacturing plant (GW) and dewatered fat-oil-grease (FOG) were used. All sludge and waste samples were characterized and their ultimate digestibility was assessed at 35 °C. The ultimate COD to methane conversion of PS, TWAS, municipal sludge (PS + TWAS; 40:60 w/w TS basis), GW and FOG was 49.2, 35.2, 40.3, 72.7, and 81.1%, respectively. Co-digestion of municipal sludge with GW, FOG or both, was evaluated using four bench-scale, mesophilic (35 °C) digesters. Biogas production increased significantly and additional degradation of the municipal sludge between 1.1 and 30.7% was observed. Biogas and methane production was very close to the target levels necessary to close the energy deficit at the FWHWRC. Co-digestion resulted in an effluent quality similar to that of the control digester fed only with the municipal sludge, indicating that co-digestion had no adverse effects. Study results prove that high methane production is achievable with the addition of concentrated external organic wastes to municipal digesters, at acceptable higher digester organic loadings and lower retention times, allowing the effective implementation of CHP programs at municipal wastewater treatment plants, with significant cost savings. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sorption of benzimidazole anthelmintics to dissolved organic matter surrogates and sewage sludge.

PubMed

Kim, Hyo-Jung; Lee, Dong Soo; Kwon, Jung-Hwan

2010-06-01

The sorption coefficients of four rarely studied zwitterionic pharmaceuticals (benzimidazoles: fenbendazole, albendazole, thiabendazole and flubendazole) and four metabolites of fenbendazole to various dissolved organic matter surrogates (humic acid, sodium dodecyl sulfate micelle, hydroxypropyl-beta-cyclodextrin and liposomes made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and sewage sludge) were measured to extend the available sorption coefficients and eventually to evaluate their environmental fate in soil and water environment. For the entire range of dissolved organic matters, the more hydrophobic fenbendazole and albendazole had higher sorption coefficients than thiabendazole and flubendazole, indicating that the traditional hypothesis of hydrophobic interaction holds for zwitterionic benzimidazole anthelmintics. However, the sorption coefficients of a given benzimidazole to selected dissolved organic matters (DOMs) varied within an order of magnitude. The measured K(oc) values decreased in the order of fenbendazole, albendazole, thiabendazole and flubendazole for sewage sludge and hydroxypropyl-beta-cyclodextrin whereas the orders were different for the other DOM surrogates, implying the hydrophilic nature of sewage sludge. This was also supported by the (N+O)/C elemental ratio of the sewage sludge sample used in this study. The correlations between log K(oc) and log K(ow) were weak (r(2)=0.28-0.64) and the magnitude of the sorption coefficients to the hydrophilic organic matters (hydroxypropyl-beta-cyclodextrin and sewage sludge) were similar to or slightly smaller than those for the hydrophobic organic matters (humic acids and liposome). This suggests that specific hydrophilic interactions also play a significant role in the sorption of moderately hydrophobic benzimidazoles to organic matters. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Using bioprocess stoichiometry to build a plant-wide mass balance based steady-state WWTP model.

PubMed

Ekama, G A

2009-05-01

Steady-state models are useful for design of wastewater treatment plants (WWTPs) because they allow reactor sizes and interconnecting flows to be simply determined from explicit equations in terms of unit operation performance criteria. Once the overall WWTP scheme is established and the main system defining parameters of the individual unit operations estimated, dynamic models can be applied to the connected unit operations to refine their design and evaluate their performance under dynamic flow and load conditions. To model anaerobic digestion (AD) within plant-wide WWTP models, not only COD and nitrogen (N) but also carbon (C) fluxes entering the AD need to be defined. Current plant-wide models, like benchmark simulation model No 2 (BSM2), impose a C flux at the AD influent. In this paper, the COD and N mass balance steady-state models of activated sludge (AS) organics degradation, nitrification and denitrification (ND) and anaerobic (AD) and aerobic (AerD) digestion of wastewater sludge are extended and linked with bioprocess transformation stoichiometry to form C, H, O, N, chemical oxygen demand (COD) and charge mass balance based models so that also C (and H and O) can be tracked through the whole WWTP. By assigning a stoichiometric composition (x, y, z and a in C(x)H(y)O(z)N(a)) to each of the five main influent wastewater organic fractions and ammonia, these, and the products generated from them via the biological processes, are tracked through the WWTP. The model is applied to two theoretical case study WWTPs treating the same raw wastewater (WW) to the same final sludge residual biodegradable COD. It is demonstrated that much useful information can be generated with the relatively simple steady-state models to aid WWTP layout design and track the different products exiting the WWTP via the solid, liquid and gas streams, such as aerobic versus anaerobic digestion of waste activated sludge, N loads in recycle streams, methane production for energy recovery and green house gas (CO(2), CH(4)) generation. To reduce trial and error usage of WWTP simulation software, it is recommended that they are extended to include pre-processors based on mass balance steady-state models to assist with WWTP layout design, unit operation selection, reactor sizing, option evaluation and comparison and wastewater characterization before dynamic simulation.

Toxicity of ferric chloride sludge to aquatic organisms.

PubMed

Sotero-Santos, Rosana B; Rocha, Odete; Povinelli, Jurandyr

2007-06-01

Iron-rich sludge from a drinking water treatment plant (DWTP) was investigated regarding its toxicity to aquatic organisms and physical and chemical composition. In addition, the water quality of the receiving stream near the DWTP was evaluated. Experiments were carried out in August 1998, February 1999 and May 1999. Acute toxicity tests were carried out on a cladoceran (Daphnia similis), a midge (Chironomus xanthus) and a fish (Hyphessobrycon eques). Chronic tests were conducted only on D. similis. Acute sludge toxicity was not detected using any of the aquatic organisms, but chronic effects were observed upon the fecundity of D. similis. Although there were relatively few sample dates, the results suggested that the DWTP sludge had a negative effect on the receiving body as here was increased suspended matter, turbidity, conductivity, chemical oxygen demand (COD) and hardness in the water downstream of the DWTP effluent discharge. The ferric chloride sludge also exhibited high heavy metal concentrations revealing a further potential for pollution and harmful chronic effects on the aquatic biota when the sludge is disposed of without previous treatment.

Three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy with regional integration analysis for assessing waste sludge hydrolysis treated with multi-enzyme and thermophilic bacteria.

PubMed

Guo, Liang; Lu, Mingmin; Li, Qianqian; Zhang, Jiawen; Zong, Yan; She, Zonglian

2014-11-01

The hydrolysis effect of waste sludge after multi-enzyme and thermophilic bacteria pretreatments is investigated using excitation-emission matrix (EEM) with fluorescence regional integration (FRI) in this study. The compositional characteristics of extracellular polymeric substances (EPS) and dissolved organic matters (DOM) were analyzed to evaluate the sludge disintegration. The EPS and cell wall in sludge were disrupted after hydrolysis which led to carbohydrate, protein and soluble chemical oxygen demand (SCOD) of DOM increasing in sludge supernatant. The bio-degradability level in the extracted fractions of EPS and DOM depending on the fluorescence zones was found after hydrolysis. The highest proportion of percent fluorescence response (Pi,n) in EPS and DOM was soluble microbial by-product and humic acid-like organics. A significant increase of humic acid-like organics in DOM after thermophilic bacteria hydrolysis was obtained. The assessment of hydrolysis using EEM coupled with FRI provided a new insight toward the bio-utilization process of waste sludge. Copyright © 2014 Elsevier Ltd. All rights reserved.

Improved methane production from waste activated sludge with low organic content by alkaline pretreatment at pH 10.

PubMed

Feng, L Y; Yang, L Q; Zhang, L X; Chen, H L; Chen, J

2013-01-01

Sludge with low organic content always results in an unsatisfactory performance, even failure of anaerobic digestion. The alkaline pretreatment effect on anaerobic digestion of sludge with low organic content has seldom been studied although it gives many benefits for sludge with high organic content. In this study the influence of alkaline pretreatment (pH 10, an effective alkaline pH) on the solubilization and methane production from waste activated sludge (WAS) with low organic content was investigated. Results from biochemical methane potential (BMP) experiments showed that anaerobic biodegradability of WAS was greatly improved by alkaline pretreatment at pH 10. Methane production from the current WAS under conditions of pretreatment time 4 h and digestion time 15 d was 139.6 mL/g VS (volatile solids), much higher than that from the unpretreated WAS with digestion time of 20 d (75.2 mL/g VS). Also, the solubilization of WAS was significantly accelerated by alkaline pretreatment. Mechanism exploration indicated that the general activities of anaerobic microorganisms, specific activities of key enzymes and the amounts of methanogens were enhanced by alkaline pretreatment at pH 10, showing good agreement with methane production.

Tracing the evolution of degraders in activated sludge during the sludge’s acclimation to a xenobiotic organic

NASA Astrophysics Data System (ADS)

Chong, N. M.; Fan, C. H.; Yang, Y. C.

2017-01-01

The molecular biology method of high-throughput pyrosequencing was employed to examine the change of activated sludge community structures during the process in which activated sludge was acclimated to and degraded a target xenobiotic. The sample xenobiotic organic compound used as the activated sludge acclimation target was the herbicide 2,4-dichlorphenoxyacetic acid (2,4-D). Indigenous activated sludge microorganisms were acclimated to 2,4-D as the sole carbon source in both the batch and the continuous-flow reaction modes. Sludge masses at multiple time points during the course of acclimation were subjected to pyrosequencing targeting the microorganisms’ 16S rRNA genes. With the bacterial 16S rRNA sequencing results the genera that increased in abundance were checked with degradative pathway databases or literature to confirm that they are commonly seen as potent degraders of 2,4-D. From this systematic examination of degrader changes at time points during activated sludge acclimation and degradation of the target xenobiotic, the trend of degrader evolution in activated sludge over the sludge’s acclimation process to a xenobiotic was traced.

Combination of alkaline and microwave pretreatment for disintegration of meat processing wastewater sludge.

PubMed

Erden, G

2013-01-01

Meat processing wastewater sludge has high organic content but it is very slow to degrade in biological processes. Anaerobic digestion may be a good alternative for this type of sludge when the hydrolysis, known to be the rate-limiting step of biological sludge anaerobic degradation, could be eliminated by disintegration. This investigation deals with disintegration of meat processing wastewater sludge. Microwave (MW) irradiation and combined alkaline pretreatment and MW irradiation were applied to sludge for disintegration purposes. Disintegration performance of the methods was evaluated with disintegration degree based on total and dissolved organic carbon calculations (DD(TOC)), and the solubilization of volatile solids (S(VS)) in the pretreated sludge. Optimum conditions were found to be 140 degrees C and 30 min for MW irradiation using response surface methodology (RSM) and pH = 13 for combined pretreatment. While DD(TOC) was observed as 24.6% and 54.9, S(VS) was determined as 8.54% and 42.5% for MW pretreated and combined pretreated sludge, respectively. The results clearly show that pre-conditioning of sludge with alkaline pretreatment played an important role in enhancing the disintegration efficiency of subsequent MW irradiation. Disintegration methods also affected the anaerobic biodegradability and dewaterability of sludge. An increase of 23.6% in biogas production in MW irradiated sludge was obtained, comparing to the raw sludge at the end of the 35 days of incubation. This increase was observed as 44.5% combined pretreatment application. While MW pretreatment led to a little improvement of the dewatering performance of sludge, in combined pretreatment NaOH deteriorates the sludge dewaterability.

Pretreatment of high solid microbial sludges

DOEpatents

Rivard, C.J.; Nagle, N.J.

1998-07-28

A process and apparatus are disclosed for pretreating microbial sludges in order to enhance secondary anaerobic digestion. The pretreatment process involves disrupting the cellular integrity of municipal sewage sludge through a combination of thermal, explosive decompression and shear forces. The sludge is pressurized and pumped to a pretreatment reactor where it is mixed with steam to heat and soften the sludge. The pressure of the sludge is suddenly reduced and explosive decompression forces are imparted which partially disrupt the cellular integrity of the sludge. Shear forces are then applied to the sludge to further disrupt the cellular integrity of the sludge. Disrupting cellular integrity releases both soluble and insoluble organic constituents and thereby renders municipal sewage sludge more amenable to secondary anaerobic digestion. 1 fig.

FY2000 FRED Test Report - Final Report on the Crossflow Filter Optimization with 5.6M Sodium Salt Solution

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

Poirier, M.R.

2001-04-04

The Filtration Research Engineering Demonstration (FRED) at the University of South Carolina ran a test campaign to confirm the utility of crossflow filtration for use with the MST sorption as a strontium-actinide removal technology that is expected to be coupled with the ion exchange and solvent extraction process alternatives. FRED has a Mott Metallurgical 7 tube filter with individual tubes 10 ft long and 3/4 inch o.d. having a nominal pore size of 0.5 microns. The blend sludge consisted of a 50/50 wt percent mixture of sludge simulants of SRS Tank 40H and Tank 8F simulated sludges previously manufactured atmore » FRED. Monosodium Titanate (MST) was blended with the 50/50 sludge mixture in a proportion of 0.9167 MST-to-Sludge ratio to provide the solids loadings analyzed in this test.« less

Aerobic granular sludge: a promising technology for decentralised wastewater treatment.

PubMed

Li, Z H; Kuba, T; Kusuda, T

2006-01-01

In order to evaluate the characteristics of aerobic granular sludge, a sequencing batch reactor, feeding with synthetic wastewater at the organic loading rate of 8 kg COD/m3 d, was employed on the laboratory scale. Granules occurred in the reactor within 1 week after the inoculation from conventional flocculent sludge. Aerobic granular sludge was characterised by the outstanding settling properties and considerable contaminates removal efficiencies. The SVI30 values were in the range of 20 to 40 ml g(-1). However, the sludge volume index of short settling time (e.g. SVI10--10 min) is suggested to describe the fast settling properties of aerobic granular sludge. The potential application in the decentralised system is evaluated from the point view of footprint and high bioactivity. The occurrence of sloughing, resulting from the outgrowth of filamentous organisms, would be responsible for the instability of aerobic granules. The starvation phase should therefore be carefully controlled for the maintenance and stability of aerobic granular sludge system.

The influence of redox chemistry and pH on chemically active forms of arsenic in sewage sludge-amended soil

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

Carbonell-Barrachina, A.; Jugsujinda, A.; DeLaune, R.D.

1999-07-01

Chemical fractionation procedures were used to quantify the effect of the sediment redox and pH conditions on the adsorption and solubility of arsenic (As) in municipal sewage sludge and sewage sludge-amended soil. Sludge and sludge-amended soil were incubated in microcosms in which Eh-pH conditions were controlled. Samples were sequentially extracted to determine As in various chemical forms (water soluble, exchangeable, bound to carbonates, bound to iron (Fe) and manganese (Mn) oxides, bound to insoluble organics and sulfides) and the chemically inactive fraction (mineral residues). In both sewage sludge and sludge-amended soil, As chemistry was governed by large molecular humic mattermore » and sulfides and Fe and Mn-oxides. Solubility of As remained low and constant under both aerobic and anaerobic conditions in sludge-amended soil. After dissolution of Fe and Mn-oxides, As{sup 5+} was released into sludge solution, reduced to As{sup 3+} and likely precipitated as sulfide. Therefore, an organic amendment rich in sulfur compounds, such as sewage sludge, would drastically reduce the potential risks derived from As pollution under highly anoxic conditions by precipitation of this toxic metalloid as insoluble and immobile sulfides.« less

Consequences of sludge composition on combustion performance derived from thermogravimetry analysis.

PubMed

Li, Meiyan; Xiao, Benyi; Wang, Xu; Liu, Junxin

2015-01-01

Wastewater treatment plants produce millions of tons of sewage sludge. Sewage sludge is recognized as a promising feedstock for power generation via combustion and can be used for energy crisis adaption. We aimed to investigate the quantitative effects of various sludge characteristics on the overall sludge combustion process performance. Different types of sewage sludge were derived from numerous wastewater treatment plants in Beijing for further thermogravimetric analysis. Thermogravimetric-differential thermogravimetric curves were used to compare the performance of the studied samples. Proximate analytical data, organic compositions, elementary composition, and calorific value of the samples were determined. The relationship between combustion performance and sludge composition was also investigated. Results showed that the performance of sludge combustion was significantly affected by the concentration of protein, which is the main component of volatiles. Carbohydrates and lipids were not correlated with combustion performance, unlike protein. Overall, combustion performance varied with different sludge organic composition. The combustion rate of carbohydrates was higher than those of protein and lipid, and carbohydrate weight loss mainly occurred during the second stage (175-300°C). Carbohydrates have a substantial effect on the rate of system combustion during the second stage considering the specific combustion feature. Additionally, the combustion performance of digested sewage sludge is more negative than the others. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cost minimization in a full-scale conventional wastewater treatment plant: associated costs of biological energy consumption versus sludge production.

PubMed

Sid, S; Volant, A; Lesage, G; Heran, M

2017-11-01

Energy consumption and sludge production minimization represent rising challenges for wastewater treatment plants (WWTPs). The goal of this study is to investigate how energy is consumed throughout the whole plant and how operating conditions affect this energy demand. A WWTP based on the activated sludge process was selected as a case study. Simulations were performed using a pre-compiled model implemented in GPS-X simulation software. Model validation was carried out by comparing experimental and modeling data of the dynamic behavior of the mixed liquor suspended solids (MLSS) concentration and nitrogen compounds concentration, energy consumption for aeration, mixing and sludge treatment and annual sludge production over a three year exercise. In this plant, the energy required for bioreactor aeration was calculated at approximately 44% of the total energy demand. A cost optimization strategy was applied by varying the MLSS concentrations (from 1 to 8 gTSS/L) while recording energy consumption, sludge production and effluent quality. An increase of MLSS led to an increase of the oxygen requirement for biomass aeration, but it also reduced total sludge production. Results permit identification of a key MLSS concentration allowing identification of the best compromise between levels of treatment required, biological energy demand and sludge production while minimizing the overall costs.

Behavior of radioactive materials and safety stock of contaminated sludge.

PubMed

Tsushima, Ikuo

2017-01-28

The radioactive fallout from the Fukushima Dai-ichi nuclear power plant disaster in 2011 has flowed into and accumulated in many wastewater treatment plants (WWTPs) via sewer systems; this has had a negative impact on WWTPs in eastern Japan. The behavior of radioactive materials was analyzed at four WWTPs in the Tohoku and Kanto regions to elucidate the mechanism by which radioactive materials are concentrated during the sludge treatment process from July 2011 to March 2013. Furthermore, numerical simulations were conducted to study the safe handling of contaminated sewage sludge stocked temporally in WWTPs. Finally, a dissolution test was conducted by using contaminated incinerated ash and melted slag derived from sewage sludge to better understand the disposal of contaminated sewage sludge in landfills. Measurements indicate that a large amount of radioactive material accumulates in aeration tanks and is becoming trapped in the concentrated sludge during the sludge condensation process. The numerical simulation indicates that a worker's exposure around contaminated sludge is less than 1 µSv/h when maintaining an isolation distance of more than 10 m, or when shielding with more than 20-cm-thick concrete. The radioactivity level of the eluate was undetectable in 9 out of 12 samples; in the remaining three samples, the dissolution rates were 0.5-2.7%.

Reduced temperature hydrolysis at 134 °C before thermophilic anaerobic digestion of waste activated sludge at increasing organic load.

PubMed

Gianico, A; Braguglia, C M; Cesarini, R; Mininni, G

2013-09-01

The performance of thermophilic digestion of waste activated sludge, either untreated or thermal pretreated, was evaluated through semi-continuous tests carried out at organic loading rates in the range of 1-3.7 kg VS/m(3)d. Although the thermal pretreatment at T=134 °C proved to be effective in solubilizing organic matter, no significant gain in organics degradation was observed. However, the digestion of pretreated sludge showed significant soluble COD removal (more than 55%) whereas no removal occurred in control reactors. The lower the initial sludge biodegradability, the higher the efficiency of thermal pretreated digestion was observed, in particular as regards higher biogas and methane production rates with respect to the parallel untreated sludge digestion. Heat balance of the combined thermal hydrolysis/thermophilic digestion process, applied on full-scale scenarios, showed positive values for direct combustion of methane. In case of combined heat and power generation, attractive electric energy recoveries were obtained, with a positive heat balance at high load. Copyright © 2013. Published by Elsevier Ltd.

Direct oxygen uptake from air by novel glycogen accumulating organism dominated biofilm minimizes excess sludge production.

PubMed

Hossain, Md Iqbal; Paparini, Andrea; Cord-Ruwisch, Ralf

2018-05-29

The cost associated with treatment and disposal of excess sludge produced is one of the greatest operational expenses in wastewater treatment plants. In this study, we quantify and explain greatly reduced excess sludge production in the novel glycogen accumulating organism (GAO) dominated drained biofilm system previously shown to be capable of extremely energy efficient removal of organic carbon (biological oxygen demand or BOD) from wastewater. The average excess sludge production rate was 0.05 g VSS g -1 BOD (acetate) removed, which is about 9-times lower than that of comparative studies using the same acetate based synthetic wastewater. The substantially lower sludge yield was attributed to a number of features such as the high oxygen consumption facilitated by direct oxygen uptake from air, high biomass content (21.41 g VSS L -1 of reactor), the predominance of the GAO (Candidatus competibacter) with a low growth yield and the overwhelming presence of the predatory protozoa (Tetramitus) in the biofilm. Overall, the combination of low-energy requirement for air supply (no compressed air supply) and the low excess sludge production rate, could make this novel "GAO drained biofilm" process one of the most economical ways of biological organic carbon removal from wastewater. Copyright © 2018. Published by Elsevier B.V.

Use of wastewater ER sludges for the immobilization of heavy metals

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

Macha, S.; Murray, D.; Urasa, I.T.

1996-10-01

The distribution, mobility, and bioavailability of heavy metals in soils, surface water, and ground water have been of major interest and concern from both environmental and geochemical standpoints. Wastewater sludges represent an important anthropogenic factor whose impact on these processes is not fully understood. In the past, incineration and landfilling were common practices for discarding wastewater sludges. However, as local and state laws governing the disposal of these materials have become more stringent, land application has been used as an alternative. Reported studies have shown that the impact of land application of sludges can vary widely and is influenced bymore » a number of factors, including the source of the sludge; the organic matter content of the sludge; the form in which the sludge is applied; and the prevailing conditions of the receiving soils. It has also been shown that sewage sludge can have solubilizing effects on solid-phase heavy metals, thereby causing geochemical shifts of the insoluble fractions of metals to the more soluble forms. The work presented in this paper utilized synthetic minerals, standard solutions, sludges, and agricultural soils obtained from different sources to determine the mechanisms involved in the mineralization of heavy metals by sludge; the influence of soil conditions; interelemental effects; the influence of natural organic matter; and possible microbial activity that may come into play. Several types of sludge were evaluated for lead binding capacity.« less

Sorption and biodegradability of sludge bacterial extracellular polymers in soil and their influence on soil copper behavior.

PubMed

Zhou, L X; Zhou, S G; Zhan, X H

2004-01-01

Bacterial extracellular polymers (BEP) affect the translocation and fate of organic and inorganic pollutants in terrestrial and aquatic ecosystems. In this study, BEP from activated sludge was compared with sludge dissolved organic matter (DOM) in terms of behavior and effects on the mobilization and bioavailability of Cu in a well-aged Cu-contaminated orchard sandy loam. Addition of sludge BEP (10-200 mg dissolved organic carbon [DOC] L(-1)) to the soil resulted in 1.6- to 12.8-fold-higher soil soluble Cu concentration over the control and 1.3- to 2.2-fold over sludge DOM of the same concentration. Consequently, the Cu uptake by the ryegrass (Lolium perenne L., cv. Target) grown in the soil was increased by 31% due to interval watering of 100 mg DOC L(-1) of sludge BEP solution in a 35-d period. The influence of sludge BEP on mobilizing soil Cu could be maintained as long as 60 d or more, depending on BEP biodegradation status. The findings that sludge BEP promoted Cu mobilization and bioavailability could be attributed to less adsorption of BEP by soil, slow degradation, and higher affinity with Cu. For example, after 3 wk of aerobic incubation, the soluble Cu present in the sludge DOM-treated soil was reduced to about the level of the control, while the concentration of soluble Cu in BEP-treated soil was 6.2 times higher than that in the control. Therefore, sludge BEP could act as a facilitated-transport carrier of Cu. The environmental risk of Cu should receive much attention if BEP is incorporated into soils.

Linear alkylbenzenes as tracers of sewage-sludge-derived inputs of organic matter, PCBs, and PAHs to sediments at the 106-mile deep water disposal site

USGS Publications Warehouse

Lamoureux, E.M.; Brownawell, Bruce J.; Bothner, Michael H.

1996-01-01

Linear alkylbenzenes (LABs) are sensitive source-specific tracers of sewage inputs to the marine environment. Because they are highly particle reactive and nonspecifically sorbed to organic matter, LABs are potential tracers of the transport of both sludge-derived organic matter and other low solubility hydrophobic contaminants (e.g., PCBs and PAHs); sediment trap studies at the 106-Mile Site have shown LABs to be valuable in testing models of sludge deposition to the sea floor. In this study we report on the distributions of LABs, PCBs, PAHs, and Ag in surface sediments collected within a month of the complete cessation of dumping (July, 1992) in the vicinity of the dump site. Total LAB concentrations were lower than those measured by Takada and coworkers in samples from nearby sites collected in 1989. LABs from both studies appear to be significantly depleted (6 to 25-fold) in surface sediments relative to excess Ag (another sludge tracer) when compared to sewage sludge and sediment trap compositions. Comparison of LAB sediment inventories to model predictions of sludge particle fluxes supports the contention that LABs have been lost from the bed. The use of LABs to examine the short-or long-term fate of sludge derived materials in deep-sea sediments should be questioned. The causes of this LAB depletion are unclear at this point, and we discuss several hypotheses. The concentrations of total PCBs and PAHs are both correlated with sludge tracers, suggesting that there may be a measurable contribution of sludge-derived inputs on top of other nonpoint sources of these contaminant classes. This possibility is consistent with the composition of these contaminants determined in recent and historical analyses of sewage sludge.

The Ruhrverband sewage sludge disposal concept in the conflict between European and German standards and regulations.

PubMed

Evers, P; Schmitt, F; Albrecht, D R; Jardin, N

2005-01-01

The Ruhrverband, acting as a water association responsible for integrated water resources management within the entire natural river basin of the Ruhr, operates a network of 83 wastewater treatment plants (WWTPs) and connected sludge disposal facilities. According to German regulations, the disposal of sewage sludge containing more than 5% of organic dry solids will be prohibited as of 1 June 2005. In Germany, the only future alternative to incineration will be the agricultural utilization of sludge. However, this way of sludge disposal is presently the subject of critical discussions in Germany because of the organic and inorganic toxic substances, which may be contained in sewage sludge, despite the fact that very stringent standards are to be met by agricultural uses. On the other hand, application of sewage sludge to agricultural land is explicitly supported by the European Sewage Sludge Directive 86/278/EEC. In the face of this controversial situation the Ruhrverband has initiated, in 2000, the development of a comprehensive and sustainable sludge and waste disposal concept for all wastewater facilities it operates in the entire Ruhr River Basin. The concept includes de-central sludge digestion and dewatering and subsequent transport to two central sludge incineration plants. It is expected that in future not more than 5% of all sludges produced in Ruhrverband's WWTPs will be used in agriculture. That means, the major part of 95% will have to be incinerated.

Effect of low temperature thermal pre-treatment on the solubilization of organic matter, pathogen inactivation and mesophilic anaerobic digestion of poultry sludge.

PubMed

Ruiz-Espinoza, Juan E; Méndez-Contreras, Juan M; Alvarado-Lassman, Alejandro; Martínez-Delgadillo, Sergio A

2012-01-01

Treatment of poultry industry effluents produces wastewater sludge with high levels of organic compounds and pathogenic microorganisms. In this research, the thermal pre-treatment of poultry slaughterhouse sludge (PSS) was evaluated for low temperatures in combination with different exposure times as a pre-hydrolysis strategy to improve the anaerobic digestion process. Organic compounds solubilization and inactivation of pathogenic microorganisms were evaluated after treatment at 70, 80 or 90°C for 30, 60 or 90 min. The results showed that 90°C and 90 min were the most efficient conditions for solubilization of the organic compounds (10%). In addition, the bacteria populations and the more resistant structures, such as helminth eggs (HE), were completely inactivated. Finally, the thermal pre-treatment applied to the sludge increased methane yield by 52% and reduced hydraulic retention time (HRT) by 52%.

Co-biodrying of sewage sludge and organic fraction of municipal solid waste: Role of mixing proportions.

PubMed

Zhang, Difang; Luo, Wenhai; Yuan, Jing; Li, Guoxue

2018-04-26

This study investigated the performance of co-biodrying sewage sludge and organic fraction of municipal solid waste (OFMSW) at different proportions. Cornstalk was added at 15% (of total wet weight) as the bulking agent. Results show that increasing OFMSW percentage promoted the biodegradation of organic matter, thus enhancing the temperature integration value and water removal to above 75% during sludge and OFMSW co-biodrying. In particular, adding more OFMSW accelerated the biodegradation of soluble carbohydrates, lignins, lipids, and amylums, resulting in more organic loss and thus lower biodrying index (3.3-3.7 for 55-85% OFMSW). Water balance calculation indicated that evaporation was the main mechanism for water removal. Heat used for water evaporation was 37.7-48.6% of total heat consumption during co-biodrying. Our results suggest that sludge and OFMSW should be mixed equally for their efficient co-biodrying. Copyright © 2018 Elsevier Ltd. All rights reserved.

Some properties of a granular activated carbon-sequencing batch reactor (GAC-SBR) system for treatment of textile wastewater containing direct dyes.

PubMed

Sirianuntapiboon, Suntud; Sadahiro, Ohmomo; Salee, Paneeta

2007-10-01

Resting (living) bio-sludge from a domestic wastewater treatment plant was used as an adsorbent of both direct dyes and organic matter in a sequencing batch reactor (SBR) system. The dye adsorption capacity of the bio-sludge was not increased by acclimatization with direct dyes. The adsorption of Direct Red 23 and Direct Blue 201 onto the bio-sludge was almost the same. The resting bio-sludge showed higher adsorption capacity than the autoclaved bio-sludge. The resting bio-sludge that was acclimatized with synthetic textile wastewater (STWW) without direct dyes showed the highest Direct Blue 201, COD, and BOD(5) removal capacities of 16.1+/-0.4, 453+/-7, and 293+/-9 mg/g of bio-sludge, respectively. After reuse, the dye adsorption ability of deteriorated bio-sludge was recovered by washing with 0.1% sodium dodecyl sulfate (SDS) solution. The direct dyes in the STWW were also easily removed by a GAC-SBR system. The dye removal efficiencies were higher than 80%, even when the system was operated under a high organic loading of 0.36kgBOD(5)/m(3)-d. The GAC-SBR system, however, showed a low direct dye removal efficiency of only 57+/-2.1% with raw textile wastewater (TWW) even though the system was operated with an organic loading of only 0.083kgBOD(5)/m(3)-d. The dyes, COD, BOD(5), and total kjeldalh nitrogen removal efficiencies increased up to 76.0+/-2.8%, 86.2+/-0.5%, 84.2+/-0.7%, and 68.2+/-2.1%, respectively, when 0.89 g/L glucose (organic loading of 0.17kgBOD(5)/m(3)-d) was supplemented into the TWW.

A study on using fireclay as a biomass carrier in an activated sludge system.

PubMed

Tilaki, Ramazan Ali Dianati

2011-01-01

By adding a biomass carrier to an activated sludge system, the biomass concentration will increase, and subsequently the organic removal efficiency will be enhanced. In this study, the possibility of using excess sludge from ceramic and tile manufacturing plants as a biomass carrier was investigated. The aim of this study was to determine the effect of using fireclay as a biomass carrier on biomass concentration, organic removal and nitrification efficiency in an activated sludge system. Experiments were conducted by using a bench scale activated sludge system operating in batch and continuous modes. Artificial simulated wastewater was made by using recirculated water in a ceramic manufacturing plant. In the continuous mode, hydraulic detention time in the aeration reactor was 8 and 22 h. In the batch mode, aeration time was 8 and 16 h. Fireclay doses were 500, 1,400 and 2,250 mg l(-1), and were added to the reactors in each experiment separately. The reactor with added fireclay was called a Hybrid Biological Reactor (HBR). A reactor without added fireclay was used as a control. Efficiency parameters such as COD, MLVSS and nitrate were measured in the control and HBR reactors according to standard methods. The average concentration of biomass in the HBR reactor was greater than in the control reactor. The total biomass concentration in the HBR reactor (2.25 g l(-1) fireclay) in the continuous mode was 3,000 mg l(-1) and in the batch mode was 2,400 mg l(-1). The attached biomass concentration in the HBR reactor (2.25 g l(-1) fireclay) in the continuous mode was 1,500 mg l(-1) and in the batch mode was 980 mg l(-1). Efficiency for COD removal in the HBR and control reactor was 95 and 55%, respectively. In the HBR reactor, nitrification was enhanced, and the concentration of nitrate was increased by 80%. By increasing the fireclay dose, total and attached biomass was increased. By adding fireclay as a biomass carrier, the efficiency of an activated sludge system to treat wastewater from ceramic manufacturing plants was increased.

Kinetic model of excess activated sludge thermohydrolysis.

PubMed

Imbierowicz, Mirosław; Chacuk, Andrzej

2012-11-01

Thermal hydrolysis of excess activated sludge suspensions was carried at temperatures ranging from 423 K to 523 K and under pressure 0.2-4.0 MPa. Changes of total organic carbon (TOC) concentration in a solid and liquid phase were measured during these studies. At the temperature 423 K, after 2 h of the process, TOC concentration in the reaction mixture decreased by 15-18% of the initial value. At 473 K total organic carbon removal from activated sludge suspension increased to 30%. It was also found that the solubilisation of particulate organic matter strongly depended on the process temperature. At 423 K the transfer of TOC from solid particles into liquid phase after 1 h of the process reached 25% of the initial value, however, at the temperature of 523 K the conversion degree of 'solid' TOC attained 50% just after 15 min of the process. In the article a lumped kinetic model of the process of activated sludge thermohydrolysis has been proposed. It was assumed that during heating of the activated sludge suspension to a temperature in the range of 423-523 K two parallel reactions occurred. One, connected with thermal destruction of activated sludge particles, caused solubilisation of organic carbon and an increase of dissolved organic carbon concentration in the liquid phase (hydrolysate). The parallel reaction led to a new kind of unsolvable solid phase, which was further decomposed into gaseous products (CO(2)). The collected experimental data were used to identify unknown parameters of the model, i.e. activation energies and pre-exponential factors of elementary reactions. The mathematical model of activated sludge thermohydrolysis appropriately describes the kinetics of reactions occurring in the studied system. Copyright © 2012 Elsevier Ltd. All rights reserved.

Predicting concentrations of trace organic compounds in municipal wastewater treatment plant sludge and biosolids using the PhATE™ model.

PubMed

Cunningham, Virginia L; D'Aco, Vincent J; Pfeiffer, Danielle; Anderson, Paul D; Buzby, Mary E; Hannah, Robert E; Jahnke, James; Parke, Neil J

2012-07-01

This article presents the capability expansion of the PhATE™ (pharmaceutical assessment and transport evaluation) model to predict concentrations of trace organics in sludges and biosolids from municipal wastewater treatment plants (WWTPs). PhATE was originally developed as an empirical model to estimate potential concentrations of active pharmaceutical ingredients (APIs) in US surface and drinking waters that could result from patient use of medicines. However, many compounds, including pharmaceuticals, are not completely transformed in WWTPs and remain in biosolids that may be applied to land as a soil amendment. This practice leads to concerns about potential exposures of people who may come into contact with amended soils and also about potential effects to plants and animals living in or contacting such soils. The model estimates the mass of API in WWTP influent based on the population served, the API per capita use, and the potential loss of the compound associated with human use (e.g., metabolism). The mass of API on the treated biosolids is then estimated based on partitioning to primary and secondary solids, potential loss due to biodegradation in secondary treatment (e.g., activated sludge), and potential loss during sludge treatment (e.g., aerobic digestion, anaerobic digestion, composting). Simulations using 2 surrogate compounds show that predicted environmental concentrations (PECs) generated by PhATE are in very good agreement with measured concentrations, i.e., well within 1 order of magnitude. Model simulations were then carried out for 18 APIs representing a broad range of chemical and use characteristics. These simulations yielded 4 categories of results: 1) PECs are in good agreement with measured data for 9 compounds with high analytical detection frequencies, 2) PECs are greater than measured data for 3 compounds with high analytical detection frequencies, possibly as a result of as yet unidentified depletion mechanisms, 3) PECs are less than analytical reporting limits for 5 compounds with low analytical detection frequencies, and 4) the PEC is greater than the analytical method reporting limit for 1 compound with a low analytical detection frequency, possibly again as a result of insufficient depletion data. Overall, these results demonstrate that PhATE has the potential to be a very useful tool in the evaluation of APIs in biosolids. Possible applications include: prioritizing APIs for assessment even in the absence of analytical methods; evaluating sludge processing scenarios to explore potential mitigation approaches; using in risk assessments; and developing realistic nationwide concentrations, because PECs can be represented as a cumulative probability distribution. Finally, comparison of PECs to measured concentrations can also be used to identify the need for fate studies of compounds of interest in biosolids. Copyright © 2011 SETAC.

Simultaneous Cr(VI) bio-reduction and methane production by anaerobic granular sludge.

PubMed

Hu, Qian; Sun, Jiaji; Sun, Dezhi; Tian, Lan; Ji, Yanan; Qiu, Bin

2018-08-01

Wastewater containing toxic hexavalent chromium (Cr(VI)) were treated with well-organized anaerobic granular sludge in this study. Results showed that the anaerobic granular sludge rapidly removed Cr(VI), and 2000 µg·L -1 Cr(VI) was completely eliminated within 6 min, which was much faster than the reported duration of removal by reported artificial materials. Sucrose added as a carbon source acted as an initial electron donor to reduce Cr(VI) to Cr(III). This process was considered as the main mechanism of Cr(VI) removal. Methane production by anaerobic granular sludge was improved by the addition of Cr(VI) at a concentration lower than 500 µg·L -1 . Anaerobic granular sludge had a well-organized structure, which presented good resistance against toxic Cr(VI). Trichoccus accelerated the degradation of organic substances to generate acetates with a low Cr(VI) concentration, thereby enhancing methane production by acetotrophic methanogens. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stabilizing cadmium into aluminate and ferrite structures: Effectiveness and leaching behavior.

PubMed

Su, Minhua; Shih, Kaimin; Kong, Lingjun

2017-02-01

The inappropriate disposal of sludge, particularly for those enriched in heavy metals, is highly hazardous to the environment. Thermally converting sludge into useful products is a highly promising technique as heavy metals are immobilized and organic substances are mineralized. This work investigated the feasibility of stabilizing simulated cadmium-laden sludge by sintering with Al-and Fe-rich precursors. To simulate the process, cadmium oxide was alternatively mixed and sintered with γ-Al 2 O 3 and α-Fe 2 O 3 . Cadmium was crystallographically incorporated into aluminate (CdAl 4 O 7 ) monoclinic structure and ferrite (CdFe 2 O 4 ) spinel, dependent on the type of precursor used. The CdFe 2 O 4 formation was initialed at about 150-300 °C lower than that of CdAl 4 O 7 . With Rietveld refinement analysis of the collated XRD data, the weight percentages of crystalline phases in the fired samples were quantified. To evaluate the cadmium incorporation efficiency, a transformation ratio (TR) index was devised. The TR values revealed that, to effectively incorporate cadmium, 950 °C was favored by γ-Al 2 O 3 and 850 °C was for α-Fe 2 O 3 within a 3-h sintering treatment. Constant pH leaching test (CPLT) was used to assess the metal stabilization effects, revealing a remarkable reduction of cadmium by transformation into CdAl 4 O 7 and CdFe 2 O 4 . Both CdAl 4 O 7 and CdFe 2 O 4 were incongruently dissolved in an acid solution. The overall finding indicated a potentially feasible technology in cadmium-laden sludge stabilization. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of aeration strategy on the evolution of dissolved organic matter (DOM) and microbial community structure during sludge bio-drying.

PubMed

Zhang, Junya; Cai, Xing; Qi, Lu; Shao, Chunyan; Lin, Yang; Zhang, Jin; Zhang, Yuanli; Shen, Peihong; Wei, Yuansong

2015-09-01

Sludge bio-drying in which sludge is dried by means of the heat generated by the aerobic degradation of its own organic substances has been widely used for sludge treatment. A better understanding of the evolution of dissolved organic matter (DOM) and its degradation drivers during sludge bio-drying could facilitate its control. Aeration is one of the key factors that affect sludge bio-drying performance. In this study, two aeration strategies (pile I-the optimized and pile II-the current) were established to investigate their impacts on the evolution of DOM and the microbial community in a full-scale sludge bio-drying plant. A higher pile temperature in pile I caused pile I to enter the DOM and microbiology stable stage approximately2 days earlier than pile II. The degradation of easily degradable components in the DOM primarily occurred in the thermophilic phase; after that degradation, the DOM components changed a little. Along with the evolution of the DOM, its main degradation driver, the microbial community, changed considerably. Phyla Firmicutes and Proteobacteria were dominant in the thermophilic stage, and genus Ureibacillus, which was the primary thermophilic bacteria, was closely associated with the degradation of the DOM. In the mesophilic stage, the microbial community changed significantly at first and subsequently stabilized, and the genus Parapedobacter, which belongs to Bacteriodetes, became dominant. This study elucidates the interplay between the DOM and microbial community during sludge bio-drying.

Persistence of pathogenic prion protein during simulated wastewater treatment processes

USGS Publications Warehouse

Hinckley, G.T.; Johnson, C.J.; Jacobson, K.H.; Bartholomay, C.; Mcmahon, K.D.; McKenzie, D.; Aiken, Judd M.; Pedersen, J.A.

2008-01-01

Transmissible spongiform encephalopathies (TSEs, prion diseases) are a class of fatal neurodegenerative diseases affecting a variety of mammalian species including humans. A misfolded form of the prion protein (PrP TSE) is the major, if not sole, component of the infectious agent. Prions are highly resistant to degradation and to many disinfection procedures suggesting that, if prions enter wastewater treatment systems through sewers and/or septic systems (e.g., from slaughterhouses, necropsy laboratories, rural meat processors, private game dressing) or through leachate from landfills that have received TSE-contaminated material, prions could survive conventional wastewater treatment Here, we report the results of experiments examining the partitioning and persistence of PrPTSE during simulated wastewater treatment processes including activated and mesophilic anaerobic sludge digestion. Incubation with activated sludge did not result in significant PrPTSE degradation. PrPTSE and prion infectivity partitioned strongly to activated sludge solids and are expected to enter biosolids treatment processes. A large fraction of PrPTSE survived simulated mesophilic anaerobic sludge digestion. The small reduction in recoverable PrPTSE after 20-d anaerobic sludge digestion appeared attributable to a combination of declining extractability with time and microbial degradation. Our results suggest that if prions were to enter municipal wastewater treatment systems, most would partition to activated sludge solids, survive mesophilic anaerobic digestion, and be present in treated biosolids. ?? 2008 American Chemical Society.

40 CFR 503.41 - Special definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... device in which organic matter and inorganic matter in sewage sludge are combusted in a bed of particles... combustion of organic matter and inorganic matter in sewage sludge by high temperatures in an enclosed device... accordance with 40 CFR 51.100 (ii). (p) Total hydrocarbons means the organic compounds in the exit gas from a...

40 CFR 503.41 - Special definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... device in which organic matter and inorganic matter in sewage sludge are combusted in a bed of particles... combustion of organic matter and inorganic matter in sewage sludge by high temperatures in an enclosed device... accordance with 40 CFR 51.100 (ii). (p) Total hydrocarbons means the organic compounds in the exit gas from a...

40 CFR 503.41 - Special definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... device in which organic matter and inorganic matter in sewage sludge are combusted in a bed of particles... combustion of organic matter and inorganic matter in sewage sludge by high temperatures in an enclosed device... accordance with 40 CFR 51.100 (ii). (p) Total hydrocarbons means the organic compounds in the exit gas from a...

40 CFR 503.41 - Special definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... device in which organic matter and inorganic matter in sewage sludge are combusted in a bed of particles... combustion of organic matter and inorganic matter in sewage sludge by high temperatures in an enclosed device... accordance with 40 CFR 51.100 (ii). (p) Total hydrocarbons means the organic compounds in the exit gas from a...

Sewage sludge dewatering using flowing liquid metals

DOEpatents

Carlson, L.W.

1985-08-30

This invention relates generally to the dewatering of sludge, and more particularly to the dewatering of a sewage sludge having a moisture content of about 50 to 80% in the form of small cellular micro-organism bodies having internally confined water.

Effects of additives on solidification of API separator sludge.

PubMed

Faschan, A; Tittlebaum, M; Cartledge, F; Eaton, H

1991-08-01

API separator sludge was solidified with various combinations of binders and absorbent soil additives. The binders utilized were Type I Portland Cement, Type C Flyash, and a 1:1 combination of the two. The soil additives used were bentonite, diatomite, Fuller's earth, and two brands of chemically altered bentonites, or organoclays. The effectiveness of the solidification materials was based on their effect on the physical and leaching characteristics of the sludge.It was determined the Portland cement and combination binders provided the sludge with adequate physical and strength characteristics. It was also determined the affinity of each additive for water had an important influence on the physical characteristics of the solidified sludge. The results of the leaching procedure indicated the binders alone reduced the leachability of organic constituents from the sludge by 1/5 to 1/10. It appeared the use of the additives with the binders may have further reduced the leachability of constituents from sludge, with the incorporation of the organoclay additives further reducing leachability by up to 1/2. Also, it appeared the absorbing capacity of the additives was directly related to their ability to reduce the leachability of organic constituents from the sludge.

EMISSIONS OF METALS, CHROMIUM AND NICKEL SPECIES, AND ORGANICS FROM MUNICIPAL WASTEWATER SLUDGE INCINERATORS

EPA Science Inventory

In order to provide data to support regulations on municipal wastewater sludge incineration, emissions of metals, hexavalent chromium, nickel subsulfide, polychlorinated dibenzo-dioxins and furans (PCDD/PCDFs), semivolatile and volatile organic compounds, carbon monoxide (CO)...

Multi-spectral and thermodynamic analysis of the interaction mechanism between Cu2+ and α-amylase and impact on sludge hydrolysis.

PubMed

Zhou, Ruiqi; Liu, Hong; Hou, Guangying; Ju, Lei; Liu, Chunguang

2017-04-01

An increasing amount of heavy metals (e.g., Cu 2+ ) is being discharged into sewage treatment plants and is accumulating in sludge, which is toxic to the enzyme in sludge or soil when the sludge is used as fertilizer, resulting in unfavorable effect on the biological treatment of sludge and the circulation and conversion of materials in soil. In this research, effect of Cu 2+ on sludge hydrolysis by α-amylase is studied from the respect of concentration and components of soluble organic matter in sludge, using three-dimensional fluorescence spectra. Results show that Cu 2+ exposure not only inhibits the hydrolysis of sludge due to the denaturation of α-amylase but also affects the components of soluble organic matter in sludge. In order to illuminate the interaction mechanism between Cu 2+ and α-amylase (a model of hydrolase in sludge), multi-spectra and isothermal titration microcalorimetry techniques are applied. Results show that the secondary structure of α-amylase is changed as that the α-helical content increases and the structure loosens. The microenvironment of amino acid residue in α-amylase is changed that the hydrophobicity decreases and the polarity increases with Cu 2+ exposure. Isothermal titration calorimetry results show that Van der Waals force and hydrogen bond exist in the interaction between Cu 2+ and α-amylase. Results from this research would favor the development of advanced process for the biological treatment of sludge containing heavy metals.

Activated sludge pilot plant: comparison between experimental and predicted concentration profiles using three different modelling approaches.

PubMed

Le Moullec, Y; Potier, O; Gentric, C; Leclerc, J P

2011-05-01

This paper presents an experimental and numerical study of an activated sludge channel pilot plant. Concentration profiles of oxygen, COD, NO(3) and NH(4) have been measured for several operating conditions. These profiles have been compared to the simulated ones with three different modelling approaches, namely a systemic approach, CFD and compartmental modelling. For these three approaches, the kinetics model was the ASM-1 model (Henze et al., 2001). The three approaches allowed a reasonable simulation of all the concentration profiles except for ammonium for which the simulations results were far from the experimental ones. The analysis of the results showed that the role of the kinetics model is of primary importance for the prediction of activated sludge reactors performance. The fact that existing kinetics parameters in the literature have been determined by parametric optimisation using a systemic model limits the reliability of the prediction of local concentrations and of the local design of activated sludge reactors. Copyright © 2011 Elsevier Ltd. All rights reserved.

Aerobic Heterotrophic Bacterial Populations of Sewage and Activated Sludge

PubMed Central

Prakasam, T. B. S.; Dondero, N. C.

1970-01-01

An activated sludge from a sewage treatment plant and a laboratory activated sludge developed on an artificial waste were compared for their ability to utilize 11 aromatic compounds. There were several significant differences between them. The laboratory sludge contained higher numbers of organisms and metabolized the aromatics to a greater extent. Laboratory activated sludges acclimated to utilization of the aromatics differed from each other in population structure and the pattern of oxygen consumption with aromatic substrates. The oxidative patterns of uncontrolled mixed populations were unreliable for investigating metabolic pathways. Extracts of the various sludges elevated the plate counts of the sludges. PMID:5418946

From municipal/industrial wastewater sludge and FOG to fertilizer: A proposal for economic sustainable sludge management.

PubMed

Bratina, Božidar; Šorgo, Andrej; Kramberger, Janez; Ajdnik, Urban; Zemljič, Lidija Fras; Ekart, Janez; Šafarič, Riko

2016-12-01

After a ban on the depositing of untreated sludge in landfills, the sludge from municipal and industrial water-treatment plants can be regarded as a problem. Waste products of the water treatment process can be a problem or an opportunity - a source for obtaining raw materials. In the European Union, raw sludge and fats, oil and grease (FOG) from municipal and industrial wastewater treatment plants (WWTP) cannot be deposited in any natural or controlled environment. For this reason, it must be processed (stabilized, dried) to be used later as a fertilizer, building material, or alternative fuel source suitable for co-incineration in high temperature furnaces (power plants or concrete plants). The processes of drying sludge, where heat and electricity are used, are energy consuming and economically unattractive. Beside energy efficiency, the main problem of sludge drying is in its variability of quality as a raw material. In addition to this, sludge can be contaminated by a number of organic and inorganic pollutants and organisms. Due to the presence or absence of pollutants, different end products can be economically interesting. For example, if the dried sludge contains coliform bacteria, viruses, helminths eggs or smaller quantities of heavy metals, it cannot be used as a fertilizer but can still be used as a fuel. The objectives of the current article is to present a batch-processing pilot device of sludge or digestate that allows the following: (1) low pressure and low temperature energy effective drying of from 10 to 40% remaining water content, (2) disinfection of pathogen (micro)organisms, (3) heavy metal reduction, (4) production of products of predetermined quality (e.g. containing different quantities of water; it can be used as a fertilizer, or if the percentage of water in the dry sludge is decreased to 10%, then the dried sludge can be used as a fuel with a calorific value similar to coal). An important feature is also the utilization of low-pressure technology to prevent odorous gasses from spreading into the environment. There are presented two new technologies: a) Sewage sludge or digestate drying in the vacuum chamber consumes approx. 1 kWh/dm 3 of evaporated water and, therefore, reaches a price of 180-240 Euros/t Dry Matter (DM), and b) Heavy metals' reduction using adsorbing reaction with magnetite nanostructures can decrease the level of heavy metals in the sewage sludge or digestate up to 20% in one cycle, which can be repeated several times on the same sludge. The aim of the paper is to present a newly developed technology which can provide economic and safe use of moderate heavy metals polluted sewage sludge on agricultural lands as organic fertilizer and, therefore, returning the nutrients (nitrogen, phosphorous, potassium) back to the human food chain, instead of being incinerated or landfilled. The proposed drying technology is economically sustainable due to the low vacuum and temperature (35 °C-40 °C), that increases the efficiency of the heat pump (coefficient of performance 5-7,2) of the energy produced by the anaerobic digestion. Hence, the main emphasis is given to the development of: an efficient method for heavy metals' reduction in the sludge treatment chain by using chitosan covered magnetite nanoparticles, an efficient drying method in a vacuum with low temperature energy which can be exploited from sludge digestion to reduce organic matter, and an energy sustainable concept of sludge treatment, with the addition of fats, oil and grease (FOG) to produce enough biogas for sludge drying to produce fertilizer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of mechanical disintegration of activated sludge on the activity of nitrifying and denitrifying bacteria and phosphorus accumulating organisms.

PubMed

Zubrowska-Sudol, Monika; Walczak, Justyna

2014-09-15

The purpose of the study was to analyse the impact of hydrodynamic disintegration of thickened excess activated sludge, performed at different levels of energy density (70, 140 and 210 kJ/L), on the activity of microorganisms involved in nutrient removal from wastewater, i.e. nitrifiers, denitrifiers and phosphorus accumulating organisms (PAOs). Ammonium and nitrogen utilisation rates and phosphorus release rates for raw and disintegrated sludge were determined using batch tests. The experiment also included: 1) analysis of organic and nutrient compound release from activated sludge flocs, 2) determination of the sludge disintegration degree (DD), and 3) evaluation of respiratory activity of the biomass by using the oxygen uptake rate (OUR) batch test. It was shown that the activity degree of the examined groups of microorganisms depended on energy density and related sludge disintegration degree, and that inactivation of individual groups of microorganisms occurred at different values of DD. Least resistant to the destruction of activated sludge flocs turned out to be phosphorus accumulating organisms, while the most resistant were denitrifiers. A decrease of 20-40% in PAO activity was noted already at DD equal to 3-5%. The threshold values of DD, after crossing which the inactivation of nitrifiers and denitrifiers occurred, were equal to 8% and 10%, respectively. At lesser DD values an increase in the activity of these groups of microorganisms was observed, averaging 20.2-41.7% for nitrifiers and 9.98-36.3% for denitrifiers. Copyright © 2014 Elsevier Ltd. All rights reserved.

A decision support tool for selecting the optimal sewage sludge treatment.

PubMed

Turunen, Ville; Sorvari, Jaana; Mikola, Anna

2018-02-01

Sewage sludge contains significant amounts of resources, such as nutrients and organic matter. At the same time, the organic contaminants (OC) found in sewage sludge are of growing concern. Consequently, in many European countries incineration is currently favored over recycling in agriculture. This study presents a Multi-Attribute Value Theory (MAVT)-based decision support tool (DST) for facilitating sludge treatment decisions. Essential decision criteria were recognized and prioritized, i.e., weighted, by experts from water utilities. Since the fate of organic contaminants was in focus, a simple scoring method was developed to take into account their environmental risks. The final DST assigns each sludge treatment method a preference score expressing its superiority compared to alternative methods. The DST was validated by testing it with data from two Finnish municipal wastewater treatment plants (WWTP). The validation results of the first case study preferred sludge pyrolysis (preference score: 0.629) to other alternatives: composting and incineration (score 0.580, and 0.484 respectively). The preference scores were influenced by WWTP dependent factors, i.e., the operating environment and the weighting of the criteria. A lack of data emerged as the main practical limitation. Therefore, not all of the relevant criteria could be included in the value tree. More data are needed on the effects of treatment methods on the availability of nutrients, the quality of organic matter and sludge-borne OCs. Despite these shortcomings, the DST proved useful and adaptable in decision-making. It can also help achieve a more transparent, understandable and comprehensive decision-making process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhancing sewage sludge dewaterability by bioleaching approach with comparison to other physical and chemical conditioning methods.

PubMed

Liu, Fenwu; Zhou, Jun; Wang, Dianzhan; Zhou, Lixiang

2012-01-01

The sewage sludge conditioning process is critical to improve the sludge dewaterability prior to mechanical dewatering. Traditionally, sludge is conditioned by physical or chemical approaches, mostly with the addition of inorganic or organic chemicals. Here we report that bioleaching, an efficient and economical microbial method for the removal of sludge-borne heavy metals, also plays a significant role in enhancing sludge dewaterability. The effects of bioleaching and physical or chemical approaches on sludge dewaterability were compared. The conditioning result of bioleaching by Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans on sludge dewatering was investigated and compared with the effects of hydrothermal (121 degrees C for 2 hr), microwave (1050 W for 50 sec), ultrasonic (250 W for 2 min), and chemical conditioning (24% ferric chloride and 68% calcium oxide; dry basis). The results show that the specific resistance to filtration (SRF) or capillary suction time (CST) of sludge is decreased by 93.1% or 74.1%, respectively, after fresh sludge is conditioned by bioleaching, which is similar to chemical conditioning treatment with ferric chloride and calcium oxide but much more effective than other conditioning approaches including hydrothermal, microwave, and ultrasonic conditioning. Furthermore, after sludge dewatering, bioleached sludge filtrate contains the lowest concentrations of chroma (18 times), COD (542 mg/L), total N (TN, 300 mg/L), NH4(+)-N (208 mg/L), and total P (TP, 2 mg/L) while the hydrothermal process resulted in the highest concentration of chroma (660 times), COD (18,155 mg/L), TN (472 mg/L), NH4(+)-N (381 mg/L), and TP (191 mg/L) among these selected conditioning methods. Moreover, unlike chemical conditioning, sludge bioleaching does not result in a significant reduction of organic matter, TN, and TP in the resulting dewatered sludge cake. Therefore, considering sludge dewaterability and the chemical properties of sludge filtrate and resulting dewatered sludge cakes, bioleaching has potential as an approach for improving sludge dewaterability and reducing the cost of subsequent reutilization or disposal of dewatered sludge.

[Formation Mechanism of Aerobic Granular Sludge and Removal Efficiencies in Integrated ABR-CSTR Reactor].

PubMed

Wu, Kai-cheng; Wu, Peng; Xu, Yue-zhong; Li, Yue-han; Shen, Yao-liang

2015-08-01

Anaerobic Baffled Reactor (ABR) was altered to make an integrated anaerobic-aerobic reactor. The research investigated the mechanism of aerobic sludge granulation, under the condition of continuous-flow. The last two compartments of the ABR were altered into aeration tank and sedimentation tank respectively with seeded sludge of anaerobic granular sludge in anaerobic zone and conventional activated sludge in aerobic zone. The HRT was gradually decreased in sedimentation tank from 2.0 h to 0.75 h and organic loading rate was increased from 1.5 kg x (M3 x d)(-1) to 2.0 kg x (M3 x d)(-1) while the C/N of 2 was controlled in aerobic zone. When the system operated for 110 days, the mature granular sludge in aerobic zone were characterized by compact structure, excellent sedimentation performance (average sedimentation rate was 20.8 m x h(-1)) and slight yellow color. The system performed well in nitrogen and phosphorus removal under the conditions of setting time of 0.75 h and organic loading rate of 2.0 kg (m3 x d)(-1) in aerobic zone, the removal efficiencies of COD, NH4+ -N, TP and TN were 90%, 80%, 65% and 45%, respectively. The results showed that the increasing selection pressure and the high organic loading rate were the main propulsions of the aerobic sludge granulation.

Proof of concept for a new energy-positive wastewater treatment scheme.

PubMed

Remy, C; Boulestreau, M; Lesjean, B

2014-01-01

For improved exploitation of the energy content present in the organic matter of raw sewage, an innovative concept for treatment of municipal wastewater is tested in pilot trials and assessed in energy balance and operational costs. The concept is based on a maximum extraction of organic matter into the sludge via coagulation, flocculation and microsieving (100 μm mesh size) to increase the energy recovery in anaerobic sludge digestion and decrease aeration demand for carbon mineralisation. Pilot trials with real wastewater yield an extraction of 70-80% of total chemical oxygen demand into the sludge while dosing 15-20 mg/L Al and 5-7 mg/L polymer with stable operation of the microsieve and effluent limits below 2-3 mg/L total phosphorus. Anaerobic digestion of the microsieve sludge results in high biogas yields of 600 NL/kg organic dry matter input (oDMin) compared to 430 NL/kg oDMin for mixed sludge from a conventional activated sludge process. The overall energy balance for a 100,000 population equivalent (PE) treatment plant (including biofilter for post-treatment with full nitrification and denitrification with external carbon source) shows that the new concept is an energy-positive treatment process with comparable effluent quality than conventional processes, even when including energy demand for chemicals production. Estimated operating costs for electricity and chemicals are in the same range for conventional activated sludge processes and the new concept.

