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Sample records for aerobic biodegradation process

  1. Biodegradation and detoxification of textile azo dyes by bacterial consortium under sequential microaerophilic/aerobic processes

    PubMed Central

    Lade, Harshad; Kadam, Avinash; Paul, Diby; Govindwar, Sanjay

    2015-01-01

    Release of textile azo dyes to the environment is an issue of health concern while the use of microorganisms has proved to be the best option for remediation. Thus, in the present study, a bacterial consortium consisting of Providencia rettgeri strain HSL1 and Pseudomonas sp. SUK1 has been investigated for degradation and detoxification of structurally different azo dyes. The consortium showed 98-99 % decolorization of all the selected azo dyes viz. Reactive Black 5 (RB 5), Reactive Orange 16 (RO 16), Disperse Red 78 (DR 78) and Direct Red 81 (DR 81) within 12 to 30 h at 100 mg L-1 concentration at 30 ± 0.2 °C under microaerophilic, sequential aerobic/microaerophilic and microaerophilic/aerobic processes. However, decolorization under microaerophilic conditions viz. RB 5 (0.26 mM), RO 16 (0.18 mM), DR 78 (0.20 mM) and DR 81 (0.23 mM) and sequential aerobic/microaerophilic processes viz. RB 5 (0.08 mM), RO 16 (0.06 mM), DR 78 (0.07 mM) and DR 81 (0.09 mM) resulted into the formation of aromatic amines. In distinction, sequential microaerophilic/ aerobic process doesn’t show the formation of amines. Additionally, 62-72 % reduction in total organic carbon content was observed in all the dyes decolorized broths under sequential microaerophilic/aerobic processes suggesting the efficacy of method in mineralization of dyes. Notable induction within the levels of azoreductase and NADH-DCIP reductase (97 and 229 % for RB 5, 55 and 160 % for RO 16, 63 and 196 % for DR 78, 108 and 258 % for DR 81) observed under sequential microaerophilic/aerobic processes suggested their critical involvements in the initial breakdown of azo bonds, whereas, a slight increase in the levels of laccase and veratryl alcohol oxidase confirmed subsequent oxidation of formed amines. Also, the acute toxicity assay with Daphnia magna revealed the nontoxic nature of the dye-degraded metabolites under sequential microaerophilic/aerobic processes. As biodegradation under sequential microaerophilic/aerobic

  2. Simulation of aerobic and anaerobic biodegradation processes at a crude oil spill site

    USGS Publications Warehouse

    Essaid, Hedeff I.; Bekins, Barbara A.; Godsy, E. Michael; Warren, Ean; Baedecker, Mary Jo; Cozzarelli, Isabelle M.

    1995-01-01

    A two-dimensional, multispecies reactive solute transport model with sequential aerobic and anaerobic degradation processes was developed and tested. The model was used to study the field-scale solute transport and degradation processes at the Bemidji, Minnesota, crude oil spill site. The simulations included the biodegradation of volatile and nonvolatile fractions of dissolved organic carbon by aerobic processes, manganese and iron reduction, and methanogenesis. Model parameter estimates were constrained by published Monod kinetic parameters, theoretical yield estimates, and field biomass measurements. Despite the considerable uncertainty in the model parameter estimates, results of simulations reproduced the general features of the observed groundwater plume and the measured bacterial concentrations. In the simulation, 46% of the total dissolved organic carbon (TDOC) introduced into the aquifer was degraded. Aerobic degradation accounted for 40% of the TDOC degraded. Anaerobic processes accounted for the remaining 60% of degradation of TDOC: 5% by Mn reduction, 19% by Fe reduction, and 36% by methanogenesis. Thus anaerobic processes account for more than half of the removal of DOC at this site.

  3. Aerobic biodegradation of sludge with high hydrocarbon content generated by a Mexican natural gas processing facility.

    PubMed

    Roldán-Carrillo, T; Castorena-Cortés, G; Zapata-Peñasco, I; Reyes-Avila, J; Olguín-Lora, P

    2012-03-01

    The biodegradation of oil sludge from Mexican sour gas and petrochemical facilities contaminated with a high content of hydrocarbons, 334.7 ± 7.0 g kg(-1) dry matter (dm), was evaluated. Studies in microcosm systems were carried out in order to determine the capacity of the native microbiota in the sludge to reduce hydrocarbon levels under aerobic conditions. Different carbon/nitrogen/phosphorous (C/N/P) nutrient ratios were tested. The systems were incubated at 30 °C and shaken at 100 rpm. Hydrocarbon removals from 32 to 51% were achieved in the assays after 30 days of incubation. The best assay had C/N/P ratio of 100/1.74/0.5. The results of the Microtox(®) and Ames tests indicated that the original sludge was highly toxic and mutagenic, whereas the best assay gave a final product that did not show toxicity or mutagenicity.

  4. Aerobic biodegradation of selected monoterpenes.

    PubMed

    Misra, G; Pavlostathis, S G; Perdue, E M; Araujo, R

    1996-07-01

    Batch experiments were conducted to assess the biotransformation potential of four hydrocarbon monoterpenes (d-limonene, alpha-pinene, gamma-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and alpha-terpineol) under aerobic conditions at 23 degrees C. Both forest-soil extract and enriched cultures were used as inocula for the biodegradation experiments conducted first without, then with prior microbial acclimation to the monoterpenes tested. All four hydrocarbons and two alcohols were readily degraded. The increase in biomass and headspace CO2 concentrations paralleled the depletion of monoterpenes, thus confirming that terpene disappearance was the result of biodegradation accompanied by microbial growth and mineralization. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. A significant fraction of d-limonene-derived carbon was accounted for as non-extractable, dissolved organic carbon, whereas terpineol exhibited a much higher degree of utilization. The rate and extent of monoterpene biodegradation were not significantly affected by the presence of dissolved natural organic matter.

  5. Concomitant aerobic biodegradation of benzene and thiophene

    SciTech Connect

    Dyreborg, S.; Arvin, E.; Broholm, K.

    1998-05-01

    The concomitant aerobic biodegradation of benzene and thiophene was investigated in microcosm experiments using a groundwater enrichment culture. Benzene was biodegraded within 1 d, whereas thiophene could not be biodegraded as the sole source of carbon and energy. Some interesting phenomena were observed when both benzene and thiophene were present. In most cases, removal of thiophene was observed, and the removal occurred concomitantly with the biodegradation of benzene, suggesting that benzene was used as a primary substrate in the cometabolic biodegradation of thiophene. No biodegradation of the two compounds was observed for some combinations of concentrations, suggesting that thiophene could act as an inhibitor to benzene biodegradation. However, this effect could be overcome if more benzene was added to the microcosm. Residual concentrations of benzene and thiophene were observed in some microcosms and the data indicated that the biodegradation of the two compounds stopped when a critical threshold ratio between the concentrations of thiophene and benzene was reached. This ratio varied between 10 and 20. Results from modeling the biodegradation data suggested that thiophene was cometabolized concomitantly with the biodegradation of benzene and that the biodegradation may be described by a modified model based on a traditional model with an inhibition term incorporated.

  6. Decolorization and biodegradation of Rubine GFL by microbial consortium GG-BL in sequential aerobic/microaerophilic process.

    PubMed

    Waghmode, Tatoba R; Kurade, Mayur B; Lade, Harshad S; Govindwar, Sanjay P

    2012-07-01

    This study represents the development of a new batch method by consortium GG-BL using two microbial cultures viz., Galactomyces geotrichum MTCC 1360 and Brevibacillus laterosporus MTCC 2298, by varying environmental conditions for the decolorization and biodegradation of Rubine GFL. Consortium was found to give better decolorization and degradation of Rubine GFL as compared to the individual microorganism at aerobic/microaerophilic process. The consortial metabolic activity of these strains lead to 100% decolorization of Rubine GFL (50 mg/L) within 30 h with significant reduction in chemical oxygen demand (79%) and total organic carbon (68%). Induction in the activities of laccase, veratryl alcohol oxidase, tyrosinase, azo reductase, and riboflavin reductase suggested their role in the decolorization process. Nondenaturing polyacrylamide gel electrophoresis analysis showed differential induction pattern of oxidoreductive enzymes during decolorization of the dye at different incubation temperatures. The degradation of Rubine GFL into different metabolites by individual organism and in consortium was confirmed using high performance thin layer chromatography, high performance liquid chromatography, Fourier transform infrared spectroscopy, and gas chromatography-mass spectroscopy analysis. Phytotoxicity studies revealed nontoxic nature of the metabolites of Rubine GFL.

  7. Characterization and aerobic biodegradation of selected monoterpenes

    SciTech Connect

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M.

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  8. Assessing Enhanced Anaerobic and Intrinsic Aerobic Biodegradation of Trichloroethene

    NASA Astrophysics Data System (ADS)

    Sorenson, K. S.; Ely, R. L.; Martin, J. P.; Alvarez-Cohen, L.; Kauffman, M. E.

    2001-12-01

    Biodegradation of chloroethenes can proceed either anaerobically or aerobically; however, the techniques for monitoring the two pathways are quite different. At the Idaho National Engineering and Environmental Laboratory's Test Area North (TAN, a combination of anaerobic and aerobic biodegradation of trichloroethene (TCE) is being employed for restoration of a large plume of contaminated groundwater. During stimulation of anaerobic biodegradation of TCE through lactate addition, several assessment tools have proven effective for various objectives. Monitoring TCE and its lesser chlorinated degradation products provides a straightforward assessment tool for the occurrence of degradation. It does not, however, provide information regarding the potential for reductive dechlorination, nor progress from less suitable to more suitable conditions. A technique for obtaining this information is monitoring redox-sensitive geochemical parameters such as dissolved iron, sulfate, methane, and oxidation-reduction potential. This approach was demonstrated by the strong correlation of steps in the reductive dechlorination pathway to redox conditions at the TAN site. Yet another tool is required to determine adequacy of conditions for efficient dechlorination. Dechlorination efficiency appears to be dependent upon the predominant electron donor utilization (or fermentation) process occurring at any given time, an observation consistent with thermodynamic considerations. Thus, monitoring of added electron donor and intermediate product concentrations can help determine an efficient operations strategy. One final tool demonstrated at the TAN site was monitoring stable carbon isotope ratios. As TCE was dechlorinated, a clear fractionation occurred from cis-dichloroethene to vinyl chloride, and from vinyl chloride to ethene. This fractionation provides a clear signature of reductive dechlorination. Assessment of aerobic biodegradation of chloroethenes at TAN is more challenging because

  9. Biodegradability of biodegradable/degradable plastic materials under aerobic and anaerobic conditions.

    PubMed

    Mohee, R; Unmar, G D; Mudhoo, A; Khadoo, P

    2008-01-01

    A study was conducted on two types of plastic materials, Mater-Bi Novamont (MB) and Environmental Product Inc. (EPI), to assess their biodegradability under aerobic and anaerobic conditions. For aerobic conditions, organic fractions of municipal solid wastes were composted. For the anaerobic process, anaerobic inoculum from a wastewater treatment plant was used. Cellulose filter papers (CFP) were used as a positive control for both mediums. The composting process was monitored in terms of temperature, moisture and volatile solids and the biodegradation of the samples were monitored in terms of mass loss. Monitoring results showed a biodegradation of 27.1% on a dry basis for MB plastic within a period of 72 days of composting. Biodegradability under an anaerobic environment was monitored in terms of biogas production. A cumulative methane gas production of 245 ml was obtained for MB, which showed good degradation as compared to CFP (246.8 ml). However, EPI plastic showed a cumulative methane value of 7.6 ml for a period of 32 days, which was close to the blank (4.0 ml). The EPI plastic did not biodegrade under either condition. The cumulative carbon dioxide evolution after 32 days was as follows: CFP 4.406 cm3, MB 2.198 cm3 and EPI 1.328 cm3. The cumulative level of CO2 varying with time fitted sigmoid type curves with R2 values of 0.996, 0.996 and 0.995 for CFP, MB and EPI, respectively.

  10. Integrated Anaerobic-Aerobic Biodegradation of Multiple Contaminants Including Chlorinated Ethylenes, Benzene, Toluene, and Dichloromethane.

    PubMed

    Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

    2017-01-01

    Complete bioremediation of soils containing multiple volatile organic compounds (VOCs) remains a challenge. To explore the possibility of complete bioremediation through integrated anaerobic-aerobic biodegradation, laboratory feasibility tests followed by alternate anaerobic-aerobic and aerobic-anaerobic biodegradation tests were performed. Chlorinated ethylenes, including tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), and vinyl chloride (VC), and dichloromethane (DCM) were used for anaerobic biodegradation, whereas benzene, toluene, and DCM were used for aerobic biodegradation tests. Microbial communities involved in the biodegradation tests were analyzed to characterize the major bacteria that may contribute to biodegradation. The results demonstrated that integrated anaerobic-aerobic biodegradation was capable of completely degrading the seven VOCs with initial concentration of each VOC less than 30 mg/L. Benzene and toluene were degraded within 8 days, and DCM was degraded within 20 to 27 days under aerobic conditions when initial oxygen concentrations in the headspaces of test bottles were set to 5.3% and 21.0%. Dehalococcoides sp., generally considered sensitive to oxygen, survived aerobic conditions for 28 days and was activated during the subsequent anaerobic biodegradation. However, degradation of cis-DCE was suppressed after oxygen exposure for more than 201 days, suggesting the loss of viability of Dehalococcoides sp., as they are the only known anaerobic bacteria that can completely biodegrade chlorinated ethylenes to ethylene. Anaerobic degradation of DCM following previous aerobic degradation was complete, and yet-unknown microbes may be involved in the process. The findings may provide a scientific and practical basis for the complete bioremediation of multiple contaminants in situ and a subject for further exploration.

  11. Could petroleum biodegradation be a joint achievement of aerobic and anaerobic microrganisms in deep sea reservoirs?

    PubMed Central

    2011-01-01

    Several studies suggest that petroleum biodegradation can be achieved by either aerobic or anaerobic microorganisms, depending on oxygen input or other electron acceptors and appropriate nutrients. Evidence from in vitro experiments with samples of petroleum formation water and oils from Pampo Field indicate that petroleum biodegradation is more likely to be a joint achievement of both aerobic and anaerobic bacterial consortium, refining our previous observations of aerobic degradation. The aerobic consortium depleted, in decreasing order, hydrocarbons > hopanes > steranes > tricyclic terpanes while the anaerobic consortium depleted hydrocarbons > steranes > hopanes > tricyclic terpanes. The oxygen content of the mixed consortia was measured from time to time revealing alternating periods of microaerobicity (O2 ~0.8 mg.L-1) and of aerobicity (O2~6.0 mg.L-1). In this experiment, the petroleum biodegradation changed from time to time, alternating periods of biodegradation similar to the aerobic process and periods of biodegradation similar to the anaerobic process. The consortia showed preferences for metabolizing hydrocarbons > hopanes > steranes > tricyclic terpanes during a 90-day period, after which this trend changed and steranes were more biodegraded than hopanes. The analysis of aerobic oil degrading microbiota by the 16S rRNA gene clone library detected the presence of Bacillus, Brevibacterium, Mesorhizobium and Achromobacter, and the analysis of the anaerobic oil degrading microbiota using the same technique detected the presence of Bacillus and Acinetobacter (facultative strains). In the mixed consortia Stenotrophomonas, Brevibacterium, Bacillus, Rhizobium, Achromobacter and 5% uncultured bacteria were detected. This is certainly a new contribution to the study of reservoir biodegradation processes, combining two of the more important accepted hypotheses. PMID:22196374

  12. Structure-biodegradability study and computer-automated prediction of aerobic biodegradation of chemicals

    SciTech Connect

    Klopman, G.; Tu, M.

    1997-09-01

    It is shown that a combination of two programs, MultiCASE and META, can help assess the biodegradability of industrial organic materials in the ecosystem. MultiCASE is an artificial intelligence computer program that had been trained to identify molecular substructures believed to cause or inhibit biodegradation and META is an expert system trained to predict the aerobic biodegradation products of organic molecules. These two programs can be used to help evaluate the fate of disposed chemicals by estimating their biodegradability and the nature of their biodegradation products under conditions that may model the environment.

  13. Physicochemical treatments of anionic surfactants wastewater: Effect on aerobic biodegradability.

    PubMed

    Aloui, Fathi; Kchaou, Sonia; Sayadi, Sami

    2009-05-15

    The effect of different physicochemical treatments on the aerobic biodegradability of an industrial wastewater resulting from a cosmetic industry has been investigated. This industrial wastewater contains 11423 and 3148mgL(-1) of chemical oxygen demand (COD) and anionic surfactants, respectively. The concentration of COD and anionic surfactants were followed throughout the diverse physicochemical treatments and biodegradation experiments. Different pretreatments of this industrial wastewater using chemical flocculation process with lime and aluminium sulphate (alum), and also advanced oxidation process (electro-coagulation (Fe and Al) and electro-Fenton) led to important COD and anionic surfactants removals. The best results were obtained using electro-Fenton process, exceeding 98 and 80% of anionic surfactants and COD removals, respectively. The biological treatment by an isolated strain Citrobacter braakii of the surfactant wastewater, as well as the pretreated wastewater by the various physicochemical processes used in this study showed that the best results were obtained with electro-Fenton pretreated wastewater. The characterization of the treated surfactant wastewater by the integrated process (electro-coagulation or electro-Fenton)-biological showed that it respects Tunisian discharge standards.

  14. Evaluation of Biodegradability of Waste Before and After Aerobic Treatment

    NASA Astrophysics Data System (ADS)

    Suchowska-Kisielewicz, Monika; Jędrczak, Andrzej; Sadecka, Zofia

    2014-12-01

    An important advantage of use of an aerobic biostabilization of waste prior to its disposal is that it intensifies the decomposition of the organic fraction of waste into the form which is easily assimilable for methanogenic microorganisms involved in anaerobic decomposition of waste in the landfill. In this article it is presented the influence of aerobic pre-treatment of waste as well as leachate recirculation on susceptibility to biodegradation of waste in anaerobic laboratory reactors. The research has shown that in the reactor with aerobically treated waste stabilized with recilculation conversion of the organic carbon into the methane is about 45% higher than in the reactor with untreated waste stabilized without recirculation.

  15. Kinetics and thermodynamics of biodegradation of hydrolyzed polyacrylamide under anaerobic and aerobic conditions.

    PubMed

    Zhao, Lanmei; Bao, Mutai; Yan, Miao; Lu, Jinren

    2016-09-01

    Kinetics and thermodynamics of hydrolyzed polyacrylamide (HPAM) biodegradation in anaerobic and aerobic activated sludge biochemical treatment systems were explored to determine the maximum rate and feasibility of HPAM biodegradation. The optimal nutrient proportions for HPAM biodegradation were determined to be 0.08g·L(-1) C6H12O6, 1.00g·L(-1) NH4Cl, 0.36g·L(-1) NaH2PO4 and 3.00g·L(-1) K2HPO4 using response surface methodology (RSM). Based on the kinetics, the maximum HPAM biodegradation rates were 16.43385mg·L(-1)·d(-1) and 2.463mg·L(-1)·d(-1) in aerobic and anaerobic conditions, respectively. The activation energy (Ea) of the aerobic biodegradation was 48.9897kJ·mol(-1). Entropy changes (ΔS) of biochemical treatment system decreased from 216.21J·K(-1) to 2.39J·K(-1). Thermodynamic windows of opportunity for HPAM biodegradation were drawn. And it demonstrated HPAM was biodegraded into acetic acid and CO2 under laboratory conditions. Growth-process equations for functional bacteria anaerobically grown on polyacrylic acid were constructed and it confirmed electron equivalence between substrate and product.

  16. Communal microaerophilic-aerobic biodegradation of Amaranth by novel NAR-2 bacterial consortium.

    PubMed

    Chan, Giek Far; Rashid, Noor Aini Abdul; Chua, Lee Suan; Ab llah, Norzarini; Nasiri, Rozita; Ikubar, Mohamed Roslan Mohamad

    2012-02-01

    A novel bacterial consortium, NAR-2 which consists of Citrobacter freundii A1, Enterococcus casseliflavus C1 and Enterobacter cloacae L17 was investigated for biodegradation of Amaranth azo dye under sequential microaerophilic-aerobic condition. The NAR-2 bacterial consortium with E. casseliflavus C1 as the dominant strain enhanced the decolorization process resulting in reduction of Amaranth in 30 min. Further aerobic biodegradation, which was dominated by C. freundii A1 and E. cloacae L17, allowed biotransformation of azo reduction intermediates and mineralization via metabolic pathways including benzoyl-CoA, protocatechuate, salicylate, gentisate, catechol and cinnamic acid. The presence of autoxidation products which could be metabolized to 2-oxopentenoate was elucidated. The biodegradation mechanism of Amaranth by NAR-2 bacterial consortium was predicted to follow the steps of azo reduction, deamination, desulfonation and aromatic ring cleavage. This is for the first time the comprehensive microaerophilic-aerobic biotransformation pathways of Amaranth dye intermediates by bacterial consortium are being proposed.

  17. Compartment model of aerobic and anaerobic biodegradation in a municipal solid waste landfill.

    PubMed

    Kim, Sang-Yul; Tojo, Yasumasa; Matsuto, Toshihiko

    2007-12-01

    The mathematical formulations in a one-dimensional compartment model of the biodegradation of organic landfill components are described. The model is designed to switch between anaerobic and aerobic conditions, depending on the local oxygen concentration. The model also includes the effect of environmental factors, such as moisture content, pH, and temperature, on reaction rates. The model includes not only biodegradation processes for carbon compounds (acetate, CO2, CH4), but also for nitrogen compounds involved in nitrification and denitrification due to their significance in landfills. Two example runs to simulate anaerobic and aerobic waste were conducted for a single landfill unit cell by changing the organic content and diffusion coefficient.

  18. Comparative studies of aerobic and anaerobic biodegradation of methylparaben and propylparaben in activated sludge.

    PubMed

    Wu, Yang; Sun, Qian; Wang, Yu-Wen; Deng, Cheng-Xun; Yu, Chang-Ping

    2017-04-01

    The biodegradability of two typical parabens (methylparaben and propylparaben) in activated sludge, at initial concentrations of 1mgL(-1) or 10mgL(-1), was investigated under aerobic and anaerobic conditions. The results showed that microorganisms played a key role in degradation of parabens in WWTPs, especially in aerobic systems. The half-lives of methylparaben and propylparaben under aerobic conditions have been estimated to range between 15.8 and 19.8min, and benzoic acid was found to be one of the major biodegradation products. The calculated biodegradation efficiency of methylparaben and propylparaben in activated sludge under aerobic conditions was significantly higher than that observed under anaerobic (nitrate, sulfate, and Fe (III) reducing) conditions, as methylparaben and propylparaben exhibited comparatively higher persistence in anaerobic systems, with half-lives ≥43.3h and ≥8.6h, respectively. Overall, the results of this study imply that the majority of these parabens can be eliminated by aerobic biodegradation during conventional wastewater treatment processes, whereas minor removal is possible in anaerobic systems if an insufficient hydraulic retention time was maintained.

  19. Impact of batch, repeated-batch (with cell recycle and medium replacement) and continuous processes on the course and efficiency of aerobic thermophilic biodegradation of potato processing wastewater.

    PubMed

    Lasik, Małgorzata; Nowak, Jacek; Krzywonos, Małgorzata; Cibis, Edmund

    2010-05-01

    The aim of the study was to assess the course and efficiency of aerobic thermophilic treatment of a high-strength (COD=35gO(2)/l) effluent from potato processing. A comparative analysis was conducted of the treatment effects achieved using batch, repeated-batch (with cell recycle and medium replacement) and continuous treatment operations. The analysis consisted in (1) examining the extent of removal for the major parameters of the wastewater: COD, TOC, TN and TP (chemical oxygen demand, total organic carbon, total nitrogen and total phosphorus), and (2) determining the impact of oxygen deficit on the formation and assimilation of organic acids in the course of the three treatment operations. When use was made of the repeated-batch operation, the values of the COD and TOC removal rates were more than twice as high as those obtained with the continuous process, and more than five times as high as those obtained with the batch process.

  20. Biodegradation of Asphalt Cement-20 by Aerobic Bacteria

    PubMed Central

    Pendrys, John P.

    1989-01-01

    Seven gram-negative, aerobic bacteria were isolated from a mixed culture enriched for asphalt-degrading bacteria. The predominant genera of these isolates were Pseudomonas, Acinetobacter, Alcaligenes, Flavimonas, and Flavobacterium. The mixed culture preferentially degraded the saturate and naphthene aromatic fractions of asphalt cement-20. A residue remained on the surface which was resistant to biodegradation and protected the underlying asphalt from biodegradation. The most potent asphalt-degrading bacterium, Acinetobacter calcoaceticus NAV2, excretes an emulsifier which is capable of emulsifying the saturate and naphthene aromatic fractions of asphalt cement-20. This emulsifier is not denatured by phenol. PMID:16347928

  1. Aerobic biodegradation of trichloroethylene by microorganisms that degrade aromatic compounds

    SciTech Connect

    Lu, C.J.; Chang, C.Y.; Lee, C.M.

    1995-12-31

    Aerobic biodegradation of trichloroethylene (TCE) at an initial concentration of 80 mg/L with and without the presence of an aromatic compound was conducted with a series of batch reactors. The target aromatic compounds were benzene, toluene, and catechol. The aromatics-acclimated microorganisms were used as the cell source for the batch study. The results indicated that the presence of an aromatic compound was required to initiate the aerobic biodegradation of TCE by the aromatic-utilizing microorganisms. The addition of benzene or toluene initiated the removal of TCE. However, TCE removal was not proportional to the initial concentration of the aromatic compounds. The presence of an aromatic compound at an initial concentration of 5 mg/L resulted in better TCE removal in comparison with that at 1 or 20 mg/L. TCE removal was still significant after the depletion of the aromatic compound, but at a lower rate. The presence of catechol, an intermediate of the biodegradation of an aromatic compound, did not initiate the biodegradation of TCE by the catechol-utilizing microorganisms.

  2. Biodegradation of aniline by Candida tropicalis AN1 isolated from aerobic granular sludge.

    PubMed

    Wang, Dianzhan; Zheng, Guanyu; Wang, Shimei; Zhang, Dewei; Zhou, Lixiang

    2011-01-01

    Aniline-degrading microbes were cultivated and acclimated with the initial activated sludge collected from a chemical wastewater treatment plant. During the acclimation processes, aerobic granular sludge being able to effectively degrade aniline was successfully formed, from which a preponderant bacterial strain was isolated and named as AN1. Effects of factors including pH, temperature, and second carbon/nitrogen source on the biodegradation of aniline were investigated. Results showed that the optimal conditions for the biodegradation of aniline by the strain AN1 were at pH 7.0 and 28-35 degrees C. At the optimal pH and temperature, the biodegradation rate of aniline could reach as high as 17.8 mg/(L x hr) when the initial aniline concentration was 400 mg/L. Further studies revealed that the addition of 1 g/L glucose or ammonium chloride as a second carbon or nitrogen source could slightly enhance the biodegradation efficiency from 93.0% to 95.1%-98.5%. However, even more addition of glucose or ammonium could not further enhance the biodegradation process but delayed the biodegradation of aniline by the strain AN1. Based on morphological and physiological characteristics as well as the phylogenetic analysis of 26S rDNA sequences, the strain AN1 was identified as Candida tropicalis.

  3. Modeling of vapor intrusion from hydrocarbon-contaminated sources accounting for aerobic and anaerobic biodegradation

    NASA Astrophysics Data System (ADS)

    Verginelli, Iason; Baciocchi, Renato

    2011-11-01

    A one-dimensional steady state vapor intrusion model including both anaerobic and oxygen-limited aerobic biodegradation was developed. The aerobic and anaerobic layer thickness are calculated by stoichiometrically coupling the reactive transport of vapors with oxygen transport and consumption. The model accounts for the different oxygen demand in the subsurface required to sustain the aerobic biodegradation of the compound(s) of concern and for the baseline soil oxygen respiration. In the case of anaerobic reaction under methanogenic conditions, the model accounts for the generation of methane which leads to a further oxygen demand, due to methane oxidation, in the aerobic zone. The model was solved analytically and applied, using representative parameter ranges and values, to identify under which site conditions the attenuation of hydrocarbons migrating into indoor environments is likely to be significant. Simulations were performed assuming a soil contaminated by toluene only, by a BTEX mixture, by Fresh Gasoline and by Weathered Gasoline. The obtained results have shown that for several site conditions oxygen concentration below the building is sufficient to sustain aerobic biodegradation. For these scenarios the aerobic biodegradation is the primary mechanism of attenuation, i.e. anaerobic contribution is negligible and a model accounting just for aerobic biodegradation can be used. On the contrary, in all cases where oxygen is not sufficient to sustain aerobic biodegradation alone (e.g. highly contaminated sources), anaerobic biodegradation can significantly contribute to the overall attenuation depending on the site specific conditions.

  4. Modeling of vapor intrusion from hydrocarbon-contaminated sources accounting for aerobic and anaerobic biodegradation.

    PubMed

    Verginelli, Iason; Baciocchi, Renato

    2011-11-01

    A one-dimensional steady state vapor intrusion model including both anaerobic and oxygen-limited aerobic biodegradation was developed. The aerobic and anaerobic layer thickness are calculated by stoichiometrically coupling the reactive transport of vapors with oxygen transport and consumption. The model accounts for the different oxygen demand in the subsurface required to sustain the aerobic biodegradation of the compound(s) of concern and for the baseline soil oxygen respiration. In the case of anaerobic reaction under methanogenic conditions, the model accounts for the generation of methane which leads to a further oxygen demand, due to methane oxidation, in the aerobic zone. The model was solved analytically and applied, using representative parameter ranges and values, to identify under which site conditions the attenuation of hydrocarbons migrating into indoor environments is likely to be significant. Simulations were performed assuming a soil contaminated by toluene only, by a BTEX mixture, by Fresh Gasoline and by Weathered Gasoline. The obtained results have shown that for several site conditions oxygen concentration below the building is sufficient to sustain aerobic biodegradation. For these scenarios the aerobic biodegradation is the primary mechanism of attenuation, i.e. anaerobic contribution is negligible and a model accounting just for aerobic biodegradation can be used. On the contrary, in all cases where oxygen is not sufficient to sustain aerobic biodegradation alone (e.g. highly contaminated sources), anaerobic biodegradation can significantly contribute to the overall attenuation depending on the site specific conditions.

  5. Dynamic modeling of biodegradation and volatilization of hazardous aromatic substances in aerobic bioreactor.

    PubMed

    Mozo, I; Lesage, G; Yin, J; Bessiere, Y; Barna, L; Sperandio, M

    2012-10-15

    The aerobic biological process is one of the best technologies available for removing hazardous organic substances from industrial wastewaters. But in the case of volatile organic compounds (benzene, toluene, ethylbenzene, p-xylene, naphthalene), volatilization can contribute significantly to their removal from the liquid phase. One major issue is to predict the competition between volatilization and biodegradation in biological process depending on the target molecule. The aim of this study was to develop an integrated dynamic model to evaluate the influence of operating conditions, kinetic parameters and physical properties of the molecule on the main pathways (biodegradation and volatilization) for the removal of Volatile Organic Compounds (VOC). After a comparison with experimental data, sensitivity studies were carried out in order to optimize the aerated biological process. Acclimatized biomass growth is limited by volatilization, which reduces the bioavailability of the substrate. Moreover, the amount of biodegraded substrate is directly proportional to the amount of active biomass stabilized in the process. Model outputs predict that biodegradation is enhanced at high SRT for molecules with low H and with a high growth rate population. Air flow rate should be optimized to meet the oxygen demand and to minimize VOC stripping. Finally, the feeding strategy was found to be the most influential operating parameter that should be adjusted in order to enhance VOC biodegradation and to limit their volatilization in sequencing batch reactors (SBR).

  6. Removal of the anti-cancer drug methotrexate from water by advanced oxidation processes: Aerobic biodegradation and toxicity studies after treatment.

    PubMed

    Lutterbeck, Carlos Alexandre; Baginska, Ewelina; Machado, Ênio Leandro; Kümmerer, Klaus

    2015-12-01

    Anti-cancer drugs are discussed as high risk substances in regard to human health and considered as problematic for the environment. They are of potential environmental relevance due to their poor biodegradability and toxicological properties. Methotrexate (MTX) is an antimetabolite that was introduced in the pharmaceutical market in the 40's and still today is one of the most consumed cytotoxic compounds around the world. In the present study MTX was only partially biodegraded in the closed bottle test (CBT). Therefore, it was submitted to three different advanced oxidation processes (AOPs): UV/H2O2, UV/Fe(2+)/H2O2 and UV/TiO2. The irradiation was carried out with a Hg medium-pressure lamp during 256min whereas the analytical monitoring was done through LC-UV-MS/MS and DOC analysis. MTX was easily removed in all the irradiation experiments, while the highest mineralization values and rates were achieved by the UV/Fe(2+)/H2O2 treatment. The lowest resulted from the UV/H2O2 reactions. The UV/H2O2 treatment resulted in little biodegradable transformation products (TPs). However, the same treatment resulted in a reduction of the toxicity of MTX by forming less toxic TPs. Analysis by LC-UV-MS/MS revealed the existence of nine TPs formed during the photo-catalytic treatments. The pH of the solutions decreased from 6.4 (t 0min) to 5.15 in the UV/H2O2 and from 6.4 (t 0min) to 5.9 in the UV/TiO2 at the end of the experiments. The initial pH of the UV/Fe(2+)/H2O2 experiments was adjusted to 5 and after the addition of H2O2 the pH decreased to around 3 and remained in this range until the end of the treatments.

  7. Aerobic biodegradation of organic compounds in hydraulic fracturing fluids.

    PubMed

    Kekacs, Daniel; Drollette, Brian D; Brooker, Michael; Plata, Desiree L; Mouser, Paula J

    2015-07-01

    Little is known of the attenuation of chemical mixtures created for hydraulic fracturing within the natural environment. A synthetic hydraulic fracturing fluid was developed from disclosed industry formulas and produced for laboratory experiments using commercial additives in use by Marcellus shale field crews. The experiments employed an internationally accepted standard method (OECD 301A) to evaluate aerobic biodegradation potential of the fluid mixture by monitoring the removal of dissolved organic carbon (DOC) from an aqueous solution by activated sludge and lake water microbial consortia for two substrate concentrations and four salinities. Microbial degradation removed from 57 % to more than 90 % of added DOC within 6.5 days, with higher removal efficiency at more dilute concentrations and little difference in overall removal extent between sludge and lake microbe treatments. The alcohols isopropanol and octanol were degraded to levels below detection limits while the solvent acetone accumulated in biological treatments through time. Salinity concentrations of 40 g/L or more completely inhibited degradation during the first 6.5 days of incubation with the synthetic hydraulic fracturing fluid even though communities were pre-acclimated to salt. Initially diverse microbial communities became dominated by 16S rRNA sequences affiliated with Pseudomonas and other Pseudomonadaceae after incubation with the synthetic fracturing fluid, taxa which may be involved in acetone production. These data expand our understanding of constraints on the biodegradation potential of organic compounds in hydraulic fracturing fluids under aerobic conditions in the event that they are accidentally released to surface waters and shallow soils.

  8. Effects of Rate-Limited Mass Transfer on Modeling Vapor Intrusion with Aerobic Biodegradation.

    PubMed

    Chen, Yiming; Hou, Deyi; Lu, Chunhui; Spain, Jim C; Luo, Jian

    2016-09-06

    Most of the models for simulating vapor intrusion accept the local equilibrium assumption for multiphase concentration distributions, that is, concentrations in solid, liquid and vapor phases are in equilibrium. For simulating vapor transport with aerobic biodegradation controlled by counter-diffusion processes, the local equilibrium assumption combined with dual-Monod kinetics and biomass decay may yield near-instantaneous behavior at steady state. The present research investigates how predicted concentration profiles and fluxes change as interphase mass transfer resistances are increased for vapor intrusion with aerobic biodegradation. Our modeling results indicate that the attenuation coefficients for cases with and without mass transfer limitations can be significantly different by orders of magnitude. Rate-limited mass transfer may lead to larger overlaps of contaminant vapor and oxygen concentrations, which cannot be simulated by instantaneous reaction models with local equilibrium mass transfer. In addition, the contaminant flux with rate-limited mass transfer is much smaller than that with local equilibrium mass transfer, indicating that local equilibrium mass transfer assumption may significantly overestimate the biodegradation rate and capacity for mitigating vapor intrusion through the unsaturated zone. Our results indicate a strong research need for field tests to examine the validity of local equilibrium mass transfer, a widely accepted assumption in modeling vapor intrusion.

  9. Kinetics of the biodegradation of green table olive wastewaters by aerobic and anaerobic treatments.

    PubMed

    Beltran, J; Gonzalez, T; Garcia, J

    2008-06-15

    The biodegradation of the organic pollutant matter present in green table olive wastewater (GTOW) is studied in batch reactors by an aerobic biodegradation and by an anaerobic digestion. In the aerobic biodegradation, the evolution of the substrate (in terms of chemical and biochemical oxygen demand), biomass, and total polyphenolic compounds present in the wastewater are followed during the process, and a kinetic study is performed using Contois' model, which when applied to the experimental results provides the kinetic parameter of this model, resulting in a modified Contois' equation (q=3.3S/(0.31S(0)X+X), gCOD/gVSS d(-1)). Other kinetic parameters were determined: the cellular yield coefficient (YX/S=5.7x10(-2) gVSS/gCOD) and the kinetic constant of cellular death phase (kd=0.16 d(-1)). Similarly, in the anaerobic digestion, the evolution of the substrate digested and the methane produced are followed, and the kinetic study is conducted using a modified Monod model combined with the Levenspiel model, due to the presence of inhibition effects. This model leads to the determination of the kinetic parameters: kinetic constant when no inhibitory substance is present (kM0=8.4x10(-2) h(-1)), critical substrate concentration of inhibition (TP*=0.34 g/L) and inhibitory parameter (n=2.25).

  10. Aerobic biodegradation of amines in industrial saline wastewaters.

    PubMed

    Campo, Pablo; Platten, William; Suidan, Makram T; Chai, Yunzhou; Davis, John W

    2011-11-01

    The treatment of hypersaline wastewaters represents a challenge since high salt concentrations disrupt bacteria present in normal biological treatments. This study was conducted to determine the fate of amines in two hypersaline wastewaters obtained from an industrial treatment plant processing influents with 3% and 7% of NaCl. The compounds were aniline (ANL), 4,4'-methylenedianiline (4,4'-MDA), cyclohexylamine (CHA), N-(2-aminoethyl)ethanolamine (AEA), N,N-diethylethanolamine (DEA), N,N-bis(2-hydroxyethyl)methylamine (MDEA), and tris(2-hydroxyethyl)amine (TEA). Mixtures of these chemicals with a mixed liquor suspended solids concentration of 1000 mg L(-1) were prepared at two salinities (3% and 7% NaCl). Ethanolamines were readily biodegraded at both salinities, following first-order kinetics with half-lives ranging between 10 and 58 h. Hydroxyl groups present in the ethanolamines had a positive impact on the biodegradation. Salinity did not affect the biodegradation rate of TEA and MDEA, whereas AEA and DEA degraded faster in 3% NaCl. After 48h, CHA was metabolized within a 24-h period in 3% NaCl, while no degradation was observed in 7% NaCl. ANL exhibited lag phases in both salinities and, in the following 24-h period, ANL concentrations dropped 40% and disappeared after 48 h. 4,4'-MDA degraded in 3% NaCl (half-life of 123 h) and remained unaltered after 120 h in 7% NaCl.

  11. Quantification of aerobic biodegradation and volatilization rates of gasoline hydrocarbons near the water table under natural attenuation conditions

    USGS Publications Warehouse

    Lahvis, M.A.; Baehr, A.L.; Baker, R.J.

    1999-01-01

    Aerobic biodegradation and volatilization near the water table constitute a coupled pathway that contributes significantly to the natural attenuation of hydrocarbons at gasoline spill sites. Rates of hydrocarbon biodegradation and volatilization were quantified by analyzing vapor transport in the unsaturated zone at a gasoline spill site in Beaufort, South Carolina. Aerobic biodegradation rates decreased with distance above the water table, ranging from 0.20 to 1.5g m-3 d-1 for toluene, from 0.24 to 0.38 g m-3 d-1 for xylene, from 0.09 to 0.24 g m-3 d-1 for cyclohexene, from 0.05 to 0.22 g m-3 d-1 for ethylbenzene, and from 0.02 to 0.08 g m-3 d-1 for benzene. Rates were highest in the capillary zone, where 68% of the total hydrocarbon mass that volatilized from the water table was estimated to have been biodegraded. Hydrocarbons were nearly completely degraded within 1 m above the water table. This large loss underscores the importance of aerobic biodegradation in limiting the transport of hydrocarbon vapors in the unsaturated zone and implies that vapor-plume migration to basements and other points of contact may only be significant if a source of free product is present. Furthermore, because transport of the hydrocarbon in the unsaturated zone can be limited relative to that of oxygen and carbon dioxide, soil, gas surveys conducted at hydrocarbon-spill sites would benefit by the inclusion of oxygen- and carbon-dioxide-gas concentration measurements. Aerobic degradation kinetics in the unsaturated zone were approximately first-order. First-order rate constants near the water table were highest for cyctohexene (0.21-0.65 d-1) and nearly equivalent for ethylbenzene (0.11-20.31 d-1), xylenes (0.10-0.31 d-1), toluene (0.09-0.30 d-1), and benzene (0.07,0.31 d-1). Hydrocarbon mass loss rates at the water table resulting from the coupled aerobic biodegradation and volatilization process were determined by extrapolating gas transport rates through the capillary zone. Mass

  12. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    USGS Publications Warehouse

    Lahvis, M.A.; Baehr, A.L.

    1996-01-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 g yr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 g m-2 yr-1 (1.45 x 10-3 and 1.51 x 10-3 gal. ft.-2 yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  13. Estimation of rates of aerobic hydrocarbon biodegradation by simulation of gas transport in the unsaturated zone

    NASA Astrophysics Data System (ADS)

    Lahvis, Matthew A.; Baehr, Arthur L.

    1996-07-01

    The distribution of oxygen and carbon dioxide gases in the unsaturated zone provides a geochemical signature of aerobic hydrocarbon degradation at petroleum product spill sites. The fluxes of these gases are proportional to the rate of aerobic biodegradation and are quantified by calibrating a mathematical transport model to the oxygen and carbon dioxide gas concentration data. Reaction stoichiometry is assumed to convert the gas fluxes to a corresponding rate of hydrocarbon degradation. The method is applied at a gasoline spill site in Galloway Township, New Jersey, to determine the rate of aerobic degradation of hydrocarbons associated with passive and bioventing remediation field experiments. At the site, microbial degradation of hydrocarbons near the water table limits the migration of hydrocarbon solutes in groundwater and prevents hydrocarbon volatilization into the unsaturated zone. In the passive remediation experiment a site-wide degradation rate estimate of 34,400 gyr-1 (11.7 gal. yr-1) of hydrocarbon was obtained by model calibration to carbon dioxide gas concentration data collected in December 1989. In the bioventing experiment, degradation rate estimates of 46.0 and 47.9 gm-2yr-1 (1.45×10-3 and 1.51×10-3 gal.ft.-2yr-1) of hydrocarbon were obtained by model calibration to oxygen and carbon dioxide gas concentration data, respectively. Method application was successful in quantifying the significance of a naturally occurring process that can effectively contribute to plume stabilization.

  14. Effects of exogenous aerobic bacteria on methane production and biodegradation of municipal solid waste in bioreactors.

    PubMed

    Ge, Sai; Liu, Lei; Xue, Qiang; Yuan, Zhiming

    2016-09-01

    Landfill is the most common and efficient ways of municipal solid waste (MSW) disposal and the landfill biogas, mostly methane, is currently utilized to generate electricity and heat. The aim of this work is to study the effects and the role of exogenous aerobic bacteria mixture (EABM) on methane production and biodegradation of MSW in bioreactors. The results showed that the addition of EABM could effectively enhance hydrolysis and acidogenesis processes of MSW degradation, resulting in 63.95% reduction of volatile solid (VS), the highest methane production rate (89.83Lkg(-1) organic matter) ever recorded and a threefold increase in accumulative methane production (362.9L) than the control (127.1L). In addition, it is demonstrated that white-rot fungi (WRF) might further promote the methane production through highly decomposing lignin, but the lower pH value in leachate and longer acidogenesis duration may cause methane production reduced. The data demonstrated that methane production and biodegradation of MSW in bioreactors could be significantly enhanced by EABM via enhanced hydrolysis and acidogenesis processes, and the results are of great economic importance for the future design and management of landfill.

  15. AEROBIC SOIL MICROCOSMS FOR LONG-TERM BIODEGRADATION OF HYDROCARBON VAPORS

    EPA Science Inventory

    The aims of this research project included the development of laboratory protocols for the preparation of aerobic soil microcosms using aseptic field soil samples, and for the gas chromatographic analysis of hydrocarbon vapor biodegradation based on vapor samples obtained from th...

  16. BIODEGRADATION KINETICS AND TOXICITY OF VEGETABLE OIL TRIACYLGLYCEROLS UNDER AEROBIC CONDITIONS

    EPA Science Inventory

    The aerobic biodegradation of five triacylglycerols (TAGs), three liquids [triolein (OOO), trilinolein (LLL), and trilinolenin (LnLnLn)] and two solids [tripalmitin (PPP) and tristearin (SSS)] was studied in water. Respirometry tests were designed and conducted to determine the b...