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

Superfund Innovative Technology Evaluation: Demonstration Bulletin: Organic Extraction Utilizing Solvents

EPA Science Inventory

This technology utilizes liquified gases as the extracting solvent to remove organics, such as hydrocarbons, oil and grease, from wastewater or contaminated sludges and soils. Carbon dioxide is generally used for aqueous solutions, and propane is used for sediment, sludges and ...

Predicting the degradability of waste activated sludge.

PubMed

Jones, Richard; Parker, Wayne; Zhu, Henry; Houweling, Dwight; Murthy, Sudhir

2009-08-01

The objective of this study was to identify methods for estimating anaerobic digestibility of waste activated sludge (WAS). The WAS streams were generated in three sequencing batch reactors (SBRs) treating municipal wastewater. The wastewater and WAS properties were initially determined through simulation of SBR operation with BioWin (EnviroSim Associates Ltd., Flamborough, Ontario, Canada). Samples of WAS from the SBRs were subsequently characterized through respirometry and batch anaerobic digestion. Respirometry was an effective tool for characterizing the active fraction of WAS and could be a suitable technique for determining sludge composition for input to anaerobic models. Anaerobic digestion of the WAS revealed decreasing methane production and lower chemical oxygen demand removals as the SRT of the sludge increased. BioWin was capable of accurately describing the digestion of the WAS samples for typical digester SRTs. For extended digestion times (i.e., greater than 30 days), some degradation of the endogenous decay products was assumed to achieve accurate simulations for all sludge SRTs.

Corrosion of radioactive waste tanks containing washed sludge and precipitates

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

Bickford, D.F.; Congdon, J.W.; Oblath, S.B.

1988-05-01

At the US Department of Energy (DOE) Savannah River Plant, the corrosion of carbon steel storage tanks containing alkaline, high-level radioactive waste is controlled by specification of limits on waste composition and temperature. Laboratory tests, conducted to determine minimum corrosion inhibitor levels, indicated pitting of carbon steel near the waterline for proposed storage conditions. In situ electrochemical measurements of full-scale radioactive process demonstrations were conducted to assess the validity of laboratory tests. The in situ results are compared to those of laboratory tests, with particular regard given to simulated solution composition. Transition metal hydroxide sludge contains strong passivating species formore » carbon steel. Washed precipitate contains organic species that lower solution pH and tend to reduce passivating films, requiring higher inhibitor concentrations than the 0.01 M nitrite required for reactor fuel reprocessing wastes.« less

Effect of metal oxides on the stabilization of soil organic matter

NASA Astrophysics Data System (ADS)

Stelmach, Wioleta

2017-04-01

Soil organic matter (SOM) is protected from decomposition by three mechanisms: 1) biochemical stabilization through the accumulation of recalcitrant SOM compounds, 2) physical stabilization, i.e. spatial inaccessibility of SOM for microbes, and 3) chemical protection of SOM through intimate interaction with minerals and metal oxides. The latter mechanisms suggest that added organic substances (i.e. post-fermentation sludge) can be stabilized by metal oxides to increase C sequestration in soil. The aim of this study was to determine the effects of Fe2O3 - one of the dominant metal oxides in soil - on the sequestration of post-fermentation sludge C in soil by separately tracing the decomposition of sludge and of SOM to carbon dioxide (CO2). To determine changes in SOM turnover after the addition of post-fermentation sludge without/with Fe2O3, the isotopic signatures of both C sources (SOM and post-fermentation sludge) were used. Using differences in the 13C natural abundance of the soil (C3 originated, δ13C = -26) and the post-fermentation sludge (C4 originated, δ13C = -18), the CO2 fluxes arising from both C sources were tracked. Addition of post-fermentation sludge to the soil increased the CO2 production by 30% compared to soil without sludge. δ13C analysis of the total CO2 efflux revealed that post-fermentation sludge decreased SOM decomposition. Fe2O3 slightly suppressed sludge decomposition, and therefore increased C sequestration in soil. Only 30% of the post-fermentation sludge had been mineralized after one month of incubation in the soil. The collective results of my study reveal that application of post-fermentation sludge suppresses SOM decomposition, suggesting its use as a fertilizer could positively influence long-term soil quality. Finally, the success of the 13C natural abundance microcosm labeling approach in my study supports its use as an effective method of analyzing the effects of various fertilization techniques on soil nutrient retention. Such results were only possible by partitioning of the total CO2.

DEVELOPMENT OF RISK ASSESSMENT METHODOLOGY FOR MUNICIPAL SLUDGE INCINERATION

EPA Science Inventory

This is one of a series of reports that present methodologies for assessing the potential risks to humans or other organisms from the disposal or reuse of municipal sludge. he sludge management practices addressed by this series include land application practices, distribution an...

TRACE ORGANICS AND INORGANICS IN DISTRIBUTION AND MARKETING MUNICIPAL SLUDGES

EPA Science Inventory

The land application of municipal wastewater treatment sludges is widely practiced both as an economic treatment method for disposal and to provide an economic soil nutrient amendment for agricultural use. Concerns over the general disposal of sludge to land have focused on sever...

DEVELOPMENT OF RISK ASSESSMENT METHODOLOGY FOR MUNICIPAL SLUDGE LANDFILLING

EPA Science Inventory

This is one of a series of reports that present methodologies for assessing the potential risks to humans or other organisms from the disposal or reuse of municipal sludge. he sludge management practices addressed by this series include land application practices, distribution an...

EFFECTS OF SEWAGE SLUDGE ON DI-(2-ETHYLHEXYL) PHTHALATE UPTAKE BY PLANTS

EPA Science Inventory

Di-(2-ethylhexyl) phthalate (DEHP) is a priority organic pollutant frequently found in municipal sludges. reenhouse study was conducted to determine the effects of sludge on plant uptake of 14 C-DEHP (carbonyl labeled). lants grown included three food chain crops, lettuce (Lactuc...

DEVELOPMENT OF RISK ASSESSMENT METHODOLOGY FOR SURFACE DISPOSAL OF MUNICIPAL SLUDGE

EPA Science Inventory

This is one of a series of reports that present methodologies for assessing the potential risks to humans or other organisms from the disposal or reuse of municipal sludge. he sludge management practices addressed by this series include distribution and marketing programs, landfi...

Greenhouse gas emissions and plant characteristics from soil cultivated with sunflower (Helianthus annuus L.) and amended with organic or inorganic fertilizers.

PubMed

López-Valdez, F; Fernández-Luqueño, F; Luna-Suárez, S; Dendooven, L

2011-12-15

Agricultural application of wastewater sludge has become the most widespread method of disposal, but the environmental effects on soil, air, and crops must be considered. The effect of wastewater sludge or urea on sunflower's (Helianthus annuus L.) growth and yield, the soil properties, and the resulting CO(2) and N(2)O emissions are still unknown. The objectives of this study were to investigate: i) the effect on soil properties of organic or inorganic fertilizer added to agricultural soil cultivated with sunflower, ii) how urea or wastewater sludge increases CO(2) and N(2)O emissions from agricultural soil over short time periods, and iii) the effect on plant characteristics and yield of urea or wastewater sludge added to agricultural soil cultivated with sunflower. The sunflower was fertilized with wastewater sludge or urea or grown in unamended soil under greenhouse conditions while plant and soil characteristics, yield, and greenhouse gas emissions were monitored. Sludge and urea modified some soil characteristics at the onset of the experiment and during the first two months but not thereafter. Some plant characteristics were improved by sludge. Urea and sludge treatments increased the yield at similar rates, while sludge-amended soil significantly increased N(2)O emissions but not CO(2) emissions compared to the other amended or unamended soils. This implies that wastewater sludge increased the biomass and/or the yield; however, from a holistic point of view, using wastewater sludge as fertilizer should be viewed with concern. Copyright © 2011 Elsevier B.V. All rights reserved.

Ultrasonic application to boost hydroxyl radical formation during Fenton oxidation and release organic matter from sludge

PubMed Central

Gong, Changxiu; Jiang, Jianguo; Li, De’an; Tian, Sicong

2015-01-01

We examined the effects of ultrasound and Fenton reagent on ultrasonic coupling Fenton oxidation (U+F) pre-treatment processes for the disintegration of wastewater treatment plant sludge. The results demonstrated that U+F treatment could significantly increase soluble chemical oxygen demand (SCOD), total organic carbon (TOC), and extracellular polymeric substances (EPS) concentrations in sludge supernatant. This method was more effective than ultrasonic (U) or Fenton oxidation (F) treatment alone. U+F treatment increased the release of SCOD by 2.1- and 1.4-fold compared with U and F alone, respectively. U+F treatment increased the release of EPS by 1.2-fold compared with U alone. After U+F treatment, sludge showed a considerably finer particle size and looser microstructure based on fluorescence microscopy, and the concentration of hydroxyl radicals (OH•) increased from 0.26 mM by F treatment to 0.43 mM by U+F treatment based on fluorescence spectrophotometer. This demonstrated that U+F treatment improves the release of organic matter from sludge. PMID:26066562

Comment on "Synergistic co-digestion of solid-organic-waste and municipal-sewage-sludge: 1 plus 1 equals more than 2 in terms of biogas production and solids reduction" [Water Research 87, 416-423].

PubMed

Insam, Heribert; Markt, Rudolf

2016-05-15

Co-digestion of organic waste and sewage sludge enhances biogas production and reduces the mass of remaining solids. This phenomenon of enhanced organic matter decomposition by adding labile substrate is known from other habitats like soils and sediments where it is called priming effect. It is thus suggested to adopt the term priming effect also in environmental biotechnology, and in particular for biomethanisation of wastewater sludges by the addition of energy-rich co-substrates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adsorption/desorption of linear alkylbenzenesulfonate (LAS) and azoproteins by/from activated sludge flocs.

PubMed

Conrad, A; Cadoret, A; Corteel, P; Leroy, P; Block, J-C

2006-01-01

Our study investigated the adsorption/desorption by/from activated sludge flocs, dispersed in river water or in diluted wastewater, of organic compounds (C(11)-LAS, azoalbumin and azocasein) at concentrations relevant to environmental conditions. Activated sludge flocs, used as a model of biological aggregates, are characterized by a very heterogeneous matrix able to sorb the three organic compounds tested at 4 degrees C. The adsorbed amount of C(11)-LAS by activated sludge flocs was higher than that of azocasein or azoalbumin, as shown by the Freundlich parameters (K(ads)=8.6+/-1.7, 1.6+/-0.3 and 0.3+/-0.1 micromol(1-1/n)g(-1)l(1/n) for C(11)-LAS, azocasein and azoalbumin, respectively; n=3 sludges). C(11)-LAS sorption from activated sludge appeared to be partially reversible in river water, while a marked hysteresis phenomenon was observed for azocasein and azoalbumin, implying a low degree of reversibility in their exchange between activated sludge and river water. It has also been displayed that the conductivity variation of bulk water (comprised between 214 and 838 microS cm(-1)) exerted no dramatic effect on the C(11)-LAS desorption from activated sludge flocs, while a little effect of it on azocasein desorption was observed. Thus, biological aggregates as activated sludge flocs can serve as an intermediate carrier for C(11)-LAS, while it represents a sink for proteins.

Sewage sludge solubilization by high-pressure homogenization.

PubMed

Zhang, Yuxuan; Zhang, Panyue; Guo, Jianbin; Ma, Weifang; Fang, Wei; Ma, Boqiang; Xu, Xiangzhe

2013-01-01

The behavior of sludge solubilization using high-pressure homogenization (HPH) treatment was examined by investigating the sludge solid reduction and organics solubilization. The sludge volatile suspended solids (VSS) decreased from 10.58 to 6.67 g/L for the sludge sample with a total solids content (TS) of 1.49% after HPH treatment at a homogenization pressure of 80 MPa with four homogenization cycles; total suspended solids (TSS) correspondingly decreased from 14.26 to 9.91 g/L. About 86.15% of the TSS reduction was attributed to the VSS reduction. The increase of homogenization pressure from 20 to 80 MPa or homogenization cycle number from 1 to 4 was favorable to the sludge organics solubilization, and the protein and polysaccharide solubilization linearly increased with the soluble chemical oxygen demand (SCOD) solubilization. More proteins were solubilized than polysaccharides. The linear relationship between SCOD solubilization and VSS reduction had no significant change under different homogenization pressures, homogenization cycles and sludge solid contents. The SCOD of 1.65 g/L was solubilized for the VSS reduction of 1.00 g/L for the three experimental sludge samples with a TS of 1.00, 1.49 and 2.48% under all HPH operating conditions. The energy efficiency results showed that the HPH treatment at a homogenization pressure of 30 MPa with a single homogenization cycle for the sludge sample with a TS of 2.48% was the most energy efficient.

Model calibration and validation for OFMSW and sewage sludge co-digestion reactors

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

Esposito, G., E-mail: giovanni.esposito@unicas.it; Frunzo, L., E-mail: luigi.frunzo@unina.it; Panico, A., E-mail: anpanico@unina.it

2011-12-15

Highlights: > Disintegration is the limiting step of the anaerobic co-digestion process. > Disintegration kinetic constant does not depend on the waste particle size. > Disintegration kinetic constant depends only on the waste nature and composition. > The model calibration can be performed on organic waste of any particle size. - Abstract: A mathematical model has recently been proposed by the authors to simulate the biochemical processes that prevail in a co-digestion reactor fed with sewage sludge and the organic fraction of municipal solid waste. This model is based on the Anaerobic Digestion Model no. 1 of the International Watermore » Association, which has been extended to include the co-digestion processes, using surface-based kinetics to model the organic waste disintegration and conversion to carbohydrates, proteins and lipids. When organic waste solids are present in the reactor influent, the disintegration process is the rate-limiting step of the overall co-digestion process. The main advantage of the proposed modeling approach is that the kinetic constant of such a process does not depend on the waste particle size distribution (PSD) and rather depends only on the nature and composition of the waste particles. The model calibration aimed to assess the kinetic constant of the disintegration process can therefore be conducted using organic waste samples of any PSD, and the resulting value will be suitable for all the organic wastes of the same nature as the investigated samples, independently of their PSD. This assumption was proven in this study by biomethane potential experiments that were conducted on organic waste samples with different particle sizes. The results of these experiments were used to calibrate and validate the mathematical model, resulting in a good agreement between the simulated and observed data for any investigated particle size of the solid waste. This study confirms the strength of the proposed model and calibration procedure, which can thus be used to assess the treatment efficiency and predict the methane production of full-scale digesters.« less

Dynamic modeling of nitrogen removal for a three-stage integrated fixed-film activated sludge process treating municipal wastewater.

PubMed

Moretti, Paul; Choubert, Jean-Marc; Canler, Jean-Pierre; Buffière, Pierre; Pétrimaux, Olivier; Lessard, Paul

2018-02-01

The integrated fixed-film activated sludge (IFAS) process is being increasingly used to enhance nitrogen removal for former activated sludge systems. The aim of this work is to evaluate a numerical model of a new nitrifying/denitrifying IFAS configuration. It consists of two carrier-free reactors (anoxic and aerobic) and one IFAS reactor with a filling ratio of 43% of carriers, followed by a clarifier. Simulations were carried out with GPS-X involving the nitrification reaction combined with a 1D heterogeneous biofilm model, including attachment/detachment processes. An original iterative calibration protocol was created comprising four steps and nine actions. Experimental campaigns were carried out to collect data on the pilot in operation, specifically for modelling purpose. The model used was able to predict properly the variations of the activated sludge (bulk) and the biofilm masses, the nitrification rates of both the activated sludge and the biofilm, and the nitrogen concentration in the effluent for short (4-10 days) and long (300 days) simulation runs. A calibrated parameter set is proposed (biokinetics, detachment, diffusion) related to the activated sludge, the biofilm and the effluent variables to enhance the model prediction on hourly and daily data sets.

CHARACTERIZATION OF ACTINIDES IN SIMULATED ALKALINE TANK WASTE SLUDGES AND LEACHATES

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

Nash, Kenneth L.

In this project, both the fundamental chemistry of actinides in alkaline solutions (relevant to those present in Hanford-style waste storage tanks), and their dissolution from sludge simulants (and interactions with supernatants) have been investigated under representative sludge leaching procedures. The leaching protocols were designed to go beyond conventional alkaline sludge leaching limits, including the application of acidic leachants, oxidants and complexing agents. The simulant leaching studies confirm in most cases the basic premise that actinides will remain in the sludge during leaching with 2-3 M NaOH caustic leach solutions. However, they also confirm significant chances for increased mobility of actinidesmore » under oxidative leaching conditions. Thermodynamic data generated improves the general level of experiemental information available to predict actinide speciation in leach solutions. Additional information indicates that improved Al removal can be achieved with even dilute acid leaching and that acidic Al(NO3)3 solutions can be decontaminated of co-mobilized actinides using conventional separations methods. Both complexing agents and acidic leaching solutions have significant potential to improve the effectiveness of conventional alkaline leaching protocols. The prime objective of this program was to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop.« less

Carbon source recovery from excess sludge by mechanical disintegration for biological denitrification.

PubMed

Zubrowska-Sudol, M

2018-04-01

The goal of the study was to evaluate the possibility of carbon source recovery from excess sludge by mechanical disintegration for biological denitrification. The total efficiency of denitrification, unit demand for organic compounds for denitrification, unit volume of disintegrated sludge and unit cost of nitrogen removal as a function of energy density used for excess sludge disintegration (70, 140 and 210 kJ/L) were analyzed. In the study a full-scale disc disintegrator was used (motor power: 30 kWh, motor speed: 2,950 rpm). It was shown that the amounts of organic compounds released from the activated sludge flocs at all tested levels of energy density are high enough to be used to intensify the removal of nitrogen compounds from wastewater. It was also documented that the energy density provided during process of disintegration was an important factor determining the characteristics of organic compounds obtained under the disintegration for their use in order to intensify the process of denitrification. The highest value of total efficiency of denitrification (50.5 ± 3.1 mg N/L) was obtained for carbon source recovery from excess sludge at 70 kJ/L, but the lowest unit cost of nitrogen removal occurred for 140 kJ/L (0.0019 ± 0.0011 EUR/g N).

Predicting the apparent viscosity and yield stress of mixtures of primary, secondary and anaerobically digested sewage sludge: Simulating anaerobic digesters.

PubMed

Markis, Flora; Baudez, Jean-Christophe; Parthasarathy, Rajarathinam; Slatter, Paul; Eshtiaghi, Nicky

2016-09-01

Predicting the flow behaviour, most notably, the apparent viscosity and yield stress of sludge mixtures inside the anaerobic digester is essential because it helps optimize the mixing system in digesters. This paper investigates the rheology of sludge mixtures as a function of digested sludge volume fraction. Sludge mixtures exhibited non-Newtonian, shear thinning, yield stress behaviour. The apparent viscosity and yield stress of sludge mixtures prepared at the same total solids concentration was influenced by the interactions within the digested sludge and increased with the volume fraction of digested sludge - highlighted using shear compliance and shear modulus of sludge mixtures. However, when a thickened primary - secondary sludge mixture was mixed with dilute digested sludge, the apparent viscosity and yield stress decreased with increasing the volume fraction of digested sludge. This was caused by the dilution effect leading to a reduction in the hydrodynamic and non-hydrodynamic interactions when dilute digested sludge was added. Correlations were developed to predict the apparent viscosity and yield stress of the mixtures as a function of the digested sludge volume fraction and total solids concentration of the mixtures. The parameters of correlations can be estimated using pH of sludge. The shear and complex modulus were also modelled and they followed an exponential relationship with increasing digested sludge volume fraction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Stabilization of heavy metals in municipal sewage sludge by freeze-thaw treatment with a blend of diatomite, FeSO4, and Ca(OH)2.

PubMed

Wang, Jing; Fu, Rongbing; Xu, Zhen

2017-08-01

In this work, the effects of diatomite with 15% FeSO 4 •7H 2 O and 7.5% Ca(OH) 2 on sludge stabilization were investigated using batch leaching tests. The influence of cell rupture caused by freezing and thawing on stabilization was also evaluated. The results indicated that the optimal diatomite percentage was 2%. Cell rupture by freezing and thawing reduced heavy metal leachability, followed by cell death and decrease of organic groups. The concentration of heavy metals in sludge leachate increased after cell rupture, indicating that the heavy metal leachability was reduced after freezing and thawings. Moreover, the stabilization effects were generally improved after freezing and thawing. As compared with the stabilization of the original sludge, the unstable fractions decreased and the residual fractions of the heavy metals increased in the stabilized sludge after cell rupture. This study developed a method to stabilize heavy metals in municipal sewage sludge. Diatomite combined with FeSO 4 ·7H 2 O and Ca(OH) 2 improved the treatment of sewage sludge contaminated by heavy metals. Cell lysis by freeze-thaw treatment reduced the risk of leaching heavy metals caused by cell death and decreased major organic groups in the sludge.

Electron beam inactivation of selected microbial pathogens and indicator organisms in aerobically and anaerobically digested sewage sludge.

PubMed

Praveen, Chandni; Jesudhasan, Palmy R; Reimers, Robert S; Pillai, Suresh D

2013-09-01

Microbial pathogens in municipal sewage sludges need to be inactivated prior to environmental disposal. The efficacy of high energy (10 MeV) e-beam irradiation to inactivate a variety of selected microbial pathogens and indicator organisms in aerobically and anaerobically digested sewage sludge was evaluated. Both bacterial and viral pathogens and indicator organisms are susceptible to e-beam irradiation. However, as expected there was a significant difference in their respective e-beam irradiation sensitivity. Somatic coliphages, bacterial endospores and enteric viruses were more resistant compared to bacterial pathogens. The current US EPA mandated 10 kGy minimum dose was capable of achieving significant reduction of both bacterial and viral pathogens. Somatic coliphages can be used as a microbial indicator for monitoring e-beam processes in terms of pathogen inactivation in sewage sludges. Copyright © 2013 Elsevier Ltd. All rights reserved.

Total organic carbon in a soil recovered with sewage sludge and native species of the Atlantic Forest

NASA Astrophysics Data System (ADS)

Mara Lima Goulart, Lívia; Amaral Guerrini, Iraê; Fidalgo de Faria, Marianne; Spada, Grasiela; Proença Nalesso, Pedro Henrique; Willian Carlos, Guilherme

2017-04-01

The use of organic waste such as sewage sludge, in the recovery of degraded áreas have shown very satisfactory results, because they are constituted by high contentes of organic matter and nutrients, essential to improve the physical and chemical properties of the soil. Thus, the objective of this study was to verify the total organic carbon (TOC) of a degraded soil, up to a metre deep, after 10 years of application of sewage sludge and planting native species of the Atlantic forest. The experiment was conducted at Fazenda Entre-Rios, owned by Suzano Papel e Celulose, in Itatinga, São Paulo, Brazil. The experiment was designed as randomized block with four replications, six doses of sewage sludge (0, 2.5, 5, 10, 15 and 20 t ha-1), conventional chemical fertilizer and only with potassium application, totaling eight treatments. Samples were collected every 20 cm (0-20, 20-40, 40-60, 60-80 and 80-100 cm) until reaching a metre deep. Ten years after trial deployment, the sewage sludge application in degraded soil was significantly influenced the TOC at all depths sampled. The highest values of the COT were observed in plots that received 15 and 20 t ha-1 of sewage sludge, in all depths sampled, except for the layer of 80-100 cm, which presented the highest average COT in the treatment with 10 t ha-1 of residue. As observed for all treatments, the highest TOC averages were observed in the superficial layers of the soil (0-20 and 20-40 cm). The sewage sludge application is useful to recover degraded soils, as it improving their chemical characteristics and showing to be a good alternative to the final destination of this residue.

Assessment of mobility and bioavailability of mercury compounds in sewage sludge and composts.

PubMed

Janowska, Beata; Szymański, Kazimierz; Sidełko, Robert; Siebielska, Izabela; Walendzik, Bartosz

2017-07-01

Content of heavy metals, including mercury, determines the method of management and disposal of sewage sludge. Excessive concentration of mercury in composts used as organic fertilizer may lead to accumulation of this element in soil and plant material. Fractionation of mercury in sewage sludge and composts provides a better understanding of the extent of mobility and bioavailability of the different mercury species and helps in more informed decision making on the application of sludge for agricultural purposes. The experimental setup comprises the composing process of the sewage sludge containing 13.1mgkg -1 of the total mercury, performed in static reactors with forced aeration. In order to evaluate the bioavailability of mercury, its fractionation was performed in sewage sludge and composts during the process. An analytical procedure based on four-stage sequential extraction was applied to determine the mercury content in the ion exchange (water soluble and exchangeable Hg), base soluble (Hg bound to humic and fulvic acid), acid soluble (Hg bound to Fe/Mn oxides and carbonates) and oxidizable (Hg bound to organic matter and sulphide) fractions. The results showed that from 50.09% to 64.55% of the total mercury was strongly bound to organo-sulphur and inorganic sulphide; that during composting, increase of concentrations of mercury compounds strongly bound with organic matter and sulphides; and that mercury content in the base soluble and oxidizable fractions was strongly correlated with concentration of dissolved organic carbon in those fractions. Copyright © 2017 Elsevier Inc. All rights reserved.

Development of Risk Assessment Methodology for Land Application and Distribution and Marketing of Municipal Sludge

EPA Science Inventory

This is one of a series of reports that present methodologies for assessing the potential risks to humans or other organisms from the disposal or reuse of municipal sludge. The sludge management practices addressed by this series include land application practices, distribution a...

DEMONSTRATION BULLETIN: THE BASIC EXTRACTIVE SLUDGE TREATMENT (B.E.S.T.) RESOURCES CONSERVATION COMPANY (RCC)

EPA Science Inventory

The Basic Extractive Sludge Treatment (B.E.S.T.®) process is a solvent extraction system that separates organic contaminants from sludges, soils, and sediments. The primary distinguishing feature of the process is the extraction agent, triethylamine. The key to the success of tri...

SUPERFUND TREATABILITY CLEARINGHOUSE: INPUT/OUTPUT DATA FOR SEVERAL TREATMENT TECHNOLOGIES

EPA Science Inventory

This treatability study is a pilot-scale evaluation of a thin-film evaporator (TFE) for volatile organics (VO) removal from oily sludges such as refinery sludges. TFEs were studied to evaluate their use to remove and recover VO from these sludges prior to land treatment. This w...

Transformation of heavy metal speciation during sludge drying: mechanistic insights

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

Weng, Huanxin; Ma, Xue-Wen; Fu, Feng-Xia

2014-01-30

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized the Cr, Cu, Cd and Pb in sludge by transforming acid-soluble, reducible andmore » oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge.« less

New technology for recyclingmaterials from oily cold rollingmill sludge

NASA Astrophysics Data System (ADS)

Liu, Bo; Zhang, Shen-gen; Tian, Jian-jun; Pan, De-an; Meng, Ling; Liu, Yang

2013-12-01

Oily cold rolling mill (CRM) sludge is one of metallurgical industry solid wastes. The recycle of these wastes can not only protect the environment but also permit their reutilization. In this research, a new process of "hydrometallurgical treatment + hydrothermal synthesis" was investigated for the combined recovery of iron and organic materials from oily CRM sludge. Hydrometallurgical treatment, mainly including acid leaching, centrifugal separation, neutralization reaction, oxidizing, and preparation of hydrothermal reaction precursor, was first utilized for processing the sludge. Then, micaceous iron oxide (MIO) pigment powders were prepared through hydrothermal reaction of the obtained precursor in alkaline media. The separated organic materials can be used for fuel or chemical feedstock. The quality of the prepared MIO pigments is in accordance with the standards of MIO pigments for paints (ISO 10601-2007). This clean, effective, and economical technology offers a new way to recycle oily CRM sludge.

Influence of sludge retention time on tolerance of copper toxicity for polyphosphate accumulating organisms linked to polyhydroxyalkanoates metabolism and phosphate removal.

PubMed

Tsai, Yung-Pin; Chen, Hsiu-Ting

2011-12-01

This study explored the influence of sludge retention time (SRT) on tolerance of copper invasion for polyphosphate accumulating organisms (PAOs) in an enhanced biological phosphorus removal (EBPR). The experimental data showed the anaerobic polyhydroxyalkanoates (PHA) storage for the sludge at 10d SRT was less influenced by copper invasion than those at 5d and 15d SRTs. The reaction of PAOs aerobically taking up phosphate for the sludge at 5d or 15d SRT almost ceased at 2 mg Cu L(-1), whereas PAOs in the sludge at 10d SRT retained half of the ability to take up phosphate. Both the PHAs degradation and synthesis rates decreased with increasing copper concentration, regardless of the SRTs. However, the copper inhibition of the former was greater than that of the later. Copyright © 2011 Elsevier Ltd. All rights reserved.

Sludge incineration tests on circulating fluidised bed furnace.

PubMed

Lotito, V; Mininni, G; Di Pinto, A C; Spinosa, L

2001-01-01

Results of sludge incineration tests on a demonstrative fluidised bed furnace are reported and discussed. They show that particulate, heavy metals and acidic compounds in the emissions can be easily controlled both when sludge is spiked with chlorinated hydrocarbons up to a chlorine concentration in the feed of 5%, and when the afterburner is switched off. As for organic micropollutants, polynuclear aromatic hydrocarbons (PAH) were much lower than the Italian limits of 10 microg/m3 (no limits are at present considered in the European Directives). Dioxins (PCDDs) and furans (PCDFs) in some tests exceeded the limit of 0.1 ng/m3 (TE) but the concentrations in the fly ashes were much lower, thus evidencing a possible presence of contaminants in gas phase. PAHs and PCDD/PCDFs were not depending on the afterburning operation, the presence of organic chlorine in the feed sludge and the copper addition to sewage sludge.

Phytoextraction of Zn and Cu from sewage sludge and impact on agronomic characteristics.

PubMed

Xiaomei, Liu; Qitang, Wu; Banks, M K; Ebbs, S D

2005-01-01

The presence of elevated concentrations of heavy metals limits the usage of sewage sludge as a fertilizer and soil amendment. Experiments were carried out to examine the extent to which seven plant species phytoextracted Zn and Cu from dewatered sludge. The hyperaccumulators Thlaspi caerulescens and Sedum alfredii showed the greatest removal of Zn, while shoots and tubers of two species of Alocasia showed the greatest Cu removal. Cultivation of plants in the sludge resulted in significant decreases in total Zn and changes in the partitioning of Zn between soil pools. However, Cu levels were largely unchanged and remained associated predominantly with the organic matter pool. Agronomic characteristics of the sludge material, such as pH, organic matter content, and nitrogen, phosphorus, and potassium concentrations, did not change significantly during the four-month growth period, indicating that subsequent crops could be sustained by this material. These results suggest that Zn can be phytoextracted from sludge material, provided the rate of metal uptake exceeds the rate of mobilization to the exchangeable fraction. Since there was no appreciable accumulation of Zn and Cu in seeds of Zea mays in this study, some tissues from sludge-grown plants could potentially be used as animal fodder.

Sludge reduction and microbial community structure in an anaerobic/anoxic/oxic process coupled with potassium ferrate disintegration.

PubMed

An, Ying; Zhou, Zhen; Yao, Jie; Niu, Tianhao; Qiu, Zhan; Ruan, Danian; Wei, Haijuan

2017-12-01

An anaerobic/anoxic/oxic (AAO) wastewater treatment system combining with a potassium ferrate (K 2 FeO 4 ) oxidation side-stream reactor (SSR) was proposed for sludge reduction. Batch experiments showed that optimal K 2 FeO 4 dosage and reaction time for sludge disintegration was 100mg/g suspended solids (SS) and 24h, respectively. Subsequently, an AAO-SSR and a conventional AAO were operated in parallel to investigate effects of K 2 FeO 4 oxidation on process performance, sludge characteristics and microbial community structures. The AAO-SSR process operated under the optimized condition achieved efficient COD and NH 4 + -N removal, and reduced sludge by 47.5% with observed yield coefficient of 0.21gSS/g COD. K 2 FeO 4 addition broke sludge particles, increased dissolved organic matters in the mixed liquor, and improved sludge dewaterability. Illumina-MiSeq sequencing results showed that K 2 FeO 4 oxidation in the AAO-SSR decreased microbial richness and diversity, enriched slow growers (Dechloromonas), anaerobic fermentative bacteria (Azospira) and Fe(III)-reducing bacteria (Ferribacterium), but limited the growth of phosphate-accumulating organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Monitoring the fate and behavior of TiO2 nanoparticles: Simulated in a WWTP with industrial dye-stuff effluent according to OECD 303A.

PubMed

Mahlalela, Lwazi C; Ngila, Jane C; Dlamini, Langelihle N

2017-07-03

The use of nanoparticles (NPs) in several consumer products has led to them finding their way into wastewater treatment plants (WWTPs). Some of these NPs have photocatalytic properties, thus providing a possible solution to textile industries to photodegrade dyes from their wastewater. Thus, the interaction of NPs with industrial dye effluents is inevitable. The Organization for Economic Co-operation and development (OECD) guideline for testing of chemical 303A was employed to study the fate and behaviour of TiO 2 NPs in industrial dye-stuff effluent. This was due to the unavailability of NPs' fate and behaviour test protocols. The effect of TiO 2 NPs on the treatment process was ascertained by measuring chemical oxygen demand (COD) and 5-day biological oxygen demand (BOD5). Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to study the fate and behavior of TiO 2 NPs. Acclimatization of bacteria to target pollutants was a crucial factor for the treatment efficiency of activated sludge in a simulated wastewater treatment plant (SWTP). The acclimatization of the activated sludge to the synthetic industrial dye-stuff effluent was successfully achieved. Effect of TiO 2 NPs on the treatment process efficiency was then investigated. Addition of TiO 2 NPs had no effect on the treatment process as chemical oxygen demand (COD) removal remained >80%. Measured total plate count (TPC) affirmed that the addition of TiO 2 NPs had no effect on the treatment process. The removal of total nitrogen (TN) was not efficient as the treatment system was required to have an oxic and anoxic stage for efficient TN removal. Results from X-ray powder diffraction (XRD) confirmed that the anatase phase of the added TiO 2 NPs remained unchanged even after exposure to the treatment plant. Removal of the NPs from the influent was facilitated by biosorption of the NPs on the activated sludge. Nanoparticles received by wastewater treatment plants will therefore reach the environment through sludge waste dumped in landfill. About 90% of TiO 2 was retained in the activated sludge, and 10-11% escaped with the treated effluents. Scanning electron microscope (SEM) mapping micrographs together with an energy dispersive X-ray spectroscopy (EDS) confirmed the presence of Ti in the sludge.

Simulation and optimization of a coking wastewater biological treatment process by activated sludge models (ASM).

PubMed

Wu, Xiaohui; Yang, Yang; Wu, Gaoming; Mao, Juan; Zhou, Tao

2016-01-01

Applications of activated sludge models (ASM) in simulating industrial biological wastewater treatment plants (WWTPs) are still difficult due to refractory and complex components in influents as well as diversity in activated sludges. In this study, an ASM3 modeling study was conducted to simulate and optimize a practical coking wastewater treatment plant (CWTP). First, respirometric characterizations of the coking wastewater and CWTP biomasses were conducted to determine the specific kinetic and stoichiometric model parameters for the consecutive aeration-anoxic-aeration (O-A/O) biological process. All ASM3 parameters have been further estimated and calibrated, through cross validation by the model dynamic simulation procedure. Consequently, an ASM3 model was successfully established to accurately simulate the CWTP performances in removing COD and NH4-N. An optimized CWTP operation condition could be proposed reducing the operation cost from 6.2 to 5.5 €/m(3) wastewater. This study is expected to provide a useful reference for mathematic simulations of practical industrial WWTPs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sulfidation treatment of copper-containing plating sludge towards copper resource recovery.

PubMed

Kuchar, D; Fukuta, T; Onyango, M S; Matsuda, H

2006-11-02

The present study is concerned with the sulfidation treatment of copper-containing plating sludge towards copper resource recovery by flotation of copper sulfide from treated sludge. The sulfidation treatment was carried out by contacting simulated or real copper plating sludge with Na(2)S solution for a period of 5 min to 24 h. The initial molar ratio of S(2-) to Cu(2+) (S(2-) to Me(2+) in the case of real sludge) was adjusted to 1.00, 1.25 or 1.50, while the solid to liquid ratio was set at 1:50. As a result, it was found that copper compounds were converted to various copper sulfides within the first 5 min. In the case of simulated copper sludge, CuS was identified as the main sulfidation product at the molar ratio of S(2-) to Cu(2+) of 1.00, while Cu(7)S(4) (Roxbyite) was mainly found at the molar ratios of S(2-) to Cu(2+) of 1.50 and 1.25. Based on the measurements of oxidation-reduction potential, the formation of either CuS or Cu(7)S(4) at different S(2-) to Cu(2+) molar ratios was attributed to the changes in the oxidation-reduction potential. By contrast, in the case of sulfidation treatment of real copper sludge, CuS was predominantly formed, irrespective of S(2-) to Me(2+) molar ratio.

First-order hydrothermal oxidation kinetics of digested sludge compared with raw sludge.

PubMed

Shanableh, A; Imteaz, M

2008-09-01

This article presents an assessment of the first-order hydrothermal oxidation kinetics of a selected digested sludge at subcritical (< 374 degrees C) and supercritical (> 374 degrees C) temperatures in the range of 250-460 degrees C. Furthermore, the results were compared with reported oxidation kinetics of raw sludge treated under identical experimental conditions. In the assessment, oxidation was considered to proceed in two steps: (1) decomposition of the particulate, or non-filterable, chemical oxygen demand (PCOD); followed by (2) ultimate oxidation and removal of the total, particulate and soluble, COD. The accumulation and removal of soluble COD (SCOD) was determined from the difference between the rates of sludge decomposition and ultimate oxidation. Using results from batch and continuous-flow hydrothermal treatment experiments, the reacting organic ingredients were separated into groups according to the ease or difficulty at which they were decomposed or removed, with Arrhenius-type activation energy levels assigned to the different groups. The analysis confirmed that within the treatment range of 75% to more than 97% COD removal, the oxidation kinetics of the digested and raw sludges were nearly identical despite differences in the proportions of their original organic ingredients. The original organic ingredients were mostly removed above 75% COD removal, and the oxidation kinetics appeared to be dominated by the removal of acetic acid, an intermediate by-product which constituted 50% to more than 80% of the remaining COD. Furthermore, the oxidation kinetics of both sludge types were consistent with reported first-order oxidation kinetics of pure acetic acid solutions. The resulting kinetic models adequately represented hydrothermal oxidation of digested sludge, in terms of COD and PCOD removals, as well as accumulation and removal of the soluble SCOD.

Single application of Sewage Sludge to an Alluvial Agricultural Soil - impacts on Soil Quality

NASA Astrophysics Data System (ADS)

Suhadolc, M.; Graham, D. B.; Hagn, A.; Doerfler, U.; Schloter, M.; Schroll, R.; Munch, J. C.; Lobnik, F.

2009-04-01

Limited information exists on the effects of sewage sludge on soil quality with regard to their ability to maintain soil functions. We studied effects of sewage sludge amendment on soil chemical properties, microbial community structure and microbial degradation of the herbicide glyphosate. Three months soil column leaching experiment has been conducted using alluvial soils (Eutric Fluvisol) with no prior history of sludge application. The soil was loamy with pH 7,4 and organic matter content of 3,5%. Soil material in the upper 2 cm of columns was mixed with dehydrated sewage sludge which was applied in amounts corresponding to the standards governing the use of sewage sludge for agricultural land. Sludge did increase some nutrients (total N, NH4+, available P and K, organic carbon) and some heavy metals contents (Zn, Cu, Pb) in soil. However, upper limits for heavy metals in agricultural soils were not exceeded. Results of heavy metal availability in soil determined by sequential extraction will be also presented. Restriction fragment length polymorphism (RFLP) analyses of 16s/18s rDNA, using universal fungal and bacterial primers, revealed clear shifts in bacterial and fungal community structure in the upper 2 cm of soils after amendment. Fungal fingerprints showed greater short term effects of sewage sludge, whereas sewage sludge seems to have prolonged effects on soil bacteria. Furthermore, sewage sludge amendment significantly increased glyphosate degradation from 21.6±1% to 33.6±1% over a 2 months period. The most probable reasons for shifts in microbial community structure and increased degradation of glyphosate are beneficial alterations to the physical-chemical characteristics of the soil. Negative effects of potentially toxic substances present in the sewage sludge on soil microbial community functioning were not observed with the methods used in our study.

Application of biochar to sewage sludge reduces toxicity and improve organisms growth in sewage sludge-amended soil in long term field experiment.

PubMed

Kończak, Magdalena; Oleszczuk, Patryk

2018-06-01

The aim of the present study was to determine changes in the physicochemical properties and toxicity of soil amended with sewage sludge (10t dw /ha) or sewage sludge (10t dw /ha) with biochar addition (2.5, 5 or 10% of sewage sludge). The study was carried out as a field experiment over a period of 18months. Samples for analysis were taken at the beginning of the experiment as well as after 6, 12 and 18months. The study investigated toxicity of the unamended soil, sewage sludge-amended soil and sewage sludge-amended soil with biochar addition towards Folsomia candida (collembolan test) and Lepidium sativum (Phytotoxkit F). Moreover, toxicity of aqueous extracts obtained from the tested soils towards Vibrio fischeri (Microtox®) and Lepidium sativum (elongation test) was determined. The study showed that addition of biochar to the sewage sludge and soil reduced leaching of nutrients (mainly phosphorus and potassium) from the amended soil. Biochar significantly reduced sewage sludge toxicity, exhibiting a stimulating effect on the tested organisms. The stimulating effect of biochar addition to the sewage sludge persisted throughout the entire experiment. Apart from the remediatory character of biochar, this is also evidence of its fertilizing character. In the tests with L. sativum (leachates and solid phase) and V. fischeri (leachates), increasing the rate of biochar in the sewage sludge increased root growth stimulation (L. sativum) and bacteria luminescence (V. fischeri). However, increasing biochar rate decreased F. candida reproduction stimulation, which could have been an effect of reduced nutrient bioavailability due to the biochar. Copyright © 2017 Elsevier B.V. All rights reserved.

The investigation of solid slag obtained by neutralization of sewage sludge.

PubMed

Kavaliauskas, Zydrunas; Valincius, Vitas; Stravinskas, Giedrius; Milieska, Mindaugas; Striugas, Nerijus

2015-11-01

The purpose of this research is to investigate the feasibility of utilizing the slag collected after gasification of organic fuel combined with sewage sludge. The residue left after gasification process is likely usable as raw material for production of supercondensers. The sewage sludge neutralization system consists of a dosing system (fuel tank), gasifier, plasma reactor, electrostatic filter, and heat exchangers. For the gasification process, dried solid sewage is supplied in proportion of 70% to biomass 30% by weight. The slag is collected in a specially designed chamber beneath the gasifier. A scanning electron microscope (SEM) was used to evaluate surface morphology of the samples. Elemental analysis of the sewage sludge slag was performed using the energy-dispersive spectroscopy (EDS) method, which showed different solid-state elements contained in the porous structure of the solid phase: carbon 29%, aluminum 26%, potassium 20%, chlorine 1%, and others. The specific surface area of the sewage sludge slag is 6.15 m(2)/g as the BET analysis shows. In order to use the slag as a secondary raw material, detailed analysis of the structure and properties is necessary for a decision on whether the slag left after gasification of sewage sludge is suitable for any further usages. Initial results indicate that the slag may be used for production of electrodes for supercapacitors. Every year thousands of tons of sewage sludge are formed in Lithuania. Sewage sludge consists of organic and inorganic compounds. Partial combustion, plasma decomposition, and other methods are used to neutralize the sewage sludge. The incineration of sewage sludge results in generation of solid-phase slag. In this paper the material structure and composition of a solid slag (formed during neutralization of sewage sludge) is considered. Also, the impact the ambient temperature on structure and composition of solid slag is analyzed.

Bioassay directed identification of toxicants in sludge and related reused materials from industrial wastewater treatment plants in the Yangtze River Delta.

PubMed

Fang, Binbin; Guo, Jing; Li, Fuxing; Giesy, John P; Wang, Lianjun; Shi, Wei

2017-02-01

Industrialized development of the Yangtze River Delta, China, has resulted in larger amounts of wastes, including sludges from treatment of these wastes. Methods to manage and dispose, including reuse were urgently needed. Sludge and reused products were collected from two largest factories, KEYUAN and HENGJIA where treated sludges were turned into bricks or sludge cake to be placed in landfills, respectively. Metals and organic compounds were quantified in sludges and leachates assessed by use of toxicity characterized leaching procedure (TCLP) while acute toxicity was determined by Daphnia magna. Nine metals were detected in all raw sludges with concentrations of Cr and Ni exceeding Chinese standards. For sludge leachate, concentrations of metals were all less than Chinese standards, which changed little after being made into cake by HENGJIA, but were significantly less after being made into brick by KEYUAN. Toxicity units (TU) for all samples are greater than 1.0 indicating that they are potentially toxic to aquatic organisms. TUs changed little after being made into filter cake, but were 10-fold less after being made into bricks. Cr and Ni contributed most to the total toxicity followed by Zn and Cu. Making of sludges into K-brick 1 resulted in better inactivation of contaminants, which resulted in less toxic potencies. So that is the recommended method for handling of industrial sludges. To further assure their safe reuse, additional research on identification of key toxicants and potential hazards, based on additional endpoints, by combining bio-tests and chemical analysis should be done for reused sludges. Copyright © 2016 Elsevier Ltd. All rights reserved.

Plant available nitrogen from anaerobically digested sludge and septic tank sludge applied to crops grown in the tropics.

PubMed

Sripanomtanakorn, S; Polprasert, C

2002-04-01

Agricultural land is an attractive alternative for the disposal of biosolids since it utilises the recyclable nutrients in the production of crops. In Thailand and other tropical regions, limited field-study information exists on the effect of biosolids management strategies on crop N utilisation and plant available N (PAN) of biosolids. A field study was conducted to quantify the PAN of the applied biosolids, and to evaluate the N uptake rates of some tropical crops. Sunflower (Helianthus annuus) and tomato (Lycopersicon esculentum) were chosen in this study. Two types of biosolids used were: anaerobically digested sludge and septic tank sludge. The soil is acid sulfate and is classified as Sulfic Tropaquepts with heavy clay in texture. The anaerobically digested sludge applied rates were: 0, 156 and 312 kg N ha(-1) for the sunflower plots, and 0, 586, and 1172 kg N ha(-1) for the tomato plots. The septic tank sludge applied rates were: 0, 95 and 190 kg N ha(-1) for the sunflower plots, and 0, 354 and 708 kg N ha(-1) for the tomato plots, respectively. The results indicated the feasibility of applying biosolids to grow tropical crops. The applications of the anaerobically digested sludge and the septic tank sludge resulted in the yields of sunflower seeds and tomato fruits and the plant N uptakes comparable or better than that applied with only the chemical fertiliser. The estimated PAN of the anaerobically digested sludge was about 27-42% of the sludge organic N during the growing season. For the septic tank sludge, the PAN was about 15-58% of the sludge organic N. It is interesting to observe that an increase of the rate of septic tank sludge incorporated into this heavy clay soil under the cropping system resulted in the decrease of N mineralisation rate. This situation could cause the reduction of yield and N uptake of crops.

Analysis of Pharmaceutical and Personal Care Compounds in Wastewater Sludge and Aqueous Samples using GC-MS/MS

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

Zhong, Lirong; Mitroshkov, Alexandre V.; Gilmore, Tyler J.

The Bioenergy Program at Pacific Northwest National Laboratory (PNNL) is evaluating the feasibility of converting wastewater sludge materials to fuels. Wastewater sludge from various municipalities will be used in the evaluation process and as with any municipal waste, there is the potential for residual contaminates to remain in the sludge following wastewater treatment. Many surveys and studies have confirmed the presence of pharmaceuticals in municipal wastewater and effluents (World Health Organization, 2011). Determination of the presence and concentrations of the contaminants is required to define the proper handling of this sludge. A list of targeted compounds was acquired from themore » literature and an analytical method was developed for the pharmaceutical and personal care compounds. The presence of organics complicated the analytical techniques and, in some cases, the precision of the results. However, residual concentrations of a range of compounds were detected in the wastewater sludge and the presence and concentrations of these compounds will be considered in identifying the appropriate handling of this material in conduct of research.« less

Deep dewatering process of sludge by chemical conditioning and its potential influence on wastewater treatment plants.

PubMed

Wang, Shuo; Ma, Cong; Zhu, Yin; Yang, Yangkun; Du, Guocheng; Li, Ji

2018-06-15

FeCl 3 , quick lime, and cationic polyacrylamide (CPAM) were used for excess sludge conditioning from wastewater treatment plant (WWTP) and the dewatering performance by different chemical conditioners was investigated. Experimental results showed that FeCl 3 could make small and concentrated sludge particles. Furthermore, new mineral phase structures for building a dewatering framework were obtained by the addition of quick lime, and the coagulation capacity was enhanced by the formation of colloid hydroxyl polymer, which was induced due to the alkaline environment. In addition, the floc particle size significantly increased after the CPAM dosage. The bound water could be released with the stripping of tightly bound extracellular polymeric substance (EPS). Therefore, the dewatering performance and efficiencies were improved and subsequently the hypothetical sludge deep dewatering process was depicted in accordance with the variation of EPS. However, high-strength refractory organics in sludge filtrates caused by quick lime pyrolysis could lead to the unstable operation of the WWTP, because the relatively high concentrations of organic compounds with benzene were dominant in sludge dewatering filtrates.

Toxicity to Eisenia andrei and Folsomia candida of a metal mixture applied to soil directly or via an organic matrix.

PubMed

Natal-da-Luz, T; Ojeda, G; Pratas, J; Van Gestel, C A M; Sousa, J P

2011-09-01

Regulatory limits for chemicals and ecological risk assessment are usually based on the effects of single compounds, not taking into account mixture effects. The ecotoxicity of metal-contaminated sludge may, however, not only be due to its metal content. Both the sludge matrix and the presence of other toxicants may mitigate or promote metal toxicity. To test this assumption, the toxicity of soils recently amended with an industrial sludge predominantly contaminated with chromium, copper, nickel, and zinc and soils freshly spiked with the same mixture of metals was evaluated through earthworm (Eisenia andrei) and collembolan (Folsomia candida) reproduction tests. The sludge was less toxic than the spiked metal mixture for E. andrei but more toxic for F. candida. Results obtained for the earthworms suggest a decrease in metal bioavailability promoted by the high organic matter content of the sludge. The higher toxicity of the sludge for F. candida was probably due to the additive toxic effect of other pollutants. Copyright © 2011 Elsevier Inc. All rights reserved.

Environmental risk evaluation of the use of mine spoils and treated sewage sludge in the ecological restoration of limestone quarries

NASA Astrophysics Data System (ADS)

Jordán, M. M.; Pina, S.; García-Orenes, F.; Almendro-Candel, M. B.; García-Sánchez, E.

2008-07-01

The ecologic restoration criteria in areas degraded from extraction activities require making use of their mine spoils. These materials do not meet fertility conditions to guarantee restoration success and therefore, need the incorporation of organic amendments to obtain efficient substratum. Reducing the deficiencies in the organic material and restoration material nutrients with the contribution of treated sewage sludge is proposed in this work. This experiment was based on a controlled study using columns. The work was conducted with two mine spoils, both very rich in calcium carbonate. The first mineral, of poor quality, came from the formation of aggregates of crushed limestone ( Z). The other residual material examined originated in limestone extraction, formed by the levels of interspersed non-limestone materials and the remains of stripped soils ( D). Two treatments were undertaken (30,000 and 90,000 kg/ha of sewage sludge), in addition to a control treatment. The water contribution was carried out with a device that simulated either short-duration rain or a flooding irrigation system in order to cover the surface and then percolate through the soil. The collection of leached water took place 24 h after the applications. Different parameters of the leached water were determined, including pH, electrical conductivity, nitrate anions, ammonium, phosphates, sulphates and chlorides. The values obtained for each irrigation application are discussed, and the nitrate values obtained were very elevated.

Nitrogen removal from the saline sludge liquor by electrochemical denitrification.

PubMed

Xie, Z M; Li, X Y; Chan, K Y

2006-01-01

Sludge liquor from the sludge dewatering process has a high ammonia content. In the present study, a lab-scale electrochemical (EC) system with a pair of Ti electrode plates was used for treating the sludge centrate liquor of digested wastewater sludge with a NH4(+) - N content of around 500 mg/L. The sludge liquor had a high salinity due to seawater being used for toilet flushing in Hong Kong. The results show that the EC process is highly effective for denitrification of the saline sludge liquor. Complete nitrogen removal could be achieved within 1 hr or so. The rate of EC denitrification increased with the current intensity applied. The best current efficiency for nitrogen removal was obtained for a gap distance between the electrodes at 8 mm. Electro-chlorination was considered to be the major mechanism of EC denitrification. The formation of chlorination by-products (CBPs) appeared to be minimal with the total trihalomethanes (THM) detected at a level of 300 microg/L or lower. The power consumption for EC denitrification was around 23 kWh/kg N. Additional electro-flocculation with a pair of iron needle electrodes could enhance the flocculation and subsequent sedimentation of colloidal organics in the sludge liquor, increasing the organic removal from less than 30% to more than 70%. Therefore, the EC process including both electro-denitrification and electro-flocculation can be developed as the most cost-effective method for treatment of the saline sludge liquor.

Enhanced treatment efficiency of an anaerobic sequencing batch reactor (ASBR) for cassava stillage with high solids content.

PubMed

Luo, Gang; Xie, Li; Zhou, Qi

2009-06-01

Cassava stillage is a high strength organic wastewater with high suspended solids (SS) content. The efficiency of cassava stillage treatment using an anaerobic sequencing batch reactor (ASBR) was significantly enhanced by discharging settled sludge to maintain a lower sludge concentration (about 30 g/L) in the reactor. Three hydraulic retention times (HRTs), namely 10 d, 7.5 d, 5 d, were evaluated at this condition. The study demonstrated that at an HRT of 5 d and an organic loading rate (OLR) of 11.3 kg COD/(m(3) d), the total chemical oxygen demand (TCOD) and soluble COD (SCOD) removal efficiency can still be maintained at above 80%. The settleability of digested cassava stillage was improved significantly, and thus only a small amount of settled sludge needed to be discharged to maintain the sludge concentration in the reactor. Furthermore, the performance of ASBR operated at low and high sludge concentration (about 79.5 g/L without sludge discharged) was evaluated at an HRT of 5 d. The TCOD removal efficiency and SS in the effluent were 61% and 21.9 g/L respectively at high sludge concentration, while the values were 85.1% and 2.4 g/L at low sludge concentration. Therefore, low sludge concentration is recommended for ASBR treating cassava stillage at an HRT 5 d due to lower TCOD and SS in the effluent, which could facilitate post-treatment.

Laboratory measurements of radiance and reflectance spectra of dilute primary-treated sewage sludge

NASA Technical Reports Server (NTRS)

Usry, J. W.; Witte, W. G.; Whitlock, C. H.; Gurganus, E. A.

1977-01-01

The feasibility of remotely monitoring ocean dumping of waste products such as acid and sewage sludge is evaluated. The laboratory arrangement, solar simulator, and test results from three experiments conducted in the laboratory are described. Radiance and reflectance spectra are presented for primary-treated sewage sludge mixed with two types of base water. Results indicate that upwelled reflectance varies in a near-linear manner with concentration and that the sludge has a practically flat signal response between 420 and 970 nm. Well-defined upwelled reflectance spectra were obtained for the sewage-sludge mixtures at all wavelengths and concentrations. The spectral-reflectance values appeared to be influenced by the type of base water, but this influence was small, especially for the mixtures with low concentrations of sewage sludge.

Multi-scale individual-based model of microbial and bioconversion dynamics in aerobic granular sludge.

PubMed

Xavier, Joao B; De Kreuk, Merle K; Picioreanu, Cristian; Van Loosdrecht, Mark C M

2007-09-15

Aerobic granular sludge is a novel compact biological wastewater treatment technology for integrated removal of COD (chemical oxygen demand), nitrogen, and phosphate charges. We present here a multiscale model of aerobic granular sludge sequencing batch reactors (GSBR) describing the complex dynamics of populations and nutrient removal. The macro scale describes bulk concentrations and effluent composition in six solutes (oxygen, acetate, ammonium, nitrite, nitrate, and phosphate). A finer scale, the scale of one granule (1.1 mm of diameter), describes the two-dimensional spatial arrangement of four bacterial groups--heterotrophs, ammonium oxidizers, nitrite oxidizers, and phosphate accumulating organisms (PAO)--using individual based modeling (IbM) with species-specific kinetic models. The model for PAO includes three internal storage compounds: polyhydroxyalkanoates (PHA), poly phosphate, and glycogen. Simulations of long-term reactor operation show how the microbial population and activity depends on the operating conditions. Short-term dynamics of solute bulk concentrations are also generated with results comparable to experimental data from lab scale reactors. Our results suggest that N-removal in GSBR occurs mostly via alternating nitrification/denitrification rather than simultaneous nitrification/denitrification, supporting an alternative strategy to improve N-removal in this promising wastewater treatment process.

A review on sludge dewatering indices.

PubMed

To, Vu Hien Phuong; Nguyen, Tien Vinh; Vigneswaran, Saravanamuth; Ngo, Huu Hao

2016-01-01

Dewatering of sludge from sewage treatment plants is proving to be a significant challenge due to the large amounts of residual sludges generated annually. In recent years, research and development have focused on improving the dewatering process in order to reduce subsequent costs of sludge management and transport. To achieve this goal, it is necessary to establish reliable indices that reflect the efficiency of sludge dewatering. However, the evaluation of sludge dewaterability is not an easy task due to the highly complex nature of sewage sludge and variations in solid-liquid separation methods. Most traditional dewatering indices fail to predict the maximum cake solids content achievable during full-scale dewatering. This paper reviews the difficulties in assessing sludge dewatering performance, and the main techniques used to evaluate dewatering performance are compared and discussed in detail. Finally, the paper suggests a new dewatering index, namely the modified centrifugal index, which is demonstrated to be an appropriate indicator for estimating the final cake solids content as well as simulating the prototype dewatering process.

Characteristics of oily sludge combustion in circulating fluidized beds.

PubMed

Zhou, Lingsheng; Jiang, Xiumin; Liu, Jianguo

2009-10-15

Incineration of oily sludge in circulating fluidized beds may be an effective way for its management in some cases. The objective of the present paper is to investigate combustion characteristics of oily sludge, which would be helpful and useful for the design and simulation of a circulating fluidized bed. Firstly, the pyrolysis and combustion of oily sludge were studied through some thermal analyses, which included the thermogravimetric (TG) analysis and the differential thermal analytical (DTA) analysis. It was found that the combustion of oily sludge might be the combustion of its pyrolysis products. Secondly, an experiment for measuring of main components of the volatile from oily sludge pyrolysis was carried out. Some mathematic correlations about the compositions of volatile from oily sludge devolatilization were achieved from the experimental results. Finally, the combustion characteristics of oily sludge was studied in a lab-scale circulating fluidized bed, which could obtain some information about the location of release and combustion of the volatiles.

Development of an ATP measurement method suitable for xenobiotic treatment activated sludge biomass.

PubMed

Nguyen, Lan Huong; Chong, Nyuk-Min

2015-09-01

Activated sludge consumes a large amount of energy to degrade a xenobiotic organic compound. By tracking the energy inventory of activated sludge biomass during the sludge's degradation of a xenobiotic, any disadvantageous effect on the sludge's performance caused by energy deficiency can be observed. The purpose of this study was to develop a reliable and accurate method for measuring the ATP contents of activated sludge cells that were to degrade a xenobiotic organic. Cell disruption and cellular ATP extraction were performed by a protocol with which xenobiotic degrading activated sludge biomass was washed with SDS, treated by Tris and TCA, and followed by bead blasting. The suspension of disrupted cells was filtered before the filtrate was injected into HPLC that was set at optimal conditions to measure the ATP concentration therein. This extraction protocol and HPLC measurement of ATP was evaluated for its linearity, limits of detection, and reproducibility. Evaluation test results reported a R(2) of 0.999 of linear fit of ATP concentration versus activated sludge concentration, a LOD=0.00045mg/L, a LOQ=0.0015mg/L for HPLC measurement of ATP, a MDL=0.46mg/g SS for ATP extraction protocol, and a recovery efficiency of 96.4±2%. This method of ATP measurement was simple, rapid, reliable, and was unburdened of some limitations other methods may have. Copyright © 2015 Elsevier B.V. All rights reserved.

Sequencing batch reactor biofilm system for treatment of milk industry wastewater.

PubMed

Sirianuntapiboon, Suntud; Jeeyachok, Narumon; Larplai, Rarintorn

2005-07-01

A sequencing batch reactor biofilm (MSBR) system was modified from the conventional sequencing batch reactor (SBR) system by installing 2.7 m2 surface area of plastic media on the bottom of the reactor to increase the system efficiency and bio-sludge quality by increasing the bio-sludge in the system. The COD, BOD5, total kjeldahl nitrogen (TKN) and oil & grease removal efficiencies of the MSBR system, under a high organic loading of 1340 g BOD5/m3 d, were 89.3+/-0.1, 83.0+/-0.2, 59.4+/-0.8, and 82.4+/-0.4%, respectively, while they were only 87.0+/-0.2, 79.9+/-0.3, 48.7+/-1.7 and 79.3+/-10%, respectively, in the conventional SBR system. The amount of excess bio-sludge in the MSBR system was about 3 times lower than that in the conventional SBR system. The sludge volume index (SVI) of the MSBR system was lower than 100 ml/g under an organic loading of up to 1340 g BOD5/m3 d. However, the MSBR under an organic loading of 680 g BOD5/m3 d gave the highest COD, BOD5, TKN and oil & grease removal efficiencies of 97.9+/-0.0, 97.9+/-0.1, 79.3+/-1.0 and 94.8+/-0.5%, respectively, without any excess bio-sludge waste. The SVI of suspended bio-sludge in the MSBR system was only 44+/-3.4 ml/g under an organic loading of 680 g BOD5/m3 d.

Valorization of a pharmaceutical organic sludge through different composting treatments.

PubMed

Cucina, Mirko; Tacconi, Chiara; Sordi, Simone; Pezzolla, Daniela; Gigliotti, Giovanni; Zadra, Claudia

2018-04-01

Nowadays, the agricultural reuse of pharmaceutical sludge is still limited due to environmental and agronomic issues (e.g. low stabilization of the organic matter, phytotoxicity). The aim of the present study was to evaluate the characteristics of a pharmaceutical sludge derived from the daptomycin production and to study the possibility of improving its quality through composting. The pharmaceutical sludge showed high content of macronutrients (e.g. total Kjeldahl N content was 38 g kg -1 ), but it was also characterized by high salinity (7.9 dS m -1 ), phytotoxicity (germination index was 36.7%) and a low organic matter stabilization. Two different mixtures were prepared (mixture A: 70% sludge + 30% wood chips w/w, mixture B: 45% sludge + 45% wood chips + 10% cereal straw w/w) and treated through static composting using two different aeration systems: active and passive aeration. The mixtures resulted in the production of two different compost, and the evolution of process management parameters was different. The low total solids and organic matter content of mixture A led to the failure of the process. The addition of cereal straw in mixture B resulted in increased porosity and C/N ratio and, consequently, in an optimal development of the composting process (e.g. the final organic matter loss was 54.1% and 63.1% for the passively and actively aerated treatment, respectively). Both passively and actively aerated composting of mixture B improved the quality of the pharmaceutical sludge, by increasing its organic matter stabilization and removing phytotoxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sludge-grown algae for culturing aquatic organisms: Part I. Algal growth in sludge extracts

NASA Astrophysics Data System (ADS)

Hung, K. M.; Chiu, S. T.; Wong, M. H.

1996-05-01

This project is aimed at studying the feasibility of using sewage sludge to prepare culture media for microalgae ( Chlorella-HKBU) and the use of the sludge-grown algae as a feed for some aquatic organisms. Part I of the project included results on preparing sludge extracts and their use on algal culture. By comparing two culturing techniques, “aeration” and “shaking,” it was noted that both lag and log phases were shortened in the aeration system. A subsequent experiment noted that algal growth subject to aeration rates of 1.0 and 1.5 liters/min had similar lag and log phases. In addition, both aeration rates had a significantly higher ( P < 0.05) final cell density than that of 0.5 liters/min. A detailed study on the variation of growth conditions on the algal growth was done. The results indicated that pH values of all the cultures declined below 5 at day 12. The removal rates of ammonia N ranged from 62% to 70%. The sludge-grown algae contained a rather substantial amount of heavy metals (µg/g): Zn 289 581, Cu 443 682, Ni 310 963, Mn 96 126, Cr 25 118, and Fe 438 653. This implied that the rather high levels of heavy metals may impose adverse effects on higher trophic organisms.

Influence of organic and inorganic flocculants on the formation of PCDD/Fs during sewage sludge incineration.

PubMed

Lin, Xiaoqing; Li, Xiaodong; Lu, Shengyong; Wang, Fei; Chen, Tong; Yan, Jianhua

2015-10-01

Flocculants are widely used to improve the properties of sludge dewatering in industrial wastewater treatment. However, there have been no studies conducted on the influence of flocculants on the formation of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) during sewage sludge incineration. This paper selected three typical kinds of flocculants, including polyacrylamide (PAM), poly-ferric chloride (PFC), and polyaluminum chloride (PAC) flocculant, to study their influences on the formation of PCDD/Fs during sewage sludge incineration. The results indicated that PAM flocculant, which is an organic flocculant, inhibited the formation of PCDD/Fs in sewage sludge incineration, while inorganic flocculant, such as PFC and PAC flocculant, promoted the formation. The most probable explanation is that the amino content in the PAM flocculant acted as an inhibitor in the formation of PCDD/Fs, while the chlorine content, especially the metal catalyst in the PFC and PAC flocculants, increased the formation rate. The addition of flocculants nearly did not change the distribution of PCDD/F homologues. The PCDFs contributed the most toxic equivalent (TEQ) value, especially 2, 3, 4, 7, 8-PeCDF. Therefore, the use of inorganic flocculants in industrial wastewater treatment should be further assessed and possibly needs to be strictly regulated if the sludge is incinerated. From this aspect, a priority to the use of organic flocculants should be given.

High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation.

PubMed

Ekstrand, Eva-Maria; Karlsson, Marielle; Truong, Xu-Bin; Björn, Annika; Karlsson, Anna; Svensson, Bo H; Ejlertsson, Jörgen

2016-10-01

Kraft fibre sludge from the pulp and paper industry constitutes a new, widely available substrate for the biogas production industry, with high methane potential. In this study, anaerobic digestion of kraft fibre sludge was examined by applying continuously stirred tank reactors (CSTR) with sludge recirculation. Two lab-scale reactors (4L) were run for 800days, one on fibre sludge (R1), and the other on fibre sludge and activated sludge (R2). Additions of Mg, K and S stabilized reactor performance. Furthermore, the Ca:Mg ratio was important, and a stable process was achieved at a ratio below 16:1. Foaming was abated by short but frequent mixing. Co-digestion of fibre sludge and activated sludge resulted in more robust conditions, and high-rate operation at stable conditions was achieved at an organic loading rate of 4g volatile solids (VS)L(-1)day(-1), a hydraulic retention time of 4days and a methane production of 230±10NmL per g VS. Copyright © 2016. Published by Elsevier Ltd.

Transformation of heavy metal speciation during sludge drying: mechanistic insights.

PubMed

Weng, Huan-Xin; Ma, Xue-Wen; Fu, Feng-Xia; Zhang, Jin-Jun; Liu, Zan; Tian, Li-Xun; Liu, Chongxuan

2014-01-30

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized Cr, Cu, Cd, and Pb in sludge by transforming acid-soluble, reducible, and oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge. Copyright © 2013 Elsevier B.V. All rights reserved.

Benchmark simulation model no 2: general protocol and exploratory case studies.

PubMed

Jeppsson, U; Pons, M-N; Nopens, I; Alex, J; Copp, J B; Gernaey, K V; Rosen, C; Steyer, J-P; Vanrolleghem, P A

2007-01-01

Over a decade ago, the concept of objectively evaluating the performance of control strategies by simulating them using a standard model implementation was introduced for activated sludge wastewater treatment plants. The resulting Benchmark Simulation Model No 1 (BSM1) has been the basis for a significant new development that is reported on here: Rather than only evaluating control strategies at the level of the activated sludge unit (bioreactors and secondary clarifier) the new BSM2 now allows the evaluation of control strategies at the level of the whole plant, including primary clarifier and sludge treatment with anaerobic sludge digestion. In this contribution, the decisions that have been made over the past three years regarding the models used within the BSM2 are presented and argued, with particular emphasis on the ADM1 description of the digester, the interfaces between activated sludge and digester models, the included temperature dependencies and the reject water storage. BSM2-implementations are now available in a wide range of simulation platforms and a ring test has verified their proper implementation, consistent with the BSM2 definition. This guarantees that users can focus on the control strategy evaluation rather than on modelling issues. Finally, for illustration, twelve simple operational strategies have been implemented in BSM2 and their performance evaluated. Results show that it is an interesting control engineering challenge to further improve the performance of the BSM2 plant (which is the whole idea behind benchmarking) and that integrated control (i.e. acting at different places in the whole plant) is certainly worthwhile to achieve overall improvement.

The effects of salinity and temperature on phase transformation of copper-laden sludge.

PubMed

Hsieh, Ching-Hong; Shih, Kaimin; Hu, Ching-Yao; Lo, Shang-Lien; Li, Nien-Hsun; Cheng, Yi-Ting

2013-01-15

To stabilize the copper and aluminum ions in simulated sludge, a series of sintering processes were conducted to transform Cu/Al precipitation into spinel structure, CuAl(2)O(4). The results indicated that the large amount of salt content in the simulated sludge would hinder the formation of crystalline CuAl(2)O(4) generated from the incorporation of CuO and Al(2)O(3), even after the sintering process at 1200 °C. Opposite to the amorphous CuAl(2)O(4), the crystalline CuAl(2)O(4) can be formed in the sintering process at 700-1100 °C for 3 h with the desalinating procedure. According to the theory of free energy, the experimental data and references, the best formation temperature of CuAl(2)O(4) was determined at 900-1000 °C. As the temperature rose to 1200 °C, CuAlO(2) was formed with the dissociation of CuAl(2)O(4). The XPS analysis also showed that the binding energy of copper species in the simulated sludge was switched from 933.8 eV for Cu(II) to 932.8 eV for Cu(I) with the variation of temperature. In this system, the leaching concentration of copper and aluminum ions from sintered simulated sludge was decreased with ascending temperature and reached the lowest level at 1000 °C. Furthermore, the descending tendency coincided with the formation tendency of spinel structure and the diminishing of copper oxide. Copyright © 2012 Elsevier B.V. All rights reserved.

Electrochemical probing of high-level radioactive waste tanks containing washed sludge and precipitates

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

Bickford, D.F.; Congdon, J.W.; Oblath, S.B.

1986-12-01

At the US Department of Energy's Savannah River Plant, corrosion of carbon steel storage tanks containing alkaline, high-level radioactive waste is controlled by specification of limits on waste composition and temperature. Processes for the preparation of waste for final disposal will result in waste with low corrosion inhibitor concentrations and, in some cases, high aromatic organic concentrations, neither of which are characteristic of previous operations. Laboratory tests, conducted to determine minimum corrosion inhibitor levels indicated pitting of carbon steel near the waterline for proposed storage conditions. In situ electrochemical measurements of full-scale radioactive process demonstrations have been conducted to assessmore » the validity of laboratory tests. Probes included pH, Eh (potential relative to a standard hydrogen electrode), tank potential, and alloy coupons. In situ results are compared to those of the laboratory tests, with particular regard given to simulated solution composition. Transition metal hydroxide sludge contains strong passivating species for carbon steel. Washed precipitate contains organic species that lower solution pH and tend to reduce passivating films, requiring higher inhibitor concentrations than the 0.01 molar nitrite required for reactor fuel reprocessing wastes. Periodic agitation, to keep the organic phase suspended, or cathodic protection are possible alternatives to higher nitrite inhibitor concentrations.« less

Phosphorus in waters from sewage sludge amended lysimeters.

PubMed

Hinesly, T D; Jones, R L

1990-01-01

In surface waters, phosphorus (P) concentrations exceeding 0.05 mg liter(-1) may cause eutrophic conditions. This study was undertaken to measure total P concentrations in runoff and tile drainage waters from land receiving either inorganic fertilizer or anaerobically digested sewage sludge. Total P was measured in runoff and tile drainage waters during 2 years of sample collections from instrumented, large-scale lysimeters planted to corn (Zea mays L.). During the 3 years prior to monitoring P concentrations, six of the lysimeter plots had been amended with anaerobically digested sewage sludge which supplied 5033 kg P per ha. Additional sludge applications supplied 1058 and 1989 kg P per ha during the first and second years of monitoring operations, respectively. Another six lysimeters were annually treated with fertilizer which included P applications amounting to 112 kg ha(-1). For years 1 and 2, respectively, annual losses from lysimeters treated with sewage sludge were 4.27 and 0.35 kg P per ha in runoff and 0.91 from 0.91 and 0.51 kg Per P per ha in drainage waters. Parallel annual losses of P from lysimeters treated with superphosphate were 2.15 and 0.17 kg ha(-1) in runoff and 0.53 and 0.35 kg ha(-1) in tile drainage waters. Sludge applications did not significantly change absolute soil contents of organic P, but did decrease the per cent of total P present in organic forms. Sludge and soil, respectively, contained 21 and 36% of their total P contents in organic forms. In sludge and soil about 85 and 64% of their respective total inorganic P contents were associated with the Al and Fe fractions. Sludge applications significantly increased soil contents of P in the saloid (water-soluble plus P extracted with 1 N NH(4)Cl), Al, Fe and reductant soluble P fractions, but contents of Ca-bound P were not changed. Total P contents of the soil below a depth of 30 cm were not affected by sludge incorporated to a depth of about 15 cm by plowing.

Organics removal, nitrogen removal and N2O emission in subsurface wastewater infiltration systems amended with/without biochar and sludge.

PubMed

Sun, Yafei; Qi, Shiyue; Zheng, Fanping; Huang, Linli; Pan, Jing; Jiang, Yingying; Hou, Wanyuan; Xiao, Lu

2018-02-01

Organics removal, nitrogen removal, N 2 O emission and nitrogen removal functional gene abundances in four subsurface wastewater infiltration systems (SWISs), named SWIS A (no intermittent aeration without biochar and sludge), SWIS B (no intermittent aeration with biochar and sludge), SWIS C (intermittent aeration without biochar and sludge), SWIS D (intermittent aeration with biochar and sludge) were investigated. Intermittent aeration enhanced chemical oxygen demand (COD), ammonia nitrogen (NH 4 + -N), total nitrogen (TN) removal and the abundances of nitrogen removal functional genes (amoA, nxrA, napA, narG, nirS, nirK, qnorB and nosZ) compared to non-aerated SWISs. High COD (95.4 ± 0.2%), NH 4 + -N (96.2 ± 0.6%), TN (86.4 ± 0.5%) removal efficiencies and low N 2 O emission rate (18.4 mg/(m 2  d)) were obtained simultaneously in intermittent aerated SWIS amended with biochar and sludge. The results suggested that intermittent aerated SWISs amended with biochar and sludge could be an effective and appropriate method for improving treatment performance and reducing N 2 O emission. Copyright © 2017 Elsevier Ltd. All rights reserved.

Visible light photocatalytic disintegration of waste activated sludge for enhancing biogas production.

PubMed

Anjum, Muzammil; Al-Talhi, Hasan A; Mohamed, Saleh A; Kumar, Rajeev; Barakat, M A

2018-06-15

Biogas production using waste activated sludge (WAS) is one of the most demanding technologies for sludge treatment and generating energy in sustainable manner. The present study deals with the photocatalytic pretreatment of WAS using ZnO-ZnS@polyaniline (ZnO-ZnS@PANI) nanocomposite as means for increasing its degradability for improved biogas production by anaerobic digestion (AD). Photocatalysis accelerated the hydrolysis of WAS and increased the sCOD by 6.7 folds after 6 h and transform tCOD into bioavailable sCOD. After the AD of WAS, a removal of organic matter (60.6%) and tCOD (69.3%) was achieved in photocatalytic pretreated sludge. The biogas production was 1.6 folds higher in photocatalytic sludge with accumulative biogas up to 1645.1 ml L -1 vs after 45 days compared with the raw sludge (1022.4 ml L -1 VS ). Moreover, the photocatalysis decrease the onset of methanogenesis from 25 to 12 days while achieve the maximum conversion rate of reducing sugars into organic acids at that time. These results suggested that photocatalysis is an efficient pretreatment method and ZnO-ZnS@PANI can degrade sludge efficiently for enhance biogas production in anaerobic digestion process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chlorella vulgaris cultivation in sludge extracts from 2,4,6-TCP wastewater treatment for toxicity removal and utilization.

PubMed

Wang, Lu; Chen, Xiurong; Wang, Hualin; Zhang, Yuying; Tang, Qingjie; Li, Jiahui

2017-02-01

Chlorella vulgaris was cultivated in different proportions of activated sludge extracts, which was from the treatment of the synthetic wastewater containing 2,4,6-trichlorophenol (2,4,6-TCP). The nutrients, total nitrogen (TN) and total phosphorus (TP), were removed over 45% and 90%, respectively. The maximum reduction amount of ecotoxicity and total organic carbon (TOC) occurred in the 100% sludge group on the 8th day (68%; 86.2 mg L -1 ). The variations of Excitation-emission matrix spectra (EEMs) and TOC indicated that extracellular organic matters (EOM) produced by algae led to TOC increase in the medium. The cell density was close to each other for groups with sludge extract proportion below 50%; sludge extracts (below 75% addition) had a stimulating effect on the accumulation of chlorophyll-a in per unit algal cell. Superoxide dismutase (SOD) variation demonstrated that C. vulgaris response positively to sludge extracts addition. Lipid content in C. vulgaris was up to its maximum value on the 8th day. Considering the performance on nutrients removal, toxicity reduction and algal growth, the optimal cultivation period for C. vulgaris before harvesting was around 8 days with sludge extracts proportion below 50%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simulation of co-incineration of sewage sludge with municipal solid waste in a grate furnace incinerator.

PubMed

Lin, Hai; Ma, Xiaoqian

2012-03-01

Incineration is one of the most important methods in the resource recovery disposal of sewage sludge. The combustion characteristics of sewage sludge and an increasing number of municipal solid waste (MSW) incineration plants provide the possibility of co-incineration of sludge with MSW. Computational fluid dynamics (CFD) analysis was used to verify the feasibility of co-incineration of sludge with MSW, and predict the effect of co-incineration. In this study, wet sludge and semi-dried sludge were separately blended with MSW as mixed fuels, which were at a co-incineration ratios of 5 wt.% (wet basis, the same below), 10 wt.%, 15 wt.%, 20 wt.% and 25 wt.%. The result indicates that co-incineration of 10 wt.% wet sludge with MSW can ensure the furnace temperature, the residence time and other vital items in allowable level, while 20 wt.% of semi-dried sludge can reach the same standards. With lower moisture content and higher low heating value (LHV), semi-dried sludge can be more appropriate in co-incineration with MSW in a grate furnace incinerator. Copyright © 2011 Elsevier Ltd. All rights reserved.

Peracetic acid oxidation as an alternative pre-treatment for the anaerobic digestion of waste activated sludge.

PubMed

Appels, Lise; Van Assche, Ado; Willems, Kris; Degrève, Jan; Van Impe, Jan; Dewil, Raf

2011-03-01

Anaerobic digestion is generally considered to be an economic and environmentally friendly technology for treating waste activated sludge, but has some limitations, such as the time it takes for the sludge to be digested and also the ineffectiveness of degrading the solids. Various pre-treatment technologies have been suggested to overcome these limitations and to improve the biogas production rate by enhancing the hydrolysis of organic matter. This paper studies the use of peracetic acid for disintegrating sludge as a pre-treatment of anaerobic digestion. It has been proved that this treatment effectively leads to a solubilisation of organic material. A maximum increase in biogas production by 21% is achieved. High dosages of PAA lead to a decrease in biogas production. This is due to the inhibition of the anaerobic micro-organisms by the high VFA-concentrations. The evolution of the various VFAs during digestion is studied and the observed trends support this hypothesis. Copyright © 2010 Elsevier Ltd. All rights reserved.

The effect of mixing ratio variation of sludge and organic solid waste on biodrying process

NASA Astrophysics Data System (ADS)

Nasution, A. C.; Kristanto, G. A.

2018-01-01

In this study, organic waste was co-biodried with sludge cake to determine which mixing ratio gave the best result. The organic waste was consisted of dried leaves and green leaves, while the sludge cake was obtained from a waste water treatment plant in Bekasi. The experiment was performed on 3 lab-scale reactors with same specifications. After 21 days of experiment, it was found that the reactor with the lowest mixing fraction of sludge (5:1) has the best temperature profile and highest moisture content depletion compared with others. Initial moisture content and initial volatile solid content of this reactor’s feedstock was 52.25% and 82.4% respectively. The airflow rate was 10 lpm. After biodrying was done, the final moisture content of the feedstock from Reactor C was 22.0% and the final volatile solid content was 75.9%.The final calorific value after biodrying process was 3179,28kcal/kg.

Use of hydrodynamic disintegration to accelerate anaerobic digestion of surplus activated sludge.

PubMed

Grübel, Klaudiusz; Machnicka, Alicja

2009-12-01

Hydrodynamic disintegration of activated sludge resulted in organic matter and polymers transfer from the solid phase into the liquid phase. Disintegration by hydrodynamic cavitation had a positive effect on the degree and rate of excess sludge anaerobic digestion. Also, addition of a part of anaerobic digested sludge containing adapted microorganisms resulted in acceleration of the process. The disruption of cells of foam microorganisms and addition to the digestion process led to an increase of biogas production.

Short-term bioassay responses to sludge products and leachate.

PubMed

Fjällborg, B; Gustafsson, N

2006-10-01

Recycling of sewage sludge is needed in a sustainable society. Quality aspects of sludge include hygiene (pathogens), nutrients (N and P), and toxicants (metals and organics). Metals are of particular concern because they are not degradable, but their hazards are related to their bioavailability and chemical speciation. In this article, the effect on sludge quality of two treatment methods, incineration and pelletization, has been determined for digested sludge from two treatment plants. The combined effect of nutrients and toxicants in sludge and sludge product was determined for spring wheat, Triticum aestivum, and the toxicity of the leachate water was determined for water fleas, Daphnia magna, and seeds of lettuce, Lactuca sativa. Toxicity Identification Evaluation was used to determine whether metals were possible toxicants. The results indicated that incineration decreased toxicity, whereas leachability of metals and the fertilizing effect was unaffected. Pelletization seemed to increase toxicity and leachability of metals and also decreased the fertilizing effect of the sludge. Thus, the results suggest that pelletization of digested sewage sludge increased the toxicity of the sludge and thus decreased the quality of the sludge, whereas incineration apparently reduced toxicity for the two sludges tested.

Effects of biochar on nitrogen transformation and heavy metals in sludge composting.

PubMed

Liu, Wei; Huo, Rong; Xu, Junxiang; Liang, Shuxuan; Li, Jijin; Zhao, Tongke; Wang, Shutao

2017-07-01

Composting is regarded as an effective treatment to suppress pathogenic organisms and stabilize the organic material in sewage sludge. This study investigated the use of biochar as an amendment to improve the composting effectiveness and reduce the bioavailability of heavy metals and loss of nitrogen during composting. Biochar of 0%, 1%, 3%, 5% and 7% were added into a mixture of sludge and straw, respectively. The use of biochar, even in small amounts, altered the composting process and the properties of the end products. Biochar addition resulted in a higher pile temperature (66°C) and could reduce nitrogen loss by transforming ammonium into nitrite. In the 5% biochar group, the final product from sludge composting, ammonia nitrogen, decreased by 22.4% compared to the control, and nitrate nitrogen increased by 310.6%. Considering temperature and N transformation, the treatment with 5% biochar is suggested for sludge composting. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of organic calcium compounds on combustion characteristics of rice husk, sewage sludge, and bituminous coal: thermogravimetric investigation.

PubMed

Zhang, Lihui; Duan, Feng; Huang, Yaji

2015-04-01

Experiments were conducted in a thermogravimetric analyzer to assess the enhancement of combustion characteristics of different solid fuels blended with organic calcium compounds (OCCs). Rice husk, sewage sludge, and bituminous coal, and two OCC were used in this study. Effect of different mole ratios of calcium to sulfur (Ca/S ratio) on the combustion characteristics were also investigated. Results indicated that combustion performance indexes for bituminous coal impregnated by OCC were improved, however, an inverse trend was found for sewage sludge because sewage sludge has lower ignition temperature and higher volatile matter content compared to those of OCC. For rice husk, effect of added OCC on the combustion characteristics is not obvious. Different solid fuels show different combustion characteristics with increases of Ca/S ratio. The maximum combustion performance indexes appear at Ca/S ratios of 1:1, 2:1, and 3:1 for OCC blended with Shenhua coal, rice husk, and sewage sludge, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cocomposting with and without Eisenia fetida for conversion of toxic paper mill sludge to a soil conditioner.

PubMed

Kaur, Arvinder; Singh, Jaswinder; Vig, Adarsh Pal; Dhaliwal, S S; Rup, Pushpinder J

2010-11-01

Present study was envisaged for fast bioremediation of toxic paper mill sludge into a soil ameliorating agent. Although a rich source of organic carbon this sludge cannot be directly applied in fields and is recycled very slowly in landfills as it is deficient in other nutrients. Therefore it was mixed with cattle dung in various proportions and subjected to aerobic cocomposting (without worms) and vermicocomposting (with Eisenia fetida). It was observed that mixing cattle dung with the sludge improved physico-chemical characteristics (with transition metals in the permissible range for manures) of the products of both the processes and enhanced its acceptability for worms. Higher decline in organic carbon and higher content of nitrogen and phosphorous along with lower electrical conductivity and higher pH of the products of vermicomposting indicated that E. fetida helped in fast conversion of toxic paper mill sludge into a soil conditioner in 100days. Copyright 2010 Elsevier Ltd. All rights reserved.

Effects of total solids content on waste activated sludge thermophilic anaerobic digestion and its sludge dewaterability.

PubMed

Wang, Tianfeng; Chen, Jie; Shen, Honglang; An, Dong

2016-10-01

The role of total solids content on sludge thermophilic anaerobic digestion was investigated in batch reactors. A range of total solids content from 2% to 10% was evaluated with two replicates. The lowest inhibitory concentration for free ammonia and total ammonia of sludge thermophilic anaerobic digestion was 110.9-171.4mg/L and 1313.1-1806.7mg/L, respectively. The volumetric biogas production rate increased with increasing of total solids content, but the corresponding biogas yield per gram volatile solid decreased. The result of normalized capillary suction time indicated that the dewaterability of digested sludge at high total solids content was poor, while solid content of sediment obtained by centrifuging sludge at 2000g for 10min increased with increasing of total solids content of sludge. The results suggest that thickened sludge mixed with dewatered sludge at an appropriate ratio could get high organic loading rate, high biogas yield and adequate dewatering effort. Copyright © 2016 Elsevier Ltd. All rights reserved.

Change in the fouling propensity of sludge in membrane bioreactors (MBR) in relation to the accumulation of biopolymer clusters.

PubMed

Sun, Fei-yun; Wang, Xiao-mao; Li, Xiao-yan

2011-04-01

A membrane bioreactor (MBR) and an activated sludge process (ASP) were operated side by side to evaluate the change of sludge supernatant characteristics and the evolution of the sludge fouling propensity. The MBR sludge had a higher organic concentration and more biopolymer clusters (BPC) in the supernatant compared with ASP. BPC increased in both concentration and size in the MBR. The results show that the change in the liquid-phase property had a profound effect on the sludge fouling propensity. MBR operation transformed typical activated sludge to MBR sludge with a higher fouling propensity. Distinct from the ASP, membrane filtration retained soluble microbial products (SMP) within the MBR, and the vast membrane surface provided a unique environment for the transformation of SMP to large size BPC, leading to further sludge deposition on the membrane surface. Thus, membrane filtration is the crucial cause of the inevitable fouling problem in submerged MBRs. Copyright © 2011 Elsevier Ltd. All rights reserved.

Actual waste demonstration of the nitric-glycolic flowsheet for sludge batch 9 qualification

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

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

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. Based on the results of this actual-waste qualification and previous simulant studies, SRNL recommends implementation of the nitric-glycolic acid flowsheet in DWPF. Other recommendations resulting from this demonstration are reported in section 5.0.

Anaerobic/oxic/anoxic granular sludge process as an effective nutrient removal process utilizing denitrifying polyphosphate-accumulating organisms.

PubMed

Kishida, Naohiro; Kim, Juhyun; Tsuneda, Satoshi; Sudo, Ryuichi

2006-07-01

In a biological nutrient removal (BNR) process, the utilization of denitrifying polyphosphate-accumulating organisms (DNPAOs) has many advantages such as effective use of organic carbon substrates and low sludge production. As a suitable process for the utilization of DNPAOs in BNR, an anaerobic/oxic/anoxic granular sludge (AOAGS) process was proposed in this study. In spite of performing aeration for nitrifying bacteria, the AOAGS process can create anaerobic/anoxic conditions suitable for the cultivation of DNPAOs because anoxic zones exist inside the granular sludge in the oxic phase. Thus, DNPAOs can coexist with nitrifying bacteria in a single reactor. In addition, the usability of DNPAOs in the reactor can be improved by adding the anoxic phase after the oxic phase. These characteristics enable the AOAGS process to attain effective removal of both nitrogen and phosphorus. When acetate-based synthetic wastewater (COD: 600 mg/L, NH4-N: 60 mg/L, PO(4)-P: 10 mg/L) was supplied to a laboratory-scale sequencing batch reactor under the operation of anaerobic/oxic/anoxic cycles, granular sludge with a diameter of 500 microm was successfully formed within 1 month. Although the removal of both nitrogen and phosphorus was almost complete at the end of the oxic phase, a short anoxic period subsequent to the oxic phase was necessary for further removal of nitrogen and phosphorus. As a result, effluent concentrations of NH(4)-N, NO(x)-N and PO(4)-P were always lower than 1 mg/L. It was found that penetration depth of oxygen inside the granular sludge was approximately 100 microm by microsensor measurements. In addition, from the microbiological analysis by fluorescence in situ hybridization, existence depth of polyphosphate-accumulating organisms was further than the maximum oxygen penetration depth. The water quality data, oxygen profiles and microbial community structure demonstrated that DNPAOs inside the granular sludge may be responsible for denitrification in the oxic phase, which enables effective nutrient removal in the AOAGS process.

The stabilization of tannery sludge and the character of humic acid-like during low temperature pyrolysis.

PubMed

Ma, Hongrui; Gao, Mao; Hua, Li; Chao, Hao; Xu, Jing

2015-11-01

Tannery sludge contained plenty of organic matter, and the organic substance stability had direct impact on its derived chars' utilization. In this paper, the stabilization of tannery sludge and the variation of humic acid-like (HAL) extracted by different methods were investigated in a magnetic stirring reactor under low temperature pyrolysis of 100-400 °C. Results showed that the aromatic structure of pyrolysis chars increased with the increase of temperature and time. The char contained highly aromatic structure and relatively small dissolved organic matters (DOM) at 300 °C. The similar behaviors appeared in two HAL series by different extraction methods. The N content, H/C value, and aliphatic structures of HAL decreased with the increase of pyrolysis temperature, while the C/N value and aromatic structures increased with the rise of pyrolysis temperature. The composition and functional groups of HAL were similar with the purchased humic acid (HA). The fluorescence spectra revealed that two main peaks were found at Ex/Em = 239/363-368 nm and 283/359-368 nm in each HAL series from raw and 100 °C pyrolysis tannery sludge, representing a protein-like matter. The new peak appeared at Ex/Em = 263-283/388 nm in each HAL series from 200 °C pyrolysis tannery sludge-represented humic acid-like matter. The fluorescence intensity increased strongly compared to the other two peak intensity. Therefore, the humification of organic matter was increased by pyrolyzing. Notably, the HAL from 200 °C pyrolysis tannery sludge contained simple molecular structure, and the polycondensation increased but with a relative lower humification degree compared to soil HAL and purchased HA. Therefore, the sludge needs further oxidation. The humic substance was negligible by direct extraction when the temperature was 300 and 400 °C.

Electroplating sludge derived zinc-ferrite catalyst for the efficient photo-Fenton degradation of dye.

PubMed

Cao, Zhenbang; Zhang, Jia; Zhou, Jizhi; Ruan, Xiuxiu; Chen, Dan; Liu, Jianyong; Liu, Qiang; Qian, Guangren

2017-05-15

A zinc-dominant ferrite catalyst for efficient degradation of organic dye was prepared by the calcination of electroplating sludge (ES). Characterizations indicated that zinc ferrite (ZnFe 2 O 4 ) coexisted with Fe 2 O 3 structure was the predominant phase in the calcined electroplating sludge (CES). CES displayed a high decolorization ratio (88.3%) of methylene blue (MB) in the presence of H 2 O 2 combined with UV irradiation. The high efficiency could be ascribed to the photocatalytic process induced by ZnFe 2 O 4 and the photo-Fenton dye degradation by ferrous content, and a small amount of Al and Mg in the sludge might also contribute to the catalysis. Moreover, the degradation capability of dye by CES was supported by the synthetic ZnFe 2 O 4 with different Zn to Fe molar ratio (n(Zn): n(Fe)), as 84.81%-86.83% of dye was removed with n(Zn): n(Fe) ranged from 1:0.5 to 1:3. All synthetic ferrite samples in the simulation achieved adjacent equilibrium decolorization ratio, the flexible proportioning of divalent metal ions (M 2+ ) to trivalent metal ions (M 3+ ) applied in the synthesis indicated that the catalyst has a high availability. Therefore, an efficacious catalyst for the degradation of dye can potentially be derived from heavy metal-containing ES, it's a novel approach for the reutilization of ES. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhancement of the sludge disintegration and nutrients release by a treatment with potassium ferrate combined with an ultrasonic process.

PubMed

Li, Wei; Yu, Najiaowa; Liu, Qian; Li, Yiran; Ren, Nanqi; Xing, Defeng

2018-09-01

Sludge disintegration by ultrasound is a promising sludge treatment method. In order to enhance the efficiency of the sludge reduction and hydrolysis, potassium ferrate (K 2 FeO 4 ) (PF) was used. A novel method was developed to improve the sludge disintegration-sludge pretreatment by using PF in combination with an ultrasonic treatment (PF + ULT). After a short-term PF + ULT treatment, 17.23% of the volatile suspended solids (VSS) were reduced after a 900-min reaction time, which is 61.3% higher than the VSS reduction for the raw sludge. The supernatant soluble chemical oxygen demand (SCOD), total nitrogen (TN), volatile fatty acids (VFAs), soluble protein and polysaccharides increased by 522.5%, 1029.4%, 878.4%, 2996.6% and 801.9%, respectively. The constituent parts of the dissolved organic matter of the sludge products were released efficiently, which demonstrated the positive effect caused by the PF + ULT. The enhanced sludge disintegration process further alleviates environmental risk and offers a more efficient and convenient method for utilizing sludge. Copyright © 2018 Elsevier B.V. All rights reserved.

Accumulation of Cr, Cd, Pb, Cu, and Zn by plants in tanning sludge storage sites: opportunities for contamination bioindication and phytoremediation

USDA-ARS?s Scientific Manuscript database

The lack of appropriate disposal strategies of tanning sludge (e.g., uncontrolled landfills and disposing sludge to open areas) has led to severe Cr pollution in waters and soils in many developing countries. Excessive Cr can be highly toxic to many living organisms and may damage the ecosystem. In ...

Investigation of organic nitrogen and carbon removal in the aerobic digestion of various sludges.

PubMed

Genç, Nevim; Yonsel, Sems; Dağaşan, Levent; Onar, A N

2002-11-01

Nitrification and carbon removal are investigated in aerobic batch digestion of various sludges. The experiments are carried out with activated sludge (Test 1) and with a mixture of activated and primary settling sludge (Test 2). The nitrification rate was monitored, measuring the NO2- concentration. At the 3rd day of the digestion 40.7 mgNO2-N/l and 3.89 mgNO2-N/l were found in Tests 1 and 2 respectively. In a digestion process, the degradation of biomass indicates the beginning of the endogenous phase. Our measure for biomass content of the sludge was protein analysis. In Test 1, the first day values of 50.93 mgTOC/ g(dry) matter/day and 138.53 mg(protein)-C/g(dry) matter/day for specific TOC and protein-C removal rates showed, that the digestion process began in the endogenous phase. For Test 2, since the endogenous phase began after removal of raw organic matter in primary settling sludge, specific TOC and protein-C removal rates were observed to be 60.12 mgTOC/g(dry) matter/day and 26.72 mg(protein-C/g(dry)matter/day, respectively.

Evaluation of the Removal of Indicator Bacteria from Domestic Sludge Processed by Autothermal Thermophilic Aerobic Digestion (ATAD)

PubMed Central

Piterina, Anna V.; Bartlett, John; Pembroke, Tony J.

2010-01-01

The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD) processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen) and fecal-coliform (indicator) densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing. PMID:20948933

Evaluation of the removal of indicator bacteria from domestic sludge processed by Autothermal Thermophilic Aerobic Digestion (ATAD).

PubMed

Piterina, Anna V; Bartlett, John; Pembroke, Tony J

2010-09-01

The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD) processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen) and fecal-coliform (indicator) densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing.

The Effect of paper mill waste and sewage sludge amendments on soil organic matter

NASA Astrophysics Data System (ADS)

Méndez, Ana; Barriga, Sandra; Guerrero, Francisca; Gascó, Gabriel

2013-04-01

In general, Mediterranean soils have low organic matter content, due to the climate characteristics of this region and inadequate land management. Traditionally, organic wastes such as manure are used as amendment in order to improve the soil quality, increasing soil fertility by the accumulation of nitrogen, phosphorus and other plant nutrients in the soil. In the last decade, other anthropogenic organic wastes such as sewage sludge or paper waste materials have been studied as soil amendments to improve physical, chemical and biological properties of soils. The objective of the present work was to study the influence of waste from a paper mill and sewage sludge amendments on soil organic matter. For this reason, soil organic matter evolution was studied using thermogravimetric analysis (TGA), the derivative (dTG) and differential thermal analysis (DTA). Thermal analytical techniques have the advantage of using full samples without pre-treatments and have been extensively used to study the evolution of organic matter in soils, to evaluate composting process or to study the evolution of organic matter of growing media.

Influence of pyrolysis temperature on composted sewage sludge biochar priming effect in a loamy soil.

PubMed

Méndez, A; Tarquis, A M; Saa-Requejo, A; Guerrero, F; Gascó, G

2013-10-01

Biochar is a carbon-rich solid product obtained by the pyrolysis of organic materials. The carbon stability of biochar allows that it can be applied to soil for long-term carbon storage. This carbon stability is greatly influenced by the pyrolysis temperature and the raw material used for biochar production. The aim of the present work is to study the soil carbon sequestration after the application of biochar from sewage sludge (SL) pyrolysis at two different temperatures (400 and 600 °C). For this purpose, soil CO2 emissions were measured for 80 d in an incubation experiment after soil amendment with the SL and each biochar at a dosage of 8 wt%. Biochar reduced the CO2 emissions during incubation between 11% and 32% relative to the SL treatment. The CO2 data were fit to a dual exponential model, and the CO2 emissions were simulated at different times (1, 5 and 10 yr). Additionally, the kinetics of the CO2 evolution from SL, two biochar samples, soil and amended soil were well fit to a dual first-order kinetic model with correlation coefficients greater than 0.93. The simulation of CO2 emissions from the soil by applying the proposed double first-order kinetic model (kg CO2-C ha(-1)) showed a reduction of CO2 emissions between 301 and 932 kg CO2-C ha(-1)with respect to the direct application of raw sewage sludge after 10 yr. Copyright © 2013 Elsevier Ltd. All rights reserved.

Recommendation of ruthenium source for sludge batch flowsheet studies

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

Woodham, W.

Included herein is a preliminary analysis of previously-generated data from sludge batches 7a, 7b, 8, and 9 sludge simulant and real-waste testing, performed to recommend a form of ruthenium for future sludge batch simulant testing under the nitric-formic flowsheet. Focus is given to reactions present in the Sludge Receipt and Adjustment Tank cycle, given that this cycle historically produces the most changes in chemical composition during Chemical Process Cell processing. Data is presented and analyzed for several runs performed under the nitric-formic flowsheet, with consideration given to effects on the production of hydrogen gas, nitrous oxide gas, consumption of formate,more » conversion of nitrite to nitrate, and the removal and recovery of mercury during processing. Additionally, a brief discussion is given to the effect of ruthenium source selection under the nitric-glycolic flowsheet. An analysis of data generated from scaled demonstration testing, sludge batch 9 qualification testing, and antifoam degradation testing under the nitric-glycolic flowsheet is presented. Experimental parameters of interest under the nitric-glycolic flowsheet include N2O production, glycolate destruction, conversion of glycolate to formate and oxalate, and the conversion of nitrite to nitrate. To date, the number of real-waste experiments that have been performed under the nitric-glycolic flowsheet is insufficient to provide a complete understanding of the effects of ruthenium source selection in simulant experiments with regard to fidelity to real-waste testing. Therefore, a determination of comparability between the two ruthenium sources as employed under the nitric-glycolic flowsheet is made based on available data in order to inform ruthenium source selection for future testing under the nitric-glycolic flowsheet.« less

Comparison of three different wastewater sludge and their respective drying processes: Solar, thermal and reed beds - Impact on organic matter characteristics.

PubMed

Collard, Marie; Teychené, Benoit; Lemée, Laurent

2017-12-01

Drying process aims at minimising the volume of wastewater sludge (WWS) before disposal, however it can impact sludge characteristics. Due to its high content in organic matter (OM) and lipids, sludge are mainly valorised by land farming but can also be considered as a feedstock for biodiesel production. As sludge composition is a major parameter for the choice of disposal techniques, the objective of this study was to determine the influence of the drying process. To reach this goal, three sludges obtained from solar, reed beds and thermal drying processes were investigated at the global and molecular scales. Before the drying step the sludges presented similar physico-chemical (OM content, elemental analysis, pH, infrared spectra) characteristics and lipid contents. A strong influence of the drying process on lipids and humic-like substances contents was observed through OM fractionation. Thermochemolysis-GCMS of raw sludge and lipids revealed similar molecular content mainly constituted with steroids and fatty acids. Molecular changes were noticeable for thermal drying through differences in branched to linear fatty acids ratio. Finally the thermal drying induced a weakening of OM whereas the solar drying led to a complexification. These findings show that smooth drying processes such as solar or reed-beds are preferable for amendment production whereas thermal process leads to pellets with a high lipid content which could be considered for fuel production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Odor composition analysis and odor indicator selection during sewage sludge composting

PubMed Central

Zhu, Yan-li; Zheng, Guo-di; Gao, Ding; Chen, Tong-bin; Wu, Fang-kun; Niu, Ming-jie; Zou, Ke-hua

2016-01-01

ABSTRACT On the basis of total temperature increase, normal dehydration, and maturity, the odor compositions of surface and internal piles in a well-run sewage sludge compost plant were analyzed using gas chromatography–mass spectrometry with a liquid nitrogen cooling system and a portable odor detector. Approximately 80 types of substances were detected, including 2 volatile inorganic compounds, 4 sulfur organic compounds, 16 benzenes, 27 alkanes, 15 alkenes, and 19 halogenated compounds. Most pollutants were mainly produced in the mesophilic and pre-thermophilic periods. The sulfur volatile organic compounds contributed significantly to odor and should be controlled primarily. Treatment strategies should be based on the properties of sulfur organic compounds. Hydrogen sulfide, methyl mercaptan, dimethyl disulfide, dimethyl sulfide, ammonia, and carbon disulfide were selected as core indicators. Ammonia, hydrogen sulfide, carbon disulfide, dimethyl disulfide, methyl mercaptan, dimethylbenzene, phenylpropane, and isopentane were designated as concentration indicators. Benzene, m-xylene, p-xylene, dimethylbenzene, dichloromethane, toluene, chlorobenzene, trichloromethane, carbon tetrachloride, and ethylbenzene were selected as health indicators. According to the principle of odor pollution indicator selection, dimethyl disulfide was selected as an odor pollution indicator of sewage sludge composting. Monitoring dimethyl disulfide provides a highly scientific method for modeling and evaluating odor pollution from sewage sludge composting facilities. Implications: Composting is one of the most important methods for sewage sludge treatment and improving the low organic matter content of many agricultural soils. However, odors are inevitably produced during the composting process. Understanding the production and emission patterns of odors is important for odor control and treatment. Core indicators, concentration indicators, and health indicators provide an index system to odor evaluation. An odor pollution indicator provides theoretical support for further modelling and evaluating odor pollution from sewage sludge composting facilities. PMID:27192607

Odor composition analysis and odor indicator selection during sewage sludge composting.

PubMed

Zhu, Yan-Li; Zheng, Guo-di; Gao, Ding; Chen, Tong-Bin; Wu, Fang-Kun; Niu, Ming-Jie; Zou, Ke-Hua

2016-09-01

On the basis of total temperature increase, normal dehydration, and maturity, the odor compositions of surface and internal piles in a well-run sewage sludge compost plant were analyzed using gas chromatography-mass spectrometry with a liquid nitrogen cooling system and a portable odor detector. Approximately 80 types of substances were detected, including 2 volatile inorganic compounds, 4 sulfur organic compounds, 16 benzenes, 27 alkanes, 15 alkenes, and 19 halogenated compounds. Most pollutants were mainly produced in the mesophilic and pre-thermophilic periods. The sulfur volatile organic compounds contributed significantly to odor and should be controlled primarily. Treatment strategies should be based on the properties of sulfur organic compounds. Hydrogen sulfide, methyl mercaptan, dimethyl disulfide, dimethyl sulfide, ammonia, and carbon disulfide were selected as core indicators. Ammonia, hydrogen sulfide, carbon disulfide, dimethyl disulfide, methyl mercaptan, dimethylbenzene, phenylpropane, and isopentane were designated as concentration indicators. Benzene, m-xylene, p-xylene, dimethylbenzene, dichloromethane, toluene, chlorobenzene, trichloromethane, carbon tetrachloride, and ethylbenzene were selected as health indicators. According to the principle of odor pollution indicator selection, dimethyl disulfide was selected as an odor pollution indicator of sewage sludge composting. Monitoring dimethyl disulfide provides a highly scientific method for modeling and evaluating odor pollution from sewage sludge composting facilities. Composting is one of the most important methods for sewage sludge treatment and improving the low organic matter content of many agricultural soils. However, odors are inevitably produced during the composting process. Understanding the production and emission patterns of odors is important for odor control and treatment. Core indicators, concentration indicators, and health indicators provide an index system to odor evaluation. An odor pollution indicator provides theoretical support for further modelling and evaluating odor pollution from sewage sludge composting facilities.

Assessment of biogas production in Argentina from co-digestion of sludge and municipal solid waste.

PubMed

Morero, Betzabet; Vicentin, Rocio; Campanella, Enrique A

2017-03-01

In Argentina, there is an important potential to utilize organic waste to generate bioenergy. This work analyzes the environmental impacts and the energetic and economic requirements of the biogas produced by digesting the sewage sludge (SS) produced in a wastewater treatment plant in a medium city in Argentina. The SS is co-digested with the organic fraction of municipal solid waste (OFMSW), and the basis of this study is the life cycle assessment (LCA). The LCA is performed according to ISO 14040-44 using the SimaPro simulator. First, the transport of the raw materials to the biogas plant was defined. Then, the co-digestion and the biogas treatment for final use were evaluated. The co-digestion was improved with glycerol, and the generation of biogas was estimated using the GPS-X software. Two alternatives for the end use of biogas were considered: combined heat and power (CHP) and biomethane generation. For the first, H 2 S and water vapor were removed from the raw biogas stream, and for the second, also CO 2 was removed. The H 2 S removal process was simulated in the SuperPro software by anaerobic biofiltration. The same software was used to simulate the removal of CO 2 absorption-desorption with water as solvent. Finally, the environmental impacts related to the end use of biogas (CHP and biomethane) were evaluated. The environmental, energetic and economic analyses showed that the co-digestion of SS and OFMSW has great potential for reducing the environmental impacts and increasing the economic and energetic value of the substances via the production of biomethane, electricity and, potentially, fertilizer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Experimental evaluation of drying characteristics of sewage sludge and hazelnut shell mixtures

NASA Astrophysics Data System (ADS)

Pehlivan, Hüseyin; Ateş, Asude; Özdemir, Mustafa

2016-11-01

In this study the drying behavior of organic and agricultural waste mixtures has been experimentally investigated. The usability of sewage sludge as an organic waste and hazelnut shell as an agricultural waste was assessed in different mixture range. The paper discusses the applicability of these mixtures as a recovery energy source. Moisture content of mixtures has been calculated in laboratory and plant conditions. Indoor and outdoor solar sludge drying plants were constructed in pilot scale for experimental purposes. Dry solids and climatic conditions were constantly measured. A total more than 140 samples including for drying has been carried out to build up results. Indoor and outdoor weather conditions are taken into consideration in winter and summer. The most effective drying capacity is obtained in mixture of 20 % hazelnut shell and 80 % sewage sludge.

Nitrogen mineralization from sludge in an alkaline, saline coal gasification ash environment.

PubMed

Mbakwe, Ikenna; De Jager, Pieter C; Annandale, John G; Matema, Taurai

2013-01-01

Rehabilitating coal gasification ash dumps by amendment with waste-activated sludge has been shown to improve the physical and chemical properties of ash and to facilitate the establishment of vegetation. However, mineralization of organic N from sludge in such an alkaline and saline medium and the effect that ash weathering has on the process are poorly understood and need to be ascertained to make decisions regarding the suitability of this rehabilitation option. This study investigated the rate and pattern of N mineralization from sludge in a coal gasification ash medium to determine the prevalent inorganic N form in the system and assess the effect of ash weathering on N mineralization. An incubation experiment was performed in which fresh ash, weathered ash, and soil were amended with the equivalent of 90 Mg ha sludge, and N mineralization was evaluated over 63 d. More N (24%) was mineralized in fresh ash than in weathered ash and soil, both of which mineralized 15% of the initial organic N in sludge. More nitrification occurred in soil, and most of the N mineralized in ash was in the form of ammonium, indicating an inhibition of nitrifying organisms in the ash medium and suggesting that, at least initially, plants used for rehabilitation of coal gasification ash dumps will take up N mostly as ammonium. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Sewage sludge open-air drying affects on keratinolytic, keratinophilic and actidione-resistant fungi.

PubMed

Ulfig, Krzysztof; Płaza, Grazyna; Terakowskip, Maciej; Janda-Ulfig, Katarzyna

2006-01-01

The study was to demonstrate the effect of sewage sludge open-air drying on the quantitative and qualitative composition of keratinolytic/keratinophilic and actidione-resistant fungi. The sludge was being dried for up to thirty days (on average fourteen days) at 25-30'C. The composition of these fungi was determined with the hair baiting method along with the dilution method, using the Wiegand medium supplemented with chloramphenicol (100 mgiL) and actidione (500 mg/L). The open-air drying altered the composition of keratinolytic fungi and considerably increased the population of keratinophilic and actidione-resistant fungi in the sludge. This phenomenon can be explained with that the drying process was associated with slow sludge moisture decrease, sludge laceration due to crumbling and the subsequent improvement of sludge aeration and organic matter biodegradation conditions. A considerable increase of fungal populations can be expected in sludges being dried in drying beds at wastewater treatment plants and in sludge-amended soils. Two sludge opportunistic fungi, i.e. Microsporum gypseum and Pseudallescheria boydii, require special attention from the epidemiological point of view. Sludge land applications may increase the number of these fungi in the environment and the subsequent risk to public health posed by them.

Optimization of MBR hydrodynamics for cake layer fouling control through CFD simulation and RSM design.

PubMed

Yang, Min; Yu, Dawei; Liu, Mengmeng; Zheng, Libing; Zheng, Xiang; Wei, Yuansong; Wang, Fang; Fan, Yaobo

2017-03-01

Membrane fouling is an important issue for membrane bioreactor (MBR) operation. This paper aims at the investigation and the controlling of reversible membrane fouling due to cake layer formation and foulants deposition by optimizing MBR hydrodynamics through the combination of computational fluid dynamics (CFD) and design of experiment (DOE). The model was validated by comparing simulations with measurements of liquid velocity and dissolved oxygen (DO) concentration in a lab-scale submerged MBR. The results demonstrated that the sludge concentration is the most influencing for responses including shear stress, particle deposition propensity (PDP), sludge viscosity and strain rate. A medium sludge concentration of 8820mgL -1 is optimal for the reduction of reversible fouling in this submerged MBR. The bubble diameter is more decisive than air flowrate for membrane shear stress due to its role in sludge viscosity. The optimal bubble diameter was at around 4.8mm for both of shear stress and PDP. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prediction of anaerobic biodegradability and bioaccessibility of municipal sludge by coupling sequential extractions with fluorescence spectroscopy: towards ADM1 variables characterization.

PubMed

Jimenez, Julie; Gonidec, Estelle; Cacho Rivero, Jesús Andrés; Latrille, Eric; Vedrenne, Fabien; Steyer, Jean-Philippe

2014-03-01

Advanced dynamic anaerobic digestion models, such as ADM1, require both detailed organic matter characterisation and intimate knowledge of the involved metabolic pathways. In the current study, a methodology for municipal sludge characterization is investigated to describe two key parameters: biodegradability and bioaccessibility of organic matter. The methodology is based on coupling sequential chemical extractions with 3D fluorescence spectroscopy. The use of increasingly strong solvents reveals different levels of organic matter accessibility and the spectroscopy measurement leads to a detailed characterisation of the organic matter. The results obtained from testing 52 municipal sludge samples (primary, secondary, digested and thermally treated) showed a successful correlation with sludge biodegradability and bioaccessibility. The two parameters, traditionally obtained through the biochemical methane potential (BMP) lab tests, are now obtain in only 5 days compared to the 30-60 days usually required. Experimental data, obtained from two different laboratory scale reactors, were used to validate the ADM1 model. The proposed approach showed a strong application potential for reactor design and advanced control of anaerobic digestion processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Modeling of the reburning process using sewage sludge-derived syngas

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

Werle, Sebastian, E-mail: sebastian.werle@polsl.pl

2012-04-15

Highlights: Black-Right-Pointing-Pointer Gasification provides an attractive method for sewage sludges treatment. Black-Right-Pointing-Pointer Gasification generates a fuel gas (syngas) which can be used as a reburning fuel. Black-Right-Pointing-Pointer Reburning potential of sewage sludge gasification gases was defined. Black-Right-Pointing-Pointer Numerical simulation of co-combustion of syngases in coal fired boiler has been done. Black-Right-Pointing-Pointer Calculation shows that analysed syngases can provide higher than 80% reduction of NO{sub x}. - Abstract: Gasification of sewage sludge can provide clean and effective reburning fuel for combustion applications. The motivation of this work was to define the reburning potential of the sewage sludge gasification gas (syngas). Amore » numerical simulation of the co-combustion process of syngas in a hard coal-fired boiler was done. All calculations were performed using the Chemkin programme and a plug-flow reactor model was used. The calculations were modelled using the GRI-Mech 2.11 mechanism. The highest conversions for nitric oxide (NO) were obtained at temperatures of approximately 1000-1200 K. The combustion of hard coal with sewage sludge-derived syngas reduces NO emissions. The highest reduction efficiency (>90%) was achieved when the molar flow ratio of the syngas was 15%. Calculations show that the analysed syngas can provide better results than advanced reburning (connected with ammonia injection), which is more complicated process.« less

Modified ADM1 for modeling free ammonia inhibition in anaerobic acidogenic fermentation with high-solid sludge.

PubMed

Bai, Jie; Liu, He; Yin, Bo; Ma, Huijun; Chen, Xinchun

2017-02-01

Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid (VFA) production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1 (ADM1) was modified to simulate the VFA generation in batch, semi-continuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0. Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms, were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the K s of acetate is 0.025, the k m,ac is 12.51, and the K I_NH3 is 0.02, respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30m 3 full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation. Copyright © 2016. Published by Elsevier B.V.

Fossil organic carbon in wastewater and its fate in treatment plants.

PubMed

Law, Yingyu; Jacobsen, Geraldine E; Smith, Andrew M; Yuan, Zhiguo; Lant, Paul

2013-09-15

This study reports the presence of fossil organic carbon in wastewater and its fate in wastewater treatment plants. The findings pinpoint the inaccuracy of current greenhouse gas accounting guidelines which defines all organic carbon in wastewater to be of biogenic origin. Stable and radiocarbon isotopes ((13)C and (14)C) were measured throughout the process train in four municipal wastewater treatment plants equipped with secondary activated sludge treatment. Isotopic mass balance analyses indicate that 4-14% of influent total organic carbon (TOC) is of fossil origin with concentrations between 6 and 35 mg/L; 88-98% of this is removed from the wastewater. The TOC mass balance analysis suggests that 39-65% of the fossil organic carbon from the influent is incorporated into the activated sludge through adsorption or from cell assimilation while 29-50% is likely transformed to carbon dioxide (CO2) during secondary treatment. The fossil organic carbon fraction in the sludge undergoes further biodegradation during anaerobic digestion with a 12% decrease in mass. 1.4-6.3% of the influent TOC consists of both biogenic and fossil carbon is estimated to be emitted as fossil CO2 from activated sludge treatment alone. The results suggest that current greenhouse gas accounting guidelines, which assume that all CO2 emission from wastewater is biogenic may lead to underestimation of emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cobalt sorption onto anaerobic granular sludge: isotherm and spatial localization analysis.

PubMed

van Hullebusch, Eric D; Gieteling, Jarno; Zhang, Min; Zandvoort, Marcel H; Daele, Wim Van; Defrancq, Jacques; Lens, Piet N L

2006-01-24

This study investigated the effect of different feeding regimes on the cobalt sorption capacity of anaerobic granular sludge from a full-scale bioreactor treating paper mill wastewater. Adsorption experiments were done with non-fed granules in monometal (only Co) and competitive conditions (Co and Ni in equimolar concentrations). In order to modify the extracellular polymeric substances and sulfides content of the granules, the sludge was fed for 30 days with glucose (pH 7, 30 degrees C, organic loading rate=1.2 g glucose l(-1) day-1) in the presence (COD/SO4(2-)=1) or absence of sulfate. The partitioning of the sorbed cobalt between the exchangeable, carbonates, organic matter/sulfides and residual fractions was determined using a sequential extraction procedure (modified Tessier). Experimental equilibrium sorption data for cobalt were analysed by the Langmuir, Freundlich and Redlich-Peterson isotherm equations. The total Langmuir maximal sorption capacity of the sludge fed with glucose and sulfate loaded with cobalt alone displayed a significantly higher maximal cobalt sorption (Qmax =18.76 mg g-1 TSS) than the sludge fed with glucose alone (Qmax =13.21 mg g-1 TSS), essentially due to an increased sorption capacity of the exchangeable (30-107%) and organic/sulfides fractions (70-30%). Environmental scanning electron microscopy coupled with an energy dispersive X-ray analysis of granular cross-sections showed that mainly iron minerals (i.e. iron sulfides) were involved in the cobalt accumulation. Moreover, the sorbed cobalt was mainly located at the edge of the granules. The sorption characteristics of the exchangeable and carbonates fractions fitted well to the Redlich-Peterson model (intermediate multi-layer sorption behaviour), whereas the sorption characteristics of the organic matter/sulfides and residual fractions fitted well to the Langmuir model (monolayer sorption behaviour). The organic matter/sulfides fraction displayed the highest affinity for cobalt for the three sludge types investigated.