  17. Aerobic Biodegradation Kinetics And Mineralization Of Six Petrodiesel/Soybean-Biodiesel Blends

    EPA Science Inventory

    The aerobic biodegradation kinetics and mineralization of six petrodiesel/soybean-biodiesel blends (B0, B20, B40, B60, B80, and B100), where B100 is 100% biodiesel, were investigated by acclimated cultures. The fatty acid methyl esters (FAMEs) of biodiesel were found to undergo ...

  18. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... released to aquatic environments. A high biodegradability result in this test provides evidence that the... measure the amount of CO2 evolved. Differences in the extent of DOC disappearance and CO2 evolution... Erlenmeyer flask. EC01AP92.039 Figure 1—Shake-Flask System for Carbon Dioxide Evolution The Ba(OH)2...

  19. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... released to aquatic environments. A high biodegradability result in this test provides evidence that the... measure the amount of CO2 evolved. Differences in the extent of DOC disappearance and CO2 evolution... Erlenmeyer flask. EC01AP92.039 Figure 1—Shake-Flask System for Carbon Dioxide Evolution The Ba(OH)2...

  20. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... released to aquatic environments. A high biodegradability result in this test provides evidence that the... measure the amount of CO2 evolved. Differences in the extent of DOC disappearance and CO2 evolution... Erlenmeyer flask. EC01AP92.039 Figure 1—Shake-Flask System for Carbon Dioxide Evolution The Ba(OH)2...

  1. COMPARISON OF FIELD AEROBIC BIODEGRADATION RATES TO LABORATORY

    EPA Science Inventory

    It is common to use bioventing as a polishing step for soil vapor extraction. It was originally planned to use soil vapor extraction and bioventing at a former landfill site in Delaware but laboratory scale biodegradation studies indicated that most of the volatile organic compou...

  2. AEROBIC BIODEGRADATION OF GASOLINE OXYGENATES MTBE AND TBA

    EPA Science Inventory

    MTBE degradation was investigated using a continuously stirred tank reactor (CSTR) with biomass retention (porous pot reactor) operated under aerobic conditions. MTBE was fed to the reactor at an influent concentration of 150 mg/l (1.70 mmol/l). A second identifical rector was op...

  3. ANAEROBIC/AEROBIC BIODEGRADATION OF PENTACHLOROPHENOL USING GAC FLUIDIXED BED REACTORS: OPTIMIZATION OF THE EMPTY BED CONTACT TIME

    EPA Science Inventory

    An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to approximately equimolar concentrations (>99%) of chlorophenol (CP) in a granular activa...

  4. A comparison of the effects of two methods of acclimation of aerobic biodegradability

    SciTech Connect

    Watson, H.M. . Environmental Sciences Section)

    1993-11-01

    The acclimation or adaptation of microorganisms to organic chemicals is an important factor influencing both the rate and the extent of biodegradation. In this study two acclimation procedures were evaluated in terms of their effectiveness in enhancing biodegradation, their relative ease of use in the laboratory, and the implications for biodegradability testing. In the single-flask procedure, microorganisms were acclimated for 2 to 7 d in a single acclimation flask at constant or increasing concentrations of the test chemical without transfer of microorganisms. In the second procedure, the enrichment procedure, microorganisms were acclimated in a series of flasks over a 21-d period by making adaptive transfers to increasing concentrations of the test chemical. Acclimated microorganisms from each procedure were used as the source of inoculum for subsequent biodegradation tests in which carbon dioxide evolution was measured. Six chemicals were tested: quinoline, p-nitrophenol, N-methylaniline, N,N-dimethylaniline, acrylonitrile, and 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. Microorganisms acclimated in the single-flask procedure were much more effective than those acclimated in the enrichment procedure in degrading the test chemicals. The single-flask procedure is more convenient to use, and it permits monitoring of the time needed for acclimation. The results from these studies have implications for the methodology used in biodegradation test systems and suggest caution before adopting a multiple-flask, enrichment acclimation procedure before the performance of standardized tests for aerobic biodegradability.

  5. The degradability of biodegradable plastics in aerobic and anaerobic waste landfill model reactors.

    PubMed

    Ishigaki, Tomonori; Sugano, Wataru; Nakanishi, Akane; Tateda, Masafumi; Ike, Michihiko; Fujita, Masanori

    2004-01-01

    Degradabilities of four kinds of commercial biodegradable plastics (BPs), polyhydroxybutyrate and hydroxyvalerate (PHBV) plastic, polycaprolactone plastic (PCL), blend of starch and polyvinyl alcohol (SPVA) plastic and cellulose acetate (CA) plastic were investigated in waste landfill model reactors that were operated as anaerobically and aerobically. The application of forced aeration to the landfill reactor for supplying aerobic condition could potentially stimulate polymer-degrading microorganisms. However, the individual degradation behavior of BPs under the aerobic condition was completely different. PCL, a chemically synthesized BP, showed film breakage under the both conditions, which may have contributed to a reduction in the waste volume regardless of aerobic or anaerobic conditions. Effective degradation of PHBV plastic was observed in the aerobic condition, though insufficient degradation was observed in the anaerobic condition. But the aeration did not contribute much to accelerate the volume reduction of SPVA plastic and CA plastic. It could be said that the recalcitrant portions of the plastics such as polyvinyl alcohol in SPVA plastic and the highly substituted CA in CA plastic prevented the BP from degradation. These results indicated existence of the great variations in the degradability of BPs in aerobic and anaerobic waste landfills, and suggest that suitable technologies for managing the waste landfill must be combined with utilization of BPs in order to enhance the reduction of waste volume in landfill sites.

  6. Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater.

    PubMed

    Ulrich, Ania C; Guigard, Selma E; Foght, Julia M; Semple, Kathleen M; Pooley, Kathryn; Armstrong, James E; Biggar, Kevin W

    2009-02-01

    Hydrocarbon-contaminated soil and groundwater at oil and gas production sites may be additionally impacted by salts due to release of produced waters. However, little is known about the effect of salt on the in-situ biodegradation of hydrocarbons by terrestrial microbes, especially at low temperatures. To study this effect, we prepared a groundwater-soil slurry from two sites in Canada: a former flare pit site contaminated with flare pit residue (Site A), and a natural gas processing facility contaminated with natural gas condensate (Site B). The slurry with its indigenous microbes was amended with radiolabeled hydrocarbons dissolved in free product plus nutrients and/or NaCl, and incubated in aerobic biometer flasks with gyrotory shaking at either 25 or 10 degrees C for up to 5 weeks. Cumulative production of (14)CO(2) was measured and the lag time, rate and extent of mineralization were calculated. For Site A, concentrations of NaCl >or=1% (w/v) delayed the onset of mineralization of both (14)C-hexadecane and (14)C-phenanthrene under nutrient-amended conditions, but once biodegradation began the degradation rates were similar over the range of salt concentrations tested (0-5% NaCl). For Site B, increasing concentrations of NaCl >or=1% (w/v) increased the lag time and decreased the rate and extent of mineralization of aliphatic and aromatic substrates. Of particular interest is the observation that low concentrations of salt (

  7. Hydrogen Isotope Fractionation As a Tool to Identify Aerobic and Anaerobic PAH Biodegradation.

    PubMed

    Kümmel, Steffen; Starke, Robert; Chen, Gao; Musat, Florin; Richnow, Hans H; Vogt, Carsten

    2016-03-15

    Aerobic and anaerobic polycyclic aromatic hydrocarbon (PAH) biodegradation was characterized by compound specific stable isotope analysis (CSIA) of the carbon and hydrogen isotope effects of the enzymatic reactions initiating specific degradation pathways, using naphthalene and 2-methylnaphtalene as model compounds. Aerobic activation of naphthalene and 2-methylnaphthalene by Pseudomonas putida NCIB 9816 and Pseudomonas fluorescens ATCC 17483 containing naphthalene dioxygenases was associated with moderate carbon isotope fractionation (εC = -0.8 ± 0.1‰ to -1.6 ± 0.2‰). In contrast, anaerobic activation of naphthalene by a carboxylation-like mechanism by strain NaphS6 was linked to negligible carbon isotope fractionation (εC = -0.2 ± 0.2‰ to -0.4 ± 0.3‰). Notably, anaerobic activation of naphthalene by strain NaphS6 exhibited a normal hydrogen isotope fractionation (εH = -11 ± 2‰ to -47 ± 4‰), whereas an inverse hydrogen isotope fractionation was observed for the aerobic strains (εH = +15 ± 2‰ to +71 ± 6‰). Additionally, isotope fractionation of NaphS6 was determined in an overlaying hydrophobic carrier phase, resulting in more reliable enrichment factors compared to immobilizing the PAHs on the bottle walls without carrier phase. The observed differences especially in hydrogen fractionation might be used to differentiate between aerobic and anaerobic naphthalene and 2-methylnaphthalene biodegradation pathways at PAH-contaminated field sites.

  8. Biodegradation of o-nitrophenol by aerobic granules with glucose as co-substrate.

    PubMed

    Basheer, Farrukh; Isa, M H; Farooqi, I H

    2012-01-01

    Aerobic granules to treat wastewater containing o-nitrophenol were successfully developed in a sequencing batch reactor (SBR) using activated sludge as inoculum. Stable aerobic granules were obtained with a clearly defined shape and diameters ranging from 2 to 6 mm after 122 days of operation. The integrity coefficient (IC) and granules density was found to be 98% and 1,054 kg m(-3) respectively. After development of aerobic granules, o-nitrophenols were successfully degraded to an efficiency of 78% at a concentration of 70 mg L(-1). GC-MS study revealed that the biodegradation of o-nitrophenol occurred via catechol via nitrobenzene pathway. Specific o-nitrophenol biodegradation rates followed the Haldane model and the associated kinetic parameters were found as follows: V(max) = 3.96 g o-nitrophenol g(-1)VSS(-1)d(-1), K(s) = 198.12 mg L(-1), and K(i) = 31.16 mg L(-1). The aerobic granules proved to be a feasible and effective way to degrade o-nitrophenol containing wastewater.

  9. Two-Dimensional Stable Isotope Fractionation During Aerobic and Anaerobic Alkane Biodegradation and Implications for the Field

    NASA Astrophysics Data System (ADS)

    El Morris, Brandon; Suflita, Joseph M.; Richnow, Hans-Hermann

    2010-05-01

    Quantitatively, n-alkanes comprise a major portion of most crude oils. In petroliferous formations, it may be possible to relate the loss of these compounds to the levels of biodegradation occurring in situ [1]. Moreover, it is important to develop indicators of alkane degradation that may be used to monitor bioremediation of hydrocarbon-impacted environments. Desulfoglaeba alkanexedens and Pseudomonas putida GPo1 were used to determine if carbon and hydrogen stable isotope fractionation could differentiate between n-alkane degradation under anaerobic and aerobic conditions, respectively in the context of the Rayleigh equation model [2]. Bacterial cultures were sacrificed by acidification and headspace samples were analyzed for stable isotope composition using gas chromatography-isotope ratio mass spectrometry. Carbon enrichment factors (bulk) for anaerobic and aerobic biodegradation of hexane were -5.52 ± 0.2‰ and -4.34 ± 0.3‰, respectively. Hydrogen enrichment during hexane degradation was -43.14 ± 6.32‰ under sulfate-reducing conditions, and was too low for quantification during aerobiosis. Collectively, this indicates that the correlation between carbon and hydrogen stable isotope fractionation (may be used to help elucidate in situ microbial processes in oil reservoirs, and during intrinsic as well as engineered remediation efforts. References 1. Asif, M.; Grice, K.; Fazeelat, T., Assessment of petroleum biodegradation using stable hydrogen isotopes of individual saturated hydrocarbon and polycyclic aromatic hydrocarbon distributions in oils from the Upper Indus Basin, Pakistan. Organic Geochemistry 2009, 40, (3), 301-311. 2. Fischer, A.; Herklotz, I.; Herrmann, S.; Thullner, M.; Weelink, S. A. B.; Stams, A., J. M.; Schloemann, M.; Richnow, H.-H.; Vogt, C., Combined carbon and hydrogen isotope fractionation investigations for elucidating benzene biodegradation pathways. Environ. Sci. Technol. 2008, 42, 4356-4363.

  10. Aerobic biodegradation of propylene glycol by soil bacteria.

    PubMed

    Toscano, Giuseppe; Cavalca, Lucia; Letizia Colarieti, M; Scelza, Rosalia; Scotti, Riccardo; Rao, Maria A; Andreoni, Vincenza; Ciccazzo, Sonia; Greco, Guido

    2013-09-01

    Propylene glycol (PG) is a main component of aircraft deicing fluids and its extensive use in Northern airports is a source of soil and groundwater contamination. Bacterial consortia able to grow on PG as sole carbon and energy source were selected from soil samples taken along the runways of Oslo Airport Gardermoen site (Norway). DGGE analysis of enrichment cultures showed that PG-degrading populations were mainly composed by Pseudomonas species, although Bacteroidetes were found, as well. Nineteen bacterial strains, able to grow on PG as sole carbon and energy source, were isolated and identified as different Pseudomonas species. Maximum specific growth rate of mixed cultures in the absence of nutrient limitation was 0.014 h(-1) at 4 °C. Substrate C:N:P molar ratios calculated on the basis of measured growth yields are in good agreement with the suggested values for biostimulation reported in literature. Therefore, the addition of nutrients is suggested as a suitable technique to sustain PG aerobic degradation at the maximum rate by autochthonous microorganisms of unsaturated soil profile.

  11. Design and construction of a medium-scale automated direct measurement respirometric system to assess aerobic biodegradation of polymers

    NASA Astrophysics Data System (ADS)

    Castro Aguirre, Edgar

    A medium-scale automated direct measurement respirometric (DMR) system was designed and built to assess the aerobic biodegradation of up to 30 materials in triplicate simultaneously. Likewise, a computer application was developed for rapid analysis of the data generated. The developed DMR system was able to simulate different testing conditions by varying temperature and relative humidity, which are the major exposure conditions affecting biodegradation. Two complete tests for determining the aerobic biodegradation of polymers under composting conditions were performed to show the efficacy and efficiency of both the DMR system and the DMR data analyzer. In both cases, cellulose reached 70% mineralization at 139 and 45 days. The difference in time for cellulose to reach 70% mineralization was attributed to the composition of the compost and water availability, which highly affect the biodegradation rate. Finally, among the tested materials, at least 60% of the organic carbon content of the biodegradable polymers was converted into carbon dioxide by the end of the test.

  12. Biodegradation and kinetics of aerobic granules under high organic loading rates in sequencing batch reactor.

    PubMed

    Chen, Yao; Jiang, Wenju; Liang, David Tee; Tay, Joo Hwa

    2008-05-01

    Biodegradation, kinetics, and microbial diversity of aerobic granules were investigated under a high range of organic loading rate 6.0 to 12.0 kg chemical oxygen demand (COD) m(-3) day(-1) in a sequencing batch reactor. The selection and enriching of different bacterial species under different organic loading rates had an important effect on the characteristics and performance of the mature aerobic granules and caused the difference on granular biodegradation and kinetic behaviors. Good granular characteristics and performance were presented at steady state under various organic loading rates. Larger and denser aerobic granules were developed and stabilized at relatively higher organic loading rates with decreased bioactivity in terms of specific oxygen utilization rate and specific growth rate (muoverall) or solid retention time. The decrease of bioactivity was helpful to maintain granule stability under high organic loading rates and improve reactor operation. The corresponding biokinetic coefficients of endogenous decay rate (kd), observed yield (Yobs), and theoretical yield (Y) were measured and calculated in this study. As the increase of organic loading rate, a decreased net sludge production (Yobs) is associated with an increased solid retention time, while kd and Y changed insignificantly and can be regarded as constants under different organic loading rates.

  13. Effects of randomly methylated-beta-cyclodextrins (RAMEB) on the bioavailability and aerobic biodegradation of polychlorinated biphenyls in three pristine soils spiked with a transformer oil.

    PubMed

    Fava, F; Ciccotosto, V F

    2002-03-01

    The low bioavailability of polychlorinated biphenyls (PCBs) in soils often results in their slow and partial aerobic biodegradation. The process can be enhanced by supplementing soils with cyclodextrins. However, pure cyclodextrins are expensive and we have therefore explored the use of a less costly technical grade mixture of randomly methylated-beta-cyclodextrins (RAMEB). RAMEB was tested at 0, 1, 3 and 5% (w/w) in the aerobic bioremediation and detoxification of a loamy-, a humic- and a sandy-soil, each artificially contaminated with a PCB-containing transformer oil (added PCBs: about 450 or 700 mg/kg), inoculated with an exogenous aerobic PCB-biodegrading bacterial co-culture and treated in slurry- and solid-phase laboratory conditions. Significant depletions of the spiked PCBs were observed in all microcosms of the three soils after 90 days of treatment; however, interesting yields of PCB dechlorination and detectable decreases of the original soil ecotoxicity were observed in the slurry-phase microcosms. RAMEB generally enhanced PCB-metabolism with effects which were dependent on the concentration at which it was applied, the physical-chemical nature of the amended soil, and the soil treatment conditions employed. RAMEB, which was slowly metabolized by soil microorganisms, enhanced the presence of PCBs and PCB-cometabolizing bacteria in the soil-water phase, suggesting that RAMEB enhances aerobic biodegradation of PCBs by increasing pollutant bioavailability in soil microcosms.

  14. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... help to put toxic effects into perspective. (2) Definitions. (i) “Adaptation” is the process by which a... inoculum, including source, collection date, handling, storage and adaptation possibilities (i.e., that...

  15. 40 CFR 796.3100 - Aerobic aquatic biodegradation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... help to put toxic effects into perspective. (2) Definitions. (i) “Adaptation” is the process by which a... inoculum, including source, collection date, handling, storage and adaptation possibilities (i.e., that...

  16. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil

    SciTech Connect

    Hinchee, R.E.; Ong, S.K. )

    1992-10-01

    A in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O[sub 2]) and production of carbon dioxide (CO[sub 2]) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O[sub 2]/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O[sub 2] utilization were generally more reliable (especially for alkaline soils) than rates based on CO[sub 2] production, CO[sub 2] produced from microbial respiration was probably converted to carbonate under alkaline conditions. 14 refs., 5 figs., 4 tabs.

  17. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil.

    PubMed

    Hinchee, R E; Ong, S K

    1992-10-01

    An in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O2) and production of carbon dioxide (CO2) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O2/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O2 utilization were generally more reliable (especially for alkaline soils) than rates based on CO2 production. CO2 produced from microbial respiration was probably converted to carbonate under alkaline conditions.

  18. Simulating the effect of aerobic biodegradation on soil vapor intrusion into buildings: influence of degradation rate, source concentration, and depth.

    PubMed

    Abreu, Lilian D V; Johnson, Paul C

    2006-04-01

    Steady-state vapor intrusion scenarios involving aerobically biodegradable chemicals are studied using a three-dimensional multicomponent numerical model. In these scenarios, sources of aerobically biodegradable chemical vapors are placed at depths of 1-14 m beneath a 10 m x 10 m basement or slab-on-grade construction building, and the simultaneous transport and reaction of hydrocarbon and oxygen vapors are simulated. The results are presented as Johnson and Ettinger attenuation factors alpha (predicted indoor air hydrocarbon concentration/source vapor concentration), and normalized contour plots of hydrocarbon and oxygen concentrations. In addition to varying the vapor source depth, the effects of source concentration (2-200 mg chemical/L vapor) and oxygen-limited first-order reaction rates (0.018-1.8 h(-1)) are studied. Hydrocarbon inputs were specific to benzene, although the relevant properties are similar to those for a range of hydrocarbons of interest. Overall, the results suggest that aerobic biodegradation could play a significant role in reducing vapor intrusion into buildings (decreased alpha-values) relative to the no-biodegradation case, with the significance of aerobic biodegradation increasing with increasing vapor source depth, decreasing vapor source concentration, and increasing first-order biodegradation rate. In contrast to the no-biodegradation case, differences in foundation construction can be significant in some settings. The significance of aerobic biodegradation is directly related to the extent to which oxygen is capable of migrating beneath the foundation. For example, in the case of a basement scenario with a 200 mg/L vapor source located at 3 m bgs, oxygen is consumed before it can migrate beneath the foundation, so the attenuation factors for simulations with and without aerobic biodegradation are similar for all first-order rates studied. For the case of a 2 mg/L vapor source located at 8 m bgs, the oxygen is widely distributed

  19. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    PubMed

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided.

  20. Ozone oxidation and aerobic biodegradation with spent mushroom compost for detoxification and benzo(a)pyrene removal from contaminated soil.

    PubMed

    Russo, Lara; Rizzo, Luigi; Belgiorno, Vincenzo

    2012-05-01

    The combination of ozonation and spent mushroom compost (SMC)-mediated aerobic biological treatment was investigated in the removal of benzo(a)pyrene from contaminated soil. The performances of the process alone and combined were evaluated in terms of benzo(a)pyrene removal efficiency, mineralization efficiency (as total organic carbon removal), and soil residual toxicity (phytotoxicity to Lepidium Sativum and toxicity to Vibrio fischeri). In spite of the removal efficiency (35%) obtained by SMC-mediated biological process as a stand-alone treatment, the combined process showed a benzo(a)pyrene concentration reduction higher than 75%; the best removal (82%) was observed after 10 min pre-ozonation treatment. In particular, ozonation improved the biodegradability of the contaminant, as confirmed by the increase of CO(2) production (close to 70% compared to the control), mineralization (greater than 60%) and bacterial density (which increased by two orders of magnitude). Moreover, according to phytotoxicity tests on L. Sativum, the aerobic biological process of pre-ozonated soil decreased toxicity. According to the results achieved in the present study, ozonation pre-treatment showed an high potential to overcome the limitation of bioremediation of recalcitrant compound, but it should be carefully operated in order to maximize PAH removal efficiency as well as to minimize soil residual toxicity which can result from the formation of the oxidation intermediates.

  1. Hydrocarbon Specificity During Aerobic oil Biodegradation Revealed in Marine Microcosms With the use of Comprehensive, Two-Dimensional Gas Chromatography.

    NASA Astrophysics Data System (ADS)

    Wardlaw, G. D.; Reddy, C. M.; Nelson, R. K.; Valentine, D. L.

    2008-12-01

    In 2003 the National Research Council reported more than 380 million gallons of oil is emitted into the ocean each year from natural seepage and as a result of anthropogenic activities. Many of the hydrocarbons making up this oil are persistent and toxic to marine life. Petroleum emitted into biologically sensitive areas can lead to environmental stress and ecosystem collapse. As a result many studies and a substantial amount of resources have been devoted to creating efficient and effective remediation tools and developing a better understanding of natural hydrocarbon weathering processes occurring in marine environments. The goal of this study is to elucidate patterns and extent of aerobic hydrocarbon degradation in marine sediments. In order to assess the specific molecular transformations occurring in petroleum emitted into oxic marine environments, we prepared microcosm experiments using sediments and seawater collected from the natural oil seeps offshore Coal Oil Point, California. Petroleum recovered from Platform Holly in the Santa Barbara Channel, was added to a sediment-seawater mixture and the microcosm bottles were allowed to incubate under aerobic conditions for slightly more than 100 days. Comprehensive, two-dimensional gas chromatography was employed in this study to quantify changes in the concentrations of individual hydrocarbon compounds because of the increased resolution and resolving power provided with this robust analytical method. We show significant hydrocarbon mass loss due to aerobic biodegradation for hundreds of tracked compounds in the microcosm bottles. The results shown here provide quantitative evidence for broad-scale metabolic specificity during aerobic hydrocarbon degradation in surface and shallow subsurface marine sediments.

  2. Process Improvements: Aerobic Food Waste Composting at ISF Academy

    NASA Astrophysics Data System (ADS)

    Lau, Y. K.

    2015-12-01

    ISF Academy, a school with 1500 students in Hong Kong, installed an aerobic food waste composting system in November of 2013. The system has been operational for over seven months; we will be making improvements to the system to ensure the continued operational viability and quality of the compost. As a school we are committed to reducing our carbon footprint and the amount of waste we send to the local landfill. Over an academic year we produce approximately 27 metric tons of food waste. Our system processes the food waste to compost in 14 days and the compost is used by our primary school students in a organic farming project.There are two areas of improvement: a) if the composting system becomes anaerobic, there is an odor problem that is noticed by the school community; we will be testing the use of a bio-filter to eliminate the odor problem and, b) we will be working with an equipment vendor from Australia to install an improved grease trap system. The grease and oil that is collected will be sold to a local company here in Hong Kong that processes used cooking oil for making biofuels. This system will include a two stage filtration system and a heated vessel for separating the oil from the waste water.The third project will be to evaluate biodegradable cutlery for the compositing in the system. Currently, we use a significant quantity of non-biodegradable cutlery that is then thrown away after one use. Several local HK companies are selling biodegradable cutlery, but we need to evaluate the different products to determine which ones will work with our composting system. The food waste composting project at ISF Academy demonstrates the commitment of the school community to a greener environment for HK, the above listed projects will improve the operation of the system.

  3. Aerobic biodegradation potential of subsurface microorganisms from a jet fuel-contaminated aquifer

    USGS Publications Warehouse

    Aelion, C.M.; Bradley, P.M.

    1991-01-01

    In 1975, a leak of 83,000 gallons (314,189 liters) of jet fuel (JP-4) contaminated a shallow water-table aquifer near North Charleston, S.C. Laboratory experiments were conducted with contaminated sediments to assess the aerobic biodegradation potential of the in situ microbial community. Sediments were incubated with 14C-labeled organic compounds, and the evolution of 14CO2 was measured over time. Gas chromatographic analyses were used to monitor CO2 production and O2 consumption under aerobic conditions. Results indicated that the microbes from contaminated sediments remained active despite the potentially toxic effects of JP-4. 14CO2 was measured from [14C]glucose respiration in unamended and nitrate-amended samples after 1 day of incubation. Total [14C]glucose metabolism was greater in 1 mM nitrate-amended than in unamended samples because of increased cellular incorporation of 14C label. [14C]benzene and [14C]toluene were not significantly respired after 3 months of incubation. With the addition of 1 mM NO3, CO2 production measured by gas chromatographic analysis increased linearly during 2 months of incubation at a rate of 0.099 ??mol g-1 (dry weight) day-1 while oxygen concentration decreased at a rate of 0.124 ??mol g-1 (dry weight) day-1. With no added nitrate, CO2 production was not different from that in metabolically inhibited control vials. From the examination of selected components of JP-4, the n-alkane hexane appeared to be degraded as opposed to the branched alkanes of similar molecular weight. The results suggest that the in situ microbial community is active despite the JP-4 jet fuel contamination and that biodegradation may be compound specific. Also, the community is strongly nitrogen limited, and nitrogen additions may be required to significantly enhance hydrocarbon biodegradation.

  4. Aerobic biodegradation kinetics of solid organic wastes on earth and for applications in space

    NASA Astrophysics Data System (ADS)

    Ramirez Perez, Javier Christian

    Aerobic biodegradation plays an important role in recycling organic matter and nutrients on earth. It is also a candidate technology for waste processing and resource recovery in Advanced Life Support (ALS) systems, such as a proposed planetary base on Mars. Important questions are how long should wastes be treated, and what is the quality (stability/maturity) of the product. To address these questions two aerobic composting systems were evaluated. One treated (252 days) horse manure and cranberry fruit in duplicate open windrows (HCC) as a reference earth application. The other was a pilot-scale (330 L) enclosed, in-vessel system treating (162 days) inedible biomass collected from plant growth systems at NASA, amended with food and human wastes simulant for potential space application (ALSC). Samples were taken from both systems over time and product quality assessed with a range of physical, chemical, biological, toxicological, respirometry and plant growth analyses that were developed and standardized. Because plant growth analyses take so long, a hypothesis was that some parameters could be used to predict compost quality and suitability for growing plants. Maximum temperatures in the thermophilic range were maintained for both systems (HCC > 60°C for >129 days, ALSC > 55°C for >40 days. Fecal streptococci were reduced by 4.8 log-units for HCC and 7.8 for ALSC. Volume/mass reductions achieved were 63%/62% for HCC and 79%/67% for ALSC. Phytotoxicity tests performed on aqueous extracts to recover plant nutrients found decreasing sensitivity: arabidopsis > lettuce > tomato > wheat > cucumber, corresponding with seed size and food reserve capacity. The germination index (GI) of HCC increased over composting time indicating decreasing phytotoxicity. However, GIs for ALSC leachate decreased or fluctuated over composting time. Selected samples of HCC at 31, 157 and 252 days alone and combined with promix (1:1), and of ALSC at 7, 14, 21, 28, 40 and 84 days, or fresh

  5. Multiple lines of evidence to demonstrate vinyl chloride aerobic biodegradation in the vadose zone, and factors controlling rates

    NASA Astrophysics Data System (ADS)

    Patterson, B. M.; Aravena, R.; Davis, G. B.; Furness, A. J.; Bastow, T. P.; Bouchard, D.

    2013-10-01

    A field-based investigation was conducted at a contaminated site where the vadose zone was contaminated with a range of chlorinated hydrocarbons. The investigation consisted of groundwater and multilevel soil-gas monitoring of a range of contaminants and gases, along with isotope measurements and microbiology studies. The investigation provided multiple lines of evidence that demonstrated aerobic biodegradation of vinyl chloride (VC) was occurring in the vadose zone (i) above the on-site source zone, and (ii) above the downgradient off-site groundwater plume location. Data from both the on-site and off-site locations were consistent in showing substantially greater (an order of magnitude greater) rates of VC removal from the aerobic vadose zone compared to more recalcitrant contaminants trichloroethene (TCE) and tetrachloroethene (PCE). Soil gas VC isotope analysis showed substantial isotopic enrichment of VC (δ13C - 5.2 to - 10.9‰) compared to groundwater (δ13C - 39.5‰) at the on-site location. Soil gas CO2 isotope analysis at both locations showed that CO2 was highly isotopically depleted (δ13C - 28.8 to - 33.3‰), compared to soil gas CO2 data originating from natural sediment organic matter (δ13C = - 14.7 to - 21.3‰). The soil gas CO2 δ13C values were consistent with near-water table VC groundwater δ13C values (- 36.8 to - 39.5‰), suggesting CO2 originating from aerobic biodegradation of VC. Bacteria that had functional genes (ethene monooxygenase (etnC) and epoxyalkane transferase (etnE) involved in ethene metabolism and VC oxidation were more abundant at the source zone where oxygen co-existed with VC. The distribution of VC and oxygen vadose zone vapour plumes, together with long-term changes in soil gas CO2 concentrations and temperature, provided information to elucidate the factors controlling aerobic biodegradation of VC in the vadose zone. Based on the overlapping VC and oxygen vadose zone vapour plumes, aerobic vapour biodegradation

  6. Multiple lines of evidence to demonstrate vinyl chloride aerobic biodegradation in the vadose zone, and factors controlling rates.

    PubMed

    Patterson, B M; Aravena, R; Davis, G B; Furness, A J; Bastow, T P; Bouchard, D

    2013-10-01

    A field-based investigation was conducted at a contaminated site where the vadose zone was contaminated with a range of chlorinated hydrocarbons. The investigation consisted of groundwater and multilevel soil-gas monitoring of a range of contaminants and gases, along with isotope measurements and microbiology studies. The investigation provided multiple lines of evidence that demonstrated aerobic biodegradation of vinyl chloride (VC) was occurring in the vadose zone (i) above the on-site source zone, and (ii) above the downgradient off-site groundwater plume location. Data from both the on-site and off-site locations were consistent in showing substantially greater (an order of magnitude greater) rates of VC removal from the aerobic vadose zone compared to more recalcitrant contaminants trichloroethene (TCE) and tetrachloroethene (PCE). Soil gas VC isotope analysis showed substantial isotopic enrichment of VC (δ¹³C -5.2 to -10.9‰) compared to groundwater (δ¹³C -39.5‰) at the on-site location. Soil gas CO₂ isotope analysis at both locations showed that CO₂ was highly isotopically depleted (δ¹³C -28.8 to -33.3‰), compared to soil gas CO₂ data originating from natural sediment organic matter (δ¹³C= -14.7 to -21.3‰). The soil gas CO2 δ¹³C values were consistent with near-water table VC groundwater δ¹³C values (-36.8 to -39.5‰), suggesting CO₂ originating from aerobic biodegradation of VC. Bacteria that had functional genes (ethene monooxygenase (etnC) and epoxyalkane transferase (etnE)) involved in ethene metabolism and VC oxidation were more abundant at the source zone where oxygen co-existed with VC. The distribution of VC and oxygen vadose zone vapour plumes, together with long-term changes in soil gas CO₂ concentrations and temperature, provided information to elucidate the factors controlling aerobic biodegradation of VC in the vadose zone. Based on the overlapping VC and oxygen vadose zone vapour plumes, aerobic vapour

  7. Identification and biodegradation potential of tropical aerobic hydrocarbon-degrading microorganisms.

    PubMed

    Chaillan, Frédéric; Le Flèche, Anne; Bury, Edith; Phantavong, Y-Hui; Grimont, Patrick; Saliot, Alain; Oudot, Jean

    2004-09-01

    Screening of aerobic culturable hydrocarbon (HC)-degrading microorganisms isolated from petroleum-polluted soils and cyanobacterial mats from Indonesia resulted in the collection of 33 distinct species. Eight bacteria, 21 fungi and 4 yeasts were identified to the specific level by molecular and phenotypic techniques. Bacterial strains belonged to the genera Gordonia, Brevibacterium, Aeromicrobium, Dietzia, Burkholderia and Mycobacterium. Four species are new and not yet described. Fungi belonged to Aspergillus, Penicillium, Fusarium, Amorphoteca, Neosartorya, Paecilomyces, Talaromyces and Graphium. Yeasts were Candida, Yarrowia and Pichia. All strains were cultivated axenically in synthetic liquid media with crude oil as sole carbon and energy source. After incubation, the detailed chemical composition of the residual oil was studied by gravimetric and gas-chromatographic techniques. Thirteen parameters for assessing the biodegradation potential were defined and computed for each strain. Maximum degradation was observed on the saturated HCs (n- and isoalkanes, isoprenoids), whereas aromatic HC degradation was lower and was related to the structural composition of the molecules. A principal components analysis (PCA) permitted grouping and classifying the strains as a function of their degradative capacities. It was shown that the most active strains produced polar metabolites which accumulated in the resins and asphaltene fractions. These fractions are highly resistant to microbial metabolism. No taxonomic trend could be defined between microbial phyla in terms of HC biodegradation activity.

  8. Aerobic biodegradation of two fluorotelomer sulfonamide-based aqueous film forming foam components produces perfluoroalkyl carboxylates.

    PubMed

    D'Agostino, Lisa A; Mabury, Scott A

    2017-02-01

    The biodegradation of 2 common fluorotelomer surfactants used in aqueous film forming foams (AFFFs), 6:2 fluorotelomer sulfonamide alkylamine (FTAA) and 6:2 fluorotelomer sulfonamide alkylbetaine (FTAB), was investigated over 109 d with aerobic wastewater treatment plant (WWTP) sludge. Results show that biodegradation of 6:2 FTAA and 6:2 FTAB produces 6:2 fluorotelomer alcohol (FTOH), 6:2 fluorotelomer carboxylic acid (FTCA), 6:2 fluorotelomer unsaturated carboxylic acid (FTUCA), 5:3 FTCA, and short chain perfluoroalkyl carboxylates (PFCAs). Additional degradation products included 6:2 fluorotelomer sulfonamide (FTSAm), which was a major degradation product in the presence of either active or sterilized sludge, while 6:2 fluorotelomer sulfonate (FTSA) production was measured with sterilized sludge only. Six additional degradation products were tentatively identified by quadrupole time-of-flight mass spectrometry (qTOF-MS) and were attributed to N-dealkylation and oxidation of 6:2 FTAA. This article is protected by copyright. All rights reserved.

  9. Aerobic biodegradation kinetics and mineralization of six petrodiesel/soybean-biodiesel blends.

    PubMed

    Yassine, Mohamad H; Wu, Shuyun; Suidan, Makram T; Venosa, Albert D

    2013-05-07

    The aerobic biodegradation kinetics and mineralization of six petrodiesel/soybean-biodiesel blends (B0, B20, B40, B60, B80, and B100), where B100 is 100% biodiesel, were investigated by acclimated cultures. The fatty acid methyl esters (FAMEs) of biodiesel were found to undergo rapid abiotic transformation in all experiments. The C10-C21 n-alkanes of petrodiesel were metabolized at significantly higher microbial utilization rates in the presence of biodiesel. The rates of mineralization of the blends were also enhanced in the presence of biodiesel; yet a similar enhancement in the extent of mineralization was not observed. Abiotic fuel-blends/aqueous-phase equilibration experiments revealed that the FAMEs of biodiesel were capable of cosolubilizing the n-alkanes of petrodiesel, a mechanism that fully explains the faster utilization and mineralization kinetics of petrodiesel in the presence of biodiesel without necessarily enhancing the extent of biomineralization. The biodegradation of six targeted aromatic compounds present in petrodiesel was also influenced by the amount of biodiesel in a blend. While toluene, o-xylene, and tetralin were not degraded in the B0 and B20 treatments, all of the targeted aromatic compounds were degraded to below detection limits in the B40 and B80 treatments. Biomass acclimated to B60, however, was unable to degrade most of the aromatic compounds. These results indicate that the amount of biodiesel in a blend significantly affects the absolute and relative abundance of the dissolved and bioavailable constituents of biodiesel and petrodiesel in a way that can considerably alter the biodegrading capacity of microbial cultures.

  10. Biodegradability of Poly-3-hydroxybutyrate/Bacterial Cellulose Composites under Aerobic Conditions, Measured via Evolution of Carbon Dioxide and Spectroscopic and Diffraction Methods.

    PubMed

    Ruka, Dianne R; Sangwan, Parveen; Garvey, Christopher J; Simon, George P; Dean, Katherine M

    2015-08-18

    Poly-3-hydroxybutyrate (PHB) and bacterial cellulose (BC) are both natural polymeric materials that have the potential to replace traditional, nonrenewable polymers. In particular, the nanofibrillar form of bacterial cellulose makes it an effective reinforcement for PHB. Neat PHB, bacterial cellulose, and a composite of PHB/BC produced with 10 wt % cellulose were composted under accelerated aerobic test conditions, with biodegradability measured by the carbon dioxide evolution method, in conjunction with spectroscopic and diffraction methods to assess crystallinity changes during the biodegradation process. The PHB/BC composite biodegraded at a greater rate and extent than that of PHB alone, reaching 80% degradation after 30 days, whereas PHB did not reach this level of degradation until close to 50 days of composting. The relative crystallinity of PHB and PHB in the PHB/BC composite was found to increase in the initial weeks of degradation, with degradation occurring primarily in the amorphous region of the material and some recrystallization of the amorphous PHB. Small angle X-ray scattering indicates that the change in PHB crystallinity is accompanied by a change in morphology of semicrystalline lamellae. The increased rate of biodegradability suggests that these materials could be applicable to single-use applications and could rapidly biodegrade in compost on disposal.

  11. Biodegradability enhancement of purified terephthalic acid wastewater by coagulation-flocculation process as pretreatment.

    PubMed

    Karthik, Manikavasagam; Dafale, Nishant; Pathe, Pradyumna; Nandy, Tapas

    2008-06-15

    In this work, the coagulation-flocculation process was used as pretreatment for purified terephthalic acid (PTA) wastewater with the objective of improving its overall biodegradability. PTA production generates wastewaters with toxicants p-xylene [1,4-dimethyl-benzene (C8H10)], a major raw material used in the production process, along with some of the intermediates, viz., p-toluic acid, benzoic acid, 4-carboxybenzaldehyde, phthalic acid and terephthalic acid. These compounds affect the bio-oxidation process of wastewater treatment; hence removal of these constituents is necessary, prior to conventional aerobic treatment. This paper addresses the application of coagulation-flocculation process using chemical coagulants, viz., aluminium sulphate (alum), polyaluminium chloride (PAC), ferrous sulphate and ferric chloride in combination with anionic polyelectrolyte. Polyaluminium chloride (PAC) in conjunction with lime and polyelectrolyte removed about 63.1% chemical oxygen demand (COD) and 45.2% biochemical oxygen demand (BOD) from PTA wastewater. Coagulation-flocculation process coupled with aerobic bio-oxidation treatment of PTA wastewater achieved, COD & BOD removals of 97.4% and 99.4%, respectively. The biodegradability enhancement evaluated in terms of the BOD5/COD ratio, increased from 0.45 to 0.67 at the optimum conditions. The results obtained from these studies indicate that the coagulation-flocculation process could be a suitable pretreatment method in reducing toxicity of PTA wastewater whilst enhancing biodegradability for aerobic biological treatment scheme.

  12. [Sulfa-drug wastewater treatment with anaerobic/aerobic process].

    PubMed

    Wu, L; Zhang, H; Zhu, H; Zhang, Z; Zhuang, Y; Dai, S

    2001-09-01

    Sulfa drug wastewater was treated with anaerobic/aerobic process. The removal ratios of TOC reached about 50% in anaerobic phase and about 70% in aerobic phase respectively, while volume loading rate of TOC was about 1.2 kg/(m3.d) in anaerobic phase and about 0.6 kg/(m3.d) in aerobic phase. Removal of TOC in anaerobic phase was attributed to the reduction of sulfate.

  13. Central treatment of different emulsion wastewaters by an integrated process of physicochemically enhanced ultrafiltration and anaerobic-aerobic biofilm reactor.

    PubMed

    Zhang, Weijun; Xiao, Ping; Wang, Dongsheng

    2014-05-01

    The feasibility of an integrated process of ultrafiltration (UF) enhanced by combined chemical emulsion breaking with vibratory shear and anaerobic/aerobic biofilm reactor for central treatment of different emulsion wastewaters was investigated. Firstly, it was found that calcium chloride exhibited better performance in oil removal than other inorganic salts. Chemical demulsification pretreatment could efficiently improve oil removal and membrane filtration in emulsion wastewater treatment by VSEP. According to aerobic batch bioassay, UF permeate exhibited good biodegradability and could be further treated with biological process. Additionally, pilot test indicated that anaerobic-aerobic biofilm exhibited an excellent ability against rise in organic loading and overall chemical oxygen demand (COD) removal efficiency of biological system was more than 93% of which 82% corresponded to the anaerobic process and 11% to the aerobic degradation. The final effluent of integrated process could meet the "water quality standards for discharge to municipal sewers" in China.

  14. Aerobic biodegradation potential of endocrine disrupting chemicals in surface-water sediment at Rocky Mountains National Park, USA

    USGS Publications Warehouse

    Bradley, Paul M.; Battaglin, William A.; Iwanowicz, Luke R.; Clark, Jimmy M.; Journey, Celeste

    2016-01-01

    Endocrine disrupting chemicals (EDC) in surface water and bed sediment threaten the structure and function of aquatic ecosystems. In natural, remote, and protected surface-water environments where contaminant releases are sporadic, contaminant biodegradation is a fundamental driver of exposure concentration, timing, duration, and, thus, EDC ecological risk. Anthropogenic contaminants, including known and suspected EDC, were detected in surface water and sediment collected from 2 streams and 2 lakes in Rocky Mountains National Park (ROMO). The potential for aerobic EDC biodegradation was assessed in collected sediments using 6 14C-radiolabeled model compounds. Aerobic microbial mineralization of natural (estrone and 17β-estradiol) and synthetic (17α-ethinylestradiol) estrogen was significant at all sites. ROMO bed sediment microbial communities also effectively degraded the xenoestrogens, bisphenol-A and 4-nonylphenol. The same sediment samples exhibited little potential for aerobic biodegradation of triclocarban, however, illustrating the need to assess a wider range of contaminant compounds. The current results support recent concerns over the widespread environmental occurrence of carbanalide antibacterials, like triclocarban and triclosan, and suggest that backcountry use of products containing these compounds should be discouraged.

  15. Successful treatment of high azo dye concentration wastewater using combined anaerobic/aerobic granular activated carbon-sequencing batch biofilm reactor (GAC-SBBR): simultaneous adsorption and biodegradation processes.

    PubMed

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    The application of a granular activated carbon-sequencing batch biofilm reactor (GAC-SBBR) for treatment of wastewater containing 1,000 mg/L Acid Red 18 (AR18) was investigated in this research. The treatment system consisted of a sequencing batch reactor equipped with moving GAC as biofilm support. Each treatment cycle consisted of two successive anaerobic (14 h) and aerobic (8 h) reaction phases. Removal of more than 91% chemical oxygen demand (COD) and 97% AR18 was achieved in this study. Investigation of dye decolorization kinetics showed that the dye removal was stimulated by the adsorption capacity of the GAC at the beginning of the anaerobic phase and then progressed following a first-order reaction. Based on COD analysis results, at least 77.8% of the dye total metabolites were mineralized during the applied treatment system. High-performance liquid chromatography analysis revealed that more than 97% of 1-naphthyalamine-4-sulfonate as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase. According to the scanning electron microscopic analysis, the microbial biofilms grew in most cavities and pores of the GAC, but not on the external surfaces of the GAC.

  16. Effect of anionic and nonionic surfactants on the kinetics of the aerobic heterotrophic biodegradation of organic matter in industrial wastewater.