Effects of dissolved oxygen on performance and microbial community structure in a micro-aerobic hydrolysis sludge in situ reduction process.

PubMed

Niu, Tianhao; Zhou, Zhen; Shen, Xuelian; Qiao, Weimin; Jiang, Lu-Man; Pan, Wei; Zhou, Jijun

2016-03-01

A sludge process reduction activated sludge (SPRAS), with a sludge process reduction module composed of a micro-aerobic tank and a settler positioned before conventional activated sludge process, showed good performance of pollutant removal and sludge reduction. Two SPRAS systems were operated to investigate effects of micro-aeration on sludge reduction performance and microbial community structure. When dissolved oxygen (DO) concentration in the micro-aerobic tank decreased from 2.5 (SPH) to 0.5 (SPL) mg/L, the sludge reduction efficiency increased from 42.9% to 68.3%. Compared to SPH, activated sludge in SPL showed higher contents of extracellular polymeric substances and dissolved organic matter. Destabilization of floc structure in the settler, and cell lysis in the sludge process reduction module were two major reasons for sludge reduction. Illumina-MiSeq sequencing showed that microbial diversity decreased under high DO concentration. Proteobacteria, Bacteroidetes and Chloroflexi were the most abundant phyla in the SPRAS. Specific comparisons down to the class and genus level showed that fermentative, predatory and slow-growing bacteria in SPL community were more abundant than in SPH. The results revealed that micro-aeration in the SPRAS improved hydrolysis efficiency and enriched fermentative and predatory bacteria responsible for sludge reduction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Technologies for reducing sludge production in wastewater treatment plants: State of the art.

PubMed

Wang, Qilin; Wei, Wei; Gong, Yanyan; Yu, Qiming; Li, Qin; Sun, Jing; Yuan, Zhiguo

2017-06-01

This review presents the state-of-the-art sludge reduction technologies applied in both wastewater and sludge treatment lines. They include chemical, mechanical, thermal, electrical treatment, addition of chemical un-coupler, and predation of protozoa/metazoa in wastewater treatment line, and physical, chemical and biological pretreatment in sludge treatment line. Emphasis was put on their effect on sludge reduction performance, with 10% sludge reduction to zero sludge production in wastewater treatment line and enhanced TS (total solids) or volatile solids removal of 5-40% in sludge treatment line. Free nitrous acid (FNA) technology seems good in wastewater treatment line but it is only under the lab-scale trial. In sludge treatment line, thermal, ultrasonic (<4400kJ/kg TS), FNA pretreatment and temperature-phased anaerobic digestion (TPAD) are promising if pathogen inactivation is not a concern. However, thermal pretreatment and TPAD are superior to other pretreatment technologies when pathogen inactivation is required. The new wastewater treatment processes including SANI®, high-rate activated sludge coupled autotrophic nitrogen removal and anaerobic membrane bioreactor coupled autotrophic nitrogen removal also have a great potential to reduce sludge production. In the future, an effort should be put on the effect of sludge reduction technologies on the removal of organic micropollutants and heavy metals. Copyright © 2017 Elsevier B.V. All rights reserved.

[Harvest of the carbon source in wastewater by the adsorption and desorption of activated sludge].

PubMed

Liu, Hong-Bo; Wen, Xiang-Hua; Zhao, Fang; Mei, Yi-Jun

2011-04-01

The carbon source in municipal wastewater was adsorbed by activated sludge and then harvested through the hydrolysis of activated sludge. Results indicated that activated sludge had high absorbing ability towards organic carbon and phosphorus under continuous operation mode, and the average COD and TP absorption rate reached as high as 63% and 76%, respectively. Moreover, about 50% of the soluble carbon source was outside of the sludge cell and could be released under mild hydrolysis condition. Whereas the absorbed amount of nitrogen was relatively low, and the removal rate of ammonia was only 13% . Furthermore, the releases of organic carbon, nitrogen and phosphorus from the sludge absorbing pollutants in the wastewater were studied. By comparing different hydrolysis conditions of normal (pH 7.5, 20 degrees C), heating (pH 7.5, 60 degrees C) and the alkaline heating (pH 11, 60 degrees C), the last one presented the optimum hydrolysis efficiency. Under which, the release rate of COD could reach 320 mg/g after 24 hours, whereas nitrogen and phosphorus just obtained low release rates of 18 mg/g and 2 mg/g, respectively. Results indicate that the carbon source in wastewater could be harvested by the adsorption and desorption of activated sludge, and the concentrations of nitrogen and phosphorus are low and would not influence the reuse of the harvested carbon source.

Disinfection of sewage wastewater and sludge by electron treatment

NASA Astrophysics Data System (ADS)

Trump, J. G.; Merrill, E. W.; Wright, K. A.

The use of machine-accelerated electrons to disinfect sewage waterwaste and sludge is discussed. The method is shown to be practical and energy-efficient for the broad spectrum disinfection of pathogenic organisms in municipal wastewaters and sludge removed from them. Studies of biological, chemical and physical effects are reported. Electron treatment is suggested as an alternative to chlorination of municipal liquid wastes after electron treatment to provide disinfection. Disposal of sewage sludge is recommended as an agricultural resource by subsurface land injection, or as a nutrient for fish populations by widespread ocean dispersal.

Sewage sludge dewatering using flowing liquid metals

DOEpatents

Carlson, Larry W.

1986-01-01

A method and apparatus for reducing the moisture content of a moist sewage sludge having a moisture content of about 50% to 80% and formed of small cellular micro-organism bodies having internally confined water is provided. A hot liquid metal is circulated in a circulation loop and the moist sewage sludge is injected in the circulation loop under conditions of temperature and pressure such that the confined water vaporizes and ruptures the cellular bodies. The vapor produced, the dried sludge, and the liquid metal are then separated. Preferably, the moist sewage sludge is injected into the hot liquid metal adjacent the upstream side of a venturi which serves to thoroughly mix the hot liquid metal and the moist sewage sludge. The venturi and the drying zone after the venturi are preferably vertically oriented. The dried sewage sludge recovered is available as a fuel and is preferably used for heating the hot liquid metal.

Comparison of Cross Flow Filtration Performance for Manganese Oxide/Sludge Mixtures and Monosodium Titanate/Sludge Mixtures

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

Poirier, M.R.

2002-06-07

Personnel performed engineering-scale tests at the Filtration Research Engineering Demonstration (FRED) to determine crossflow filter performance with a 5.6 M sodium solution containing varying concentrations of sludge and sodium permanganate. The work represents another in a series of collaborative efforts between the University of South Carolina and the Savannah River Technology Center in support of the process development efforts for the Savannah River Site. The current tests investigated filter performance with slurry containing simulated Tank 40H Sludge and sodium permanganate at concentrations between 0.070 weight percent and 3.04 weight percent insoluble solids.

Effects of application of mill-generated primary sludge and boiler ash on loblolly pine survival and growth

Treesearch

Emily J. Goodwin; Andrew M. Burrow

2006-01-01

Use of Kraft primary sludge and boiler ash in forest production systems holds promise as a cost-effective alternative to landfilling. From a soil quality perspective, particularly in coarse-textured sandy soils, increases in organic matter content from inputs of sludge/ash may improve soil chemical, biological, and physical properties. The objective of this study was...

The effect of toxic carbon source on the reaction of activated sludge in the batch reactor.

PubMed

Wu, Changyong; Zhou, Yuexi; Zhang, Siyu; Xu, Min; Song, Jiamei

2018-03-01

The toxic carbon source can cause higher residual effluent dissolved organic carbon than easily biodegraded carbon source in activated sludge process. In this study, an integrated activated sludge model is developed as the tool to understand the mechanism of toxic carbon source (phenol) on the reaction, regarding the carbon flows during the aeration period in the batch reactor. To estimate the toxic function of phenol, the microbial cells death rate (k death ) is introduced into the model. The integrated model was calibrated and validated by the experimental data and it was found the model simulations matched the all experimental measurements. In the steady state, the toxicity of phenol can result in higher microbial cells death rate (0.1637 h -1 vs 0.0028 h -1 ) and decay rate coefficient of biomass (0.0115 h -1 vs 0.0107 h -1 ) than acetate. In addition, the utilization-associated products (UAP) and extracellular polymeric substances (EPS) formation coefficients of phenol are higher than that of acetate, indicating that more carbon flows into the extracellular components, such as soluble microbial products (SMP), when degrading toxic organics. In the non-steady state of feeding phenol, the yield coefficient for growth and maximum specific growth rate are very low in the first few days (1-10 d), while the decay rate coefficient of biomass and microbial cells death rate are relatively high. The model provides insights into the difference of the dynamic reaction with different carbon sources in the batch reactor. Copyright © 2017 Elsevier Ltd. All rights reserved.

Extracellular protein analysis of activated sludge and their functions in wastewater treatment plant by shotgun proteomics.

PubMed

Zhang, Peng; Shen, Yu; Guo, Jin-Song; Li, Chun; Wang, Han; Chen, You-Peng; Yan, Peng; Yang, Ji-Xiang; Fang, Fang

2015-07-10

In this work, proteins in extracellular polymeric substances extracted from anaerobic, anoxic and aerobic sludges of wastewater treatment plant (WWTP) were analyzed to probe their origins and functions. Extracellular proteins in WWTP sludges were identified using shotgun proteomics, and 130, 108 and 114 proteins in anaerobic, anoxic and aerobic samples were classified, respectively. Most proteins originated from cell and cell part, and their most major molecular functions were catalytic activity and binding activity. The results exhibited that the main roles of extracellular proteins in activated sludges were multivalence cations and organic molecules binding, as well as in catalysis and degradation. The catalytic activity proteins were more widespread in anaerobic sludge compared with those in anoxic and aerobic sludges. The structure difference between anaerobic and aerobic sludges could be associated with their catalytic activities proteins. The results also put forward a relation between the macro characteristics of activated sludges and micro functions of extracellular proteins in biological wastewater treatment process.

Comparing alkaline and thermal disintegration characteristics for mechanically dewatered sludge.

PubMed

Tunçal, Tolga

2011-10-01

Thermal drying is one of the advanced technologies ultimately providing an alternative method of sludge disposal. In this study, the drying kinetics of mechanically dewatered sludge (MDS) after alkaline and thermal disintegration have been studied. In addition, the effect of total organic carbon (TOC) on specific resistance to filtration and sludge bound water content were also investigated on freshly collected sludge samples. The combined effect of pH and TOC on the thermal sludge drying rate for MDS was modelled using the two-factorial experimental design method. Statistical assessment of the obtained results proposed that sludge drying potential has increased exponentially for both increasing temperature and lime dosage. Execution of curve fitting algorithms also implied that drying profiles for raw and alkaline-disintegrated sludge were well fitted to the Henderson and Pabis model. The activation energy of MDS decreased from 28.716 to 11.390 kJ mol(-1) after disintegration. Consequently, the unit power requirement for thermal drying decreased remarkably from 706 to 281 W g(-1) H2O.

Two-phase anaerobic digestion of partially acidified sewage sludge: a pilot plant study for safe sludge disposal in developing countries.

PubMed

Passio, Luca; Rizzoa, Luigi; Fuchs, Stephan

2012-09-01

The unsafe disposal of wastewater and sludge in different areas of developing countries results in significant environmental pollution, particularly for groundwater, thus increasing the risk of waterborne diseases spreading. In this work, a two-phase anaerobic digestion process for post-treatment of partially acidified sewage sludge was investigated to evaluate its feasibility as a safe sludge disposal system. Pilot tests showed that an effective sludge stabilization can be achieved (total volatile solids content <65%, organic acid concentration <200 mg/L at flow rate = 50 L/d and hydraulic residence time = 18 d) as well as a relative low faecal coliform density (<1000 most probable number per g total solids), showing that land application of the sludge without restrictions is possible according to US Environmental Protection Agency criteria for safe sludge disposal. A biogas production as high as 390 L/d with a 60% methane content by volume was achieved, showing that energy production from biogas may be achieved as well.

Modelling the structure of sludge aggregates

PubMed Central

Smoczyński, Lech; Ratnaweera, Harsha; Kosobucka, Marta; Smoczyński, Michał; Kalinowski, Sławomir; Kvaal, Knut

2016-01-01

ABSTRACT The structure of sludge is closely associated with the process of wastewater treatment. Synthetic dyestuff wastewater and sewage were coagulated using the PAX and PIX methods, and electro-coagulated on aluminium electrodes. The processes of wastewater treatment were supported with an organic polymer. The images of surface structures of the investigated sludge were obtained using scanning electron microscopy (SEM). The software image analysis permitted obtaining plots log A vs. log P, wherein A is the surface area and P is the perimeter of the object, for individual objects comprised in the structure of the sludge. The resulting database confirmed the ‘self-similarity’ of the structural objects in the studied groups of sludge, which enabled calculating their fractal dimension and proposing models for these objects. A quantitative description of the sludge aggregates permitted proposing a mechanism of the processes responsible for their formation. In the paper, also, the impact of the structure of the investigated sludge on the process of sedimentation, and dehydration of the thickened sludge after sedimentation, was discussed. PMID:26549812

40 CFR 158.2280 - Environmental fate.

Code of Federal Regulations, 2013 CFR

2013-07-01

... biodegradability, porous pot, the biodegradation in activated sludge study as described in the “Simulation Tests to... applicant must choose either to: A. Conduct the biodegradation in activated sludge study as described in the... ready biodegradability study; or B. Conduct one of the following studies: The biodegradation in...

40 CFR 158.2280 - Environmental fate.

Code of Federal Regulations, 2014 CFR

2014-07-01

... biodegradability, porous pot, the biodegradation in activated sludge study as described in the “Simulation Tests to... applicant must choose either to: A. Conduct the biodegradation in activated sludge study as described in the... ready biodegradability study; or B. Conduct one of the following studies: The biodegradation in...

Biotransformation and sorption of trace organic compounds in biological nutrient removal treatment systems.

PubMed

Lakshminarasimman, Narasimman; Quiñones, Oscar; Vanderford, Brett J; Campo-Moreno, Pablo; Dickenson, Eric V; McAvoy, Drew C

2018-05-28

This study determined biotransformation rates (k bio ) and sorption-distribution coefficients (K d ) for a select group of trace organic compounds (TOrCs) in anaerobic, anoxic, and aerobic activated sludge collected from two different biological nutrient removal (BNR) treatment systems located in Nevada (NV) and Ohio (OH) in the United States (US). The NV and OH facilities operated at solids retention times (SRTs) of 8 and 23 days, respectively. Using microwave-assisted extraction, the biotransformation rates of the chosen TOrCs were measured in the total mixed liquor. Sulfamethoxazole, trimethoprim, and atenolol biotransformed in all three redox regimes irrespective of the activated sludge source. The biotransformation of N, N-diethyl-3-methylbenzamide (DEET), triclosan, and benzotriazole was observed in aerobic activated sludge from both treatment plants; however, anoxic biotransformation of these three compounds was seen only in anoxic activated sludge from NV. Carbamazepine was recalcitrant in all three redox regimes and both sources of activated sludge. Atenolol and DEET had greater biotransformation rates in activated sludge with a higher SRT (23 days), while trimethoprim had a higher biotransformation rate in activated sludge with a lower SRT (8 days). The remaining compounds did not show any dependence on SRT. Lyophilized, heat inactivated sludge solids were used to determine the sorption-distribution coefficients. Triclosan was the most sorptive compound followed by carbamazepine, sulfamethoxazole, DEET, and benzotriazole. The sorption-distribution coefficients were similar across redox conditions and sludge sources. The biotransformation rates and sorption-distribution coefficients determined in this study can be used to improve fate prediction of the target TOrCs in BNR treatment systems. Copyright © 2018. Published by Elsevier B.V.

Recycling of petroleum-contaminated sand.

PubMed

Taha, R; Ba-Omar, M; Pillay, A E; Roos, G; al-Hamdi, A

2001-08-01

The environmental impact of using petroleum-contaminated sand (PCS) as a substitute in asphalt paving mixtures was examined. An appreciable component of PCS is oily sludge, which is found as the dregs in oil storage tanks and is also produced as a result of oil spills on clean sand. The current method for the disposal of oily sludge is land farming. However, this method has not been successful as an oil content of < 1% w/w is required, and difficulty was encountered in reaching this target. The reuse of the sludge in asphalt paving mixtures was therefore considered as an alternative. Standard tests and environmental studies were conducted to establish the integrity of the materials containing the recycled sludge. These included physical and chemical characterization of the sludge itself, and an assessment of the mechanical properties of materials containing 0%, 5%, 22% and 50% oily sludge. The blended mixtures were subjected to special tests, such as Marshall testing and the determination of stability and flow properties. The experimental results indicated that mixtures containing up to 22% oily sludge could meet the necessary criteria for a specific asphalt concrete wearing course or bituminous base course. To maximize the assay from the recycled material, the environmental assessment was restricted to the 50% oily sludge mixture. Leachates associated with this particular mixture were assayed for total organic residue and certain hazardous metal contaminants. The results revealed that the organics were negligible, and the concentrations of the metals were not significant. Thus, no adverse environmental impact should be anticipated from the use of the recycled product. Our research showed that the disposal of oily sludge in asphalt paving mixtures could possibly yield considerable savings per tonne of asphalt concrete, and concurrently minimize any direct impact on the environment.

Characterization and biodegradability of sludge from a high rate A-stage contact tank and B-stage membrane bioreactor of a pilot-scale AB system treating municipal wastewaters.

PubMed

Trzcinski, Antoine Prandota; Ganda, Lily; Kunacheva, Chinagarn; Zhang, Dong Qing; Lin, Li Leonard; Tao, Guihe; Lee, Yingjie; Ng, Wun Jern

2016-10-01

In light of global warming mitigation efforts, increasing sludge disposal costs, and need for reduction in the carbon footprint of wastewater treatment plants, innovation in treatment technology has been tailored towards energy self-sufficiency. The AB process is a promising technology for achieving maximal energy recovery from wastewaters with minimum energy expenditure and therefore inherently reducing excess sludge production. Characterization of this novel sludge and its comparison with the more conventional B-stage sludge are necessary for a deeper understanding of AB treatment process design. This paper presents a case study of a pilot-scale AB system treating municipal wastewaters as well as a bio- (biochemical methane potential and adenosine tri-phosphate analysis) and physico-chemical properties (chemical oxygen demand, sludge volume index, dewaterability, calorific value, zeta potential and particle size distribution) comparison of the organic-rich A-stage against the B-stage activated sludge. Compared to the B-sludge, the A-sludge yielded 1.4 to 4.9 times more methane throughout the 62-week operation.

Selected heavy metals speciation in chemically stabilised sewage sludge

NASA Astrophysics Data System (ADS)

Wiśniowska, Ewa; Włodarczyk-Makuła, Marła

2017-11-01

Selected heavy metals (Pb, Ni, Cd) were analysed in soil, digested sewage sludge as well as in the sludge stabilised with CaO or Fenton's reagent. The dose of Fenton's reagent was as follows: Fe2+ = 1g.L-1, Fe2+/H2O2=1:100; stabilisation lasted for 2 h. Dose of CaO was equal to 1 g CaO.g d.m.-1 Total concentration of all metals in the digested sewage sludge was higher than in the soil. Chemical stabilisation of sludge with Fenton's reagent increased total metal content in the sludge as a result of total solids removal. Opposite effect was stated when the sludge was mixed with CaO. Also chemical fractions of heavy metals were identified (exchangeable, carbonate bound, iron oxides bound, organic and residual). The results indicate that stabilisation of the sludge with Fenton's reagent increased mobility of heavy metals compared to the digested sludge. Amendment of CaO increased percent share of examined metals in residual fraction, thus immobilised them and decreased their bioavailability.

Micropollutants in source separated wastewater streams and recovered resources of source separated sanitation.

PubMed

Butkovskyi, A; Leal, L Hernandez; Zeeman, G; Rijnaarts, H H M

2017-07-01

The quality of anaerobic sludge and struvite from black water treatment system, aerobic sludge from grey water treatment system and effluents of both systems was assessed for organic micropollutant content in order to ensure safety when reusing these products. Use of anaerobic black water sludge and struvite as soil amendments is recommended based on the low micropollutant content. Aerobic grey water sludge is recommended for disposal, because of the relatively high micropollutant concentrations, exceeding those in sewage sludge. Effluents of black and grey water treatment systems require post-treatment prior to reuse, because the measured micropollutant concentrations in the effluents are above ecotoxicological thresholds. Copyright © 2017 Elsevier Inc. All rights reserved.

Impact of mild alkali dosage on immobilized Exiguobacterium spp. mediated cost and energy efficient sludge disintegration.

PubMed

Rajesh Banu, J; Ushani, U; Rajkumar, M; Naresh Kumar, R; Parthiba Karthikeyan, O

2017-12-01

Approaches to (extracellular polymeric substance) EPS removal were studied with major aim to enhance the biodegradability and sludge solubilization. In this study, a novel approach of entrapment of bacterial strain was carried out to achieve long term activity of protease secreting bacteria Exiguobacterium sp. A mild treatment of potassium hydroxide (KOH) was applied to remove EPS which was followed by entrapment under the biological pretreatment. The efficiency of Exiguobacterium was predicted through dissolvable organic and suspended solids (SS) reduction. The maximum dissolvable organic matter released was 2300mg/L with the solubilization of 23% which was obtained for sludge without EPS (SWOE). For dissolvable organic release, SWOE showed higher final methane production of 232mL/g COD at the production rate of 16.2mL/g COD.d. The SWOE pretreatment was found to be cost effective and less energy intensive beneficial in terms of energy and cost (43.9KWh and -8.2USD) when compared to sludge with EPS (SWE) pretreatment (-177.6KWh and -91.23USD). Copyright © 2017 Elsevier Ltd. All rights reserved.

Utilization of lime-dried sludge for eco-cement clinker production: effects of different feeding points.

PubMed

Cao, Haihua; Liu, Wei; Xu, Jingcheng; Liu, Jia; Huang, Juwen; Huang, Xiangfeng; Li, Guangming

2018-02-01

Co-processing lime-dried sludge (LDS) in cement kilns is an appropriate technique to solve the problem of LDS disposal and promote the sustainable development for cement industry. However, there were limited studies that investigated the effects of feeding points on product quality and cement kiln emissions. In this study, simulated experiments were conducted by dividing the feeding points into high-temperature zones (HTZs) and raw mill (RM). Cement quality and major cement kiln emission characteristics were comprehensively investigated. The results showed that in terms of burnability, compressive strength and microstructure, the optimum co-processing amount of LDS were 9 wt% when feeding at RM, while 6% when feeding at HTZs. Meanwhile, the organic emissions of RM samples were mainly low environmental risk compounds of amides and nitrogenous heterocyclic compounds. Inorganic gaseous pollutions of NO X and SO 2 , respectively, were 8.11 mg/g DS and 12.89 mg/g DS, compared with 7.61 mg/g DS and 4.44 mg/g DS for HTZs. However, all the cement kiln emissions concentration were still much lower than standard requirements. Overall, RM had a bigger LDS co-processing capacity and higher, but acceptable, cement kiln emissions. Feeding LDS via RM could dispose larger amounts of sludge and provide more alternative materials for cement manufacturing.

Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization.

PubMed

Tiehm, A; Nickel, K; Zellhorn, M; Neis, U

2001-06-01

The pretreatment of waste activated sludge by ultrasonic disintegration was studied in order to improve the anaerobic sludge stabilization. The ultrasound frequency was varied within a range from 41 to 3217 kHz. The impact of different ultrasound intensities and treatment times was examined. Sludge disintegration was most significant at low frequencies. Low-frequency ultrasound creates large cavitation bubbles which upon collapse initiate powerful jet streams exerting strong shear forces in the liquid. The decreasing sludge disintegration efficiency observed at higher frequencies was attributed to smaller cavitation bubbles which do not allow the initiation of such strong shear forces. Short sonication times resulted in sludge floc deagglomeration without the destruction of bacteria cells. Longer sonication brought about the break-up of cell walls, the sludge solids were distintegrated and dissolved organic compounds were released. The anaerobic digestion of waste activated sludge following ultrasonic pretreatment causing microbial cell lysis was significantly improved. There was an increase in the volatile solids degradation as well as an increase in the biogas production. The increase in digestion efficiency was proportional to the degree of sludge disintegration. To a lesser degree the deagglomeration of sludge flocs also augmented the anaerobic volatile solids degradation.

An innovative sewage sludge reduction by using a combined mesophilic anaerobic and thermophilic aerobic process with thermal-alkaline treatment and sludge recirculation.

PubMed

Cho, Hyun Uk; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

2013-11-15

Lab-scale High Efficiency Digestion (HED) systems containing a Mesophilic Anaerobic Reactor (MAR), Thermophilic Aerobic Reactor (TAR), liquid/solid separation unit, and thermal-alkaline treatment were developed to evaluate the efficiencies of sludge reduction and methane production. The HED process was divided into three phases to examine the influence of sludge pretreatment and pretreated sludge recirculation using TCOD and VSS reduction, COD solubilization, and methane production. The VSS removal with a solid/liquid separation unit, sludge recirculation, and thermal-alkaline treatment drastically increased up to 95% compared to the feed concentration. In addition, the results of COD solubilization and VSS/TSS showed that the solubilization of cells and organic matters by the thermal-alkaline treatment was highly increased, which was also consistent with the SEM images. In particular, the methane production rate increased 24-fold when the feed sludge and recirculated sludge were pretreated together. Collectively, the HED experiments performed with sludge recirculation and thermal-alkaline treatment demonstrated that the HED systems can be successfully employed for highly efficient sewage sludge reduction and methane gas production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Acceleration of organic removal and electricity generation from dewatered oily sludge in a bioelectrochemical system by rhamnolipid addition.

PubMed

Zhang, Yunshu; Zhao, Qingliang; Jiang, Junqiu; Wang, Kun; Wei, Liangliang; Ding, Jing; Yu, Hang

2017-11-01

Conversion of biomass energy of dewatered oily sludge to electricity is the rate-limiting process in bioelectrochemical system (BES). In this study, 2mgg -1 rhamnolipids were added to dewatered oily sludge, resulting in a significant enhancement in maximum power density from 3.84±0.37 to 8.63±0.81Wm -3 , together with an increase in total organic carbon (TOC) and total petroleum hydrocarbon (TPH) removal from 24.52±4.30 to 36.15±2.79mgg -1 and 29.51±3.30 to 39.80±2.47mgg -1 , respectively. Rhamnolipids can also enhance the solubilization and promote the hydrolysis of dewatered oily sludge with increases in SOCD from 14.93±2.44 to 18.40±0.08mgg -1 and VFAs from 1.02±0.07 to 1.39±0.12mgg -1 . Furthermore, bacteria related to substrate degradation were predominant in dewatered oily sludge, and bacteria related to the sulfate/sulfide cycle were significantly enriched by rhamnolipid addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Algal sludge from Taihu Lake can be utilized to create novel PGPR-containing bio-organic fertilizers.

PubMed

Zhang, Miao; Li, Rong; Cao, Liangliang; Shi, Juanjuan; Liu, Hongjun; Huang, Yan; Shen, Qirong

2014-01-01

Large amounts of refloated algal sludge from Taihu Lake result in secondary environmental pollution due to annual refloatation. This study investigated the possibility to produce bio-organic fertilizer (BIO) using algal sludge as a solid-state fermentation (SSF) medium. Results showed that addition of algal sludge contributed to efficient SFF by a plant growth-promoting rhizobacteria (PGPR) strain SQR9 and improved the nutrient contents in the novel BIO. The optimum water content and initial inoculation size were 45% and 5%, respectively. After 6 days of SSF, the biomass of strain SQR9 was increased to a cell density of more than 5 × 10(7) CFU g(-1). Microcystins were rapidly degraded, and a high germination index value was observed. Plant growth experiments showed that the produced BIO efficiently promoted plant growth. Additional testing showed that the novel SSF process was also suitable for other PGPR strains. This study provides a novel way of high-value utilization of algal sludge from Taihu Lake by producing low-cost but high-quality BIOs. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluation of different types of anaerobic seed sludge for the high rate anaerobic digestion of pig slurry in UASB reactors.

PubMed

Rico, Carlos; Montes, Jesús A; Rico, José Luis

2017-08-01

Three different types of anaerobic sludge (granular, thickened digestate and anaerobic sewage) were evaluated as seed inoculum sources for the high rate anaerobic digestion of pig slurry in UASB reactors. Granular sludge performance was optimal, allowing a high efficiency process yielding a volumetric methane production rate of 4.1LCH 4 L -1 d -1 at 1.5days HRT (0.248LCH 4 g -1 COD) at an organic loading rate of 16.4gCODL -1 d -1 . The thickened digestate sludge experimented flotation problems, thus resulting inappropriate for the UASB process. The anaerobic sewage sludge reactor experimented biomass wash-out, but allowed high process efficiency operation at 3days HRT, yielding a volumetric methane production rate of 1.7LCH 4 L -1 d -1 (0.236LCH 4 g -1 COD) at an organic loading rate of 7.2gCODL -1 d -1 . To guarantee the success of the UASB process, the settleable solids of the slurry must be previously removed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dewatering and granulation of sewage sludge by biophysical drying and thermo-degradation performance of prepared sludge particles during succedent fast pyrolysis.

PubMed

Han, Rong; Liu, Jinwen; Zhang, Yuancheng; Fan, Xiaoqian; Lu, Wenjing; Wang, Hongtao

2012-03-01

A novel two-step technology, fast biophysical drying (BPD) coupling with fast pyrolysis (FP), was investigated for moisture removal and energy recovery from sewage sludge. For BPD, combined operations of extreme thermophilic amendment (with accelerated increasing and controllable maintenance of substrate temperature) and enhanced convective evaporation were conducted, both beneficial for moisture removal (moisture content reaching 23.1% for 7d) and organic preservation. Biophysical-dried sludge (BPDS) was characterized by homogeneous fine-particle morphology and well-developed porous microstructure. The synthesized BPDS particle preserved most organic components (92% volatile matters and 79% HHV of traditional thermal-dried sludge [TTDS]) attributable to the inhibitory effect of BPD adjustment, presenting considerable capacity for subsequent residue-derived energy. For FP, the distribution of products from BPDS pyrolysis indicated that syngas and char yields were higher than those of TTDS. The syngas from BPDS is a type of hydrogen-rich gas composed of 42.6 vol.% H(2) at 900°C. Copyright © 2011 Elsevier Ltd. All rights reserved.

Fluorescence-based monitoring of tracer and substrate distribution in an UASB reactor.

PubMed

Lou, S J; Tartakovsky, B; Zeng, Y; Wu, P; Guiot, S R

2006-11-01

In this work, rhodamine-related fluorescence was measured on-line at four reactor heights in order to study hydrodynamics within an upflow anaerobic sludge bed reactor. A linear dependence of the dispersion coefficient (D) on the upflow velocity was observed, while the influence of the organic loading rate (OLR) was insignificant. Furthermore, the Bodenstein number of the reactor loaded with granulated sludge was found to be position-dependent with the largest values measured at the bottom of the sludge bed. This trend was not observed in the reactor without sludge. Chemical oxygen demand (COD) and volatile fatty acid (VFA) concentrations were measured at the same reactor heights as in rhodamine tests using conventional off-line analytical methods and on-line multiwavelength fluorometry. Significant spatial COD and VFA gradients were observed at organic loading rates above 6g COD l(R)(-1)d(-1) and linear upflow velocities below 0.8m h(-1).

Recycle of valuable products from oily cold rolling mill sludge

NASA Astrophysics Data System (ADS)

Liu, Bo; Zhang, Shen-gen; Tian, Jian-jun; Pan, De-an; Liu, Yang; Volinsky, Alex A.

2013-10-01

Oily cold rolling mill (CRM) sludge contains lots of iron and alloying elements along with plenty of hazardous organic components, which makes it as an attractive secondary source and an environmental contaminant at the same time. The compound methods of "vacuum distillation + oxidizing roasting" and "vacuum distillation + hydrogen reduction" were employed for the recycle of oily cold rolling mill sludge. First, the sludge was dynamically vacuum distilled in a rotating furnace at 50 r/min and 600°C for 3 h, which removed almost hazardous organic components, obtaining 89.2wt% ferrous resultant. Then, high purity ferric oxide powders (99.2wt%) and reduced iron powders (98.9wt%) were obtained when the distillation residues were oxidized and reduced, respectively. The distillation oil can be used for fuel or chemical feedstock, and the distillation gases can be collected and reused as a fuel.

Application of dielectric constant measurement in microwave sludge disintegration and wastewater purification processes.

PubMed

Kovács, Petra Veszelovszki; Lemmer, Balázs; Keszthelyi-Szabó, Gábor; Hodúr, Cecilia; Beszédes, Sándor

2018-05-01

It has been numerously verified that microwave radiation could be advantageous as a pre-treatment for enhanced disintegration of sludge. Very few data related to the dielectric parameters of wastewater of different origins are available; therefore, the objective of our work was to measure the dielectric constant of municipal and meat industrial wastewater during a continuous flow operating microwave process. Determination of the dielectric constant and its change during wastewater and sludge processing make it possible to decide on the applicability of dielectric measurements for detecting the organic matter removal efficiency of wastewater purification process or disintegration degree of sludge. With the measurement of dielectric constant as a function of temperature, total solids (TS) content and microwave specific process parameters regression models were developed. Our results verified that in the case of municipal wastewater sludge, the TS content has a significant effect on the dielectric constant and disintegration degree (DD), as does the temperature. The dielectric constant has a decreasing tendency with increasing temperature for wastewater sludge of low TS content, but an adverse effect was found for samples with high TS and organic matter contents. DD of meat processing wastewater sludge was influenced significantly by the volumetric flow rate and power level, as process parameters of continuously flow microwave pre-treatments. It can be concluded that the disintegration process of food industry sludge can be detected by dielectric constant measurements. From technical purposes the applicability of dielectric measurements was tested in the purification process of municipal wastewater, as well. Determination of dielectric behaviour was a sensitive method to detect the purification degree of municipal wastewater.

Characterization of antibiotic resistance genes in representative organic solid wastes: Food waste-recycling wastewater, manure, and sewage sludge.

PubMed

Lee, Jangwoo; Shin, Seung Gu; Jang, Hyun Min; Kim, Young Beom; Lee, Joonyeob; Kim, Young Mo

2017-02-01

In this research, the distribution of antibiotic resistance genes (ARGs) was characterized in representative organic solid waste (OSW) in Korea: food waste-recycling wastewater (FRW), manure, and sewage sludge. The amounts of total ARG (gene copies/16S rRNA gene copies) was greatest in manure followed by sewage sludge and FRW. Interestingly, there were significantly different patterns in the diversity and mechanisms of ARGs. For example, a significant proportion of ARGs were tetracycline resistant genes in all the OSW (40.4-78.2%). β-lactam antibiotics resistant genes were higher in the FRW samples than in other types of OSW but sulfonamides resistant genes represented the greatest proportion in sludge. Regarding the characteristics of antibiotic resistance mechanisms, there was a relatively higher proportion of the ribosomal protection mechanism to tetracycline observed in the FRW and manure samples. However, tetracycline resistant genes with direct interaction were relatively higher in the sewage sludge samples. sul1 was the dominant subtype in all the OSW types and detection of ermB was observed although there was no ermC detected in sewage sludge. There were significant correlations between the occurrences of ARG subtypes: tetB and tetG in all OSW (P<0.01); tetE and tetQ only in sludge (P<0.01). The Class 1 integron-integrase gene (intI1) was significantly correlated with total ARGs only in manure and sludge (P<0.05), revealing potential horizontal gene transfer in these OSW. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of vermicompost characteristics produced from sewage sludge of wood and paper industry and household solid wastes.

PubMed

Amouei, A I; Yousefi, Z; Khosravi, T

2017-01-01

The aim of this study was to determine the potential of produced compost from the sludge of wastewater treatment plant using earthworms and compare it with the vermicompost produced from household solid waste. In the current study, three treatments with the same conditions in terms of organic wastes type were prepared to produce vermicompost from household solid waste and sewage sludges using earthworms. The standard methods were used to determine the physical and chemical parameters in the different produced vermicomposts. The mean of C/N in the household solid waste, raw biological and chemical sludges was 32, 22.5, and 26.5, respectively. These levels were 16.5, 14.5, and 15 in the vermicomposts. The mean of nitrogen and phosphorus percentages in the vermicompost of solid waste, biological and chemical sludges was 2.2%, 2.6%, 2.3% and 0.72%, 0.54%, and 0.56%, respectively. The mean percentages of organic matters in the initial substrates and vermicomposts of solid waste, biological and chemical sludges were 97.2%, 90%, 80.5% and 65.8%, 67.8% and 63% respectively. The concentrations of heavy metals decreased in all vermicomposts. The EC levels in solid waste, biological and chemical sludges were 1459, 1041, and 1487 μs/cm, respectively. These levels were 544, 385 and 635 μs/cm in the produced compost. Eisenia fetida can convert household solid waste, and biological and chemical sludges produced from wastewater treatment plant into a high-quality and acceptable compost.

Effect of energy grass on methane production and heavy metal fractionation during anaerobic digestion of sewage sludge.

PubMed

Zhang, Min; Yang, Changming; Jing, Yachao; Li, Jianhua

2016-12-01

Anaerobic digestion (AD) is one of the most widely used processes to stabilize waste sewage sludge and produce biogas as renewable energy. The relatively low organic matter content and high heavy metal concentrations in sewage sludge have severely restricted the application and development of AD technology in China. In this study, the effect of energy grass (Pennisetum alopecuroides) addition on methane production and heavy metal fractionation during the AD of sewage sludge was evaluated. Methane production was enhanced by 11.2% by the addition of P. alopecuroides. The addition of P. alopecuroides significantly reduced the percentages of the water-soluble and exchangeable fractions of the target heavy metals in the sewage sludge after AD, and the dominant species were concentrated in Fe-Mn oxide-bound and organic- and sulfide-bound fractions of the digested sludge. The addition of P. alopecuroides at a dosage of 0.3kg significantly (P<0.05) decreased the mobility factors (MFs) of the target heavy metals after AD. In particular, the MFs of Cr and Ni were 61% and 32% lower, respectively, relative to the control. The increase in the added dose did not necessarily lead to further decreases in the MFs of the heavy metals. These results demonstrate that an appropriate addition of energy grass could enhance AD, decrease the mobility of heavy metals and promote heavy metal stabilization in sewage sludge during AD, which is beneficial for the subsequent land application of sewage sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

Is anaerobic digestion effective for the removal of organic micropollutants and biological activities from sewage sludge?

PubMed

Gonzalez-Gil, L; Papa, M; Feretti, D; Ceretti, E; Mazzoleni, G; Steimberg, N; Pedrazzani, R; Bertanza, G; Lema, J M; Carballa, M

2016-10-01

The occurrence of emerging organic micropollutants (OMPs) in sewage sludge has been widely reported; nevertheless, their fate during sludge treatment remains unclear. The objective of this work was to study the fate of OMPs during mesophilic and thermophilic anaerobic digestion (AD), the most common processes used for sludge stabilization, by using raw sewage sludge without spiking OMPs. Moreover, the results of analytical chemistry were complemented with biological assays in order to verify the possible adverse effects (estrogenic and genotoxic) on the environment and human health in view of an agricultural (re)use of digested sludge. Musk fragrances (AHTN, HHCB), ibuprofen (IBP) and triclosan (TCS) were the most abundant compounds detected in sewage sludge. In general, the efficiency of the AD process was not dependent on operational parameters but compound-specific: some OMPs were highly biotransformed (e.g. sulfamethoxazole and naproxen), while others were only slightly affected (e.g. IBP and TCS) or even unaltered (e.g. AHTN and HHCB). The MCF-7 assay evidenced that estrogenicity removal was driven by temperature. The Ames test did not show point mutation in Salmonella typhimurium while the Comet test exhibited a genotoxic effect on human leukocytes attenuated by AD. This study highlights the importance of combining chemical analysis and biological activities in order to establish appropriate operational strategies for a safer disposal of sewage sludge. Actually, it was demonstrated that temperature has an insignificant effect on the disappearance of the parent compounds while it is crucial to decrease estrogenicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of plant-wide WWTP control strategies including the effects of filamentous bulking sludge.

PubMed

Flores-Alsina, Xavier; Comas, Joaquim; Rodríguez Roda, Ignasi; Poch, Manel; Gernaey, Krist V; Jeppsson, Ulf

2009-01-01

The main objective of this paper is to evaluate the effect of filamentous bulking sludge on the predicted performance of simulated plant-wide WWTP control strategies. First, as a reference case, several control strategies are implemented, simulated and evaluated using the IWA Benchmark Simulation Model No. 2 (BSM2). In a second series of simulations the parameters of the secondary settler model in the BSM2 are automatically changed on the basis of an on-line calculated risk of filamentous bulking, in order to mimic the effect of growth of filamentous bacteria in the plant. The results are presented using multivariate analysis. Including the effects of filamentous bulking in the simulation model gives a-more realistic-deterioration of the plant performance during periods when the conditions for development of filamentous bulking sludge are favourable: compared to the reference case where bulking effects are not considered. Thus, there is a decrease of the overall settling velocity, an accumulation of the total suspended solids (TSS) in the middle layers of the settler with a consequent reduction of their degree of compaction in the bottom. As a consequence there is a lower TSS concentration in both return and waste flow, less biomass in the bioreactors and a reduction of the TSS removal efficiency. The control alternatives using a TSS controller substantially increase the food to microorganisms (F/M) ratio in the bioreactor, thereby reducing both risk and effects of bulking sludge. The effects of ammonium (NH(4)(+)), nitrate (NO(3)(-)) and reject water control strategies are rather poor when it comes to handling solids separation problems.

Highly efficient secondary dewatering of dewatered sewage sludge using low boiling point solvents.

PubMed

He, Chao; Chena, Chia-Lung; Xu, Zhirong; Wang, Jing-Yuan

2014-01-01

Secondary dewatering of dewatered sludge is imperative to make conventional drying and incineration of sludge more economically feasible. In this study, a secondary dewatering of dewatered sludge with selected solvents (i.e. acetone and ethanol) followed by vacuum filtration and nature drying was investigated to achieve in-depth dewatering. After the entire secondary dewatering process, the sludge was shown to be odourless and the organic matter content was greatly retained. Increased mean particle size of sludge after solvent contact improved solid-liquid separation. With an acetone/sludge ratio of 3:1 (mL:g) in solvent contact and subsequent nature drying at ambient temperature after 24 h, the moisture content of sludge can be reduced to a level less than 20%. It is found that the polysaccharides were mainly precipitated by acetone, whereas the release ratios of protein and DNA were increased significantly as the added acetone volumes were elevated. During nature drying, accumulated evaporation rates of the sludge after solvent contact were 5-6 times higher than original dewatered sludge. Furthermore, sludge after acetone contact had better nature drying performance than ethanol. The two-stage dewatering involves solvent contact dewatering and solvent enhanced evaporation dewatering. Through selecting an appropriate solvent/sludge ratio as well as economical solvents and minimizing the solvent loss in a closed-pilot system, this dewatering process can be competitive in industrial applications. Therefore, this solvent-aided secondary dewatering is an energy-saving technology for effective in-depth dewatering of dewatered sludge and subsequent sludge utilization.

Gasification of yeast industry treatment plant sludge using downdraft Gasifier.

PubMed

Ayol, Azize; Tezer, Ozgun; Gurgen, Alim

2018-01-01

Sludges produced in biological wastewater treatment plants have rich organic materials in their characteristics. Recent research studies have focused on the energy recovery from sludge due to its high organic content. The gasification process is a thermal conversion technology transforming the chemical energy contained in a solid fuel into thermal energy and electricity. The produced syngas as a mixture of CO, CH 4 , H 2 and other gases can be used to generate electrical energy. The gasification of yeast industry sludge has been experimentally evaluated in a pilot scale downdraft-type gasifier as a route towards the energy recovery. The gasifier has 20 kg biomass/h fuel capacity. During gasification, the temperature achieved was more than 1,000°C in the gasifier, and then the syngas was transferred to the gas engine to yield the electricity. A load was connected to the grid box and approximately 1 kWh electrical power generation for 1 kg dry sludge was determined. The characteristics of residuals - ash, glassy material - were also analyzed. It was found that most of the heavy metals were fixed in the glassy material. Experimental results showed that the yeast industry sludge was an appropriate material for gasification studies and remarkable energy recovery was obtained in terms of power production by using syngas.

Survey of the Anaerobic Biodegradation Potential of Organic Chemicals in Digesting Sludge

PubMed Central

Battersby, Nigel S.; Wilson, Valerie

1989-01-01

The degradation potential of 77 organic chemicals under methanogenic conditions was examined with an anaerobic digesting sludge from the United Kingdom. Degradation was assessed in terms of net total gas (CH4 plus CO2) produced, expressed as a percentage of the theoretical production (ThGP). The compounds tested were selected from various chemical groups and included substituted phenols and benzoates, pesticides, phthalic acid esters, homocyclic and heterocyclic ring compounds, glycols, and monosubstituted benzenes. The results obtained were in good agreement with published surveys of biodegradability in U.S. digesting sludges and other methanogenic environments. In general, the presence of chloro or nitro groups inhibited anaerobic gas production, while carboxyl and hydroxyl groups facilitated biodegradation. The relationship between substituent position and susceptibility to methanogenic degradation was compound dependent. The following chemicals were completely degraded (≥80% ThGP) at a concentration of 50 mg of carbon per liter: phenol, 2-aminophenol, 4-cresol, catechol, sodium benzoate, 4-aminobenzoic acid, 3-chlorobenzoic acid, phthalic acid, ethylene glycol, diethylene glycol, triethylene glycol, sodium stearate, and quinoline. 3-Cresol, 4-chlorobenzoic acid, dimethyl phthalate, and pyridine were partially degraded. Although the remaining chemicals tested were either persistent or toxic, their behavior may differ at more environmentally realistic chemical-to-biomass ratios. Our findings suggest that biodegradability assessments made with sludge from one source can be extrapolated to sludge from another source with a reasonable degree of confidence and should help in predicting the fate of an organic chemical during the anaerobic digestion of sewage sludge. PMID:16347851

pH-dependent biotransformation of ionizable organic micropollutants in activated sludge.

PubMed

Gulde, Rebekka; Helbling, Damian E; Scheidegger, Andreas; Fenner, Kathrin

2014-12-02

Removal of micropollutants (MPs) during activated sludge treatment can mainly be attributed to biotransformation and sorption to sludge flocs, whereby the latter process is known to be of minor importance for polar organic micropollutants. In this work, we investigated the influence of pH on the biotransformation of MPs with cationic-neutral speciation in an activated sludge microbial community. We performed batch biotransformation, sorption control, and abiotic control experiments for 15 MPs with cationic-neutral speciation, one control MP with neutral-anionic speciation, and two neutral MPs at pHs 6, 7, and 8. Biotransformation rate constants corrected for sorption and abiotic processes were estimated from measured concentration time series with Bayesian inference. We found that biotransformation is pH-dependent and correlates qualitatively with the neutral fraction of the ionizable MPs. However, a simple speciation model based on the assumption that only the neutral species is efficiently taken up and biotransformed by the cells tends to overpredict the effect of speciation. Therefore, additional mechanisms such as uptake of the ionic species and other more complex attenutation mechanisms are discussed. Finally, we observed that the sorption coefficients derived from our control experiments were small and showed no notable pH-dependence. From this we conclude that pH-dependent removal of polar, ionizable organic MPs in activated sludge systems is less likely an effect of pH-dependent sorption but rather of pH-dependent biotransformation. The latter has the potential to cause marked differences in the removal of polar, ionizable MPs at different operational pHs during activated sludge treatment.

Co-pyrolysis of sewage sludge and manure.

PubMed

Ruiz-Gómez, Nadia; Quispe, Violeta; Ábrego, Javier; Atienza-Martínez, María; Murillo, María Benita; Gea, Gloria

2017-01-01

The management and valorization of residual organic matter, such as sewage sludge and manure, is gaining interest because of the increasing volume of these residues, their localized generation and the related problems. The anaerobic digestion of mixtures of sewage sludge and manure could be performed due to the similarities between both residues. The purpose of this study is to evaluate the feasibility of the co-pyrolysis of sewage sludge (SS) and digested manure (DM) as a potential management technology for these residues. Pyrolysis of a sewage sludge/manure blend (50:50%) was performed at 525°C in a stirred batch reactor under N 2 atmosphere. The product yields and some characteristics of the product were analyzed and compared to the results obtained in the pyrolysis of pure residues. Potential synergetic and antagonist effects during the co-pyrolysis process were evaluated. Although sewage sludge and manure seem similar in nature, there are differences in their pyrolysis product properties and distribution due to their distinct ash and organic matter composition. For the co-pyrolysis of SS and DM, the product yields did not show noticeable synergistic effects with the exception of the yields of organic compounds, being slightly higher than the predicted average, and the H 2 yield, being lower than expected. Co-pyrolysis of SS and DM could be a feasible management alternative for these residues in locations where both residues are generated, since the benefits and the drawbacks of the co-pyrolysis are similar to those of the pyrolysis of each residue. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhancement of organic matter degradation and methane gas production of anaerobic granular sludge by degasification of dissolved hydrogen gas.

PubMed

Satoh, Hisashi; Bandara, Wasala M K R T W; Sasakawa, Manabu; Nakahara, Yoshihito; Takahashi, Masahiro; Okabe, Satoshi

2017-11-01

A hollow fiber degassing membrane (DM) was applied to enhance organic matter degradation and methane gas production of anaerobic granular sludge process by reducing the dissolved hydrogen gas (D-H 2 ) concentration in the liquid phase. DM was installed in the bench-scale anaerobic granular sludge reactors and D-H 2 was removed through DM using a vacuum pump. Degasification improved the organic matter degradation efficiency to 79% while the efficiency was 62% without degasification at 12,000mgL -1 of the influent T-COD concentration. Measurement of D-H 2 concentrations in the liquid phase confirmed that D-H 2 was removed by degasification. Furthermore, the effect of acetate concentrations on the organic matter degradation efficiency was investigated. At acetate concentrations above 3gL -1 , organic matter degradation deteriorated. Degasification enhanced the propionate and acetate degradation. These results suggest that degasification reduced D-H 2 concentration and volatile fatty acids concentrations, prevented pH drop, and subsequent enhanced organic matter degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Effect of simulated inorganic anion leaching solution of electroplating sludge on the bioactivity of Acidithiobacillus ferrooxidans].

PubMed

Chen, Yan; Huang, Fang; Xie, Xin-Yuan

2014-04-01

An Acidithiobacillus ferrooxidans strain WZ-1 (GenBank sequence number: JQ968461) was used as the research object. The effects of Cl-, NO3-, F- and 4 kinds of simulated inorganic anions leaching solutions of electroplating sludge on the bioactivity of Fe2+ oxidation and apparent respiratory rate of WZ-1 were investigated. The results showed that Cl-, NO3(-)- didn't have any influence on the bioactivity of WZ-1 at concentrations of 5.0 g x L(-1), 1.0 g x L(-1), respectively. WZ-1 showed tolerance to high levels of Cl- and NO3- (about 10.0 g x L(-1), 5.0 g x L(-1), respectively), but it had lower tolerance to F- (25 mg x L(-1)). Different kinds of simulated inorganic anions leaching solutions of electroplating sludge had significant differences in terms of their effects on bioactivity of WZ-1 with a sequence of Cl-/NO3(-)/F(-) > or = NO3(-)/F(-) > Cl-/F(-) > Cl(-)/NO3(-).

Simulation of water removal process and optimization of aeration strategy in sewage sludge composting.

PubMed

Zhou, Hai-Bin; Chen, Tong-Bin; Gao, Ding; Zheng, Guo-Di; Chen, Jun; Pan, Tian-Hao; Liu, Hong-Tao; Gu, Run-Yao

2014-11-01

Reducing moisture in sewage sludge is one of the main goals of sewage sludge composting and biodrying. A mathematical model was used to simulate the performance of water removal under different aeration strategies. Additionally, the correlations between temperature, moisture content (MC), volatile solids (VS), oxygen content (OC), and ambient air temperature and aeration strategies were predicted. The mathematical model was verified based on coefficients of correlation between the measured and predicted results of over 0.80 for OC, MC, and VS, and 0.72 for temperature. The results of the simulation showed that water reduction was enhanced when the average aeration rate (AR) increased to 15.37 m(3) min(-1) (6/34 min/min, AR: 102.46 m(3) min(-1)), above which no further increase was observed. Furthermore, more water was removed under a higher on/off time of 7/33 (min/min, AR: 87.34 m(3) min(-1)), and when ambient air temperature was higher. Copyright © 2014 Elsevier Ltd. All rights reserved.

DESIGN MANUAL: DEWATERING MUNICIPAL WASTEWATER SLUDGES

EPA Science Inventory

This manual discusses the many factors involved in selecting and designing dewatering equipment for organic sludges produced during primary and secondary municipal wastewater treatment. ive-step approach is outlined for the selection and design of the dewatering equipment for eit...

Dewaterability of five sewage sludges in Guangzhou conditioned with Fenton's reagent/lime and pilot-scale experiments using ultrahigh pressure filtration system.

PubMed

Liang, Jialin; Huang, Shaosong; Dai, Yongkang; Li, Lei; Sun, Shuiyu

2015-11-01

Sludge conditioning with Fenton's reagent and lime is a valid method for sludge dewatering. This study investigated the influence of different organic matter content sludge on sludge dewatering and discussed the main mechanism of sludge conditioning by combined Fenton's reagent and lime. The results indicated that the specific resistance to filterability (SRF) of sludge was reduced efficiently by approximately 90%, when conditioned with Fenton's reagent and lime. Through single factor experiments, the optimal conditioning combinations were found. In addition, the relationship between VSS% and consumption of the reagents was detected. Furthermore, it was also demonstrated that the SRF and filtrate TOC values had a significant correlation with VSS% of sludge (including raw and conditioned). The main mechanism of sludge dewatering was also investigated. Firstly, it revealed that the dewaterability of sludge was closely correlated to extracellular polymeric substances (EPS) and bound water contents. Secondly, the results of scanning electron microscopy (SEM) stated that sludge particles were to be smaller and thinner after conditioning. And this structure could easily form outflow channels for releasing free water. Additionally, with the ultrahigh pressure filtration system, the water content of sludge cake conditioned with Fenton's reagent and lime could be reduced to below 50%. Moreover, the economic assessment shows that Fenton's reagent and lime combined with ultrahigh pressure filtration system can be an economical and viable technology for sewage sludge dewatering. Finally, three types of sludge were classified: (1) Fast to dewater; (2) Moderately fast to dewater; (3) Slow to dewater sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

Two strategies for phosphorus removal from reject water of municipal wastewater treatment plant using alum sludge.

PubMed

Yang, Y; Zhao, Y Q; Babatunde, A O; Kearney, P

2009-01-01

In view of the well recognized need of reject water treatment in MWWTP (municipal wastewater treatment plant), this paper outlines two strategies for P removal from reject water using alum sludge, which is produced as by-product in drinking water treatment plant when aluminium sulphate is used for flocculating raw waters. One strategy is the use of the alum sludge in liquid form for co-conditioning and dewatering with the anaerobically digested activated sludge in MWWTP. The other strategy involves the use of the dewatered alum sludge cakes in a fixed bed for P immobilization from the reject water that refers to the mixture of the supernatant of the sludge thickening process and the supernatant of the anaerobically digested sludge. Experimental trials have demonstrated that the alum sludge can efficiently reduce P level in reject water. The co-conditioning strategy could reduce P from 597-675 mg P/L to 0.14-3.20 mg P/L in the supernatant of the sewage sludge while the organic polymer dosage for the conditioning of the mixed sludges would also be significantly reduced. The second strategy of reject water filtration with alum sludge bed has shown a good performance of P reduction. The alum sludge has P-adsorption capacity of 31 mg-P/g-sludge, which was tested under filtration velocity of 1.0 m/h. The two strategies highlight the beneficial utilization of alum sludge in wastewater treatment process in MWWTP, thus converting the alum sludge as a useful material, rather than a waste for landfill.

Impact of sludge treatments on the extractability and fate of acetyl sulfamethoxazole residues in amended soils.

PubMed

Geng, Chunnu; Bergheaud, Valérie; Garnier, Patricia; Zhu, Yong-Guan; Haudin, Claire-Sophie

2018-03-01

Sludge recycled in agriculture may bring antibiotics into cropped soils. The nature, total amount, and availability of the antibiotics in soil partly depend on the sludge treatments. Our paper compares the fate of N-acetyl sulfamethoxazole (AC-SMX) residues between soils incubated with the same sludge but submitted to different processes before being added in soil. The fate of 14 C-AC-SMX residues was studied in mixtures of soil and sludges at different treatment levels: 1) activated and 2) centrifuged sludges, both enriched with 14 C-AC-SMX, and 3) limed and 4) heat-dried sludges obtained by treating the previously contaminated centrifuged sludge. The evolution of the extractability of 14 C residues (CaCl 2 , methanol) and their mineralization were followed during 119 days. More than 80% of the initial 14 C-activity was no longer extractable after 14 days, except in soil with limed sludge. Liming and drying the centrifuged sludge decreased the mineralized 14 C fraction from 5.7-6.4% to 1.2-1.8% and consequently, the corresponding soils contained more 14 C residues after 119 days. Although 14 C residues were more CaCl 2 -extractable in soil with limed sludge, they seemed to be poorly bioavailable for biodegradation. For all solid sludges, the mineralization rate of 14 C-AC-SMX residues was strongly correlated to that of sludge organic carbon, with a coefficient three times lower for the limed and dried sludges than for the centrifuged sludge after 14 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

The thin-layer drying characteristics of sewage sludge by the appropriate foaming pretreatment.

PubMed

Wang, Hui-Ling; Yang, Zhao-Hui; Huang, Jing; Wang, Li-Ke; Gou, Cheng-Liu; Yan, Jing-Wu; Yang, Jian

2014-01-01

As dewatered sludge is highly viscous and sticky, the combination of foaming pretreatment and drying process seems to be an alternative method to improve the drying performance of dewatered sludge. In this study, CaO addition followed by mechanical whipping was employed for foaming the dewatered sludge. It was found that the foams were stable and the diameters of bubbles mainly ranged from 0.1 to 0.3 mm. The drying experiments were carried out in a drying oven in the convective mode. The results indicated that foamed sludge at 0.70 g/cm(3) had the best drying performance at each level of temperature, which could save 35-45% drying time to reach 20% moisture content compared with the non-foamed sludge. The drying rate of foamed sludge at 0.70 g/cm(3) was improved with the increasing of drying temperature. The impact of sample thickness on drying rate was not obvious when the sample thickness increased from 2 to 8 mm. Different mathematical models were used for the simulation of foamed sludge drying curves. The Wang and Singh model represented the drying characteristics better than other models with coefficient of determination values over 0.99.

Biomass characterization by dielectric monitoring of viability and oxygen uptake rate measurements in a novel membrane bioreactor.