    PubMed

    Liwarska-Bizukojc, Ewa; Scheumann, René; Drews, Anja; Bracklow, Ute; Kraume, Matthias

    2008-02-01

    While using the contemporary mathematical models for activated sludge systems, it is necessary to describe quantitatively the kinetics of microbiological processes and to characterise substrate (wastewater components in the influent) as well as biomass (activated sludge). In this paper, the kinetic parameters of the aerobic biodegradation of organic matter in wastewater containing synthetic surfactants in an activated sludge system were determined and discussed. Also, the composition of the tested wastewater was estimated and expressed as COD fractions. Five synthetic surfactants, three anionic and two nonionic, of different chemical structure were investigated. Each of them was tested separately and dissolved in wastewater to obtain a concentration of 50 mgl(-1), which can be found in some industrial wastewater. The presence of the elevated amount of synthetic surfactants in wastewater decreased the affinity of biomass to substrate. Nevertheless, maximum specific growth rates (micromax) of heterotrophic biomass exposed to wastewater containing surfactants were high but usually lower than micromax estimated for wastewater without surfactant. Surfactants, which contain a benzene ring, were the most likely to deteriorate wastewater treatment processes in the activated sludge systems.

  17. Biodegradation of three- and four-ring polycyclic aromatic hydrocarbons under aerobic and denitrifying conditions

    SciTech Connect

    McNally, D.L.; Mihelcic, J.R.; Lueking, D.R.

    1998-09-01

    PAHs are thought to be particularly persistent in environments where anaerobic conditions exist. This study presents evidence for the biodegradation of three- and four-ringed PAHs (anthracene, phenanthrene, and pyrene) under strict anaerobic, denitrifying conditions. Three pseudomonad strains, isolated from contrasting environments, were used in this study. All three strains were known PAH degraders and denitrifiers. Degradation proceeded to nondetectable levels in 12--80 h for anthracene, 12--44 h for phenanthrene, and 24--72 h for pyrene. The rates of anaerobic degradation were typically slower than under aerobic conditions in almost all cases, except for strain SAG-R which had similar removal rates for all three and four-ring PAHs. Denitrification activity was verified by monitoring nitrate utilization and nitrous oxide production. Although none of the pseudomonads were adapted to the denitrifying conditions, only the pseudomonad isolated from a noncontaminated site consistently exhibited an adaptation period which approximated 12 h. This study supports growing evidence that the degradation of aromatic hydrocarbons coupled to denitrification may be an important factor affecting the fate of these compounds in natural and engineered systems.

  18. Modelling aerobic biodegradation in vertical flow sand filters: impact of operational considerations on oxygen transfer and bacterial activity.

    PubMed

    Petitjean, A; Forquet, N; Wanko, A; Laurent, J; Molle, P; Mosé, R; Sadowski, A

    2012-05-01

    Oxygen renewal, as a prominent phenomenon for aerobic bacterial activity, deeply impacts Vertical Flow Constructed Wetland (VFCW) treatment efficiency. We introduce a multiphase model able to simulate multi-component transfer in VFCWs. It is based on a two-phase flow module, and a transport module. The flow module can quantify both water and air velocities throughout the filter during operation. The reactive transport module follows dissolved and gaseous oxygen concentrations, and the transport of solutes such as ammonium and readily biodegradable COD (Chemical Oxygen Demand). The consumption of components is governed by Monod-type kinetics. Heterotrophic and autotrophic bacteria, which are responsible for COD and ammonium degradation respectively, are part of the model components. The kinetics are based on the Constructed Wetlands Model 1. The results from the simulation tool were compared with existing experimental data, and two kinds of operation with VFCWs were investigated. The authors show strong interplay between oxygen renewal and bacterial consumption in case of sequential batch feeding with transient flooding of surface. Oxygen renewal is essentially convection mediated in such operation, while convection is not significant in non-flooding operation. Simulated bacterial patterns are impacted by the operation, both quantitatively and spatially. From a modelling point of view, the authors highlight some limitations of the biological model: the description of bacterial lysis processes needs to be enhanced, as well as ammonium adsorption to organic matter.

  19. Study on the aerobic biodegradability and degradation kinetics of 3-NP; 2,4-DNP and 2,6-DNP.

    PubMed

    She, Zonglian; Xie, Tian; Zhu, Yingjie; Li, Leilei; Tang, Gaifeng; Huang, Jian

    2012-11-30

    Four biodegradability tests (BOD(5)/COD ratio, production of carbon dioxide, relative oxygen uptake rate and relative enzymatic activity) were used to determine the aerobic biodegradability of 3-nitrophenol (3-NP), 2,4-dinitrophenol (2,4-DNP) and 2,6-dinitrophenol (2,6-DNP). Furthermore, biodegradation kinetics of the compounds was investigated in sequencing batch reactors both in the presence of glucose (co-substrate) and with nitrophenol as the sole carbon source. Among the three tested compounds, 3-NP showed the best biodegradability while 2,6-DNP was the most difficult to be biodegraded. The Haldane equation was applied to the kinetic test data of the nitrophenols. The kinetic constants are as follows: the maximum specific degradation rate (K(max)), the saturation constants (K(S)) and the inhibition constants (K(I)) were in the range of 0.005-2.98 mg(mgSS d)(-1), 1.5-51.9 mg L(-1) and 1.8-95.8 mg L(-1), respectively. The presence of glucose enhanced the degradation of the nitrophenols at low glucose concentrations. The degradation of 3-NP was found to be accelerated with the increasing of glucose concentrations from 0 to 660 mg L(-1). At high (1320-2000 mg L(-1)) glucose concentrations, the degradation rate of 3-NP was reduced and the K(max) of 3-NP was even lower than the value obtained in the absence of glucose, suggesting that high concentrations of co-substrate could inhibit 3-NP biodegradation. At 2,4-DNP concentration of 30 mg L(-1), the K(max) of 2,4-DNP with glucose as co-substrate was about 30 times the value with 2,4-DNP as sole substrate. 2,6-DNP preformed high toxicity in the case of sole carbon source degradation and the kinetic data was hardly obtained.

  20. Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation.

    PubMed

    Wei, Liangliang; Li, Siliang; Noguera, Daniel R; Qin, Kena; Jiang, Junqiu; Zhao, Qingliang; Kong, Xiangjuan; Cui, Fuyi

    2015-06-01

    Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly.

  1. Aerobic biodegradation of a mixture of monosubstituted phenols in a sequencing batch reactor.

    PubMed

    Fernández, Isaac; Suárez-Ojeda, María Eugenia; Pérez, Julio; Carrera, Julián

    2013-09-15

    A sequencing batch reactor (SBR) was inoculated with p-nitrophenol-degrading activated sludge to biodegrade a mixture of monosubstituted phenols: p-nitrophenol (PNP), PNP and o-cresol; and PNP, o-cresol and o-chlorophenol. Settling times were progressively decreased to promote biomass granulation. PNP was completely biodegraded. The PNP and o-cresol mixture was also biodegraded although some transitory accumulation of intermediates occurred (mainly hydroquinone and catechol). o-Chlorophenol was not biodegraded and resulted in inhibition of o-cresol and PNP biodegradation and complete failure of the SBR within a few days. The biomass had very good settling properties when a settling time of 1 min was applied: sludge volume index (SVI₅) below 50 mL g(-1), SVI₅/SVI₃₀ ratio of 1 and average particle size of 200 μm.

  2. Aerobic Digestion. Biological Treatment Process Control. Instructor's Guide.

    ERIC Educational Resources Information Center

    Klopping, Paul H.

    This unit on aerobic sludge digestion covers the theory of the process, system components, factors that affect the process performance, standard operational concerns, indicators of steady-state operations, and operational problems. The instructor's guide includes: (1) an overview of the unit; (2) lesson plan; (3) lecture outline (keyed to a set of…

  3. Aerobic and anaerobic cecal bacterial flora of commercially processed broilers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Differences in the bacterial flora of aerobic and anaerobic cultures of broiler ceca collected from a commercial poultry processing facility were determined. Bacterial isolates from cecal cultures were selected based on the ability of the bacteria to grow in media supplemented with lactate and succ...

  4. Numerical modeling analysis of VOC removal processes in different aerobic vertical flow systems for groundwater remediation.

    PubMed

    De Biase, Cecilia; Carminati, Andrea; Oswald, Sascha E; Thullner, Martin

    2013-11-01

    Vertical flow systems filled with porous medium have been shown to efficiently remove volatile organic contaminants (VOCs) from contaminated groundwater. To apply this semi-natural remediation strategy it is however necessary to distinguish between removal due to biodegradation and due to volatile losses to the atmosphere. Especially for (potentially) toxic VOCs, the latter needs to be minimized to limit atmospheric emissions. In this study, numerical simulation was used to investigate quantitatively the removal of volatile organic compounds in two pilot-scale water treatment systems: an unplanted vertical flow filter and a planted one, which could also be called a vertical flow constructed wetland, both used for the treatment of contaminated groundwater. These systems were intermittently loaded with contaminated water containing benzene and MTBE as main VOCs. The highly dynamic but permanently unsaturated conditions in the porous medium facilitated aerobic biodegradation but could lead to volatile emissions of the contaminants. Experimental data from porous material analyses, flow rate measurements, solute tracer and gas tracer test, as well as contaminant concentration measurements at the boundaries of the systems were used to constrain a numerical reactive transport modeling approach. Numerical simulations considered unsaturated water flow, transport of species in the aqueous and the gas phase as well as aerobic degradation processes, which made it possible to quantify the rates of biodegradation and volatile emissions and calculating their contribution to total contaminant removal. A range of degradation rates was determined using experimental results of both systems under two operation modes and validated by field data obtained at different operation modes applied to the filters. For both filters, simulations and experimental data point to high biodegradation rates, if the flow filters have had time to build up their removal capacity. For this case volatile

  5. Influence of adhesion on aerobic biodegradation and bioremediation of liquid hydrocarbons.

    PubMed

    Abbasnezhad, Hassan; Gray, Murray; Foght, Julia M

    2011-11-01

    Biodegradation of poorly water-soluble liquid hydrocarbons is often limited by low availability of the substrate to microbes. Adhesion of microorganisms to an oil-water interface can enhance this availability, whereas detaching cells from the interface can reduce the rate of biodegradation. The capability of microbes to adhere to the interface is not limited to hydrocarbon degraders, nor is it the only mechanism to enable rapid uptake of hydrocarbons, but it represents a common strategy. This review of the literature indicates that microbial adhesion can benefit growth on and biodegradation of very poorly water-soluble hydrocarbons such as n-alkanes and large polycyclic aromatic hydrocarbons dissolved in a non-aqueous phase. Adhesion is particularly important when the hydrocarbons are not emulsified, giving limited interfacial area between the two liquid phases. When mixed communities are involved in biodegradation, the ability of cells to adhere to the interface can enable selective growth and enhance bioremediation with time. The critical challenge in understanding the relationship between growth rate and biodegradation rate for adherent bacteria is to accurately measure and observe the population that resides at the interface of the hydrocarbon phase.

  6. TBA biodegradation in surface-water sediments under aerobic and anaerobic conditions

    USGS Publications Warehouse

    Bradley, P.M.; Landmeyer, J.E.; Chapelle, F.H.

    2002-01-01

    The potential for [U-14C] TBA biodegradation was examined in laboratory microcosms under a range of terminal electron accepting conditions. TBA mineralization to CO2 was substantial in surface-water sediments under oxic, denitrifying, or Mn(IV)-reducing conditions and statistically significant but low under SO4-reducing conditions. Thus, anaerobic TBA biodegradation may be a significant natural attenuation mechanism for TBA in the environment, and stimulation of in situ TBA bioremediation by addition of suitable terminal electron acceptors may be feasible. No degradation of [U-14C] TBA was observed under methanogenic or Fe(III)-reducing conditions.

  7. Biodegradation of 17β-estradiol by bacteria isolated from deep sea sediments in aerobic and anaerobic media.

    PubMed

    Fernández, Lucía; Louvado, António; Esteves, Valdemar I; Gomes, Newton C M; Almeida, Adelaide; Cunha, Ângela

    2017-02-05

    Endocrine disrupting compounds (EDCs) are considered as high research priority being a source of potential adverse ecological health effects in environmental waters. 17β-Estradiol (E2), a recalcitrant natural estrogen, is typically encountered in wastewater treatment plants (WWTPs) at levels ranging 10-30ngL(-1) in the influent flow and 1-3ngL(-1) in the effluent flow. The exposure to even extremely low concentrations of E2 may interfere with the normal function of the endocrine system of organisms. In this study, five bacteria isolated from enrichment cultures of sediments of mud volcanoes of the Gulf of Cadiz (Moroccan-Iberian margin) were identified as aerobic E2 biodegraders, which produce low amounts of biotransformed estrone (E1). Analysis of 16S rDNA gene sequences identified three of them as Virgibacillus halotolerans, Bacillus flexus and Bacillus licheniformis. Among the set of strains, Bacillus licheniformis showed also ability to biodegrade E2 under anaerobic conditions.

  8. Monitoring of the aerobe biodegradation of chlorinated organic solvents by stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Horváth, Anikó; Futó, István; Palcsu, László

    2014-05-01

    Our chemical-biological basic research aims to eliminate chlorinated environmental contaminants from aquifers around industrial areas in the frame of research program supported by the European Social Fund (TÁMOP-4.2.2.A-11/1/KONV-2012-0043). The most careful and simplest way includes the in situ biodegradation with the help of cultured and compound specific strains. Numerous members of Pseudomonas bacteria are famous about function of bioremediation. They can metabolism the environmental hazardous chemicals like gas oils, dyes, and organic solvents. Our research based on the Pseudomonas putida F1 strain, because its ability to degrade halogenated hydrocarbons such as trichloroethylene. Several methods were investigated to estimate the rate of biodegradation, such as the measurement of the concentration of the pollutant along the contamination pathway, the microcosm's studies or the compound specific stable isotope analysis. In this area in the Transcarpathian basin we are pioneers in the stable isotope monitoring of biodegradation. The main goal is to find stable isotope fractionation factors by stable isotope analysis, which can help us to estimate the rate and effectiveness of the biodegradation. The subsequent research period includes the investigation of the method, testing its feasibility and adaptation in the environment. Last but not least, the research gives an opportunity to identify the producer of the contaminant based on the stable isotope composition of the contaminant.

  9. Biodegradation of Cry1Ab protein from Bt transgenic rice in aerobic and flooded paddy soils.

    PubMed

    Wang, Haiyan; Ye, Qingfu; Gan, Jay; Wu, Licheng

    2007-03-07

    Degradation of Cry1Ab protein from Bt transgenic rice was examined under both aerobic and flooded conditions in five paddy soils and in aqueous solutions. The hydrolysis rate of Cry1Ab protein in aqueous solutions was correlated inversely with the solution pH in the range of 4.0 to 8.0, and positively with the initial concentration of Cry1Ab protein. Rapid degradation of Cry1Ab protein occurred in paddy soils under aerobic conditions, with half-lives ranging from 19.6 to 41.3 d. The degradation was mostly biotic and not related to any specific soil property. Degradation of the Cry1Ab protein was significantly prolonged under flooded conditions compared with aerobic conditions, with half-lives extended to 45.9 to 141 d. These results suggest that the toxin protein, when introduced into a paddy field upon harvest, will probably undergo rapid removal after the field is drained and exposed to aerobic conditions.

  10. Biodegradability and process characterization of nonwovens formed from cotton and cellulose acetate fibers

    NASA Astrophysics Data System (ADS)

    Suh, Hageun

    A possible candidate as an environmentally friendly nonwoven fabric is one which can be formed from the thermal calendering of a cotton/cellulose acetate blend. The results presented have focused on biodegradable properties of the fibers, physical properties of the fabric, and process optimization of the thermal calendering. Biodegradation of cellulose has been intensively studied, and cellulose is believed to be readily biodegraded by many microorganisms due to the activity of cellulase enzymes. However, the biodegradability of cellulose acetate (CA) is less than certain. To determine a semi-quantitative measure of the biodegradation of CA fibers, the AATCC test method 30-1988 was selected. After a 12-week soil burial test, evidence of microbial attack on CA fabric was obtained on the basis of 27% strength loss. As a more reliable method, the ASTM test method D5209-91, an aerobic sludge test, was adopted, in which the amount of COsb2 evolved from the decomposition of CA, cotton and fiber blends was measured. The biodegradability of CA fibers was confirmed by showing COsb2 evolution, and the synergistic effects of multi-enzyme systems between cellulase and esterase were suggested based on the increased biodegradation rates in fiber blends. Opening, blending, carding, and thermal calendering processes were used in the fabrication of the nonwovens. Pretreatment with solvent vapors was introduced for modifying the softening temperatures of the cellulose acetate and for lowering the calendering temperatures required otherwise. The success of the solvent-assisted thermal calendering is demonstrated in enhanced tensile strengths of the nonwoven obtained with lower calendering temperatures. For process optimization, the experiment was designed for a 3-way factorial design with the following factors: bonding temperature, blend ratio and solvent treatment time. The effects of the factors on 18 physical properties were determined by analysis of variance, least

  11. Biodegradable and radically polymerized elastomers with enhanced processing capabilities.

    PubMed

    Ifkovits, Jamie L; Padera, Robert F; Burdick, Jason A

    2008-09-01

    The development of biodegradable materials with elastomeric properties is beneficial for a variety of applications, including for use in the engineering of soft tissues. Although others have developed biodegradable elastomers, they are restricted by their processing at high temperatures and under vacuum, which limits their fabrication into complex scaffolds. To overcome this, we have modified precursors to a tough biodegradable elastomer, poly(glycerol sebacate) (PGS) with acrylates to impart control over the crosslinking process and allow for more processing options. The acrylated-PGS (Acr-PGS) macromers are capable of crosslinking through free radical initiation mechanisms (e.g., redox and photo-initiated polymerizations). Alterations in the molecular weight and % acrylation of the Acr-PGS led to changes in formed network mechanical properties. In general, Young's modulus increased with % acrylation and the % strain at break increased with molecular weight when the % acrylation was held constant. Based on the mechanical properties, one macromer was further investigated for in vitro and in vivo degradation and biocompatibility. A mild to moderate inflammatory response typical of implantable biodegradable polymers was observed, even when formed as an injectable system with redox initiation. Moreover, fibrous scaffolds of Acr-PGS and a carrier polymer, poly(ethylene oxide), were prepared via an electrospinning and photopolymerization technique and the fiber morphology was dependent on the ratio of these components. This system provides biodegradable polymers with tunable properties and enhanced processing capabilities towards the advancement of approaches in engineering soft tissues.

  12. Effect of the process conditions of aerobic bioconversion on the characteristics of biologically processed brown coals

    SciTech Connect

    I.P. Ivanov

    2007-04-15

    The effect of the laboratory and pilot process conditions of the aerobic bioconversion of brown coals on the elemental composition and technical characteristics of the organic matter of the resulting biologically processed coals is reported.

  13. Study on biodegradation process of lignin by FTIR and DSC.

    PubMed

    Liu, Yang; Hu, Tianjue; Wu, Zhengping; Zeng, Guangming; Huang, Danlian; Shen, Ying; He, Xiaoxiao; Lai, Mingyong; He, Yibin

    2014-12-01

    The biodegradation process of lignin by Penicillium simplicissimum was studied to reveal the lignin biodegradation mechanisms. The biodegradation products of lignin were detected using Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometer, different scanning calorimeter (DSC), and stereoscopic microscope. The analysis of FTIR spectrum showed the cleavage of various ether linkages (1,365 and 1,110 cm(-1)), oxidation, and demethylation (2,847 cm(-1)) by comparing the different peak values in the corresponding curve of each sample. Moreover, the differences (Tm and ΔHm values) between the DSC curves indirectly verified the FTIR analysis of biodegradation process. In addition, the effects of adding hydrogen peroxide (H2O2) to lignin biodegradation process were analyzed, which indicated that H2O2 could accelerate the secretion of the MnP and LiP and improve the enzymes activity. What is more, lignin peroxidase and manganese peroxidase catalyzed the lignin degradation effectively only when H2O2 was presented.

  14. Effect of butylated hydroxytoluene (BHT) on the aerobic biodegradation of a model vegetable oil in aquatic media.

    PubMed

    Salam, Darine A; Suidan, Makram T; Venosa, Albert D

    2012-06-19

    Antioxidants added to vegetable oils to prevent lipid oxidation significantly affect their biodegradation in impacted aquatic environments. In this study, the effect of butylated-hydroxytoluene (BHT) on the biodegradation of glyceryl trilinoleate, a model vegetable oil highly susceptible to autoxidation, was determined. Biodegradation experiments were conducted in respirometric microcosms at an oil loading of 333 gal acre(-1) (0.31 L m(-2)) and BHT concentrations ranging from 0 to 800 mg kg(-1) (0, 50, 100, 200, 400, and 800 mg kg(-1)). Competition between polymerization and biodegradation of the oil was observed at all BHT concentrations and was significant in the microcosms not supplemented with the antioxidant. In all microcosms, intractable rigid polymers unavailable for bacterial degradation were formed. Infrared analysis evidenced the advanced stages of the oil autoxidation. After 19 weeks of incubation, only about 41% of the oil was mineralized in the microcosms with no BHT. However, mineralization exceeded 67% in the microcosms with added antioxidant and did not significantly increase with increasing BHT concentrations. Biodegradation rate constants were calculated by nonlinear regression and were not significantly different in the microcosms with added BHT (k = 0.001 h(-1)). Higher k values were measured in the microcosms lacking the antioxidant (k = 0.0023 h(-1)), most likely due to the increased oxygen consumption associated with the autoxidation process in this case. No toxicity was detected in all biotic microcosms at the end of the incubation period, while high toxicity (EC(50) = 4.78%) was measured in the abiotic blanks with no antioxidant and was attributed to the accumulation of autoxidation products.

  15. Enhancing aerobic biodegradation of 1,2-dibromoethane in groundwater using ethane or propane and inorganic nutrients

    NASA Astrophysics Data System (ADS)

    Hatzinger, Paul B.; Streger, Sheryl H.; Begley, James F.

    2015-01-01

    1,2-Dibromoethane (ethylene dibromide; EDB) is a probable human carcinogen that was previously used as both a soil fumigant and a scavenger in leaded gasoline. EDB has been observed to persist in soils and groundwater, particularly under oxic conditions. The objective of this study was to evaluate options to enhance the aerobic degradation of EDB in groundwater, with a particular focus on possible in situ remediation strategies. Propane gas and ethane gas were observed to significantly stimulate the biodegradation of EDB in microcosms constructed with aquifer solids and groundwater from the FS-12 EDB plume at Joint Base Cape Cod (Cape Cod, MA), but only after inorganic nutrients were added. Ethene gas was also effective, but rates were appreciably slower than for ethane and propane. EDB was reduced to < 0.02 μg/L, the Massachusetts state Maximum Contaminant Level (MCL), in microcosms that received ethane gas and inorganic nutrients. An enrichment culture (BE-3R) that grew on ethane or propane gas but not EDB was obtained from the site materials. The degradation of EDB by this culture was inhibited by acetylene gas, suggesting that degradation is catalyzed by a monooxygenase enzyme. The BE-3R culture was also observed to biodegrade 1,2-dichloroethane (DCA), a compound commonly used in conjunction with EDB as a lead scavenger in gasoline. The data suggest that addition of ethane or propane gas with inorganic nutrients may be a viable option to enhance degradation of EDB in groundwater aquifers to below current state or federal MCL values.

  16. Aerobic biodegradation of a sulfonated phenylazonaphthol dye by a bacterial community immobilized in a multistage packed-bed BAC reactor.

    PubMed

    Ruiz-Arias, Alfredo; Juárez-Ramírez, Cleotilde; de los Cobos-Vasconcelos, Daniel; Ruiz-Ordaz, Nora; Salmerón-Alcocer, Angélica; Ahuatzi-Chacón, Deifilia; Galíndez-Mayer, Juvencio

    2010-11-01

    A microbial community able to aerobically degrade the azo dye Acid Orange 7 was selected from riparian or lacustrine sediments collected at sites receiving textile wastewaters. Three bacterial strains, pertaining to the genera Pseudomonas, Arthrobacter, and Rhizobium, constitute the selected community. The biodegradation of AO7 was carried out in batch-suspended cell culture and in a continuously operated multistage packed-bed BAC reactor. The rapid decolorization observed in batch culture, joined to a delay of about 24 h in COD removal and cell growth, suggests that enzymes involved in biodegradation of the aromatic amines generated after AO7 azo-bond cleavage (1-amino-2-naphthol [1-A2N] and 4-aminobenzenesulfonic acid [4-ABS]), are inducible in this microbial consortium. After this presumptive induction period, the accumulated byproducts, measured through COD, were partially metabolized and transformed in cell mass. At all azo dye loading rates used, complete removal of AO7 and 1-A2N was obtained in the multistage packed-bed BAC reactor (PBR).; however, the overall COD (eta ( COD )) and 4-ABS (eta ( ABS )) removal efficiencies obtained in steady state continuous culture were about 90%. Considering the toxicity of 1-A2N, its complete removal has particular relevance. In the first stages of the packed-bed BAC reactor (Fig. 4a-c), major removal was observed. In the last stage, only a slight removal of COD and 4-ABS was obtained. Comparing to several reported studies, the continuously operated multistage packed-bed BAC reactor showed similar or superior results. In addition, the operation of large-packed-bed BAC reactors could be improved by using several shallow BAC bed stages, because the pressure drop caused by bed compaction of a support material constituted by small and fragile particles can be reduced.

  17. Aerobic biodegradation of 2,2'-dithiodibenzoic acid produced from dibenzothiophene metabolites

    SciTech Connect

    Young, R.F.; Cheng, S.M.; Fedorak, P.M.

    2006-01-15

    Dibenzothiophene is a sulfur heterocycle found in crude oils and coal. The biodegradation of dibenzothiophene through the Kodama pathway by Pseudomonas sp. strain BT1d leads to the formation of three disulfides: 2-oxo-2-(2-thiophenyl)ethanoic acid disulfide, 2-oxo-2-(2-thiophenyl)ethanoic acid-2-benzoic acid disulfide, and 2,2'-dithiodibenzoic acid. When provided as the carbon and sulfur source in liquid medium, 2,2'-dithiodibenzoic acid was degraded by soil enrichment cultures. Two bacterial isolates, designated strains RM1 and RM6, degraded 2,2'-dithiodibenzoic acid when combined in the medium. Isolate RM6 was found to have an absolute requirement for vitamin B{sub 12}, and it degraded 2,2'-dithiodibenzoic acid in pure culture when the medium was supplemented with this vitamin. Isolate RM6 also degraded 2,2'-dithiodibenzoic acid in medium containing sterilized supernatants from cultures of isolate RM1 grown on glucose or benzoate. Isolate RM6 was identified as a member of the genus Variovorax using the Biolog system and 16S rRNA gene analysis. Although the mechanism of disulfide metabolism could not be determined, benzoic acid was detected as a transient metabolite of 2,2'-dithiodibenzoic acid biodegradation by Variovorax sp. strain RM6. In pure culture, this isolate mineralized 2,2'-dithiodibenzoic acid, releasing 59% of the carbon as carbon dioxide and 88% of the sulfur as sulfate.

  18. Effect of temperature on the efficiency of the thermo- and mesophilic aerobic batch biodegradation of high-strength distillery wastewater (potato stillage).

    PubMed

    Krzywonos, Małgorzata; Cibis, Edmund; Miśkiewicz, Tadeusz; Kent, Chris A

    2008-11-01

    The objective of the study was to assess the effect of temperature on the extent of aerobic batch biodegradation of potato stillage with a mixed culture of bacteria of the genus Bacillus. The experiments were performed in a 5-l stirred-tank reactor at 20, 30, 35, 40, 45, 50, 55, 60, 63 and 65 degrees C with the pH of 7. Only at 65 degrees C, no reduction in chemical oxygen demand (COD) was found to occur. Over the temperature range of 20-63 degrees C, the removal efficiency was very high (with an extent of COD reduction following solids separation that varied between 77.57% and 89.14% after 125 h). The process ran at the fastest rate when the temperature ranged from 30 to 45 degrees C; after 43 h at the latest, COD removal amounted to 90% of the final removal efficiency value obtained for the process. At 20, 55, 60 and 63 degrees C, a 90% removal was attained after 80 h. Two criteria were proposed for the identification of the point in time when the process is to terminate. One of these consists in maximising the product of the extent of COD reduction and the extent of N-NH4 content reduction. The other criterion is a simplified one and involves the search for the minimal value of N-NH4 concentration.

  19. Non-biodegradable landfill leachate treatment by combined process of agitation, coagulation, SBR and filtration.

    PubMed

    Abood, Alkhafaji R; Bao, Jianguo; Du, Jiangkun; Zheng, Dan; Luo, Ye

    2014-02-01

    This study describes the complete treatment of non-biodegradable landfill leachate by combined treatment processes. The processes consist of agitation as a novel stripping method used to overcome the ammonia toxicity regarding aerobic microorganisms. The NH3-N removal ratio was 93.9% obtained at pH 11.5 and a gradient velocity (G) 150 s(-1) within a five-hour agitation time. By poly ferric sulphate (PFS) coagulation followed the agitation process; chemical oxygen demand (COD) and biological oxygen demand (BOD5) were removed at 70.6% and 49.4%, respectively at an optimum dose of 1200 mg L(-1) at pH 5.0. The biodegradable ratio BOD5/COD was improved from 0.18 to 0.31 during pretreatment step by agitation and PFS coagulation. Thereafter, the effluent was diluted with sewage at a different ratio before it was subjected to sequencing batch reactor (SBR) treatment. Up to 93.3% BOD5, 95.5% COD and 98.1% NH3-N removal were achieved by SBR operated under anoxic-aerobic-anoxic conditions. The filtration process was carried out using sand and carbon as a dual filter media as polishing process. The final effluent concentration of COD, BOD5, suspended solid (SS), NH3-N and total organic carbon (TOC) were 72.4 mg L(-1), 22.8 mg L(-1), 24.2 mg L(-1), 18.4 mg L(-1) and 50.8 mg L(-1) respectively, which met the discharge standard. The results indicated that a combined process of agitation-coagulation-SBR and filtration effectively eliminated pollutant loading from landfill leachate.

  20. Carbon and Hydrogen Isotopic Fractionation during Anaerobic Biodegradation of Benzene

    PubMed Central

    Mancini, Silvia A.; Ulrich, Ania C.; Lacrampe-Couloume, Georges; Sleep, Brent; Edwards, Elizabeth A.; Sherwood Lollar, Barbara

    2003-01-01

    Compound-specific isotope analysis has the potential to distinguish physical from biological attenuation processes in the subsurface. In this study, carbon and hydrogen isotopic fractionation effects during biodegradation of benzene under anaerobic conditions with different terminal-electron-accepting processes are reported for the first time. Different enrichment factors (ɛ) for carbon (range of −1.9 to −3.6‰) and hydrogen (range of −29 to −79‰) fractionation were observed during biodegradation of benzene under nitrate-reducing, sulfate-reducing, and methanogenic conditions. These differences are not related to differences in initial biomass or in rates of biodegradation. Carbon isotopic enrichment factors for anaerobic benzene biodegradation in this study are comparable to those previously published for aerobic benzene biodegradation. In contrast, hydrogen enrichment factors determined for anaerobic benzene biodegradation are significantly larger than those previously published for benzene biodegradation under aerobic conditions. A fundamental difference in the previously proposed initial step of aerobic versus proposed anaerobic biodegradation pathways may account for these differences in hydrogen isotopic fractionation. Potentially, C-H bond breakage in the initial step of the anaerobic benzene biodegradation pathway may account for the large fractionation observed compared to that in aerobic benzene biodegradation. Despite some differences in reported enrichment factors between cultures with different terminal-electron-accepting processes, carbon and hydrogen isotope analysis has the potential to provide direct evidence of anaerobic biodegradation of benzene in the field. PMID:12513995

  1. Improvement of Landfill Leachate Biodegradability with Ultrasonic Process

    PubMed Central

    Mahvi, Amir Hossein; Roodbari, Ali Akbar; Nabizadeh Nodehi, Ramin; Nasseri, Simin; Dehghani, Mohammad Hadil; Alimohammadi, Mahmood

    2012-01-01

    Landfills leachates are known to contain recalcitrant and/or non-biodegradable organic substances and biological processes are not efficient in these cases. A promising alternative to complete oxidation of biorecalcitrant leachate is the use of ultrasonic process as pre-treatment to convert initially biorecalcitrant compounds to more readily biodegradable intermediates. The objectives of this study are to investigate the effect of ultrasonic process on biodegradability improvement. After the optimization by factorial design, the ultrasonic were applied in the treatment of raw leachates using a batch wise mode. For this, different scenarios were tested with regard to power intensities of 70 and 110 W, frequencies of 30, 45 and 60 KHz, reaction times of 30, 60, 90 and 120 minutes and pH of 3, 7 and 10. For determining the effects of catalysts on sonication efficiencies, 5 mg/l of TiO2 and ZnO have been also used. Results showed that when applied as relatively brief pre-treatment systems, the sonocatalysis processes induce several modifications of the matrix, which results in significant enhancement of its biodegradability. For this reason, the integrated chemical–biological systems proposed here represent a suitable solution for the treatment of landfill leachate samples. PMID:22829863

  2. Biodegradation Rates Assessment For An In Situ Bioremediation Process

    NASA Astrophysics Data System (ADS)

    Troquet, J.; Poutier, F.

    Bioremediation methods seem a promising way of dealing with soil and subsoil con- tamination by organic substances. The biodegradation process is supported by micro- organisms which use the organic carbon from the pollutants as energy source and cells building blocks. However, bioremediation is not yet universally understood and its success is still an intensively debated issue because all soils and groundwater are not able to sustain biological growth and, then, cannot be successfully bioremediated. The outcome of each degradation process depends on several factors, which, such as oxygen transfer and pollutant bio-availability, can be controlled and are therefore key variables of such bioremediation processes. Then, it is essential to carry out a fea- sibility study based on pilot-testing before starting a remediation project in order to determine the best formulation of nutrients and bacteria to use for the specific condi- tions encountered. The scope of this work is to study the main parameters of the process and its physi- cal limiting steps in order to determine the biodegradation rates in a specific case of contamination. Several ground samples from an actual petroleum hydrocarbon con- taminated site have been laboratory tested. Five fixed bed column reactors, enabling the study of the influence of the different op- erating variables on the biodegradation kinetics, are used. The stoichiometric equation for bacteria growth and pollutant degradation has been established, allowing the de- termination of mass balances. Biodegradation monitoring is achieved by continuously measuring the emissions of carbon dioxide production and intermittently by analysing residual hydrocarbons. Results lead to the knowledge of biodegradation rates which allow to determine the treatment duration and cost.

  3. Factors Affecting the Success of Enhanced Aerobic Biodegradation of MTBE and BTEX

    NASA Astrophysics Data System (ADS)

    Landmeyer, J. E.; Bradley, P. M.

    2002-12-01

    At a gasoline-release site in South Carolina, a proprietary form of MgO2 injected into the subsurface in a former underground storage tank (UST) area to increase dissolved oxygen (DO) levels did not elevate low (0 mg/L) DO levels nor decrease concentrations of benzene, toluene, or methyl tert-butyl ether (MTBE). In contrast, MgO2 injected less than 200 meters downgradient rapidly increased DO, and benzene, toluene, and MTBE concentrations decreased up to 87%. These different results following oxygen addition to an anoxic fuel-contaminated aquifer can be related to differences in ambient hydrologic conditions between the two areas that supported different microbial communities with respect to contaminant degradation prior to oxygen-based remediation. For example, although fuel-contaminated ground water downgradient of the source area was anoxic, infiltration of DO-rich recharge occurred through overlying permeable sediments for some time before oxygen injection. In contrast, this natural input of DO does not occur in the paved, former UST area. Moreover, the absence of recharge in the source area permitted the accumulation of reduced mineral- and soluble-inorganic species, a significant oxygen sink that competed with contaminant biodegradation demand for the injected oxygen. This talk will describe the relation that exists between hydrologic and microbiologic conditions in contaminated shallow ground-water systems exhibited at this site, and why certain parameters should be measured as part of any oxygen-based remedial strategies.

  4. Aerobic Biodegradation of N-Nitrosodimethylamine by the Propanotroph Rhodococcus ruber ENV425▿

    PubMed Central

    Fournier, Diane; Hawari, Jalal; Halasz, Annamaria; Streger, Sheryl H.; McClay, Kevin R.; Masuda, Hisako; Hatzinger, Paul B.

    2009-01-01

    The propanotroph Rhodococcus ruber ENV425 was observed to rapidly biodegrade N-nitrosodimethylamine (NDMA) after growth on propane, tryptic soy broth, or glucose. The key degradation intermediates were methylamine, nitric oxide, nitrite, nitrate, and formate. Small quantities of formaldehyde and dimethylamine were also detected. A denitrosation reaction, initiated by hydrogen atom abstraction from one of the two methyl groups, is hypothesized to result in the formation of n-methylformaldimine and nitric oxide, the former of which decomposes in water to methylamine and formaldehyde and the latter of which is then oxidized further to nitrite and then nitrate. Although the strain mineralized more than 60% of the carbon in [14C]NDMA to 14CO2, growth of strain ENV425 on NDMA as a sole carbon and energy source could not be confirmed. The bacterium was capable of utilizing NDMA, as well as the degradation intermediates methylamine and nitrate, as sources of nitrogen during growth on propane. In addition, ENV425 reduced environmentally relevant microgram/liter concentrations of NDMA to <2 ng/liter in batch cultures, suggesting that the bacterium may have applications for groundwater remediation. PMID:19542346

  5. Biodegradation of bisphenol A and other bisphenols by a gram-negative aerobic bacterium

    SciTech Connect

    Lobos, J.H.; Leib, T.K. ); Tahmun Su )

    1992-06-01

    A novel bacterium designated strain MV1 was isolated from a sludge enrichmet takes from the wastewater treatment plant at a plastics manufacturing facility and shown to degrade 2,2-bis(4-hydroxyphenyl)propane (4,4[prime]-isopropylidenediphenol or bisphenol A). Strain MV1 is a gram-negative, aerobic bacillus that grows on bisphenol A as a sole source of carbon and energy. Total carbon analysis for bisphenol A degradation demonstrated that 60% of the carbon was mineralized to CO[sub 2], 20% was associated with the bacterial cells, and 20% was converted to soluble organic compounds. Metabolic intermediates detected in the culture medium during growth on bisphenol A were identified as 4-hydroxybenzoic acid, 4-hydroxyacetophenone, 2,2-bis(4-hydroxyphenyl)-1-propanol, and 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. Most of the bisphenol A degraded by strain MV1 is cleaved in some way to form 4-hydroxybenzoic acid and 4-hydroxyacetophenone, which are subsequently mineralized or assimilated into cell carbon. In addition, about 20% of the bisphenol A is hydroxylated to form 2,2-bis(4-hydroxyphenyl)-1-propanol, which is slowly biotransformed to 2,3-bis(4-hydroxyphenyl)-1,2-propanediol. Cells that were grown on bisphenol A degraded a variety of bisphenol alkanes, hydroxylated benzoic acids, and hydroxylated acetophenones during resting-cell assays. Transmission electron microscopy of cells grown on bisphenol A revealed lipid storage granules and intracytoplasmic membranes.

  6. Validity of Monod kinetics at different sludge ages--peptone biodegradation under aerobic conditions.

    PubMed

    Orhon, Derin; Cokgor, Emine Ubay; Insel, Guclu; Karahan, Ozlem; Katipoglu, Tugce

    2009-12-01

    The study presented an evaluation of the effect of culture history (sludge age) on the growth kinetics of a mixed culture grown under aerobic conditions. It involved an experimental setup where a lab-scale sequencing batch reactor was operated at steady-state at two different sludge ages (theta(X)) of 2 and 10 days. The system sustained a mixed culture fed with a synthetic substrate mainly consisting of peptone. The initial concentration of substrate COD was selected around 500 mg COD/L. Polyhydroxyalkanoate (PHA) storage occurred to a limited extent, around 30 mg COD/L for theta(X)=10 days and 15 mg COD/L for theta(X)=2 days. Evaluation of the experimental data based on calibration of two different models provided consistent and reliable evidence for a variable Monod kinetics where the maximum specific growth rate, was assessed as 6.1/day for theta(X)=2 days and 4.1/day for theta(X)=10 days. A similar variability was also applicable for the hydrolysis and storage kinetics. The rate of storage was significantly lower than the levels reported in the literature, exhibiting the ability of the microorganisms to regulate their metabolic mechanisms for adjusting the rate of microbial growth and storage competing for the same substrate. This adjustment evidently resulted in case-specific, variable kinetics both for microbial growth and substrate storage.

  7. Biodegradation of disinfection byproducts as a potential removal process during aquifer storage recovery

    USGS Publications Warehouse

    Landmeyer, J.E.; Bradley, P.M.; Thomas, J.M.

    2000-01-01

    The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of tri-halomethanes in drinking water.The biodegradation potential of two drinking water disinfection byproducts was investigated using aquifer materials obtained from approximately 100 and 200 meters below land surface in an aerobic aquifer system undergoing aquifer storage recovery of treated surface water. No significant biodegradation of a model trihalomethane compound, chloroform, was observed in aquifer microcosms under aerobic or anaerobic conditions. In contrast, between 16 and 27 percent mineralization of a radiolabeled model haloacetic acid compound, chloroacetic acid, was observed. These results indicate that although the potential for biodegradation of chloroacetic acid exists in deep aquifer systems, chloroform entrained within these aquifers or formed in situ will tend to persist. These results have important implications for water managers planning to meet anticipated lowered permissible levels of trihalomethanes in drinking water.Aquifer-storage-recovery injection water often contains disinfection byproducts. Results are presented from a study in which two model disinfection

  8. Influence of organic and inorganic growth supplements on the aerobic biodegradation of chlorobenzoic acids.

    PubMed

    Fava, F; Armenante, P M; Kafkewitz, D; Marchetti, L

    1995-04-01

    The effect of yeast extract and its less complex substituents on the rate of aerobic dechlorination of 2-chlorobenzoic acid (2-ClBZOH) and 2,5-dichlorobenzoic acid (2,5-Cl2BZOH) by Pseudomonas sp. CPE2 strain, and of 3-chlorobenzoic acid (3-ClBZOH), 4-chlorobenzoic acid (4-ClBZOH) and 3,4-dichlorobenzoic acid (3,4-Cl2BZOH) by Alcaligenes sp. CPE3 strain were investigated. Yeast extract at 50 mg/l increased the average dechlorination rate of 200 mg/l of 4-ClBZOH, 2,5-Cl2BZOH, 3,4-Cl2BZOH, 3-ClBZOH and 2-ClBZOH by about 75%, 70%, 55%, 7%, and 1%, respectively. However, in the presence of yeast extract the specific dechlorination activity of CPE2 and CPE3 cells (per unit biomass) was always lower than without yeast extract, although it increased significantly during the exponential growth phase. When a mixed vitamin solution or a mixed trace element solution was used instead of yeast extract the rate of 4-ClBZOH dechlorination increased by 30%-35%, whereas the rate of 2,5-Cl2BZOH and 3,4-Cl2BZOH dechlorination increased by only 2%-10%. The presence of vitamins or trace elements also resulted in a specific dechlorination activity that was generally higher than that observed for the same cells grown solely on chlorobenzoic acid. The results of this work indicate that yeast extract, a complex mixture of readily oxidizable carbon sources, vitamins, and trace elements, enhances the growth and the dechlorination activity of CPE2 and CPE3 cells, thus resulting in an overall increase in the rate of chlorobenzoic acid utilization and dechlorination.

  9. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    NASA Astrophysics Data System (ADS)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    's surface area, they have a profound influence on the biogeochemistry of the planet. This is evident from the observation that the O2 and CH4 content of Earth's atmosphere are in extreme disequilibrium (Sagan et al., 1993). The combination of high aerobic primary production and anoxic sediments provided the large deposits of fossil fuels that have become vital and contentious sources of energy for modern industrialized societies. Anaerobic metabolism is responsible for the abundance of N2 in the atmosphere; otherwise N2-fixing bacteria would have consumed most of the N2 pool long ago (Schlesinger, 1997). Anaerobic microorganisms are common symbionts of termites, cattle, and many other animals, where they aid digestion. Nutrient and pollutant chemistry are strongly modified by the reduced conditions that prevail in wetland and aquatic ecosystems.This review of anaerobic metabolism emphasizes aerobic oxidation, because the two processes cannot be separated in a complete treatment of the topic. It is process oriented and highlights the fascinating microorganisms that mediate anaerobic biogeochemistry. We begin this review with a brief discussion of CO2 assimilation by autotrophs, the source of most of the reducing power on Earth, and then consider the biological processes that harness this potential energy. Energy liberation begins with the decomposition of organic macromolecules to relatively simple compounds, which are simplified further by fermentation. Methanogenesis is considered next because CH4 is a product of acetate fermentation, and thus completes the catabolism of organic matter, particularly in the absence of inorganic electron acceptors. Finally, the organisms that use nitrogen, manganese, iron, and sulfur for terminal electron acceptors are considered in order of decreasing free-energy yield of the reactions.

  10. Biodegradation of naphthenic acids in oils sands process waters in an immobilized soil/sediment bioreactor.

    PubMed

    McKenzie, Natalie; Yue, Siqing; Liu, Xudong; Ramsay, Bruce A; Ramsay, Juliana A

    2014-08-01

    Aqueous extraction of bitumen in the Alberta oil sands industry produces large volumes of oil sands process water (OSPW) containing naphthenic acids (NAs), a complex mixture of carboxylic acids that are acutely toxic to aquatic organisms. Although aerobic biodegradation reduces NA concentrations and OSPW toxicity, treatment times are long, however, immobilized cell reactors have the potential to improve NA removal rates. In this study, two immobilized soil/sediment bioreactors (ISBRs) operating in series were evaluated for treatment of NAs in OSPW. A biofilm was established from microorganisms associated with sediment particles from an OSPW contaminated wetland on a non-woven textile. At 16 months of continuous operation with OSPW as the sole source of carbon and energy, 38±7% NA removal was consistently achieved at a residence time of 160 h at a removal rate of 2.32 mg NAs L(-1)d(-1). The change in NA profile measured by gas chromatography-mass spectrometry indicated that biodegradability decreased with increasing cyclicity. These results indicate that such treatment can significantly reduce NA removal rates compared to most studies, and the treatment of native process water in a bioreactor has been demonstrated. Amplification of bacterial 16S rRNA genes and sequencing using Ion Torrent sequencing characterized the reactors' biofilm populations and found as many as 235 and 198 distinct genera in the first and second bioreactor, respectively, with significant populations of ammonium- and nitrite-oxidizers.

  11. Non-biodegradable landfill leachate treatment by combined process of agitation, coagulation, SBR and filtration

    SciTech Connect

    Abood, Alkhafaji R.; Bao, Jianguo; Du, Jiangkun; Zheng, Dan; Luo, Ye

    2014-02-15

    Highlights: • A novel method of stripping (agitation) was investigated for NH{sub 3}-N removal. • PFS coagulation followed agitation process enhanced the leachate biodegradation. • Nitrification–denitrification achieved by changing operation process in SBR treatment. • A dual filter of carbon-sand is suitable as a polishing treatment of leachate. • Combined treatment success for the complete treatment of non-biodegradable leachate. - Abstract: This study describes the complete treatment of non-biodegradable landfill leachate by combined treatment processes. The processes consist of agitation as a novel stripping method used to overcome the ammonia toxicity regarding aerobic microorganisms. The NH{sub 3}-N removal ratio was 93.9% obtained at pH 11.5 and a gradient velocity (G) 150 s{sup −1} within a five-hour agitation time. By poly ferric sulphate (PFS) coagulation followed the agitation process; chemical oxygen demand (COD) and biological oxygen demand (BOD{sub 5}) were removed at 70.6% and 49.4%, respectively at an optimum dose of 1200 mg L{sup −1} at pH 5.0. The biodegradable ratio BOD{sub 5}/COD was improved from 0.18 to 0.31 during pretreatment step by agitation and PFS coagulation. Thereafter, the effluent was diluted with sewage at a different ratio before it was subjected to sequencing batch reactor (SBR) treatment. Up to 93.3% BOD{sub 5}, 95.5% COD and 98.1% NH{sub 3}-N removal were achieved by SBR operated under anoxic–aerobic–anoxic conditions. The filtration process was carried out using sand and carbon as a dual filter media as polishing process. The final effluent concentration of COD, BOD{sub 5}, suspended solid (SS), NH{sub 3}-N and total organic carbon (TOC) were 72.4 mg L{sup −1}, 22.8 mg L{sup −1}, 24.2 mg L{sup −1}, 18.4 mg L{sup −1} and 50.8 mg L{sup −1} respectively, which met the discharge standard. The results indicated that a combined process of agitation-coagulation-SBR and filtration effectively eliminated

  12. GUIDE FOR CONDUCTING TREATABILITY STUDIES UNDER CERCLA: AEROBIC BIODEGRADATION REMEDY SCREENING

    EPA Science Inventory

    Systematically conducted, well-documented treatability studies are an important component of the remedial investigation/feasibility study (KU FS) process and the remedial design/remedial action (RD/RA) process under the Comprehensive Environmental Response, Compensation, and L...

  13. Biodegradation of PAH`s in sediment-slurry processes

    SciTech Connect

    Hughes, J.B.; Beckles, D.; Chandra, S.

    1995-12-31

    The focus of this research was to examine biodegradation of polynuclear aromatic hydrocarbons (PAHs) in lab scale slurry reactors. The studies summarized in this paper focused on the rate and extent of contaminant release from the sediments, oxygen demand of anaerobic sediments, and the rate and extent of PAH biodegradation achieved. Mass balances were used in all cases. The studies identified several factors which may influence the design or operation of bioreactors used for sediment remediation. Mixing had the greatest effect on the rate and extent of contaminant release; solids loading and aeration had little or no effect in mixed reactors. In unmixed reactors, aerated systems showed faster rates of contaminant release than unaerated systems, indicating that the aeration process itself provides some degree of mixing. The maximum extent of mineralization appeared to be reached within five days in mixed systems; significantly lower mineralization was seen in reactors with insufficient mixing.

  14. A single aerobic exercise session accelerates movement execution but not central processing.

    PubMed

    Beyer, Kit B; Sage, Michael D; Staines, W Richard; Middleton, Laura E; McIlroy, William E

    2017-03-27

    Previous research has demonstrated that aerobic exercise has disparate effects on speed of processing and movement execution. In simple and choice reaction tasks, aerobic exercise appears to increase speed of movement execution while speed of processing is unaffected. In the flanker task, aerobic exercise has been shown to reduce response time on incongruent trials more than congruent trials, purportedly reflecting a selective influence on speed of processing related to cognitive control. However, it is unclear how changes in speed of processing and movement execution contribute to these exercise-induced changes in response time during the flanker task. This study examined how a single session of aerobic exercise influences speed of processing and movement execution during a flanker task using electromyography to partition response time into reaction time and movement time, respectively. Movement time decreased during aerobic exercise regardless of flanker congruence but returned to pre-exercise levels immediately after exercise. Reaction time during incongruent flanker trials decreased over time in both an aerobic exercise and non-exercise control condition indicating it was not specifically influenced by exercise. This disparate influence of aerobic exercise on movement time and reaction time indicates the importance of partitioning response time when examining the influence of aerobic exercise on speed of processing. The decrease in reaction time over time independent of aerobic exercise indicates that interpreting pre-to-post exercise changes in behavior requires caution.

  15. Impact of heavy metals on the oil products biodegradation process.

    PubMed

    Zukauskaite, Audrone; Jakubauskaite, Viktorija; Belous, Olga; Ambrazaitiene, Dalia; Stasiskiene, Zaneta

    2008-12-01

    Oil products continue to be used as a principal source of energy. Wide-scale production, transport, global use and disposal of petroleum have made them major contaminants in prevalence and quantity in the environment. In accidental spills, actions are taken to remove or remediate or recover the contaminants immediately, especially if they occur in environmentally sensitive areas, for example, in coastal zones. Traditional methods to cope with oil spills are confined to physical containment. Biological methods can have an advantage over the physical-chemical treatment regimes in removing spills in situ as they offer biodegradation of oil fractions by the micro-organisms. Recently, biological methods have been known to play a significant role in bioremediation of oil-polluted coastal areas. Such systems are likely to be of significance in the effective management of sensitive coastal ecosystems chronically subjected to oil spillage. For this reason the aim of this paper is to present an impact of Mn, Cu, Co and Mo quantities on oil biodegradation effectiveness in coastal soil and to determine the relationship between metal concentrations and degradation of two oil products (black oil and diesel fuel). Soil was collected in the Baltic Sea coastal zone oil products degradation area (Klaipeda, Lithuania). The experiment consisted of two parts: study on the influence of micro-elements on the oil product biodegradation process; and analysis of the influence of metal concentration on the number of HDMs. The analysis performed and results obtained address the following areas: impact of metal on a population of hydrocarbon degrading micro-organisms, impact of metals on residual concentrations of oil products, influence of metals on the growth of micro-organisms, inter-relation of metal concentrations with degradation rates. Statistical analysis was made using ;Statgraphics plus' software. The influence of metals on the growth of micro-organisms, the biodegradation process

  16. Combined Fenton oxidation and aerobic biological processes for treating a surfactant wastewater containing abundant sulfate.

    PubMed

    Wang, Xiao-Jun; Song, Yang; Mai, Jun-Sheng

    2008-12-30

    The present study is to investigate the treatment of a surfactant wastewater containing abundant sulfate by Fenton oxidation and aerobic biological processes. The operating conditions have been optimized. Working at an initial pH value of 8, a Fe2+ dosage of 600mgL(-1) and a H2O2 dosage of 120mgL(-1), the chemical oxidation demand (COD) and linear alkylbenzene sulfonate (LAS) were decreased from 1500 and 490mgL(-1) to 230 and 23mgL(-1) after 40min of Fenton oxidation, respectively. Advanced oxidation pretreatment using Fenton reagent was very effective at enhancing the biodegradability of this kind of wastewater. The wastewater was further treated by a bio-chemical treatment process based on an immobilized biomass reactor with a hydraulic detention time (HRT) of 20h after Fenton oxidation pretreatment under the optimal operating conditions. It was found that the COD and LAS of the final effluent were less than 100 and 5mgL(-1), corresponding to a removal efficiencies of over 94% and 99%, respectively.

  17. Aerobic Digestion. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Klopping, Paul H.

    This manual contains the textual material for a single-lesson unit on aerobic sludge digestion. Topic areas addressed include: (1) theory of aerobic digestion; (2) system components; (3) performance factors; (4) indicators of stable operation; and (5) operational problems and their solutions. A list of objectives, glossary of key terms, and…

  18. Metaproteomics reveals major microbial players and their biodegradation functions in a large-scale aerobic composting plant.

    PubMed

    Liu, Dongming; Li, Mingxiao; Xi, Beidou; Zhao, Yue; Wei, Zimin; Song, Caihong; Zhu, Chaowei

    2015-11-01

    Composting is an appropriate management alternative for municipal solid waste; however, our knowledge about the microbial regulation of this process is still scare. We employed metaproteomics to elucidate the main biodegradation pathways in municipal solid waste composting system across the main phases in a large-scale composting plant. The investigation of microbial succession revealed that Bacillales, Actinobacteria and Saccharomyces increased significantly with respect to abundance in composting process. The key microbiologic population for cellulose degradation in different composting stages was different. Fungi were found to be the main producers of cellulase in earlier phase. However, the cellulolytic fungal communities were gradually replaced by a purely bacterial one in active phase, which did not support the concept that the thermophilic fungi are active through the thermophilic phase. The effective decomposition of cellulose required the synergy between bacteria and fungi in the curing phase.

  19. Metaproteomics reveals major microbial players and their biodegradation functions in a large-scale aerobic composting plant

    PubMed Central

    Liu, Dongming; Li, Mingxiao; Xi, Beidou; Zhao, Yue; Wei, Zimin; Song, Caihong; Zhu, Chaowei

    2015-01-01

    Composting is an appropriate management alternative for municipal solid waste; however, our knowledge about the microbial regulation of this process is still scare. We employed metaproteomics to elucidate the main biodegradation pathways in municipal solid waste composting system across the main phases in a large-scale composting plant. The investigation of microbial succession revealed that Bacillales, Actinobacteria and Saccharomyces increased significantly with respect to abundance in composting process. The key microbiologic population for cellulose degradation in different composting stages was different. Fungi were found to be the main producers of cellulase in earlier phase. However, the cellulolytic fungal communities were gradually replaced by a purely bacterial one in active phase, which did not support the concept that the thermophilic fungi are active through the thermophilic phase. The effective decomposition of cellulose required the synergy between bacteria and fungi in the curing phase. PMID:25989417

  20. Two-stage process combines anaerobic and aerobic methods

    SciTech Connect

    Kayhanian, M.; Lindenauer, K.; Hardy, S.; Tchobanoglous, G.

    1991-03-01

    The organic fraction of the material diverted from landfills has potential to be utilized as a raw material to be recycled, used for the production of compost, converted to energy in waste-to-energy facilities, or used for the production of other end products. Given the uncertainties concerning the future availability, production costs, and market prices for conventional fuels, any potential source of alternate energy and alternative energy technologies deserve serious consideration. Faced with an uncertain energy future, several European countries have already started using biomass and MSW as a source of energy. An innovative high-solids anaerobic digestion/aerobic composting process currently under investigation at the University of California, Davis is as an ideal candidate for processing a large fraction of the organic matter in MSW. The principal advantages of this innovative process which is described and discussed in this paper are: (1) the recovery of biogas that can be used as a fuel for the production of energy, and (2) the production of humus-like material that can be used as a high-quality soil amendment or as boiler fuel. The fact that a liquid waste stream that needs further treatment is not generated in this process is another significant advantage.

  1. Model coupling intraparticle diffusion/sorption, nonlinear sorption, and biodegradation processes

    USGS Publications Warehouse

    Karapanagioti, Hrissi K.; Gossard, Chris M.; Strevett, Keith A.; Kolar, Randall L.; Sabatini, David A.

    2001-01-01

    Diffusion, sorption and biodegradation are key processes impacting the efficiency of natural attenuation. While each process has been studied individually, limited information exists on the kinetic coupling of these processes. In this paper, a model is presented that couples nonlinear and nonequilibrium sorption (intraparticle diffusion) with biodegradation kinetics. Initially, these processes are studied independently (i.e., intraparticle diffusion, nonlinear sorption and biodegradation), with appropriate parameters determined from these independent studies. Then, the coupled processes are studied, with an initial data set used to determine biodegradation constants that were subsequently used to successfully predict the behavior of a second data set. The validated model is then used to conduct a sensitivity analysis, which reveals conditions where biodegradation becomes desorption rate-limited. If the chemical is not pre-equilibrated with the soil prior to the onset of biodegradation, then fast sorption will reduce aqueous concentrations and thus biodegradation rates. Another sensitivity analysis demonstrates the importance of including nonlinear sorption in a coupled diffusion/sorption and biodegradation model. While predictions based on linear sorption isotherms agree well with solution concentrations, for the conditions evaluated this approach overestimates the percentage of contaminant biodegraded by as much as 50%. This research demonstrates that nonlinear sorption should be coupled with diffusion/sorption and biodegradation models in order to accurately predict bioremediation and natural attenuation processes. To our knowledge this study is unique in studying nonlinear sorption coupled with intraparticle diffusion and biodegradation kinetics with natural media.

  2. Processing and characterization of novel biobased and biodegradable materials

    NASA Astrophysics Data System (ADS)

    Pilla, Srikanth

    Human society has benefited tremendously from the use of petroleum-based plastics. However, there are growing concerns with their adverse environmental impacts and volatile costs attributed to the skyrocketing oil prices. Additionally most of the petroleum-based polymers are non-biodegradable causing problems about their disposal. Thus, during the last couple of decades, scientists ail over the world have been focusing on developing new polymeric materials that are biobased and biodegradable, also termed as green plastics . This study aims to develop green materials based on polylactide (PLA) biopolymer that can be made from plants. Although PLA can provide important advantages in terms of sustainability and biodegradability, it has its own challenges such as high cost, brittleness, and narrow processing window. These challenges are addressed in this study by investigating both new material formulations and processes. To improve the material properties and control the material costs, PLA was blended with various fillers and modifiers. The types of fillers investigated include carbon nanotube (CNT) nanoparticles and various natural fibers such as pine-wood four, recycled-wood fibers and flax fiber. Using natural fibers as fillers for PLA can result in fully biodegradable and eco-friendly biocomposites. Also due to PLA's sensitivity to moisture and temperature, molecular degradation can occur during processing leading to inferior material properties. To address this issue, one of the approaches adopted by this study was to incorporate a multifunctional chain-extender into PLA, which increased the molecular weight of PLA thereby improving the material properties. To improve the processability and reduce the material cost, both microcellular injection molding and extrusion processes have been studied. The microcellular technology allows the materials to be processed at a lower temperature, which is attractive for thermo- and moisture-sensitive materials like PLA. They

  3. Comparison of aerobic and anaerobic stability indices through a MSW biological treatment process.

    PubMed

    Ponsá, Sergio; Gea, Teresa; Alerm, Llorenç; Cerezo, Javier; Sánchez, Antoni

    2008-12-01

    A complex mechanical-biological waste treatment plant designed for the processing of mixed municipal solid wastes (MSW) and source-selected organic fraction of municipal solid wastes (OFMSW) has been studied by using stability indices related to aerobic (respiration index, RI) and anaerobic conditions (biochemical methane potential, BMP). Several selected stages of the plant have been characterized: waste inputs, mechanically treated wastes, anaerobically digested materials and composted wastes, according to the treatment sequence used in the plant. Results obtained showed that the main stages responsible for waste stabilization were the two first stages: mechanical separation and anaerobic digestion with a diminution of both RI and BMP around 40% and 60%, respectively, whereas the third stage, composting of digested materials, produced lesser biological degradation (20-30%). The results related to waste stabilization were similar in both lines (MSW and OFMSW), although the indices obtained for MSW were significantly lower than those obtained for OFMSW, which demonstrated a high biodegradability of OFMSW. The methodology proposed can be used for the characterization of organic wastes and the determination of the efficiency of operation units used in mechanical-biological waste treatment plants.

  4. Aerobic Biodegradation of Trichloroethylene.

    DTIC Science & Technology

    1987-07-01

    the meta ring-fission product , the supernatant solution of phenol- induced restTW cells incubated with catechol and 3-methylcatechol was examined ...into C02 and unidentified nonvolatile products . Phenol, 41 toiin- andq-cresol were found to replace the site water requirement for TCE metabolism...undertaken in an effort to discover microorganisms capable of degrading TCE to innocuous products . Isolation of a microorganism with TCE-degrading ability

  5. The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC) Treatment by 454-Pyrosequencing.

    PubMed

    Wei, Chao; He, Wenjie; Wei, Li; Li, Chunying; Ma, Jun

    2015-01-01

    In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O) integrated process for the treatment of petrochemical nanofiltration concentrate (NFC) wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A) and aerobic biofilm (Sample O), 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH) biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB) Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN) on average were 90.51% and 75.11% during the entire treatment process.

  6. The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC) Treatment by 454-Pyrosequencing

    PubMed Central

    Wei, Chao; He, Wenjie; Wei, Li; Li, Chunying; Ma, Jun

    2015-01-01

    In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O) integrated process for the treatment of petrochemical nanofiltration concentrate (NFC) wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A) and aerobic biofilm (Sample O), 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH) biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB) Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN) on average were 90.51% and 75.11% during the entire treatment process. PMID:26461260

  7. High-risk biodegradable waste processing by alkaline hydrolysis.

    PubMed

    Kalambura, Sanja; Voća, Neven; Krička, Tajana; Sindrak, Zoran; Spehar, Ana; Kalambura, Dejan

    2011-09-01

    Biodegradable waste is by definition degraded by other living organisms. Every day, meat industry produces large amounts of a specific type of biodegradable waste called slaughterhouse waste. Traditionally in Europe, this waste is recycled in rendering plants which produce meat and bone meal and fat. However, feeding animals with meat and bone meal has been banned since the outbreaks of bovine spongiform encephalopathy (BSE). In consequence, new slaughterhouse waste processing technologies have been developed, and animal wastes have now been used for energy production. Certain parts of this waste, such as brains and spinal cord, are deemed high-risk substances, because they may be infected with prions. Their treatment is therefore possible only in strictly controlled conditions. One of the methods which seems to bear acceptable health risk is alkaline hydrolysis. This paper presents the results of an alkaline hydrolysis efficiency study. It also proposes reuse of the obtained material as organic fertiliser, as is suggested by the analytical comparison between meat and bone meal and hydrolysate.

  8. Aerobic MTBE biodegradation in the presence of BTEX by two consortia under batch and semi-batch conditions.

    PubMed

    Raynal, M; Pruden, A

    2008-04-01

    This study explores the effect of microbial consortium composition and reactor configuration on methyl tert-butyl ether (MTBE) biodegradation in the presence of benzene, toluene, ethylbenzene and p-xylenes(BTEX). MTBE biodegradation was monitored in the presence and absence of BTEX in duplicate batch reactors inoculated with distinct enrichment cultures: MTBE only (MO-originally enriched on MTBE) and/or MTBE BTEX (MB-originally enriched on MTBE and BTEX). The MO culture was also applied in a semi-batch reactor which received both MTBE and BTEX periodically in fresh medium after allowing cells to settle. The composition of the microbial consortia was explored using a combination of 16S rRNA gene cloning and quantitative polymerase chain reaction targeting the known MTBE-degrading strain PM1T. MTBE biodegradation was completely inhibited by BTEX in the batch reactors inoculated with the MB culture, and severely retarded in those inoculated with the MO culture (0.18+/-0.04 mg/L-day). In the semi-batch reactor, however, the MTBE biodegradation rate in the presence of BTEX was almost three times as high as in the batch reactors (0.48+/-0.2 mg/L-day), but still slower than MTBE biodegradation in the absence of BTEX in the MO-inoculated batch reactors (1.47+/-0.47 mg/L-day). A long lag phase in MTBE biodegradation was observed in batch reactors inoculated with the MB culture (20 days), but the ultimate rate was comparable to the MO culture (0.95+/-0.44 mg/L-day). Analysis of the cultures revealed that strain PM1T concentrations were lower in cultures that successfully biodegraded MTBE in the presence of BTEX. Also, other MTBE degraders, such as Leptothrix sp. and Hydrogenophaga sp. were found in these cultures. These results demonstrate that MTBE bioremediation in the presence of BTEX is feasible, and that culture composition and reactor configuration are key factors.

  9. Application of H2O and UV/H2O2 processes for enhancing the biodegradability of reactive black 5 dye.

    PubMed

    Kalpana, S Divya; Kalyanaraman, Chitra; Gandhi, N Nagendra

    2011-07-01

    Leather processing is a traditional activity in India during which many organic and inorganic chemicals are added while part of it is absorbed by the leather, the remaining chemicals are discharged along with the effluent. The effluent contains both easily biodegradable and not easily biodegradable synthetic organics like dyes, syntans. Easily biodegradable organics are removed in the existing biological treatment units whereas synthetic organics present in the wastewater are mostly adsorbed over the microbes. As the tannery effluent contains complex chemicals, it is difficult to ascertain the degradation of specific pollutants. To determine the increase in the biodegradability, one of the complex and synthetic organic chemical like dye used in the tanning operation was selected for Advanced Oxidation Process (AOPs) treatment for cleaving complex organics and its subsequent treatment in aerobic process. In the present study, Reactive Black 5 Dye used in the tanning operation was selected for Hydrogen Peroxide (H2O2) and UV/H2O2 pre-treatment for different operating conditions like pH, contact time and different volume of H2O2. A comparison was made between the untreated, Hydrogen Peroxide (H2O2) and UV/H2O2 treated effluent in order to ascertain the influence of AOP on the improvement of biodegradability of effluent. An increase in the BOD5/COD ratio from 0.21 to 0.435 was achieved in the UV/H2O2 pre-treatment process. This pre-treated effluent was further subjected to aerobic process. Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) removal efficiency of the UV/H2O2 pre-treated dye solution in the aerobic process was found to be 86.39% and 77.82% when compared to 52.43% of BOD5 and 51.55% of COD removal efficiency without any pre-treatment. Hence from these results, to increase the biodegradability of Reactive Black 5 dye pre-treatment methods like H2O2 and UV/H2O2 can be used prior to biological treatment process.

  10. Wet air oxidation induced enhanced biodegradability of distillery effluent.

    PubMed

    Malik, S N; Saratchandra, T; Tembhekar, P D; Padoley, K V; Mudliar, S L; Mudliar, S N

    2014-04-01

    The present study reports the feasibility of Wet Air Oxidation (WAO) as a pretreatment option for enhanced biodegradation of complex distillery effluent. Initially, the distillery effluent was pretreated by WAO at different process conditions (pressure, temperature and time) to facilitate enhancement in the biodegradability index (BI = BOD5: COD ratio). The biodegradability of WAO pretreated effluent was evaluated by subjecting it to aerobic biodegradation and anaerobic followed by aerobic biodegradation. Aerobic biodegradation of pretreated effluent with enhanced biodegradability index (BI = 0.4-0.8) showed enhanced COD reduction of up to 67.7%, whereas the untreated effluent (BI = 0.17) indicated poor COD reduction of only 22.5%. Anaerobic followed by aerobic biodegradation of pretreated effluent has shown up to 87.9% COD reduction, while the untreated effluent has shown only 43.1% COD reduction. Bio-kinetic parameters also confirmed the increased rate of bio-oxidation at enhanced BIs. The results indicate that the WAO pretreatment facilitates enhanced bio-oxidation/bio-degradation of complex effluents like the distillery spent wash.

  11. Central Role of Dynamic Tidal Biofilms Dominated by Aerobic Hydrocarbonoclastic Bacteria and Diatoms in the Biodegradation of Hydrocarbons in Coastal Mudflats

    PubMed Central

    Coulon, Frédéric; Chronopoulou, Panagiota-Myrsini; Fahy, Anne; Païssé, Sandrine; Goñi-Urriza, Marisol; Peperzak, Louis; Acuña Alvarez, Laura; McKew, Boyd A.; Brussaard, Corina P. D.; Underwood, Graham J. C.; Timmis, Kenneth N.; Duran, Robert

    2012-01-01

    Mudflats and salt marshes are habitats at the interface of aquatic and terrestrial systems that provide valuable services to ecosystems. Therefore, it is important to determine how catastrophic incidents, such as oil spills, influence the microbial communities in sediment that are pivotal to the function of the ecosystem and to identify the oil-degrading microbes that mitigate damage to the ecosystem. In this study, an oil spill was simulated by use of a tidal chamber containing intact diatom-dominated sediment cores from a temperate mudflat. Changes in the composition of bacteria and diatoms from both the sediment and tidal biofilms that had detached from the sediment surface were monitored as a function of hydrocarbon removal. The hydrocarbon concentration in the upper 1.5 cm of sediments decreased by 78% over 21 days, with at least 60% being attributed to biodegradation. Most phylotypes were minimally perturbed by the addition of oil, but at day 21, there was a 10-fold increase in the amount of cyanobacteria in the oiled sediment. Throughout the experiment, phylotypes associated with the aerobic degradation of hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs) (Cycloclasticus) and alkanes (Alcanivorax, Oleibacter, and Oceanospirillales strain ME113), substantively increased in oiled mesocosms, collectively representing 2% of the pyrosequences in the oiled sediments at day 21. Tidal biofilms from oiled cores at day 22, however, consisted mostly of phylotypes related to Alcanivorax borkumensis (49% of clones), Oceanospirillales strain ME113 (11% of clones), and diatoms (14% of clones). Thus, aerobic hydrocarbon biodegradation is most likely to be the main mechanism of attenuation of crude oil in the early weeks of an oil spill, with tidal biofilms representing zones of high hydrocarbon-degrading activity. PMID:22407688

  12. Fenton's oxidation process for phenolic wastewater remediation and biodegradability enhancement.

    PubMed

    Martins, Rui C; Rossi, André F; Quinta-Ferreira, Rosa M

    2010-08-15

    A mixture of six phenolic acids, corresponding to an initial TOC of 370 mgC/L, was studied by Fenton's peroxidation aiming to improve the biodegradability of agro-industrial wastewaters. Input operating variables including the concentration of pollutants, iron and hydrogen peroxide as well as the reaction time were used to assess the mineralization degree through a factorial experimental methodology. A TOC removal in the range of 15.0-58.8% was attained within the operational conditions used. A reduced model was achieved using the statistically important independent factors and interactions to predict TOC degradation. On the hydrogen peroxide injection methodology, the results showed that the continuous introduction of small volumes is advantageous when compared with one single addition of the overall volume at the zero reaction time with a mineralization improvement of 11%. The use of FeSO(4).7H(2)O correspondent to a Fe(2+) load of 271 mg; [H(2)O(2)]=488.0 mM, injected in twelve aliquots each 30 min during 6h of reaction reached optimal efficiencies with the parent compounds (quantified by HPLC and the Folin-Ciocalteau method) quickly totally removed and TOC, COD and BOD(5) final values of 123 mgC/L, 180 mgO(2)/L and 146 mgO(2)/L, respectively. Toxicity assessment by Vibrio fischeri light inhibition revealed that Fenton's process reduces the effluent ecological impact related with the decomposition of the toxic phenolic acids. Indeed, EC(50) changed from 32.2% dilution to no-dilution needed. The analysis of BOD(5)/COD ratio pointed out a high improvement of the treated wastewater biodegradability from 0.30 to 0.80 meaning that the application of Fenton's oxidation as a pre-treatment enables a further application of an efficient post-biological technology which was also confirmed by respirometry.

  13. Comparison of Sampling Methods to Determine the Impact of Aerobic Biodegradation on Benzene Concentrations at UST Sites

    EPA Science Inventory

    This material will be interesting to regulators and contractors who collect samples of soil gas to estimate the potential for vapor intrusion of buildings. In the absence of biodegradation, transport of vapors through the unsaturated zone is expected to be by diffusion, and t...

  14. Effects of pH on aquatic biodegradation processes

    NASA Astrophysics Data System (ADS)

    Krachler, R. F.; Krachler, R.; Stojanovic, A.; Wielander, B.; Herzig, A.

    2009-01-01

    To date, little is known about the pH-stimulated mineralization of organic matter in aquatic environments. In this study, we investigated biodegradation processes in alkaline waters. Study site is a large shallow soda lake in Central Europe (Neusiedler See/Ferto). The decomposition rate of plant litter was measured as a function of pH by incubating air-saturated lake-water samples in contact with Phragmites litter (leaves) from the littoral vegetation. All samples showed high decomposition rates (up to 32% mass loss within 35 days) and a characteristic two-step degradation mechanism. During the degradation process, the solid plant litter was dissolved forming humic colloids. Subsequently, the humic colloids were mineralized to CO2 in the water column. The decomposition rate was linearly related to pH. Increasing pH values accelerated significantly the leaching of humic colloids as well as the final degradation process. The observed two-step mechanism controls the wetland/lake/air carbon fluxes, since large quantities of humic colloids are currently produced in the reed belt, exported through wind-driven circulations and incorporated into the open lake foodweb. At present, the lake is rapidly shrinking due to peat deposition in the littoral zone, whereas it has been resistant to silting-up processes for thousands of years. In order to investigate the cause of this abrupt change, the chemical composition of the lake-water was measured during 1995-2007. A thorough analysis of these data revealed that major lake-water discharges through the lake's artificial outlet channel led to a decline in salinity and alkalinity. According to our estimates, the lake's original salinity and alkalinity was 70-90% higher compared to the present conditions, with the consequence of substantially lower pH values in the present lake. The observed pH dependence of reed litter biodegradation rates points to a causal connection between low pH values and accumulation of peat in the lake basin

  15. Captopril and its dimer captopril disulfide: photodegradation, aerobic biodegradation and identification of transformation products by HPLC-UV and LC-ion trap-MS(n).

    PubMed

    Mahmoud, Waleed M M; Kümmerer, Klaus

    2012-08-01

    In some countries effluents from hospitals and households are directly emitted into open ditches without any further treatment and with very little dilution. Under such circumstances photo- and biodegradation in the environment can occur. However, these processes do not necessarily end up with the complete mineralization of a chemical. Therefore, the biodegradability of photoproduct(s) by environmental bacteria is of interest. Cardiovascular diseases are the number one cause of death globally. Captopril (CP) is used in this study as it is widely used in Egypt and stated as one of the essential drugs in Egypt for hypertension. Three tests from the OECD series were used for biodegradation testing: Closed Bottle test (CBT; OECD 301 D), Manometric Respirometry test (MRT; OECD 301 F) and the modified Zahn-Wellens test (ZWT; OECD 302 B). Photodegradation (150 W medium-pressure Hg-lamp) of CP was studied. Also CBT was performed for captopril disulfide (CPDS) and samples received after 64 min and 512 min of photolysis. The primary elimination of CP and CPDS was monitored by LC-UV at 210 nm and structures of photoproducts were assessed by LC-UV-MS/MS (ion trap). Analysis of photodegradation samples by LC-MS/MS revealed CP sulfonic acid as the major photodegradation product of CP. No biodegradation was observed for CP, CPDS and of the mixture resulting from photo-treatment after 64 min in CBT. Partial biodegradation in the CBT and MRT was observed in samples taken after 512 min photolysis and for CP itself in MRT. Complete biodegradation and mineralization of CP occurred in the ZWT.

  16. Fates of chlorinated volatile organic compounds in aerobic biological treatment processes: the effects of aeration and sludge addition.

    PubMed

    Chen, Wei-Hsiang; Yang, Wen-Ben; Yuan, Chung-Shin; Yang, Jun-Chen; Zhao, Qing-Liang

    2014-05-01

    The emission of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) is becoming an environmental issue of increasing concern. As biological treatment has been considered as one important approach for VOC removal, lab-scale batch experiments were conducted in this study to investigate the fates of four chlorinated hydrocarbons, including chloroform, carbon tetrachloride, trichloroethylene (TCE), and tetrachloroethylene (PERC), in the biological treatment processes with respect to the effects of aeration and sludge addition. The VOC concentrations in the phases of air, water, and sludge under four simulated treatment stages (the first sedimentation, the forepart and rear part of aerobic biological treatment, and the second sedimentation) were analyzed. The results were used to understand the three-phase partitioning of these compounds and to estimate their potentials for volatilization and biological sorption and degradation in these technologies with the concept of fugacity. It was observed that the VOCs were mainly present in the water phase through the experiments. The effects of aeration or sludge addition on the fates of these VOCs occurred but appeared to be relatively limited. The concentration distributions of the VOCs were well below the reported partitioning coefficients. It was suggested that these compounds were unsaturated in the air and sludge phases, enhancing their potentials for volatilization and biological sorption/degradation through the processes. However, the properties of these chlorinated VOCs such as the volatility, polarity, or even biodegradability caused by their structural characteristics (e.g., the number of chlorine, saturated or unsaturated) may represent more significant factors for their fates in the aerobic biological treatment processes. These findings prove the complication behind the current knowledge of VOC pollutions in WWTPs and are of help to manage the adverse impacts on the environment and public

  17. Investigation of the application of an enzyme-based biodegradability test method to a municipal solid waste biodrying process.

    PubMed

    Wagland, S T; Godley, A R; Tyrrel, S F

    2011-07-01

    This paper presents a study to evaluate the recently developed enzymatic hydrolysis test (EHT) through its repeated application to a waste treatment process. A single waste treatment facility, involving a biodrying process, has been monitored using three different methods to assess the biodegradable content of the organic waste fractions. These test methods were the anaerobic BMc, aerobic DR4 and the EHT, which is a method based on the enzymatic hydrolysis of the cellulosic content of waste materials. The input municipal solid waste (MSW) and the output solid recovered fuel (SRF) and organic fines streams were sampled over a period of nine months from a single mechanical biological treatment (MBT) facility. The EHT was applied to each stream following grinding to <10 mm and <2 mm, in order to investigate the effect of particle size on the release of dissolved organic carbon (DOC) from enzyme hydrolysis. The output organic fines were found to more biodegradable than the MSW input and SRF output samples in each of the test methods, significantly (p<0.05) for the EHT and DR4 methods, on the basis of DOC released and oxygen consumed, respectively. The variation between sample replicates for the EHT was higher where sample sizes of <2 mm were analysed compared to sizes of <10 mm, and the DOC release at each phase of the EHT was observed to be higher when using particle sizes of <2 mm. Despite this, additional sample grinding from the <10 mm to a smaller particle size of <2 mm is not sufficiently beneficial to the analysis of organic waste fractions in the EHT method. Finally, it was concluded that as similar trends were observed for each test method, this trial confirms that EHT has the potential to be deployed as a practical operational biodegradability monitoring tool.

  18. Lab-scale experimental strategy for determining micropollutant partition coefficient and biodegradation constants in activated sludge.

    PubMed

    Pomiès, M; Choubert, J M; Wisniewski, C; Miège, C; Budzinski, H; Coquery, M

    2015-03-01

    The nitrifying/denitrifying activated sludge process removes several micropollutants from wastewater by sorption onto sludge and/or biodegradation. The objective of this paper is to propose and evaluate a lab-scale experimental strategy for the determination of partition coefficient and biodegradation constant for micropollutant with an objective of modelling their removal. Four pharmaceutical compounds (ibuprofen, atenolol, diclofenac and fluoxetine) covering a wide hydrophobicity range (log Kow from 0.16 to 4.51) were chosen. Dissolved and particulate concentrations were monitored for 4 days, inside two reactors working under aerobic and anoxic conditions, and under different substrate feed conditions (biodegradable carbon and nitrogen). We determined the mechanisms responsible for the removal of the target compounds: (i) ibuprofen was biodegraded, mainly under aerobic conditions by cometabolism with biodegradable carbon, whereas anoxic conditions suppressed biodegradation; (ii) atenolol was biodegraded under both aerobic and anoxic conditions (with a higher biodegradation rate under aerobic conditions), and cometabolism with biodegradable carbon was the main mechanism; (iii) diclofenac and fluoxetine were removed by sorption only. Finally, the abilities of our strategy were evaluated by testing the suitability of the parameters for simulating effluent concentrations and removal efficiency at a full-scale plant.

  19. MONITORING POLYCHLORINATED BIPHENYLS (PCBS) BIODEGRADATION USING CONTINUOUS-FLOW ISOTOPE RATIO MASS SPECTROMETRY

    EPA Science Inventory

    Research has shown that polychlorinated biphenyls (PCBs) in some cases can be removed from the environment by biodegradation. Aerobic and anaerobic biological processes have been determined in previous research to be capable of degrading PCBs. During the aerobic and anaerobic d...

  20. Monitoring biodegradation of diesel fuel in bioventing processes using in situ respiration rate.

    PubMed

    Lee, T H; Byun, I G; Kim, Y O; Hwang, I S; Park, T J

    2006-01-01

    An in situ measuring system of respiration rate was applied for monitoring biodegradation of diesel fuel in a bioventing process for bioremediation of diesel contaminated soil. Two laboratory-scale soil columns were packed with 5 kg of soil that was artificially contaminated by diesel fuel as final TPH (total petroleum hydrocarbon) concentration of 8,000 mg/kg soil. Nutrient was added to make a relative concentration of C:N:P = 100:10:1. One soil column was operated with continuous venting mode, and the other one with intermittent (6 h venting/6 h rest) venting mode. On-line O2 and CO2 gas measuring system was applied to measure O2 utilisation and CO2 production during biodegradation of diesel for 5 months. Biodegradation rate of TPH was calculated from respiration rate measured by the on-line gas measuring system. There were no apparent differences between calculated biodegradation rates from two columns with different venting modes. The variation of biodegradation rates corresponded well with trend of the remaining TPH concentrations comparing other biodegradation indicators, such as C17/pristane and C18/phytane ratio, dehydrogenase activity, and the ratio of hydrocarbon utilising bacteria to total heterotrophic bacteria. These results suggested that the on-line measuring system of respiration rate would be applied to monitoring biodegradation rate and to determine the potential applicability of bioventing process for bioremediation of oil contaminated soil.

  1. The association between aerobic fitness and language processing in children: implications for academic achievement.

    PubMed

    Scudder, Mark R; Federmeier, Kara D; Raine, Lauren B; Direito, Artur; Boyd, Jeremy K; Hillman, Charles H

    2014-06-01

    Event-related brain potentials (ERPs) have been instrumental for discerning the relationship between children's aerobic fitness and aspects of cognition, yet language processing remains unexplored. ERPs linked to the processing of semantic information (the N400) and the analysis of language structure (the P600) were recorded from higher and lower aerobically fit children as they read normal sentences and those containing semantic or syntactic violations. Results revealed that higher fit children exhibited greater N400 amplitude and shorter latency across all sentence types, and a larger P600 effect for syntactic violations. Such findings suggest that higher fitness may be associated with a richer network of words and their meanings, and a greater ability to detect and/or repair syntactic errors. The current findings extend previous ERP research explicating the cognitive benefits associated with greater aerobic fitness in children and may have important implications for learning and academic performance.

  2. Quantitative assessment of the toxic effects of heavy metals on 1,2-dichloroethane biodegradation in co-contaminated soil under aerobic condition.

    PubMed

    Olaniran, Ademola Olufolahan; Balgobind, Adhika; Pillay, Balakrishna

    2011-10-01

    1,2-Dichloroethane (1,2-DCA) is one of the most hazardous pollutant of soil and groundwater, and is produced in excess of 5.44×10⁹ kg annually. Owing to their toxicity, persistence and potential for bioaccumulation, there is a growing interest in technologies for their removal. Heavy metals are known to be toxic to soil microorganisms at high concentrations and can hinder the biodegradation of organic contaminants. In this study, the inhibitory effect of heavy metals, namely; arsenic, cadmium, mercury and lead, on the aerobic biodegradation of 1,2-DCA by autochthonous microorganisms was evaluated in soil microcosm setting. The presence of heavy metals was observed to have a negative impact on the biodegradation of 1,2-DCA in both soil samples tested, with the toxic effect being more pronounced in loam soil, than in clay soil. Generally, 75 ppm As³⁺, 840 ppm Hg²⁺, and 420 ppm Pb²⁺ resulted in 34.24%, 40.64%, and 45.94% increase in the half live (t½) of 1,2-DCA, respectively, in loam soil, while concentrations above 127.5 ppm Cd²⁺, 840 ppm Hg²⁺ and 420 ppm of Pb²⁺ and less than 75 ppm As³⁺ was required to cause a >10% increase in the t½ of 1,2-DCA in clay soil. A dose-dependent relationship between degradation rate constant (k₁) of 1,2-DCA and metal ion concentrations was observed for all the heavy metals tested, except for Hg²⁺. This study demonstrated that different heavy metals have different impacts on the degree of 1,2-DCA degradation. Results also suggest that the degree of inhibition is metal specific and is also dependent on several factors including; soil type, pH, moisture content and available nutrients.

  3. Does an aerobic endurance programme have an influence on information processing in migraineurs?

    PubMed Central

    2014-01-01

    Background Migraine is a disorder of central information processing which is characterized by a reduced habituation of event-related potentials. There might be positive effects of aerobic exercise on brain function and pain. The aim of this study was to investigate the influence of exercise on information processing and clinical course of migraine. Methods 33 patients completed a ten-week aerobic exercise programme. To examine the influence of the treatment on information processing and attention, Trail Making Test (TMT) A and B, d2-Letter Cancellation Test (LCT) and recordings of the Contingent Negative Variation (CNV) were performed before and after the training. Results Patients showed a significant reduction of the migraine attack frequency, the iCNV-amplitude and the processing time for TMT-A and TMT-B after treatment. Moreover, there was a significant increase of the habituation and positive changes in parameters of attention (d2-LCT) after the training. Conclusions This study demonstrates that aerobic exercise programme influences central information processing and leads to clinical effects on the migraine symptomatology. The results can be interpreted in terms of an improvement of a dysfunctional information processing and a stimulus selection under aerobic exercise. PMID:24528557

  4. Biodegradation and detoxification of melanoidin from distillery effluent using an aerobic bacterial strain SAG5 of Alcaligenes faecalis.

    PubMed

    Santal, Anita Rani; Singh, N P; Saharan, Baljeet Singh

    2011-10-15

    Distillery effluent retains very dark brown color even after anaerobic treatment due to presence of various water soluble, recalcitrant and coloring compounds mainly melanoidins. In laboratory conditions, melanoidin decolorizing bacteria was isolated and optimized the cultural conditions at various incubation temperatures, pH, carbon sources, nitrogen sources and combined effect of both carbon and nitrogen sources. The optimum decolorization (72.6 ± 0.56%) of melanoidins was achieved at pH 7.5 and temperature 37 °C on 5th day of cultivation. The toxicity evaluation with mung bean (Vigna radiata) revealed that the raw distillery effluent was environmentally highly toxic as compared to biologically treated distillery effluent, which indicated that the effluent after bacterial treatment is environmentally safe. This proves to be novel biological treatment technique for biodegradation and detoxification of melanoidin from distillery effluent using the bacterial strain SAG(5).

  5. Aerobic co-treatment of landfill leachate and domestic wastewater - are slowly biodegradable organics removed or simply diluted?

    PubMed

    Campos, R; Ferraz, F M; Vieira, E M; Povinelli, J

    2014-01-01

    This study investigated the co-treatment of landfill leachate/domestic wastewater in bench-scale activated sludge (AS) reactors to determine whether the slowly biodegradable organic matter (SBOM) was removed rather than diluted. The AS reactors were loaded with mixtures of raw leachate and leachate that was pretreated by air stripping. The tested volumetric ratios were 0%, 0.2%, 2% and 5%. For all of the tested conditions, the reactors performed better when pretreated leachate was used rather than raw leachate, and the best volumetric ratio was 2%. The following removals were obtained: 97% for the biochemical oxygen demand (BOD5,20), 79% for total suspended solids, 77% for dissolved organic carbon and 84% for soluble chemical oxygen demand. Most of the pretreated leachate SBOM (65%) was removed rather than diluted or adsorbed into the sludge, as confirmed by Fourier transform infrared (FTIR) spectroscopy analyses.