PubMed

Shariati, Farshid Pajoum; Heran, Marc; Sarrafzadeh, Mohammad Hossein; Mehrnia, Mohammad Reza; Sarzana, Gabriele; Ghommidh, Charles; Grasmick, Alain

2013-07-01

The application of permittivity and oxygen uptake rate (OUR) as biological process control parameters in a wastewater treatment system was evaluated. Experiments were carried out in a novel airlift oxidation ditch membrane bioreactor under different organic loading rates (OLR). Permittivity as representative of activated sludge viability was measured by a capacitive on-line sensor. OUR was also measured as a representative for respirometric activity. Results showed that the biomass concentration increases with OLR and all biomass related measurements and simulators such as MLSS, permittivity, OUR, ASM1 and ASM3 almost follow the same increasing trends. The viability of biomass decreased when the OLR was reduced from 5 to 4 kg COD m(-3)d(-1). During decreasing of OLR, biomass related parameters generally decreased but not in a similar manner. Also, protein concentration in the system during OLR decreasing changed inversely with the activated sludge viability. Copyright © 2013 Elsevier Ltd. All rights reserved.

Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge.

PubMed

Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M

2015-01-01

The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge.

Effect of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions.

PubMed

Diak, James; Örmeci, Banu; Kennedy, Kevin J

2013-04-01

Micro-aeration, which refers to the addition of very small amounts of air, is a simple technology that can potentially be incorporated in septic tanks to improve the digestion performance. The purpose of this study was to investigate and compare the effects of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions. 1.6 L batch reactor experiments were carried out in duplicate using raw primary sludge, with 4.1 % total solids, and diluted primary sludge, with 2.1 % total solids. Reactors were operated for 5 weeks at room temperature to simulate septic tank conditions. Micro-aeration rate of 0.00156 vvm effectively solubilised chemical oxygen demand (COD) and improved the subsequent degradation of COD. Micro-aeration also increased the generation of ammonia and soluble proteins, but did not improve the reduction in total and volatile solids, or the reduction in carbohydrates. Experiments using diluted sludge samples showed similar trends as the experiments with raw sludge, which suggest that initial solids concentration did not have a significant effect on the degradation of primary sludge under septic tank conditions.

Benchmark simulation Model no 2 in Matlab-simulink: towards plant-wide WWTP control strategy evaluation.

PubMed

Vreck, D; Gernaey, K V; Rosen, C; Jeppsson, U

2006-01-01

In this paper, implementation of the Benchmark Simulation Model No 2 (BSM2) within Matlab-Simulink is presented. The BSM2 is developed for plant-wide WWTP control strategy evaluation on a long-term basis. It consists of a pre-treatment process, an activated sludge process and sludge treatment processes. Extended evaluation criteria are proposed for plant-wide control strategy assessment. Default open-loop and closed-loop strategies are also proposed to be used as references with which to compare other control strategies. Simulations indicate that the BM2 is an appropriate tool for plant-wide control strategy evaluation.

Retrofitting activated sludge systems to intermittent aeration for nitrogen removal.

PubMed

Hanhan, O; Artan, N; Orhon, D

2002-01-01

The paper provides the basis and the conceptual approach of applying process kinetics and modelling to the design of alternating activated sludge systems for retrofitting existing activated sludge plants to intermittent aeration for nitrogen removal. It shows the significant role of the two specific parameters, namely, the aerated fraction and the cycle time ratio on process performance through model simulations and proposes a way to incorporate them into a design procedure using process stoichiometry and mass balance. It illustrates the effect of these parameters, together with the sludge age, in establishing the balance between the denitrification potential and the available nitrogen created in the anoxic/aerobic sequences of system operation.

Benchmarking nitrogen removal suspended-carrier biofilm systems using dynamic simulation.

PubMed

Vanhooren, H; Yuan, Z; Vanrolleghem, P A

2002-01-01

We are witnessing an enormous growth in biological nitrogen removal from wastewater. It presents specific challenges beyond traditional COD (carbon) removal. A possibility for optimised process design is the use of biomass-supporting media. In this paper, attached growth processes (AGP) are evaluated using dynamic simulations. The advantages of these systems that were qualitatively described elsewhere, are validated quantitatively based on a simulation benchmark for activated sludge treatment systems. This simulation benchmark is extended with a biofilm model that allows for fast and accurate simulation of the conversion of different substrates in a biofilm. The economic feasibility of this system is evaluated using the data generated with the benchmark simulations. Capital savings due to volume reduction and reduced sludge production are weighed out against increased aeration costs. In this evaluation, effluent quality is integrated as well.

Enhanced compositing of radiation disinfected sewage sludge

NASA Astrophysics Data System (ADS)

Kawakami, W.; Hashimoto, S.

Studies on isothermal composting of radiation disinfected sewage sludge and liquid chromatography of water extracts of the products were carried out. The optimum temperature and pH were around 50 °C and 7-8, respectively. The repeated use of products as seeds increased the rate of CO 2 evolution. The rate reached a maximum within 10 hours and decreased rapidly, and the CO 2 evolution ceased after about 3 days. The conversion of organic carbon to carbon dioxide attained to about 40% for the repeated use of products as seeds at the optimum conditions. As long as seeds in available were used, no remarkable difference was found in the composting of unirradiated and irradiated sludges. The composting process using radiation, however, can be carried out at the optimum conditions and is expected to shorten the composting period, because it is not necessary to keep fermentation temperature higher to reduce pathogen in sludge. Liquid chromatographic studies of the products showed that low molecular components decreased and higher molecular ones increased with fermentation. An index expressing the degree of reduction of easily decomposable organics was presented. The index also showed that the optimum temperature for fermentation was 50 °C, and that the easily decomposable organics disappeared above 30% of the conversion of organic carbon.

TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

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

Wiersma, B.

2011-08-24

Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate themore » degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than in the PUREX/oxalic acid environment. (3) The corrosion rates for PUREX/8 wt.% oxalic acid were greater than or equal to those observed for the PUREX/2.5 wt.% oxalic acid. No localized corrosion was observed in the tests with the 8 wt.% oxalic acid. Testing with HM/8 wt.% oxalic acid simulant was not performed. Thus, a comparison with the results with 2.5 wt.% oxalic acid, where the corrosion rate was 88 mpy and localized corrosion was observed at 75 C, cannot be made. (4) The corrosion rates in 1 and 2.5 wt.% oxalic acid solutions were temperature dependent: (a) At 50 C, the corrosion rates ranged between 90 to 140 mpy over the 30 day test period. The corrosion rates were higher under stagnant conditions. (b) At 75 C, the initial corrosion rates were as high as 300 mpy during the first day of exposure. The corrosion rates increased with agitation. However, once the passive ferrous oxalate film formed, the corrosion rate decreased dramatically to less than 20 mpy over the 30 day test period. This rate was independent of agitation. (5) Electrochemical testing indicated that for oxalic acid/sludge simulant mixtures the cathodic reaction has transport controlled reaction kinetics. The literature suggests that the dissolution of the sludge produces a di-oxalatoferrate ion that is reduced at the cathodic sites. The cathodic reaction does not appear to involve hydrogen evolution. On the other hand, electrochemical tests demonstrated that the cathodic reaction for corrosion of carbon steel in pure oxalic acid involves hydrogen evolution. (6) Agitation of the oxalic acid/sludge simulant mixtures typically resulted in a higher corrosion rates for both acid concentrations. The transport of the ferrous ion away from the metal surface results in a less protective ferrous oxalate film. (7) A mercury containing species along with aluminum, silicon and iron oxides was observed on the interior of the pits formed in the HM/2.5 wt.% oxalic acid simulant at 75 C. The pitting rates in the agitated and non-agitated solution were 2 mils/day and 1 mil/day, respectively. A mechanism by which the mercury interacts with the aluminum and silicon oxides in this simulant to accelerate corrosion was proposed.« less

Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting.

PubMed

Zhang, Junya; Sui, Qianwen; Li, Kun; Chen, Meixue; Tong, Juan; Qi, Lu; Wei, Yuansong

2017-04-01

Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A-the control, B-natural zeolite addition, and C-3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites andDMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH 3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance.

Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting.

PubMed

Zhang, Junya; Sui, Qianwen; Li, Kun; Chen, Meixue; Tong, Juan; Qi, Lu; Wei, Yuansong

2016-01-01

Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--natural zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance.

The effects of soil liming and sewage sludge application on dynamics of copper fractions and total copper concentration.

PubMed

Malinowska, Elżbieta

2016-10-01

The paper deals with effects of liming and different doses of municipal sewage sludge (5, 10, and 15 % of soil mass) on copper speciation in soil. In all samples, pH was determined together with total copper concentration, which was measured with the ICP-AES method. Concentration of copper chemical fractions was determined using the seven-step procedure of Zeien and Brümmer. In the soil treated with the highest dose of sludge (15 %), there was, compared to the control, a twofold increase in the concentration of copper and a threefold increase in the concentration of nitrogen. Copper speciation analysis showed that in the municipal sewage sludge the easily soluble and exchangeable fractions (F1 and F2) constituted only a small share of copper with the highest amount of this metal in the organic (F4) and residual (F7) fractions. In the soil, at the beginning of the experiment, the highest share was in the organic fraction (F4), the residual fraction (F7) but also in the fraction where copper is bound to amorphous iron oxides (F5). After 420 days, at the end of the experiment, the highest amount of copper was mainly in the organic fraction (F4) and in the fraction with amorphous iron oxides (F5). Due to mineralization of organic matter in the sewage sludge, copper was released into the soil with the share of the residual fraction (F7) decreasing. In this fraction, there was much more copper in limed soil than in non-limed soil.

Performance intensification of Prague wastewater treatment plant.

PubMed

Novák, L; Havrlíková, D

2004-01-01

Prague wastewater treatment plant was intensified during 1994--1997 by construction of new regeneration tank and four new secondary settling tanks. Nevertheless, more stringent effluent limits and operational problems gave rise to necessity for further intensification and optimisation of plant performance. This paper describes principal operational problems of the plant and shows solutions and achieved results that have lead to plant performance stabilisation. The following items are discussed: low nitrification capacity, nitrification bioaugmentation, activated sludge bulking, insufficient sludge disposal capacity, chemical precipitation of raw wastewater, simultaneous precipitation, sludge chlorination, installation of denitrification zones, sludge rising in secondary settling tanks due to denitrification, dosage of cationic polymeric organic flocculant to secondary settling tanks, thermophilic operation of digestors, surplus activated sludge pre-thickening, mathematical modelling.

Analysis of Perfluorinated Chemicals in Sludge: Method Development and Initial Results

EPA Science Inventory

A fast, rigorous method was developed to maximize the extraction efficacy for ten perfluorocarboxylic acids and perfluorooctanesulfonate from wastewater-treatment sludge and to quantitate using liquid chromatography, tandem-mass spectrometry (LC/MS/MS). First, organic solvents w...

[Amelioration effects of wastewater sludge biochars on red soil acidity and their environmental risk].

PubMed

Lu, Zai-Liang; Li, Jiu-Yu; Jiang, Jun; Xu, Ren-Kou

2012-10-01

Biochars were prepared from wastewater sludge from two wastewater treatment plants in Nanjing using a pyrolysis method at 300, 500 and 700 degrees C. The properties of the biochars were measured, and their amelioration effects on the acidity of a red soil and environmental risk of application of sludge biochars were examined to evaluate the possibility of agricultural application of wastewater sludge biochars in red soils. Results indicated that incorporation of both sludge and sludge biochar increased soil pH due to the alkalinity of sludge and sludge biochar, and the mineralization of organic N and nitrification of ammonium N from wastewater sludge induced soil pH fluctuated during incubation. The amelioration effects of biochars generated at 500 and 700 degrees C on the soil were significantly greater than that of sludge significantly. Sludge and sludge biochar contain ample base cations of Ca2+, Mg2+, K+ and Na+ and thus incorporation of sludge and sludge biochar increased the contents of soil exchangeable base cations and decreased soil exchangeable aluminum and H+. Contents of heavy metals in sludge biochars were greater than these in their feedstock sludge, while the contents of Cu, Pb, Ni and As in sludge biochars were lower than the standard values of heavy metals were wastewater sludge for agricultural use in acid soils in China except for Zn and Cd. The contents of available forms of heavy metals in the biochars generated from sludge from Chengdong wastewater treatment plant was lower than these in the corresponding sludge, suggesting that pyrolysis proceed decreased the activity of heavy metals in wastewater sludge. After 90-day incubation of the soil with sludge and sludge biochar, the differences in the contents of soil available heavy metals were not significant between the biochars and their feedstock sludge from Jiangxizhou wastewater treatment plant, and the contents in the treatments with biochars added was lower than these in the treatments with the corresponding sludge from Chengdong wastewater treatment plant for most of heavy metals. It can be concluded that the biochars from wastewater sludge could be used as soil amendments to adjust soil acidity. Application of sludge biochars did not increase activity and availability of heavy metals compared with direct incorporation of the sludge.

Environmental application for GIS: Assessing Iskandar Malaysia's (IM) sewage sludge for potential biomass resource

NASA Astrophysics Data System (ADS)

Salim, M. R.; Shaharuddin, N.; Abdullah Halim, K.

2014-02-01

The low carbon scenario could be achieved through the identification of major sectors contributing to the emission of high greenhouse gases (GHG) into the atmosphere. Sewage treatment plant (STP) was ranked as one of the major sectors that emits methane gas (CH4) during treatment processes, including sludge treatment. Sludge treatment is also capital extensive with high operational cost. Thus, sewage sludge has been accepted as a nuisance in STP. However, many has claimed that, sludge produced contain organic matter that has the potential for biomass resource. Thus, it would be such a Žwaste? if sludge are directly disposed of into the landfill without utilizing them at its full potential. In order to do so, it is vital to be able to determine the amount of sludge production. This research was implemented in Iskandar Malaysia regions in the state of Johor. By using GIS tool, the regions that produced the most sewage sludge can be determined, and can be group as critical area. Result shows that Nusajaya produces the most, compared to other regions, which indicated Nusajaya as a densely populated region.

Spinel formation for stabilizing simulated nickel-laden sludge with aluminum-rich ceramic precursors.

PubMed

Shih, Kaimin; White, Tim; Leckie, James O

2006-08-15

The feasibility of stabilizing nickel-laden sludge from commonly available Al-rich ceramic precursors was investigated and accomplished with high nickel incorporation efficiency. To simulate the process, nickel oxide was mixed alternatively with gamma-alumina, corundum, kaolinite, and mullite and was sintered from 800 to 1480 degrees C. The nickel aluminate spinel (NiAl2O4) was confirmed as the stabilization phase for nickel and crystallized with efficiencies greater than 90% for all precursors above 1250 degrees C and 3-h sintering. The nickel-incorporation reaction pathways with these precursors were identified, and the microstructure and spinel yield were investigated as a function of sintering temperature with fixed sintering time. This study has demonstrated a promising process for forming nickel spinel to stabilize nickel-laden sludge from a wide range of inexpensive ceramic precursors, which may provide an avenue for economically blending waste metal sludges via the building industry processes to reduce the environmental hazards of toxic metals. The correlation of product textures and nickel incorporation efficiencies through selection of different precursors also provides the option of tailoring property-specific products.

Characteristics of electricity generation and biodegradation in tidal river sludge-used microbial fuel cells.

PubMed

Touch, Narong; Hibino, Tadashi; Nagatsu, Yoshiyuki; Tachiuchi, Kouhei

2014-04-01

The electricity generation behavior of microbial fuel cell (MFC) using the sludge collected from the riverbank of a tidal river, and the biodegradation of the sludge by the electricity generation are evaluated. Although the maximum current density (150-300 mA/m(2)) was higher than that of MFC using freshwater sediment (30 mA/m(2)), the output current was greatly restricted by the mass transfer limitation. However, our results also indicate that placing the anode in different locations in the sludge could reduce the mass transfer limitation. After approximately 3 months, the removal efficiency of organic carbon was approximately 10%, demonstrated that MFC could also enhance the biodegradation of the sludge by nearly 10-fold comparing with the natural biodegradation. We also found that the biodegradation could be identified by the behavior of oxygen consumption of the sludge. Importantly, the oxygen consumption of the sludge became higher along with the electricity generation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Co-fermentation of sewage sludge with ryegrass for enhancing hydrogen production: Performance evaluation and kinetic analysis.

PubMed

Yang, Guang; Wang, Jianlong

2017-11-01

The low C/N ratio and low carbohydrate content of sewage sludge limit its application for fermentative hydrogen production. In this study, perennial ryegrass was added as the co-substrate into sludge hydrogen fermentation with different mixing ratios for enhancing hydrogen production. The results showed that the highest hydrogen yield of 60mL/g-volatile solids (VS) added was achieved when sludge/perennial ryegrass ratio was 30:70, which was 5 times higher than that from sole sludge. The highest VS removal of 21.8% was also achieved when sludge/perennial ryegrass ratio was 30:70, whereas VS removal from sole sludge was only 0.7%. Meanwhile, the co-fermentation system simultaneously improved hydrogen production efficiency and organics utilization of ryegrass. Kinetic analysis showed that the Cone model fitted hydrogen evolution better than the modified Gompertz model. Furthermore, hydrogen yield and VS removal increased with the increase of dehydrogenase activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ex-situ catalytic pyrolysis of wastewater sewage sludge - A micro-pyrolysis study.

PubMed

Wang, Kaige; Zheng, Yan; Zhu, Xifeng; Brewer, Catherine E; Brown, Robert C

2017-05-01

Concerns over increasing amounts of sewage sludge and unsustainability of current disposal methods have led to development of alternative routes for sludge management. The large amount of organics in sewage sludge makes it potential feedstock for energy or fuel production via thermochemical pathways. In this study, ex-situ catalytic pyrolysis using HZSM-5 catalyst was explored for the production of olefinic and aromatic hydrocarbons and nutrient-rich char from sewage sludge. The optimal pyrolysis and catalysis temperatures were found to be 500°C and 600°C, respectively. Carbon yields of hydrocarbons from sewage sludge were higher than for lignocellulose; yield differences were attributed to the high extractives content in the sludge. Full recovery of most inorganic elements were found in the char, which suggests that catalyst deactivation maybe alleviated through ex-situ catalytic pyrolysis. Most of the nitrogen was retained in the char while 31.80% was released as ammonia, which suggests a potential for nitrogen recycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of alkaline addition on anaerobic sludge digestion with combined pretreatment of alkaline and high pressure homogenization.

PubMed

Fang, Wei; Zhang, Panyue; Zhang, Guangming; Jin, Shuguang; Li, Dongyi; Zhang, Meixia; Xu, Xiangzhe

2014-09-01

To improve anaerobic digestion efficiency, combination pretreatment of alkaline and high pressure homogenization was applied to pretreat sewage sludge. Effect of alkaline dosage on anaerobic sludge digestion was investigated in detail. SCOD of sludge supernatant significantly increased with the alkaline dosage increase after the combined pretreatment because of sludge disintegration. Organics were significantly degraded after the anaerobic digestion, and the maximal SCOD, TCOD and VS removal was 73.5%, 61.3% and 43.5%, respectively. Cumulative biogas production, methane content in biogas and biogas production rate obviously increased with the alkaline dosage increase. Considering both the biogas production and alkaline dosage, the optimal alkaline dosage was selected as 0.04 mol/L. Relationships between biogas production and sludge disintegration showed that the accumulative biogas was mainly enhanced by the sludge disintegration. The methane yield linearly increased with the DDCOD increase as Methane yield (ml/gVS)=4.66 DDCOD-9.69. Copyright © 2014 Elsevier Ltd. All rights reserved.

Re-use of drinking water treatment plant (DWTP) sludge: Characterization and technological behaviour of cement mortars with atomized sludge additions

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

Husillos Rodriguez, N., E-mail: nuriah@ietcc.csic.e; Martinez Ramirez, S.; Blanco Varela, M.T.

This paper aims to characterize spray-dried DWTP sludge and evaluate its possible use as an addition for the cement industry. It describes the physical, chemical and micro-structural characterization of the sludge as well as the effect of its addition to Portland cements on the hydration, water demand, setting and mechanical strength of standardized mortars. Spray drying DWTP sludge generates a readily handled powdery material whose particle size is similar to those of Portland cement. The atomized sludge contains 12-14% organic matter (mainly fatty acids), while its main mineral constituents are muscovite, quartz, calcite, dolomite and seraphinite (or clinoclor). Its amorphousmore » material content is 35%. The mortars were made with type CEM I Portland cement mixed with 10 to 30% atomized sludge exhibited lower mechanical strength than the control cement and a decline in slump. Setting was also altered in the blended cements with respect to the control.« less

Differences on nitrogen availability in a soil amended with fresh, composted and thermally-dried sewage sludge.

PubMed

Tarrasón, D; Ojeda, G; Ortiz, O; Alcañiz, J M

2008-01-01

Anaerobically-digested sludge called fresh sludge (F), composted sludge (C) and thermally-drying sludge (T), all from the same batch, were applied to the surface of a calcareous Udic Calciustept with loamy texture. Dosage equivalent was 10 t ha(-1) of dry matter. The concentration of mineral nitrogen (ammonium and nitrate) in the soil was measured in order to estimate the effects of the post-treatments to which the different kinds of sewage sludge are subjected in relation to the availability of N in the surface layer of the soil. The most significant differences in NH(4)-N and NO(3)-N concentrations due to the transformation of the organic matter were observed during the first three weeks following soil amendment. Thermally-dried and composted sludge initially displayed higher concentrations of ammonium and nitrate in soil. Five months after the amendment, soil applied with fresh sludge showed the highest concentrations of NH(4)-N and NO(3)-N (6.1 and 36.6 mg kg(-1), respectively). It is clear that the processes of composting and thermal-drying influence the bioavailability of nitrogen from the different types of sewage sludge.

Environmental application of gamma technology: Update on the Canadian sludge irradiator

NASA Astrophysics Data System (ADS)

Swinwood, Jean F.; Fraser, Frank M.

1993-10-01

Waste treatment and disposal technologies have recently been subjected to increasing public and regulatory scrutiny. Concern for the environment and a heightened awareness of potential health hazards that could result from insufficient or inappropriate waste handling methods have combined to push waste generators in their search for new treatment alternatives. Gamma technology can offer a new option for the treatment of potentially infectious wastes, including municipal sewage sludge. Sewage sludge contains beneficial plant nutrients and a high organic component that make it ideal as a soil conditioning agent or fertilizer bulking material. It also carries potentially infectious microorganisms which limit opportunities for beneficial recycling of sludges. Gamma irradiation-disinfection of these sludges offers a reliable, fast and efficient method for safe sludge recycling. Nordion International's Market Development Division was created in 1987 as part of a broad corporate reorganization. It was given an exclusive mandate to develop new applications of gamma irradiation technology and markets for these new applications. Nordion has since explored and developed opportunities in food irradiation, pharmaceutical/cosmetic products irradiation, biomedical waste sterilization, airline waste disinfection, and sludge disinfection for recycling. This paper focuses on the last of these -a proposed sludge recycling facility that incorporates a cobalt 60 sludge irradiator.

Behaviour of endocrine disrupting chemicals during the treatment of municipal sewage sludge.

PubMed

Ivashechkin, P; Corvini, P F X; Dohmann, M

2004-01-01

Agricultural application of municipal sewage sludge has been emotionally discussed in the last decades, because the latter contains endocrine disrupting chemicals (EDCs) and other organic micropollutants with unknown fate and risk potential. Bisphenol A (BPA) was chosen as a model substance to investigate the influence of sludge conditioning on the end-concentration of EDCs in sludge. Adsorption studies with radioactive-labelled BPA showed that more than 75% BPA in anaerobically digested sludge is bound to solids (log Kd = 2.09-2.30; log Koc = 2.72-3.11). Sludge conditioning with polymer or iron (III) chloride alone had no influence on the adsorption of BPA. After conditioning with iron (III) chloride and calcium hydroxide desorption of BPA took place. Apparently, it occurred due to the deprotonation of BPA (pKa= 10.3) as the pH-value reached 12.4 during the process. The same behaviour is expected for other phenolic EDCs with similar pKa (nonylphenol, 17beta-estradiol, estron, estriol, 17alpha-ethinylestradiol). This study shows high affinity of BPA to the anaerobically digested sludge and importance of conditioning in the elimination of EDCs during the sludge treatment. Addition of polymer is favourable in the case of sludge incineration. Conditioning with iron (III) chloride and calcium hydroxide shows advantages for the use of sludge as fertiliser.

The presence and role of bacterial quorum sensing in activated sludge

PubMed Central

Chong, Grace; Kimyon, Onder; Rice, Scott A.; Kjelleberg, Staffan; Manefield, Mike

2012-01-01

Summary Activated sludge used for wastewater treatment globally is composed of a high‐density microbial community of great biotechnological significance. In this study the presence and purpose of quorum sensing via N‐acylated‐l‐homoserine lactones (AHLs) in activated sludge was explored. The presence of N‐heptanoyl‐l‐homoserine lactone in organic extracts of sludge was demonstrated along with activation of a LuxR‐based AHL monitor strain deployed in sludge, indicating AHL‐mediated gene expression is active in sludge flocculates but not in the bulk aqueous phase. Bacterial isolates from activated sludge were screened for AHL production and expression of phenotypes commonly but not exclusively regulated by AHL‐mediated gene transcription. N‐acylated‐l‐homoserine lactone and exoenzyme production were frequently observed among the isolates. N‐acylated‐l‐homoserine lactone addition to sludge upregulated chitinase activity and an AHL‐ and chitinase‐producing isolate closely related to Aeromonas hydrophila was shown to respond to AHL addition with upregulation of chitinase activity. N‐acylated‐l‐homoserine lactones produced by this strain were identified and genes ahyI/R and chiA, encoding AHL production and response and chitinase activity respectively, were sequenced. These experiments provide insight into the relationship between AHL‐mediated gene expression and exoenzyme activity in activated sludge and may ultimately create opportunities to improve sludge performance. PMID:22583685

Coagulation efficiency and flocs characteristics of recycling sludge during treatment of low temperature and micro-polluted water.

PubMed

Zhou, Zhiwei; Yang, Yanling; Li, Xing; Gao, Wei; Liang, Heng; Li, Guibai

2012-01-01

Drinking water treatment sludge, characterized as accumulated suspended solids and organic and inorganic matter, is produced in large quantities during the coagulation process. The proper disposal, regeneration or reuse of sludge is, therefore, a significant environmental issue. Reused sludge at low temperatures is an alternative method to enhance traditional coagulation efficiency. In the present study, the recycling mass of mixed sludge and properties of raw water (such as pH and turbidity) were systematically investigated to optimize coagulation efficiency. We determined that the appropriate dosage of mixed sludge was 60 mL/L, effective initial turbidity ranges were below 45.0 NTU, and optimal pH for DOMs and turbidity removal was 6.5-7.0 and 8.0, respectively. Furthermore, by comparing the flocs characteristics with and without recycling sludge, we found that floc structures with sludge were more irregular with average size growth to 64.7 microm from 48.1 microm. Recycling sludge was a feasible and successful method for enhancing pollutants removal, and the more irregular flocs structure after recycling might be caused by breakage of reused flocs and incorporation of powdered activated carbon into larger flocs structure. Applied during the coagulation process, recycling sludge could be significant for the treatment of low temperature and micro-polluted source water.

A super high-rate sulfidogenic system for saline sewage treatment.

PubMed

Tsui, To-Hung; Chen, Lin; Hao, Tianwei; Chen, Guang-Hao

2016-11-01

This study proposes a novel approach to resolve the challenging issue of sludge bed clogging in a granular sulfate-reducing upflow sludge bed (GSRUSB) reactor by means of introducing intermittent gas sparging to advance it into a super high-rate anaerobic bioreactor. Over a 196-day lab-scale trial, the GSRUSB system was operated from nominal hydraulic retention time of 4-hr to 40-min and achieved the highest organic loading rate of 13.31 kg COD/m 3 ·day which is substantially greater than the typical loading of 2.0-3.5 kg COD/m 3 ·day in a conventional upflow anaerobic sludge bed reactor treating dilute organic strength wastewater. The average organic removal efficiency and total dissolved sulfide of this system were 90 ± 4.2% and 158 ± 28 mg S/L, while organics residual in the effluent was 34 ± 14 mg COD/L. The control stage (without gas sparging) revealed that the sludge bed clogging happened concomitantly with the significant drop in extracellular polymeric substance content of granular sludge, through relevant chemical measurements and confocal laser scanning microscopy analyses. On the other hand, compared with increasing the effluent recirculation ratio (from 1.4 to 5), the three-dimensional computational fluid dynamics modeling in combination with energy dissipation analysis demonstrated that the gas sparging (at a superficial gas velocity of 0.8 m s -1 ) can create a 23 times higher liquid shear as well as enhanced particle attrition. Overall, this study not only developed a super high-rate anaerobic bioreactor for saline sewage treatment, but also shed light on the role of intermittent gas sparging in control of sludge bed clogging for anaerobic bioreactors. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of sewage sludge application on soil properties and willow (Salix sp.) cultivation.

PubMed

Urbaniak, Magdalena; Wyrwicka, Anna; Tołoczko, Wojciech; Serwecińska, Liliana; Zieliński, Marek

2017-05-15

The aim of the study was to determine the impact of sewage sludge from three wastewater treatment plants of different sizes (small, medium and large) applied in two doses (3 and 9 tons per hectare) on soil properties, determined as the content of organic carbon and humus fractions, bacterial abundance, phytotoxicity and PCDD/PCDF TEQ concentrations. The study also evaluated the impact of this sewage sludge on the biometric and physiological parameters and detoxification reaction of willow (Salix sp.) as a typical crop used for the remediation of soil following sludge application. The cultivation of willow on soil treated with sludge was found to result in a gradual increase of humus fractions, total organic carbon content and bacterial abundance as well as soil properties measured using Lepidium sativum. However, it also produced an initial increase of soil phytotoxicity, indicated by Sinapis alba and Sorghum sacharatum, and PCDD/PCDF Toxic Equivalent (TEQ) concentrations, which then fell during the course of the experiment, particularly in areas planted by willow. Although the soil phytotoxicity and PCDD/PCDF TEQ content of the sewage sludge-amended soil initially increased, sludge application was found to have a positive influence on willow, probably due to its high nutrient and carbon content. The obtained results reveal increases in willow biomass, average leaf surface area and leaf length as well as chlorophyll a+b content. Moreover, a strong decline was found in the activity of the detoxifying enzyme glutathione S-transferase (GSTs), a multifunctional enzyme involved in the metabolism of xenobiotics in plants, again demonstrating the used sludge had a positive influence on willow performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Microbiological hazards resulting from application of dairy sewage sludge: effects on occurrence of pathogenic microorganisms in soil.

PubMed

Jezierska-Tys, Stefania; Frac, Magdalena; Tys, Jerzy

2010-01-01

The aims of this study were to (1) examine the extent of bacterial contamination of soils subjected to exposure to dairy sewage sludge applied to soils as measured by determination of number of bacteria from the Escherichia coli family and (2) determine the effects of dairy sewage sludge and straw on populations of other microbial species present in gray-brown podzolic soil. The gray-brown podzolic soil was formed from heavy loamy sand, which is characterized by the following granulometric composition: a sand fraction, 65%; a silt fraction, 19%; and a silt and clay fraction; 16%. The brown soil was formed from silt-loam and characterized by the following granulometric composition of silty-clay deposit: sand fraction, 8%; silt fraction, 48%; and clay and silt fraction, 46%. In dairy sewage sludge the total bacteria number as defined by Alef and Nannipieri (1995) was 51 x 10(4) colony-forming units (cfu)/ kg dry matter (dm), fungi total number 10 x 10(3) cfu/ kg dm, and E. coli bacteria 9.5 x 10(3) most probable number (MPN)/kg dm. In dairy sewage sludge mixed with straw, total number of bacteria and total number of fungi decreased to 10(3) and 10(2), respectively. Competition for nitrogen, glucose, and lactose and organic acids such as acetic and succinic with soil microorganisms, as well as soil conditions such as lack of oxygen, lower soil pH, and temperature, may account for the reduction in the number of E. coli bacteria in soils to which dairy sewage sludge was applied. Dairy sewage sludge may provide a beneficial impact on soil environment and adversely affect microorganisms such that dairy sewage sludge may be used as a safe organic fertilizer.

Ion Trapping of Amines in Protozoa: A Novel Removal Mechanism for Micropollutants in Activated Sludge.

PubMed

Gulde, Rebekka; Anliker, Sabine; Kohler, Hans-Peter E; Fenner, Kathrin

2018-01-02

To optimize removal of organic micropollutants from the water cycle, understanding the processes during activated sludge treatment is essential. In this study, we hypothesize that aliphatic amines, which are highly abundant among organic micropollutants, are partly removed from the water phase in activated sludge through ion trapping in protozoa. In ion trapping, which has been extensively investigated in medical research, the neutral species of amine-containing compounds diffuse through the cell membrane and further into acidic vesicles present in eukaryotic cells such as protozoa. There they become trapped because diffusion of the positively charged species formed in the acidic vesicles is strongly hindered. We tested our hypothesis with two experiments. First, we studied the distribution of the fluorescent amine acridine orange in activated sludge by confocal fluorescence imaging. We observed intense fluorescence in distinct compartments of the protozoa, but not in the bacterial biomass. Second, we investigated the distribution of 12 amine-containing and eight control micropollutants in both regular activated sludge and sludge where the protozoa had been inactivated. In contrast to most control compounds, the amine-containing micropollutants displayed a distinctly different behavior in the noninhibited sludge compared to the inhibited one: (i) more removal from the liquid phase; (ii) deviation from first-order kinetics for the removal from the liquid phase; and (iii) higher amounts in the solid phase. These results provide strong evidence that ion trapping in protozoa occurs and that it is an important removal mechanism for amine-containing micropollutants in batch experiments with activated sludge that has so far gone unnoticed. We expect that our findings will trigger further investigations on the importance of this process in full-scale wastewater treatment systems, including its relevance for accumulation of ammonium.

Cultivation of activated sludge using sea mud as seed to treat industrial phenolic wastewater with high salinity.

PubMed

Tan, Songwen; Cui, Chunzhi; Hou, Yang; Chen, Xuncai; Xu, Aiqin; Li, Weiguo; You, Hong

2017-01-30

A technique is proposed to treat saline hazardous wastewater by using marine activated sludge, cultivated with sea mud as seed. Since the developed marine activated sludge had phenol-tolerant microorganisms (MAS-1, MAS-2 and MAS-3) which originated from the ocean, it was envisaged that these bacteria could survive and breakdown phenol in saline environments. In this work, typical phenol-tolerant microorganisms were isolated from the marine activated sludge and identified. After a hierarchical acclimation process, the marine activated sludge was used to treat the industrial phenolic wastewater with high salinity. The marine activated sludge was able to break down phenol and other organic components effectively and efficiently in treating the wastewater with salinity of 5.7% w/v. The results showed a high removal of phenol (99%), COD (80%) and NH 3 -N (68%). Copyright © 2016 Elsevier Ltd. All rights reserved.

Electricity generation from bio-treatment of sewage sludge with microbial fuel cell.

PubMed

Jiang, Junqiu; Zhao, Qingliang; Zhang, Jinna; Zhang, Guodong; Lee, Duu-Jong

2009-12-01

A two-chambered microbial fuel cell (MFC) with potassium ferricyanide as its electron acceptor was utilized to degrade excess sewage sludge and to generate electricity. Stable electrical power was produced continuously during operation for 250 h. Total chemical oxygen demand (TCOD) of sludge was reduced by 46.4% when an initial TCOD was 10,850 mg/l. The MFC power output did not significantly depend on process parameters such as substrate concentration, cathode catholyte concentration, and anodic pH. However, the MFC produced power was in close correlation with the soluble chemical oxygen demand (SCOD) of sludge. Furthermore, ultrasonic pretreatment of sludge accelerated organic matter dissolution and, hence, TCOD removal rate in the MFC was increased, but power output was insignificantly enhanced. This study demonstrates that this MFC can generate electricity from sewage sludge over a wide range of process parameters.

Influence of ultrasonication on anaerobic bioconversion of sludge.

PubMed

Mao, Taohong; Show, Kuan-Yeow

2007-04-01

The influence of ultrasonication on hydrolysis, acidogenesis, and methanogenesis in anaerobic decomposition of sludge was investigated. The sonicated sludge exhibited prehydrolysis and preacidogenesis effects in the anaerobic decomposition process. First-order hydrolysis rates increased from 0.0384 day(-1) in the control digester to 0.0672 day(-1) in the digester fed, with sludge sonicated at 0.52 W/mL. The sonication appeared to be ineffective in relation to acidogenesis reaction rates, but it provided a better buffering capacity to diminish the adverse effect of acidification. Digesters fed with sonicated sludge demonstrated enhanced methanogenesis over the control unit. Determination by coenzyme F420 verified that sonication is able to promote the growth of methanogenic biomass and facilitate a positive methanogenic microbial development in suppressing the initial methanogenesis limitation. The results suggest that ultrasonication could enhance anaerobic decomposition of sludge, resulting in an accelerated bioconversion, improved organics degradation, improved biogas production, and increased methane content.

Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

PubMed

Grübel, Klaudiusz; Suschka, Jan

2015-05-01

The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9 days MAD + 15 days TAD. Similar results were obtained for volatile solids (VS) reduction after two-stage anaerobic digestion. The highest decrease of VS was obtained when the first stage, the mesophilic digestion which lasted 7 days, was followed by thermophilic digestion for 17 days.

Utilization and Conversion of Sewage Sludge as Metal Sorbent

NASA Astrophysics Data System (ADS)

Gong, Xu Dong; Li, Loretta Y.

2013-04-01

Most biosolids are disposed on land. With improvements in wastewater treatment processes and upgrading of treatment plants across Canada, biosolids generation will increase dramatically. These biosolids will need to be dealt with because they contain various contaminants, including heavy metals and several classes of emerging contaminants. A number of researchers have recently focused on preparation of sewage sludge-based adsorbents by carbonation, physical activation and chemical activation for decontamination of air and wastewater. These previous studies have indicated that sludge-based activated carbon can have good adsorption performance for organic substances in dye wastewater. The overall results suggest that activated carbon from sewage sludge can produce a useful adsorbent, while also reducing the amount of sewage sludge to be disposed. However, sludge-derived activated carbon has not been extensively studied, especially for adsorption of heavy metal ions in wastewater and for its capacity to remove emerging contaminants, such as poly-fluorinated compounds (PFCs). Previous research has indicated that commercial activated carbons adsorb organic compounds more efficiently than heavy metal ions. 45 Activated carbon can be modified to enhance its adsorption capacity for special heavy metal ions,46 e.g. by addition of inorganic and organic reagents. The modifications which are successful for commercial activated carbon should also be effective for sludge-derived activated carbon, but this needs to be confirmed. Our research focuses on (a) investigation of techniques for converting sewage sludge (SS) to activated carbon (AC) as sorbents; (b) exploration of possible modification of the activated carbon (MAC) to improve its sorption capacity; (c) examination of the chemical stability of the activated carbon and the leachability of contaminants from activated carbon,; (d) comparison of adsorptivity with that of other sorbents. Based on XRD and FT-IR, we successfully converted SS to AC and further modified it to improve absorption. SSMAC has large specific surface areas based on the BET technique. Batch adsorption results indicate that metal adsorption for SSMAC > SSAC, with adsorption occurring within the first 5 minutes of contact. Comparison of the adsorptivity of various sorbents such as commercial activated carbon (CAC), mineral sorbents such as perlite, clinoptilolite and illite indicates that SSMAC × CAC × clinoptilolite > kaolite.

Sewage sludge stabilisation and fertiliser value in a silvopastoral system developed with Eucalyptus nitens Maiden in Lugo (Spain).

PubMed

Mosquera-Losada, M R; Ferreiro-Domínguez, N; Daboussi, S; Rigueiro-Rodríguez, A

2016-10-01

Copper (Cu) is one of the heavy metals with highest proportion in sewage sludge. In Europe, sewage sludge should be stabilised before using it as a fertiliser in agriculture. Depending on the stabilisation process, sewage sludge has different Cu contents, and soil Cu incorporation rates. This study was undertaken to examine the effect of fertilisation with different types of sewage sludge (anaerobic, composted, and pelletised) on the concentration of total and available Cu in the soil, the tree growth, the pasture production, and the concentration of Cu in the pasture when compared with control treatments (i.e. no fertilisation and mineral fertilisation) in a silvopastoral system under Eucalyptus nitens Maiden. The results of this experiment show that an improvement of the soil pH increased the incorporation and the mineralisation of the sewage sludge and litter, and therefore, the release of Cu from the soil. Moreover, the concentration of Cu in the pasture and the levels of Cu extracted by the pasture improved when the soil organic matter decreased because the high levels of organic matter in the soil could have formed Cu complex. The composted sewage sludge (COM) increased a) the soil variables studied (pH, total Cu, and available Cu) and b) the Cu extracted by the pasture, both probably due to the higher inputs of cations made with it. In any case, the levels of Cu found in the soil never exceeded the maximums as set by Spanish regulations and did not cause harmful effects on the plants and animals. Therefore, the use of COM as an organic fertiliser should be promoted in silvopastoral systems established in edaphoclimatic conditions similar to this study because COM enhanced the productivity of the system from a viewpoint of the soil and the pasture, without causing any environmental damage. Copyright © 2016 Elsevier B.V. All rights reserved.

Combined effects of Fenton peroxidation and CaO conditioning on sewage sludge thermal drying.

PubMed

Liu, Huan; Liu, Peng; Hu, Hongyun; Zhang, Qiang; Wu, Zhenyu; Yang, Jiakuan; Yao, Hong

2014-12-01

Joint application of Fenton's reagent and CaO can dramatically enhance sludge dewaterability, thus are also likely to affect subsequent thermal drying process. This study investigated the synergistic effects of the two conditioners on the thermal drying behavior of sewage sludge and the emission characteristics of main sulfur-/nitrogen-containing gases. According to the results, Fenton peroxidation combined with CaO conditioning efficiently promoted sludge heat transfer, reduced the amounts of both free and bound water, and created porous structure in solids to provide evaporation channels, thus producing significant positive effects on sludge drying performance. In this case, the required time for drying was shortened to one-third. Additionally, joint usage of Fenton's reagent and CaO did not increase the losses of organic matter during sludge drying process. Meanwhile, they facilitated the formation of sulfate and sulfonic acid/sulfone, leading to sulfur retention in dried sludge. Both of Fenton peroxidation and CaO conditioning promoted the oxidation, decomposition, and/or dissolution of protein and inorganic nitrogen in sludge pre-treatment. As a consequence, the emissions of sulfurous and nitrogenous gases from dewatered sludge drying were greatly suppressed. These indicate that combining Fenton peroxidation with CaO conditioning is a promising strategy to improve drying efficiency of sewage sludge and to control sulfur and nitrogen contaminants during sludge thermal drying process. Copyright © 2014 Elsevier Ltd. All rights reserved.

PROCESS DESIGN MANUAL: LAND APPLICATION OF ...

EPA Pesticide Factsheets

Land application of sewage sludge generated by domestic sewage treatment is performed in an environmentally safe and cost–effective manner in many communities. Land application involves taking advantage of the fertilizing and soil conditioning properties of sewage sludge by spreading the sewage sludge on the soil surface, incorporating or injecting the sewage sludge into soil, or spraying the sewage sludge. Because sewage sludge disposal practices (e.g., landfilling) are becoming less available and more costly, and because of the increasing desire to beneficially reuse waste residuals whenever possible, land application is increasingly chosen as a sewage sludge use or disposal practice. Approximately 33 percent of the 5.4 million dry metric tons of sewage sludge generated annually in the United States at publicly owned treatment works (POTWs) is land applied. Of the sewage sludge that is land applied, approximately 67% is land applied on agricultural lands, 3% on forest lands, approximately 9% on reclamation sites, and 9% on public contact sites; 12% is sold or given away in a bag or other container for application to the land (Federal Register, Vol. 58, No. 32, February 19, 1993). In addition, approximately 8.6 billion gallons of domestic septage is generated annually. Land application of sewage sludge has been practiced in many countries for centuries so that the nutrients (e.g., nitrogen, phosphorus) and organic matter in sewage sludge can be beneficia

HELMINTH OVA AND VIRUS DETECTION IN BIOSOLIDS

EPA Science Inventory

Sewage sludge (also known as biosolids), a byproduct from domestic sewage treatment, is often used as an organic soil conditioner and fertilizer. Raw sludge must be treated to reduce levels of potential human pathogenic agents before being used for this purpose. The domestic us...

Use of Fenton reaction for the treatment of leachate from composting of different wastes.

PubMed

Trujillo, Daniel; Font, Xavier; Sánchez, Antoni

2006-11-02

The oxidation of leachate coming from the composting of two organic wastes (wastewater sludge and organic fraction of municipal solid wastes) using the Fenton's reagent was studied using different ratios [Fe(2+)]/[COD](0) and maintaining a ratio [H(2)O(2)]/[COD](0) equal to 1. The optimal conditions for Fenton reaction were found at a ratio [Fe(2+)]/[COD](0) equal to 0.1. Both leachates were significantly oxidized under these conditions in terms of COD removal (77 and 75% for leachate from wastewater sludge composting and leachate from organic fraction of municipal solid wastes, respectively) and BOD(5) removal (90 and 98% for leachate from wastewater sludge composting and leachate from organic fraction of municipal solid wastes, respectively). Fenton's reagent was found to oxidize preferably biodegradable organic matter of leachate. In consequence, a decrease in the biodegradability of leachates was observed after Fenton treatment for both leachates. Nevertheless, Fenton reaction proved to be a feasible technique for the oxidation of the leachate under study, and it can be considered a suitable treatment for this type of wastewaters.

Correlation models for waste tank sludges and slurries

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

Mahoney, L.A.; Trent, D.S.

This report presents the results of work conducted to support the TEMPEST computer modeling under the Flammable Gas Program (FGP) and to further the comprehension of the physical processes occurring in the Hanford waste tanks. The end products of this task are correlation models (sets of algorithms) that can be added to the TEMPEST computer code to improve the reliability of its simulation of the physical processes that occur in Hanford tanks. The correlation models can be used to augment, not only the TEMPEST code, but other computer codes that can simulate sludge motion and flammable gas retention. This reportmore » presents the correlation models, also termed submodels, that have been developed to date. The submodel-development process is an ongoing effort designed to increase our understanding of sludge behavior and improve our ability to realistically simulate the sludge fluid characteristics that have an impact on safety analysis. The effort has employed both literature searches and data correlation to provide an encyclopedia of tank waste properties in forms that are relatively easy to use in modeling waste behavior. These properties submodels will be used in other tasks to simulate waste behavior in the tanks. Density, viscosity, yield strength, surface tension, heat capacity, thermal conductivity, salt solubility, and ammonia and water vapor pressures were compiled for solutions and suspensions of sodium nitrate and other salts (where data were available), and the data were correlated by linear regression. In addition, data for simulated Hanford waste tank supernatant were correlated to provide density, solubility, surface tension, and vapor pressure submodels for multi-component solutions containing sodium hydroxide, sodium nitrate, sodium nitrite, and sodium aluminate.« less

Preparation of biochar from sewage sludge

NASA Astrophysics Data System (ADS)

Nieto, Aurora; María Méndez, Ana; Gascó, Gabriel

2013-04-01

Biomass waste materials appropriate for biochar production include crop residues (both field residues and processing residues such as nut shells, fruit pits, bagasse, etc), as well as yard, food and forestry wastes, and animal manures. Biochar can and should be made from biomass waste materials and must not contain unacceptable levels of toxins such as heavy metals which can be found in sewage sludge and industrial or landfill waste. Making biochar from biomass waste materials should create no competition for land with any other land use option—such as food production or leaving the land in its pristine state. Large amounts of agricultural, municipal and forestry biomass are currently burned or left to decompose and release CO2 and methane back into the atmosphere. They also can pollute local ground and surface waters—a large issue for livestock wastes. Using these materials to make biochar not only removes them from a pollution cycle, but biochar can be obtained as a by-product of producing energy from this biomass. Sewage sludge is a by-product from wastewater treatment plants, and contains significant amounts of heavy metals, organic toxins and pathogenic microorganisms, which are considered to be harmful to the environment and all living organisms. Agricultural use, land filling and incineration are commonly used as disposal methods. It was, however, reported that sewage sludge applications in agriculture gives rise to an accumulation of harmful components (heavy metals and organic compounds) in soil. For this reason, pyrolysis can be considered as a promising technique to treat the sewage sludge including the production of fuels. The objective of this work is to study the advantages of the biochar prepared from sewage sludge.

Simultaneous Fluorescent Gram Staining and Activity Assessment of Activated Sludge Bacteria

PubMed Central

Forster, Scott; Snape, Jason R.; Lappin-Scott, Hilary M.; Porter, Jonathan

2002-01-01

Wastewater treatment is one of the most important commercial biotechnological processes, and yet the component bacterial populations and their associated metabolic activities are poorly understood. The novel fluorescent dye hexidium iodide allows assessment of Gram status by differential absorption through bacterial cell walls. Differentiation between gram-positive and gram-negative wastewater bacteria was achieved after flow cytometric analysis. This study shows that the relative proportions of gram-positive and gram-negative bacterial cells identified by traditional microscopy and hexidium iodide staining were not significantly different. Dual staining of cells for Gram status and activity proved effective in analyzing mixtures of cultured bacteria and wastewater populations. Levels of highly active organisms at two wastewater treatment plants, both gram positive and gram negative, ranged from 1.5% in activated sludge flocs to 16% in the activated sludge fluid. Gram-positive organisms comprised <5% of the total bacterial numbers but accounted for 19 and 55% of the highly active organisms within flocs at the two plants. Assessment of Gram status and activity within activated sludge samples over a 4-day period showed significant differences over time. This method provides a rapid, quantitative measure of Gram status linked with in situ activity within wastewater systems. PMID:12324319

Supercritical water oxidation treatment of textile sludge.

PubMed

Zhang, Jie; Wang, Shuzhong; Li, Yanhui; Lu, Jinling; Chen, Senlin; Luo, XingQi

2017-08-01

In this work, we studied the supercritical water oxidation (SCWO) of the textile sludge, the hydrothermal conversion of typical textile compounds and the corrosion properties of stainless steel 316. Moreover, the influence mechanisms of NaOH during these related processes were explored. The results show that decomposition efficiency for organic matter in liquid phase of the textile sludge was improved with the increment of reaction temperature or oxidation coefficient. However, the organic substance in solid phase can be oxidized completely in supercritical water. Serious coking occurred during the high pressure water at 250-450°C for the Reactive Orange 7, while at 300 and 350°C for the polyvinyl alcohol. The addition of NaOH not only accelerated the destruction of organic contaminants in the SCWO reactor, but effectively inhibited the dehydration conversion of textile compounds during the preheating process, which was favorable for the treatment system of textile sludge. The corrosion experiment results indicate that the stainless steel 316 could be competent for the body materials of the reactor and the heat exchangers. Furthermore, there was prominent enhancement of sodium hydroxide for the corrosion resistance of 316 in subcritical water. On the contrary the effect was almost none during SCWO.

Simultaneous fluorescent gram staining and activity assessment of activated sludge bacteria.

PubMed

Forster, Scott; Snape, Jason R; Lappin-Scott, Hilary M; Porter, Jonathan

2002-10-01

Wastewater treatment is one of the most important commercial biotechnological processes, and yet the component bacterial populations and their associated metabolic activities are poorly understood. The novel fluorescent dye hexidium iodide allows assessment of Gram status by differential absorption through bacterial cell walls. Differentiation between gram-positive and gram-negative wastewater bacteria was achieved after flow cytometric analysis. This study shows that the relative proportions of gram-positive and gram-negative bacterial cells identified by traditional microscopy and hexidium iodide staining were not significantly different. Dual staining of cells for Gram status and activity proved effective in analyzing mixtures of cultured bacteria and wastewater populations. Levels of highly active organisms at two wastewater treatment plants, both gram positive and gram negative, ranged from 1.5% in activated sludge flocs to 16% in the activated sludge fluid. Gram-positive organisms comprised <5% of the total bacterial numbers but accounted for 19 and 55% of the highly active organisms within flocs at the two plants. Assessment of Gram status and activity within activated sludge samples over a 4-day period showed significant differences over time. This method provides a rapid, quantitative measure of Gram status linked with in situ activity within wastewater systems.

Reducing capacities and redox potentials of humic substances extracted from sewage sludge.

PubMed

Yang, Zhen; Du, Mengchan; Jiang, Jie

2016-02-01

Humic substances (HS) are redox active organic materials that can be extracted from sewage sludge generated in wastewater treatment processes. Due to the poor understanding of reducing capacity, redox potentials and redox active functional groups of HS in sewage sludge, the potential contribution of sludge HS in transformation of wastewater contaminants is unclear. In the present study, the number of electrons donated or accepted by sewage sludge HS were quantified before and after reduction by iron compounds that possess different redox potentials and defined as the reducing capacity of the sewage sludge. In contrast to previous studies of soil and commercial humic acids (HA), reduced sludge HA showed a lower reducing capacity than that of native HA, which implies formation of semiquinone radicals since the semiquinone radical/hydroquinone pair has a much higher redox potential than the quinone/hydroquinone pair. It is novel that reducing capacities of sludge HA were determined in the redox potential range from -314 to 430 mV. The formation of semiquinone radicals formed during the reduction of quinone moieties in sludge HA is shown by three-dimensional excitation/emission matrix fluorescence spectroscopies information, increasing fluorescence intensities and blue-shifting of the excitation/emission peak of reduced sludge HA. Knowledge of sludge HS redox potentials and corresponding reducing capacities makes it possible to predict the transformation of redox active pollutants and facilitate manipulation and optimization of sludge loading wastewater treatment processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Priority and emerging pollutants in sewage sludge and fate during sludge treatment.

PubMed

Mailler, R; Gasperi, J; Chebbo, G; Rocher, V

2014-07-01

This paper aims at characterizing the quality of different treated sludges from Paris conurbation in terms of micropollutants and assessing their fate during different sludge treatment processes (STP). To achieve this, a large panel of priority and emerging pollutants (n=117) have been monitored in different STPs from Parisian wastewater treatment plants including anaerobic digestion, thermal drying, centrifugation and a sludge cake production unit. Considering the quality of treated sludges, comparable micropollutant patterns are found for the different sludges investigated (in mg/kg DM - dry matter). 35 compounds were detected in treated sludges. Some compounds (metals, organotins, alkylphenols, DEHP) are found in every kinds of sludge while pesticides or VOCs are never detected. Sludge cake is the most contaminated sludge, resulting from concentration phenomenon during different treatments. As regards treatments, both centrifugation and thermal drying have broadly no important impact on sludge contamination for metals and organic compounds, even if a slight removal seems to be possible with thermal drying for several compounds by abiotic transfers. Three different behaviors can be highlighted in anaerobic digestion: (i) no removal (metals), (ii) removal following dry matter (DM) elimination (organotins and NP) and iii) removal higher than DM (alkylphenols - except NP - BDE 209 and DEHP). Thus, this process allows a clear removal of biodegradable micropollutants which could be potentially significantly improved by increasing DM removal through operational parameters modifications (retention time, temperature, pre-treatment, etc.). Copyright © 2014 Elsevier Ltd. All rights reserved.

Ecotoxicity of arsenic contaminated sludge after mixing with soils and addition into composting and vermicomposting processes.

PubMed

Vašíčková, Jana; Maňáková, Blanka; Šudoma, Marek; Hofman, Jakub

2016-11-05

Sludge coming from remediation of groundwater contaminated by industry is usually managed as hazardous waste despite it might be considered for further processing as a source of nutrients. The ecotoxicity of phosphorus rich sludge contaminated with arsenic was evaluated after mixing with soil and cultivation with Sinapis alba, and supplementation into composting and vermicomposting processes. The Enchytraeus crypticus and Folsomia candida reproduction tests and the Lactuca sativa root growth test were used. Invertebrate bioassays reacted sensitively to arsenic presence in soil-sludge mixtures. The root elongation of L. sativa was not sensitive and showed variable results. In general, the relationship between invertebrate tests results and arsenic mobile concentration was indicated in majority endpoints. Nevertheless, significant portion of the results still cannot be satisfactorily explained by As chemistry data. Composted and vermicomposted sludge mixtures showed surprisingly high toxicity on all three tested organisms despite the decrease in arsenic mobility, probably due to toxic metabolites of bacteria and earthworms produced during these processes. The results from the study indicated the inability of chemical methods to predict the effects of complex mixtures on living organisms with respect to ecotoxicity bioassays. Copyright © 2016 Elsevier B.V. All rights reserved.

Waste-Activated Sludge Fermentation for Polyacrylamide Biodegradation Improved by Anaerobic Hydrolysis and Key Microorganisms Involved in Biological Polyacrylamide Removal.

PubMed

Dai, Xiaohu; Luo, Fan; Zhang, Dong; Dai, Lingling; Chen, Yinguang; Dong, Bin

2015-07-06

During the anaerobic digestion of dewatered sludge, polyacrylamide (PAM), a chemical conditioner, can usually be consumed as a carbon and nitrogen source along with other organic matter (e.g., proteins and carbohydrates in the sludge). However, a significant accumulation of acrylamide monomers (AMs) was observed during the PAM biodegradation process. To improve the anaerobic hydrolysis of PAM, especially the amide hydrolysis process, and to avoid the generation of the intermediate product AM, a new strategy is reported herein that uses an initial pH of 9, 200 mg COD/L of PAM and a fermentation time of 17 d. First, response surface methodology (RSM) was applied to optimize PAM removal in the anaerobic digestion of the sludge. The biological hydrolysis of PAM reached 86.64% under the optimal conditions obtained from the RSM. Then, the mechanisms for the optimized parameters that significantly improved the biological hydrolysis of PAM were investigated by the synergistic effect of the main organic compounds in the sludge, the floc size distribution, and the enzymatic activities. Finally, semi-continuous-flow experiments for a microbial community study were investigated based on the determination of key microorganisms involved in the biological hydrolysis of PAM.

Potential and optimization of two-phase anaerobic digestion of oil refinery waste activated sludge and microbial community study

PubMed Central

Wang, Qinghong; Liang, Ying; Zhao, Peng; Li, Qing X.; Guo, Shaohui; Chen, Chunmao

2016-01-01

Oil refinery waste activated sludge produced from oil wastewater biological treatment is a major industrial sludge. Two-phase anaerobic digestion of oil refinery waste activated sludge was studied for the first time. Thermal pretreatment under 170 °C is effective on sludge solubilization. At the optimum hydrolytic-acidogenic condition which was pH of 6.5, temperature of 55 °C and HRT of 2 days, 2754 mg/L volatile fatty acids (VFAs) were produced and acetic acid and butyric acid were the key components. Comparative studies of single-phase and two-phase anaerobic digestion in terms of organic removal, biogas production and methane concentration were conducted. The cumulative methane production and soluble COD (SCOD) removal efficiency in the two-phase system were 228 mL/g COD added and 77.8%, respectively, which were 1.6 and 2.1 times higher than those in single-phase anaerobic digestion. Such improved performance is attributed to intensification of dominant microbial population in separated reactors. Caloramator, Ureibacillus, Dechloromonas, Petrobacter, and T78 played important roles in hydrolytic-acidification and oil-organics degradation. Syntrophic bacteria in the family Porphyromonadaceae and the genus Anaerobranca provide acetate for methanogen. The results demonstrated the potential and operating condition of two-phase anaerobic digestion in treatment of oil refinery waste activated sludge. PMID:27905538

[Treatment of carbonization effluent by the ultrasonic radiation and activated sludge process].

PubMed

Ning, Ping; Xu, Jinqiu; Huang, Dongbin; Ma, Xiaoli; Xu, Xiaojun; Li, Ziyan

2003-05-01

The paper deals with the degradation of organic pollutants by the ultrasonic irradiation-activated sludge process. The treatment of the real coking wastewater of Kunming coke making-gas plant was studied with the water quality model. Using the ultrasonic irradiation-activated sludge process the organic pollutants in the real coking wastewater can be degraded effectively. The influence factors of the ultrasonic degradation effect such as initial concentration, aerated gas and ultrasonic density were investigated and mechanism was explored. The result shows that the ultrasonic degradation effect was high with the decrease of initial concentration of the CODCr, the presence of aerated gas and the increase of ultrasonic density. At the initial CODCr concentration of 807 mg/L, when air acted as aerated gas and only air itself (no ultrasound) was exerted on the wastewater, the degradation rate of the CODCr will be 4.5%. However, when the ultrasound of the intensity of 119.4 kW/m2 was exerted on the wastewater, the degradation rate of the CODCr will be 65%. Compared with the activated sludge process alone, the combination of the ultrasonic irradiation and activated sludge process can increase the degradation rate of the CODCr from 45% to 81%. The oxygen consumption rate of the carbonization effluent obviously decreased in the presence of the activated sludge. This shows the carbonization effluent is not biotoxic behind the ultrasonic irradiation.