  6. Investigation of the use of aerobic granules for the treatment of sugar beet processing wastewater.

    PubMed

    Kocaturk, Irem; Erguder, Tuba Hande

    2015-01-01

    The treatment of sugar beet processing wastewater in aerobic granular sequencing batch reactor (SBR) was examined in terms of chemical oxygen demand (COD) and nitrogen removal efficiency. The effect of sugar beet processing wastewater of high solid content, namely 2255 ± 250 mg/L total suspended solids (TSS), on granular sludge was also investigated. Aerobic granular SBR initially operated with the effluent of anaerobic digester treating sugar beet processing wastewater (Part I) achieved average removal efficiencies of 71 ± 30% total COD (tCOD), 90 ± 3% total ammonifiable nitrogen (TAN), 76 ± 24% soluble COD (sCOD) and 29 ± 4% of TSS. SBR was further operated with sugar beet processing wastewater (Part II), where the tCOD, TAN, sCOD and TSS removal efficiencies were 65 ± 5%, 61 ± 4%, 87 ± 1% and 58 ± 10%, respectively. This study indicated the applicability of aerobic granular SBRs for the treatment of both sugar beet processing wastewater and anaerobically digested processing wastewater. For higher solids removal, further treatment such as a sedimentation tank is required following the aerobic granular systems treating solid-rich wastewaters such as sugar beet processing wastewater. It was also revealed that the application of raw sugar beet processing wastewater slightly changed the aerobic granular sludge properties such as size, structure, colour, settleability and extracellular polymeric substance content, without any drastic and negative effect on treatment performance.

  7. Stochastic-convective transport with nonlinear reaction and mixing: application to intermediate-scale experiments in aerobic biodegradation in saturated porous media.

    PubMed

    Ginn, T R; Murphy, E M; Chilakapati, A; Seeboonruang, U

    2001-03-01

    Aerobic biodegradation of benzoate by Pseudomonas cepacia sp. in a saturated heterogeneous porous medium was simulated using the stochastic-convective reaction (SCR) approach. A laboratory flow cell was randomly packed with low permeability silt-size inclusions in a high permeability sand matrix. In the SCR upscaling approach, the characteristics of the flow field are determined by the breakthrough of a conservative tracer. Spatial information on the actual location of the heterogeneities is not used. The mass balance equations governing the nonlinear and multicomponent reactive transport are recast in terms of reactive transports in each of a finite number of discrete streamtubes. The streamtube ensemble members represent transport via a steady constant average velocity per streamtube and a conventional Fickian dispersion term, and their contributions to the observed breakthroughs are determined by flux-averaging the streamtube solute concentrations. The resulting simulations were compared to those from a high-resolution deterministic simulation of the reactive transport, and to alternative ensemble representations involving (i) effective Fickian travel time distribution function, (ii) purely convective streamtube transport, and (iii) streamtube ensemble subset simulations. The results of the SCR simulation compare favorably to that of a sophisticated high-resolution deterministic approach.

  8. Stochastic-convective transport with nonlinear reaction and mixing: application to intermediate-scale experiments in aerobic biodegradation in saturated porous media

    NASA Astrophysics Data System (ADS)

    Ginn, T. R.; Murphy, E. M.; Chilakapati, A.; Seeboonruang, U.

    2001-03-01

    Aerobic biodegradation of benzoate by Pseudomonas cepacia sp. in a saturated heterogeneous porous medium was simulated using the stochastic-convective reaction (SCR) approach. A laboratory flow cell was randomly packed with low permeability silt-size inclusions in a high permeability sand matrix. In the SCR upscaling approach, the characteristics of the flow field are determined by the breakthrough of a conservative tracer. Spatial information on the actual location of the heterogeneities is not used. The mass balance equations governing the nonlinear and multicomponent reactive transport are recast in terms of reactive transports in each of a finite number of discrete streamtubes. The streamtube ensemble members represent transport via a steady constant average velocity per streamtube and a conventional Fickian dispersion term, and their contributions to the observed breakthroughs are determined by flux-averaging the streamtube solute concentrations. The resulting simulations were compared to those from a high-resolution deterministic simulation of the reactive transport, and to alternative ensemble representations involving (i) effective Fickian travel time distribution function, (ii) purely convective streamtube transport, and (iii) streamtube ensemble subset simulations. The results of the SCR simulation compare favorably to that of a sophisticated high-resolution deterministic approach.

  9. Process for separating and/or recovering hydrocarbon oils from water using biodegradable absorbent sponges

    SciTech Connect

    Mueller, M.B.; Mareau, K.J.

    1991-08-13

    This patent describes an improved process for absorbing oils selected from the group consisting of hydrocarbon oils and hydrocarbon fuels. It comprises the step of contacting the oils with an absorbent oleophilic biodegradable sponge material comprised of at least one essentially fat free, foamed, biodegradable natural product selected from the group consisting of animal proteins and plant polymaccharides, which material is capable of absorbing at least about thirty times its weight of oils.

  10. Predicting biodegradable volatile solids degradation profiles in the composting process.

    PubMed

    Mason, I G

    2009-02-01

    This paper presents a new method for the prediction of the pattern of biodegradable volatile solids (BVS) degradation in the composting process. The procedure is based on a re-arrangement of the heat balance around a composting system to numerically solve for the rate of BVS carbon (BVS-C) disappearance. Input data for the model was obtained from composting experiments conducted in a laboratory-scale, constant temperature difference (CTD) reactor simulating a section of an aerated static pile, and using a simulated feedstock comprising ostrich feed, shredded paper, finished compost and woodchips. These experiments also provided validation data in the form of exit gas CO(2) carbon (CO(2)-C) profiles. The model successfully predicted the generic shape of experimental substrate degradation profiles obtained from CO(2) measurements, but under the conditions and assumptions of the experiment, the profiles were quantitatively different, giving an over-estimate of BVS-C. Both measured CO(2)-C and predicted BVS-C profiles were moderately to well fitted by a single exponential function, with replicated rate coefficient values of 0.08 and 0.09 d(-1), and 0.06 and 0.07 d(-1), respectively. In order to explore the underlying shape of the profiles, measured and predicted data at varying temperature were corrected to a constant temperature of 40 degrees C, using the temperature correction function of Rosso et al. [Rosso, L., Lobry, J.R., and Flandrois, J.P., 1993. An unexpected correlation between cardinal temperatures of microbial growth highlighted by a new model. Journal of Theoretical Biology, 162, 447-463], with cardinal temperatures of 5, 59 and 85 degrees C. Multi-phase profiles were generated for both the measured CO(2)-C and the predicted BVS-C data in this case. However, when alternative cardinal temperatures of 5, 55 and 80 degrees C, or 5, 50 and 80 degrees C, were used, the predicted profiles assumed an exponential shape, and excellent fits were obtained using a

  11. Bacterial interactions and implications for oil biodegradation process in mangrove sediments.

    PubMed

    Grativol, Adriana Daudt; Marchetti, Albany A; Wetler-Tonini, Rita M; Venancio, Thiago M; Gatts, Carlos En; Thompson, Fabiano L; Rezende, Carlos E

    2017-03-01

    Mangrove sediment harbors a unique microbiome and is a hospitable environment for a diverse group of bacteria capable of oil biodegradation. Our goal was to understand bacterial community dynamics from mangrove sediments contaminated with heavy-oil and to evaluate patterns potentially associated with oil biodegradation is such environments. We tested the previously proposed hypothesis of a two-phase pattern of petroleum biodegradation, under which key events in the degradation process take place in the first three weeks after contamination. Two sample sites with different oil pollution histories were compared through T-RFLP analyses and using a pragmatic approach based on the Microbial Resource Management Framework. Our data corroborated the already reported two-phase pattern of oil biodegradation, although the original proposed explanation related to the biophysical properties of the soil is questioned, opening the possibility to consider other plausible hypotheses of microbial interactions as the main drivers of this pattern.

  12. Solid recovered fuel production from biodegradable waste in grain processing industry.

    PubMed

    Kliopova, Irina; Staniskis, Jurgis Kazimieras; Petraskiene, Violeta

    2013-04-01

    Management of biodegradable waste is one of the most important environmental problems in the grain-processing industry since this waste cannot be dumped anymore due to legal requirements. Biodegradable waste is generated in each stage of grain processing, including the waste-water and air emissions treatment processes. Their management causes some environmental and financial problems. The majority of Lithuanian grain-processing enterprises own and operate composting sites, but in Lithuania the demand for compost is not given. This study focused on the analysis of the possibility of using biodegradable waste for the production of solid recovered fuel, as a local renewable fuel with the purpose of increasing environmental performance and decreasing the direct costs of grain processing. Experimental research with regard to a pilot grain-processing plant has proven that alternative fuel production will lead to minimizing of the volume of biodegradable waste by 75% and the volume of natural gas for heat energy production by 62%. Environmental indicators of grain processing, laboratory analysis of the chemical and physical characteristics of biodegradable waste, mass and energy balances of the solid recovered fuel production, environmental and economical benefits of the project are presented and discussed herein.

  13. An anoxic-aerobic system for simultaneous biodegradation of phenol and ammonia in a sequencing batch reactor.

    PubMed

    Liu, Qifeng; Singh, Vijay P; Fu, Zhimin; Wang, Jing; Hu, La

    2017-03-24

    A laboratory-scale sequencing batch reactor (SBR) was investigated to treat artificial pretreated coal gasification wastewater that was mainly contained of ammonia and phenol. The efficiency of SBR fed with increasing phenol concentrations (from 150 to 300 mg l(-1)) and the relationship among phenol, nitrogen removal, and the microbial community structure were evaluated. When the phenol feeding concentration was increased to about 300 mg l(-1), the removal efficiency was above 99.0%, demonstrating the robustness of phenol removal capacity. The study showed that most phenol was degraded in anoxic stage. The average removal efficiencies of ammonia and total nitrogen were 98.4 and 81.9%, respectively, with average NH4(+)-N concentration of 107.5 mg l(-1) and COD/N 7.5. Low temperature caused sludge loss that led to the decreased performance. Increasing the temperature could not recover the performance effectively. The data from bacterial analysis revealed that Delftia, Hydrogenophaga, and unclassified Xanthomonadaceae played a significant role in phenol degradation before the temperature increase, while uncultured Syntrophococcus sp. and unclassified Rhodocyclaceae were responsible for phenol degradation after the temperature increase. These results imply that the SBR holds potential for the simultaneous removal of phenolic compounds and nitrogen through aerobic ammonia oxidation and anoxic denitrification with phenol as the co-organic carbon source.

  14. Systems Characterization of Temperature, Ph and Electrical Conductivity in Aerobic Biodegradation of Wheat Biomass at Differing Mixing Rates

    NASA Technical Reports Server (NTRS)

    Calhoun, M.; Trotman, A.; Aglan, H.

    1998-01-01

    The purpose of this preliminary study is to observe and relate the rate of mixing to pH and electrical conductivity in an aerobic, continuously stirred bioreactor. The objective is to use data collected from successive experiments as a means of a system characterization. Tests were conducted to obtain these data using a continuously stirred 20 L Cytostir glass reaction vessel as a bioreactor operated without built-in temperature or pH control. The tests were conducted on the lab bench at ambient temperatures. The substrate in the bioreactor was ground wheat biomass obtained from the Biomass Production Chamber at NASA Kennedy Space Center. In this study, the data reflect characteristics of the native (uninoculated) systems as well as inoculated systems. In the native systems, it was found that pi levels became stable after approximately 2 to 3 days. The electrical conductivity levels for the native systems tended to decrease over time. In contrast, ion activity was increased after the introduction of bacteria into the system. This could be correlated with the release of nutrients, due to the activity of the bacteria. Also, there were slight increases in pH in the inoculated system, a result which is expected for a system with no active pr controls. The data will be used to test a mathematical model in an automated system.

  15. Biodegradation of tetramethylammonium hydroxide (TMAH) in completely autotrophic nitrogen removal over nitrite (CANON) process.

    PubMed

    Chen, Shen-Yi; Lu, Li-An; Lin, Jih-Gaw

    2016-06-01

    This study conducted a completely autotrophic nitrogen removal over nitrite (CANON) process in a continuous anoxic upflow bioreactor to treat synthetic wastewater with TMAH (tetramethylammonium hydroxide) ranging from 200 to 1000mg/L. The intermediates were analyzed for understanding the metabolic pathway of TMAH biodegradation in CANON process. In addition, (15)N-labeled TMAH was used as the substrate in a batch anoxic bioreactor to confirm that TMAH was converted to nitrogen gas in CANON process. The results indicated that TMAH was almost completely biodegraded in CANON system at different influent TMAH concentrations of 200, 500, and 1000mg/L. The average removal efficiencies of total nitrogen were higher than 90% during the experiments. Trimethylamine (TMA) and methylamine (MA) were found to be the main biodegradation intermediates of TMAH in CANON process. The production of nitrogen gas with (15)N-labeled during the batch anaerobic bioreactor indicated that CANON process successfully converted TMAH into nitrogen gas.

  16. Two-stage anaerobic and post-aerobic mesophilic digestion of sewage sludge: Analysis of process performance and hygienization potential.

    PubMed

    Tomei, M Concetta; Mosca Angelucci, Domenica; Levantesi, Caterina

    2016-03-01

    Sequential anaerobic-aerobic digestion has been demonstrated to be effective for enhanced sludge stabilization, in terms of increased solid reduction and improvement of sludge dewaterability. In this study, we propose a modified version of the sequential anaerobic-aerobic digestion process by operating the aerobic step under mesophilic conditions (T=37 °C), in order to improve the aerobic degradation kinetics of soluble and particulate chemical oxygen demand (COD). Process performance has been assessed in terms of "classical parameters" such as volatile solids (VS) removal, biogas production, COD removal, nitrogen species, and polysaccharide and protein fate. The aerobic step was operated under intermittent aeration to achieve nitrogen removal. Aerobic mesophilic conditions consistently increased VS removal, providing 32% additional removal vs. 20% at 20 °C. Similar results were obtained for nitrogen removal, increasing from 64% up to 99% at the higher temperature. Improved sludge dewaterability was also observed with a capillary suction time decrease of ~50% during the mesophilic aerobic step. This finding may be attributable to the decreased protein content in the aerobic digested sludge. The post-aerobic digestion exerted a positive effect on the reduction of microbial indicators while no consistent improvement of hygienization related to the increased temperature was observed. The techno-economic analysis of the proposed digestion layout showed a net cost saving for sludge disposal estimated in the range of 28-35% in comparison to the single-phase anaerobic digestion.

  17. Microbiology of the frankfurter process: salmonella and natural aerobic flora.

    PubMed

    Palumbo, S A; Huhtanen, C N; Smith, J L

    1974-04-01

    Salmonella senftenberg 775W added to frankfurter emulsion was killed during normal processing in the smoke house when internal product temperature was 71.1 C (160 F) or above. The thermal destruction point of S. senftenberg 775W in frankfurters (temperature at which no viable cells were detected) was a function of the length of time of the process rather than of the starting number of cells. Heating of frankfurters to 73.9 C (165 F) substantially reduced the total non-salmonella count. For total non-salmonella bacterial flora and salmonella, relatively little thermal destruction occurred below 43.3 C (110 F). The heating step can bring about a 7-log cycle decrease (10(8) to 10(1)/g) of bacteria present in the raw emulsion. The flora of this high-bacteriological-count raw emulsion was predominantly gram-negative rods. Variation in the number of bacteria (both total and salmonella) surviving at various temperatures during processing was attributed to slight variations in the temperature pattern of the smoke house during its operation. An integration process was devised which allowed calculation of exposure to temperatures above 110 F (43.3 C) on the basis of degree-minutes. Plots of degree-minutes versus log of surviving bacteria were linear. The salmonella plot had a greater slope than that of the total non-salmonella flora, indicating that salmonellae are more heat sensitive than the bacterial population as a whole. The predominant bacteria surviving the heating step were micrococci. These micrococci were able to increase in number in or on the frankfurters during storage at 5 C.

  18. Comparison of biodegradation of low-weight hydroentangled raw cotton nonwoven fabric and that of commonly used disposable nonwoven fabrics in the aerobic Captina silt loam soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increasing use of disposable nonwovens made of petroleum-based materials generates a large amount of non-biodegradable, solid waste in the environment. As an effort to enhance the usage of biodegradable cotton in nonwovens, this study analyzed the biodegradability of mechanically pre-cleaned gr...

  19. Evaluation and Optimization of MTBE Biodegradation in Aquifers, Final Report

    SciTech Connect

    Legler, T; Balser, L; Koester, C; Wilson, W

    2004-02-13

    This study was focused on meeting the following objectives concerning the process of methyl tertiary butyl ether (MTBE) biodegradation, with the goal of optimizing this process in situ: 1. Assess whether intrinsic bioattenuation of MTBE is feasible under aerobic conditions across several contaminated sites. 2. Determine the effect of co-contaminants, specifically water-soluble gasoline components (most notably benzene, toluene, ethylbenzene and xylenes [BTEX]) on MTBE biodegradation. 3. Determine whether microbial and/or chemical factors contribute to different MTBE degradative activities. 4. Isolate and characterize MTBE-degrading microorganisms from sediments in which MTBE biodegradation was observed.

  20. Biological treatment of high-pH and high-concentration black liquor of cotton pulp by an immediate aerobic-anaerobic-aerobic process.

    PubMed

    Lihong, Miao; Furong, Li; Jinli, Wen

    2009-01-01

    In this study, an immediate aerobic-anaerobic-aerobic (O/A/O) biological process was established for the treatment of black liquor of cotton pulp and was tested by both laboratory-scale batch experiment and pilot-scale continuous experiment. The effects of the hydraulic retention time (HRT) were studied, as were the alkaliphilic bacteria number, the culturing temperature and the concentration of black liquor on COD (chemical oxygen demand) removal. The total COD (COD(tot)) removal rate of the novel O/A/O process, for a black liquor with influent COD(tot) over 8,000 mg/L and pH above 12.8, was 68.7+/-4% which is similar with that of the traditional acidic-anaerobic-aerobic process (64.9+/-3%). The first aerobic stage based on alkaliphilic bacteria was the crucial part of the process, which was responsible for decreasing the influent pH from above 12 to an acceptable level for the following treatment unit. The average generation time of the alkaliphilic bacteria in the black liquor was about 36 minutes at 40 degrees C in a batch aerobic activated sludge system. The efficiency of the first aerobic stage was affected greatly by the temperature. The COD(tot) removal at 55 degrees C was much lower in comparison with the COD(tot) removal at 45 degrees C or 50 degrees C. Both the laboratory-scale batch experiments and the pilot-scale continuous experiment showed that the COD(tot) removal rate could reach about 65% for original black liquor with a pH of about 13.0 and a COD of 18,000-22,000 mg/L by the immediate O/A/O process. The first aerobic stage gave an average COD(tot) removal of 45.5% at 35 degrees C (HRT = 72 h) at a volume loading rate of 3.4 kg COD m(-3) d(-1).

  1. Biodegradability enhancement of a leachate after biological lagooning using a solar driven photo-Fenton reaction, and further combination with an activated sludge biological process, at pre-industrial scale.

    PubMed

    Silva, Tânia F C V; Fonseca, Amélia; Saraiva, Isabel; Vilar, Vítor J P; Boaventura, Rui A R

    2013-06-15

    This work proposes an integrated leachate treatment strategy, combining a solar photo-Fenton reaction, to enhance the biodegradability of the leachate from an aerated lagoon, with an activated sludge process, under aerobic and anoxic conditions, to achieve COD target values and nitrogen content according to the legislation. The efficiency and performance of the photo-Fenton reaction, concerning a sludge removal step after acidification, defining the optimum phototreatment time to reach a biodegradable wastewater that can be further oxidized in a biological reactor and, activation sludge biological process, defining the nitrification and denitrification reaction rates, alkalinity balance and methanol dose necessary as external carbon source, was evaluated in the integrated system at a scale close to industrial. The pre-industrial plant presents a photocatalytic system with 39.52 m(2) of compound parabolic collectors (CPCs) and 2 m(3) recirculation tank and, an activated sludge biological reactor with 3 m(3) capacity. Leachate biodegradability enhancement by means of a solar driven photo-Fenton process was evaluated using direct biodegradability tests, as Zahn-Wellens method, and indirect measure according to average oxidation state (AOS), low molecular carboxylic acids content (fast biodegradable character) and humic substances (recalcitrant character) concentration. Due to high variability of leachate composition, UV absorbance on-line measurement was established as a useful parameter for photo-Fenton reaction control.

  2. Trace metal pyritization variability in response to mangrove soil aerobic and anaerobic oxidation processes.

    PubMed

    Machado, W; Borrelli, N L; Ferreira, T O; Marques, A G B; Osterrieth, M; Guizan, C

    2014-02-15

    The degree of iron pyritization (DOP) and degree of trace metal pyritization (DTMP) were evaluated in mangrove soil profiles from an estuarine area located in Rio de Janeiro (SE Brazil). The soil pH was negatively correlated with redox potential (Eh) and positively correlated with DOP and DTMP of some elements (Mn, Cu and Pb), suggesting that pyrite oxidation generated acidity and can affect the importance of pyrite as a trace metal-binding phase, mainly in response to spatial variability in tidal flooding. Besides these aerobic oxidation effects, results from a sequential extraction analyses of reactive phases evidenced that Mn oxidized phase consumption in reaction with pyrite can be also important to determine the pyritization of trace elements. Cumulative effects of these aerobic and anaerobic oxidation processes were evidenced as factors affecting the capacity of mangrove soils to act as a sink for trace metals through pyritization processes.

  3. Grey water biodegradability.

    PubMed

    Ghunmi, Lina Abu; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

    2011-02-01

    Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively.

  4. Two-dimensional flow-through microcosms - Versatile test systems to study biodegradation processes in porous aquifers

    NASA Astrophysics Data System (ADS)

    Bauer, Robert D.; Rolle, Massimo; Kürzinger, Petra; Grathwohl, Peter; Meckenstock, Rainer U.; Griebler, Christian

    2009-05-01

    SummaryA fundamental prerequisite of any remedial activity is a sound knowledge of both the biotic and abiotic processes involved in transport and degradation of contaminants. Investigations of these aspects in situ often seem infeasible due to the complexity of interacting processes. A simplified portrayal of nature can be facilitated in laboratory-based two-dimensional (2D) sediment flow-through microcosms. This paper describes the versatility of such simple aquifer model systems with respect to biodegradation of aromatic hydrocarbons, i.e. toluene and ethylbenzene, under various environmental conditions. Initially constructed to study non-reactive and bioreactive transport of organic contaminants in homogeneous porous media under steady state hydraulic conditions, experimental setups developed towards more realistic heterogeneous sediment packing and transient hydraulic conditions. High-resolution spatial and temporal sampling allowed to obtain new insights on the distribution of bioactivities in contaminant plumes and associated controlling and limiting factors. Major biodegradation activities in saturated porous sediments are located at the fringes of contaminant plumes and are driven by dispersive mixing. These hot-spots of contaminant biotransformation are characterized by steep physical-chemical gradients in the millimeter to centimeter range. Sediment heterogeneity, i.e. high-conductivity zones, was shown to significantly enhance transverse mixing and subsequently biodegradation. On the contrary, transient hydraulic conditions may generate intermediate disturbances to biodegrader populations and thus may interfere with optimized contaminant conversion. However, a bacterial strain aerobically degrading toluene, i.e. Pseudomonas putida F1, was shown to adapt to vertically moving contaminant plumes, in the way that it regained full biodegradation potential two-times faster in areas with a mid-term (days to weeks) contamination history than in areas not

  5. Treatment of leather industry wastewater by aerobic biological and Fenton oxidation process.

    PubMed

    Mandal, Tamal; Dasgupta, Dalia; Mandal, Subhasis; Datta, Siddhartha

    2010-08-15

    Degradation of leather industry wastewater by sole aerobic treatment incorporating Thiobacillus ferrooxidans, Fenton's reagents, and combined treatment was investigated in this study. The sole treatment by Fenton's oxidation involving the introduction of 6g FeSO(4) and 266 g H(2)O(2) in a liter of wastewater at pH of 3.5 and 30 degrees C for 30 min at batch conditions reduced COD, BOD(5), sulfide, total chromium and color up to 69%, 72%, 88%, 5%, 100% and T. ferrooxidans alone showed maximum reduction to an extent of 77, 80, 85, 52, 89, respectively, in 21 d treatment at pH 2.5, FeSO(4) 16 g/L and temperature of 30 degrees C. The combined treatment at batch conditions involving 30 min chemical treatment by Fenton's oxidation followed by 72 h biochemical treatment by T. ferrooxidans at batch conditions gave rise up to 93%, 98%, 72%, 62% and 100% removal efficiencies of COD, BOD, sulfide, chromium and color at pH of 2.5 and 30 degrees C. Decrease in photo absorption of the Fenton's reagent treated samples, as compared to the banks, at 280, 350 and 470 nm wave lengths was observed. This may be the key factor for stimulating the biodegradation by T. ferrooxidans.

  6. Monitoring operational and leachate characteristics of an aerobic simulated landfill bioreactor.

    PubMed

    Giannis, A; Makripodis, G; Simantiraki, F; Somara, M; Gidarakos, E

    2008-01-01

    Long-term biodegradation of MSW in an aerobic landfill bioreactor was monitored as a function of time during 510 days of operation. Operational characteristics such as air importation, temperature and leachate recirculation were monitored. The oxygen utilization rates and biodegradation of organic matter rates showed that aerobic biodegradation was feasible and appropriate to proceed in aerobic landfill bioreactor. Leachate analyses showed that the aerobic bioreactor could remove above 90% of chemical oxygen demand (COD) and close to 100% of biochemical oxygen demand (BOD5) from leachate. Ammonium (NH4+), nitrate (NO3-) and sulphate (SO4(2-)) concentrations of leachate samples were regularly measured. Results suggest that nitrification and denitrification occurred simultaneously, and the increase in nitrate did not reach the levels predicted stoichiometrically, suggesting that other processes were occurring. Leachate recirculation reduced the concentrations of heavy metals because of the effect of the high pH of the leachate, causing heavy metals to be retained by processes such as sorption on MSW, carbonate precipitation, and hydroxide precipitation. Furthermore, the compost derived from the aerobic biodegradation of the organic matter of MSW may be considered as soil improvement in the agricultural plant production. Bio-essays indicated that the ecotoxicity of leachate from the aerobic bioreactor was not toxic at the end of the experiment. Finally, after 510 days of degradation, waste settlement reached 26% mainly due to the compost of the organic matter.

  7. Biodegradability of chlorophenol wastewater enhanced by solar photo-Fenton process.

    PubMed

    Kuo, W S; Lin, I T

    2009-01-01

    The combination of solar irradiation and Fenton reagent have been used to enhance the biodegradability (BOD(5)/COD) of chlorophenol wastewater, including 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), and 2,4-dichlorophenol (2,4-DCP). Results showed that the solar photo-Fenton process improved significantly the biodegradability of chlorophenol wastewater. Basically, increasing initial H(2)O(2) dosage was much more beneficial for increasing biodegradability of wastewater than increasing initial Fe(2 + ) dosage. Among the conditions studied, the optimum condition of increasing biodegradability of chlorophenol wastewater was found with a [H(2)O(2)](0)/[Fe(2 + )](0)/[chlorophenol](0) ratio of 10.0/0.2/1.0, 10.0/0.3/1.0, and 10.0/0.2/1.0 for 2-CP, 4-CP, and 2,4-DCP, respectively. As a result, the value of BOD(5)/COD was increased from 0 for untreated solution up to 0.231, 0.248, and 0.193 for 2-CP, 4-CP, and 2,4-DCP, respectively with a 15-min treatment. Under the operation of optimum conditions, the oxidative state of chlorophenol wastewater could be easily controlled into a higher biodegradability stage. The COD and TOC degradation efficiency could be in excess of 90% on the whole as the preoxidized chlorophenol solution was treated by a following batch-type biological unit. In the meanwhile, the microtoxicity of wastewater reduced more than 95%.

  8. [Start-up and operation characteristics of aerobic granular short-cut nitrification process].

    PubMed

    Yang, Yang; Zuo, Jian-E; Bu, De-Hua; Gu, Xia-Sheng

    2007-11-01

    In a lab-scale aerated upflow sludge bed (AUSB) reactor inoculated with the mixture of anaerobic granular sludge and aerobic sludge, using synthetic ammonia-rich wastewater as influent, aerobic short-cut nitrification granules were cultivated. After that, the short-cut nitrification reactor could be operated stably with very high efficiency under mesophilic condition (30 approximately 35 degrees C), and the influent loading rate (NH4(+) -N) could reach 2.5 approximately 3.0 kg/(m3 x d). The ammonia removal efficiency and the short-cut nitrification ratio (NO2(-)/NOx(-)) were above 90% respectively. Some organic COD (about 100 mg/L) existed in the influent had no obvious effects on the operation of the short-cut nitrification process. The short-cut nitrification reactor could also be operated stably with very high efficiency under ambient temperature (about 20 degrees C).

  9. Sorption and biodegradation of artificial sweeteners in activated sludge processes.

    PubMed

    Tran, Ngoc Han; Gan, Jie; Nguyen, Viet Tung; Chen, Huiting; You, Luhua; Duarah, Ankur; Zhang, Lifeng; Gin, Karina Yew-Hoong

    2015-12-01

    There is limited information on the occurrence and removal of artificial sweeteners (ASs) in biological wastewater treatment plants, and in particular, the contribution of sorption and biodegradation to their removal. This study investigated the fate of ASs in both the aqueous and solid phases in a water reclamation plant (WRP). All the four targeted ASs, i.e. acesulfame (ACE), sucralose (SUC), cyclamate (CYC) and saccharine (SAC), were detected in both the aqueous and solid phases of raw influent and primary effluent samples. The concentrations of CYC and SAC in secondary effluent or MBR permeate were below their method detection limits. ACE and SUC were persistent throughout the WRP, whereas CYC and SAC were completely removed in biological treatment (>99%). Experimental results showed that sorption played a minor role in the elimination of the ASs due to the relatively low sorption coefficients (Kd), where Kd<500L/kg. In particular, the poor removal of ACE and SUC in the WRP may be attributed to their physiochemical properties (i.e. logKow<0 or logD<3.2) and chemical structures containing strong withdrawing electron functional groups in heterocyclic rings (i.e. chloride and sulfonate).

  10. Aerobic Exercise Training in Post-Polio Syndrome: Process Evaluation of a Randomized Controlled Trial

    PubMed Central

    Voorn, Eric L.; Koopman, Fieke S.; Brehm, Merel A.; Beelen, Anita; de Haan, Arnold; Gerrits, Karin H. L.; Nollet, Frans

    2016-01-01

    Objective To explore reasons for the lack of efficacy of a high intensity aerobic exercise program in post-polio syndrome (PPS) on cardiorespiratory fitness by evaluating adherence to the training program and effects on muscle function. Design A process evaluation using data from an RCT. Patients Forty-four severely fatigued individuals with PPS were randomized to exercise therapy (n = 22) or usual care (n = 22). Methods Participants in the exercise group were instructed to exercise 3 times weekly for 4 months on a bicycle ergometer (60–70% heart rate reserve). Results The attendance rate was high (median 89%). None of the participants trained within the target heart rate range during >75% of the designated time. Instead, participants exercised at lower intensities, though still around the anaerobic threshold (AT) most of the time. Muscle function did not improve in the exercise group. Conclusion Our results suggest that severely fatigued individuals with PPS cannot adhere to a high intensity aerobic exercise program on a cycle ergometer. Despite exercise intensities around the AT, lower extremity muscle function nor cardiorespiratory fitness improved. Improving the aerobic capacity in PPS is difficult through exercise primarily focusing on the lower extremities, and may require a more individualized approach, including the use of other large muscle groups instead. Trial Registration Netherlands National Trial Register NTR1371 PMID:27419388

  11. Aerobic biodegradation of Azo dye by Bacillus cohnii MTCC 3616; an obligately alkaliphilic bacterium and toxicity evaluation of metabolites by different bioassay systems.

    PubMed

    Prasad, A S Arun; Rao, K V Bhaskara

    2013-08-01

    An obligate alkaliphilic bacterium Bacillus cohnii MTCC 3616 aerobically decolorized a textile azo dye Direct Red-22 (5,000 mg l⁻¹) with 95 % efficiency at 37 °C and pH 9 in 4 h under static conditions. The decolorization of Direct Red-22 (DR-22) was possible through a broad pH (7-11), temperature (10-45 °C), salinity (1-7 %), and dye concentration (5-10 g l⁻¹) range. Decolorization of dye was assessed by UV-vis spectrophotometer with reduction of peak intensity at 549 nm (λ(max)). Biodegradation of dye was analyzed by Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). The FTIR spectrum revealed that B. cohnii specifically targeted azo bond (N=N) at 1,614.42 cm⁻¹ to break down Direct Red-22. Formation of metabolites with different retention times in HPLC analysis further confirmed the degradation of dye. The phytotoxicity test with 5,000 mg l⁻¹ of untreated dye showed 80 % germination inhibition in Vigna mungo, 70 % in Sorghum bicolor and 80 % in Vigna radiata. No germination inhibition was noticed in all three plants by DR-22 metabolites at 5,000 mg l⁻¹. Biotoxicity test with Artemia salina proved the lethality of the azo dye at LC₅₀ of 4 and 8 % for degraded metabolites by causing death of its nauplii compared to its less toxic-degraded metabolites. Bioaccumulation of dye was observed in the mid-gut of A. salina. The cytogenotoxicity assay on the meristematic root tip cells of Allium cepa further confirmed the cytotoxic nature of azo dye (DR-22) with decrease in mitotic index (0.5 % at 500 ppm) and increase in aberrant index (4.56 %) over 4-h exposure period. Genotoxic damages (lagging chromosome, metaphase cluster, chromosome bridges, and dye accumulation in cytoplasm) were noticed at different stages of cell cycle. The degraded metabolites had negligible cytotoxic and genotoxic effects.

  12. SITE TECHNOLOGY CAPSULE: ZENOGEM™ WASTEWATER TREATMENT PROCESS

    EPA Science Inventory

    Zenon Environmental System's ZenoGem™ Wastewater Treatment Process treats aqueous media contaminated with volatile/semi-volatile organic compounds. This technology combines aerobic biological treatment to remove biodegradable organic compounds with ultrafiltration to separate res...

  13. Comparative evaluation of cyanide removal by adsorption, biodegradation, and simultaneous adsorption and biodegradation (SAB) process using Bacillus cereus and almond shell.

    PubMed

    Dwivedi, Naveen; Balomajumder, Chandrajit; Mondal, Prasenji

    2016-07-01

    The present study aimed to investigate the removal efficiency of cyanide from contaminated water by adsorption, biodegradation and simultaneous adsorption and biodegradation (SAB) process individually in a batch reactor. Adsorption was achieved by using almond shell granules and biodegradation was conducted with suspended cultures of Bacillus cereus, whereas SAB process was carried out using Bacillus cereus and almond shell in a batch reactor. The effect of agitation time, pH, and initial cyanide concentration on the % removal of cyanide has been discussed. Under experimental conditions, optimum removal was obtained at pH 7 with agitation time of 48 hrs and temperature of 35 degrees C. Cyanide was utilized by bacteria as sole source of nitrogen for growth. The removal efficiencies of cyanide by adsorption, biodegradation, and SAB were found to be 91.38%, 95.87%, and 99.63%, respectively, at initial cyanide concentration of 100 mg l(-1). The removal efficiency of SAB was found to be better as compared to that of biodegradation and adsorption alone.

  14. Evaluation of integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor for decolorization and biodegradation of azo dye acid red 18: comparison of using two types of packing media.

    PubMed

    Hosseini Koupaie, E; Alavi Moghaddam, M R; Hashemi, S H

    2013-01-01

    Two integrated anaerobic/aerobic fixed-bed sequencing batch biofilm reactor (FB-SBBR) were operated to evaluate decolorization and biodegradation of azo dye Acid Red 18 (AR18). Volcanic pumice stones and a type of plastic media made of polyethylene were used as packing media in FB-SBBR1 and FB-SBBR2, respectively. Decolorization of AR18 in both reactors followed first-order kinetic with respect to dye concentration. More than 63.7% and 71.3% of anaerobically formed 1-naphthylamine-4-sulfonate (1N-4S), as one of the main sulfonated aromatic constituents of AR18 was removed during the aerobic reaction phase in FB-SBBR1 and FB-SBBR2, respectively. Based on statistical analysis, performance of FB-SBBR2 in terms of COD removal as well as biodegradation of 1N-4S was significantly higher than that of FB-SBBR1. Spherical and rod shaped bacteria were the dominant species of bacteria in the biofilm grown on the pumice stones surfaces, while, the biofilm grown on surfaces of the polyethylene media had a fluffy structure.

  15. Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

    PubMed

    Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

    2015-05-15

    Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 < EF < PEF ≤ SPEF. The SPEF process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total

  16. Studies in reactive extrusion processing of biodegradable polymeric materials

    NASA Astrophysics Data System (ADS)

    Balakrishnan, Sunder

    Various reaction chemistries such as Polymerization, Polymer cross-linking and Reactive grafting were investigated in twin-screw extruders. Poly (1,4-dioxan-2-one) (PPDX) was manufactured in melt by the continuous polymerization of 1,4-dioxan-2-one (PDX) monomer in a twin-screw extruder using Aluminum tri-sec butoxide (ATSB) initiator. Good and accurate control over molecular weight was obtained by controlling the ratio of monomer to initiator. A screw configuration consisting of only conveying elements was used for the polymerization. The polymerization reaction was characterized by a monomer-polymer dynamic equilibrium, above the melting temperature of the polymer, limiting the equilibrium conversion to 78-percent. Near complete (˜100-percent) conversion was obtained on co-polymerizing PDX monomer with a few mol-percent (around 8-percent) Caprolactone (CL) monomer in a twin-screw extruder using ATSB initiator. The co-polymers exhibited improved thermal stability with reduction in glass transition temperature. The extruder was modeled as an Axial Dispersed Plug Flow Reactor for the polymerization of CL monomer using Residence Time Distribution (RTD) Analysis. The model provided a good fit to the experimental RTD and conversion data. Aliphatic and aliphatic-aromatic co-polyesters, namely Polycaprolactone (PCL) and Poly butylenes (adipate-co-terephthalate) (Ecoflex) were cross-linked in a twin-screw extruder using radical initiator to form micro-gel reinforced biodegradable polyesters. Cross-linked Ecoflex was further extrusion blended with talc to form blends suitable to be blown into films. A screw configuration consisting of conveying and kneading elements was found to be effective in dispersion of the talc particles (5--10 microns) in the polyester matrix. While the rates of crystallization increased for the talc filled polyester blends, overall crystallinity reduced. Mechanical, tear and puncture properties of films made using the talc filled polyester blends

  17. A comparative study among different photochemical oxidation processes to enhance the biodegradability of paper mill wastewater.

    PubMed

    Jamil, Tarek S; Ghaly, Montaser Y; El-Seesy, Ibrahim E; Souaya, Eglal R; Nasr, Rabab A

    2011-01-15

    Advanced oxidation processes including UV, UV/H(2)O(2), Fenton reaction (Fe(II)/H(2)O(2)) and photo-Fenton process (Fe(II)/H(2)O(2)/UV) for the treatment of paper mill wastewater will be investigated. A comparison among these techniques is undertaken with respect to the decrease of chemical oxygen demand (COD) and total suspended solids (TSS) and the evolution of chloride ions. Optimum operating conditions for each process under study revealed the effect of the initial amounts of Fe(II) and hydrogen peroxide. Of the tested processes, photo-Fenton process was found to be the fastest one with respect to COD and TSS reduction of the wastewater within 45 min reaction time under low amounts of Fe(II) and hydrogen peroxide of 0.5 and 1.5mg/L, respectively, and amounted to 79.6% and 96.6% COD and TSS removal. The initial biodegradability of the organic matter present in the effluent, estimated as the BOD(5)/COD, was low 0.21. When the effluent was submitted to the different types of AOPs used in this study, the biodegradability increases significantly. Within 45 min of reaction time, the photo-Fenton process appears as the most efficient process in the enhancement of the biodegradability of the organic matter in the effluent and the BOD(5)/COD ratio increased from 0.21 to 0.7.

  18. Aerobic Biodegradation of Fuel Oxygenates

    DTIC Science & Technology

    2007-06-01

    microbial attack. MTBE is a colorless flammable liquid with a distinct taste and odor (ATSDR, 1997). MTBE’s very low taste and odor threshold, at...based oxygenates chemical structure is characterized by the addition of a hydroxyl (O-H) group bonded to an alkyl group. This removal of a hydrogen and...OSHA, 1996). Once TBA reaches its melting point of 25.6o C (78.1o F) it forms a flammable, volatile, clear liquid . The presence of TBA in many

  19. Effects of aerobic exercise under different thermal conditions on human somatosensory processing.

    PubMed

    Nakata, Hiroki; Oshiro, Misaki; Namba, Mari; Shibasaki, Manabu

    2016-10-01

    The present study aimed to investigate the effects of aerobic exercise on human somatosensory processing recorded by somatosensory evoked potentials (SEPs) under temperate [TEMP, 20°C and 40% relative humidity (RH)] and hot (HOT, 35°C and 30% RH) environments. Fifteen healthy subjects performed 4 × 15-min bouts of a moderate cycling exercise [mean power output: 156.5 ± 7.7 (SE) W], with a 10-min rest period and received a posterior tibial nerve stimulation at the left ankle before and after each exercise bout; SEPs were recorded in five sessions; 1st (pre), 2nd (post-1st exercise bout), 3rd (post-2nd exercise bout), 4th (post-3rd exercise bout), and 5th (post-4th exercise bout). The peak latencies and amplitudes of the P37, N50, P60, and N70 components at Cz were evaluated. The latencies of P37, N50, P60, and N70 were significantly shorter with the repetition of aerobic exercise, and these shortened latencies were significantly greater in the HOT condition than in the TEMP condition (P37: 3rd, P < 0.05, and 5th, P < 0.01; P60: 4th, P < 0.05, and 5th, P < 0.01; N70: 4th, P < 0.05, and 5th, P < 0.001). No significant differences were observed in the amplitudes of any SEP component under either thermal condition. These results suggest that the conduction velocity of the ascending somatosensory input was accelerated by increases in body temperature, and aerobic exercise did not alter the strength of neural activity in cortical somatosensory processing.

  20. Biodegradation of fat, oil and grease (FOG) deposits under various redox conditions relevant to sewer environment.

    PubMed

    He, Xia; Zhang, Qian; Cooney, Michael J; Yan, Tao

    2015-07-01

    Fat, oil and, grease (FOG) deposits are one primary cause of sanitary sewer overflows (SSOs). While numerous studies have examined the formation of FOG deposits in sewer pipes, little is known about their biodegradation under sewer environments. In this study, FOG deposit biodegradation potential was determined by studying the biodegradation of calcium palmitate in laboratory under aerobic, nitrate-reducing, sulfate-reducing, and methanogenic conditions. Over 110 days of observation, calcium palmitate was biodegraded to CO2 under aerobic and nitrate-reducing conditions. An approximate 13 times higher CO2 production rate was observed under aerobic condition than under nitrate-reducing condition. Under sulfate-reducing condition, calcium palmitate was recalcitrant to biodegradation as evidenced by small reduction in sulfate. No evidence was found to support calcium palmitate degradation under methanogenic condition in the simulated sewer environment. Dominant microbial populations in the aerobic and nitrate-reducing microcosms were identified by Illumina seqeuncing, which may contain the capability to degrade calcium palmitate under both aerobic and nitrate-reducing conditions. Further study on these populations and their functional genes could shed more light on this microbial process and eventually help develop engineering solutions for SSOs control in the future.

  1. Phthalate esters in the environment: A critical review of their occurrence, biodegradation, and removal during wastewater treatment processes.

    PubMed

    Gao, Da-Wen; Wen, Zhi-Dan

    2016-01-15

    Phthalate esters are one of the most frequently detected persistent organic pollutants in the environment. A better understanding of their occurrence and degradation in the environment and during wastewater treatment processes will facilitate the development of strategies to reduce these pollutants and to bioremediate contaminated freshwater and soil. Phthalate esters occur at measurable levels in different environments worldwide. For example, the concentrations of dimethyl phthalate (DMP) in atmospheric particulate matter, fresh water and sediments, soil, and landfills are N.D.-10.4 ng/m(3), N.D.-31.7 μg/L, N.D.-316 μg/kg dry weight, and N.D.-200 μg/kg dry weight, N.D.-43.27 μg/L, respectively. Bis(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) are primary phthalate ester pollutants. Urbanization has increased the discharge of phthalate esters to atmospheric and aquatic environments, and the use of agricultural plastics has exacerbated soil contamination by phthalate esters in rural areas. Aerobic biodegradation is the primary manner of phthalate ester mineralization in the environment, and this process has been widely studied. Phthalate esters can be removed during wastewater treatment processes. The combination of different wastewater treatment technologies showed greater efficiency in the removal of phthalate esters than individual treatment steps, such as the combination of anaerobic wastewater treatment with a membrane bioreactor would increase the efficiency of phthalate ester removal from 65%-71% to 95%-97%. This review provides a useful framework to identify future research objectives to achieve the mineralization and elimination of phthalate esters in the environment.

  2. Characteristics of Biological Nitrogen Removal in a Multiple Anoxic and Aerobic Biological Nutrient Removal Process

    PubMed Central

    Wang, Huoqing; Guan, Yuntao; Li, Li; Wu, Guangxue

    2015-01-01

    Two sequencing batch reactors, one with the conventional anoxic and aerobic (AO) process and the other with the multiple AO process, were operated to examine characteristics of biological nitrogen removal, especially of the multiple AO process. The long-term operation showed that the total nitrogen removal percentage of the multiple AO reactor was 38.7% higher than that of the AO reactor. In the multiple AO reactor, at the initial SBR cycle stage, due to the occurrence of simultaneous nitrification and denitrification, no nitrite and/or nitrate were accumulated. In the multiple AO reactor, activities of nitrite oxidizing bacteria were inhibited due to the multiple AO operating mode applied, resulting in the partial nitrification. Denitrifiers in the multiple AO reactor mainly utilized internal organic carbon for denitrification, and their activities were lower than those of denitrifiers in the AO reactor utilizing external organic carbon. PMID:26491676

  3. Biodegradability and toxicity assessment of a real textile wastewater effluent treated by an optimized electrocoagulation process.

    PubMed

    Manenti, Diego R; Módenes, Aparecido N; Soares, Petrick A; Boaventura, Rui A R; Palácio, Soraya M; Borba, Fernando H; Espinoza-Quiñones, Fernando R; Bergamasco, Rosângela; Vilar, Vítor J P

    2015-01-01

    In this work, the application of an iron electrode-based electrocoagulation (EC) process on the treatment of a real textile wastewater (RTW) was investigated. In order to perform an efficient integration of the EC process with a biological oxidation one, an enhancement in the biodegradability and low toxicity of final compounds was sought. Optimal values of EC reactor operation parameters (pH, current density and electrolysis time) were achieved by applying a full factorial 3(3) experimental design. Biodegradability and toxicity assays were performed on treated RTW samples obtained at the optimal values of: pH of the solution (7.0), current density (142.9 A m(-2)) and different electrolysis times. As response variables for the biodegradability and toxicity assessment, the Zahn-Wellens test (Dt), the ratio values of dissolved organic carbon (DOC) relative to low-molecular-weight carboxylates anions (LMCA) and lethal concentration 50 (LC50) were used. According to the Dt, the DOC/LMCA ratio and LC50, an electrolysis time of 15 min along with the optimal values of pH and current density were suggested as suitable for a next stage of treatment based on a biological oxidation process.

  4. Kinetics and mechanism of the biodegradation of PLA/clay nanocomposites during thermophilic phase of composting process.

    PubMed

    Stloukal, Petr; Pekařová, Silvie; Kalendova, Alena; Mattausch, Hannelore; Laske, Stephan; Holzer, Clemens; Chitu, Livia; Bodner, Sabine; Maier, Guenther; Slouf, Miroslav; Koutny, Marek

    2015-08-01

    The degradation mechanism and kinetics of polylactic acid (PLA) nanocomposite films, containing various commercially available native or organo-modified montmorillonites (MMT) prepared by melt blending, were studied under composting conditions in thermophilic phase of process and during abiotic hydrolysis and compared to the pure polymer. Described first order kinetic models were applied on the data from individual experiments by using non-linear regression procedures to calculate parameters characterizing aerobic composting and abiotic hydrolysis, such as carbon mineralization, hydrolysis rate constants and the length of lag phase. The study showed that the addition of nanoclay enhanced the biodegradation of PLA nanocomposites under composting conditions, when compared with pure PLA, particularly by shortening the lag phase at the beginning of the process. Whereas the lag phase of pure PLA was observed within 27days, the onset of CO2 evolution for PLA with native MMT was detected after just 20days, and from 13 to 16days for PLA with organo-modified MMT. Similarly, the hydrolysis rate constants determined tended to be higher for PLA with organo-modified MMT, particularly for the sample PLA-10A with fastest degradation, in comparison with pure PLA. The acceleration of chain scission in PLA with nanoclays was confirmed by determining the resultant rate constants for the hydrolytical chain scission. The critical molecular weight for the hydrolysis of PLA was observed to be higher than the critical molecular weight for onset of PLA mineralization, suggesting that PLA chains must be further shortened so as to be assimilated by microorganisms. In conclusion, MMT fillers do not represent an obstacle to acceptance of the investigated materials in composting facilities.

  5. Pseudomonads biodegradation of aromatic compounds in oil sands process-affected water.

    PubMed

    Zhang, Yanyan; McPhedran, Kerry N; Gamal El-Din, Mohamed

    2015-07-15

    Aromatic naphthenic acids (NAs) have been shown to be more toxic than the classical NAs found in oil sands process-affected water (OSPW). To reduce this toxicity, Pseudomonas fluorescens and Pseudomonas putida were used to determine their ability to biodegrade aromatic compounds including treatments considering the impacts of external carbon and iron addition. Results showed that with added carbon P. fluorescens and P. putida have the capability of biodegrading these aromatics. In the presence of external carbon, gene expression of a functional PAH-ring hydroxylating dioxygenase (PAH-RHDα) was determined through reverse transcription real-time PCR, suggesting active degradation of OSPW aromatic compounds. Although no significant classical NAs removal was observed during this process, toxicity was reduced by 49.3% under optimal conditions. OSPW toxicity was eliminated with the combination of ozonation at a dose of 80 mg/L followed by biodegradation, indicating that it is a promising combined OSPW treatment approach for the safe discharge to the aquatic environment.

  6. A quantitative framework for understanding complex interactions between competing interfacial processes and in situ biodegradation

    NASA Astrophysics Data System (ADS)

    Johnson, Mark A.; Song, Xin; Seagren, Eric A.

    2013-03-01

    In situ bioremediation of contaminated groundwater is made technologically challenging by the physically, chemically, and biologically heterogeneous subsurface environment. Subsurface heterogeneities are important because of influences on interfacial mass transfer processes that impact the availability of substrates to microorganisms. The goal of this study was to perform a "proof-of-concept" evaluation of the utility of a quantitative framework based on a set of dimensionless coefficients for evaluating the effects of competing physicochemical interfacial and biokinetic processes at the field scale. First, three numerical modeling experiments were completed, demonstrating how the framework can be used to identify the rate-limiting process for the overall bioremediation rate, and to predict what engineered enhancements will alleviate the rate-limiting process. Baseline conditions for each scenario were established to examine intrinsic biodegradation with a given rate-limiting process (either dispersion, biokinetics, or sorption). Then different engineering treatments were examined. In each case, the treatment predicted to be appropriate for addressing the overall rate-limiting process based on the quantitative framework alleviated the limitation more successfully, and enhanced the in situ biodegradation rate more than the alternative enhancements. Second, the quantitative framework was applied to a series of large-scale laboratory and field-scale experiments, using reported parameter estimates to calculate the relevant dimensionless coefficients and predict the rate-limiting process(es). Observations from the studies were then used to evaluate those predictions.

  7. A quantitative framework for understanding complex interactions between competing interfacial processes and in situ biodegradation.

    PubMed

    Johnson, Mark A; Song, Xin; Seagren, Eric A

    2013-03-01

    In situ bioremediation of contaminated groundwater is made technologically challenging by the physically, chemically, and biologically heterogeneous subsurface environment. Subsurface heterogeneities are important because of influences on interfacial mass transfer processes that impact the availability of substrates to microorganisms. The goal of this study was to perform a "proof-of-concept" evaluation of the utility of a quantitative framework based on a set of dimensionless coefficients for evaluating the effects of competing physicochemical interfacial and biokinetic processes at the field scale. First, three numerical modeling experiments were completed, demonstrating how the framework can be used to identify the rate-limiting process for the overall bioremediation rate, and to predict what engineered enhancements will alleviate the rate-limiting process. Baseline conditions for each scenario were established to examine intrinsic biodegradation with a given rate-limiting process (either dispersion, biokinetics, or sorption). Then different engineering treatments were examined. In each case, the treatment predicted to be appropriate for addressing the overall rate-limiting process based on the quantitative framework alleviated the limitation more successfully, and enhanced the in situ biodegradation rate more than the alternative enhancements. Second, the quantitative framework was applied to a series of large-scale laboratory and field-scale experiments, using reported parameter estimates to calculate the relevant dimensionless coefficients and predict the rate-limiting process(es). Observations from the studies were then used to evaluate those predictions.

  8. Mathematical modeling of the effects of aerobic and anaerobic chelate bioegradation on actinide speciation.

    SciTech Connect

    Banaszak, J.E.; VanBriesen, J.; Rittmann, B.E.; Reed, D.T.

    1998-03-19

    Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and, hence, the mobility of actinides in subsurface environments. We combined mathematical modeling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bio-utilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modeling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems.

  9. An adsorption-release-biodegradation system for simultaneous biodegradation of phenol and ammonium in phenol-rich wastewater.

    PubMed

    Wang, Ying; Chen, Hu; Liu, Yu-Xiang; Ren, Rui-Peng; Lv, Yong-Kang

    2016-07-01

    The feasibility of simultaneous biodegradation of phenol and ammonium in phenol-rich wastewater was evaluated in a reusable system, which contained macroporous adsorption resin and Alcaligenes faecalis strain WY-01. In the system, up to 6000mg/L phenol could be completely degraded by WY-01; meanwhile, 99.03±3.95% of ammonium was removed from the initial concentration of 384mg/L. This is the first study to show the capability of single strain in simultaneous removal of ammonium and phenol in wastewater containing such high concentrations of phenol. Moreover, the resin was regenerated during the biodegradation process without any additional manipulations, indicating the system was reusable. Furthermore, enzyme assay, gene expression patterns, HPLC-MS and gas chromatography analysis confirmed that phenol biodegradation accompanied with aerobic nitrifier denitrification process. Results imply that the reusable system provides a novel strategy for more efficient biodegradation of phenol and ammonium contained in some particular industrial wastewater.

  10. Decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process.

    PubMed

    Mohd Nasir, Norlirubayah; Teo Ming, Ting; Ahmadun, Fakhru'l-Razi; Sobri, Shafreeza

    2010-01-01

    The research conducted a study on decomposition and biodegradability enhancement of textile wastewater using a combination of electron beam irradiation and activated sludge process. The purposes of this research are to remove pollutant through decomposition and to enhance the biodegradability of textile wastewater. The wastewater is treated using electron beam irradiation as a pre-treatment before undergo an activated sludge process. As a result, for non-irradiated wastewater, the COD removal was achieved to be between 70% and 79% after activated sludge process. The improvement of COD removal efficiency increased to 94% after irradiation of treated effluent at the dose of 50 kGy. Meanwhile, the BOD(5) removal efficiencies of non-irradiated and irradiated textile wastewater were reported to be between 80 and 87%, and 82 and 99.2%, respectively. The maximum BOD(5) removal efficiency was achieved at day 1 (HRT 5 days) of the process of an irradiated textile wastewater which is 99.2%. The biodegradability ratio of non-irradiated wastewater was reported to be between 0.34 and 0.61, while the value of biodegradability ratio of an irradiated wastewater increased to be between 0.87 and 0.96. The biodegradability enhancement of textile wastewater is increased with increasing the doses. Therefore, an electron beam radiation holds a greatest application of removing pollutants and also on enhancing the biodegradability of textile wastewater.

  11. Effect of fabrication and processing technology on the biodegradability of magnesium nanocomposites.

    PubMed

    Ma, Chao; Chen, Lianyi; Xu, Jiaquan; Fehrenbacher, Axel; Li, Yan; Pfefferkorn, Frank E; Duffie, Neil A; Zheng, Jing; Li, Xiaochun

    2013-07-01

    Magnesium and its alloys have gained significant attention recently as potential alternatives for biodegradable materials due to their unique biodegradability, biocompatibility, and mechanical properties. However, magnesium alloys tend to have high corrosion rates in biological liquids, thus presenting a potential problem if a magnesium implant/device needs to maintain mechanical integrity for a sufficient period under practical physiological conditions. In this study, hydroxyapatite nanoparticles were used to form magnesium based metal matrix nanocomposites (MMNC) through two processes: friction stir processing (FSP) and a two-state nanoprocessing (TSnP) combining liquid state ultrasonic processing and solid state FSP. In addition, laser surface melting (LSM) was carried out for further surface treatment. In vitro immersion tests indicated that the corrosion rate of MMNC decreased by 52% compared with pure Mg through FSP. Potentiodynamic polarization tests showed that the corrosion current of MMNC decreased by 71% and 30%, respectively, by TSnP and LSM when compared with pure Mg or untreated counterparts. This study suggests that fabrication of MMNC and further processing through FSP and LSM can robustly enhance the corrosion resistance of magnesium, which will boost its potential for biological applications.

  12. The processing of ultrafine-grained Mg tubes for biodegradable stents.

    PubMed

    Ge, Qiang; Dellasega, David; Demir, Ali Gökhan; Vedani, Maurizio

    2013-11-01

    An investigation was carried out on equal-channel angular pressing (ECAP) and extrusion processing of a ZM21 Mg alloy to obtain an improved candidate material for the manufacturing of biodegradable Mg stents. Ultrafine-grain size billets of the ZM21 alloy were obtained by two-stage ECAP aimed at achieving an initial refining of the structure at 200°C and then reaching the submicrometer grain size range by lowering the processing temperature down to 150°C. The investigation revealed a significant improvement in the properties of the ECAP-treated samples compared with the starting coarse-grained ZM21 alloy. The 0.2% yield strength rose from 180 to 340 MPa after 150°C ECAP processing, while maintaining a fairly high tensile ductility. The ultrafine ZM21 alloy billets were then used for the extrusion of stent precursors having the form of small-size tubes. The grain size after extrusion remained in the submicrometer range while the hardness was revealed to be significantly higher than that of the coarse-grained ZM21 Mg alloy. It was demonstrated that processing of biodegradable Mg stent having an ultrafine-grained microstructure by ECAP and low-temperature extrusion is feasible and that the obtained products feature promising properties.

  13. Characterization of aerobic spore-forming bacteria associated with industrial dairy processing environments and product spoilage.

    PubMed

    Lücking, Genia; Stoeckel, Marina; Atamer, Zeynep; Hinrichs, Jörg; Ehling-Schulz, Monika

    2013-09-02

    Due to changes in the design of industrial food processing and increasing international trade, highly thermoresistant spore-forming bacteria are an emerging problem in food production. Minimally processed foods and products with extended shelf life, such as milk products, are at special risk for contamination and subsequent product damages, but information about origin and food quality related properties of highly heat-resistant spore-formers is still limited. Therefore, the aim of this study was to determine the biodiversity, heat resistance, and food quality and safety affecting characteristics of aerobic spore-formers in the dairy sector. Thus, a comprehensive panel of strains (n=467), which originated from dairy processing environments, raw materials and processed foods, was compiled. The set included isolates associated with recent food spoilage cases and product damages as well as isolates not linked to product spoilage. Identification of the isolates by means of Fourier-transform infrared spectroscopy and molecular methods revealed a large biodiversity of spore-formers, especially among the spoilage associated isolates. These could be assigned to 43 species, representing 11 genera, with Bacillus cereus s.l. and Bacillus licheniformis being predominant. A screening for isolates forming thermoresistant spores (TRS, surviving 100°C, 20 min) showed that about one third of the tested spore-formers was heat-resistant, with Bacillus subtilis and Geobacillus stearothermophilus being the prevalent species. Strains producing highly thermoresistant spores (HTRS, surviving 125°C, 30 min) were found among mesophilic as well as among thermophilic species. B. subtilis and Bacillus amyloliquefaciens were dominating the group of mesophilic HTRS, while Bacillus smithii and Geobacillus pallidus were dominating the group of thermophilic HTRS. Analysis of spoilage-related enzymes of the TRS isolates showed that mesophilic strains, belonging to the B. subtilis and B. cereus

  14. Acute aerobic exercise influences the inhibitory process in the go/no-go task in humans.

    PubMed

    Akatsuka, Kosuke; Yamashiro, Koya; Nakazawa, Sho; Mitsuzono, Ryouichi; Maruyama, Atsuo

    2015-07-23

    This study evaluated the influence of acute aerobic exercise on the human inhibitory system. For studies on the neural mechanisms of somato-motor inhibitory processing in humans, the go/no-go task is a useful paradigm for recording event-related potentials. Ten subjects performed somatosensory go/no-go tasks in a control condition and exercise condition. In the control condition, the subjects performed the go/no-go task before and after 20 min of rest. In the exercise condition, the subjects performed the go/no-go task before and after 15 min of treadmill running with the exercise intensity set individually for each subject at 50% of peak oxygen intake. We successfully recorded a clear-cut N140 component under all conditions, and found that the peak amplitude of no-go-N140 at Fz and Cz was significantly enhanced during moderate exercise. In contrast, there were no significant changes in Fz and Cz in the control condition. These results suggest that moderate exercise can affect the amplitude of no-go-N140, which could be interpreted as an index of the human inhibition process in the central nervous system. The human inhibitory system is an important cognitive process, and this system may underlie the hypothetical ability of physical exercise to maintain and improve cognitive performance throughout the lifespan.

  15. Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration.

    PubMed

    Widmer, M S; Gupta, P K; Lu, L; Meszlenyi, R K; Evans, G R; Brandt, K; Savel, T; Gurlek, A; Patrick, C W; Mikos, A G

    1998-11-01

    We have fabricated porous, biodegradable tubular conduits for guided tissue regeneration using a combined solvent casting and extrusion technique. The biodegradable polymers used in this study were poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). A polymer/salt composite was first prepared by a solvent casting process. After drying, the composite was extruded to form a tubular construct. The salt particles in the construct were then leached out leaving a conduit with an open-pore structure. PLGA was studied as a model polymer to analyze the effects of salt weight fraction, salt particle size, and processing temperature on porosity and pore size of the extruded conduits. The porosity and pore size were found to increase with increasing salt weight fraction. Increasing the salt particle size increased the pore diameter but did not affect the porosity. High extrusion temperatures decreased the pore diameter without altering the porosity. Greater decrease in molecular weight was observed for conduits manufactured at higher temperatures. The mechanical properties of both PLGA and PLLA conduits were tested after degradation in vitro for up to 8 weeks. The modulus and failure strength of PLLA conduits were approximately 10 times higher than those of PLGA conduits. Failure strain was similar for both conduits. After degradation for 8 weeks, the molecular weights of the PLGA and PLLA conduits decreased to 38% and 43% of the initial values, respectively. However, both conduits maintained their shape and did not collapse. The PLGA also remained amorphous throughout the time course, while the crystallinity of PLLA increased from 5.2% to 11.5%. The potential of seeding the conduits with cells for transplantation or with biodegradable polymer microparticles for drug delivery was also tested with dyed microspheres. These porous tubular structures hold great promise for the regeneration of tissues which require tubular scaffolds such as peripheral nerve

  16. Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration

    NASA Technical Reports Server (NTRS)

    Widmer, M. S.; Gupta, P. K.; Lu, L.; Meszlenyi, R. K.; Evans, G. R.; Brandt, K.; Savel, T.; Gurlek, A.; Patrick, C. W. Jr; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    We have fabricated porous, biodegradable tubular conduits for guided tissue regeneration using a combined solvent casting and extrusion technique. The biodegradable polymers used in this study were poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). A polymer/salt composite was first prepared by a solvent casting process. After drying, the composite was extruded to form a tubular construct. The salt particles in the construct were then leached out leaving a conduit with an open-pore structure. PLGA was studied as a model polymer to analyze the effects of salt weight fraction, salt particle size, and processing temperature on porosity and pore size of the extruded conduits. The porosity and pore size were found to increase with increasing salt weight fraction. Increasing the salt particle size increased the pore diameter but did not affect the porosity. High extrusion temperatures decreased the pore diameter without altering the porosity. Greater decrease in molecular weight was observed for conduits manufactured at higher temperatures. The mechanical properties of both PLGA and PLLA conduits were tested after degradation in vitro for up to 8 weeks. The modulus and failure strength of PLLA conduits were approximately 10 times higher than those of PLGA conduits. Failure strain was similar for both conduits. After degradation for 8 weeks, the molecular weights of the PLGA and PLLA conduits decreased to 38% and 43% of the initial values, respectively. However, both conduits maintained their shape and did not collapse. The PLGA also remained amorphous throughout the time course, while the crystallinity of PLLA increased from 5.2% to 11.5%. The potential of seeding the conduits with cells for transplantation or with biodegradable polymer microparticles for drug delivery was also tested with dyed microspheres. These porous tubular structures hold great promise for the regeneration of tissues which require tubular scaffolds such as peripheral nerve

  17. Effects of process stability on anaerobic biodegradation of LAS in UASB reactors.

    PubMed

    Løbner, Trine; Toräng, Lars; Batstone, Damien John; Schmidt, Jens Ejbye; Angelidaki, Irini

    2005-03-30

    Anaerobic biodegradation of linear alkylbenzene sulfonates (LAS) was studied in upflow anaerobic sludge blanket (UASB) reactors operated under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. LAS C12 concentration in the influents was 10 mg.L(-1), and the hydraulic retention time in the reactors was 2 days. Adsorption of LAS C12 was assessed in an autoclaved control reactor and ceased after 115 days. The reactors were operated for a minimum of 267 days; 40-80% removal of LAS C12 was observed. A temperature reduction from 55 degrees C to 32 degrees C for 30 h resulted in process imbalance as indicated by increase of volatile fatty acids (VFA). The imbalance was much more intense in the LAS amended reactor compared with an unamended reactor. At the same time, the process imbalance resulted in discontinued LAS removal. This finding indicates that process stability is a key factor in anaerobic biological removal of LAS. After a recovery period, the removal of LAS resumed, providing evidence of biological anaerobic LAS degradation. The removal remained constant until termination of experiments in the reactor. Biodegradation of LAS in the mesophilic reactor was at the same level as in the thermophilic reactor under stable conditions.

  18. Marine Oil Biodegradation

    SciTech Connect

    Hazen, Terry C.; Prince, Roger; Mahmoudi, Nagissa

    2015-12-23

    Crude oil has been part of the marine environment for millions of years, and microbes that use its rich source of energy and carbon are found in seawater, sediments and shorelines from the tropics to the polar regions. Catastrophic oil spills stimulate these organisms to ‘bloom’ in a reproducible fashion, and although oil does not provide bioavailable nitrogen, phosphorus or iron, there are enough of these nutrients in the sea that when dispersed oil droplets dilute to low concentrations these low levels are adequate for microbial growth. Most of the hydrocarbons in dispersed oil are degraded in aerobic marine waters with a half-life of days to months. In contrast, oil that reaches shorelines is likely to be too concentrated, have lower levels of nutrients, and have a far longer residence time in the environment. Oil that becomes entrained in anaerobic sediments is also likely to have a long residence time, although it too will eventually be biodegraded. Thus, data that encompass everything from the ecosystem to the molecular level are needed for understanding the complicated process of petroleum biodegradation in marine environments.

  19. Marine Oil Biodegradation

    DOE PAGES

    Hazen, Terry C.; Prince, Roger; Mahmoudi, Nagissa

    2015-12-23

    Crude oil has been part of the marine environment for millions of years, and microbes that use its rich source of energy and carbon are found in seawater, sediments and shorelines from the tropics to the polar regions. Catastrophic oil spills stimulate these organisms to ‘bloom’ in a reproducible fashion, and although oil does not provide bioavailable nitrogen, phosphorus or iron, there are enough of these nutrients in the sea that when dispersed oil droplets dilute to low concentrations these low levels are adequate for microbial growth. Most of the hydrocarbons in dispersed oil are degraded in aerobic marine watersmore » with a half-life of days to months. In contrast, oil that reaches shorelines is likely to be too concentrated, have lower levels of nutrients, and have a far longer residence time in the environment. Oil that becomes entrained in anaerobic sediments is also likely to have a long residence time, although it too will eventually be biodegraded. Thus, data that encompass everything from the ecosystem to the molecular level are needed for understanding the complicated process of petroleum biodegradation in marine environments.« less

  20. Marine Oil Biodegradation.

    PubMed

    Hazen, Terry C; Prince, Roger C; Mahmoudi, Nagissa

    2016-03-01

    Crude oil has been part of the marine environment for millions of years, and microbes that use its rich source of energy and carbon are found in seawater, sediments, and shorelines from the tropics to the polar regions. Catastrophic oil spills stimulate these organisms to "bloom" in a reproducible fashion, and although oil does not provide bioavailable nitrogen, phosphorus or iron, there are enough of these nutrients in the sea that when dispersed oil droplets dilute to low concentrations these low levels are adequate for microbial growth. Most of the hydrocarbons in dispersed oil are degraded in aerobic marine waters with a half-life of days to months. In contrast, oil that reaches shorelines is likely to be too concentrated, have lower levels of nutrients, and have a far longer residence time in the environment. Oil that becomes entrained in anaerobic sediments is also likely to have a long residence time, although it too will eventually be biodegraded. Thus, data that encompass everything from the ecosystem to the molecular level are needed for understanding the complicated process of petroleum biodegradation in marine environments.

  1. Anaerobic and aerobic transformation of TNT

    SciTech Connect

    Kulpa, C.F.; Boopathy, R.; Manning, J.

    1996-12-31

    Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The data supporting the anaerobic transformation of TNT under different growth condition are reviewed in this report.

  2. Microbial community analysis involved in the aerobic/extended-idle process performing biological phosphorus removal.

    PubMed

    Zeng, Tian-jing; Yang, Guo-jing; Wang, Dong-bo; Li, Xiao-ming; Zheng, Wei; Yang, Qi; Zeng, Guang-ming

    2013-01-01

    Recently, it has been found that biological phosphorus removal can be achieved in an aerobic/extended-idle (AEI) process using both glucose and acetate as the sole substrate. However, the microbial consortiums involved in glucose-fed and acetate-fed systems have not yet been characterized. Thus the aims of this paper were to investigate the diversities and dynamics of bacterial communities during the acclimation period, and to quantify polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in the systems. The phylogenetic analysis showed that the microbial communities were mainly composed of phylum Proteobacteria, Bacteroidetes, Chlorobi and another six kinds of unclassified bacteria. Fluorescence in-situ hybridization (FISH) analysis revealed that PAOs and GAOs accounted for 43 ± 7 and 16 ± 3% of all bacteria in the glucose-fed system, and 19 ± 4 and 35 ± 5% of total bacteria in the acetate-fed system, respectively. The results showed that the conventional PAOs could thrive in the AEI process, and a defined anaerobic zone was not necessarily required for putative PAOs growth.

  3. Use of advanced oxidation processes to improve the biodegradability of mature landfill leachates.

    PubMed

    de Morais, Josmaria Lopes; Zamora, Patricio Peralta

    2005-08-31

    Two advanced oxidative processes (Fe2+/H2O2/UV and H2O2/UV systems) were used for the pre-treatment of mature landfill leachate with the objective of improving its overall biodegradability, evaluated in terms of BOD5/COD ratio, up to a value compatible with biological treatment. At optimized experimental conditions (2000 mgL(-1) of H2O2 and 10 mgL(-1) of Fe2+ for the photo-Fenton system, and 3000 mgL(-1) of H2O2 for the H2O2/UV system), both methods showed suitability for partial removal of chemical oxygen demand (COD), total organic carbon (TOC) and color. The biodegradability was significantly improved (BOD5/COD from 0.13 to 0.37 or 0.42) which allowed an almost total removal of COD and color by a sequential activated sludge process. In addition, gel permeation chromatography (GPC) has showed a substantial agreement on the cleavage of large organic compound into smaller ones.

  4. Methane potential and biodegradability of rice straw, rice husk and rice residues from the drying process.

    PubMed

    Contreras, L M; Schelle, H; Sebrango, C R; Pereda, I

    2012-01-01

    Agricultural solid residues are a potential renewable energy source. Rice harvesting and production in Sancti Spíritus province, Cuba, currently generates residues without an environmentally sustainable disposal route. Rice residues (rice straw, rice husk and rice residues from the drying process) are potentially an important carbon source for anaerobic digestion. For this paper, rice residues were placed for 36 days retention time in anaerobic batch reactor environments at both mesophilic (37 °C) and thermophilic (55 °C) conditions. Biogas and methane yield were determined as well as biogas composition. The results showed that rice straw as well as rice residues from the drying process had the highest biogas and methane yield. Temperature played an important role in determining both biogas yield and kinetics. In all cases, rice straw produced the highest yields; under mesophilic conditions the biogas yield was 0.43 m(3) kg(VS)(-1), under thermophilic conditions biogas yield reached 0.52 m(3) kg(VS)(-1). In the case of the rice husk, the biodegradability was very low. Methane content in all batches was kept above 55% vol. All digested material had a high carbon:nitrogen (C:N) ratio, even though significant biodegradation was recorded with the exception of rice husk. A first-order model can be used to describe the rice crop residues fermentation effectively.

  5. Treatment of non-biodegradable cutting oil wastewater by ultrasonication-Fenton oxidation process.

    PubMed

    Seo, D C; Lee, H J; Hwang, H N; Park, M R; Kwak, N W; Cho, I J; Cho, J S; Seo, J Y; Joo, W H; Park, K H; Heo, J S

    2007-01-01

    To treat cutting oil wastewater produced in metal surface treatment industry, Ultrasonication (US)-Fenton process, which is one of the advanced oxidation processes, was used. The optimum conditions to treat non-biodegradable pollutants using the US-Fenton process were that the application rates of H2O2 and FeSO4 were 10% and 3 g/L, respectively, the value of pH was 3, and the ultrasonication time was 30 min. It identified non-degradable pollutants such as ethylene diamine tetraacetic acid (EDTA) and Triethanolamine (TEA) in the cutting oil wastewater. TLC analysis of two compounds of treated water by the coagulation process was similar to that of raw water. However, TLC analysis of two compounds of US-Fenton process was different from that of raw water, meaning that US-Fenton process decomposed the EDTA and TEA. To study the possibility of application with the US-Fenton process to pilot plant, the pollutants treatment efficiency of three different methods, such as US-Fenton process, activated sludge process and coagulation process, in continuous experiments were compared. The removal rate of pollutants by the US-Fenton process according to the effluent time was higher than any other processes. The removal rates of COD, SS, T-N and T-P by US-Fenton process were 98, 93, 75 and 95%, respectively.

  6. Fabrication of biodegradable polyurethane microspheres by a facile and green process.

    PubMed

    Lin, Cheng-Yen; Hsu, Shan-hui

    2015-05-01

    Two different compositions of water-based biodegradable polyurethane (PU) in the form of homogeneous nanoparticles (NPs) were synthesized using biodegradable polyesters as the soft segment. The first PU (PU01) was based on poly(ε-caprolactone) (PCL) diol and the second PU (PU02) was based on 40% PCL diol and 60% polyethylene butylene adipate diol. The PU NP dispersions with different solid contents were sprayed into liquid nitrogen and resuspended in water to generate elastic microspheres (50-60 µm) with different nanoporosities. In vitro degradation analysis revealed that microspheres of PU02 (i.e., PU02 MS) degraded faster than those of PU01 (PU01 MS). Methylene blue was encapsulated during microsphere formation and the release was investigated. Microspheres made from a lower content (10%) of PU02 dispersion (i.e., PU02 MS_10) showed a greater burst release of methylene blue in 6 h, whereas those made from a higher content (30%) of PU01 dispersion (i.e., PU01 MS_30) revealed a prolonged release with a significantly lower burst release. Biocompatibility evaluation using L929 fibroblasts demonstrated that cells were attached and proliferated on microspheres after 24 h. On the other hand, microspheres may further self-assemble into films and scaffolds. Surface modification of microspheres by chitosan may modify the self-assembly behavior of microspheres. Microspheres could be stacked to form scaffolds with different macroporosities. Fibroblasts were successfully seeded and grown in the microsphere-stacked scaffolds. We concluded that the biodegradable and elastic microspheres may be facilely produced from a green and sustainable process with potential applications in drug release and three-dimensional cell culture.

  7. Bacterial transformation and biodegradation processes simulation in horizontal subsurface flow constructed wetlands using CWM1-RETRASO.

    PubMed

    Llorens, Esther; Saaltink, Maarten W; Poch, Manel; García, Joan

    2011-01-01

    The performance and reliability of the CWM1-RETRASO model for simulating processes in horizontal subsurface flow constructed wetlands (HSSF CWs) and the relative contribution of different microbial reactions to organic matter (COD) removal in a HSSF CW treating urban wastewater were evaluated. Various different approaches with diverse influent configurations were simulated. According to the simulations, anaerobic processes were more widespread in the simulated wetland and contributed to a higher COD removal rate [72-79%] than anoxic [0-1%] and aerobic reactions [20-27%] did. In all the cases tested, the reaction that most contributed to COD removal was methanogenesis [58-73%]. All results provided by the model were in consonance with literature and experimental field observations, suggesting a good performance and reliability of CWM1-RETRASO. According to the good simulation predictions, CWM1-RETRASO is the first mechanistic model able to successfully simulate the processes described by the CWM1 model in HSSF CWs.

  8. Evolution of heavy metal speciation during the aerobic composting process of sewage sludge.

    PubMed

    Liu, Yangsheng; Ma, Lanlan; Li, Yaqiong; Zheng, Liting

    2007-03-01

    The contents of heavy metals and their bioavailability to the soil-plant system were the major limitation to the application of sewage sludge compost in soil. This study was conducted to determine the evolution of heavy metal speciation in the course of an aerobic composting, and investigate the influence of changes of composting process parameters including pH, temperature and organic matter (OM) content on distribution of heavy metal speciation in composted sludge. The sequential extraction procedure developed by Tessier et al. was used in sludge compost to determine the heavy metal speciation. Results showed that, during composting, (1) the contents of the residue fraction for Pb, Zn and Cd were decreased but those for Ni and Cr were increased; the Cu residue fraction was almost constant; (2) the contents of the total mobile fractions (including fractions 1-4) for Zn and Pb were significantly increased, but the increase of those for Cu and Ni were not so remarkable; (3) there were significant degrees of correlation between heavy metal fractions and changes of some selected parameters (for example, pH, composting temperature, and OM content). Only the content of the total mobile fractions for Cu could be predictable from its total content. For the prediction of the total mobile fractions of Zn, Ni, Cd and Cr, the R(2) value was significantly increased by the inclusion of other variables such as pH, temperature and OM content.

  9. Aerobic thermophilic treatment of sewage sludge at pilot plant scale. 2. Technical solutions and process design.

    PubMed

    Ponti, C; Sonnleitner, B; Fiechter, A

    1995-01-15

    The performance of the ATS process depends essentially on the oxygen transfer efficiency. Improvement of the mass transfer capacity of a bioreactor allowed to reduce the incubation time necessary to attain sludge stabilization. It is important to use equipment with a high aeration efficiency such as an injector aeration system. The ratio between the total oxygen consumption and the organic matter degradation (delta COD) ranged between 0.4 and 0.8 in the pilot plant, whereas 1.23 was found in completely mixed bioreactors (Bomio, 1990). No significant improvement of the bacterial degradation efficiency was attained with a specific power input exceeding 6-8 kW m-3. A mean residence time of less than 1 d allowed organic matter removals up to 40% with specific power consumption of 10 kWh kg-1 COD oxidized. The sludge hygienization is one of the objectives and benefits of the thermophilic treatment: not only temperature but also the total solids content were important factors affecting inactivation of pathogens. The inactivation rate was promoted by the increase of temperature, while the residual colony forming units decreased with reducing the total solids content of sewage sludge. It is concluded that continuous operation mode would not affect the quality of the hygienization but could display the high degradation potential of the aerobic system.

  10. Aerobic biodegradation of 2,4-DNT and 2,6-DNT: performance characteristics and biofilm composition changes in continuous packed-bed bioreactors.

    PubMed

    Paca, J; Halecky, M; Barta, J; Bajpai, R

    2009-04-30

    This manuscript deals with continuous experiments for biodegradation of individual dinitrotoluenes by a defined mixed culture in packed-bed reactors (PBRs) containing either poraver or fire-clay as packing material. Removal efficiencies and volumetric biodegradation rates were measured as a function of the loading rate of 2,4-dinitrotoluene (2,4-DNT) and 2,6-dinitrotoluene (2,6-DNT) under steady-state conditions. The poraver reactor showed higher removal efficiencies for both the DNTs. The removal efficiency for 2,4-DNT remained greater than 90% in the poraver reactor whereas it dropped steadily from 85 to 65% in the fire-clay reactor as the organic loading rates were increased from 19 to 60 mg L(-1)day(-1). Similar trends were seen for the volumetric degradation rate as well. In both the reactors, 2,4-DNT degraded more effectively than 2,6-DNT. The microbial consortium was characterized both in the inoculum as well as in the operating PBR. Cell numbers per gram dry packing material were similar in the two reactors. However, there was a distinct difference in the nature of microorganisms that were found in the two packings. The fire-clay contained a larger number of cells that were not primary degraders of DNTs.

  11. Comprehensive microbial analysis of combined mesophilic anaerobic-thermophilic aerobic process treating high-strength food wastewater.

    PubMed

    Jang, Hyun Min; Ha, Jeong Hyub; Park, Jong Moon; Kim, Mi-Sun; Sommer, Sven G

    2015-04-15

    A combined mesophilic anaerobic-thermophilic aerobic process was used to treat high-strength food wastewater in this study. During the experimental period, most of solid residue from the mesophilic anaerobic reactor (R1) was separated by centrifugation and introduced into the thermophilic aerobic reactor (R2) for further digestion. Then, thermophilic aerobically-digested sludge was reintroduced into R1 to enhance reactor performance. The combined process was operated with two different Runs: Run I with hydraulic retention time (HRT) = 40 d (corresponding OLR = 3.5 kg COD/m(3) d) and Run II with HRT = 20 d (corresponding OLR = 7 kg COD/m(3)). For a comparison, a single-stage mesophilic anaerobic reactor (R3) was operated concurrently with same OLRs and HRTs as the combined process. During the overall digestion, all reactors showed high stability without pH control. The combined process demonstrated significantly higher organic matter removal efficiencies (over 90%) of TS, VS and COD and methane production than did R3. Quantitative real-time PCR (qPCR) results indicated that higher populations of both bacteria and archaea were maintained in R1 than in R3. Pyrosequencing analysis revealed relatively high abundance of phylum Actinobacteria in both R1 and R2, and a predominance of phyla Synergistetes and Firmicutes in R3 during Run II. Furthermore, R1 and R2 shared genera (Prevotella, Aminobacterium, Geobacillus and Unclassified Actinobacteria), which suggests synergy between mesophilic anaerobic digestion and thermophilic aerobic digestion. For archaea, in R1 methanogenic archaea shifted from genus Methanosaeta to Methanosarcina, whereas genera Methanosaeta, Methanobacterium and Methanoculleus were predominant in R3. The results demonstrated dynamics of key microbial populations that were highly consistent with an enhanced reactor performance of the combined process.

  12. Role of nitrification in the biodegradation of selected artificial sweetening agents in biological wastewater treatment process.

    PubMed

    Tran, N H; Nguyen, V T; Urase, T; Ngo, H H

    2014-06-01

    The biodegradation of the six artificial sweetening agents including acesulfame (ACE), aspartame (ASP), cyclamate (CYC), neohesperidindihydrochalcone (NHDC), saccharin (SAC), and sucralose (SUC) by nitrifying activated sludge was first examined. Experimental results showed that ASP and NHDC were the most easily degradable compounds even in the control tests. CYC and SAC were efficiently biodegraded by the nitrifying activated sludge, whereas ACE and SUC were poorly removed. However, the biodegradation efficiencies of the ASs were increased with the increase in initial ammonium concentrations in the bioreactors. The association between nitrification and co-metabolic degradation was investigated and a linear relationship between nitrification rate and co-metabolic biodegradation rate was observed for the target artificial sweeteners (ASs). The contribution of heterotrophic microorganisms and autotrophic ammonia oxidizers in biodegradation of the ASs was elucidated, of which autotrophic ammonia oxidizers played an important role in the biodegradation of the ASs, particularly with regards to ACE and SUC.

  13. Aerobic Exercise for Reducing Migraine Burden: Mechanisms, Markers, and Models of Change Processes

    PubMed Central

    Irby, Megan B.; Bond, Dale S.; Lipton, Richard B.; Nicklas, Barbara; Houle, Timothy T.; Penzien, Donald B.

    2016-01-01

    Background Engagement in regular exercise routinely is recommended as an intervention for managing and preventing migraine, and yet empirical support is far from definitive. We possess at best a weak understanding of how aerobic exercise and resulting change in aerobic capacity influence migraine, let alone the optimal parameters for exercise regimens as migraine therapy (eg, who will benefit, when to prescribe, optimal types, and doses/intensities of exercise, level of anticipated benefit). These fundamental knowledge gaps critically limit our capacity to deploy exercise as an intervention for migraine. Overview Clear articulation of the markers and mechanisms through which aerobic exercise confers benefits for migraine would prove invaluable and could yield insights on migraine pathophysiology. Neurovascular and neuroinflammatory pathways, including an effect on obesity or adiposity, are obvious candidates for study given their role both in migraine as well as the changes known to accrue with regular exercise. In addition to these biological pathways, improvements in aerobic fitness and migraine alike also are mediated by changes in psychological and sociocognitive factors. Indeed a number of specific mechanisms and pathways likely are operational in the relationship between exercise and migraine improvement, and it remains to be established whether these pathways operate in parallel or synergistically. As heuristics that might conceptually benefit our research programs here forward, we: (1) provide an extensive listing of potential mechanisms and markers that could account for the effects of aerobic exercise on migraine and are worthy of empirical exploration and (2) present two exemplar conceptual models depicting pathways through which exercise may serve to reduce the burden of migraine. Conclusion Should the promise of aerobic exercise as a feasible and effective migraine therapy be realized, this line of endeavor stands to benefit migraineurs (including the

  14. Granular activated carbon for simultaneous adsorption and biodegradation of toxic oil sands process-affected water organic compounds.

    PubMed

    Islam, Md Shahinoor; Zhang, Yanyan; McPhedran, Kerry N; Liu, Yang; Gamal El-Din, Mohamed

    2015-04-01

    Naphthenic acids (NAs) released into oil sands process-affected water (OSPW) during bitumen processing in Northern Alberta are problematic for oil sands industries due to their toxicity in the environment and resistance to degradation during conventional wastewater treatment processes. Granular activated carbon (GAC) has shown to be an effective media in removing biopersistent organics from wastewater using a combination of adsorption and biodegradation removal mechanisms. A simultaneous GAC (0.4 g GAC/L) adsorption and biodegradation (combined treatment) study was used for the treatment of raw and ozonated OSPW. After 28 days of batch treatment, classical and oxidized NAs removals for raw OSPW were 93.3% and 73.7%, and for ozonated OSPW were 96.2% and 77.1%, respectively. Synergetic effects of the combined treatment process were observed in removals of COD, the acid extractable fraction, and oxidized NAs, which indicated enhanced biodegradation and bioregeneration in GAC biofilms. A bacteria copy number >10(8) copies/g GAC on GAC surfaces was found using quantitative real time polymerase chain reaction after treatment for both raw and ozonated OSPW. A Microtox(®) acute toxicity test (Vibrio fischeri) showed effective toxicity removal (>95.3%) for the combined treatments. Therefore, the simultaneous GAC adsorption and biodegradation treatment process is a promising technology for the elimination of toxic OSPW NAs.

  15. Biodegradable Polycaprolactone as Ion Solvating Polymer for Solution-Processed Light-Emitting Electrochemical Cells

    PubMed Central

    Jürgensen, Nils; Zimmermann, Johannes; Morfa, Anthony John; Hernandez-Sosa, Gerardo

    2016-01-01

    In this work, we demonstrate the use of the biodegradable polymer polycaprolactone (PCL) as the ion solvating polymer in solution-processed light-emitting electrochemical cells (LEC). We show that the inclusion of PCL in the active layer yields higher ionic conductivities and thus contributes to a rapid formation of the dynamic p-i-n junction and reduction of operating voltages. PCL shows no phase separation with the emitter polymer and reduces film roughness. The devices show light-emission at voltages as low as 3.2 V and lifetimes on the order of 30 h operating above 150 cd m−2 with turn-on times <20 s and current and luminous efficacies of 3.2 Cd A−1 and 1.5 lm W−1 respectively. PMID:27811991

  16. Biodegradable Polycaprolactone as Ion Solvating Polymer for Solution-Processed Light-Emitting Electrochemical Cells.

    PubMed

    Jürgensen, Nils; Zimmermann, Johannes; Morfa, Anthony John; Hernandez-Sosa, Gerardo

    2016-11-04

    In this work, we demonstrate the use of the biodegradable polymer polycaprolactone (PCL) as the ion solvating polymer in solution-processed light-emitting electrochemical cells (LEC). We show that the inclusion of PCL in the active layer yields higher ionic conductivities and thus contributes to a rapid formation of the dynamic p-i-n junction and reduction of operating voltages. PCL shows no phase separation with the emitter polymer and reduces film roughness. The devices show light-emission at voltages as low as 3.2 V and lifetimes on the order of 30 h operating above 150 cd m(-)(2) with turn-on times <20 s and current and luminous efficacies of 3.2 Cd A(-1) and 1.5 lm W(-1) respectively.

  17. Biodegradable Polycaprolactone as Ion Solvating Polymer for Solution-Processed Light-Emitting Electrochemical Cells

    NASA Astrophysics Data System (ADS)

    Jürgensen, Nils; Zimmermann, Johannes; Morfa, Anthony John; Hernandez-Sosa, Gerardo

    2016-11-01

    In this work, we demonstrate the use of the biodegradable polymer polycaprolactone (PCL) as the ion solvating polymer in solution-processed light-emitting electrochemical cells (LEC). We show that the inclusion of PCL in the active layer yields higher ionic conductivities and thus contributes to a rapid formation of the dynamic p-i-n junction and reduction of operating voltages. PCL shows no phase separation with the emitter polymer and reduces film roughness. The devices show light-emission at voltages as low as 3.2 V and lifetimes on the order of 30 h operating above 150 cd m‑2 with turn-on times <20 s and current and luminous efficacies of 3.2 Cd A‑1 and 1.5 lm W‑1 respectively.