Potential and optimization of two-phase anaerobic digestion of oil refinery waste activated sludge and microbial community study

NASA Astrophysics Data System (ADS)

Wang, Qinghong; Liang, Ying; Zhao, Peng; Li, Qing X.; Guo, Shaohui; Chen, Chunmao

2016-12-01

Oil refinery waste activated sludge produced from oil wastewater biological treatment is a major industrial sludge. Two-phase anaerobic digestion of oil refinery waste activated sludge was studied for the first time. Thermal pretreatment under 170 °C is effective on sludge solubilization. At the optimum hydrolytic-acidogenic condition which was pH of 6.5, temperature of 55 °C and HRT of 2 days, 2754 mg/L volatile fatty acids (VFAs) were produced and acetic acid and butyric acid were the key components. Comparative studies of single-phase and two-phase anaerobic digestion in terms of organic removal, biogas production and methane concentration were conducted. The cumulative methane production and soluble COD (SCOD) removal efficiency in the two-phase system were 228 mL/g COD added and 77.8%, respectively, which were 1.6 and 2.1 times higher than those in single-phase anaerobic digestion. Such improved performance is attributed to intensification of dominant microbial population in separated reactors. Caloramator, Ureibacillus, Dechloromonas, Petrobacter, and T78 played important roles in hydrolytic-acidification and oil-organics degradation. Syntrophic bacteria in the family Porphyromonadaceae and the genus Anaerobranca provide acetate for methanogen. The results demonstrated the potential and operating condition of two-phase anaerobic digestion in treatment of oil refinery waste activated sludge.

Coupled heating/acidification pretreatment of chemical sludge for dewatering by using waste sulfuric acid at low temperature.

PubMed

Bian, Bo; Zhang, Limin; Zhang, Qin; Zhang, Shaopeng; Yang, Zhen; Yang, Weiben

2018-08-01

A cost-effective approach for pretreatment of chemical sludge for further dewatering, based on the idea of "using waste to treat waste", is provided. It is a coupled heating/acidification pretreatment method, where waste sulfuric acid is employed and relatively low temperatures (<100 °C) are applied. Effects of reaction time, temperature, and dosage of waste acid on dewatering performance (both dewatering speed and degree) are studied. Under the optimal conditions (reaction time: 30 min; temperature: 90 °C; waste acid dosage: 0.175 g/(g dried sludge)), the method of this work demonstrates three advantages compared to the conventional method using lime+polyacrylamide: lower moisture content of treated sludge; higher calorific value for incineration process; and lower cost. Detailed mechanism of the pretreatment for dewatering is investigated via characterizations and statistical analyses of various parameters, among which zeta potential, particle size, protein and polysaccharide contents, soluble chemical oxygen demand (SCOD), reduction of combined water and volatile suspended solid (VSS), are associated with dewatering performance. Both heating and acidification generate disintegration of cells in sludge, giving rise to two phenomena: more organic matters are released into solution and more bound water turns into free water. Meantime, the released organic polymers flocculate sludge particles, further accelerating the solid-liquid separation process. Copyright © 2018 Elsevier Ltd. All rights reserved.

Improving bioelectricity generation and COD removal of sewage sludge in microbial desalination cell.

PubMed

Ebrahimi, Atieh; Yousefi Kebria, Daryoush; Darzi, Ghasem Najafpour

2018-05-01

Improving wastewater treatment process and water desalination are two important solutions for increasing the available supply of fresh water. Microbial desalination cells (MDCs) with common electrolytes display relatively low organic matter removal and high cost. In this study, sewage sludge was used as the substrate in the Microbial desalination cell (MDC) under three different initial salt concentrations (5, 20 and 35 g.L -1 ) and the maximum salt removal rates of 50.6%, 64% and 69.6% were obtained under batch condition, respectively. The MDC also produced the maximum power density of 47.1 W m -3 and the averaged chemical oxygen demand (COD) removal of 58.2 ± 0.89% when the initial COD was 6610 ± 83 mg L -1 . Employing treated sludge as catholyte enhanced COD removal and power density to 87.3% and 54.4 W m -3 , respectively, with counterbalancing pH variation in treated effluent. These promising results showed, for the first time, that the excess sewage sludge obtained from biological wastewater treatment plants could be successfully used as anolyte and catholyte in MDC, achieving organic matter biodegradation along with salt removal and energy production. In addition, using treated sludge as catholyte will improve the performance of MDC and introduce a more effective method for both sludge treatment and desalination.

Microbial Internal Storage Alters the Carbon Transformation in Dynamic Anaerobic Fermentation.

PubMed

Ni, Bing-Jie; Batstone, Damien; Zhao, Bai-Hang; Yu, Han-Qing

2015-08-04

Microbial internal storage processes have been demonstrated to occur and play an important role in activated sludge systems under both aerobic and anoxic conditions when operating under dynamic conditions. High-rate anaerobic reactors are often operated at a high volumetric organic loading and a relatively dynamic profile, with large amounts of fermentable substrates. These dynamic operating conditions and high catabolic energy availability might also facilitate the formation of internal storage polymers by anaerobic microorganisms. However, so far information about storage under anaerobic conditions (e.g., anaerobic fermentation) as well as its consideration in anaerobic process modeling (e.g., IWA Anaerobic Digestion Model No. 1, ADM1) is still sparse. In this work, the accumulation of storage polymers during anaerobic fermentation was evaluated by batch experiments using anaerobic methanogenic sludge and based on mass balance analysis of carbon transformation. A new mathematical model was developed to describe microbial storage in anaerobic systems. The model was calibrated and validated by using independent data sets from two different anaerobic systems, with significant storage observed, and effectively simulated in both systems. The inclusion of the new anaerobic storage processes in the developed model allows for more successful simulation of transients due to lower accumulation of volatile fatty acids (correction for the overestimation of volatile fatty acids), which mitigates pH fluctuations. Current models such as the ADM1 cannot effectively simulate these dynamics due to a lack of anaerobic storage mechanisms.

Two Cases of Tsunami Dust Pneumonia: Organizing Pneumonia Caused by the Inhalation of Dried Tsunami Sludge after the 2011 Great East Japan Earthquake.

PubMed

Yamanda, Shinsuke; Kobayashi, Seiichi; Hanagama, Masakazu; Sato, Hikari; Suzuki, Satoshi; Ueda, Shinsaku; Takahashi, Toru; Yanai, Masaru

We report two cases of organizing pneumonia (OP) secondary to the inhalation of the dried tsunami sludge which formed during the 2011 Great East Japan Earthquake and the consequent tsunami. After the disaster, both of these patients had been engaged in the restoration work. About half a month later, they developed shortness of breath and pulmonary infiltrates. These patients were diagnosed with interstitial pneumonia. Their biopsy specimens revealed multifocal peribronchiolitis and OP. An electron probe microanalysis of these specimens demonstrated the presence of elements from the earth's crust in the inflammatory lesions. These two cases indicate that exposure to dried tsunami sludge can cause OP.

Cavitation for improved sludge conversion into biogas

NASA Astrophysics Data System (ADS)

Stoop, A. H.; Bakker, T. W.; Kramer, H. J. M.

2015-12-01

In several studies the beneficial influence of pre-treatment of waste activated sludge with cavitation on the biogas production was demonstrated. It is however, still not fully certain whether this effect should be mainly contributed to an increase in conversion rate of organics into biogas by anaerobic bacteria, and how much cavitation increases the total biogas yield. An increase in yield is only the case if cavitation can further disrupt otherwise inaccessible cell membrane structures and long chain organic molecules. In this study the influence of hydrodynamic cavitation on sludge that was already digested for 30 days was investigated. The total biogas yield could indeed be increased. The effect of the backpressure behind the venturi tube on the yield could not yet be established.

Spectroscopic study of the humification process during sewage sludge treatment

NASA Astrophysics Data System (ADS)

Pajączkowska, J.; Sułkowska, A.; Sułkowski, W. W.; Jędrzejczyk, M.

2003-06-01

The aim of this work was to study the free radical transition of organic materials during the sewage treatment process. Investigations of sludge from biologic-mechanical sewage treatment plant in Sosnowiec Zagórze were carried out. The course of the humification processes during sewage treatment was studied by electron paramagnetic resonance (EPR) technique. The concentration of free radicals at each process stage and the value g were determined. Sludge samples and extracted fractions of humic acids were examined. Humic acids were extracted from sludge by means of conventional methods elaborated by Stevenson. For study of humic acids structures, besides EPR, the UV-Vis and IR spectroscopy were used.

Chesapeake Bay nutrient pollution: contribution from the land application of sewage sludge in Virginia.

PubMed

Land, Lynton S

2012-11-01

Human health concerns and the dissemination of anthropogenic substances with unknown consequences are the reasons most often given why disposal of municipal sewage sludge in landfills or using the organic waste as biofuel is preferable to land application. But no "fertilizer" causes more nitrogen pollution than sludge when applied according to Virginia law. Poultry litter is the only other "fertilizer" that causes more phosphorus pollution than sludge. Cost savings by the few farmers in Virginia who use sludge are far less than the costs of the nitrogen pollution they cause. A ban on the land application of all forms of animal waste is very cost-effective and would reduce Chesapeake Bay nutrient pollution by 25%. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biological testing of a digested sewage sludge and derived composts.

PubMed

Moreira, R; Sousa, J P; Canhoto, C

2008-11-01

Aiming to evaluate a possible loss of soil habitat function after amendment with organic wastes, a digested sewage sludge and derived composts produced with green residues, where biologically tested in the laboratory using soil animals (Eisenia andrei and Folsomia candida) and plants (Brassica rapa and Avena sativa). Each waste was tested mimicking a field application of 6ton/ha or 12ton/ha. Avoidance tests did not reveal any impact of sludge and composts to soil biota. Germination and growth tests showed that application of composts were beneficial for both plants. Composts did not affect earthworm's mass increase or reproduction, but the highest sludge amendment revealed negative effects on both parameters. Only the amendment of composts at the highest dose originated an impairment of springtails reproductive output. We suggest that bioassays using different test species may be an additional tool to evaluate effects of amendment of organic wastes in soil. Biological tests are sensitive to pollutants at low concentrations and to interactions undetected by routine chemical analysis.

Usage of pumice as bulking agent in sewage sludge composting.

PubMed

Wu, Chuandong; Li, Weiguang; Wang, Ke; Li, Yunbei

2015-08-01

In this study, the impacts of reused and sucrose-decorated pumice as bulking agents on the composting of sewage sludge were evaluated in the lab-scale reactor. The variations of temperature, pH, NH3 and CO2 emission rate, moisture content (MC), volatile solid, dissolved organic carbon, C/N and the water absorption characteristics of pumice were detected during the 25days composting. The MC of pumice achieved 65.23% of the 24h water absorptivity within the first 2h at the mass ratio of 0.6:1 (pumice:sewage sludge). Reused pumice increased 23.68% of CO2 production and reduced 21.25% of NH3 emission. The sucrose-decorated pumice reduced 43.37% of nitrogen loss. These results suggested that adding pumice and sucrose-decorated pumice in sludge composting matrix could not only adjust the MC of materials, but also improve the degradation of organic matters and reduce nitrogen loss. Copyright © 2015 Elsevier Ltd. All rights reserved.

Energy and phosphorus recovery from black water.

PubMed

de Graaff, M S; Temmink, H; Zeeman, G; Buisman, C J N

2011-01-01

Source-separated black water (BW) (toilet water) containing 38% of the organic material and 68% of the phosphorus in the total household waste (water) stream including kitchen waste, is a potential source for energy and phosphorus recovery. The energy recovered, in the form of electricity and heat, is more than sufficient for anaerobic treatment, nitrogen removal and phosphorus recovery. The phosphorus balance of an upflow anaerobic sludge blanket reactor treating concentrated BW showed a phosphorus conservation of 61% in the anaerobic effluent. Precipitation of phosphate as struvite from this stream resulted in a recovery of 0.22 kgP/p/y, representing 10% of the artificial phosphorus fertiliser production in the world. The remaining part of the phosphorus ended up in the anaerobic sludge, mainly due to precipitation (39%). Low dilution and a high pH favour the accumulation of phosphorus in the anaerobic sludge and this sludge could be used as a phosphorus-enriched organic fertiliser, provided that it is safe regarding heavy metals, pathogens and micro-pollutants.

Conditioning of sewage sludge by Fenton's reagent combined with skeleton builders.

PubMed

Liu, Huan; Yang, Jiakuan; Shi, Yafei; Li, Ye; He, Shu; Yang, Changzhu; Yao, Hong

2012-06-01

Physical conditioners, often known as skeleton builders, are commonly used to improve the dewaterability of sewage sludge. This study evaluated a novel joint usage of Fenton's reagent and skeleton builders, referred to as the F-S inorganic composite conditioner, focusing on their efficacies and the optimization of the major operational parameters. The results demonstrate that the F-S composite conditioner for conditioning sewage sludge is a viable alternative to conventional organic polymers, especially when ordinary Portland cement (OPC) and lime are used as the skeleton builders. Experimental investigations confirmed that Fenton reaction required sufficient time (80 min in this study) to degrade organics in the sludge. The optimal condition of this process was at pH=5, Fe(2+)=40 mg g(-1) (dry solids), H(2)O(2)=32 mg g(-1), OPC=300 mg g(-1) and lime=400 mg g(-1), in which the specific resistance to filtration reduction efficiency of 95% was achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

Process performance of high-solids batch anaerobic digestion of sewage sludge.

PubMed

Liao, Xiaocong; Li, Huan; Cheng, Yingchao; Chen, Nan; Li, Chenchen; Yang, Yuning

2014-01-01

The characteristics of high-solids anaerobic digestion (AD) of sewage sludge were investigated by comparison with conventional low-solids processes. A series of batch experiments were conducted under mesophilic condition and the initial solid contents were controlled at four levels of 1.79%, 4.47%, 10.28% and 15.67%. During these experiments, biogas production, organic degradation and intermediate products were monitored. The results verified that high-solids batch AD of sewage sludge was feasible. Compared with the low-solids AD with solid contents of 1.79% or 4.47%, the high-solids processes decreased the specific biogas yield per gram of sludge volatile solids slightly, achieved the same organic degradation rate of about 40% within extended degradation time, but increased the volumetric biogas production rate and the treatment capability of digesters significantly. The blocked mass and energy transfer, the low substrate to inoculum rate and the excessive cumulative free ammonia were the main factors impacting the performance of high-solids batch AD.

Towards understanding the effects of additives on the vermicomposting of sewage sludge.

PubMed

Xing, Meiyan; Lv, Baoyi; Zhao, Chunhui; Yang, Jian

2015-03-01

This work evaluated the effects of additives on the chemical properties of the final products (vermicompost) from vermicomposting of sewage sludge and the adaptable characteristics of Eisenia fetida during the process. An experimental design with different ratios of sewage sludge and the additives (cattle dung or pig manure) was conducted. The results showed that the vermicomposting reduced total organic carbon and the quotient of total organic carbon to total nitrogen (C/N ratio) of the initial mixtures and enhanced the stability and agronomical value of the final products. Notably, principal component analysis indicated that the additives had significant effects on the characteristics of the vermicomposts. Moreover, the vermibeds containing cattle dung displayed a better earthworm growth and reproduction than those with pig manure. Additionally, redundancy analysis demonstrated that electrical conductivity (EC), pH, and C/N ratio played crucial roles on earthworm growth and reproduction. In all, the additives with high C/N ratio, pH buffering capacity, and low EC are recommended to be used for vermicomposting of sewage sludge.

[Effect of simulated heavy metal leaching solution of electroplating sludge on the bioactivity of Acidithiobacillus ferrooxidans].

PubMed

Xie, Xin-Yuan; Sun, Pei-De; Lou, Ju-Qing; Guo, Mao-Xin; Ma, Wang-Gang

2013-01-01

An Acidithiobacillus ferrooxidans strain WZ-1 was isolated from the tannery sludge in Wenzhou, Zhejiang Province in China. The cell of WZ-1 strain is Gram negative and rod-shaped, its 16S rDNA sequence is closely related to that of Acidithiobacillus ferrooxidans ATCC23270 with 99% similarity. These results reveal that WZ-1 is a strain of Acidithiobacillus ferrooxidans. The effects of Ni2+, Cr3+, Cu2+, Zn2+ and 5 kinds of simulated leaching solutions of electroplating sludge on the bioactivity of Fe2+ oxidation and apparent respiratory rate of WZ-1 were investigated. The results showed that Ni2+ and Cr3+ did not have any influence on the bioactivity of WZ-1 at concentrations of 5.0 g x L(-1) and 0.1 g x L(-1), respectively. WZ-1 showed tolerance to high levels of Ni2+, Zn2+ (about 30.0 g x L(-1)), but it had lower tolerance to Cr3+ and Cu2+ (0.1 g x L(-1) Cr3+ and 2.5 g x L(-1) Cu2+). Different kinds of simulated leaching solution of electroplating sludge had significant differences in terms of their effects on the bioactivity of WZ-1 with a sequence of Cu/Ni/Cr/Zn > Cu/Ni/Zn > Cu/Cr/Zn > Cu/Ni/Cr > Ni/Cr/Zn.

Improved volatile fatty acids anaerobic production from waste activated sludge by pH regulation: Alkaline or neutral pH?

PubMed

Ma, Huijun; Chen, Xingchun; Liu, He; Liu, Hongbo; Fu, Bo

2016-02-01

In this study, the anaerobic fermentation was carried out for volatile fatty acids (VFAs) production at different pH (between 7.0 and 10.0) conditions with untreated sludge and heat-alkaline pretreated waste activated sludge. In the fermentation with untreated sludge, the extent of hydrolysis of organic matters and extent of acidification at alkaline pH are 54.37% and 30.37%, respectively, resulting in the highest VFAs yield at 235.46mg COD/gVS of three pH conditions. In the fermentation with heat-alkaline pretreated sludge, the acidification rate and VFAs yield at neutral pH are 30.98% and 240.14mg COD/gVS, respectively, which are higher than that at other pH conditions. With the glucose or bovine serum albumin as substrate for VFAs production, the neutral pH showed a higher VFAs concentration than the alkaline pH condition. The results of terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that the alkaline pH caused low microbial richness. Based on the results in this study, we demonstrated that the alkaline pH is favor of hydrolysis of organic matter in sludge while neutral pH improved the acidogenesis for the VFAs production from sludge. Our finding is obvious different to the previous research and helpful for the understanding of how heat-alkaline pretreatment and alkaline fermentation influence the VFAs production, and beneficial to the development of VFAs production process. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Microbial Communities and Their Performances in Anaerobic Hybrid Sludge Bed-Fixed Film Reactor for Treatment of Palm Oil Mill Effluent under Various Organic Pollutant Concentrations

PubMed Central

Meesap, Kanlayanee; Boonapatcharoen, Nimaradee; Techkarnjanaruk, Somkiet; Chaiprasert, Pawinee

2012-01-01

The anaerobic hybrid reactor consisting of sludge and packed zones was operated with organic pollutant loading rates from 6.2 to 8.2 g COD/L day, composed mainly of suspended solids (SS) and oil and grease (O&G) concentrations between 5.2 to 10.2 and 0.9 to 1.9 g/L, respectively. The overall process performance in terms of chemical oxygen demands (COD), SS, and O&G removals was 73, 63, and 56%, respectively. When the organic pollutant concentrations were increased, the resultant methane potentials were higher, and the methane yield increased to 0.30 L CH4/g CODremoved. It was observed these effects on the microbial population and activity in the sludge and packed zones. The eubacterial population and activity in the sludge zone increased to 6.4 × 109 copies rDNA/g VSS and 1.65 g COD/g VSS day, respectively, whereas those in the packed zone were lower. The predominant hydrolytic and fermentative bacteria were Pseudomonas, Clostridium, and Bacteroidetes. In addition, the archaeal population and activity in the packed zone were increased from to 9.1 × 107 copies rDNA/g VSS and 0.34 g COD-CH4/g VSS day, respectively, whereas those in the sludge zone were not much changed. The most represented species of methanogens were the acetoclastic Methanosaeta, the hydrogenotrophic Methanobacterium sp., and the hydrogenotrophic Methanomicrobiaceae. PMID:22927723

Transport of sludge-derived organic pollutants to deep-sea sediments at deep water dump site 106

USGS Publications Warehouse

Takada, H.; Farrington, J.W.; Bothner, Michael H.; Johnson, C.G.; Tripp, B.W.

1994-01-01

Linear alkylbenzenes (LABs), coprostanol and epi-coprostanol, were detected in sediment trap and bottom sediment samples at the Deep Water Dump Site 106 located 185 km off the coast of New Jersey, in water depths from 2400 to 2900 m. These findings clearly indicate that organic pollutants derived from dumped sludge are transported through the water column and have accumulated on the deep-sea floor. No significant difference in LABs isomeric composition was observed among sludge and samples, indicating little environmental biodegradation of these compounds. LABs and coprostanol have penetrated down to a depth of 6 cm in sediment, indicating the mixing of these compounds by biological and physical processes. Also, in artificially resuspended surface sediments, high concentrations of LABs and coprostanols were detected, implying that sewage-derived organic pollutants initially deposited on the deep-sea floor can be further dispersed by resuspension and transport processes. Small but significant amounts of coprostanol were detected in the sediment from a control site at which no LABs were detected. The coprostanol is probably derived from feces of marine mammals and sea birds and/or from microbial or geochemical transformations of cholesterol. Polcyclic aromatic hydrocarbons (PAHs) in sediment trap samples from the dump site were largely from the sewage sludge and had a mixed petroleum and pyrogenic composition. In contrast, PAHs in sediments in the dump site were mainly pyrogenic; contributed either from sewage sludge or from atmospheric transport to the overlying waters. & 1994 American Chemical Society.

[Improvement of municipal sewage sludge dewaterability by bioleaching: a pilot-scale study with sequence batch reaction model].

PubMed

Liu, Fen-Wu; Zhou, Li-Xiang; Zhou, Jun; Jiang, Feng; Wang, Dian-Zhan

2011-07-01

To observe the bioleaching effect on sewage sludge dewaterability, three consecutive batch bioleaching experiments were conducted through a bioleaching bio-reactor with 700 L of working volume. Subsequently, the bioleached sludge was dewatered by using chamber filter press. The results show that the 1st batch bioleaching process can be finished within 90 hours if the aeration amount was 1.2 m3/h with the 1: 15 mixing ratio of bioleached sludge to raw sludge. The pH of sludge declines from initial 6.11 to 2.33 while ORP increased from initial -134 mV to finial 507 mV. The specific resistance to filtration (SRF) of the tested sludge was decreased from original 1.00 x 10(13) m/kg to final 0.09 x 10(13) m/kg after bioleaching. For the subsequent two batch trials, the bioleaching process can be finished in 40 hours and 46 hours, respectively. Likewise, sludge SRF is also significantly decreased to 0.19 x 10(13) m/kg and 0.36 x 10(13) m/kg if the mixing ratio of bioleached sludge to fresh sludge is 1:1 although the microbial nutrient substance dosage is reduced by 25% and 50% for 2nd, and 3rd batch experiments, respectively. The harvested bioleached sludge from three batch trails is dewatered by chamber filter press with 0.3-0.4 MPa working pressure for 2 hours. It is found that the moisture of dewatered sludge cake can be reduced to 58%, and that the dewatered sludge cake is of khaki appearance and didn't emit any offensive odor. In addition, it is also observes that sludge organic matter only changed a bit from 52.9% to 48.0%, but 58% of sludge-borne Cu and 88% of sludge-borne Zn can be removed from sludge by bioleaching process. Therefore, dual goals for sludge-borne heavy metal removal and sludge dewatering of high efficiency can be achieved simultaneously through the approach mentioned above. Therefore, bioleaching technique is of great engineering application for the treatment of sewage sludge.

Biodegradation of total organic carbons (TOC) in Jordanian petroleum sludge.

PubMed

Mrayyan, Bassam; Battikhi, Mohammed N

2005-04-11

Biodegradation is cost-effective, environmentally friendly treatment for oily contaminated sites by the use of microorganisms. In this study, laboratory experiments were conducted to establish the performance of bacterial isolates in degradation of organic compounds contained in oily sludge from the Jordanian Oil Refinery plant. As a result of the laboratory screening, three natural bacterial consortia capable of degrading total organic carbons (TOC) were prepared from isolates enriched from the oil sludge. Experiments were conducted in Erlenmeyer flasks under aerobic conditions, with TOC removal percentage varied from 0.3 to 28% depending on consortia type and concentration. Consortia 7B and 13B exhibited the highest TOC removal percentage of 28 and 22%, respectively, before nutrient addition. TOC removal rate was enhanced after addition of nutrients to incubated flasks. The highest TOC reduction (43%) was estimated after addition of combination of nitrogen, phosphorus and sulphur to consortia 7B. A significant variation (P<0.005) was observed between the effect of consortia type and concentration on TOC% reduction. No significant variation was observed between incubation at 10 and 18 days in TOC% reduction. This is the first report concerning biological treatment of TOC by bacteria isolated from the oil refinery plants, where it lays the ground for full integrated studies recommended for the degradation of organic compounds that assist in solving sludge problems.

Changes of chromium speciation and organic matter during low-temperature pyrolysis of tannery sludge.

PubMed

Zhou, Jianjun; Ma, Hongrui; Gao, Mao; Sun, Wenyue; Zhu, Chao; Chen, Xiangping

2018-01-01

The application or disposal of char derived from tannery sludge is directly influenced by the mobility and bioavailability of Cr during pyrolysis process. This study focused on the changes of Cr speciation and organic matter in tannery sludge during low-temperature pyrolysis (100-400 °C) to evaluate the toxicity of char in terms of the leaching possibility of Cr. The results showed that (1) lower char yield and more porous structure were observed after pyrolysis. (2) Higher pyrolysis temperature increased Cr content in the char; however, Cr in this case was converted into the residual fraction which minimized its bioavailability therefore lowers its potential risk to the environment. (3) Organic matters in the acid and alkali leachates were mainly humic acid-like substance, and condensed organic matter might appear at 200 °C and then destruct. (4) Despite the comparatively high content of Cr in the char, the leaching toxicity of char was within the security range according to the national standard of China. The Cr content in the acid and alkali leachates decreased to the range of 16.5-35.3 and 0.2-6.8 mg/L, respectively. It was suggested that the potential toxicity of tannery sludge from Cr could be reduced before utilization or disposal by pyrolysis, especially under 400 °C.

Research Findings on Heat Treatment of Pathogens and Indicator Organisms

EPA Science Inventory

Heat or thermal treatment has been used for many years for reducing the densities of pathogens in food and beverages. Its application for disinfection of municipal sludges has occurred only recently. One method for achieving Class A biosolids is to thermally treat sludges either ...

RESOURCES CONSERVATIONS COMPANY - B.E.S.T. SOLVENT EXTRACTION TECHNOLOGY - APPLICATIONS ANALYSIS REPORT

EPA Science Inventory

This document is an evaluation of the performance of the Resources Conservation Company (RCC) Basic Extractive Sludge Treatment (B.E.S.T.®) solvent extraction technology and its applicability as a treatment technique for soils, sediments, and sludges contaminated with organics. B...

Effect of temperature on solids reductions and on degradation kinetics during thermophilic aerobic digestion of a simulated sludge.

PubMed

Toki, C J

2008-07-01

Laboratory-scale experiments were conducted to determine the influence of higher thermophilic temperatures on thermophilic aerobic digestion treatment of a simulated sludge. The efficiency of the process was evaluated in respect of solids removal and degradation rate constants at four thermophilic temperatures. Batch runs were operated at a retention time of one day and temperatures of 65, 70, 72 and 75 degrees C. The results indicated that temperature increase did not impart any significant benefits to the digestion operation in terms of suspended solids and biochemichal oxygen demand reduction. The findings from this research also suggested that the treatment would not appear to benefit from temperatures higher than 65 degrees C, as classically suggested by Van't Hoff-Arrhenius. Therefore, increase of thermophilic temperature in the tested 65-75 degrees C range does not enhance the efficiency of thermophilic, aerobic sludge digestion treatment.

Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes.

PubMed

Liu, Huan; Luo, Guang-Qian; Hu, Hong-Yun; Zhang, Qiang; Yang, Jia-Kuan; Yao, Hong

2012-10-15

Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH(3)), sulfur dioxide (SO(2)), hydrogen sulfide (H(2)S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO(2) and H(2)S emissions in the H(2)SO(4) conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant release of NH(3). Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of energy consumption during aerobic sewage sludge treatment in dairy wastewater treatment plant.

PubMed

Dąbrowski, Wojciech; Żyłka, Radosław; Malinowski, Paweł

2017-02-01

The subject of the research conducted in an operating dairy wastewater treatment plant (WWTP) was to examine electric energy consumption during sewage sludge treatment. The excess sewage sludge was aerobically stabilized and dewatered with a screw press. Organic matter varied from 48% to 56% in sludge after stabilization and dewatering. It proves that sludge was properly stabilized and it was possible to apply it as a fertilizer. Measurement factors for electric energy consumption for mechanically dewatered sewage sludge were determined, which ranged between 0.94 and 1.5 kWhm -3 with the average value at 1.17 kWhm -3 . The shares of devices used for sludge dewatering and aerobic stabilization in the total energy consumption of the plant were also established, which were 3% and 25% respectively. A model of energy consumption during sewage sludge treatment was estimated according to experimental data. Two models were applied: linear regression for dewatering process and segmented linear regression for aerobic stabilization. The segmented linear regression model was also applied to total energy consumption during sewage sludge treatment in the examined dairy WWTP. The research constitutes an introduction for further studies on defining a mathematical model used to optimize electric energy consumption by dairy WWTPs. Copyright © 2016 Elsevier Inc. All rights reserved.

An examination of the treatment of iron-dosed waste activated sludge by anaerobic digestion.

PubMed

Johnson, D K; Carliell-Marquet, C M; Forster, C F

2003-08-01

Anaerobic digestion is an important sludge treatment process enabling stabilisation of the organic fraction of sewage sludge prior to land application. Any practice which might retard the anaerobic digestion process will jeopardize the stability of the resulting digested sludge. This paper reports on an investigation into the relative digestibility of iron-dosed waste activated sludge (WAS) from a sewage treatment works (STW) with chemical phosphorus removal (CPR), in comparison to WAS from a works without phosphorus removal. Two laboratory scale anaerobic digesters (51) were fed initially with non iron-dosed WAS (Works M) at a solids retention time of 19 days. After 2 months the iron-dosed CPR sludge (Works R) was introduced into the second digester, resulting in a 32% decrease in biogas production and an increase in the methane content of the biogas from an average of 74% to 81%. Pre-treatment of the CPR sludge with sodium sulphide and shear, both alone and in combination, caused the gas production to deteriorate further. Pre-acidification and pre-treatment with EDTA did result in an enhanced gas production but it was still not comparable with that of the digester being fed with non-iron-dosed sludge. The daily gas production was found to be linearly related to the amount of bound iron in the sludge.

Properties of wastepaper sludge in geopolymer mortars for masonry applications.

PubMed

Yan, Shiqin; Sagoe-Crentsil, Kwesi

2012-12-15

This paper presents the results of an investigation into the use of wastepaper sludge in geopolymer mortar systems for manufacturing construction products. The investigation was driven by the increasing demand for reuse options in paper-recycling industry. Both fresh and hardened geopolymer mortar properties are evaluated for samples incorporating dry wastepaper sludge, and the results indicate potential end-use benefits in building product manufacture. Addition of wastepaper sludge to geopolymer mortar reduces flow properties, primarily due to dry sludge absorbing water from the binder mix. The average 91-day compressive strength of mortar samples incorporating 2.5 wt% and 10 wt% wastepaper sludge respectively retained 92% and 52% of the reference mortar strength. However, contrary to the normal trend of increasing drying shrinkage with increasing paper sludge addition to Portland cement matrices, the corresponding geopolymer drying shrinkage decreased by 34% and 64%. Equally important, the water absorption of hardened geopolymer mortar decreased with increasing paper sludge content at ambient temperatures, providing good prospects of overall potential for wastepaper sludge incorporation in the production of building and masonry elements. The results indicate that, despite its high moisture absorbance due to the organic matter and residual cellulose fibre content, wastepaper sludge appears compatible with geopolymer chemistry, and hence serves as a potential supplementary additive to geopolymer cementitious masonry products. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhancement of waste activated sludge aerobic digestion by electrochemical pre-treatment.

PubMed

Song, Li-Jie; Zhu, Nan-Wen; Yuan, Hai-Ping; Hong, Ying; Ding, Jin

2010-08-01

Electrochemical technology with a pair of RuO(2)/Ti mesh plate electrode is first applied to pre-treat Waste Activated Sludge (WAS) prior to aerobic digestion in this study. The effects of various operating conditions were investigated including electrolysis time, electric power, current density, initial pH of sludge and sludge concentration. The study showed that the sludge reduction increased with the electrolysis time, electric power or current density, while decreased with the sludge concentration. Additionally, higher or lower pH than 7.0 was propitious to remove organic matters. The electrochemical pre-treatment removed volatile solids (VS) and volatile suspended solids (VSS) by 2.75% and 7.87%, respectively, with a WAS concentration of 12.9 g/L, electrolysis time of 30 min, electric power of 5 W and initial sludge pH of 10. In the subsequent aerobic digestion, the sludge reductions for VS and VSS after solids retention time (SRT) of 17.5 days were 34.25% and 39.59%, respectively. However, a SRT of 23.5 days was necessary to achieve equivalent reductions without electrochemical pre-treatment. Sludge analysis by Scanning Electron Microscope (SEM) images and infrared (IR) spectra indicated that electrochemical pre-treatment can rupture sludge cells, remove and solubilize intracellular substances, especially protein and polysaccharide, and consequently enhance the aerobic digestion. (c) 2010 Elsevier Ltd. All rights reserved.

Effects of sewage sludge fertilizer on heavy metal accumulation and consequent responses of sunflower (Helianthus annuus).

PubMed

Belhaj, Dalel; Elloumi, Nada; Jerbi, Bouthaina; Zouari, Mohamed; Abdallah, Ferjani Ben; Ayadi, Habib; Kallel, Monem

2016-10-01

Use of sewage sludge, a biological residue produced from sewage treatment processes in agriculture, is an alternative disposal technique of waste. To study the usefulness of sewage sludge amendment for Helianthus annuus, a pot experiment was conducted by mixing sewage sludge at 2.5, 5, and 7.5 % (w/w) amendment ratios to the agricultural soil. Soil pH decreased whereas electrical conductivity, organic matter, total N, available P, and exchangeable Na, K, and Ca increased in soil amended with sewage sludge in comparison to unamended soil. Sewage sludge amendment led to significant increase in Pb, Ni, Cu, Cr, and Zn concentrations of soil. The increased concentration of heavy metals in soil due to sewage sludge amendment led to increases in shoot and root concentrations of Cr, Cu, Ni, and Zn in plant as compared to those grown on unamended soil. Accumulation was more in roots than shoots for most of the heavy metals. Moreover, high metal removal for the harvestable parts of the crops was recorded. Sewage sludge amendment increased root and shoot length, leaves number, biomass, and antioxidant activities of sunflower. Significant increases in the activities of antioxidant enzymes and in the glutathione, proline, and soluble sugar content in response to amendment with sewage sludge may be defense mechanisms induced in response to heavy metal stress. Graphical abstract Origin, fate and behavior of sewage sludge fertilizer.

Sewage sludge pasteurization by gamma radiation: A Canadian demonstration project — 1988-91

NASA Astrophysics Data System (ADS)

Swinwood, Jean F.; Wilson, Bruce K.

Nordion International Inc. and a Canadian city, in cooperation with the Federal & Provincial Ministries of the Environment, began a project in 1988 to construct and operate a commercial-scale sewage sludge pasteurization facility using gamma radiation technology. The facility is scheduled to begin operations in 1991. This paper discusses the objectives and scope of the project, the design of the irradiation system, and the plans to market the pasteurized sludge as a high-value, organic soil conditioner and fertilizer.

Ultrasound assisted biogas production from co-digestion of wastewater sludges and agricultural wastes: Comparison with microwave pre-treatment.

PubMed

Aylin Alagöz, B; Yenigün, Orhan; Erdinçler, Ayşen

2018-01-01

This study investigates the effect of ultrasonication and microwave sludge disintegration/pre-treatment techniques on the anaerobic co-digestion efficiency of wastewater sludges with olive and grape pomaces. The effects of both co-digestion and sludge pre-treatment techniques were evaluated in terms of the organic removal efficiency and the biogas production. The "co-digestion" of wastewater sludge with both types of pomaces was revealed to be a much more efficient way for the biogas production compared to the single (mono) sludge digestion. The ultrasonication and microwave pre-treatments applied to the sludge samples caused to a further increase in biogas and methane yields. Based on applied specific energies, ultrasonication pre-treatment was found much more effective than microwave irradiation. The specific energy applied in microwave pre-treatment (87,000kj/kgTS) was almost 9 times higher than that of used in ultrasonication (10,000kj/kgTS), resulting only 10-15% increases in biogas/methane yield. Co-digestion of winery and olive industry residues with pre-treated wastewater sludges appears to be a suitable technique for waste management and energy production. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of composting strategies on the degradation of nonylphenol in sewage sludge.

PubMed

Zheng, Guodi; Chen, Tongbin; Yu, Jie; Gao, Ding; Shen, Yujun; Niu, Mingjie; Liu, Hongtao

2015-12-01

Nonylphenol can be present in sewage sludge, and this can limit the use of the sewage sludge to amend soil. Composting is one of the most efficient and economical methods of making sewage sludge stable and harmless. The nonylphenol degradation rates during composting with added bulking agents and with aeration applied were studied. Three organic bulking agents (sawdust, corn stalk, and mushroom residue) were added to sewage sludge, and the effects of the bulking agents used and the amount added on nonylphenol degradation were determined. The highest apparent nonylphenol degradation rate (71.6%) was found for sewage sludge containing 20% mushroom residue. The lowest apparent nonylphenol degradation rate (22.5%) was found for sewage sludge containing 20% sawdust. The temperature of the composting pile of sewage sludge containing 20% sawdust became too high for nonylphenol to be efficiently degraded, and the apparent nonylphenol degradation rate was lower than was found for sewage sludge containing 10% sawdust. Increasing the ventilating time from 5 to 15 min increased the apparent nonylphenol degradation rate from 19.7 to 41.6%. Using appropriate aerobic conditions facilitates the degradation of nonylphenol in sewage sludge, decreasing the risks posed by sewage sludge applied to land. Adding too much of a bulking agent can decrease the amount of the nonylphenol degraded. Increasing the ventilating time and the amount of air supplied can increase the amount of nonylphenol degraded even if doing so causes the composting pile temperature to remain low.

Lipid profiling in sewage sludge.

PubMed

Zhu, Fenfen; Wu, Xuemin; Zhao, Luyao; Liu, Xiaohui; Qi, Juanjuan; Wang, Xueying; Wang, Jiawei

2017-06-01

High value-added reutilization of sewage sludge from wastewater treatment plants (WWTPs) is essential in sustainable development in WWTPs. However, despite the advantage of high value reutilization, this process must be based on a detailed study of organics in sludge. We used the methods employed in life sciences to determine the profile of lipids (cellular lipids, free fatty acids (FFAs), and wax/gum) in five sludge samples obtained from three typical WWTPs in Beijing; these samples include one sludge sample from a primary sedimentation tank, two activated sludge samples from two Anaerobic-Anoxic-Oxic (A2/O) tanks, and two activated sludge samples from two membrane bioreactor tanks. The percentage of total raw lipids varied from 2.90% to 12.3%. Sludge from the primary sedimentation tank showed the highest concentrations of lipid, FFA, and wax/gum and the second highest concentration of cellular lipids. All activated sludge contained an abundance of cellular lipids (>54%). Cells in sludge can from plants, animals, microbes and so on in wastewater. Approximately 14 species of cellular lipids were identified, including considerable high value-potential ceramide (9567-38774 mg/kg), coenzyme (937-3897 mg/kg), and some phosphatidylcholine (75-548 mg/kg). The presence of those lipid constituents would thus require a wider range of recovery methods for sludge. Both cellular lipids and FFAs contain an abundance of C16-C18 lipids at high saturation level, and they serve as good resources for biodiesel production. Copyright © 2017 Elsevier Ltd. All rights reserved.

EMMC process for combined removal of organics, nitrogen and an odor producing substance.

PubMed

Yang, P Y; Su, R; Kim, S J

2003-12-01

In order to improve the process performance regarding the removal of organics, nitrogen, and an odor-causing compound (sulfide) contained in domestic wastewater, an entrapped-mixed-microbial cell (EMMC) with and without humic substances for both fixed and moving carrier reactors and conventional suspended growth culture (i.e. conventional activated sludge process) were investigated simultaneously. Both synthetic (simulated to the organics concentration of general domestic sewage) and actual domestic wastewater were investigated under operational conditions of 12 h of hydraulic retention time (HRT) with 1 h of aeration and 1 h of non-aeration, and 6 h of HRT with continuous aeration, at a room temperature of 25 +/- 2 degrees C. It was found that entrapping humic substances in the EMMC carriers had no impact on the removal of organics, nitrogen, and the odor-producing compound. Additionally, the performance of the EMMC moving carrier system for the removal of these pollutants is similar to that of the EMMC fixed carrier system. In general, the EMMC associated systems which provide high solids retention time achieve a better removal of chemical oxygen demand (COD), nitrogen, and the odor-producing substance than the suspended growth system for both HRTs of 6 h (continuous aeration) and 12 h (1 h of aeration and 1 h of non-aeration). Both the fixed and moving carrier EMMC processes, therefore, have the potential for improvement or replacement of the existing conventional activated sludge process with regard to improving the effluent qualities (such as COD, nitrogen and odor-producing compound) for reuse/disposal.

DWPF Simulant CPC Studies For SB8

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

Newell, J. D.

2013-09-25

Prior to processing a Sludge Batch (SB) in the Defense Waste Processing Facility (DWPF), flowsheet studies using simulants are performed. Typically, the flowsheet studies are conducted based on projected composition(s). The results from the flowsheet testing are used to 1) guide decisions during sludge batch preparation, 2) serve as a preliminary evaluation of potential processing issues, and 3) provide a basis to support the Shielded Cells qualification runs performed at the Savannah River National Laboratory (SRNL). SB8 was initially projected to be a combination of the Tank 40 heel (Sludge Batch 7b), Tank 13, Tank 12, and the Tank 51more » heel. In order to accelerate preparation of SB8, the decision was made to delay the oxalate-rich material from Tank 12 to a future sludge batch. SB8 simulant studies without Tank 12 were reported in a separate report.1 The data presented in this report will be useful when processing future sludge batches containing Tank 12. The wash endpoint target for SB8 was set at a significantly higher sodium concentration to allow acceptable glass compositions at the targeted waste loading. Four non-coupled tests were conducted using simulant representing Tank 40 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry (146% acid) SRAT testing up to 31% of the DWPF hydrogen limit. SME hydrogen generation reached 48% of of the DWPF limit for the high acid run. Two non-coupled tests were conducted using simulant representing Tank 51 at 110-146% of the Koopman Minimum Acid requirement. Hydrogen was generated during high acid stoichiometry SRAT testing up to 16% of the DWPF limit. SME hydrogen generation reached 49% of the DWPF limit for hydrogen in the SME for the high acid run. Simulant processing was successful using previously established antifoam addition strategy. Foaming during formic acid addition was not observed in any of the runs. Nitrite was destroyed in all runs and no N2O was detected during SME processing. Mercury behavior was consistent with that seen in previous SRAT runs. Mercury was stripped below the DWPF limit on 0.8 wt% for all runs. Rheology yield stress fell within or below the design basis of 1-5 Pa. The low acid Tank 40 run (106% acid stoichiometry) had the highest yield stress at 3.78 Pa.« less

Optimization of Ozonation Process for the Reduction of Excess Sludge Production from Activated Sludge Process of Sago Industry Wastewater Using Central Composite Design

PubMed Central

Subha, B.; Muthukumar, M.

2012-01-01

Sago industries effluent containing large amounts of organic content produced excess sludge which is a serious problem in wastewater treatment. In this study ozonation has been employed for the reduction of excess sludge production in activated sludge process. Central composite design is used to study the effect of ozone treatment for the reduction of excess sludge production in sago effluent and to optimise the variables such as pH, ozonation time, and retention time. ANOVA showed that the coefficient determination value (R 2) of VSS and COD reduction were 0.9689 and 0.8838, respectively. VSS reduction (81%) was achieved at acidic pH 6.9, 12 minutes ozonation, and retention time of 10 days. COD reduction (87%) was achieved at acidic pH 6.7, 8 minutes of ozonation time, and retention time of 6 days. Low ozonation time and high retention time influence maximum sludge reduction, whereas low ozonation time with low retention time was effective for COD reduction. PMID:22593666

Hydrogen sulfide formation control and microbial competition in batch anaerobic digestion of slaughterhouse wastewater sludge: Effect of initial sludge pH.

PubMed

Yan, Li; Ye, Jie; Zhang, Panyue; Xu, Dong; Wu, Yan; Liu, Jianbo; Zhang, Haibo; Fang, Wei; Wang, Bei; Zeng, Guangming

2018-07-01

High sulfur content in excess sludge impacts the production of biomethane during anaerobic digestion, meanwhile leads to hydrogen sulfide (H 2 S) formation in biogas. Effect of initial sludge pH on H 2 S formation during batch mesophilic anaerobic digestion of slaughterhouse wastewater sludge was studied in this paper. The results demonstrated that when the initial sludge pH increased from 6.5 to 8.0, the biogas production increased by 10.1%, the methane production increased by 64.1%, while the H 2 S content in biogas decreased by 44.7%. The higher initial sludge pH inhibited the competition of sulfate-reducing bacteria with methane-producing bacteria, and thus benefitted the growth of methanogens. Positive correlation was found between the relative abundance of Desulfomicrobium and H 2 S production, as well as the relative abundance of Methanosarcina and methane production. More sulfates and organic sulfur were transferred to solid and liquid rather than H 2 S formation at a high initial pH. Copyright © 2018 Elsevier Ltd. All rights reserved.

Solubilization of municipal sewage waste activated sludge by novel lytic bacterial strains.

PubMed

Lakshmi, M Veera; Merrylin, J; Kavitha, S; Kumar, S Adish; Banu, J Rajesh; Yeom, Ick-Tae

2014-02-01

Extracellular polymeric substances (EPS) are an extracellular matrix found in sludge which plays a crucial role in flocculation by interacting with the organic solids. Therefore, to enhance pretreatment of sludge, EPS have to be removed. In this study, EPS were removed with a chemical extractant, NaOH, to enhance the bacterial pretreatment. A lysozyme secreting bacterial consortium was isolated from the waste activated sludge (WAS). The result of density gradient gel electrophoresis (DGGE) analysis revealed that the isolated consortium consists of two strains. The two novel strains isolated were named as Jerish03 (NCBI accession number KC597266) and Jerish 04 (NCBI accession number KC597267) and they belong to the genus Bacillus. Pretreatment with these novel strains enhances the efficiency of the aerobic digestion of sludge. Sludge treated with the lysozyme secreting bacterial consortium produced 29 % and 28.5 % increase in suspended solids (SS) reduction and chemical oxygen demand (COD) removal compared to the raw activated sludge (without pretreatment) during aerobic digestion. It is specified that these two novel strains had a high potential to enhance WAS degradation efficiency in aerobic digestion.

Accelerating Aerobic Sludge Granulation by Adding Dry Sewage Sludge Micropowder in Sequencing Batch Reactors

PubMed Central

Li, Jun; Liu, Jun; Wang, Danjun; Chen, Tao; Ma, Ting; Wang, Zhihong; Zhuo, Weilong

2015-01-01

Micropowder (20–250 µm) made from ground dry waste sludge from a municipal sewage treatment plant was added in a sequencing batch reactor (R2), which was fed by synthetic wastewater with acetate as carbon source. Compared with the traditional SBR (R1), aerobic sludge granulation time was shortened 15 days in R2. Furthermore, filamentous bacteria in bulking sludge were controlled to accelerate aerobic granulation and form large granules. Correspondingly, the SVI decreased from 225 mL/g to 37 mL/g. X-ray Fluorescence (XRF) analysis demonstrated that Al and Si from the micropowder were accumulated in granules. A mechanism hypotheses for the acceleration of aerobic granulation by adding dry sludge micropowder is proposed: added micropowder acts as nuclei to induce bacterial attachment; dissolved matters from the micropowder increase abruptly the organic load for starved sludge to control overgrown filamentous bacteria as a framework for aggregation; increased friction from the movement of micropowder forces the filaments which extend outwards to shrink for shaping granules. PMID:26308025

Improved sustainability of feedstock production with sludge and interacting mycorrhiza.

PubMed

Seleiman, Mahmoud F; Santanen, Arja; Kleemola, Jouko; Stoddard, Frederick L; Mäkelä, Pirjo S A

2013-05-01

Recycling nutrients saves energy and improves agricultural sustainability. Sewage sludge contains 2.6% P and 3.1% N, so the availability of these nutrients was investigated using four crops grown in either soil or sand. Further attention was paid to the role of mycorrhiza in improvement of nutrient availability. The content of heavy metals and metalloids in the feedstock was analyzed. Sewage sludge application resulted in greater biomass accumulation in ryegrass than comparable single applications of either synthetic fertilizer or digested sludge. Sewage sludge application resulted in more numerous mycorrhizal spores in soil and increased root colonization in comparison to synthetic fertilizer. All plants studied had mycorrhizal colonized roots, with the highest colonization rate in maize, followed by hemp. Sewage sludge application resulted in the highest P uptake in all soil-grown plants. In conclusion, sewage sludge application increased feedstock yield, provided beneficial use for organic wastes, and contributed to the sustainability of bioenergy feedstock production systems. It also improves the soil conditions and plant nutrition through colonization by mycorrhizal fungi as well as reducing leaching and need of synthetic fertilizers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Investigation on extracellular polymeric substances, sludge flocs morphology, bound water release and dewatering performance of sewage sludge under pretreatment with modified phosphogypsum.

PubMed

Dai, Quxiu; Ma, Liping; Ren, Nanqi; Ning, Ping; Guo, Zhiying; Xie, Longgui; Gao, Haijun

2018-06-06

Modified phosphogypsum (MPG) was developed to improve dewaterability of sewage sludge, and dewatering performance, properties of treated sludge, composition and morphology distribution of EPS, dynamic analysis and multiple regression model on bound water release were investigated. The results showed that addition of MPG caused extracellular polymeric substances (EPS) disintegration through charge neutralization. Destruction of EPS promoted the formation of larger sludge flocs and the release of bound water into supernatant. Simultaneously, content of organics with molecular weight between 1000 and 7000 Da in soluble EPS (SB-EPS) increased with increasing of EPS dissolved into the liquid phase. Besides, about 8.8 kg•kg -1 DS of bound water was released after pretreatment with 40%DS MPG dosage. Additionally, a multiple linear regression model for bound water release was established, showing that lower loosely bond EPS (LB-EPS) content and specific resistance of filtration (SRF) may improve dehydration performance, and larger sludge flocs may be beneficial for sludge dewatering. Copyright © 2018 Elsevier Ltd. All rights reserved.

Membrane filtration device for studying compression of fouling layers in membrane bioreactors

PubMed Central

Bugge, Thomas Vistisen; Larsen, Poul; Nielsen, Per Halkjær; Christensen, Morten Lykkegaard

2017-01-01

A filtration devise was developed to assess compressibility of fouling layers in membrane bioreactors. The system consists of a flat sheet membrane with air scouring operated at constant transmembrane pressure to assess the influence of pressure on resistance of fouling layers. By fitting a mathematical model, three model parameters were obtained; a back transport parameter describing the kinetics of fouling layer formation, a specific fouling layer resistance, and a compressibility parameter. This stands out from other on-site filterability tests as model parameters to simulate filtration performance are obtained together with a characterization of compressibility. Tests on membrane bioreactor sludge showed high reproducibility. The methodology’s ability to assess compressibility was tested by filtrations of sludges from membrane bioreactors and conventional activated sludge wastewater treatment plants from three different sites. These proved that membrane bioreactor sludge showed higher compressibility than conventional activated sludge. In addition, detailed information on the underlying mechanisms of the difference in fouling propensity were obtained, as conventional activated sludge showed slower fouling formation, lower specific resistance and lower compressibility of fouling layers, which is explained by a higher degree of flocculation. PMID:28749990

RECAP/NEEDS FOUND FOR PATHOGENIC MICROORGANISM AND THEIR FATE ON/IN THE ENVIRONMENT

EPA Science Inventory

Federal sewage sludge regulations require for some uses of sludge on land the analyses of fecal coliforms, Salmonella sp., enteric viruses, and/or helminth ova. It is essential that the methods for analyzing these organisms be standardized and validated as quickly as possible. Se...

RESPONSE OF TALL FESCUE, BUSH BEAN, AND MAIZE TO CHROME TANNERY SLUDGE IN SOILS

EPA Science Inventory

Tannery sludge was compared with commercial nitrogen fertiliser to investigate its potential use as an alternative to commercial fertiliser. Soils containing 38% and 7% organic carbon and with nitrogen contents of 1-3% and 0-2%, respectively, were amended with either commercial N...

CONTEMPORARY PERSPECTIVES ON INFECTIOUS DISEASE AGENTS IN SEWAGE SLUDGE AND MANURE

EPA Science Inventory

The USEPA and the USDA convened a three-day Workshop on Emerging Infectious Disease Agents and Issues Associated with Sewage Sludge, Animal Manures, and Other Organic By-Products on June 4-6, 2001 in Cincinnati, Ohio. The purpose of the workshop was to review and discuss the effe...

Indicators of sewage contamination in sediments beneath a deep-ocean dump site off New York

USGS Publications Warehouse

Bothner, Michael H.; Takada, H.; Knight, I.T.; Hill, R.T.; Butman, B.; Farrington, J.W.; Colwell, R.R.; Grassle, J. F.

1994-01-01

The world's largest discharge of municipal sewage sludge to surface waters of the deep sea has caused measurable changes in the concentration of sludge indicators in sea-floor sediments, in a spatial pattern which agrees with the predictions of a recent sludge deposition model. Silver, linear alkylbenzenes, coprostanol, and spores of the bacterium Clostridium perfringens, in bottom sediments and in near-bottom suspended sediment, provide evidence for rapid settling of a portion of discharged solids, accumulation on the sea floor, and biological mixing beneath the water sediment interface. Biological effects include an increase in 1989 of two species of benthic polychaete worm not abundant at the dump site before sludge dumping began in 1986. These changes in benthic ecology are attributed to the increased deposition of utilizable food in the form of sludge-derived organic matter.

Lateral Earth Pressure at Rest and Shear Modulus Measurements on Hanford Sludge Simulants

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

Wells, Beric E.; Jenks, Jeromy WJ; Boeringa, Gregory K.

2010-09-30

This report describes the equipment, techniques, and results of lateral earth pressure at rest and shear modulus measurements on kaolin clay as well as two chemical sludge simulants. The testing was performed in support of the problem of hydrogen gas retention and release encountered in the double- shell tanks (DSTs) at the Hanford Site near Richland, Washington. Wastes from single-shell tanks (SSTs) are being transferred to double-shell tanks (DSTs) for safety reasons (some SSTs are leaking or are in danger of leaking), but the available DST space is limited.

Anaerobic co-digestion of fruit and vegetable wastes and primary sewage sludge.

PubMed

Velmurugan, B; Arathy, E C; Hemalatha, R; Philip, Jerry Elsa; Alwar Ramanujam, R

2010-01-01

Anaerobic co-digestion of fruit and vegetable wastes (FVW) and primary sewage sludge was carried out in a fed-batch reactor having a volume of 21 under ambient temperature conditions. Three different proportions (25:75, 50:50 and 75:25 in terms ofVS) of fruit and vegetable wastes and primary sewage sludge were studied for an organic loading rate (OLR) of 1.0 g VS/ l.d and with a hydraulic retention time (HRT) of 25 days. The reactor with 75% FVW and 25% sewage sludge (in terms of VS) showed better performance in terms of VS reduction and biogas yield when compared to other two proportions.

Sludge incineration in single stage combustor with gas scrubbing followed by afterburning and heat recovery

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

Albertson, O.E.; Baturay, A.

1990-04-17

This patent describes the method for disposal of waste organic sludge of the type which contains at least one certain waste material that is either a low melting eutectic that softens or heavy metal that fumes at the highest temperature required to effect incineration of the sludge and cleansing by burning of the resultant gases. It comprises: the steps of combusting the sludge in a single combustion mass overlain by a gas-filled freeboard thereby to effect burning of substantially the entire content of combustible solids while yielding wet gases which contain entrained particulates as well as combustible and non-combustible constituents,more » volatiles and condensible matter.« less

TBT and TPhT persistence in a sludged soil.

PubMed

Marcic, Christophe; Le Hecho, Isabelle; Denaix, Laurence; Lespes, Gaëtane

2006-12-01

The persistence of tributyltin (TBT) and triphenyltin (TPhT) in soils was studied, taking into consideration the quantity of sewage sludge, TBT and TPhT concentrations in soil as well as the soil pH. The organotin compounds (OTC) were introduced into the soil via a spiked urban sludge, simulating agricultural practise. OTC speciation was achieved after acidic extraction of soil samples followed by gas chromatography-pulsed flame photometric analysis (GC-PFPD). Leaching tests conducted on a spiked sludge showed that more than 98% of TBT are sorbed on the sludge. TBT persistence in soil appeared to depend on its initial concentration in sludge. Thus, it was more important when concentration is over 1000 microg(Sn) kg(-1) of sludge. More than 50% of the initial TBT added into the soil were still present after 2 months, whatever the experimental conditions. The main degradation product appeared to be dibutyltin. About 90% of TPhT were initially sorbed on sludge, whatever the spiking concentration in sludge was. However, TPhT seemed to be quantitatively exchangeable at the solid/liquid interface, according to the leaching tests. It was also significantly degraded in sludged soil as only about 20% of TPhT remain present after 2 months, the monophenyltin being the main degradation product. pH had a significant positive effect on TBT and particularly TPhT persistence, according to the initial amounts introduced into the soil. Thus, at pH over 7 and triorganotin concentration over 100 microg(Sn) kg(-1), less than 10% of TBT but about 60% of TPhT were degraded. When the sludge was moderately contaminated by triorganotins (typically 50 microg(Sn) kg(-1) in our conditions) the pH had no effect on TBT and TPhT persistence.

Virus elimination in activated sludge systems: from batch tests to mathematical modeling.

PubMed

Haun, Emma; Ulbricht, Katharina; Nogueira, Regina; Rosenwinkel, Karl-Heinz

2014-01-01

A virus tool based on Activated Sludge Model No. 3 for modeling virus elimination in activated sludge systems was developed and calibrated with the results from laboratory-scale batch tests and from measurements in a municipal wastewater treatment plant (WWTP). The somatic coliphages were used as an indicator for human pathogenic enteric viruses. The extended model was used to simulate the virus concentration in batch tests and in a municipal full-scale WWTP under steady-state and dynamic conditions. The experimental and modeling results suggest that both adsorption and inactivation processes, modeled as reversible first-order reactions, contribute to virus elimination in activated sludge systems. The model should be a useful tool to estimate the number of viruses entering water bodies from the discharge of treated effluents.

Co-hydrothermal treatment of fallen leaves with iron sludge to prepare magnetic iron product and solid fuel.