  18. Evaluation of pre-treatment processes for increasing biodegradability of agro-food wastes.

    PubMed

    Hidalgo, D; Sastre, E; Gómez, M; Nieto, P

    2012-01-01

    Anaerobic digestion (AD) technology can be employed for treating sewage sludge, livestock waste or food waste. Generally, the hydrolysis stage is the rate-limiting step of the AD processes for solid waste degradation. Therefore, physical, chemical and biological pre-treatment methods or their combination are required, in order to reduce the rate of such a limiting step. In this study, four methods (mechanical shredding, acid hydrolysis, alkaline hydrolysis and sonication) were tested to improve methane production and anaerobic biodegradability of different agro-food wastes and their mixtures. The kinetics of anaerobic degradation and methane production ofpre-treated individual wastes and selected mixtures were investigated with batch tests. Sonication at lower frequencies (37 kHz) proved to give the best results with methane productivity enhancements of over 100% in the case of pig manure and in the range of 10-47% for the other wastes assayed. Furthermore, the ultimate methane production was proportional, in all the cases, to the specific energy input applied (Es). Sonication can, thus, enhance waste digestion and the rate and quantity of biogas generated. The behaviour of the other pre-treatments under the conditions assayed is not significant. Only a slight enhancement of biogas production (around 10%) was detected for whey and waste activated sludge (WAS) after mechanical shredding. The lack of effectiveness of chemical pre-treatments (acid and alkaline hydrolysis) can be justified by the inhibition of the methanogenic process due to the presence of high concentrations of sodium (up to 8 g l(-1) in some tests). Only in the case of WAS did the acid hydrolysis considerably increase the biodegradability of the sample (79%), because in this case no inhibition by sodium took place. Some hints of a synergistic effect have been observed when co-digestion of the mixtures was performed.

  19. The effect of advanced oxidation processes on leachate biodegradation in recycling lysimeters.

    PubMed

    Ledakowicz, Stanisław; Kaczorek, Katarzyna

    2004-06-01

    Landfill processes were simulated in laboratory-scale bioreactors--lysimeters. The changes in leachate characteristics as well as the influence of advanced oxidation processes (AOPs) on the processes taking place in the sanitary landfill were investigated. Lysimeters were filled with material simulating municipal waste in the city of Lodz, Poland. Compost in the amount of 30% w/w and the methanogens inoculum were added in order to enhance development of a methanogenic phase. The leachate produced in lysimeters was recirculated. In order to investigate the influence of AOPs implementation on processes taking place in landfills two runs in lysimeters were performed, each lasting about 250 days. The leachate composition and biogas composition and production changes showed trends that confirmed that the bench-scale lysimeters appeared suitable to simulate processes taking place in the landfill. The application of AOPs to the leachate recirculated into the lysimeters did not bring about unequivocally positive effects. The ozonation of the leachate, implemented at the beginning of the methanogenic phase, caused slight acceleration (about 2 weeks) of the biodegradation, whereas employment of H2O2/UV led to the inhibition of anaerobic processes.

  20. Enhanced performance of denitrifying sulfide removal process at high carbon to nitrogen ratios under micro-aerobic condition.

    PubMed

    Chen, Chuan; Zhang, Ruo-Chen; Xu, Xi-Jun; Fang, Ning; Wang, Ai-Jie; Ren, Nan-Qi; Lee, Duu-Jong

    2017-02-11

    The success of denitrifying sulfide removal (DSR) processes, which simultaneously degrade sulfide, nitrate and organic carbon in the same reactor, counts on synergetic growths of autotrophic and heterotrophic denitrifiers. Feeding wastewaters at high C/N ratio would stimulate overgrowth of heterotrophic bacteria in the DSR reactor so deteriorating the growth of autotrophic denitrifiers. The DSR tests at C/N=1.26:1, 2:1 or 3:1 and S/N =5:6 or 5:8 under anaerobic (control) or micro-aerobic conditions were conducted. Anaerobic DSR process has <50% sulfide removal with no elemental sulfur transformation. Under micro-aerobic condition to remove <5% sulfide by chemical oxidation pathway, 100% sulfide removal is achieved by the DSR consortia. Continuous-flow tests under micro-aerobic condition have 70% sulfide removal and 55% elemental sulfur recovery. Trace oxygen enhances activity of sulfide-oxidizing, nitrate-reducing bacteria to accommodate properly the wastewater with high C/N ratios.

  1. Rapid prototyping of biodegradable microneedle arrays by integrating CO2 laser processing and polymer molding

    NASA Astrophysics Data System (ADS)

    Tu, K. T.; Chung, C. K.

    2016-06-01

    An integrated technology of CO2 laser processing and polymer molding has been demonstrated for the rapid prototyping of biodegradable poly-lactic-co-glycolic acid (PLGA) microneedle arrays. Rapid and low-cost CO2 laser processing was used for the fabrication of a high-aspect-ratio microneedle master mold instead of conventional time-consuming and expensive photolithography and etching processes. It is crucial to use flexible polydimethylsiloxane (PDMS) to detach PLGA. However, the direct CO2 laser-ablated PDMS could generate poor surfaces with bulges, scorches, re-solidification and shrinkage. Here, we have combined the polymethyl methacrylate (PMMA) ablation and two-step PDMS casting process to form a PDMS female microneedle mold to eliminate the problem of direct ablation. A self-assembled monolayer polyethylene glycol was coated to prevent stiction between the two PDMS layers during the peeling-off step in the PDMS-to-PDMS replication. Then the PLGA microneedle array was successfully released by bending the second-cast PDMS mold with flexibility and hydrophobic property. The depth of the polymer microneedles can range from hundreds of micrometers to millimeters. It is linked to the PMMA pattern profile and can be adjusted by CO2 laser power and scanning speed. The proposed integration process is maskless, simple and low-cost for rapid prototyping with a reusable mold.

  2. Anaerobic-aerobic treatment of purified terephthalic acid (PTA) effluent; a techno-economic alternative to two-stage aerobic process.

    PubMed

    Pophali, G R; Khan, R; Dhodapkar, R S; Nandy, T; Devotta, S

    2007-12-01

    This paper addresses the treatment of purified terephthalic acid (PTA) effluent using anaerobic and aerobic processes. Laboratory studies were carried out on flow proportionate composite wastewater generated from the manufacturing of PTA. An activated sludge process (ASP-two stage and single stage) and an upflow anaerobic fixed film fixed bed reactor (AFFFBR) were used, individually and in combination. The performance of a full-scale ETP under existing operating conditions was also studied. Full scale ETP studies revealed that the treatment of PTA effluent using a two-stage ASP alone does not meet treated effluent quality within the prescribed Indian Standards. The biomass produced in the two stage ASP was very viscous and fluffy and the sludge volume index (SVI) was very high (200-450 ml/g). However, pretreatment of PTA effluent using an upflow AFFFBR ensured substantial reduction in BOD (63%) and COD (62%) with recovery of biogas at 1.8-1.96 l/l effluent treated at a volumetric loading rate (VLR) 4-5 kg COD/m(3) d. The methane content in the biogas varied between 55% and 60%. The pretreated effluent from the upflow AFFFBR was then treated through a single stage ASP. The biomass produced in the ASP after anaerobic treatment had very good settlability (SVI: 75-90 ml/g) as compared to the two stage ASP and the treated effluent quality with respect to BOD, COD and SS was within the prescribed Indian Standards. The alternative treatment process comprising an upflow AFFFBR and a single stage ASP ensured net power saving of 257 kW and in addition generated 442 kW of power through the AFFFBR.

  3. New insights into polyurethane biodegradation and realistic prospects for the development of a sustainable waste recycling process.

    PubMed

    Cregut, Mickael; Bedas, M; Durand, M-J; Thouand, G

    2013-12-01

    Polyurethanes are polymeric plastics that were first used as substitutes for traditional polymers suspected to release volatile organic hazardous substances. The limitless conformations and formulations of polyurethanes enabled their use in a wide variety of applications. Because approximately 10 Mt of polyurethanes is produced each year, environmental concern over their considerable contribution to landfill waste accumulation appeared in the 1990s. To date, no recycling processes allow for the efficient reuse of polyurethane waste due to their high resistance to (a)biotic disturbances. To find alternatives to systematic accumulation or incineration of polyurethanes, a bibliographic analysis was performed on major scientific advances in the polyurethane (bio)degradation field to identify opportunities for the development of new technologies to recondition this material. Until polymers exhibiting oxo- or hydro-biodegradative traits are generated, conventional polyurethanes that are known to be only slightly biodegradable are of great concern. The research focused on polyurethane biodegradation highlights recent attempts to reprocess conventional industrial polyurethanes via microbial or enzymatic degradation. This review describes several wonderful opportunities for the establishment of new processes for polyurethane recycling. Meeting these new challenges could lead to the development of sustainable management processes involving polymer recycling or reuse as environmentally safe options for industries. The ability to upgrade polyurethane wastes to chemical compounds with a higher added value would be especially attractive.

  4. Influence of biodegradation processes on the duration of CaCO3 as a pH buffer in municipal solid waste incinerator bottom ash.

    PubMed

    Johnson, C Annette; Furrer, Gerhard

    2002-01-15

    The long-term leachability of heavy metals from municipal solid waste incinerator (MSWI) bottom ash is of concern because of its potential use as a secondary construction material. Calcite is the most important long-term buffer in MSWI bottom ash as it buffers solutions during percolation and is an important factor in the control of heavy-metal mobility. It has been argued that biodegradation of residual organic material in the MSWI is a significant source of acidity. Model calculations have therefore been carried out to determine the influence of biodegradation on the longevity of the calcite buffer. Using the program STEADYQL, which couples thermodynamic equilibrium with kinetically controlled reactions, solution composition was estimated at steady state. The concentration of Ca dissolved from calcite was estimated in the presence and absence of gypsum as a function of the reaction rate of a number of slow reactions: aerobic, ferrogenic, sulfogenic, and methanogenic biodegradation; diffusion of O2 into the system; degassing of CO2 out of the system; and dissolution of Ca silicate. It was found that, independent of the rate, the biodegradation of organic matter had little influence on the longevity of the calcite buffer (between 2,000 and 3,000 yr for a deposit of 1 m in depth), that anaerobic biodegradation may have a slight retarding effect, and that calcite dissolution due to acid input via precipitation was negligible (around 3% of the total at reference conditions for rainwater with a pH value of 4.3).

  5. Biodegradation Processes in a Laboratory-Scale Groundwater Contaminant Plume Assessed by Fluorescence Imaging and Microbial Analysis▿

    PubMed Central

    Rees, Helen C.; Oswald, Sascha E.; Banwart, Steven A.; Pickup, Roger W.; Lerner, David N.

    2007-01-01

    Flow reactors containing quartz sand colonized with biofilm were set up as physical model aquifers to allow degrading plumes of acetate or phenol to be formed from a point source. A noninvasive fluorescent tracer technique was combined with chemical and biological sampling in order to quantify transport and biodegradation processes. Chemical analysis of samples showed a substantial decrease in carbon concentration between the injection and outflow resulting primarily from dilution but also from biodegradation. Two-dimensional imaging of the aqueous oxygen [O2(aq)] concentration field quantified the depletion of O2(aq) within the contaminant plume and provided evidence for microbial respiration associated with biodegradation of the carbon source. Combined microbiological, chemical, and O2(aq) imaging data indicated that biodegradation was greatest at the plume fringe. DNA profiles of bacterial communities were assessed by temperature gradient gel electrophoresis, which revealed that diversity was limited and that community changes observed depended on the carbon source used. Spatial variation in activity within the plume could be quantitatively accounted for by the changes observed in active cell numbers rather than differences in community structure, the total biomass present, or the increased enzyme activity of individual cells. Numerical simulations and comparisons with the experimental data were used to test conceptual models of plume processes. Results demonstrated that plume behavior was best described by growth and decay of active biomass as a single functional group of organisms represented by active cell counts. PMID:17468279

  6. Aerobic treatability of waste effluent from the leather finishing industry. Master's thesis

    SciTech Connect

    Vinger, J.A.

    1993-12-01

    The Seton Company supplies finished leather products exclusively for the automotive industry. In the process of finishing leather, two types of wastewaters are generated. The majority of the wastewater is composed of water-based paint residuals while the remainder is composed of solvent-based coating residuals. Aerobic treatability studies were conducted using water-based and solvent-based waste recirculatory waters from the Seton Company's Saxton, Pennsylvania processing plant. The specific objective was to determine the potential for using aerobic biological processes to biodegrade the industry's wastes and determine the potential for joint treatment at the local publicly owned treatment works (POTW). This study was accomplished in two phases. Phase I was conducted during the Spring Semester 1993 and consisted of aerobic respirometer tests of the raw wastes and mass balance analysis. The results of Phase I were published in a report to the Seton Company as Environmental Resources Research Institute project number 92C.II40R-1. Phase II was conducted during the Summer Semester 1993 and consisted of bench-scale reactor tests and additional aerobic respirometer tests. The aerobic respirometer batch tests and bench-scale reactor tests were used to assess the treatability of solvent-based and water-based wastewaters and determine the degree of biodegradability of the wastewaters. Mass balance calculations were made using measured characteristics.

  7. Optimization of hydraulic shear parameters and reactor configuration in the aerobic granular sludge process.

    PubMed

    Zhu, Liang; Zhou, Jiaheng; Yu, Haitian; Xu, Xiangyang

    2015-01-01

    The hydraulic shear acts as an important selection pressure in aerobic sludge granulation. The effects of the hydraulic shear rate and reactor configuration on structural characteristics of aerobic granule in view of the hydromechanics. The hydraulic shear analysis was proposed to overcome the limitation of using superficial gas velocity (SGV) to express the hydraulic shear stress. Results showed that the stronger hydraulic shear stress with SGV above 2.4 cm s(-1) promoted the microbial aggregation, and favoured the structural stability of the granular sludge. According to the hydraulic shear analysis, the total shear rate reached (0.56-2.31)×10(5) s(-1) in the granular reactor with a larger ratio of height to diameter (H/D), and was higher than that in the reactor with smaller H/D, where the sequencing airlift bioreactor with smaller H/D had a high total shear rate under the same SGV. Results demonstrated that the granular reactor could provide a stronger hydraulic shear stress which promotes the formation and structural stability of aerobic granules.

  8. Anaerobic biodegradation of surrogate naphthenic acids.

    PubMed

    Clothier, Lindsay N; Gieg, Lisa M

    2016-03-01

    Surface bitumen extraction from the Alberta's oil sands region generates large settling basins known as tailings ponds. The oil sands process-affected water (OSPW) stored in these ponds contain solid and residual bitumen-associated compounds including naphthenic acids (NAs) that can potentially be biodedgraded by indigenous tailings microorganisms. While the biodegradation of some NAs is known to occur under aerobic conditions, little is understood about anaerobic NA biodegradation even though tailings ponds are mainly anoxic. Here, we investigated the potential for anaerobic NA biodegradation by indigenous tailings microorganisms. Enrichment cultures were established from anoxic tailings that were amended with 5 single-ringed surrogate NAs or acid-extractable organics (AEO) from OSPW and incubated under nitrate-, sulfate-, iron-reducing, and methanogenic conditions. Surrogate NA depletion was observed under all anaerobic conditions tested to varying extents, correlating to losses in the respective electron acceptor (sulfate or nitrate) or the production of predicted products (Fe(II) or methane). Tailings-containing cultures incubated under the different electron-accepting conditions resulted in the enrichment and putative identification of microbial community members that may function in metabolizing surrogate NAs under the various anoxic conditions. In addition, more complex NAs (in the form of AEO) was observed to drive sulfate and iron reduction relative to controls. Overall, this study has shown that simple surrogate NAs can be biodegraded under a variety of anoxic conditions, a key first step in understanding the potential anaerobic metabolism of NAs in oil sands tailings ponds and other industrial wastewaters.

  9. A New Efficient Hybrid Intelligent Model for Biodegradation Process of DMP with Fuzzy Wavelet Neural Networks

    NASA Astrophysics Data System (ADS)

    Huang, Mingzhi; Zhang, Tao; Ruan, Jujun; Chen, Xiaohong

    2017-01-01

    A new efficient hybrid intelligent approach based on fuzzy wavelet neural network (FWNN) was proposed for effectively modeling and simulating biodegradation process of Dimethyl phthalate (DMP) in an anaerobic/anoxic/oxic (AAO) wastewater treatment process. With the self learning and memory abilities of neural networks (NN), handling uncertainty capacity of fuzzy logic (FL), analyzing local details superiority of wavelet transform (WT) and global search of genetic algorithm (GA), the proposed hybrid intelligent model can extract the dynamic behavior and complex interrelationships from various water quality variables. For finding the optimal values for parameters of the proposed FWNN, a hybrid learning algorithm integrating an improved genetic optimization and gradient descent algorithm is employed. The results show, compared with NN model (optimized by GA) and kinetic model, the proposed FWNN model have the quicker convergence speed, the higher prediction performance, and smaller RMSE (0.080), MSE (0.0064), MAPE (1.8158) and higher R2 (0.9851) values. which illustrates FWNN model simulates effluent DMP more accurately than the mechanism model.

  10. A New Efficient Hybrid Intelligent Model for Biodegradation Process of DMP with Fuzzy Wavelet Neural Networks

    PubMed Central

    Huang, Mingzhi; Zhang, Tao; Ruan, Jujun; Chen, Xiaohong

    2017-01-01

    A new efficient hybrid intelligent approach based on fuzzy wavelet neural network (FWNN) was proposed for effectively modeling and simulating biodegradation process of Dimethyl phthalate (DMP) in an anaerobic/anoxic/oxic (AAO) wastewater treatment process. With the self learning and memory abilities of neural networks (NN), handling uncertainty capacity of fuzzy logic (FL), analyzing local details superiority of wavelet transform (WT) and global search of genetic algorithm (GA), the proposed hybrid intelligent model can extract the dynamic behavior and complex interrelationships from various water quality variables. For finding the optimal values for parameters of the proposed FWNN, a hybrid learning algorithm integrating an improved genetic optimization and gradient descent algorithm is employed. The results show, compared with NN model (optimized by GA) and kinetic model, the proposed FWNN model have the quicker convergence speed, the higher prediction performance, and smaller RMSE (0.080), MSE (0.0064), MAPE (1.8158) and higher R2 (0.9851) values. which illustrates FWNN model simulates effluent DMP more accurately than the mechanism model. PMID:28120889

  11. Modeling intrinsic bioremediation for interpret observable biogeochemical footprints of BTEX biodegradation: the need for fermentation and abiotic chemical processes.

    PubMed

    Maurer, Max; Rittmann, Bruce E

    2004-12-01

    The intrinsic bioremediation of BTEX must be documented by the stoichiometric consumption and production of several other compounds, called 'footprints' of the biodegradation reaction. Although footprints of BTEX biodegradation are easy to identify from reaction stoichiometry, they can be confounded by the stepwise nature of the biodegradation reactions and by several abiotic chemical reactions that also produce or consume the footprints. In order to track the footprints for BTEX biodegradation, the following reactions need to be considered explicitly: (1) fermentation and methanogenesis as separate processes, (2) precipitation and dissolution of calcite, (3) precipitation and dissolution of amorphous iron monosulfide (FeS), (4) conversion of FeS into the thermodynamically stable pyrite (FeS2) with loss of sulfide and abiotic formation of H2, and (5) reductive dissolution of solid iron(III) by oxidation of sulfide. We critically review the research that underlies why these mechanisms must be included and how to describe them quantitatively. A companion manuscript develops and applies a mathematical model that includes these reactions.

  12. Removal of the surfactant sodium dodecylbenzenesulfonate from water by processes based on adsorption/bioadsorption and biodegradation.

    PubMed

    Bautista-Toledo, María Isidora; Rivera-Utrilla, José; Méndez-Díaz, José Diego; Sánchez-Polo, Manuel; Carrasco-Marín, Francisco

    2014-03-15

    This study analyzed the bioadsorption/biodegradation kinetics of the surfactant sodium dodecylbenzenesulfonate (SDBS) on commercial activated carbons and on activated carbons prepared in the laboratory by activation of almond shells. The effect of surface oxygen species on these processes was also investigated by using an activated carbon from almond shells oxidized with H2O2 or HNO3. SDBS removal kinetics followed a first-order kinetic model, with rate constants between 1.25×10(-2) h(-1) and 2.14×10(-2) h(-1). The removal rate constants of total organic carbon (TOC) were also determined, obtaining values ranging between 0.51×10(-2) h(-1) and 1.76×10(-2) h(-1). TOC removal rate constants were lower than SDBS removal rate constants, demonstrating that SDBS is also biodegraded during bioadsorption. Both the inorganic carbon concentration and the colony forming units confirm this biodegradation. The amount of SDBS removed from water varies between 109.0 and 232.3 mg SDBS/g of carbon. When SDBS adsorption on activated carbon is conducted in the presence of bacteria, which is the real situation in water treatment plants, a fraction of bacteria are adsorbed on the surface of activated carbon. A part of the SDBS is removed by adsorption (bioadsorption) and other part by biodegradation.

  13. Biodegradability of Plastics

    PubMed Central

    Tokiwa, Yutaka; Calabia, Buenaventurada P.; Ugwu, Charles U.; Aiba, Seiichi

    2009-01-01

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed. PMID:19865515

  14. Biodegradability of plastics.

    PubMed

    Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

    2009-08-26

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  15. Anaerobic biodegradation of (emerging) organic contaminants in the aquatic environment.

    PubMed

    Ghattas, Ann-Kathrin; Fischer, Ferdinand; Wick, Arne; Ternes, Thomas A

    2017-02-03

    Although strictly anaerobic conditions prevail in several environmental compartments, up to now, biodegradation studies with emerging organic contaminants (EOCs), such as pharmaceuticals and personal care products, have mainly focused on aerobic conditions. One of the reasons probably is the assumption that the aerobic degradation is more energetically favorable than degradation under strictly anaerobic conditions. Certain aerobically recalcitrant contaminants, however, are biodegraded under strictly anaerobic conditions and little is known about the organisms and enzymatic processes involved in their degradation. This review provides a comprehensive survey of characteristic anaerobic biotransformation reactions for a variety of well-studied, structurally rather simple contaminants (SMOCs) bearing one or a few different functional groups/structural moieties. Furthermore it summarizes anaerobic degradation studies of more complex contaminants with several functional groups (CMCs), in soil, sediment and wastewater treatment. While strictly anaerobic conditions are able to promote the transformation of several aerobically persistent contaminants, the variety of observed reactions is limited, with reductive dehalogenations and the cleavage of ether bonds being the most prevalent. Thus, it becomes clear that the transferability of degradation mechanisms deduced from culture studies of SMOCs to predict the degradation of CMCs, such as EOCs, in environmental matrices is hampered due the more complex chemical structure bearing different functional groups, different environmental conditions (e.g. matrix, redox, pH), the microbial community (e.g. adaptation, competition) and the low concentrations typical for EOCs.

  16. Climatic thresholds for pedogenic iron oxides under aerobic conditions: Processes and their significance in paleoclimate reconstruction

    NASA Astrophysics Data System (ADS)

    Long, Xiaoyong; Ji, Junfeng; Barrón, Vidal; Torrent, José

    2016-10-01

    Iron oxides are widely distributed across the surface of the Earth as a result of the aerobic weathering of primary Fe-bearing minerals. Pedogenic iron oxides which consist mainly of hematite (Hm), goethite (Gt), maghemite (Mgh), are often concentrated synchronously in aerobic soils under low to moderate rainfall regimes. Magnetic susceptibility (χ) and redness, which respectively reflect the content of Mgh and Hm in soils, are considered reasonable pedogenic and climatic indicators in soil taxonomy and paleorainfall reconstruction. However, under high rainfall regimes, the grain growth of Mgh and transformation to Hm, combined with the prior formation of Gt under conditions of high relative humidity (RH), can result in magnetic reduction and dramatic yellowing of soils and sediments, which explains the existence of rainfall thresholds for Mgh and Hm at a large scale even before the pedogenic environment turns anaerobic. In order to capture the rainfall thresholds for Mgh and Hm occurring under aerobic conditions, we explored a tropical transect across a granitic region where the soil color turned from red to yellow under a wide rainfall range of 900-2200 mm/yr and a corresponding mean annual RH range of 77%-85%. We observed a lower rainfall threshold of ∼1500 mm/yr and a corresponding RH ∼80% for Mgh and Hm along this transect, as well as a higher rainfall threshold of ∼1700 mm/yr and a corresponding RH of ∼81% for Gt and total pedogenic iron oxides (citrate/bicarbonate/dithionite-extractable Fe, Fed). Cross-referencing with comparable studies in temperate and subtropical regions, we noted that the rainfall or RH thresholds for Fed and Hm or Mgh likewise increase with temperature. Moreover, the different thresholds for total and individual iron oxide phase indicates that a negative correlation between chemical weathering intensity and redness or χ in sediment sequences can occur under the prevalent climate regime just between their thresholds. Finally

  17. Processing and characterization of solid and microcellular biobased and biodegradable PHBV-based polymer blends and composites

    NASA Astrophysics Data System (ADS)

    Javadi, Alireza

    Petroleum-based polymers have made a significant contribution to human society due to their extraordinary adaptability and processability. However, due to the wide-spread application of plastics over the past few decades, there are growing concerns over depleting fossil resources and the undesirable environmental impact of plastics. Most of the petroleum-based plastics are non-biodegradable and thus will be disposed in landfills. Inappropriate disposal of plastics may also become a potential threat to the environment. Many approaches, such as efficient plastics waste management and replacing petroleum-based plastics with biodegradable materials obtained from renewable resources, have been put forth to overcome these problems. Plastics waste management is at its beginning stages of development which is also more expensive than expected. Thus, there is a growing interest in developing sustainable biobased and biodegradable materials produced from renewable resources such as plants and crops, which can offer comparable performance with additional advantages, such as biodegradability, biocompatibility, and reducing the carbon footprint. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is one of the most promising biobased and biodegradable polymers, In fact many petroleum based polymers such as poly(propylene) (PP) can be potentially replaced by PHBV because of the similarity in their properties. Despite PHBV's attractive properties, there are many drawbacks such as high cost, brittleness, and thermal instability, which hamper the widespread usage of this specific polymer. The goals of this study are to investigate various strategies to address these drawbacks, including blending with other biodegradable polymers such as poly (butylene adipate-coterephthalate) (PBAT) or fillers (e.g., coir fiber, recycled wood fiber, and nanofillers) and use of novel processing technologies such as microcellular injection molding technique. Microcellular injection molding technique

  18. Degradation of enoxacin antibiotic by the electro-Fenton process: Optimization, biodegradability improvement and degradation mechanism.

    PubMed

    Annabi, Cyrine; Fourcade, Florence; Soutrel, Isabelle; Geneste, Florence; Floner, Didier; Bellakhal, Nizar; Amrane, Abdeltif

    2016-01-01

    This study aims to investigate the effectiveness of the electro-Fenton process on the removal of a second generation of fluoroquinolone, enoxacin. The electrochemical reactor involved a carbon-felt cathode and a platinum anode. The influence of some experimental parameters, namely the initial enoxacin concentration, the applied current intensity and the Fe(II) amount, was examined. The degradation of the target molecule was accompanied by an increase of the biodegradability, assessed from the BOD5 on COD ratio, which increased from 0 before treatment until 0.5 after 180 min of electrolysis at 50 mg L(-1) initial enoxacin concentration, 0.2 mmol L(-1) Fe(II) concentration and 300 mA applied current intensity. TOC and COD time-courses were also evaluated during electrolysis and reached maximum residual yields of 54% and 43% after 120 min of treatment, respectively. Moreover, a simultaneous generation of inorganic ions (fluorides, ammonium and nitrates) were observed and 3 short chain carboxylic acids (formic, acetic and oxalic acids) were identified and monitored during 180 min of electrolysis. By-products were identified according to UPLC-MS/MS results and a degradation pathway was proposed.

  19. Remediation of phenanthrene-contaminated soil by simultaneous persulfate chemical oxidation and biodegradation processes.

    PubMed

    Mora, Verónica C; Madueño, Laura; Peluffo, Marina; Rosso, Janina A; Del Panno, María T; Morelli, Irma S

    2014-06-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds with carcinogenic and/or mutagenic potential. To address the limitations of individual remediation techniques and to achieve better PAH removal efficiencies, the combination of chemical and biological treatments can be used. The degradation of phenanthrene (chosen as a model of PAH) by persulfate in freshly contaminated soil microcosms was studied to assess its impact on the biodegradation process and on soil properties. Soil microcosms contaminated with 140 mg/kgDRY SOIL of phenanthrene were treated with different persulfate (PS) concentrations 0.86-41.7 g/kgDRY SOIL and incubated for 28 days. Analyses of phenanthrene and persulfate concentrations and soil pH were performed. Cultivable heterotrophic bacterial count was carried out after 28 days of treatment. Genetic diversity analysis of the soil microcosm bacterial community was performed by PCR amplification of bacterial 16S rDNA fragments followed by denaturing gradient gel electrophoresis (DGGE). The addition of PS in low concentrations could be an interesting biostimulatory strategy that managed to shorten the lag phase of the phenanthrene biological elimination, without negative effects on the physicochemical and biological soil properties, improving the remediation treatment.

  20. Evaluation of biodegradability and oxidation degree of hospital wastewater using photo-Fenton process as the pretreatment method.

    PubMed

    Kajitvichyanukul, Puangrat; Suntronvipart, Nattapol

    2006-11-16

    In this work, the photo-Fenton process was used for the pretreatment of hospital wastewater with the objective of improving its overall biodegradability and determining the degree of increased oxidation. The chemical oxygen demand (COD), 5-day biochemical oxygen demand (BOD5), total organic carbon (TOC) and toxicity towards the gram negative marine bioluminescent bacteria of the species V. fischeri were selected as the environmental sum parameters to follow the performance of this process. The enhancement of biodegradability, evaluated in terms of the BOD5/COD ratio, increased from 0.3 to 0.52 and the oxidation degree, calculated in terms of AOS, leveled up from -1.14 to +1.58 at the optimum conditions; a dosage ratio of COD:H2O2:Fe(II) at 1:4:0.1, and a reaction pH of 3. The reduction in the inhibition percentage from the toxicity test indicated the safe levels for micro-organisms in degrading the residual organic substance in this method. Almost total removal percentages of COD, BOD5, and TOC were found by a sequential activated sludge process for the pre-treated wastewater. Results obtained from this work indicated that the photo-Fenton process could be a suitable pretreatment method in reducing toxicity of pollutants and enhancing biodegradability of hospital wastewaters treated in a coupled photochemical-biological system.

  1. Use of potassium dihydrogen phosphate and sawdust as adsorbents of ammoniacal nitrogen in aerobic composting process.

    PubMed

    Hu, Tian-Jue; Zeng, Guang-Ming; Huang, Dan-Lian; Yu, Hong-Yan; Jiang, Xiao-Yun; Dai, Fang; Huang, Guo-He

    2007-03-22

    Three kinds of adsorbents-potassium dihydrogen phosphate, sawdust and mixture of potassium dihydrogen phosphate and sawdust were added respectively into composting to investigate their adsorption effect on ammonia. The experimental results showed that all the adsorbents could restrain ammonia volatilizing, with the sorption of potassium dihydrogen phosphate adsorbents being the best of all, the sorption of mixture adsorbent with potassium dihydrogen phosphate and sawdust being the second and the sorption of sawdust adsorbent being the last. Therefore, the total nitrogen loss ratios respectively reduced from 38% to 13%, 15% and 21% after adding these three kinds of adsorbents into composting. However, potassium dihydrogen phosphate produced negative influence on composting properties as its supplemented amount exceeded a quantity basis equivalent to 18% of total nitrogen in the composting, for example: pH value had been lessened, microorganism activity reduced, which finally resulted in the reduction of biodegradation ratio of organic matter. But it did not result in these problems when using the mixture of potassium dihydrogen phosphate and sawdust as adsorbent, in which the amount of potassium dihydrogen phosphate was under a quantity basis equivalent to 6% of total nitrogen in the composting. Moreover, the mixture adsorbent produced better adsorption effect on ammonia, and raised biodegradation ratio of organic matter from 26% to 33%.

  2. Sequential reductive and oxidative biodegradation of chloroethenes stimulated in a coupled bioelectro-process.

    PubMed

    Lohner, Svenja T; Becker, Dirk; Mangold, Klaus-Michael; Tiehm, Andreas

    2011-08-01

    This article for the first time demonstrates successful application of electrochemical processes to stimulate sequential reductive/oxidative microbial degradation of perchloroethene (PCE) in mineral medium and in contaminated groundwater. In a flow-through column system, hydrogen generation at the cathode supported reductive dechlorination of PCE to cis-dichloroethene (cDCE), vinyl chloride (VC), and ethene (ETH). Electrolytically generated oxygen at the anode allowed subsequent oxidative degradation of the lower chlorinated metabolites. Aerobic cometabolic degradation of cDCE proved to be the bottleneck for complete metabolite elimination. Total removal of chloroethenes was demonstrated for a PCE load of approximately 1.5 μmol/d. In mineral medium, long-term operation with stainless steel electrodes was demonstrated for more than 300 days. In contaminated groundwater, corrosion of the stainless steel anode occurred, whereas DSA (dimensionally stable anodes) proved to be stable. Precipitation of calcareous deposits was observed at the cathode, resulting in a higher voltage demand and reduced dechlorination activity. With DSA and groundwater from a contaminated site, complete degradation of chloroethenes in groundwater was obtained for two months thus demonstrating the feasibility of the sequential bioelectro-approach for field application.

  3. Isotope biogeochemical assessment of natural biodegradation processes in open cast pit mining landscapes

    NASA Astrophysics Data System (ADS)

    Jeschke, Christina; Knöller, Kay; Koschorreck, Matthias; Ussath, Maria; Hoth, Nils

    2014-05-01

    In Germany, a major share of the energy production is based on the burning of lignite from open cast pit mines. The remediation and re-cultivation of the former mining areas in the Lusatian and Central German lignite mining district is an enormous technical and economical challenge. After mine closures, the surrounding landscapes are threatened by acid mine drainage (AMD), i.e. the acidification and mineralization of rising groundwater with metals and inorganic contaminants. The high content of sulfur (sulfuric acid, sulfate), nitrogen (ammonium) and iron compounds (iron-hydroxides) deteriorates the groundwater quality and decelerates sustainable development of tourism in (former) mining landscapes. Natural biodegradation or attenuation (NA) processes of inorganic contaminants are considered to be a technically low impact and an economically beneficial solution. The investigations of the stable isotope compositions of compounds involved in NA processes helps clarify the dynamics of natural degradation and provides specific informations on retention processes of sulfate and nitrogen-compounds in mine dump water, mine dump sediment, and residual pit lakes. In an active mine dump we investigated zones where the process of bacterial sulfate reduction, as one very important NA process, takes place and how NA can be enhanced by injecting reactive substrates. Stable isotopes signatures of sulfur and nitrogen components were examined and evaluated in concert with hydrogeochemical data. In addition, we delineated the sources of ammonium pollution in mine dump sediments and investigated nitrification by 15N-labeling techniques to calculate the limit of the conversion of harmful ammonium to nitrate in residual mining lakes. Ultimately, we provided an isotope biogeochemical assessment of natural attenuation of sulfate and ammonium at mine dump sites and mining lakes. Also, we estimated the risk potential for water in different compartments of the hydrological system. In

  4. Seasonal and wastewater stream variation of trace organic compounds in a dairy processing plant aerobic bioreactor.

    PubMed

    Heaven, Michael W; Wild, Karl; Verheyen, Vincent; Cruickshank, Alicia; Watkins, Mark; Nash, David

    2011-09-01

    Bioreactors are often an integral part of dairy factory efforts to reduce the biological oxygen demand of their wastewater. In this study, infeed, mixed liquor and supernatant samples of an aerobic bioreactor used by a dairy factory in South-Eastern Australia were analyzed for nutrients and organic compounds using gas chromatography-mass spectrometry and physicochemical analyses. Despite different concentrations of organic inputs into the bioreactor, nutrients and trace organic compounds were reduced significantly (i.e. average concentration of trace organic compounds: infeed=1681 μg/L; mixed liquor=257 μg/L; supernatant=23 μg/L). However, during one sampling period the bioreactor was adversely affected by the organic loading. Trace organic compounds in the samples were predominantly fatty acids associated with animal products. The analyses suggest that it is possible to trace a disruptive input (i.e. infeed with high organic carbon concentrations) into an aerobic bioreactor by measuring concentrations of fatty acids or ammonia.

  5. Aerobic degradation of BDE-209 by Enterococcus casseliflavus: Isolation, identification and cell changes during degradation process.

    PubMed

    Tang, Shaoyu; Yin, Hua; Chen, Shuona; Peng, Hui; Chang, Jingjing; Liu, Zehua; Dang, Zhi

    2016-05-05

    Decabromodiphenyl ether (BDE-209) is one of the most commonly used brominated flame retardants that have contaminated the environment worldwide. Microbial bioremediation has been considered as an effective technique to remove these sorts of persistent organic pollutants. Enterococcus casseliflavus, a gram-positive bacterium capable of aerobically transforming BDE-209, was isolated by our team from sediments in Guiyu, an e-waste dismantling area in Guangdong Province, China. To promote microbial bioremediation of BDE-209 and elucidate the mechanism behind its aerobic degradation, the effects of BDE-209 on the cell changes of E. casseliflavus were examined in this study. The experimental results demonstrated that the high cell surface hydrophobicity (CSH) of E. casseliflavus made the bacteria absorb hydrophobic BDE-209 more easily. E. casseliflavus responded to BDE-209 stress, resulting in an increase in cell membrane permeability and accumulation of BDE-209 inside the cell. The differential expression of intracellular protein was analyzed through two-dimensional gel electrophoresis (2-DE). More than 50 differentially expressed protein spots were reproducibly detected, including 25 up, and 25 down regulated after a 4 days exposure. Moreover, the apoptotic-like cell changes were observed during E. casseliflavus mediated degradation of BDE-209 by means of flow cytometry.

  6. Evaluating the primary and ready biodegradability of dianilinodithiophosphoric acid.

    PubMed

    Lin, Weixiong; Sun, Shuiyu; Xu, Pingting; Dai, Yongkang; Ren, Jie

    2016-04-01

    Dianilinodithiophosphoric acid (DDA) is widely used as sulfide mineral flotation collector in China. It is necessary to investigate the biodegradability of DDA to provide the fundamental knowledge to assess the environmental fate in the risk assessment of DDA and to design and operate the DDA flotation wastewater biological treatment plant. In the present study, the primary and ready aerobic biodegradations of DDA were studied and the primary biodegradation kinetic model of DDA was developed. The results show that DDA displays a good primary biodegradability and its biodegradation ratio reaches 99.8 % in 7 days. In contrast, DDA is not easily ready biodegradable; hence, it is a partially biodegradable organic compound. The primary aerobic biodegradation kinetics can be described using the first-order reaction kinetics equation: C = 19.72191e(-0.01513t).

  7. Biodegradation of a surrogate naphthenic acid under denitrifying conditions.

    PubMed

    Gunawan, Yetty; Nemati, Mehdi; Dalai, Ajay

    2014-03-15

    Extraction of bitumen from the shallow oil sands generates extremely large volumes of waters contaminated by naphthenic acid which pose severe environmental and ecological risks. Aerobic biodegradation of NA in properly designed bioreactors has been investigated in our earlier works. In the present work, anoxic biodegradation of trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA) coupled to denitrification was investigated as a potential ex situ approach for the treatment of oil sand process waters in bioreactors whereby excessive aeration cost could be eliminated, or as an in situ alternative for the treatment of these waters in anoxic stabilization ponds amended with nitrate. Using batch and continuous reactors (CSTR and biofilm), effects of NA concentration (100-750mgL(-1)), NA loading rate (up to 2607.9mgL(-1)h(-1)) and temperature (10-35°C) on biodegradation and denitrification processes were evaluated. In the batch system biodegradation of trans-4MCHCA coupled to denitrification occurred even at the highest concentration of 750mgL(-1). Consistent with the patterns reported for aerobic biodegradation, increase in initial concentration of NA led to higher biodegradation and denitrification rates and the optimum temperature was determined as 23-24°C. In the CSTR, NA removal and nitrate reduction rates passed through a maximum due to increases in NA loading rate. NA loading rate of 157.8mgL(-1)h(-1) at which maximum anoxic NA and nitrate removal rates (105.3mgL(-1)h(-1) and 144.5mgL(-1)h(-1), respectively) occurred was much higher than those reported for the aerobic alternative (NA loading and removal rates: 14.2 and 9.6mgL(-1)h(-1), respectively). In the anoxic biofilm reactor removal rates of NA and nitrate were dependent on NA loading rate in a linear fashion for the entire range of applied loading rates. The highest loading and removal rates for NA were 2607.9 and 2028.1mgL(-1)h(-1), respectively which were at least twofold higher than the values

  8. Characterization of biodegradation intermediates of nonionic surfactants by MALDI-MS. 2. Oxidative biodegradation profiles of uniform octylphenol polyethoxylate in 18O-labeled water.

    PubMed

    Sato, Hiroaki; Shibata, Atsushi; Wang, Yang; Yoshikawa, Hiromichi; Tamura, Hiroto

    2003-01-01

    This paper reports the characterization of the biodegradation intermediates of octylphenol octaethoxylate (OP(8)EO) by means of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The biodegradation test study was carried out in a pure culture (Pseudomonas putida S-5) under aerobic conditions using OP(8)EO as the sole carbon source and (18)O-labeled water as an incubation medium. In the MALDI-MS spectra of biodegraded samples, a series of OP(n)EO molecules with n = 2-8 EO units and their corresponding carboxylic acid products (OP(n)EC) were observed. The use of purified OP(8)EO enabled one to distinguish the shortened OPEO molecules as biodegradation intermediates. Furthermore, the formation of OP(8)EC (the oxidized product of OP(8)EO) supported the notion that terminal oxidation is a step in the biodegradation process. When biodegradation study was carried out in (18)O-labeled water, incorporation of (18)O atoms into the carboxyl group was observed for OPEC, while no incorporation was observed for the shortened OPEO products. These results could provide some rationale to the biodegradation mechanism of alkylphenol polyethoxylates.

  9. Simultaneous adsorption and biodegradation processes in sequencing batch reactor (SBR) for treating copper and cadmium-containing wastewater.

    PubMed

    Lim, Poh-Eng; Ong, Soon-An; Seng, Chye-Eng

    2002-02-01

    The application of simultaneous adsorption and biodegradation processes in the same reactor is known to be effective in the removal of both biodegradable and non-biodegradable contaminants in various kinds of wastewater. The objective of this study is to evaluate the efficacy of the two processes under sequencing batch reactor (SBR) operation in treating copper and cadmium-containing synthetic wastewater with powdered activated carbon (PAC) as the adsorbent. The SBR systems were operated with FILL, REACT, SETTLE, DRAW and IDLE periods in the ratio of 0.5: 3.5: 1.0: 0.75 :0.25 for a cycle time of 6 h. In the presence of 10 mg/L Cu(II) and 30 mg/L Cd(II), respectively, the average COD removal efficiencies were above 85% with the PAC dosage in the influent solution at 143 mg/L compared to around 60% without PAC addition. Copper(II) was found to exert a more pronounced inhibitory effect on the bioactivity of the microorganisms compared to Cd(II). It was observed that the combined presence of Cu(II) and Cd(II) did not exert synergistic effects on the microorganisms. Kinetic study conducted for the REACT period showed that the addition of PAC had minimized the inhibitory effect of the heavy metals on the bioactivity of microorganisms.

  10. Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill.

    PubMed

    Sánchez, Antoni

    2009-08-01

    This discussion explores one crucial point about the use of biodegradability indicators to monitor biological processes in organic solid waste treatment plants. Today, some different measures are being used for the determination of biodegradable organic matter and most of them are based on respiration indices (oxygen consumption or carbon dioxide production under aerobic conditions) or biogas production tests (under strict anaerobic conditions). However, it is not evident from scientific literature that both tests may be equivalent or comparable. This discussion includes the results obtained when trying to correlate both anaerobic and aerobic tests to complement the recent work published by Wagland et al. [Wagland, S.T., Tyrrel, S.F., Godley, A.R., Smith, R., 2009. Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill. Waste Management 29, 1218-1226].

  11. Multiphase Modeling of Flow, Transport, and Biodegradation in a Mesoscale Landfill Bioreactor

    SciTech Connect

    Oldenburg, Curtis M.; Borglin, Sharon E.; Hazen, Terry C.

    2002-02-01

    The need to control gas and leachate production and minimize refuse volume in municipal solid waste landfills has motivated the development of landfill simulation models to predict and design optimal treatment processes. We have developed a multiphase and multicomponent nonisothermal module called T2LBM for the three-dimensional TOUGH2 flow and transport simulator. T2LBM can be used to simulate aerobic or anaerobic biodegradation of municipal solid waste and the associated flow and transport of gas and liquid through the refuse mass. Acetic acid is used as a proxy for all biodegradable substrates in the refuse. T2LBM incorporates a Monod kinetic rate law for the biodegradation of acetic acid by either aerobic or anaerobic microbes as controlled by the local oxygen concentration. We have verified the model against published data, and applied it to our own mesoscale laboratory aerobic landfill bioreactor experiments. We observe spatial variability of flow and biodegradation consistent with permeability heterogeneity and the geometry of the radial grid. The model is capable of matching results of a shut-in test where the respiration of the system is measured over time.