PubMed

Gu, Lin; Li, Binglian; Wen, Haifeng; Zhang, Xin; Wang, Liang; Ye, Jianfeng

2018-06-01

The hydrothermal carbonization (HTC) was performed on Metasequoia Leaves (ML) in the presence of iron sludge, both of which were generated as solid residuals. The relations between sludge, char's properties and operating conditions were systemically investigated. Iron sludge primarily catalyzed the efficient formation of char with higher heating value (HHV) becoming 1.15-1.65 times of ML (18.21 MJ/kg) and was meanwhile reduced to magnetite. The hydrated Fe ions in octahedron crystals acted as nucleophiles facilitating the dehydration and decarboxylation reactions. The increased HHV is found strong temperature dependent while prolonging the residence time is more preferable for low organic acids generation. Thermogravimetric analysis confirmed the iron sludge enhanced conversion of volatile to fixed carbon. The as-prepared solid char showed better stability after catalytic HTC treatment, having ignition temperature increased from 253 to 426 °C as compared to the char prepared without iron sludge addition. Copyright © 2018 Elsevier Ltd. All rights reserved.

Application of ATAD technology for digesting sewage sludge in small towns: Operation and costs.

PubMed

Martín, M A; Gutiérrez, M C; Dios, M; Siles, J A; Chica, A F

2018-06-01

In an economic context marked by increasing energy costs and stricter legislation regarding the landfill disposal of wastewater treatment plant (WWTP) sewage sludge, and where biomethanization is difficult to implement in small WWTPs, an efficient alternative is required to manage this polluting waste. This study shows that autothermal thermophilic aerobic digestion (ATAD) is a feasible technique for treating sewage sludge in small- and medium-sized towns. The experiments were carried out at pilot scale on a cyclical basis and in continuous mode for nine months. The main results showed an optimal hydraulic retention time of 7 days, which led to an organic matter removal of 34%. The sanitized sludge meets the microbial quality standards for agronomic application set out in the proposed European sewage sludge directive. An economic assessment for the operation of ATAD technology was carried out, showing a treatment cost of €6.5/ton for dewatered sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.

Roles of magnetite and granular activated carbon in improvement of anaerobic sludge digestion.

PubMed

Peng, Hong; Zhang, Yaobin; Tan, Dongmei; Zhao, Zhiqiang; Zhao, Huimin; Quan, Xie

2018-02-01

Granular activated carbon (GAC) or magnetite could promote methane production from organic wastes, but their roles in enhancing anaerobic sludge digestion have not been clarified. GAC, magnetite and their combination were complemented into sludge digesters, respectively. Experimental results showed that average methane production increased by 7.3% for magnetite, 13.1% for GAC, and 20% for the combination of magnetite and GAC, and the effluent TCOD of the control, magnetite, GAC and magnetite-GAC digesters on day 56 were 53.2, 49.6, 48.0 and 46.6 g/L, respectively. Scanning electron microscope (SEM), nitrogen adsorption, Fourier transform infrared spectroscopy (FTIR) and microbial analysis indicated that magnetite enriched iron-reducing bacteria responsible for sludge hydrolysis while GAC enhanced syntrophic metabolism between iron-reducing bacteria and methanogens due to its high electrical conductivity and large surface area. Supplementing magnetite and GAC together into an anaerobic digester simultaneously accelerated sludge hydrolysis and methane production, resulting in better sludge digestion performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of sludge stabilization processes and sludge origin (urban or hospital) on the mobility of pharmaceutical compounds following sludge landspreading in laboratory soil-column experiments.

PubMed

Lachassagne, Delphine; Soubrand, Marilyne; Casellas, Magali; Gonzalez-Ospina, Adriana; Dagot, Christophe

2015-11-01

This study aimed to determine the effect of sludge stabilization treatments (liming and anaerobic digestion) on the mobility of different pharmaceutical compounds in soil amended by landspreading of treated sludge from different sources (urban and hospital). The sorption and desorption potential of the following pharmaceutical compounds: carbamazepine (CBZ), ciprofloxacin (CIP), sulfamethoxazole (SMX), salicylic acid (SAL), ibuprofen (IBU), paracetamol (PAR), diclofenac (DIC), ketoprofen (KTP), econazole (ECZ), atenolol (ATN), and their solid-liquid distribution during sludge treatment (from thickening to stabilization) were investigated in the course of batch testing. The different sludge samples were then landspread at laboratory scale and leached with an artificial rain simulating 1 year of precipitation adapted to the surface area of the soil column used. The quality of the resulting leachate was investigated. Results showed that ibuprofen had the highest desorption potential for limed and digested urban and hospital sludge. Ibuprofen, salicylic acid, diclofenac, and paracetamol were the only compounds found in amended soil leachates. Moreover, the leaching potential of these compounds and therefore the risk of groundwater contamination depend mainly on the origin of the sludge because ibuprofen and diclofenac were present in the leachates of soils amended with urban sludge, whereas paracetamol and salicylic acid were found only in the leachates of soils amended with hospital sludge. Although carbamazepine, ciprofloxacin, sulfamethoxazole, ketoprofen, econazole, and atenolol were detected in some sludge, they were not present in any leachate. This reflects either an accumulation and/or (bio)degradation of these compounds (CBZ, CIP, SMX, KTP, ECZ, and ATN ), thus resulting in very low mobility in soil. Ecotoxicological risk assessment, evaluated by calculating the risk quotients for each studied pharmaceutical compound, revealed no high risk due to the application on the soil of sludge stabilized by liming or anaerobic digestion.

Bacterial communities in different locations, seasons and segments of a dairy wastewater treatment system consisting of six segments.

PubMed

Hirota, Kikue; Yokota, Yuji; Sekimura, Toru; Uchiumi, Hiroshi; Guo, Yong; Ohta, Hiroyuki; Yumoto, Isao

2016-08-01

A dairy wastewater treatment system composed of the 1st segment (no aeration) equipped with a facility for the destruction of milk fat particles, four successive aerobic treatment segments with activated sludge and a final sludge settlement segment was developed. The activated sludge is circulated through the six segments by settling sediments (activated sludge) in the 6th segment and sending the sediments beck to the 1st and 2nd segments. Microbiota was examined using samples from the non-aerated 1st and aerated 2nd segments obtained from two farms using the same system in summer or winter. Principal component analysis showed that the change in microbiota from the 1st to 2nd segments concomitant with effective wastewater treatment is affected by the concentrations of activated sludge and organic matter (biological oxygen demand [BOD]), and dissolved oxygen (DO) content. Microbiota from five segments (1st and four successive aerobic segments) in one location was also examined. Although the activated sludge is circulating throughout all the segments, microbiota fluctuation was observed. The observed successive changes in microbiota reflected the changes in the concentrations of organic matter and other physicochemical conditions (such as DO), suggesting that the microbiota is flexibly changeable depending on the environmental condition in the segments. The genera Dechloromonas, Zoogloea and Leptothrix are frequently observed in this wastewater treatment system throughout the analyses of microbiota in this study. Copyright © 2016. Published by Elsevier B.V.

Anaerobic hydrogen production with an efficient carrier-induced granular sludge bed bioreactor.

PubMed

Lee, Kuo-Shing; Wu, Ji-Fang; Lo, Yung-Sheng; Lo, Yung-Chung; Lin, Ping-Jei; Chang, Jo-Shu

2004-09-05

A novel bioreactor containing self-flocculated anaerobic granular sludge was developed for high-performance hydrogen production from sucrose-based synthetic wastewater. The reactor achieved an optimal volumetric hydrogen production rate of approximately 7.3 L/h/L (7,150 mmol/d/L) and a maximal hydrogen yield of 3.03 mol H2/mol sucrose when it was operated at a hydraulic retention time (HRT) of 0.5 h with an influent sucrose concentration of 20 g COD/L. The gas-phase hydrogen content and substrate conversion also exceeded 40 and 90%, respectively, under optimal conditions. Packing of a small quantity of carrier matrices on the bottom of the upflow reactor significantly stimulated sludge granulation that can be accomplished within 100 h. Among the four carriers examined, spherical activated carbon was the most effective inducer for granular sludge formation. The carrier-induced granular sludge bed (CIGSB) bioreactor was started up with a low HRT of 4-8 h (corresponding to an organic loading rate of 2.5-5 g COD/h/L) and enabled stable operations at an extremely low HRT (up to 0.5 h) without washout of biomass. The granular sludge was rapidly formed in CIGSB supported with activated carbon and reached a maximal concentration of 26 g/L at HRT = 0.5 h. The ability to maintain high biomass concentration at low HRT (i.e., high organic loading rate) highlights the key factor for the remarkable hydrogen production efficiency of the CIGSB processes.

Full-scale effects of addition of sludge from water treatment stations into processes of sewage treatment by conventional activated sludge.

PubMed

Luiz, Marguti André; Sidney Seckler, Ferreira Filho; Passos, Piveli Roque

2018-06-01

An emerging practice for water treatment plant (WTP) sludge is its disposal in wastewater treatment plants (WWTP), an alternative that does not require the installation of sludge treatment facilities in the WTP. This practice can cause both positive and negative impacts in the WWTP processes since the WTP sludge does not have the same characteristics as domestic wastewater. This issue gives plenty of information in laboratory and pilot scales, but lacks data from full-scale studies. The main purpose of this paper is to study the impact of disposing sludge from the Rio Grande conventional WTP into the ABC WWTP, an activated sludge process facility. Both plants are located in São Paulo, Brazil, and are full-scale facilities. The WTP volumetric flow rate (4.5 m³/s) is almost three times that of WWTP (1.6 m³/s). The data used in this study came from monitoring the processes at both plants. The WWTP liquid phase treatment analysis included the variables BOD, COD, TSS, VSS, ammonia, total nitrogen, phosphorus and iron, measured at the inlet, primary effluent, mixed liquor, and effluent. For the WWTP solids treatment, the parameters tested were total and volatile solids. The performance of the WWTP process was analyzed with and without sludge addition: 'without sludge' in years 2005 and 2006 and 'with sludge' from January 2007 to March 2008. During the second period, the WTP sludge addition increased the WWTP removal efficiencies for solids (93%-96%), organic matter (92%-94% for BOD) and phosphorus (52%-88%), when compared to the period 'without sludge'. These improvements can be explained by higher feed concentrations combined to same or lower effluent concentrations in the 'with sludge' period. No critical negative impacts occurred in the sludge treatment facilities, since the treatment units absorbed the extra solids load from the WTP sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microbial dynamics in anaerobic digestion reactors for treating organic urban residues during the start-up process.

PubMed

Alcántara-Hernández, R J; Taş, N; Carlos-Pinedo, S; Durán-Moreno, A; Falcón, L I

2017-06-01

Anaerobic digestion of organic residues offers economic benefits via biogas production, still methane (CH 4 ) yield relies on the development of a robust microbial consortia for adequate substrate degradation, among other factors. In this study, we monitor biogas production and changes in the microbial community composition in two semi-continuous stirred tank reactors during the setting process under mesophilic conditions (35°C) using a 16S rDNA high-throughput sequencing method. Reactors were initially inoculated with anaerobic granular sludge from a brewery wastewater treatment plant, and gradually fed organic urban residues (4·0 kg VS m -3  day -1 ) . The inocula and biomass samples showed changes related to adaptations of the community to urban organic wastes including a higher relative proportion of Clostridiales, with Ruminococcus spp. and Syntrophomonas spp. as recurrent species. Candidatus Cloacamonas spp. (Spirochaetes) also increased from ~2·2% in the inoculum to >10% in the reactor biomass. The new community consolidated the cellulose degradation and the propionate and amino acids fermentation processes. Acetoclastic methanogens were more abundant in the reactor, where Methanosaeta spp. was found as a key player. This study demonstrates a successful use of brewery treatment plant granular sludge to obtain a robust consortium for methane production from urban organic solid waste in Mexico. This study describes the selection of relevant bacteria and archaea in anaerobic digesters inoculated with anaerobic granular sludge from a brewery wastewater treatment plant. Generally, these sludge granules are used to inoculate reactors digesting organic urban wastes. Though, it is still not clearly understood how micro-organisms respond to substrate variations during the reactor start-up process. After feeding two reactors with organic urban residues, it was found that a broader potential for cellulose degradation was developed including Bacteroidetes, Firmicutes and Spirochaetes. These results clarify the bacterial processes behind new reactors establishment for treating organic wastes in urban areas. © 2017 The Society for Applied Microbiology.

Waste-Activated Sludge Fermentation for Polyacrylamide Biodegradation Improved by Anaerobic Hydrolysis and Key Microorganisms Involved in Biological Polyacrylamide Removal

PubMed Central

Dai, Xiaohu; Luo, Fan; Zhang, Dong; Dai, Lingling; Chen, Yinguang; Dong, Bin

2015-01-01

During the anaerobic digestion of dewatered sludge, polyacrylamide (PAM), a chemical conditioner, can usually be consumed as a carbon and nitrogen source along with other organic matter (e.g., proteins and carbohydrates in the sludge). However, a significant accumulation of acrylamide monomers (AMs) was observed during the PAM biodegradation process. To improve the anaerobic hydrolysis of PAM, especially the amide hydrolysis process, and to avoid the generation of the intermediate product AM, a new strategy is reported herein that uses an initial pH of 9, 200 mg COD/L of PAM and a fermentation time of 17 d. First, response surface methodology (RSM) was applied to optimize PAM removal in the anaerobic digestion of the sludge. The biological hydrolysis of PAM reached 86.64% under the optimal conditions obtained from the RSM. Then, the mechanisms for the optimized parameters that significantly improved the biological hydrolysis of PAM were investigated by the synergistic effect of the main organic compounds in the sludge, the floc size distribution, and the enzymatic activities. Finally, semi-continuous-flow experiments for a microbial community study were investigated based on the determination of key microorganisms involved in the biological hydrolysis of PAM. PMID:26144551

Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor

PubMed Central

Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

2015-01-01

Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3−-N could be removed or reduced, some amount of NO2−-N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy. PMID:26257096

Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor.

PubMed

Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

2015-08-10

Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3(-)-N could be removed or reduced, some amount of NO2(-)-N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy.

The carbonaceous sorbent based on the secondary silica-containing material from oil extraction industry

NASA Astrophysics Data System (ADS)

Starostina, I. V.; Stolyarov, D. V.; Anichina, Ya N.; Porozhnyuk, E. V.

2018-01-01

The object of research in this work is the silica-containing waste of oil extraction industry - the waste kieselghur (diatomite) sludge from precoat filtering units, used for the purification of vegetable oils from organic impurities. As a result of the thermal modification of the sludge, which contains up to 70% of organic impurities, a finely-dispersed low-porous carbonaceous mineral sorption material is formed. The modification of the sludge particles surface causes the substantial alteration of its physical, chemical, adsorption and structural properties - the organic matter is charred, the particle size is reduced, and on the surface of diatomite particles a carbon layer is formed, which deposits in macropores and partially occludes them. The amount of mesopores is increased, along with the specific surface of the obtained product. The optimal temperature of sludge modification is 500°C. The synthesized carbonaceous material can be used as an adsorbing agent for the purification of wastewater from heavy metal ions. The sorption capacity of Cu2+ ions amounted to 14.2 mg·g-1 and for Ni2+ ions - 17.0 mg·g-1. The obtained values exceed the sorption capacity values of the initial kieselghur, used as a filtering charge, for the researched metal ions.

Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor

NASA Astrophysics Data System (ADS)

Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

2015-08-01

Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3--N could be removed or reduced, some amount of NO2--N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy.

Stabilization of tannery sludge by co-treatment with aluminum anodizing sludge and phytotoxicity of end-products.

PubMed

Pantazopoulou, E; Zebiliadou, O; Mitrakas, M; Zouboulis, A

2017-03-01

A global demand for efficient re-utilization of produced solid wastes, which is based on the principles of re-use and recycling, results to a circular economy, where one industry's waste becomes another's raw material and it can be used in a more efficient and sustainable way. In this study, the influence of a by-product addition, such as aluminum anodizing sludge, on tannery waste (air-dried sludge) stabilization was examined. The chemical characterization of tannery waste leachate, using the EN 12457-2 standard leaching test, reveals that tannery waste cannot be accepted even in landfills for hazardous wastes, according to the EU Decision 2003/33/EC. The stabilization of tannery waste was studied applying different ratios of tannery waste and aluminum anodizing sludge, i.e. 50:50, 60:40, 70:30 and 80:20 ratios respectively. Subsequently, the stabilization rate of the qualified as optimum homogenized mixture of 50:50 ratio was also tested during time (7, 15 and 30days). Moreover, this stabilized product was subjected to phytotoxicity tests using the Lepidium sativum, Sinapis alba and Sorghum saccharatum seeds. The experimental results showed that aluminum anodizing sludge managed to stabilize effectively chromium and organic content of tannery waste, which are the most problematic parameters influencing its subsequent disposal. As a result, tannery waste stabilized with the addition of aluminum anodizing sludge at 50:50 ratio can be accepted in non-hazardous waste landfills, as chromium and dissolved organic carbon concentrations in the respective leachate are below the relevant regulation limits, while the stabilized waste shows decreased phytotoxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous enhancement of sludge dewaterability and removal of sludge-borne heavy metals through a novel oxidative leaching induced by nano-CaO2.

PubMed

Wu, Boran; Dai, Xiaohu; Chai, Xiaoli

2017-07-01

The production of sewage sludge with the presence of various contaminants has been a serious issue for the operation of wastewater treatment plants on both the economical and environmental sides. To minimize the sludge volume to be handled and limit the potential environmental risk, this study developed a novel oxidative leaching process for enhanced sewage sludge dewatering and simultaneous removal of heavy metals based on nano-CaO 2 . Response surface methodology determined the following optimal conditioning parameters in terms of capillary suction time reduction: 0.0906 g/g dry solid (DS) nano-CaO 2 , 0.9969 mmol/g DS Fe 2+ , and pH of 5.59. The speciation partitioning analysis of the heavy metals pre and post nano-CaO 2 peroxidation indicated that the content of organically bound metals decreased and the percentage of soluble fraction increased substantially, which was beneficial for the removal of heavy metals through the dewatering unit. Nano-CaO 2 peroxidation could also induce the transformation of extracellular polymeric substances (EPS) from the tightly bound layers to the loosely bound layers of sewage sludge flocs. Through the decline of the Ryan-Weber constant of fluorescence titration and the pseudo-first-order kinetic constant of complexation, it was verified that the binding capacity of EPS with metal ions could be damaged by nano-CaO 2 peroxidation, which was the primary mechanism behind the substantial reduction of organically bound metals. This study is believed to provide novel insights into the application of nanotechnology in terms of the simultaneous volume and toxicity reduction of sewage sludge. Graphical abstract.

Inhibition of Anaerobic Phosphate Release by Nitric Oxide in Activated Sludge

PubMed Central

Van Niel, E. W. J.; Appeldoorn, K. J.; Zehnder, A. J. B.; Kortstee, G. J. J.

1998-01-01

Activated sludge not containing significant numbers of denitrifying, polyphosphate [poly(P)]-accumulating bacteria was grown in a fill-and-draw system and exposed to alternating anaerobic and aerobic periods. During the aerobic period, poly(P) accumulated up to 100 mg of P · g of (dry) weight. When portions of the sludge were incubated anaerobically in the presence of acetate, 80 to 90% of the intracellular poly(P) was degraded and released as orthophosphate. Degradation of poly(P) was mainly catalyzed by the concerted action of polyphosphate:AMP phosphotransferase and adenylate kinase, resulting in ATP formation. In the presence of 0.3 mM nitric oxide (NO) in the liquid-phase release of phosphate, uptake of acetate, formation of poly-β-hydroxybutyrate, utilization of glycogen, and formation of ATP were severely inhibited or completely abolished. In cell extracts of the sludge, adenylate kinase activity was completely inhibited by 0.15 mM NO. The nature of this inhibition was probably noncompetitive, similar to that with hog adenylate kinase. Activated sludge polyphosphate glucokinase was also completely inhibited by 0.15 mM NO. It is concluded that the inhibitory effect of NO on acetate-mediated phosphate release by the sludge used in this study is due to the inhibition of adenylate kinase in the phosphate-releasing organisms. The inhibitory effect of nitrate and nitrite on phosphate release is probably due to their conversion to NO. The lack of any inhibitory effect of NO on adenylate kinase of the poly(P)-accumulating Acinetobacter johnsonii 210A suggests that this type of organism is not involved in the enhanced biological phosphate removal by the sludges used. PMID:9687452

Production of well-matured compost from night-soil sludge by an extremely short period of thermophilic composting.

PubMed

Nakasaki, Kiyohiko; Ohtaki, Akihito; Takemoto, Minoru; Fujiwara, Shunrokuro

2011-03-01

The effect of various operational conditions on the decomposition of organic material during the composting of night-soil treatment sludge was quantitatively examined. The optimum composting conditions were found to be a temperature of ca. 60°C and an initial pH value of 8. Rapid decomposition of organic matter ceased by the sixth day of composting under these optimum conditions, and the final value of the cumulative emission of carbon (E(C)), which represents the degree of organic matter decomposition, was less than 40%, indicating that the sludge contained only a small amount of easily degradable organic material. A plant growth assay using Komatsuna (Brassica campestris L. var. rapiferafroug) in a 1/5000a standard cultivation pot was then conducted for the compost at various degrees of organic matter decomposition: the raw composting material, the final compost obtained on day 6, and the 2 intermediate compost products (i.e., E(C)=10% and 20%). It was found that the larger the E(C), the greater the yield of Komatsuna growth. It was also found that 6 days of composting is sufficient to promote Komatsuna growth at the standard loading level, which is equivalent to a 1.5 g N/pot, since the promotion effect was as high as that obtained using chemical fertilizer. It can therefore be concluded that well-matured compost could be obtained in a short period of time (i.e., as early as 6 days), when night-soil sludge is composted under optimum conditions. Copyright © 2010 Elsevier Ltd. All rights reserved.

Multiple syntrophic interactions drive biohythane production from waste sludge in microbial electrolysis cells.

PubMed

Liu, Qian; Ren, Zhiyong Jason; Huang, Cong; Liu, Bingfeng; Ren, Nanqi; Xing, Defeng

2016-01-01

Biohythane is a new and high-value transportation fuel present as a mixture of biomethane and biohydrogen. It has been produced from different organic matters using anaerobic digestion. Bioenergy can be recovered from waste activated sludge through methane production during anaerobic digestion, but energy yield is often insufficient to sludge disposal. Microbial electrolysis cell (MEC) is also a promising approach for bioenergy recovery and waste sludge disposal as higher energy efficiency and biogas production. The systematic understanding of microbial interactions and biohythane production in MEC is still limited. Here, we report biohythane production from waste sludge in biocathode microbial electrolysis cells and reveal syntrophic interactions in microbial communities based on high-throughput sequencing and quantitative PCR targeting 16S rRNA gene. The alkali-pretreated sludge fed MECs (AS-MEC) showed the highest biohythane production rate of 0.148 L·L(-1)-reactor·day(-1), which is 40 and 80 % higher than raw sludge fed MECs (RS-MEC) and anaerobic digestion (open circuit MEC, RS-OCMEC). Current density, metabolite profiles, and hydrogen-methane ratio results all confirm that alkali-pretreatment and microbial electrolysis greatly enhanced sludge hydrolysis and biohythane production. Illumina Miseq sequencing of 16S rRNA gene amplicons indicates that anode biofilm was dominated by exoelectrogenic Geobacter, fermentative bacteria and hydrogen-producing bacteria in the AS-MEC. The cathode biofilm was dominated by fermentative Clostridium. The dominant archaeal populations on the cathodes of AS-MEC and RS-MEC were affiliated with hydrogenotrophic Methanobacterium (98 %, relative abundance) and Methanocorpusculum (77 %), respectively. Multiple pathways of gas production were observed in the same MEC reactor, including fermentative and electrolytic H2 production, as well as hydrogenotrophic methanogenesis and electromethanogenesis. Real-time quantitative PCR analyses showed that higher amount of methanogens were enriched in AS-MEC than that in RS-MEC and RS-OCMEC, suggesting that alkali-pretreated sludge and MEC facilitated hydrogenotrophic methanogen enrichment. This study proves for the first time that biohythane could be produced directly in biocathode MECs using waste sludge. MEC and alkali-pretreatment accelerated enrichment of hydrogenotrophic methanogen and hydrolysis of waste sludge. The results indicate syntrophic interactions among fermentative bacteria, exoelectrogenic bacteria and methanogenic archaea in MECs are critical for highly efficient conversion of complex organics into biohythane, demonstrating that MECs can be more competitive than conventional anaerobic digestion for biohythane production using carbohydrate-deficient substrates. Biohythane production from waste sludge by MEC provides a promising new way for practical application of microbial electrochemical technology.

Enhanced micropollutant biodegradation and assessment of nitrous oxide concentration reduction in wastewater treated by acclimatized sludge bioaugmentation.

PubMed

Boonnorat, Jarungwit; Techkarnjanaruk, Somkiet; Honda, Ryo; Ghimire, Anish; Angthong, Sivakorn; Rojviroon, Thammasak; Phanwilai, Supaporn

2018-05-11

This research investigated the micropollutant biodegradation and nitrous oxide (N 2 O) concentration reduction in high strength wastewater treated by two-stage activated sludge (AS) systems with (bioaugmented) and without (non-bioaugmented) acclimatized sludge bioaugmentation. The bioaugmented and non-bioaugmented systems were operated in parallel for 228 days, with three levels of concentrations of organics, nitrogen, and micropollutants in the influent: conditions 1 (low), 2 (moderate), and 3 (high). The results showed that, under condition 1, both systems efficiently removed the organic and nitrogen compounds. However, the bioaugmented system was more effective in the micropollutant biodegradation and N 2 O concentration reduction than the non-bioaugmented one. Under condition 2, the nitrogen and micropollutant biodegradation efficiency of the non-bioaugmented system slightly decreased, while the N 2 O concentration declined in the bioaugmented system. Under condition 3, the treatment performance and N 2 O concentration abatement were substantially lowered as the compounds concentration increased. Further analysis also showed that the acclimatized sludge bioaugmentation increased the bacterial diversity in the system. In essence, the acclimatized sludge bioaugmentation strategy was highly effective for the influent with low compounds concentration, achieving the organics and nitrogen removal efficiencies of 92-97%, relative to 71-97% of the non-bioaugmented system. The micropollutant treatment efficiency of the bioaugmented system under condition 1 was 75-92%, indicating significant improvement in the treatment performance (p < 0.05), compared with 60-79% of the non-bioaugmented system. Copyright © 2018 Elsevier B.V. All rights reserved.

The effect of landfill leachate composition on organics and nitrogen removal in an activated sludge system with bentonite additive.

PubMed

Wiszniowski, J; Surmacz-Górska, J; Robert, D; Weber, J-V

2007-10-01

A pre-denitrification activated sludge system (AS) without internal recycle was used in lab-scale studies of landfill leachate treatment. A bentonite supplement at a ratio of 1:4 (mineral : biomass) was used to ensure high sludge settling levels and to serve as a micro-organisms carrier. The system was operated within different parameters such as hydraulic retention time (HRT), ammonia loading rate (ALR) or external recycle ratio, which was adapted to treat varying leachate concentrations of COD and ammonia, ranging from 1020 to 2680 mgO(2)l(-1) and 400-890 mgNH(4)-Nl(-1) respectively. The nitrification was complete and ammonia oxidation reached 99%; this was obtained while the ALR did not exceed 0.09 g NH(4)(+)-Ng(-1)MLVSS d(-1) and HRT was not lower than 1 day (in the aeration reactor). The performance of denitrification was successfully improved by controlling the external recycle rate, when the BOD(5)/N ratio in the raw leachate was 4.1. Consequently, N-removal of up to 80% was achieved. A 10-fold decrease in the denitrification rate was obtained at a BOD(5)/N ratio of 0.5. The efficiency of COD removal varied significantly from 36% to 84%. The positive effect of bentonite addition was determined and is discussed based on preliminary studies. The experiments were carried out in fill-and-draw activated sludge with bentonite; the biomass ratio was 1:2. The activated sludge with bentonite was fed with a synthetic high ammonia and organic-free medium.

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.

Extracellular polymeric substances (EPS) producing bacterial strains of municipal wastewater sludge: isolation, molecular identification, EPS characterization and performance for sludge settling and dewatering.

PubMed

Bala Subramanian, S; Yan, S; Tyagi, R D; Surampalli, R Y

2010-04-01

Wastewater treatment plants often face the problems of sludge settling mainly due to sludge bulking. Generally, synthetic organic polymer and/or inorganic coagulants (ferric chloride, alum and quick lime) are used for sludge settling. These chemicals are very expensive and further pollute the environment. Whereas, the bioflocculants are environment friendly and may be used to flocculate the sludge. Extracellular polymeric substances (EPS) produced by sludge microorganisms play a definite role in sludge flocculation. In this study, 25 EPS producing strains were isolated from municipal wastewater treatment plant. Microorganisms were selected based on EPS production properties on solid agar medium. Three types of EPS (slime, capsular and bacterial broth mixture of both slime and capsular) were harvested and their characteristics were studied. EPS concentration (dry weight), viscosity and their charge (using a Zetaphoremeter) were also measured. Bioflocculability of obtained EPS was evaluated by measuring the kaolin clay flocculation activity. Six bacterial strains (BS2, BS8, BS9, BS11, BS15 and BS25) were selected based on the kaolin clay flocculation. The slime EPS was better for bioflocculation than capsular EPS and bacterial broth. Therefore, extracted slime EPS (partially purified) from six bacterial strains was studied in terms of sludge settling [sludge volume index (SVI)] and dewatering [capillary suction time (CST)]. Biopolymers produced by individual strains substantially improved dewaterability. The extracted slime EPS from six different strains were partially characterized. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Farmers' attitude toward treated sludge use in the villages of West Bank, Palestine.

PubMed

Rashid, Md M; Kattou'a, Mary G; Al-Khatib, Issam A; Sato, Chikashi

2017-07-01

An application of treated sewage sludge on agricultural land has been widely accepted, as this method is simple and economical for disposal of wastewater residues. When applied properly on an agricultural land, sludge can replenish organic matter and nutrients in soil. Although sewage sludge has been used in agriculture in many parts of the world, its acceptability varies with different cultures and beliefs among farmers. Farmers' concerns on sludge use are primarily due to its anthropogenic origin, pollutants that it carries, a general perception of sewage being dirty, and its offensive odor. This paper aims to investigate farmers' perceptions on land application of treated sewage sludge on their farm. This study targeted two farming communities, namely, Anza and Beit Dajan villages, located in Jenin and Nablus districts in the West Bank, Palestine. In this study, a sample of 106 farmers were randomly selected and surveyed through a mixture of structured and open-ended questions. Results indicated that, overall, farmers have positive perceptions on land application of sludge. A majority of the farmers are in favor of the concept of sludge use when a planned wastewater treatment plant is constructed and it becomes operational. Results also indicate that a majority of the farmers are in favor of using sludge for fertilizing fruit trees, rather than growing vegetables and other plants in a greenhouse, and that many of them have knowledge of sludge properties and advantages and disadvantages of sludge use in agriculture. Despite the positive perceptions by the majority of farmers, a small fraction of the farmers are in disfavor of the use of sludge for the following reasons: psychological and social concerns, potential health risks, and their religious beliefs. Results further suggest that the land application of treated sewage sludge can be accepted by more farmers if the consumers are willing to buy agricultural products fertilized by sludge, sludge meets the public health requirements, and sludge is available at low costs. To improve farmers' perceptions on the land application of sludge, several measures are recommended.

Sludge dewatering and stabilization in drying reed beds: characterization of three full-scale systems in Catalonia, Spain.

PubMed

Uggetti, Enrica; Llorens, Esther; Pedescoll, Anna; Ferrer, Ivet; Castellnou, Roger; García, Joan

2009-09-01

Optimization of sludge management can help reducing sludge handling costs in wastewater treatment plants. Sludge drying reed beds appear as a new and alternative technology which has low energy requirements, reduced operating and maintenance costs, and causes little environmental impact. The objective of this work was to evaluate the efficiency of three full-scale drying reed beds in terms of sludge dewatering, stabilization and hygienisation. Samples of influent sludge and sludge accumulated in the reed beds were analysed for pH, Electrical Conductivity, Total Solids (TS), Volatile Solids (VS), Chemical Oxygen Demand, Biochemical Oxygen Demand, nutrients (Total Kjeldahl Nitrogen (TKN) and Total Phosphorus (TP)), heavy metals and faecal bacteria indicators (Escherichiacoli and Salmonella spp.). Lixiviate samples were also collected. There was a systematic increase in the TS concentration from 1-3% in the influent to 20-30% in the beds, which fits in the range obtained with conventional dewatering technologies. Progressive organic matter removal and sludge stabilization in the beds was also observed (VS concentration decreased from 52-67% TS in the influent to 31-49% TS in the beds). Concentration of nutrients of the sludge accumulated in the beds was quite low (TKN 2-7% TS and TP 0.04-0.7% TS), and heavy metals remained below law threshold concentrations. Salmonella spp. was not detected in any of the samples, while E. coli concentration was generally lower than 460MPN/g in the sludge accumulated in the beds. The studied systems demonstrated a good efficiency for sludge dewatering and stabilization in the context of small remote wastewater treatment plants.

Characterization of oily sludge from a Tehran oil refinery.

PubMed

Heidarzadeh, Nima; Gitipour, Saeid; Abdoli, Mohammad Ali

2010-10-01

In this study, oily sludge samples generated from a Tehran oil refinery (Pond I) were evaluated for their contamination levels and to propose an adequate remediation technique for the wastes. A simple, random, sampling method was used to collect the samples. The samples were analyzed to measure Total petroleum hydrocarbon (TPH), polyaromatic hydrocarbon (PAH) and heavy metal concentrations in the sludge. Statistical analysis showed that seven samples were adequate to assess the sludge with respect to TPH analyses. The mean concentration of TPHs in the samples was 265,600 mg kg⁻¹. A composite sample prepared from a mix of the seven samples was used to determine the sludge's additional characteristics. Composite sample analysis showed that there were no detectable amounts of PAHs in the sludge. In addition, mean concentrations of the selected heavy metals Ni, Pb, Cd and Zn were 2700, 850, 100, 6100 mg kg⁻¹, respectively. To assess the sludge contamination level, the results from the analysis above were compared with soil clean-up levels. Due to a lack of national standards for soil clean-up levels in Iran, sludge pollutant concentrations were compared with standards set in developed countries. According to these standards, the sludge was highly polluted with petroleum hydrocarbons. The results indicated that incineration, biological treatment and solidification/stabilization treatments would be the most appropriate methods for treatment of the sludges. In the case of solidification/stabilization, due to the high organic content of the sludge, it is recommended to use organophilic clays prior to treatment of the wastes.

Long-Term Impact of Field Applications of Sewage Sludge on Soil Antibiotic Resistome.

PubMed

Xie, Wan-Ying; McGrath, Steve P; Su, Jian-Qiang; Hirsch, Penny R; Clark, Ian M; Shen, Qirong; Zhu, Yong-Guan; Zhao, Fang-Jie

2016-12-06

Land applications of municipal sewage sludge may pose a risk of introducing antibiotic resistance genes (ARGs) from urban environments into agricultural systems. However, how the sewage sludge recycling and application method influence soil resistome and mobile genetic elements (MGEs) remains unclear. In the present study, high through-put quantitative PCR was conducted on the resistome of soils from a field experiment with past (between 1994 and 1997) and annual (since 1994) applications of five different sewage sludges. Total inputs of organic carbon were similar between the two modes of sludge applications. Intrinsic soil resistome, defined as the ARGs shared by the soils in the control and sludge-amended plots, consisted of genes conferring resistance to multidrug, β-lactam, Macrolide-Lincosamide-Streptogramin B (MLSB), tetracycline, vancomycin, and aminoglycoside, with multidrug resistance genes as the most abundant members. There was a strong correlation between the abundance of ARGs and MGE marker genes in soils. The composition and diversity of ARGs in the five sludges were substantially different from those in soils. Considerable proportions of ARGs and MGE marker genes in the sludges attenuated following the application, especially aminoglycoside and tetracycline resistance genes. Annual applications posed a more significant impact on the soil resistome, through both continued introduction and stimulation of the soil intrinsic ARGs. In addition, direct introduction of sludge-specific ARGs into soil was observed especially from ARG-rich sludge. These results provide a better insight into the characteristics of ARG dissemination from urban environment to the agricultural system through sewage sludge applications.

Stabilization of industry sludge by composting for use as an organic fertilizer

NASA Astrophysics Data System (ADS)

Elia Ruda, Ester; Mercedes Ocampo, Ester; Acosta, Adriana; Mongiello, Adriana; Olmos, Graciela

2013-04-01

The effluent treatment plant having PBLEINER SA food industry produces sludge coming from aerobic treatment reactors. The research team FIQ-UNL evaluated the feasibility of their use for the production of organic fertilizers as part of an environmental management problem to reduce the volume of sludge to be moved to land farming located more than 300 km of the plant. The mean values of the variables analyzed in the sludge were the following: carbon: 23.7 %, nitrogen: 7.83 %, pH: 7.36, bulk density: 0.722 g.cm-3, actual density: 1.76 g.cm-3, porosity: 50.7 %, potassium: 0.242 %, phosphorus: 1.29 %, calcium: 1.84 %, magnesium: 0.364 % and electrical conductivity: 3.51 dS.m-1 (25 °C). The content of heavy metals in sludge is much lower than the limits set by the European Union, USEPA and SENASA for use in agriculture. The mean values of the metals analyzed in the sludge were the following: cadmium: no detected, lead: 18.7 mg.kg-1, zinc 213 mg.kg-1, copper: 40.7 mg.kg-1, nickel: 110 mg.kg-1, chrome: 406 mg.kg-1, mercury: 1.53 mg.kg-1. In this framework it was proposed stabilization of sludge by composting, using sawdust or chips as stabilizing material, with aeration technique in rows with frequent turning and recycling leachate, so as to degrade organic solids humic material for application as a soil conditioner, this is for transformation into a new product to be used as fertilizer. The company provided the physical space and technical staff to assist the research team. This process design is a proposal to improve the waste treatment of an industrial plant, reducing its environmental impact and enabling the use of the resulting product for soil enhancement in the region. Optimizing operating parameters such as kinetics, moisture, temperature, pH, total dissolved solids, nutrient availability, alternative sources of carbon and processing steps, will allow obtaining technical data for the modelling process.

Hot-isostatically pressed wasteforms for Magnox sludge immobilisation

NASA Astrophysics Data System (ADS)

Heath, Paul G.; Stewart, Martin W. A.; Moricca, Sam; Hyatt, Neil C.

2018-02-01

Thermal treatment technologies offer many potential benefits for the treatment of radioactive wastes including the passivation of reactive species and significant waste volume reductions. This paper presents a study investigating the production of wasteforms using Hot-isostatic pressing technology for the immobilisation of Magnox sludges from the UK's Sellafield Site. Simulants considered physically representative of these sludges were used to determine possible processing parameters and to determine the phase assemblages and morphologies produced during processing. The study showed hot-isostatic pressing is capable of processing Magnox sludges at up to 60 wt% (oxide basis) into dense, mixed ceramic wasteforms. The wasteforms produced are a glass-bonded ceramic of mixed magnesium titanates, encapsulating localised grains of periclase. The ability to co-process Magnox sludges with SIXEP sand/clinoptilolite slurries has also been demonstrated. The importance of these results is presented through a comparison of volume reduction data, which shows HIPing may provide a 20-fold volume reduction over the current cementitious baseline and double the volume reduction attainable for vitrification technologies.

Ozonation of return activated sludge for disintegration and solubilisation with synthesized titanium oxide as catalyst

NASA Astrophysics Data System (ADS)

Sarif, S. F. Z. Mohd; Alias, S. S.; Ridwan, F. Muhammad; Salim, K. S. Ku; Abidin, C. Z. A.; Ali, U. F. Md.

2018-03-01

Ozonation of activated sludge in the present of titanium dioxide (TiO2) as catalyst to enhance the production of hydroxyl radical was evaluated in comparison to the sole ozonation process. In this process, the catalytic ozontion showed improvement in increasing ozone consumption and improving activated sludge disintegration and solubilisation. The reduction of total suspended solid (TSS), volatile suspended solid (VSS) and soluble chemical oxygen demand (SCOD) solubilisation was better in the catalytic ozonation system. Initial pH 7 of activated sludge was found best to disintegrate and solubilise the sludge flocs. However upon additional of sodium hydroxide (NaOH) in pH adjustment enhanced the solubilisation of organic matter from the flocs and cells, making the initial pH 9 is the best condition for activated sludge solubilisation. Yet the initial pH 7 of activated sludge supernatant was the best condition to achieve SCOD solubilisation due to sludge floc disintegration, when it had stronger correlation between TSS reduction and SCOD solubilisation (R2=0.961). Lower amount of catalyst of 100 mgTiO2/gTSS was found to disintegrate and solubilise the activated sludge better with 30.4% TSS reduction and 25.2% SCOD solubilisation efficiency, compared to 200 mgTiO2/gTSS with 21.9% and 17.1% TSS reduction and SCOD solubilisation, respectively.

Occurrence of hexabromocyclododecane (HBCD) in sewage sludge from Shanghai: implications for source and environmental burden.

PubMed

Xiang, Nan; Chen, Ling; Meng, Xiang-Zhou; Dai, Xiaohu

2015-01-01

Sewage sludge is regarded as one important sink for hydrophobic pollutants, including hexabromocyclododecane (HBCD), but the current pollution situation of HBCD in sludge from China is unknown, despite that many studies have reported its occurrence in other environmental compartments across China. In this study, we collected 27 sludge samples from Shanghai to investigate the occurrence and distribution, to examine the diastereoisomer profile and sources, and to provide advice for future pollution control. HBCD is ubiquitous in sludge with a mean concentration of 4.7ngg(-1) dry weight (dw) (range: 0.10-37.2ngg(-1) dw), lower than data from European countries and the United States. Sludge from wastewater treatment plants (WWTPs) treating industrial wastewater contained high levels of HBCD. However, no significant relationships were found between HBCD and four parameters (total organic carbon, the percentage of industrial wastewater, capacity and sludge production of WWTPs). α- and γ-HBCD were two main components with the corresponding contributions of 47.9% and 48.0%. Comparing with the annual production of HBCD in China, its storage in sewage sludge is extremely low (less than 0.002%), indicating future release of HBCD from waste polystyrene foam will be significant, and careful considerations should be taken during waste disposal. To our knowledge, this is the first report on HBCD in sewage sludge from China. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of stabilization and sludge properties in a combined process of anaerobic digestion and thermophilic aerobic digestion.

PubMed

Cheng, Jiehong; Kong, Feng; Zhu, Jun; Wu, Xiao

2015-01-01

A novel process of combining mesophilic (<35°C) anaerobic digestion with the thermophilic (55°C) aerobic digestion process (AN-TAD) was designed to stabilize sludge and economize aeration energy. Effects of stabilization and sludge properties for AN-TAD process were evaluated by batch experiments during a 25 d digestion period. The sludges digested by AN-TAD process achieved the requirements for Class-A sludge standard. The sludge at total solid (TS) 5.4% had the highest value of decay coefficient K(d(55)) at 0.1851 d(-1) among the three TS contents according to the first-order kinetics equation. Oxidation reduction potential at below 0 mV remained for sludges at TSs of 6.5%, 5.4%, and 4.6% for at least 15 d because of initial hydrolytic-acidification. Concentrations of nitrogen and phosphorus in sludges at TSs of 6.5%, 5.4%, and 4.6% gradually increased up to the highest values in the supernatant during the initial 13 d, causing low utilized value in land application as a fertilizer. Prolonging the retention time for more than 15 d was considered because soluble phosphorus precipitated in the solid phase. High content of soluble organic matters of the soluble chemical oxygen demand, protein, and polysaccharide in the supernatant caused deterioration in sludge dewaterability rates.

Enhancement of waste activated sludge dewaterability using calcium peroxide pre-oxidation and chemical re-flocculation.

PubMed

Chen, Zhan; Zhang, Weijun; Wang, Dongsheng; Ma, Teng; Bai, Runying; Yu, Dezhong

2016-10-15

The effects of combined calcium peroxide (CaO2) oxidation with chemical re-flocculation on dewatering performance and physicochemical properties of waste activated sludge was investigated in this study. The evolutions of extracellular polymeric substances (EPS) distribution, composition and morphological properties were analyzed to unravel the sludge conditioning mechanism. It was found that sludge filtration performance was enhanced by calcium peroxide oxidation with the optimal dosage of 20 mg/gTSS. However, this enhancement was not observed at lower dosages due to the absence of oxidation and the performance deteriorated at higher dosages because of the release of excess EPS, mainly as protein-like substances. The variation in soluble EPS (SEPS) component can be fitted well with pseudo-zero-order kinetic model under CaO2 treatment. At the same time, extractable EPS content (SEPS and loosely bound EPS (LB-EPS)) were dramatically increased, indicating sludge flocs were effectively broken and their structure became looser after CaO2 addition. The sludge floc structure was reconstructed and sludge dewaterability was significantly enhanced using chemical re-flocculation (polyaluminium chloride (PACl), ferric iron (FeCl3) and polyacrylamide (PAM)). The inorganic coagulants performed better in improving sludge filtration dewatering performance and reducing cake moisture content than organic polymer, since they could act as skeleton builders and decrease the sludge compressibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

Co-composting as an oxygen stabilization of an organic fraction of municipal solid waste and industrial sewage sludge.

PubMed

Milczarek, M; Neczaj, E; Parkitna, K

2013-01-01

The purpose of this work is to study the characteristics of the co-composting of municipal solid waste (MSW), sewage sludge, grass and sawdust. Differing proportions of biodegradable waste were investigated through changes of temperature, oxygen consumption, organic matters, moisture content, carbon, nitrogen, C/N ratio as well as heavy metals and pathogen microorganisms content. The present study has shown that addition of MSW above 10% had a negative impact on the composting process. The initial C/N of the mixtures with a higher MSW content was below 18. Lower losses of organic matter occurred during composting for the mixture with the highest addition of MSW. Although studies have shown that composting is a good method for the disposal of organic waste additional research is required in order to optimize the organic and nitrogen compounds degradation during the co-composting process. In conclusion, a 1:4:4:1 mixture of MSW:sewage sludge:grass:sawdust is recommended because it can achieve high temperature as well as the highest organic matter degradation and highest N content in the final composting product. The concentration of heavy and light metals in all composts was within the limits of regulation of the Polish Minister of Agriculture and Rural Development.

Inhibition Of Washed Sludge With Sodium Nitrite

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

Congdon, J. W.; Lozier, J. S.

2012-09-25

This report describes the results of electrochemical tests used to determine the relationship between the concentration of the aggressive anions in washed sludge and the minimum effective inhibitor concentration. Sodium nitrate was added as the inhibitor because of its compatibility with the DWPF process. A minimum of 0.05M nitrite is required to inhibit the washed sludge simulant solution used in this study. When the worst case compositions and safety margins are considered, it is expected that a minimum operating limit of nearly 0.1M nitrite will be specified. The validity of this limit is dependent on the accuracy of the concentrationsmore » and solubility splits previously reported. Sodium nitrite additions to obtain 0.1M nitrite concentrations in washed sludge will necessitate the additional washing of washed precipitate in order to decrease its sodium nitrite inhibitor requirements sufficiently to remain below the sodium limits in the feed to the DWPF. Nitrite will be the controlling anion in "fresh" washed sludge unless the soluble chloride concentration is about ten times higher than predicted by the solubility splits. Inhibition of "aged" washed sludge will not be a problem unless significant chloride dissolution occurs during storage. It will be very important tomonitor the composition of washed sludge during processing and storage.« less

CFD Modelling Applied to the Co-Combustion of Paper Sludge and Coal in a 130 t/h CFB Boiler

NASA Astrophysics Data System (ADS)

Yu, Z. S.; Ma, X. Q.; Lai, Z. Y.; Xiao, H. M.

Three-dimensional mathematical model has been developed as a tool for co-combustion of paper sludge and coal in a 130 tJh Circulating Fluidized Bed (CFB) boiler. Mathematical methods had been used based on a commercial software FLUENT for combustion. The predicted results of CFB furnace show that the co-combustion of paper sludge/coal is initially intensively at the bottom of bed; the temperature reaches its maximum in the dense-phase zone, around l400K. It indicates that paper sludge spout into furnace from the recycle inlet can increase the furnace maximum temperature (l396.3K), area-weighted average temperature (l109.6K) and the furnace gas outlet area-weighted average temperature(996.8K).The mathematical modeling also predicts that 15 mass% paper sludge co-combustion is the highest temperature at the flue gas outlet, it is 1000.8K. Moreover, it is proved that mathematical models can serve as a tool for detailed analysis of co-combustion of paper sludge and coal processes in a circulating fluidized bed furnace when in view of its convenience. The results gained from numerical simulation show that paper sludge enter into furnace from the recycle inlet excelled than mixing with coal and at the underside of phase interface.

Example study for granular bioreactor stratification: Three-dimensional evaluation of a sulfate-reducing granular bioreactor

PubMed Central

Hao, Tian-wei; Luo, Jing-hai; Su, Kui-zu; Wei, Li; Mackey, Hamish R.; Chi, Kun; Chen, Guang-Hao

2016-01-01

Recently, sulfate-reducing granular sludge has been developed for application in sulfate-laden water and wastewater treatment. However, little is known about biomass stratification and its effects on the bioprocesses inside the granular bioreactor. A comprehensive investigation followed by a verification trial was therefore conducted in the present work. The investigation focused on the performance of each sludge layer, the internal hydrodynamics and microbial community structures along the height of the reactor. The reactor substratum (the section below baffle 1) was identified as the main acidification zone based on microbial analysis and reactor performance. Two baffle installations increased mixing intensity but at the same time introduced dead zones. Computational fluid dynamics simulation was employed to visualize the internal hydrodynamics. The 16S rRNA gene of the organisms further revealed that more diverse communities of sulfate-reducing bacteria (SRB) and acidogens were detected in the reactor substratum than in the superstratum (the section above baffle 1). The findings of this study shed light on biomass stratification in an SRB granular bioreactor to aid in the design and optimization of such reactors. PMID:27539264

Evaluation of Municipal Wastewater Treatment Plant Activated Sludge for Biodegradation of Propylene Glycol as an Aircraft Deicing Fluid

DTIC Science & Technology

2012-03-01

Propylene Glycol Deicer Biodegredation Kinetics: Complete-Mix Stirred Tank Reactors , Filter, and Fluidized Bed . Journal of Environmental...scale sequencing batch reactor containing municipal waste water treatment facility activated sludge (AS) performing simultaneous organic carbon...Sequencing Batch Reactor Operation ..................................................................... 13 PG extraction from AS

Water Utility Lime Sludge Reuse – An Environmental Sorbent for Power Utilities

EPA Science Inventory

Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up ...

Microscopic Analysis of Plankton, Periphyton, and Activated Sludge. Training Manual.

ERIC Educational Resources Information Center

Environmental Protection Agency, Washington, DC. Office of Water Programs.

This manual is intended for professional personnel in the fields of water pollution control, limnology, water supply and waste treatment. Primary emphasis is given to practice in the identification and enumeration of microscopic organisms which may be encountered in water and activated sludge. Methods for the chemical and instrumental evaluation…

Wastewater and Sludge Nutrient Utilization in Forest Ecosystems

Treesearch

D.G. Brockway; D.H. Urie; P.V. Nguyen; J.B. Hart

1986-01-01

Although forest ecosystems have evolved efficient mechanisms to assimilate and retain modest levels of annual geochemical input, their productivity is frequently limited by low levels of available nutrients. A review of research studies conducted in the major U.S. forest regions indicates that the nutrients and organic matter in wastewater and sludge representa...

HIGHLIGHTS, INSIGHTS, AND PERSPECTIVES ON INFECTIOUS DISEASE AGENTS IN SEWAGE SLUDGE AND ANIMAL MANURE IN THE U.S.

EPA Science Inventory

The purpose of this chapter is: 1) Highlight the core principles and findings from the Workshop on Emerging Infectious Disease Agents and Issues Associated With Sewage Sludge, Animal Manures and Other Organic By-Products held June 4-6, 2001, Cincinnati, Ohio, so that all readers,...

Characterization of microbial communities in heavy crude oil from Saudi Arabia.

PubMed

Albokari, Majed; Mashhour, Ibrahim; Alshehri, Mohammed; Boothman, Chris; Al-Enezi, Mousa

The complete mineralization of crude oil into carbon dioxide, water, inorganic compounds and cellular constituents can be carried out as part of a bioremediation strategy. This involves the transformation of complex organic contaminants into simpler organic compounds by microbial communities, mainly bacteria. A crude oil sample and an oil sludge sample were obtained from Saudi ARAMCO Oil Company and investigated to identify the microbial communities present using PCR-based culture-independent techniques. In total, analysis of 177 clones yielded 30 distinct bacterial sequences. Clone library analysis of the oil sample was found to contain Bacillus , Clostridia and Gammaproteobacteria species while the sludge sample revealed the presence of members of the Alphaproteobacteria , Betaproteobacteria , Gammaproteobacteria , Clostridia , Spingobacteria and Flavobacteria . The dominant bacterial class identified in oil and sludge samples was found to be Bacilli and Flavobacteria , respectively. Phylogenetic analysis showed that the dominant bacterium in the oil sample has the closest sequence identity to Enterococcus aquimarinus and the dominant bacterium in the sludge sample is most closely related to the uncultured Bacteroidetes bacterium designated AH.KK.

The biodrying concept: an innovative technology creating energy from sewage sludge.

PubMed

Winkler, M-K H; Bennenbroek, M H; Horstink, F H; van Loosdrecht, M C M; van de Pol, G-J

2013-11-01

A full-scale biodrying installation was treating 150 kton (wet weight) of dewatered waste activated sludge per year. The waste was treated at thermophilic conditions (65-75 °C) in a 2-step forced aeration process reducing the total wet sludge weight by 73%. The final product had a high caloric value (7700-10,400 (kJ/kg)), allowing a combustion for energy generation in external facilities. The resulting product met the European microbial and heavy metal quality standards needed for an application as organic fertilizer. The facility used <0.5 MW of electricity and recovered 9.3 MW from biologically produced heat, which was internally used for the heating of office buildings. Produced ammonia, originating from the microbial conversion of organic matter, was recovered from the ventilated air in an acid gas scrubber as an ammonium sulphate solution 40% (w/w) (7.3 kton/year) and was sold as substitute for artificial fertilizers. The sustainability of this process is discussed relative to other sludge handling processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Application of sewage sludge and intermittent aeration strategy to the bioremediation of DDT- and HCH-contaminated soil.

PubMed

Liang, Qi; Lei, Mei; Chen, Tongbin; Yang, Jun; Wan, Xiaoming; Yang, Sucai

2014-08-01

Adding organic amendments to stimulate the biodegradation of pesticides is a subject of ongoing interest. The effect of sewage sludge on the bioremediation of dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH) contaminated soil was investigated in bench scale experiments, and intermittent aeration strategy was also used in this study to form an anaerobic-aerobic cycle. Bioremediation of DDT and HCH was enhanced with the addition of sewage sludge and the intermittent aeration. The removal rates of HCH and DDT were raised by 16.8%-80.8% in 10 days. Sewage sludge increased the organic carbon content from 6.2 to 218 g/kg, and it could also introduce efficient degradation microbes to soil, including Pseudomonas sp., Bacillus sp. and Sphingomonas sp. The unaerated phase enhanced the anaerobic dechlorination of DDT and HCH, and anaerobic removal rates of β-HCH, o,p'-DDT and p,p'-DDT accounted for more than 50% of the total removal rates, but the content of α-HCH declined more in the aerobic phase. Copyright © 2014. Published by Elsevier B.V.

Bacterial community dynamics in long-term operation of a pilot plant using aerobic granular sludge to treat pig slurry.

PubMed

Fra-Vázquez, A; Morales, N; Figueroa, M; Val Del Río, A; Regueiro, L; Campos, J L; Mosquera-Corral, A

2016-09-01

Aerobic granular sludge represents an interesting approach for simultaneous organic matter and nitrogen removal in wastewater treatment plants. However, the information about microbial communities in aerobic granular systems dealing with industrial wastewater like pig slurry is limited. Herein, bacterial diversity and dynamics were assessed in a pilot scale plant using aerobic granular sludge for organic matter and nitrogen elimination from swine slurry during more than 300 days. Results indicated that bacterial composition evolved throughout the operational period from flocculent activated sludge, used as inoculum, to mature aerobic granules. Bacterial diversity increased at the beginning of the granulation process and then declined due to the application of transient organic matter and nitrogen loads. The operational conditions of the pilot plant and the degree of granulation determined the microbial community of the aerobic granules. Brachymonas, Zoogloea and Thauera were attributed with structural function as they are able to produce extracellular polymeric substances to maintain the granular structure. Nitrogen removal was justified by partial nitrification (Nitrosomonas) and denitrification (Thauera and Zoogloea), while Comamonas was identified as the main organic matter oxidizing bacteria. Overall, clear links between bacterial dynamics and composition with process performance were found and will help to predict their biological functions in wastewater ecosystems improving the future control of the process. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1212-1221, 2016. © 2016 American Institute of Chemical Engineers.

Thermal processing of paper sludge and characterisation of its pyrolysis products.

PubMed

Strezov, Vladimir; Evans, Tim J

2009-05-01

Paper sludge is a waste product from the paper and pulp manufacturing industry that is generally disposed of in landfills. Pyrolysis of paper sludge can potentially provide an option for managing this waste by thermal conversion to higher calorific value fuels, bio-gas, bio-oils and charcoal. This work investigates the properties of paper sludge during pyrolysis and energy required to perform thermal conversion. The products of paper sludge pyrolysis were also investigated to determine their properties and potential energy value. The dominant volatile species of paper sludge pyrolysis at 10 degrees C/min were found to be CO and CO(2), contributing to almost 25% of the paper sludge dry weight loss at 500 degrees C. The hydrocarbons (CH(4), C(2)H(4), C(2)H(6)) and hydrogen contributed to only 1% of the total weight loss. The bio-oils collected at 500 degrees C were primarily comprised of organic acids with the major contribution being linoleic acid, 2,4-decadienal acid and oleic acid. The high acidic content indicates that in order to convert the paper sludge bio-oil to bio-diesel or petrochemicals, further upgrading would be necessary. The charcoal produced at 500 degrees C had a calorific value of 13.3MJ/kg.

Destroying lignocellulosic matters for enhancing methane production from excess sludge.

PubMed

Hao, Xiaodi; Hu, Yuansheng; Cao, Daqi

2016-01-01

A lot of lignocellulosic matters are usually present in excess sludge, which are hardly degraded in anaerobic digestion (AD) and thus remains mostly in digested sludge. This is a reason why the conversion rate of sludge organics into energy (CH4) is often low. Obviously, the hydrolysis of AD cannot destruct the structure of lignocellulosic matters. Structural destruction of lignocellulosic matters has to be performed in AD. In this study, pretreatments with the same principles as cell disintegration of sludge were applied to destruct lignocellulosic matters so that these materials could be converted to CH4 via AD. Acid, alkali, thermal treatment and ultrasonic were used in the experiments to observe the destructed/degraded efficiency of lignocellulosic matters. Thermal treatment was found to be the most effective pretreatment. Under optimized conditions (T = 150 °C and t = 30  min), pretreated sludge had a degraded rate of 52.6% in AD, due to easy destruction and/or degradation of hemicelluloses and celluloses in pretreatment. The sludge pretreated by thermal treatment could enhance the CH4 yield (mL CH4 g(-1) VSS) by 53.6% compared to raw sludge. Economically, the thermal treatment can balance the input energy with the produced energy (steam and electricity).

Enhanced Cr bioleaching efficiency from tannery sludge with coinoculation of Acidithiobacillus thiooxidans TS6 and Brettanomyces B65 in an air-lift reactor.

PubMed

Fang, Di; Zhou, Li-Xiang

2007-09-01

Bioleaching process has been demonstrated to be an effective technology in removing Cr from tannery sludge, but a large quantity of dissolved organic matter (DOM) present in tannery sludge often exhibits a marked toxicity to chemolithoautotrophic bioleaching bacteria such as Acidithiobacillus thiooxidans. The purpose of the present study was therefore to enhance Cr bioleaching efficiencies through introducing sludge DOM-degrading heterotrophic microorganism into the sulfur-based sludge bioleaching system. An acid-tolerant DOM-degrading yeast strain Brettanomyces B65 was successfully isolated from a local Haining tannery sludge and it could metabolize sludge DOM as a source of energy and carbon for growth. A combined bioleaching experiment (coupling Brettanomyces B65 and A. thiooxidans TS6) performed in an air-lift reactor indicated that the rates of sludge pH reduction and ORP increase were greatly improved, resulting in enhanced Cr solubilization. Compared with the 5 days required for maximum solubilization of Cr for the control (single bioleaching process without inoculation of Brettanomyces B65), the bioleaching period was significantly shorten to 3 days for the combined bioleaching system. Moreover, little nitrogen and phosphorous were lost and the content of Cr was below the permitted levels for land application after 3 days of bioleaching treatment.

Pyrosequencing reveals the key microorganisms involved in sludge alkaline fermentation for efficient short-chain fatty acids production.

PubMed

Zheng, Xiong; Su, Yinglong; Li, Xiang; Xiao, Naidong; Wang, Dongbo; Chen, Yinguang

2013-05-07

Short-chain fatty acids (SCFAs) have been regarded as the excellent carbon source of wastewater biological nutrient removal, and sludge alkaline (pH 10) fermentation has been reported to achieve highly efficient SCFAs production. In this study, the underlying mechanisms for the improved SCFAs production at pH 10 were investigated by using 454 pyrosequencing and fluorescent in situ hybridization (FISH) to analyze the microbial community structures in sludge fermentation reactors. It was found that sludge fermentation at pH 10 increased the abundances of Pseudomonas sp. and Alcaligenes sp., which were able to excrete extracellular proteases and depolymerases, and thus enhanced the hydrolysis of insoluble sludge protein and polyhydroxyalkanoates (PHA). Meanwhile, the abundance of acid-producing bacteria (such as Clostridium sp.) in the reactor of pH 10 was also higher than that of uncontrolled pH, which benefited the acidification of soluble organic substrates. Further study indicated that sludge fermentation at pH 10 significantly decreased the number of methanogenic archaea, resulting in lower SCFAs consumption and lower methane production. Therefore, anaerobic sludge fermentation under alkaline conditions increased the abundances of bacteria involved in sludge hydrolysis and acidification, and decreased the abundance of methanogenic archaea, which favored the competition of bacteria over methanogens and resulted in the efficient production of SCFAs.

Black water sludge reuse in agriculture: are heavy metals a problem?

PubMed

Tervahauta, Taina; Rani, Sonia; Hernández Leal, Lucía; Buisman, Cees J N; Zeeman, Grietje

2014-06-15

Heavy metal content of sewage sludge is currently the most significant factor limiting its reuse in agriculture within the European Union. In the Netherlands most of the produced sewage sludge is incinerated, mineralizing the organic carbon into the atmosphere rather than returning it back to the soil. Source-separation of black water (toilet water) excludes external heavy metal inputs, such as industrial effluents and surface run-offs, producing sludge with reduced heavy metal content that is a more favorable source for resource recovery. The results presented in this paper show that feces is the main contributor to the heavy metal loading of vacuum collected black water (52-84%), while in sewage the contribution of feces is less than 10%. To distinguish black water from sewage in the sludge reuse regulation, a control parameter should be implemented, such as the Hg and Pb content that is significantly higher in sewage sludge compared to black water sludge (from 50- to 200-fold). The heavy metals in feces and urine are primarily from dietary sources, and promotion of the soil application of black water sludge over livestock manure and artificial fertilizers could further reduce the heavy metal content in the soil/food cycle. Copyright © 2014 Elsevier B.V. All rights reserved.

Pollutant removal characteristics of a two-influent-line BNR process performing denitrifying phosphorus removal: role of sludge recycling ratios.

PubMed

Liu, Hongbo; Leng, Feng; Chen, Piao; Kueppers, Stephan

2016-11-01

This paper studied denitrifying phosphorus removal of a novel two-line biological nutrient removal process treating low strength domestic wastewater under different sludge recycling ratios. Mass balance of intracellular compounds including polyhydroxyvalerate, polyhydroxybutyrate and glycogen was investigated together with total nitrogen (TN) and total phosphorus (TP). Results showed that sludge recycling ratios had a significant influence on the use of organics along bioreactors and 73.6% of the average removal efficiency was obtained when the influent chemical oxygen demand (COD) ranged from 175.9 mgL -1 to 189.9 mgL -1 . The process performed better under a sludge recycling ratio of 100% compared to 25% and 50% in terms of ammonia and COD removal rates. Overall, TN removal efficiency for 50% and 100% sludge recycling ratios were 56.4% and 61.9%, respectively, unlike the big gap for carbon utilization and the TP removal rates, indicating that the effect of sludge recycling ratio on the anaerobic compartments had been counteracted by change in the efficiency of other compartments. The higher ratio of sludge recycling was conducive to the removal of TN, not in favor of TP, and less influence on COD. Thus, 25% was considered to be the optimal sludge recycling ratio.

Review on innovative techniques in oil sludge bioremediation

NASA Astrophysics Data System (ADS)

Mahdi, Abdullah M. El; Aziz, Hamidi Abdul; Eqab, Eqab Sanoosi

2017-10-01

Petroleum hydrocarbon waste is produced in worldwide refineries in significant amount. In Libya, approximately 10,000 tons of oil sludge is generated in oil refineries (hydrocarbon waste mixtures) annually. Insufficient treatment of those wastes can threaten the human health and safety as well as our environment. One of the major challenges faced by petroleum refineries is the safe disposal of oil sludge generated during the cleaning and refining process stages of crude storage facilities. This paper reviews the hydrocarbon sludge characteristics and conventional methods for remediation of oil hydrocarbon from sludge. This study intensively focuses on earlier literature to describe the recently selected innovation technology in oily hydrocarbon sludge bioremediation process. Conventional characterization parameters or measurable factors can be gathered in chemical, physical, and biological parameters: (1) Chemical parameters are consequently necessary in the case of utilization of topsoil environment when they become relevant to the presence of nutrients and toxic compounds; (2) Physical parameters provide general data on sludge process and hand ability; (3) Biological parameters provide data on microbial activity and organic matter presence, which will be used to evaluate the safety of the facilities. The objective of this research is to promote the bioremediating oil sludge feasibility from Marsa El Hariga Terminal and Refinery (Tobruk).

Study on substrate metabolism process of saline waste sludge and its biological hydrogen production potential.

PubMed

Zhang, Zengshuai; Guo, Liang; Li, Qianqian; Zhao, Yangguo; Gao, Mengchun; She, Zonglian

2017-07-01

With the increasing of high saline waste sludge production, the treatment and utilization of saline waste sludge attracted more and more attention. In this study, the biological hydrogen production from saline waste sludge after heating pretreatment was studied. The substrate metabolism process at different salinity condition was analyzed by the changes of soluble chemical oxygen demand (SCOD), carbohydrate and protein in extracellular polymeric substances (EPS), and dissolved organic matters (DOM). The excitation-emission matrix (EEM) with fluorescence regional integration (FRI) was also used to investigate the effect of salinity on EPS and DOM composition during hydrogen fermentation. The highest hydrogen yield of 23.6 mL H 2 /g VSS and hydrogen content of 77.6% were obtained at 0.0% salinity condition. The salinity could influence the hydrogen production and substrate metabolism of waste sludge.

Thermal Behavior of Cd During Sludge Incineration: Experiments and Thermodynamic Equilibrium Model.

PubMed

Liu, Jingyong; Zhuo, Zhongxu; Sun, Shuiyu; Xie, Wuming; Lu, Shaoyou; Sun, Jian; Kuo, Jiahong; Yujie, Wang

2016-12-01

  Experiments and thermodynamic equilibrium calculations were performed to investigate the behavior of Cd during sewage sludge incineration. The chemical equilibrium calculations indicated that chlorine significantly increased the volatilization of Cd in the form of CdCl2. In addition, SiO2-containing materials can function as sorbents for stabilizing Cd. The effect of PVC added to the sludge on the migration of Cd in the sludge was greater than that of NaCl. As the temperature increased, both organic and inorganic chlorides reduced the Cd distribution in the bottom ash. The chloride concentration, and the incineration time exhibited insignificant changes in Cd emission. With the addition of either NaCl or PVC into the sludge, the phases of Cd present in the bottom slag were primarily present in the form of silica-alumina oxides or multi-metal oxide, which could inhabit the Cd volatilization.

[Study the restoration technology of concentrated application-natural diffusion about amendments of acidified soil of hilly woodland].

PubMed

Fang, Xiong; Liu, Ju-Xiu; Yin, Guang-Cai; Zhao, Liang; Liu, Shi-Zhong; Chu, Guo-Wei; Li, Yi-Yong

2013-01-01

Through concentrated application of lime, sewage sludge and lime + sewage sludge on the sloping top of the hilly woodlands, the restoration effects of the three soil amendments on the acidified soil of hilly woodland were studied. The results showed that: (1) Joint application of sewage sludge + lime can significantly (P < 0.05) decrease soil acidity, promote the rapid increase in soil organic matter and nitrogen content, increase soil cation exchange capacity, and effectively improve acidified soil. (2) Through natural diffusion mechanisms of surface and subsurface runoff, a large area of acidified soil of hilly woodlands can be restored by concentrated application of soil amendments on the sloping top of the hilly woodlands. (3) It is conducive to solve the pollution problems of the urban sewage sludge by using municipal sewage sludge to restore acidified soil, but only for the restoration of acidified soil of timber forest.

Feasibility Study on Manufacturing Lightweight Aggregates from Water Purification Sludge

NASA Astrophysics Data System (ADS)

Peng, Ching-Fang; Chen, How-Ji

2018-02-01

This study mainly discussed the feasibility of manufacturing lightweight aggregates from water purification sludge in Taiwan. They were analysed for the physical and chemical composition before the sintering test for lightweight aggregates in a laboratory. Then the physical and mechanical properties of the synthesized aggregates were assessed. The result showed that the chemical composition of sludge in the water purification plants was within the appropriate range for manufacturing lightweight aggregate as proposed in the literature. The sintering test demonstrated that the particle density of aggregates from the ten types of water purification sludge were mostly less than 1.8 g/cm3. In addition, the dry unit weight, the organic impurity, the ignition loss, and other characteristics of synthesized aggregates met the requirement of CNS standards, while its water absorption and crushing strength also fulfilled the general commercial specifications. Therefore, reclamation of water purification sludge for production of lightweight aggregate is indeed feasible.

Response surface methodology for the optimization of sludge solubilization by ultrasonic pre-treatment

NASA Astrophysics Data System (ADS)

Zheng, Mingyue; Zhang, Xiaohui; Lu, Peng; Cao, Qiguang; Yuan, Yuan; Yue, Mingxing; Fu, Yiwei; Wu, Libin

2018-02-01

The present study examines the optimization of the ultrasonic pre-treatment conditions with response surface experimental design in terms of sludge disintegration efficiency (solubilisation of organic components). Ultrasonic pre-treatment for the maximum solubilization with residual sludge enhanced the SCOD release. Optimization of the ultrasonic pre-treatment was conducted through a Box-Behnken design (three variables, a total of 17 experiments) to determine the effects of three independent variables (power, residence time and TS) on COD solubilization of sludge. The optimal COD was obtained at 17349.4mg/L, when the power was 534.67W, the time was 10.77, and TS was 2%, while the SE of this condition was 28792J/kg TS.

Clay-sewage sludge co-pyrolysis. A TG-MS and Py-GC study on potential advantages afforded by the presence of clay in the pyrolysis of wastewater sewage sludge

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

Ischia, Marco, E-mail: marco.ischia@ing.unitn.it; Maschio, Roberto Dal; Grigiante, Maurizio

2011-01-15

Wastewater sewage sludge was co-pyrolyzed with a well characterized clay sample, in order to evaluate possible advantages in the thermal disposal process of solid waste. Characterization of the co-pyrolysis process was carried out both by thermogravimetric-mass spectrometric (TG-MS) analysis, and by reactor tests, using a lab-scale batch reactor equipped with a gas chromatograph for analysis of the evolved gas phase (Py-GC). Due to the presence of clay, two main effects were observed in the instrumental characterization of the process. Firstly, the clay surface catalyzed the pyrolysis reaction of the sludge, and secondly, the release of water from the clay, atmore » temperatures of approx. 450-500 deg. C, enhanced gasification of part of carbon residue of the organic component of sludge following pyrolysis. Moreover, the solid residue remaining after pyrolysis process, composed of the inorganic component of sludge blended with clay, is characterized by good features for possible disposal by vitrification, yielding a vitreous matrix that immobilizes the hazardous heavy metals present in the sludge.« less

Complete solids retention activated sludge process.

PubMed

Amanatidou, E; Samiotis, G; Trikoilidou, E; Pekridis, G; Tsikritzis, L

2016-01-01

In a slaughterhouse's full-scale extended aeration activated sludge wastewater treatment plant (WWTP), operating under complete solids retention time, the evolution of mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) concentration, food to micro-organisms ratio (F/M) and substrate utilization rate (SUR) were studied for over a year. Biomass growth phases in correlation to sludge biological and morphological characteristics were studied. Three distinguished growth phases were observed during the 425 days of monitoring. The imposed operational conditions led the process to extended biomass starvation conditions, minimum F/M, minimum SUR and predator species growth. MLSS and MLVSS reached a stabilization phase (plateau phase) where almost zero sludge accumulation was observed. The concept of degradation of the considered non-biodegradable particulate compounds in influent and in biomass (cell debris) was also studied. Comparison of evolution of observed sludge yields (Yobs) in the WWTP with Yobs predictions by activated sludge models verified the degradation concept for the considered non-biodegradable compounds. Control of the sedimentation process was achieved, by predicting the solids loading rate critical point using state point analysis and stirred/unstirred settling velocity tests and by applying a high return activated sludge rate. The nitrogen gas related sedimentation problems were taken into consideration.

[Method for Simultaneous Determination of 11 Veterinary Antibiotics in Piggery Wastewater and Sludge and Its Application in Biological Treatment].

PubMed

Ding, Jia-li; Liu, Rui; Zheng, Wei; Yu, Wei-juan; Ye, Zhao-xia; Chen, Lu-jun; Zhang, Yong-ming

2015-10-01

In order to determine eleven commonly used veterinary antibiotics (including four tetracyclines, two sulfonamides, three quinolones and two macrolides) in piggery wastewater and activated sludge in the Yangtze River Delta region, the conditions of solid phase extraction and high performance liquid chromatography-tandem mass spectrometry were optimized. The recovery rate and relative standard deviations of the method were confirmed as 73% - 105.2%, 3.1% - 10.2% for piggery wastewater (n = 3) and 57.4% - 104.6%, 1.9% - 10.9% (n = 3) respectively for the activated sludge. Removal of antibiotics was then studied in a membrane bioreactor. The results showed that antibiotics of both tetracycline and sulfonamide species took a large portion in the wastewater, while tetracycline species were the dominant in the sludge. Tetracycline species in the wastewater were removed by 85.2%, mainly through biodegradation (51.9%) and secondly by sludge adsorption (33.2%). By comparison, sulfonamide species was removed by 95.8%, almost all through biodegradation while little by sludge adsorption. Flask tests suggested that the accumulated antibiotics in the sludge give no significant influence on the microbial removal of organics and ammonium.

Long-term simulation of the activated sludge process at the Hanover-Gümmerwald pilot WWTP.

PubMed

Makinia, Jacek; Rosenwinkel, Karl-Heinz; Spering, Volker

2005-04-01

The aim of this study was to obtain a validated model, consisting of the Activated Sludge Model No. 3 (ASM3) and the EAWAG bio-P module, which could be used as a decision tool for estimating the maximum allowable peak flow to wastewater treatment plants during stormwater conditions. The databases used for simulations originated from the Hanover-Gummerwald pilot plant subjected to a series of controlled, short-term hydraulic shock loading experiments. The continuous influent wastewater composition was generated using on-line measurements of only three parameters (COD, N-NH4+, P-PO4 3-). Model predictions were compared with on-line data from different locations in the activated sludge system including the aerobic zone (concentrations of N-NH4+, N-NO3-) and secondary effluent (concentrations of P-PO4 3-). The simulations confirmed experimental results concerning the capabilities of the system for handling increased flows during stormwater events. No (or minor) peaks of N-NH4+ were predicted for the line with the double dry weather flowrate, whereas peaks of N-NH4+ at the line with the quadruple dry weather flowrate were normally exceeding 8 g Nm(-3) (similar to the observations).

Plant-wide (BSM2) evaluation of reject water treatment with a SHARON-Anammox process.

PubMed

Volcke, E I P; Gernaey, K V; Vrecko, D; Jeppsson, U; van Loosdrecht, M C M; Vanrolleghem, P A

2006-01-01

In wastewater treatment plants (WWTPs) equipped with sludge digestion and dewatering systems, the reject water originating from these facilities contributes significantly to the nitrogen load of the activated sludge tanks, to which it is typically recycled. In this paper, the impact of reject water streams on the performance of a WWTP is assessed in a simulation study, using the Benchmark Simulation Model no. 2 (BSM2), that includes the processes describing sludge treatment and in this way allows for plant-wide evaluation. Comparison of performance of a WWTP without reject water with a WWTP where reject water is recycled to the primary clarifier, i.e. the BSM2 plant, shows that the ammonium load of the influent to the primary clarifier is 28% higher in the case of reject water recycling. This results in violation of the effluent total nitrogen limit. In order to relieve the main wastewater treatment plant, reject water treatment with a combined SHARON-Anammox process seems a promising option. The simulation results indicate that significant improvements of the effluent quality of the main wastewater treatment plant can be realized. An economic evaluation of the different scenarios is performed using an Operating Cost Index (OCI).

Mechanism and Parameter Optimization of Fenton’s Reagent Integrated with Surfactant Pretreatment to Improve Sludge Dewaterability

PubMed Central

Hong, Chen; Yang, Qiang; Feng, Lihui; Jia, Mengmeng; Li, Yifei

2017-01-01

Sludge dewatering can effectively reduce the volume and mass of sludge for subsequent treatment and disposal. The work validated the potential of Fenton’s reagent combined with dodecyl dimethyl benzyl ammonium chloride (DDBAC) in improving sludge dewaterability and proposed the mechanism of joint conditioning. The composite conditioner dosage was optimized using response surface methodology. Results indicated the good conditioning capability of the composite conditioners. The optimum dosages for H2O2, Fe2+, and DDBAC were 44.6, 39.6, and 71.0 mg/g, respectively, at which a sludge cake water content of 59.67% could be achieved. Moreover, a second-order polynomial equation was developed to describe the behavior of joint conditioning. Analysis of the reaction mechanism showed that Fenton oxidation effectively decomposed extracellular polymeric substance (EPS), including loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS), into dissolved organics, such as proteins and polysaccharides. The process facilitated the conversion of the bound water into free water. Furthermore, DDBAC further released the bound water through solubilization of TB-EPS and LB-EPS after the Fenton reaction. The bound water content of the sludge conditioned with Fenton’s reagent decreased from 3.15 to 1.36 g/g and further decreased to 1.08 g/g with the addition of DDBAC. High-performance liquid chromatography analysis verified that the composite conditioning could oxidize and hydrolyze EPS into low-molecular-mass organics (e.g., formic and acetic acid), thereby facilitating the release of bound water. PMID:28081203

Removal of personal care compounds from sewage sludge in reed bed container (lysimeter) studies--effects of macrophytes.

PubMed

Chen, Xijuan; Pauly, Udo; Rehfus, Stefan; Bester, Kai

2009-10-15

Sludge reed beds have been used for dewatering (draining and evapotranspiration) and mineralisation of sludge in Europe since 1988. Although reed beds are considered as a low cost and low contamination method in reducing volume, breaking down organic matter and increasing the density of sludge, it is not yet clear whether this enhanced biological treatment is suitable for degradation of organic micro-pollutants such as personal care products. Within this project the effect of biological sludge treatment in a reed bed on reducing the concentrations of the fragrances HHCB, AHTN, OTNE was studied as on the bactericide Triclosan. Additionally, the capacity of different macrophytes species to affect the treatment process was examined. Three different macrophyte species were compared: bulrush (Typha latifolia), reed (Phragmites australis) and reed canary grass (Phalaris arundinacea). They were planted into containers (lysimeters) with a size of 1 m x 1 m x 1 m which were filled with 20 cm gravel at the bottom and 50 cm sludge on top, into which the macrophytes were planted. During the twelve months experiment reduction of 20-30% for HHCB and AHTN, 70% for Triclosan and 70% for OTNE were determined under environmental conditions. The reduction is most likely due to degradation, since volatilization, uptake into plants and leaching are insignificant. No difference between the containers with different macrophyte species or the unplanted containers was observed. Considering the usual operation time of 10 years for reed beds, an assessment was made for the whole life time.

Ultrasonic disintegration of biosolids for improved biodegradation.

PubMed

Nickel, Klaus; Neis, Uwe

2007-04-01

Biological cell lysis is known to be the rate-limiting step of anaerobic biosolids degradation. Shear forces generated by low frequency ultrasound can be used to disintegrate bacterial cells in sewage sludge. Thus, the quantity of dissolved organic substrate is increased. Consequently, the degradation rate and the biodegradability of organic biosolids mass are improved. Fundamental pilot-studies showed a significantly accelerated biosolids degradation with less digested sludge being produced and increased biogas production being attained. A full-scale ultrasound reactor system was developed for continuous operation under real life conditions on sewage treatment plants (STP).

Biodegradation of PAHs and PCBs in soils and sludges

USGS Publications Warehouse

Liu, L.; Tindall, J.A.; Friedel, M.J.

2007-01-01

Results from a multi-year, pilot-scale land treatment project for PAHs and PCBs biodegradation were evaluated. A mathematical model, capable of describing sorption, sequestration, and biodegradation in soil/water systems, is applied to interpret the efficacy of a sequential active-passive biotreatment process of organic chemicals on remediation sites. To account for the recalcitrance of PAHs and PCBs in soils and sludges during long-term biotreatment, this model comprises a kinetic equation for organic chemical intraparticle sequestration process. Model responses were verified by comparison to measurements of biodegradation of PAHs and PCBs in land treatment units; a favorable match was found between them. Model simulations were performed to predict on-going biodegradation behavior of PAHs and PCBs in land treatment units. Simulation results indicate that complete biostabilization will be achieved when the concentration of reversibly sorbed chemical (S RA) reduces to undetectable levels, with a certain amount of irreversibly sequestrated residual chemical (S IA) remaining within the soil particle solid phase. The residual fraction (S IA) tends to lose its original chemical and biological activity, and hence, is much less available, toxic, and mobile than the "free" compounds. Therefore, little or no PAHs and PCBs will leach from the treatment site and constitutes no threat to human health or the environment. Biotreatment of PAHs and PCBs can be terminated accordingly. Results from the pilot-scale testing data and model calculations also suggest that a significant fraction (10-30%) of high-molecular-weight PAHs and PCBs could be sequestrated and become unavailable for biodegradation. Bioavailability (large K d , i.e., slow desorption rate) is the key factor limiting the PAHs degradation. However, both bioavailability and bioactivity (K in Monod kinetics, i.e., number of microbes, nutrients, and electron acceptor, etc.) regulate PCBs biodegradation. The sequential active-passive biotreatment can be a cost-effective approach for remediation of highly hydrophobic organic contaminants. The mathematical model proposed here would be useful in the design and operation of such organic chemical biodegradation processes on remediation sites. ?? 2007 Springer Science+Business Media B.V.

Sludge Biochar Amendment and Alfalfa Revegetation Improve Soil Physicochemical Properties and Increase Diversity of Soil Microbes in Soils from a Rare Earth Element Mining Wasteland

PubMed Central

Inubushi, Kazuyuki; Liang, Jian; Zhu, Sipin; Wei, Zhenya; Guo, Xiaobin; Luo, Xianping

2018-01-01

Long-term unregulated mining of ion-adsorption clays (IAC) in China has resulted in severe ecological destruction and created large areas of wasteland in dire need of rehabilitation. Soil amendment and revegetation are two important means of rehabilitation of IAC mining wasteland. In this study, we used sludge biochar prepared by pyrolysis of municipal sewage sludge as a soil ameliorant, selected alfalfa as a revegetation plant, and conducted pot trials in a climate-controlled chamber. We investigated the effects of alfalfa revegetation, sludge biochar amendment, and their combined amendment on soil physicochemical properties in soil from an IAC mining wasteland as well as the impact of sludge biochar on plant growth. At the same time, we also assessed the impacts of these amendments on the soil microbial community by means of the Illumina Miseq sequences method. Results showed that alfalfa revegetation and sludge biochar both improved soil physicochemical properties and microbial community structure. When alfalfa revegetation and sludge biochar amendment were combined, we detected additive effects on the improvement of soil physicochemical properties as well as increases in the richness and diversity of bacterial and fungal communities. Redundancy analyses suggested that alfalfa revegetation and sludge biochar amendment significantly affected soil microbial community structure. Critical environmental factors consisted of soil available K, pH, organic matter, carbon–nitrogen ratio, bulk density, and total porosity. Sludge biochar amendment significantly promoted the growth of alfalfa and changed its root morphology. Combining alfalfa the revegetation with sludge biochar amendment may serve to not only achieve the revegetation of IAC mining wasteland, but also address the challenge of municipal sludge disposal by making the waste profitable. PMID:29751652

Preliminary results of lab-scale investigations of products of incomplete combustion during incineration of primary and mixed digested sludge.

PubMed

Braguglia, C M; Bagnuolo, G; Gianico, A; Mininni, G; Pastore, C; Mascolo, G

2016-03-01

Separation between primary and secondary sludge treatment could be a valuable solution for sludge management. According to this approach, secondary sludge can be conveniently used in agriculture while primary sludge could be easily dried and incinerated. It follows that some concern may arise from incinerating primary sludge with respect to the current practice to incinerate mixed digested sludge. Incineration of primary and mixed digested municipal sludge was investigated with a lab-scale equipment in terms of emissions of products of incomplete combustion (PICs) during incineration failure modes. PICs can be grouped in three sub-categories, namely aliphatic hydrocarbons (alkanes and alkenes), compounds with a single aromatic ring, and polycyclic aromatic hydrocarbons (PAHs). After-burning temperature was the most important parameter to be controlled in order to minimize emissions of alkanes and alkenes. As for mono-aromatic compounds, benzene and toluene are the most thermally resistant compounds, and in some cases, an after-burning temperature of 1100 °C was not enough to get the complete destruction of benzene leading to a residual emission of 18 mg/kgsludge. PAHs showed an opposite trend with respect to aliphatic and mono-aromatic hydrocarbons being the thermal failure mode the main responsible of PIC emissions. A proper oxygen concentration is more important than elevated temperature thus reflecting the high thermal stability of PAHs. Overall, obtained results, even though obtained under flameless conditions that are different from those of the industrial plants, demonstrated that separation of primary and secondary sludge does not pose any drawbacks or concern regarding primary sludge being disposed of by incineration even though it is more contaminated than mixed digested sludge in terms of organic pollutants.

Sludge Biochar Amendment and Alfalfa Revegetation Improve Soil Physicochemical Properties and Increase Diversity of Soil Microbes in Soils from a Rare Earth Element Mining Wasteland.

PubMed

Luo, Caigui; Deng, Yangwu; Inubushi, Kazuyuki; Liang, Jian; Zhu, Sipin; Wei, Zhenya; Guo, Xiaobin; Luo, Xianping

2018-05-11

Long-term unregulated mining of ion-adsorption clays (IAC) in China has resulted in severe ecological destruction and created large areas of wasteland in dire need of rehabilitation. Soil amendment and revegetation are two important means of rehabilitation of IAC mining wasteland. In this study, we used sludge biochar prepared by pyrolysis of municipal sewage sludge as a soil ameliorant, selected alfalfa as a revegetation plant, and conducted pot trials in a climate-controlled chamber. We investigated the effects of alfalfa revegetation, sludge biochar amendment, and their combined amendment on soil physicochemical properties in soil from an IAC mining wasteland as well as the impact of sludge biochar on plant growth. At the same time, we also assessed the impacts of these amendments on the soil microbial community by means of the Illumina Miseq sequences method. Results showed that alfalfa revegetation and sludge biochar both improved soil physicochemical properties and microbial community structure. When alfalfa revegetation and sludge biochar amendment were combined, we detected additive effects on the improvement of soil physicochemical properties as well as increases in the richness and diversity of bacterial and fungal communities. Redundancy analyses suggested that alfalfa revegetation and sludge biochar amendment significantly affected soil microbial community structure. Critical environmental factors consisted of soil available K, pH, organic matter, carbon⁻nitrogen ratio, bulk density, and total porosity. Sludge biochar amendment significantly promoted the growth of alfalfa and changed its root morphology. Combining alfalfa the revegetation with sludge biochar amendment may serve to not only achieve the revegetation of IAC mining wasteland, but also address the challenge of municipal sludge disposal by making the waste profitable.

Reed beds receiving industrial sludge containing nitroaromatic compounds. Effects of outgoing water and bed material extracts in the umu-c genotoxicity assay, DR-CALUX assay and on early life stage development in zebrafish (Danio rerio).

PubMed

Gustavsson, Lillemor; Hollert, Henner; Jonsson, Sofie; van Bavel, Bert; Engwall, Magnus

2007-05-01

Sweden has prohibited the deposition of organic waste since January, 2005. Since 1 million tons of sludge is produced every year in Sweden and the capacity for incineration does not fill the demands, other methods of sludge management have to be introduced to a larger degree. One common method in the USA and parts of Europe is the use of wetlands to treat wastewater and sewage sludge. The capacity of reed beds to affect the toxicity of a complex mixture of nitroaromatics in sludge, however, is not fully elucidated. In this study, an industrial sludge containing explosives and pharmaceutical residues was therefore treated in artificial reed beds and the change in toxicity was studied. Nitroaromatic compounds, which are the main ingredients of many pharmaceuticals and explosives, are well known to cause cytotoxicity and genotoxicity. Recently performed studies have also showed that embryos of zebrafish (Danio rerio) are sensitive to nitroaromatic compounds. Therefore, we tested the sludge passing through constructed wetlands in order to detect any changes in levels of embryotoxicity, genotoxicity and dioxin-like activity (AhR-agonists). We also compared unplanted and planted systems in order to examine the impact of the root system on the fate of the toxicants. An industrial sludge containing a complex mixture of nitroaromatics was added daily to small-scale constructed wetlands (vertical flow), both unplanted and planted with Phragmites australis. Sludge with an average dry weight of 1.25%, was added with an average hydraulic loading rate of 1.2 L/day. Outgoing water was collected daily and stored at -20 degrees C. The artificial wetland sediment was Soxhlet extracted, followed by clean-up with multi-layer silica, or extracted by ultrasonic treatment, yielding one organic extract and one water extract of the same sample. Genotoxicity of the extracts was measured according to the ISO protocol for the umu-C genotoxicity assay (ISO/TC 147/SC 5/ WG9 N8), using Salmonella typhimurium TA1535/pSK1002 as test organism. Embryotoxicity and teratogenicity were studied using the fish egg assay with zebrafish (Danio rerio) and the dioxin-like activity was measured using the DR-CALUX assay. Chemical analyses of nitroaromatic compounds were performed using Solid Phase Micro Extraction (SPME) and GC-MS. Organic extracts of the bed material showed toxic potential in all three toxicity tests after two years of sludge loading. There was a difference between the planted and the unplanted beds, where the toxicity of organic extracts overall was higher in the bed material from the planted beds. The higher toxicity of the planted beds could have been caused by the higher levels of total carbon in the planted beds, which binds organic toxicants, and by enrichment caused by lower volumes of outgoing water from the planted beds. Developmental disorders were observed in zebrafish exposed directly in contact to bed material from unplanted beds, but not in fish exposed to bed material from planted beds. Hatching rates were slightly lower in zebrafish exposed to outgoing water from unplanted beds than in embryos exposed to outgoing water from planted beds. Genotoxicity in the outgoing water was below detection limit for both planted and unplanted beds. Most of the added toxicants via the sludge were unaccounted for in the outgoing water, suggesting that the beds had toxicant removal potential, although the mechanisms behind this remain unknown. During the experimental period, the beds received a sludge volume (dry weight) of around three times their own volume. In spite of this, the toxicity in the bed material was lower than in the sludge. Thus, the beds were probably able to actually decrease the toxicity of the added, sludge-associated toxicants. When testing the acetone extracts of the bed material, the planted bed showed a higher toxicity than the unplanted beds in all three toxicity tests. The toxicity of water extracts from the unplanted beds, detected by the fish egg assay, were higher than the water extracts from the planted beds. No genotoxicity was detected in outgoing water from either planted or unplanted beds. All this together indicates that the planted reed beds retained semi-lipophilic acetone-soluble toxic compounds from the sludge better than the unplanted beds, which tended to leak out more of the water soluble toxic compounds in the outgoing water. The compounds identified by SPME/GC in the outgoing water were not in sufficient concentrations to have caused induction in the genotoxicity test. This study has pointed out the benefits of using constructed wetlands receiving an industrial sludge containing a complex mixture of nitroaromatics to reduce toxicity in the outgoing water. The water from planted, constructed wetlands could therefore be directed to a recipient without further cleaning. The bed material should be investigated over a longer period of time in order to evaluate potential accumulation and leakage prior to proper usage or storage. The plants should be investigated in order to examine uptake and possible release when the plant biomass is degraded.

Experimental research of sewage sludge with coal and biomass co-combustion, in pellet form.

PubMed

Kijo-Kleczkowska, Agnieszka; Środa, Katarzyna; Kosowska-Golachowska, Monika; Musiał, Tomasz; Wolski, Krzysztof

2016-07-01

Increased sewage sludge production and disposal, as well as the properties of sewage sludge, are currently affecting the environment, which has resulted in legislation changes in Poland. Based on the Economy Minister Regulation of 16 July 2015 (Regulation of the Economy Minister, 2015) regarding the criteria and procedures for releasing wastes for landfilling, the thermal disposal of sewage sludge is important due to its gross calorific value, which is greater than 6MJ/kg, and the problems that result from its use and application. Consequently, increasingly restrictive legislation that began on 1 January 2016 was introduced for sewage sludge storage in Poland. Sewage sludge thermal utilisation is an attractive option because it minimizes odours, significantly reduces the volume of starting material and thermally destroys the organic and toxic components of the off pads. Additionally, it is possible that the ash produced could be used in different ways. Currently, as many as 11 plants use sewage sludge as fuel in Poland; thus, this technology must be further developed in Poland while considering the benefits of co-combustion with other fuels. This paper presents the results of experimental studies of the mechanisms and kinetics of sewage sludge, coal and biomass combustion and their co-combustion in spherical-pellet form. Compared with biomass, a higher temperature is required to ignite sewage sludge by flame. The properties of biomass and sewage sludge result in the intensification of the combustion process (by fast ignition of volatile matter). In contrast to coal, a combustion of sewage sludge is determined not only burning the char, but also the combustion of volatiles. The addition of sewage sludge to hard coal and lignite shortens combustion times compared with coal, and the addition of sewage sludge to willow Salix viminalis produces an increase in combustion time compared with willow alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor

PubMed Central

Guerrero-Barajas, Claudia; Ordaz, Alberto; García-Solares, Selene Montserrat; Garibay-Orijel, Claudio; Bastida-González, Fernando; Zárate-Segura, Paola Berenice

2015-01-01

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria. PMID:26555802

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor.

PubMed

Guerrero-Barajas, Claudia; Ordaz, Alberto; García-Solares, Selene Montserrat; Garibay-Orijel, Claudio; Bastida-González, Fernando; Zárate-Segura, Paola Berenice

2015-10-15

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria.

Effects of different sewage sludge applications on heavy metal accumulation, growth and yield of spinach (Spinacia oleracea L.).

PubMed

Eid, Ebrahem M; El-Bebany, Ahmed F; Alrumman, Sulaiman A; Hesham, Abd El-Latif; Taher, Mostafa A; Fawy, Khaled F

2017-04-03

In this study, we present the response of spinach to different amendment rates of sewage sludge (0, 10, 20, 30, 40 and 50 g kg -1 ) in a greenhouse pot experiment, where plant growth, biomass and heavy metal uptake were measured. The results showed that sewage sludge application increased soil electric conductivity (EC), organic matter, chromium and zinc concentrations and decreased soil pH. All heavy metal concentrations of the sewage sludge were below the permissible limits for land application of sewage sludge recommended by the Council of the European Communities. Biomass and all growth parameters (except the shoot/root ratio) of spinach showed a positive response to sewage sludge applications up to 40 g kg -1 compared to the control soil. Increasing the sewage sludge amendment rate caused an increase in all heavy metal concentrations (except lead) in spinach root and shoot. However, all heavy metal concentrations (except chromium and iron) were in the normal range and did not reach the phytotoxic levels. The spinach was characterized by a bioaccumulation factor <1.0 for all heavy metals. The translocation factor (TF) varied among the heavy metals as well as among the sewage sludge amendment rates. Spinach translocation mechanisms clearly restricted heavy metal transport to the edible parts (shoot) because the TFs for all heavy metals (except zinc) were <1.0. In conclusion, sewage sludge used in the present study can be considered for use as a fertilizer in spinach production systems in Saudi Arabia, and the results can serve as a management method for sewage sludge.

Comparison of thermophilic bacteria and alkyl polyglucose pretreatment on two-stage anaerobic digestion with waste sludge: Biogas production potential and substrate metabolism process.

PubMed

Guo, Liang; Zhang, Zengshuai; Gao, Mengchun; She, Zonglian; Zhao, Yangguo; Guo, Yiding; Sun, Jian

2018-02-01

To gain a better understanding of the influence on two-stage anaerobic digestion of waste sludge with thermophilic bacteria (TB) and alkyl polyglucose (APG) pretreatment, changing of soluble chemical oxygen demand (SCOD), carbohydrate and protein in extracellular polymeric substances (EPS) and dissolved organic matters (DOM) were analyzed. The excitation-emission matrix (EEM) with fluorescence regional integration (FRI) was also used to investigate compositional and structural characteristics of DOM. The highest hydrogen and methane yield of TB pretreated sludge was 12.2 ml/g VS (volatile suspended solid) and 124.7 ml/g VS, and that of APG pretreated sludge was 28.3 ml/g VS and 19.9 ml/g VS. The VS removal of TB pretreated sludge (36.7%) was higher than APG pretreated sludge (27.1%) in the two-stage anaerobic digestion. The APG pretreatment could inhibit the activity of methanogens and the substrate (such as volatile fatty acids (VFAs), protein and soluble microbial materials) was accumulated compared with TB pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Evaluating the Significance of Odor Gas Released During the Directly Drying Process of Sludge: Based on the Multi-index Integrated Assessment Method].

PubMed

Ding, Wen-jie; Chen, Wen-he; Deng, Ming-jia; Luo, Hui; Li, Lin; Liu, Jun-xin

2016-02-15

Co-processing of sewage sludge using the cement kiln can realize sludge harmless treatment, quantity reduction, stabilization and reutilization. The moisture content should be reduced to below 30% to meet the requirement of combustion. Thermal drying is an effective way for sludge desiccation. Odors and volatile organic compounds are generated and released during the sludge drying process, which could lead to odor pollution. The main odor pollutants were selected by the multi-index integrated assessment method. The concentration, olfactory threshold, threshold limit value, smell security level and saturated vapor pressure were considered as indexes based on the related regulations in China and foreign countries. Taking the pollution potential as the evaluation target, and the risk index and odor emission intensity as evaluation indexes, the odor pollution potential rated evaluation model of the pollutants was built according to the Weber-Fechner law. The aim of the present study is to form the rating evaluation method of odor potential pollution capacity suitable for the directly drying process of sludge.

Overview of current biological and thermo-chemical treatment technologies for sustainable sludge management.

PubMed

Zhang, Linghong; Xu, Chunbao Charles; Champagne, Pascale; Mabee, Warren

2014-07-01

Sludge is a semi-solid residue produced from wastewater treatment processes. It contains biodegradable and recalcitrant organic compounds, as well as pathogens, heavy metals, and other inorganic constituents. Sludge can also be considered a source of nutrients and energy, which could be recovered using economically viable approaches. In the present paper, several commonly used sludge treatment processes including land application, composting, landfilling, anaerobic digestion, and combustion are reviewed, along with their potentials for energy and product recovery. In addition, some innovative thermo-chemical techniques in pyrolysis, gasification, liquefaction, and wet oxidation are briefly introduced. Finally, a brief summary of selected published works on the life cycle assessment of a variety of sludge treatment and end-use scenarios is presented in order to better understand the overall energy balance and environmental burdens associated with each sludge treatment pathway. In all scenarios investigated, the reuse of bioenergy and by-products has been shown to be of crucial importance in enhancing the overall energy efficiency and reducing the carbon footprint. © The Author(s) 2014.

Levels and distribution patterns of short chain chlorinated paraffins in sewage sludge of wastewater treatment plants in China.

PubMed

Zeng, Lixi; Wang, Thanh; Ruan, Ting; Liu, Qian; Wang, Yawei; Jiang, Guibin

2012-01-01

Short chain chlorinated paraffins (SCCPs) are listed as persistent organic pollutant candidates in the Stockholm Convention and are receiving more and more attentions worldwide. In general, concentrations of contaminants in sewage sludge can give an important indication on their pollution levels at a local/regional basis. In this study, SCCPs were investigated in sewage sludge samples collected from 52 wastewater treatment plants in China. Concentrations of total SCCPs (ΣSCCPs) in sludge were in the range of 0.80-52.7 μg/g dry weight (dw), with a mean value of 10.7 μg/g dw. Most of SCCPs in the sludge samples showed a similar congener distribution patterns, and C(11) and Cl(7,8) were identified as the dominant carbon and chlorine congener groups. Significant linear relationships were found among different SCCP congener groups (r(2) ≥ 0.9). High concentrations of SCCPs in sewage sludge imply that SCCPs are widely present in China. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of sewage sludge and slow pyrolyzed sewage sludge-derived biochar for adsorption of phenanthrene and pyrene.

PubMed

Zielińska, Anna; Oleszczuk, Patryk

2015-09-01

The present study investigated the sorption of phenanthrene (PHE) and pyrene (PYR) by sewage sludges and sewage sludge-derived biochars. The organic carbon normalized distribution coefficient (log K(OC) for C(w) = 0.01 S(w)) for the sewage sludges ranged from 5.62 L kg(-1) to 5.64 L kg(-1) for PHE and from 5.72 L kg(-1) to 5.75 L kg(-1) for PYR. The conversion of sewage sludges into biochar significantly increased their sorption capacity. The value of log K(OC) for the biochars ranged from 5.54 L kg(-1) to 6.23 L kg(-1) for PHE and from 5.95 L kg(-1) to 6.52 L kg(-1) for PYR depending on temperature of pyrolysis. The dominant process was monolayer adsorption in the micropores and/or multilayer surface adsorption (in the mesopores), which was indicated by the significant correlations between log K(OC) and surface properties of biochars. PYR was sorbed better on the tested materials than PHE. Copyright © 2015 Elsevier Ltd. All rights reserved.

Toluene in sewage and sludge in wastewater treatment plants.

PubMed

Mrowiec, Bozena

2014-01-01

Toluene is a compound that often occurs in municipal wastewater ranging from detectable levels up to 237 μg/L. Before the year 2000, the presence of the aromatic hydrocarbons was assigned only to external sources. The Enhanced Biological Nutrients Removal Processes (EBNRP) work according to many different schemes and technologies. For high-efficiency biological denitrification and dephosphatation processes, the presence of volatile fatty acids (VFAs) in sewage is required. VFAs are the main product of organic matter hydrolysis from sewage sludge. However, no attention has been given to other products of the process. It has been found that in parallel to VFA production, toluene formation occurred. The formation of toluene in municipal anaerobic sludge digestion processes was investigated. Experiments were performed on a laboratory scale using sludge from primary and secondary settling tanks of municipal treatment plants. The concentration of toluene in the digested sludge from primary settling tanks was found to be about 42,000 μg/L. The digested sludge supernatant liquor returned to the biological dephosphatation and denitrification processes for sewage enrichment can contain up to 16,500 μg/L of toluene.

Improving municipal wastewater nitrogen and phosphorous removal by feeding sludge fermentation products to sequencing batch reactor (SBR).

PubMed

Yuan, Yue; Liu, Jinjin; Ma, Bin; Liu, Ye; Wang, Bo; Peng, Yongzhen

2016-12-01

This study presents a novel strategy to improve the removal efficiency of nitrogen and phosphorus from municipal wastewater by feeding sequencing batch reactor (SBR) with sludge alkaline fermentation products as carbon sources. The performances of two SBRs treating municipal wastewater (one was fed with sludge fermentation products; F-SBR, and the other without sludge fermentation products; B-SBR) were compared. The removal efficiencies of total nitrogen (TN) and phosphorus (PO 4 3- -P) were found to be 82.9% and 96.0% in F-SBR, while the corresponding values in B-SBR were 55.9% (TN) and -6.1% (PO 4 3- -P). Illumina MiSeq sequencing indicated that ammonium-oxidizing bacteria (Nitrosomonadaceae and Nitrosomonas) and denitrifying polyphosphate accumulating organisms (Dechloromonas) were enriched in F-SBR, which resulted in NO 2 - -N accumulation and denitrifying phosphorus removal via nitrite (DPRN). Moreover, feeding of sludge fermentation products reduced 862.1mg VSS/d of sludge in the F-SBR system (volume: 10L). Copyright © 2016 Elsevier Ltd. All rights reserved.

Design of long-term sludge-loading rates for forests under uncertainty

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

Crohn, D.M.

1995-09-01

A simple time series describing nitrate-nitrogen concentrations percolating form a sludge-amended forest is presented for the case where applications are made at several-year intervals. The time series converges to a quasi-steady-state solution that can be solved for an application rate limited by percolating nitrate-nitrogen concentrations. Excess nitrogen is commonly converted to nitrate, a form that leaches readily to pollute ground water. A chance constraint incorporates uncertainty associated with precipitation and evapotranspiration, the most important factors in determining the excess of water available for leaching. Design loading rates for eight New York state forest regions are discussed. If applications occur atmore » 3-year intervals, rates range form 0.2 to 5.3 Mg/ha dry weight depending on the design confidence level, local excess water patterns, forest nitrogen uptake, sludge type, and atmospheric nitrogen deposition rates. Results are compared to predictions made with FORSENTO, a comprehensive model for simulating sludge applications to northern hardwood forests. FORSENTO simulations suggest that mature hardwoods need only 12 kg/ha to support annually perennial material growth and that atmospheric nitrogen deposition may eventually meet or exceed needs of trees so that landspreading may not be sustainable indefinitely in some areas.« less

Fate and impacts of pharmaceuticals and personal care products after repeated applications of organic waste products in long-term field experiments.

PubMed

Bourdat-Deschamps, Marjolaine; Ferhi, Sabrina; Bernet, Nathalie; Feder, Fréderic; Crouzet, Olivier; Patureau, Dominique; Montenach, Denis; Moussard, Géraud D; Mercier, Vincent; Benoit, Pierre; Houot, Sabine

2017-12-31

Recycling organic waste products in agriculture is a potential route for the dispersion of pharmaceutical residues in the environment. In this study, the concentrations of thirteen pharmaceuticals and the personal care product triclosan (PPCPs) were determined in different environmental matrices from long-term experimental fields amended with different organic waste products (OWPs), including sludge, composted sludge with green wastes, livestock effluents and composted urban wastes applied at usual agricultural rates. PPCP concentrations were different in OWPs, varying from a few micrograms to milligrams per kilogram dry matter or per litre for slurry. OWPs from sludge or livestock effluents primarily contained antibiotics, whereas composted urban wastes primarily contained anti-inflammatory compounds. PPCP contents in soils amended for several years were less than a few micrograms per kilogram. The most persistent compounds (fluoroquinolones, carbamazepine) were quantified or detected in soils amended with sludge or composted sludge. In soils amended with composted municipal solid waste, carbamazepine was quantified, and fluoroquinolones, ibuprofen and diclofenac were sometimes detected. The small increases in fluoroquinolones and carbamazepine in soils after individual OWP applications were consistent with the fluxes from the applied OWP. The measured concentrations of pharmaceuticals in soil after several successive OWP applications were lower than the predicted concentrations because of degradation, strong sorption to soil constituents and/or leaching. Dissipation half-lives (DT 50 ) were approximately 750-2500, 900 and <300days for fluoroquinolones, carbamazepine and ibuprofen, respectively, in temperate soils and <350 and <80days for fluoroquinolones and doxycycline, respectively, in tropical soils. Detection frequencies in soil leachates were very low (below 7%), and concentrations ranged from the limits of detection (0.002-0.03μg/L) and exceptionally to 0.27μg/L. The most frequently detected pharmaceuticals were carbamazepine and ibuprofen. Based on the risk quotient, the estimated ecotoxicological risks for different soil organisms were low. Copyright © 2017 Elsevier B.V. All rights reserved.

Correlation between Organic Matter Degradation and the Rheological Performance of Waste Sludge During Anaerobic Digestion

NASA Astrophysics Data System (ADS)

Morel, Evangelina S.; Hernández-Hernándes, José A.; Méndez-Contreras, Juan M.; Cantú-Lozano, Denis

2008-07-01

Anaerobic digestion has demonstrated to be a good possibility to reduce the organic matter contents in waste activated sludge resulting in the effluents treatment. An anaerobic digestion was carried out in a 3.5 L reactor at 35 °C for a period of 20 days. An electronic thermostat controlled the temperature. The reactor was agitated at a rate of 200 rpm. The study of the rheological behavior of the waste activated sludge was done with an Anton Paar™ rheometer model MCR301 with a peltier plate for temperature control. Four-blade vane geometry was used with samples of 37 mL for determining rheological properties. Sampling (two samples) was taken every four days of anaerobic digestion through a peristaltic pump. The samples behavior was characterized by the Herschel-Bulkley model, with R2>0.99 for most cases. In all samples were found an apparent viscosity (ηap) and yield stress (τo) decrement when organic matter content diminishes. This demonstrates a relationship between rheological properties and organic matter concentration (% volatile solids). Also the flow activation energy (Ea) was calculated using the Ahrrenius correlation and samples of waste activated sludge before anaerobic digestion. In this case, samples were run in the rheometer at 200 rpm and a temperature range of 25 to 75 °C with an increment rate of 2 °C per minute. The yield stress observed was in a range of 0.93-0.18 Pa, the apparent viscosity was in a range of 0.0358-0.0010 Pa.s, the reduction of organic matter was in a range of 62.57-58.43% volatile solids and the average flow activation energy was 1.71 Calṡg-mol-1.

[Kinetic simulation of enhanced biological phosphorus removal with fermentation broth as carbon source].

PubMed

Zhang, Chao; Chen, Yin-Guang

2013-07-01

As a high-quality carbon source, fermentation broth could promote the phosphorus removal efficiency in enhanced biological phosphorus removal (EBPR). The transformation of substrates in EBPR fed with fermentation broth was well simulated using the modified activated sludge model No. 2 (ASM2) based on the carbon source metabolism. When fermentation broth was used as the sole carbon source, it was found that heterotrophic bacteria acted as a promoter rather than a competitor to the phosphorus accumulating organisms (PAO). When fermentation broth was used as a supplementary carbon source of real municipal wastewater, the wastewater composition was optimized for PAO growth; and the PAO concentration, which was increased by 3.3 times compared to that in EBPR fed with solely real municipal wastewater, accounting for about 40% of the total biomass in the reactor.

Innovative reuse of drinking water sludge in geo-environmental applications.

PubMed

Caniani, D; Masi, S; Mancini, I M; Trulli, E

2013-06-01

In recent years, the replacement of natural raw materials with new alternative materials, which acquire an economic, energetic and environmental value, has gained increasing importance. The considerable consumption of water has favoured the increase in the number of drinking water treatment plants and, consequently, the production of drinking water sludge. This paper proposes a protocol of analyses capable of evaluating chemical characteristics of drinking water sludge from surface water treatment plants. Thereby we are able to assess their possible beneficial use for geo-environmental applications, such as the construction of barrier layers for landfill and for the formation of "bio-soils", when mixed with the stabilized organic fraction of municipal solid waste. This paper reports the results of a study aimed at evaluating the quality and environmental aspects of reconstructed soils ("bio-soil"), which are used in much greater quantities than the usual standard, for "massive" applications in environmental actions such as the final cover of landfills. The granulometric, chemical and physical analyses of the sludge and the leaching test on the stabilized organic fraction showed the suitability of the proposed materials for reuse. The study proved that the reuse of drinking water sludge for the construction of barrier layers and the formation of "bio-soils" reduces the consumption of natural materials, the demand for landfill volumes, and offers numerous technological advantages. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sequential pretreatment for cell disintegration of municipal sludge in a neutral Bio-electro-Fenton system.

PubMed

Yu, Qilin; Jin, Xiaochen; Zhang, Yaobin

2018-05-15

Sludge cell disruption was generally considered as the rate-limiting step for the anaerobic digestion of waste activated sludge (WAS). Advanced oxidation processes and bio-electro-chemical systems were recently reported to enhance the hydrolysis of WAS and sludge cell disruption, while the cell-breaking processes of these systems remain unclear yet. In this study, an innovative Bio-electro-Fenton system was developed to pretreat the WAS sequentially with cathode Fenton process and anode anaerobic digestion. Significant cell disruption and dissolution intracellular organics were founded after the treatment. X-ray photoelectron spectroscopy (XPS) analysis and fourier transform infrared spectroscopy (FT-IR) spectra indicated that Gram-negative bacteria were more sensitive to free radicals yielded in cathode to induce a chain reaction that destroyed the lipid-contained outer membrane, while Gram-positive bacteria with thick peptidoglycan layer were liable to be biologically decomposed in the anode. Compared with the oxidation of organic matters in the cathode Fenton, the secretion of enzyme increased in the anode which was beneficial to break down the complex matters (peptidoglycans) into simples that were available for anode oxidation by exoelectrogens. The results also showed a possible prospect for the application of this sequential pretreatment in bio-electro-Fenton systems to disrupt sludge cells and enhance the anaerobic digestion. Copyright © 2018 Elsevier Ltd. All rights reserved.

13C-NMR Assessment of the Pattern of Organic Matter Transformation during Domestic Wastewater Treatment by Autothermal Aerobic Digestion (ATAD)

PubMed Central

Piterina, Anna V.; Barlett, John; Pembroke, J. Tony

2009-01-01

The pattern of biodegradation and the chemical changes occurring in the macromolecular fraction of domestic sludge during autothermal thermophilic aerobic digestion (ATAD) was monitored and characterised via solid-state 13C-NMR CP-MAS. Major indexes such as aromaticity, hydrophobicity and alkyl/O-alkyl ratios calculated for the ATAD processed biosolids were compared by means of these values to corresponding indexes reported for sludges of different origin such as manures, soil organic matter and certain types of compost. Given that this is the first time that these techniques have been applied to ATAD sludge, the data indicates that long-chain aliphatics are easily utilized by the microbial populations as substrates for metabolic activities at all stages of aerobic digestion and serve as a key substrate for the temperature increase, which in turn results in sludge sterilization. The ATAD biosolids following treatment had a prevalence of O-alkyl domains, a low aromaticity index (10.4%) and an alkyl/O-alkyl ratio of 0.48 while the hydrophobicity index of the sludge decreased from 1.12 to 0.62 during the treatment. These results have important implications for the evolution of new ATAD modalities particularly in relation to dewatering and the future use of ATAD processed biosolids as a fertilizer, particularly with respect to hydrological impacts on the soil behaviour. PMID:19742161

C-NMR assessment of the pattern of organic matter transformation during domestic wastewater treatment by autothermal aerobic digestion (ATAD).

PubMed

Piterina, Anna V; Barlett, John; Pembroke, J Tony

2009-08-01

The pattern of biodegradation and the chemical changes occurring in the macromolecular fraction of domestic sludge during autothermal thermophilic aerobic digestion (ATAD) was monitored and characterised via solid-state (13)C-NMR CP-MAS. Major indexes such as aromaticity, hydrophobicity and alkyl/O-alkyl ratios calculated for the ATAD processed biosolids were compared by means of these values to corresponding indexes reported for sludges of different origin such as manures, soil organic matter and certain types of compost. Given that this is the first time that these techniques have been applied to ATAD sludge, the data indicates that long-chain aliphatics are easily utilized by the microbial populations as substrates for metabolic activities at all stages of aerobic digestion and serve as a key substrate for the temperature increase, which in turn results in sludge sterilization. The ATAD biosolids following treatment had a prevalence of O-alkyl domains, a low aromaticity index (10.4%) and an alkyl/O-alkyl ratio of 0.48 while the hydrophobicity index of the sludge decreased from 1.12 to 0.62 during the treatment. These results have important implications for the evolution of new ATAD modalities particularly in relation to dewatering and the future use of ATAD processed biosolids as a fertilizer, particularly with respect to hydrological impacts on the soil behaviour.

Combined alkaline and ultrasonic pretreatment of sludge before aerobic digestion.

PubMed

Jin, Yiying; Li, Huan; Mahar, Rasool Bux; Wang, Zhiyu; Nie, Yongfeng

2009-01-01

Alkaline and ultrasonic sludge disintegration can be used as the pretreatment of waste activated sludge (WAS) to promote the subsequent anaerobic or aerobic digestion. In this study, different combinations of these two methods were investigated. The evaluation was based on the quantity of soluble chemical oxygen demand (SCOD) in the pretreated sludge as well as the degradation of organic matter in the subsequent aerobic digestion. For WAS samples with combined pretreatment, the released COD levels were higher than those with ultrasonic or alkaline pretreatment alone. When combined with the ultrasonic treatment, NaOH treatment was more efficient than Ca(OH)2 for WAS solubilization. The COD levels released in various sequential options of combined NaOH and ultrasonic treatments were in the the following descending order: simultaneous treatment > NaOH treatment followed by ultrasonic treatment > ultrasonic treatment followed by NaOH treatment. For simultaneous treatment, low NaOH dosage (100 g/kg dry solid), short duration (30 min) of NaOH treatment, and low ultrasonic specific energy (7500 kJ/kg dry solid) were suitable for sludge disintegration. Using combined NaOH and ultrasonic pretreatment with optimal parameters, the degradation efficiency of organic matter was increased from 38.0% to 50.7%, which is much higher than that with ultrasonic (42.5%) or with NaOH pretreatment (43.5%) in the subsequent aerobic digestion at the same retention time.

Adsorption of organic stormwater pollutants onto activated carbon from sewage sludge.

PubMed

Björklund, Karin; Li, Loretta Y

2017-07-15

Adsorption filters have the potential to retain suspended pollutants physically, as well as attracting and chemically attaching dissolved compounds onto the adsorbent. This study investigated the adsorption of eight hydrophobic organic compounds (HOCs) frequently detected in stormwater - including four polycyclic aromatic hydrocarbons (PAHs), two phthalates and two alkylphenols - onto activated carbon produced from domestic sewage sludge. Adsorption was studied using batch tests. Kinetic studies indicated that bulk adsorption of HOCs occurred within 10 min. Sludge-based activated carbon (SBAC) was as efficient as tested commercial carbons for adsorbing HOCs; adsorption capacities ranged from 70 to 2800 μg/g (C initial  = 10-300 μg/L; 15 mg SBAC in 150 mL solution; 24 h contact time) for each HOC. In the batch tests, the adsorption capacity was generally negatively correlated to the compounds' hydrophobicity (log K ow ) and positively associated with decreasing molecule size, suggesting that molecular sieving limited adsorption. However, in repeated adsorption tests, where competition between HOCs was more likely to occur, adsorbed pollutant loads exhibited strong positive correlation with log K ow . Sewage sludge as a carbon source for activated carbon has great potential as a sustainable alternative for sludge waste management practices and production of a high-capacity adsorption material. Copyright © 2017 Elsevier Ltd. All rights reserved.