  12. Start-up of the SHARON and ANAMMOX process in landfill bioreactors using aerobic and anaerobic ammonium oxidising biomass.

    PubMed

    Shalini, S Sri; Joseph, Kurian

    2013-12-01

    The main aim of this study is to analyse the feasibility to use aerobic ammonium oxidising bacteria (AOB) and anammox/AnAOB biomass enriched from mined municipal solid waste for in situ SHARON and ANAMMOX processes in laboratory scale landfill bioreactors (LFBR) for ammonia nitrogen removal. For this purpose, three LFBRs were operated as Control (without biomass seed), SHARON (with AOB biomass seed) and ANAMMOX (with anammox biomass seed) for 315 days. Results showed nitrogen loading rate of 1.0 kg N/d was effectively removed in SHARON and ANAMMOX LFBR. In SHARON LFBR, partial nitritation efficiency reached up to 98.5% with AOB population of MPN of 5.1 × 10(6)/mL obtained. ANAMMOX LFBR gave evolution of 95% of nitrogen gas as the end product confirmed the ANAMMOX process. Nitrogen transformations, biomass development and hydrazine and hydroxylamine formation authenticated the enriched AOB and anammox biomass activity in landfill bioreactors.

  13. Treatment of artificial soybean wastewater anaerobic effluent in a continuous aerobic-anaerobic coupled (CAAC) process with excess sludge reduction.

    PubMed

    Wang, Jun; Li, Xiaoxia; Fu, Weichao; Wu, Shihan; Li, Chun

    2012-12-01

    In this study, treatment of artificial soybean wastewater anaerobic effluent was studied in a continuous aerobic-anaerobic coupled (CAAC) process. The focus was on COD and nitrogen removal as well as excess sludge reduction. During the continuous operation without reflux, the COD removal efficiency was 96.5% at the optimal hydraulic retention time (HRT) 1.3 days. When HRT was shortened to 1.0 day, reflux from anaerobic zone to moving bed biofilm reactor (MBBR) was introduced. The removal efficiencies of COD and TN were 94.4% and 76.0% at the optimal reflux ratio 30%, respectively. The sludge yield coefficient of CAAC was 0.1738, the simultaneous removal of COD and nitrogen with in situ sludge reduction could be achieved in this CAAC process. The sludge reduction mechanism was discussed by soluble components variation along the water flow.

  14. Biodegradability enhancement and detoxification of cork processing wastewater molecular size fractions by ozone.

    PubMed

    Santos, Diana C; Silva, Lúcia; Albuquerque, António; Simões, Rogério; Gomes, Arlindo C

    2013-11-01

    Cork boiling wastewater pollutants were fractionated by sequential use of four ultrafiltration membranes and five fractions were obtained: four retentates (>100, 50-100, 20-50 and 10-20 kDa) and one permeate (<10 kDa); which were used to study the correlation of molecular size with biodegradability and toxicity before and after ozonation. The results show that molecular size is correlated with organic load and restrains biodegradability. The fraction with >100 kDa corresponds to 56% of the organic load and the one with <10 kDa only 8%. The biodegradability of fractions increased 182% with fractions molecular size reduction from >100 to <10 kDa and the chemical oxygen demand (COD) was from 3436 to 386 mg L(-1). For biodegradability enhancement the best outcome of ozonation was obtained with compounds having molecular size >20 kDa and range from 5% up to 175% for applied ozone doses to COD ratios between 0.15 and 0.38.

  15. In situ aerobic cometabolism of chlorinated solvents: a review.

    PubMed

    Frascari, Dario; Zanaroli, Giulio; Danko, Anthony S

    2015-01-01

    The possible approaches for in situ aerobic cometabolism of aquifers and vadose zones contaminated by chlorinated solvents are critically evaluated. Bioaugmentation of resting-cells previously grown in a fermenter and in-well addition of oxygen and growth substrate appear to be the most promising approaches for aquifer bioremediation. Other solutions involving the sparging of air lead to satisfactory pollutant removals, but must be integrated by the extraction and subsequent treatment of vapors to avoid the dispersion of volatile chlorinated solvents in the atmosphere. Cometabolic bioventing is the only possible approach for the aerobic cometabolic bioremediation of the vadose zone. The examined studies indicate that in situ aerobic cometabolism leads to the biodegradation of a wide range of chlorinated solvents within remediation times that vary between 1 and 17 months. Numerous studies include a simulation of the experimental field data. The modeling of the process attained a high reliability, and represents a crucial tool for the elaboration of field data obtained in pilot tests and for the design of the full-scale systems. Further research is needed to attain higher concentrations of chlorinated solvent degrading microbes and more reliable cost estimates. Lastly, a procedure for the design of full-scale in situ aerobic cometabolic bioremediation processes is proposed.

  16. Biodegradation of vapor-phase toluene in unsaturated porous media: Column experiments.

    PubMed

    Khan, Ali M; Wick, Lukas Y; Harms, Hauke; Thullner, Martin

    2016-04-01

    Biodegradation of organic chemicals in the vapor phase of soils and vertical flow filters has gained attention as promising approach to clean up volatile organic compounds (VOC). The drivers of VOC biodegradation in unsaturated systems however still remain poorly understood. Here, we analyzed the processes controlling aerobic VOC biodegradation in a laboratory setup mimicking the unsaturated zone above a shallow aquifer. The setup allowed for diffusive vapor-phase transport and biodegradation of three VOC: non-deuterated and deuterated toluene as two compounds of highly differing biodegradability but (nearly) identical physical and chemical properties, and MTBE as (at the applied experimental conditions) non-biodegradable tracer and internal control. Our results showed for toluene an effective microbial degradation within centimeter VOC transport distances despite high gas-phase diffusivity. Degradation rates were controlled by the reactivity of the compounds while oxic conditions were found everywhere in the system. This confirms hypotheses that vadose zone biodegradation rates can be extremely high and are able to prevent the outgassing of VOC to the atmosphere within a centimeter range if compound properties and site conditions allow for sufficiently high degradation rates.

  17. 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

  18. Reuse of recalcitrant-rich anaerobic effluent as dilution water after enhancement of biodegradability by Fenton processes.

    PubMed

    Arimi, Milton M; Zhang, Yongjun; Namango, Saul S; Geißen, Sven-Uwe

    2016-03-01

    Anaerobic digestion is used to treat effluents with a lot of organics, such as molasses distillery wastewater (MDW) which is the effluent of bioethanol production from molasses. The raw MDW requires a lot of dilution water before biodigestion, while the digested MDW has high level of recalcitrants which are problematic for its discharge. This study investigated ferric coagulation, Fenton, Fenton-like (with ferric ions as catalyst) processes and their combinations on the biodegradability of digested MDW. The Fenton and Fenton-like processes after coagulation increased the MDW biodegradability defined by (BOD5/COD) from 0.07 to (0.4-0.6) and saved 50% of H2O2 consumed in the classic Fenton process. The effluent from coagulation coupled to a Fenton-like process was used as dilution water for the raw MDW before the anaerobic digestion. The process was stable with volumetric loading of approx. 2.7 g COD/L/d. It resulted in increased overall biogas recovery and significantly decreased the demand for the dilution water.

  19. Production of biodegradable plastics from activated sludge generated from a food processing industrial wastewater treatment plant.

    PubMed

    Suresh Kumar, M; Mudliar, S N; Reddy, K M K; Chakrabarti, T

    2004-12-01

    Most of the excess sludge from a wastewater treatment plant (60%) is disposed by landfill. As a resource utilization of excess sludge, the production of biodegradable plastics using the sludge has been proposed. Storage polymers in bacterial cells can be extracted and used as biodegradable plastics. However, widespread applications have been limited by high production cost. In the present study, activated sludge bacteria in a conventional wastewater treatment system were induced, by controlling the carbon: nitrogen ratio to accumulate storage polymers. Polymer yield increased to a maximum 33% of biomass (w/w) when the C/N ratio was increased from 24 to 144, where as specific growth yield decreased with increasing C/N ratio. The conditions which are required for the maximum polymer accumulation were optimized and are discussed.

  20. Model based evaluation of a contaminant plume development under aerobic and anaerobic conditions in 2D bench-scale tank experiments.

    PubMed

    Ballarini, E; Beyer, C; Bauer, R D; Griebler, C; Bauer, S

    2014-06-01

    The influence of transverse mixing on competitive aerobic and anaerobic biodegradation of a hydrocarbon plume was investigated using a two-dimensional, bench-scale flow-through laboratory tank experiment. In the first part of the experiment aerobic degradation of increasing toluene concentrations was carried out by the aerobic strain Pseudomonas putida F1. Successively, ethylbenzene (injected as a mixture of unlabeled and fully deuterium-labeled isotopologues) substituted toluene; nitrate was added as additional electron acceptor and the anaerobic denitrifying strain Aromatoleum aromaticum EbN1 was inoculated to study competitive degradation under aerobic /anaerobic conditions. The spatial distribution of anaerobic degradation was resolved by measurements of compound-specific stable isotope fractionation induced by the anaerobic strain as well as compound concentrations. A fully transient numerical reactive transport model was employed and calibrated using measurements of electron donors, acceptors and isotope fractionation. The aerobic phases of the experiment were successfully reproduced using a double Monod kinetic growth model and assuming an initial homogeneous distribution of P. putida F1. Investigation of the competitive degradation phase shows that the observed isotopic pattern cannot be explained by transverse mixing driven biodegradation only, but also depends on the inoculation process of the anaerobic strain. Transient concentrations of electron acceptors and donors are well reproduced by the model, showing its ability to simulate transient competitive biodegradation.

  1. [Investigation of the process of personal hygiene items biodegradation by cellulose-fermenting microorganisms].

    PubMed

    Il'in, V K; Starkov, L V; Kostrov, S V; Belikodvorskaia, G A; Chuvil'skaia, N A; Mukhamedieva, L N; Mikos, K N

    2004-01-01

    Cellulose-containing wastes are one of the heaviest and biggest ingredients of solid domestic wastes piling up during spaceflight. For the most part these are disposable personal hygiene items used in large quantities in the absence of shower. These wastes contain human body products which are very dangerous from the sanitary-epidemiological standpoint. The purpose was to explore potentiality of microbial biodegradation of cellulose-containing hygiene items anaerobically with dry mass transformation into liquid and biogas. Among specific objectives were test cultivation of active strains of reference cultures of cellulose-fermenting anaerobic thermophilic bacteria on hygiene items as the only source of carbon, evaluation of ways and need of pretreatment of gauze pads to stimulate biodegradation, and chemical analysis of resulting biogas. From the investigation it was concluded that gauze pads are susceptible to biodegradation by anaerobic bacteria producing a low toxicity gas fraction. Therefore, the proposed technology can be considered as a candidate for integration into the spacecrew life support system.

  2. Partial degradation of levofloxacin for biodegradability improvement by electro-Fenton process using an activated carbon fiber felt cathode.

    PubMed

    Gong, Yuexiang; Li, Jiuyi; Zhang, Yanyu; Zhang, Meng; Tian, Xiujun; Wang, Aimin

    2016-03-05

    Solutions of 500 mL 200 mg L(-1) fluoroquinolone antibiotic levofloxacin (LEVO) have been degraded by anodic oxidation (AO), AO with electrogenerated H2O2 (AO-H2O2) and electro-Fenton (EF) processes using an activated carbon fiber (ACF) felt cathode from the point view of not only LEVO disappearance and mineralization, but also biodegradability enhancement. The LEVO decay by EF process followed a pseudo-first-order reaction with an apparent rate constant of 2.37×10(-2)min(-1), which is much higher than that of AO or AO-H2O2 processes. The LEVO mineralization also evidences the order EF>AO-H2O2>AO. The biodegradability (BOD5/COD) increased from 0 initially to 0.24, 0.09, and 0.03 for EF, AO-H2O2 and AO processes after 360 min treatment, respectively. Effects of several parameters such as current density, initial pH and Fe(2+) concentration on the EF degradation have also been examined. Three carboxylic acids including oxalic, formic and acetic acid were detected, as well as the released inorganic ions NH4(+), NO3(-) and F(-). At last, an ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry was used to identify about eight aromatic intermediates formed in 60 min of EF treatment, and a plausible mineralization pathway for LEVO by EF treatment was proposed.

  3. [Effect of different volume loading of aerobic/anaerobic zone on nitrogen and phosphorus removal by biofilm and granular sludge coupling process].

    PubMed

    Yin, Hang; Liu, Chang; Gao, Hui; Gao, Da-Wen

    2014-05-01

    The effect of different aerobic/anaerobic zone volume loading on nitrogen and phosphorus removal by biological film and granular coupling process was investigated using a self-designed Biofilm/Granular sludge coupling reactor. Three operating modes were conducted in the experiment. In operating mode I ,the volume of aerobic zone was 9. 66 L, and the volume of anaerobic zone was 15. 34 L. In operating mode II , the volume of aerobic zone was 12. 56 L, and the volume of anaerobic zone was 12. 44 L. In operating mode III , the volume of aerobic zone was 15.42 L, and the volume of anaerobic zone was 9.58 L. Three operating modes expressed different volume loading of the reactor because of different aerobic/anaerobic zone. The results showed that the performance of ammonia nitrogen and phosphorus removal was a bit poor in operating mode I , the effluent nitrate nitrogen was higher in operating mode III compared with other modes, which brought the total nitrogen removal efficiency lower. The operating mode II was optimal for nitrogen and phosphorus removal. In operating mode II , the ammonia nitrogen removal efficiency was about 80. 63% , the volume loading rate of nitrogen removal was about 150. 27 g(m3 d)-1, and the COD removal efficiency was higher than 83.24%; the amounts of phosphorus release and uptake under anaerobic conditions were 7. 23 mg L-1 and 11. 93 mg L-1.

  4. Electrospinning process: Versatile preparation method for biodegradable and natural polymers and biocomposite systems applied in tissue engineering and drug delivery

    NASA Astrophysics Data System (ADS)

    Rogina, Anamarija

    2014-03-01

    Over the past two decades, the electrospinning process has shown a great potential in various applications, such as membrane filtration, catalytic processes, fibrous-sensor applications, drug delivery and tissue engineering, due to ability of facile producing high surface-to-volume fibrous structure. The most appealing electrospinning characteristic has shown to be the mimicking nano-scale fibrous topography of extracellular matrix (ECM) in tissue engineering field. The wide range of electrospinnable synthetic biodegradable and natural polymers offers fabrication of fibrous nano-structures with specific biological responses and mechanical properties. Conducting different processing parameters (needle geometry, tip-to-collector distance, electric field strength, collector composition and geometry) allows the altering of fiber size, density, alignment and overall morphology. So far, electrospinning process has shown limitless application in tissue engineering and drug delivery. The following review has been focused on studies of electrospinning process as the most promising fabrication technique for tissue engineering and drug delivery applications.

  5. Evaluation of biodegradation-promoting additives for plastics.

    PubMed

    Selke, Susan; Auras, Rafael; Nguyen, Tuan Anh; Castro Aguirre, Edgar; Cheruvathur, Rijosh; Liu, Yan

    2015-03-17

    Biodegradation-promoting additives for polymers are increasingly being used around the world with the claim that they effectively render commercial polymers biodegradable. However, there is a lot of uncertainty about their effectiveness in degrading polymers in different environments. In this study, we evaluated the effect of biodegradation-promoting additives on the biodegradation of polyethylene (PE) and polyethylene terephthalate (PET). Biodegradation was evaluated in compost, anaerobic digestion, and soil burial environments. None of the five different additives tested significantly increased biodegradation in any of these environments. Thus, no evidence was found that these additives promote and/or enhance biodegradation of PE or PET polymers. So, anaerobic and aerobic biodegradation are not recommended as feasible disposal routes for nonbiodegradable plastics containing any of the five tested biodegradation-promoting additives.

  6. Biodegradation of free cyanide and subsequent utilisation of biodegradation by-products by Bacillus consortia: optimisation using response surface methodology.

    PubMed

    Mekuto, Lukhanyo; Ntwampe, Seteno Karabo Obed; Jackson, Vanessa Angela

    2015-07-01

    A mesophilic alkali-tolerant bacterial consortium belonging to the Bacillus genus was evaluated for its ability to biodegrade high free cyanide (CN(-)) concentration (up to 500 mg CN(-)/L), subsequent to the oxidation of the formed ammonium and nitrates in a continuous bioreactor system solely supplemented with whey waste. Furthermore, an optimisation study for successful cyanide biodegradation by this consortium was evaluated in batch bioreactors (BBs) using response surface methodology (RSM). The input variables, that is, pH, temperature and whey-waste concentration, were optimised using a numerical optimisation technique where the optimum conditions were found to be as follows: pH 9.88, temperature 33.60 °C and whey-waste concentration of 14.27 g/L, under which 206.53 mg CN(-)/L in 96 h can be biodegraded by the microbial species from an initial cyanide concentration of 500 mg CN(-)/L. Furthermore, using the optimised data, cyanide biodegradation in a continuous mode was evaluated in a dual-stage packed-bed bioreactor (PBB) connected in series to a pneumatic bioreactor system (PBS) used for simultaneous nitrification, including aerobic denitrification. The whey-supported Bacillus sp. culture was not inhibited by the free cyanide concentration of up to 500 mg CN(-)/L, with an overall degradation efficiency of ≥ 99 % with subsequent nitrification and aerobic denitrification of the formed ammonium and nitrates over a period of 80 days. This is the first study to report free cyanide biodegradation at concentrations of up to 500 mg CN(-)/L in a continuous system using whey waste as a microbial feedstock. The results showed that the process has the potential for the bioremediation of cyanide-containing wastewaters.

  7. Occurrence and Biodegradation of Nonylphenol in the Environment

    PubMed Central

    Mao, Zhen; Zheng, Xiao-Fei; Zhang, Yan-Qiu; Tao, Xiu-Xiang; Li, Yan; Wang, Wei

    2012-01-01

    Nonylphenol (NP) is an ultimate degradation product of nonylphenol polyethoxylates (NPE) that is primarily used in cleaning and industrial processes. Its widespread use has led to the wide existence of NP in various environmental matrices, such as water, sediment, air and soil. NP can be decreased by biodegradation through the action of microorganisms under aerobic or anaerobic conditions. Half-lives of biodegradation ranged from a few days to almost one hundred days. The degradation rate for NP was influenced by temperature, pH and additions of yeast extracts, surfactants, aluminum sulfate, acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, hydrogen peroxide, heavy metals, and phthalic acid esters. Although NP is present at low concentrations in the environment, as an endocrine disruptor the risks of long-term exposure to low concentrations remain largely unknown. This paper reviews the occurrence of NP in the environment and its aerobic and anaerobic biodegradation in natural environments and sewage treatment plants, which is essential for assessing the potential risk associated with low level exposure to NP and other endocrine disruptors. PMID:22312266

  8. INFLUENCE OF PROTOZOAN GRAZING ON CONTAMINANT BIODEGRADATION. (R825418)

    EPA Science Inventory

    The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator¯prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations....

  9. Ozone/UV treatment to enhance biodegradation of surfactants in industrial wastewater. CRADA final report

    SciTech Connect

    Cline, J.E.; Sullivan, P.F.; Lovejoy, M.A.; Collier, J.; Adams, C.D.

    1996-10-01

    The new owners of a surfactant manufacturing plant wanted to triple production but were limited by the plant`s wastewater treatment capacity. Mass balance calculations indicated that little aerobic biodegradation was occurring in the plant`s wastewater treatment system. Literature reviews and laboratory tests confirmed that as much as 60% of the plant`s products might resist aerobic biodegradation. Overall chemical losses, both solid and aqueous, were estimated at 3.8% of theoretical. Organic loadings to the wastewater treatment system were 170 kg/d of which 50 kg/d reached the biological treatment system. Pollution prevention measures have allowed a > 20% increase in production levels with a > 30% decrease in effluent volume and no increase in discharge of chemical oxygen demand (COD). A new dissolved air flotation (DAF) system removes 70% of the organic loading. Sludge volumes are lower by an order of magnitude than with the clarifier/drum-filter process it replaced.

  10. Carbon and Hydrogen Stable Isotope Fractionation Associated with the Aerobic and Anaerobic Degradation of Saturated and Alkylated Aromatic Hydrocarbons.

    PubMed

    Musat, Florin; Vogt, Carsten; Richnow, Hans H

    2016-01-01

    Saturated hydrocarbons (alkanes) and alkylated aromatic hydrocarbons are abundant environmental compounds. Hydrocarbons are primarily removed from the environment by biodegradation, a process usually associated with moderate carbon and significant hydrogen isotope fractionation allowing monitoring of biodegradation processes in the environment. Here, we review the carbon and hydrogen stable isotope fractionation associated with the cleavage of C-H bonds at alkyl chains of hydrocarbons. Propane, n-butane and ethylbenzene were used as model components for alkyl moieties of aliphatic and aromatic hydrocarbons with emphasis on the cleavage of the C-H bond without the involvement of molecular oxygen. The carbon and hydrogen isotope fractionation factors were further used to explore the diagnostic potential for characterizing the mode of bond cleavage under oxic and anoxic conditions. x039B; factors, calculated to correlate carbon and hydrogen fractionation, allowed to distinguish between aerobic and anaerobic biodegradation processes in the environment.

  11. KEY CONCEPTS IN BIODEGRADATION

    EPA Science Inventory

    This one hour segment of the course identifies the biological processes that degrade petroleum hydrocarbons and MTBE. It reviews the stoichiometry of hydrocarbon degradation by aerobic respiration, nitrate reduction, sulfate reduction, iron (III) reduction, and methanogenesis. ...

  12. Toxicity reduction and biodegradability enhancement of cork processing wastewaters by ozonation.

    PubMed

    Gomes, A C; Silva, L; Simões, R; Canto, N; Albuquerque, A

    2013-01-01

    Biodegradability enhancement and detoxification of cork boiling wastewater (CBW) are required for the successful implementation of biological treatment options. We studied the possibility of achieving these goals through ozonation pre-treatment by experimenting on the effect of ozone dose and pH. The CBW used had a pH of 5.81, a chemical oxygen demand (COD) of 1,865 mg L(-1), a biochemical oxygen demand (BOD5) of 498 mg L(-1) and total phenol (TP) and tannin compounds concentrations of 523 and 399 mg L(-1), respectively. The ozone doses ranged from 0.27 to 2.63 for the O3(applied)/COD0 ratios with samples at natural pH and set to 3.33 and 9.96. Ozonation allowed the BOD20/COD ratio (biodegradability index) to increase from 0.37 to 0.63 and a toxicity reduction from 3.08 to 1.24 TU (Microtox). The corresponding removals obtained were 15.2-62.0%, 38.4-83.2% and 56.7-92.1% for COD, TP and colour, respectively. The best outcome of ozonation pre-treatment requires O3(applied)/COD0 ratios over 1.5 and an acid pH. The increase of TP removals with ozone dose at acid pH led to biodegradability enhancement and CBW detoxification. However, for similar conditions the highest COD removals were obtained at alkaline pH due to the hydroxyl radicals' high oxidation ability but lack of selectivity.

  13. Simulation of reactive processes related to biodegradation in aquifers. 1. Structure of the three-dimensional reactive transport model

    NASA Astrophysics Data System (ADS)

    Schäfer, Dirk; Schäfer, Wolfgang; Kinzelbach, Wolfgang

    1998-05-01

    The reactive transport model TBC (transport, biochemistry, and chemistry) numerically solves the equations for reactive transport in three-dimensional saturated groundwater flow. A finite element approximation and a standard Galerkin method are used. Solute transport is coupled to microbially mediated organic carbon degradation. Microbial growth is assumed to follow Monod-type kinetics. Substrate consumption and release of metabolic products is coupled to microbial growth via yield coefficients and stoichiometric relations. Additionally, the effects of microbial activity on selected inorganic chemical species in the aquifer can be considered. TBC allows the user to specify a wide range of possible biochemical and chemical reactions in the input file. This makes TBC a powerful and flexible simulation tool. It was developed to simulate reactive processes related to in situ bioremediation, but further fields of application are laboratory column studies on redox processes coupled to organic carbon degradation, field cases of intrinsic biodegradation, and early diagenetic processes in sediments.

  14. Aerobic Tennis.

    ERIC Educational Resources Information Center

    Stewart, Michael J.; Ahlschwede, Robert

    1989-01-01

    Increasing the aerobic nature of tennis drills in the physical education class may be necessary if tennis is to remain a part of the public school curriculum. This article gives two examples of drills that can be modified by teachers to increase activity level. (IAH)

  15. Multistage treatment system for raw leachate from sanitary landfill combining biological nitrification-denitrification/solar photo-Fenton/biological processes, at a scale close to industrial--biodegradability enhancement and evolution profile of trace pollutants.

    PubMed

    Silva, Tânia F C V; Silva, M Elisabete F; Cunha-Queda, A Cristina; Fonseca, Amélia; Saraiva, Isabel; Sousa, M A; Gonçalves, C; Alpendurada, M F; Boaventura, Rui A R; Vilar, Vítor J P

    2013-10-15

    A multistage treatment system, at a scale close to the industrial, was designed for the treatment of a mature raw landfill leachate, including: a) an activated sludge biological oxidation (ASBO), under aerobic and anoxic conditions; b) a solar photo-Fenton process, enhancing the bio-treated leachate biodegradability, with and without sludge removal after acidification; and c) a final polishing step, with further ASBO. The raw leachate was characterized by a high concentration of humic substances (HS) (1211 mg CHS/L), representing 39% of the dissolved organic carbon (DOC) content, and a high nitrogen content, mainly in the form of ammonium nitrogen (>3.8 g NH4(+)-N/L). In the first biological oxidation step, a 95% removal of total nitrogen and a 39% mineralization in terms of DOC were achieved, remaining only the recalcitrant fraction, mainly attributed to HS (57% of DOC). Under aerobic conditions, the highest nitrification rate obtained was 8.2 mg NH4(+)-N/h/g of volatile suspended solids (VSS), and under anoxic conditions, the maximum denitrification rate obtained was 5.8 mg (NO2(-)-N + NO3(-)-N)/h/g VSS, with a C/N consumption ratio of 2.4 mg CH3OH/mg (NO2(-)-N + NO3(-)-N). The precipitation of humic acids (37% of HS) after acidification of the bio-treated leachate corresponds to a 96% DOC abatement. The amount of UV energy and H2O2 consumption during the photo-Fenton reaction was 30% higher in the experiment without sludge removal and, consequently, the reaction velocity was 30% lower. The phototreatment process led to the depletion of HS >80%, of low-molecular-weight carboxylate anions >70% and other organic micropollutants, thus resulting in a total biodegradability increase of >70%. The second biological oxidation allowed to obtain a final treated leachate in compliance with legal discharge limits regarding water bodies (with the exception of sulfate ions), considering the experiment without sludge. Finally, the high efficiency of the overall treatment

  16. Natural light-micro aerobic condition for PSB wastewater treatment: a flexible, simple, and effective resource recovery wastewater treatment process.

    PubMed

    Lu, Haifeng; Han, Ting; Zhang, Guangming; Ma, Shanshan; Zhang, Yuanhui; Li, Baoming; Cao, Wei

    2017-03-13

    Photosynthetic bacteria (PSB) have two sets of metabolic pathways. They can degrade pollutants through light metabolic under light-anaerobic or oxygen metabolic pathways under dark-aerobic conditions. Both metabolisms function under natural light-microaerobic condition, which demands less energy input. This work investigated the characteristics of PSB wastewater treatment process under that condition. Results showed that PSB had very strong adaptability to chemical oxygen demand (COD) concentration; with F/M of 5.2-248.5 mg-COD/mg-biomass, the biomass increased three times and COD removal reached above 91.5%. PSB had both advantages of oxygen metabolism in COD removal and light metabolism in resource recovery under natural light-microaerobic condition. For pollutants' degradation, COD, total organic carbon, nitrogen, and phosphorus removal reached 96.2%, 91.0%, 70.5%, and 92.7%, respectively. For resource recovery, 74.2% of C in wastewater was transformed into biomass. Especially, coexistence of light and oxygen promote N recovery ratio to 70.9%, higher than with the other two conditions. Further, 93.7% of N-removed was synthesized into biomass. Finally, CO2 emission reduced by 62.6% compared with the traditional process. PSB wastewater treatment under this condition is energy-saving, highly effective, and environment friendly, and can achieve pollution control and resource recovery.

  17. Full-scale demonstration of step feed concept for improving an anaerobic/anoxic/aerobic nutrient removal process.

    PubMed

    Ge, Shijian; Zhu, Yunpeng; Lu, Congcong; Wang, Shuying; Peng, Yongzhen

    2012-09-01

    A small wastewater treatment plant (WWTP) failed to meet effluent requirements of the first-A discharge standard in China, with the anaerobic/anoxic/oxic (A/A/O) process treating municipal and partial industrial wastewater. Thus an A/O step feed process (Anoxic/oxic/anoxic/oxic/anoxic/oxic) with floating plastic carriers in aerobic units was proposed to improve nutrient removal within the existing WWTP. Four main reform strategies were applied: (1) the original influent was divided into three streams which led into corresponding anoxic units; (2) floating plastic carriers were placed in the second and third oxic units; (3) nitrified liquid recycling was omitted; (4) channel shapes and sizes were adjusted between adjacent units to prevent backflow. After these modifications were implemented, the total nitrogen and phosphorus concentrations in the effluent were reduced from 20.8 to 14.2mg/L, and from 1.89 to 0.57 mg/L, respectively. Moreover, annual electricity consumption in the WWTP was reduced by 245 MWh as a result of these modifications.

  18. A novel bio-safe phase separation process for preparing open-pore biodegradable polycaprolactone microparticles.

    PubMed

    Salerno, Aurelio; Domingo, Concepción

    2014-09-01

    Open-pore biodegradable microparticles are object of considerable interest for biomedical applications, particularly as cell and drug delivery carriers in tissue engineering and health care treatments. Furthermore, the engineering of microparticles with well definite size distribution and pore architecture by bio-safe fabrication routes is crucial to avoid the use of toxic compounds potentially harmful to cells and biological tissues. To achieve this important issue, in the present study a straightforward and bio-safe approach for fabricating porous biodegradable microparticles with controlled morphological and structural features down to the nanometer scale is developed. In particular, ethyl lactate is used as a non-toxic solvent for polycaprolactone particles fabrication via a thermal induced phase separation technique. The used approach allows achieving open-pore particles with mean particle size in the 150-250 μm range and a 3.5-7.9 m(2)/g specific surface area. Finally, the combination of thermal induced phase separation and porogen leaching techniques is employed for the first time to obtain multi-scaled porous microparticles with large external and internal pore sizes and potential improved characteristics for cell culture and tissue engineering. Samples were characterized to assess their thermal properties, morphology and crystalline structure features and textural properties.

  19. Comparative Examination of the Olive Mill Wastewater Biodegradation Process by Various Wood-Rot Macrofungi

    PubMed Central

    Koutrotsios, Georgios; Zervakis, Georgios I.

    2014-01-01

    Olive mill wastewater (OMW) constitutes a major cause of environmental pollution in olive-oil producing regions. Sixty wood-rot macrofungi assigned in 43 species were evaluated for their efficacy to colonize solidified OMW media at initially established optimal growth temperatures. Subsequently eight strains of the following species were qualified: Abortiporus biennis, Ganoderma carnosum, Hapalopilus croceus, Hericium erinaceus, Irpex lacteus, Phanerochaete chrysosporium, Pleurotus djamor, and P. pulmonarius. Fungal growth in OMW (25%v/v in water) resulted in marked reduction of total phenolic content, which was significantly correlated with the effluent's decolorization. A. biennis was the best performing strain (it decreased phenolics by 92% and color by 64%) followed by P. djamor and I. lacteus. Increase of plant seeds germination was less pronounced evidencing that phenolics are only partly responsible for OMW's phytotoxicity. Laccase production was highly correlated with all three biodegradation parameters for H. croceus, Ph. chrysosporium, and Pleurotus spp., and so were manganese-independent and manganese dependent peroxidases for A. biennis and I. lacteus. Monitoring of enzymes with respect to biomass production indicated that Pleurotus spp., H. croceus, and Ph. chrysosporium shared common patterns for all three activities. Moreover, generation of enzymes at the early biodegradation stages enhanced the efficiency of OMW treatment. PMID:24987685

  20. Comparative examination of the olive mill wastewater biodegradation process by various wood-rot macrofungi.

    PubMed

    Koutrotsios, Georgios; Zervakis, Georgios I

    2014-01-01

    Olive mill wastewater (OMW) constitutes a major cause of environmental pollution in olive-oil producing regions. Sixty wood-rot macrofungi assigned in 43 species were evaluated for their efficacy to colonize solidified OMW media at initially established optimal growth temperatures. Subsequently eight strains of the following species were qualified: Abortiporus biennis, Ganoderma carnosum, Hapalopilus croceus, Hericium erinaceus, Irpex lacteus, Phanerochaete chrysosporium, Pleurotus djamor, and P. pulmonarius. Fungal growth in OMW (25%v/v in water) resulted in marked reduction of total phenolic content, which was significantly correlated with the effluent's decolorization. A. biennis was the best performing strain (it decreased phenolics by 92% and color by 64%) followed by P. djamor and I. lacteus. Increase of plant seeds germination was less pronounced evidencing that phenolics are only partly responsible for OMW's phytotoxicity. Laccase production was highly correlated with all three biodegradation parameters for H. croceus, Ph. chrysosporium, and Pleurotus spp., and so were manganese-independent and manganese dependent peroxidases for A. biennis and I. lacteus. Monitoring of enzymes with respect to biomass production indicated that Pleurotus spp., H. croceus, and Ph. chrysosporium shared common patterns for all three activities. Moreover, generation of enzymes at the early biodegradation stages enhanced the efficiency of OMW treatment.

  1. In situ biodegradation of a hydrocarbon-contaminated landfill

    SciTech Connect

    Arazzini, S.; Bocchieri, P.; Migliorini, G.; Rivara, L.; Tripaldi, G.

    1995-12-31

    The anaerobic and/or low-aeration biodegradation of urban waste, contaminated by polycyclic aromatic hydrocarbon (PAH) compounds and a spill of tar products, is described. Before the industrial plant was designed, laboratory tests were carried out to determine the process feasibility and define the biodegradation rate of the pollutants. Preliminary tests on bacteria growth efficiency in aerobic and anaerobic conditions were carried out in Erlenmeyer flasks and showed interesting results in both cases. Following these tests, four different laboratory reactors were assembled to simulate waste treatment under different operating conditions. During 3 months of continuous treatment, the tar and PAH contents were measured in the waste and in the leachate and the bacteria population growth was registered. Treatment results show pollutant degradation of nearly 90%.

  2. Zero-valent iron pretreatment for enhancing the biodegradability of Azo dyes.

    PubMed

    Perey, Jennie R; Chiu, Pei C; Huang, Chin-Pao; Cha, Daniel K

    2002-01-01

    Azo dyes are a group of chemicals that are largely resistant to aerobic biodegradation and persist in wastewater treatment processes. This study proposed that zero-valent iron can be used to reduce the azo bond, cleaving the dye molecule into products that are more amenable to mineralization by bacteria in biological treatment processes such as activated sludge. Batch anaerobic reduction experiments were performed using two azo dyes, orange G and orange II, to determine reaction kinetics and to identify reduction products. Iron-treated dye solutions were subjected to batch biodegradation tests and respirometric analyses to screen for enhanced biodegradability over parent dyes. Results indicate that treatment of orange G and orange II with scrap iron produces aniline and sulfanilic acid as significant products that are degraded by an acclimated culture within 24 hours. Respirometric data illustrated that iron-treated dye solutions exert a significantly higher biochemical oxygen demand than the solutions containing orange G and orange II, demonstrating that recalcitrant azo dyes can be aerobically biodegraded after iron pretreatment.

  3. Synthesis and 3D printing of biodegradable polyurethane elastomer by a water-based process for cartilage tissue engineering applications.

    PubMed

    Hung, Kun-Che; Tseng, Ching-Shiow; Hsu, Shan-Hui

    2014-10-01

    Biodegradable materials that can undergo degradation in vivo are commonly employed to manufacture tissue engineering scaffolds, by techniques including the customized 3D printing. Traditional 3D printing methods involve the use of heat, toxic organic solvents, or toxic photoinitiators for fabrication of synthetic scaffolds. So far, there is no investigation on water-based 3D printing for synthetic materials. In this study, the water dispersion of elastic and biodegradable polyurethane (PU) nanoparticles is synthesized, which is further employed to fabricate scaffolds by 3D printing using polyethylene oxide (PEO) as a viscosity enhancer. The surface morphology, degradation rate, and mechanical properties of the water-based 3D-printed PU scaffolds are evaluated and compared with those of polylactic-co-glycolic acid (PLGA) scaffolds made from the solution in organic solvent. These scaffolds are seeded with chondrocytes for evaluation of their potential as cartilage scaffolds. Chondrocytes in 3D-printed PU scaffolds have excellent seeding efficiency, proliferation, and matrix production. Since PU is a category of versatile materials, the aqueous 3D printing process developed in this study is a platform technology that can be used to fabricate devices for biomedical applications.

  4. Presence of Aerobic Microorganisms, Enterobacteriaceae and Salmonella in the Shell Egg Processing Environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sanitation is vital to providing safe, healthy food to consumers. Understanding the degree to which microorganisms persist on specific equipment or locations contributes to developing effective sanitation programs. Certain microbial populations may be used to determine areas within a processing pl...

  5. [Microbiological processes at the interface of aerobic and anaerobic waters in the deep-water zone of the Black Sea].

    PubMed

    Pimenov, N V; Rusanov, I I; Iusupov, S K; Fridrich, J; Lein, A Iu; Wehrli, B; Ivanov, M V

    2000-01-01

    Chemical and key microbiological processes (assimilation of carbon dioxide, oxidation and formation of methane, and sulfate reduction) occurring at the boundary between the aerobic-anaerobic interface in the deep-water zone of the Black Sea were investigated. Measurements were taken at depths from 90 to 300 m at intervals of 5-10 m. The integral rate of the dark assimilation of carbon dioxide varied from 120 to 207 mg C/(m2 day) with a maximum at the boundary of cyclonic currents. The organic matter (OM) formed from methane comprised less than 5% of the OM formed from carbon dioxide. A comparison between the rates of methane oxidation and methane production suggests that methane that is oxidized at depths from 100 to 300 m was formed in deeper water horizons. The maximum rate of sulfate reduction (1230 mg S/(m2 day)) was observed in the western halistatic region, and the minimum rate (490 mg S/(m2 day)), in the eastern halistatic region. The average rate of hydrogen sulfide production measured at three deep-sea stations amounted to 755 mg S/(m2 day), or 276 g S/(m2 year).

  6. Phosphorus removal and greenhouse gas N2O emission in a lime-induced aerobic sludge granule process.

    PubMed

    Wu, X L; Guan, Y T; Zhang, X; Huang, X; Qian, Y

    2002-06-01

    Aerobic sludge granulation was achieved in an activated sludge process continuously fed with lime (Ca2+ 100 mg l(-1) influent) every other day. Eighteen days after lime addition, activated sludge granules with the size of 0.5-2.2 mm were formed, which occupied 10-25% of total sludge volume. Sludge volume index (SVI) was reduced to an average of 50 ml g(-1), which increased average sludge concentration to 3.6-5.0 g VSS l(-1), 1.6-2.1 times of that of control. Greenhouse gas N2O emission was also significantly reduced: N2O concentration from the lime-addition reactor was 5-15 ppmv, 47-61% of that of control, Effluent PO4-P concentration was generally lower than 1 mg l(-1) when average influent PO4-P concentration was 6.07-6.37 mg l(-1). Total phosphorus (TP) and total nitrogen (TN) removal efficiencies were around 89.6% and 14.5-16.1%, over 3.5 and 1 times higher than those of control, respectively. COD removal rate in the lime-addition reactor was 2.05-2.48 kg COD m(-3) d(-1), higher than 1.34-1.61 kg COD m(-3) d(-1) in the control.

  7. 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

  8. DEVELOPMENT OF BIOPLUME 4 MODEL FOR FUELS AND CHLORINATED SOLVENT BIODEGRADATION

    EPA Science Inventory

    The Bioplume model has been in development and use for modeling biodegradation and natural attenuation since the late 1980s. Bioplume 1 focused on aerobic biodegradation of BTEX. Bioplume II simulated oxygen and hydrocarbons and simulated biodegradation using an instantaneous r...

  9. DEVELOPMENT OF BIOPLUME4 MODEL FOR FUELS AND CHLORINATED SOLVENT BIODEGRADATION

    EPA Science Inventory

    The Bioplume model has been in development and use for modeling biodegradation and natural attenuation since the late 80's. Bioplume I focused on aerobic biodegradation of BTEX. Bioplume II simulated oxygen and hydrocarbons and simulated biodegradation using an instantaneous re...

  10. The primary biodegradation of dispersed crude oil in the sea.

    PubMed

    Prince, Roger C; McFarlin, Kelly M; Butler, Josh D; Febbo, Eric J; Wang, Frank C Y; Nedwed, Tim J

    2013-01-01

    Dispersants are important tools for stimulating the biodegradation of large oil spills. They are essentially a bioremediation tool - aiming to stimulate the natural process of aerobic oil biodegradation by dispersing oil into micron-sized droplets that become so dilute in the water column that the natural levels of biologically available nitrogen, phosphorus and oxygen are sufficient for microbial growth. Many studies demonstrate the efficacy of dispersants in getting oil off the water surface. Here we show that biodegradation of dispersed oil is prompt and extensive when oil is present at the ppm levels expected from a successful application of dispersants - more than 80% of the hydrocarbons of lightly weathered Alaska North Slope crude oil were degraded in 60 d at 8 °C in unamended New Jersey (USA) seawater when the oil was present at 2.5 ppm by volume. The apparent halftime of the biodegradation of the hydrocarbons was 13.8 d in the absence of dispersant, and 11 d in the presence of Corexit 9500 - similar to rates extrapolated from the field in the Deepwater Horizon response.

  11. Thinking big: towards ideal strains and processes for large-scale aerobic biofuels production

    SciTech Connect

    McMillan, James D.; Beckham, Gregg T.

    2016-12-22

    Global concerns about anthropogenic climate change, energy security and independence, and environmental consequences of continued fossil fuel exploitation are driving significant public and private sector interest and financing to hasten development and deployment of processes to produce renewable fuels, as well as bio-based chemicals and materials, towards scales commensurate with current fossil fuel-based production. Over the past two decades, anaerobic microbial production of ethanol from first-generation hexose sugars derived primarily from sugarcane and starch has reached significant market share worldwide, with fermentation bioreactor sizes often exceeding the million litre scale. More recently, industrial-scale lignocellulosic ethanol plants are emerging that produce ethanol from pentose and hexose sugars using genetically engineered microbes and bioreactor scales similar to first-generation biorefineries.

  12. Black and White race differences in aerobic capacity, muscle fiber type, and their influence on metabolic processes.

    PubMed

    Ceaser, Tyrone; Hunter, Gary

    2015-05-01

    Obesity is a known risk factor for cardiometabolic disease. Increasing aerobic capacity (VO2max) reduces adiposity, maintains weight, and reduces the risk of developing obesity and cardiometabolic disease. Two major determinants of aerobic capacity are the metabolic properties specific to a particular muscle fiber type and the capacity of the cardiorespiratory system to deliver nutrient-rich content to the muscle. Recent research suggests that some race/ethnic groups, particularly non-Hispanic Black subjects, are predisposed to a reduced VO2max by way of muscle fiber type. Combined with insufficient physical activity, these characteristics place non-Hispanic Black subjects at an increased risk for obesity and other adverse health outcomes when compared with other race/ethnic groups. The purpose of this review was to suggest a model for explaining how skeletal muscle fiber type may contribute to reduced aerobic capacity and obesity among non-Hispanic Black subjects. Our review indicates that metabolic properties of type II skeletal muscle (e.g. reduced oxidative capacity, capillary density) are related to various cardiometabolic diseases. Based on the review, non-Hispanic Black subjects appear to have a lower maximal aerobic capacity and a greater percentage of type II skeletal muscle fibers. Combined with reduced energy expenditure and reduced hemoglobin concentration, non-Hispanic Black subjects may be inherently predisposed to a reduced maximal aerobic capacity compared with non-Hispanic White subjects, thereby increasing the risk for obesity and related metabolic diseases.

  13. Effect of process design and operating parameters on aerobic methane oxidation in municipal WWTPs.

    PubMed

    Daelman, Matthijs R J; Van Eynde, Tamara; van Loosdrecht, Mark C M; Volcke, Eveline I P

    2014-12-01

    Methane is a potent greenhouse gas and its emission from municipal wastewater treatment plants (WWTPs) should be prevented. One way to do this is to promote the biological conversion of dissolved methane over stripping in aeration tanks. In this study, the well-established Activated Sludge Model n°1 (ASM1) and Benchmark Simulation Model n°1 (BSM1) were extended to study the influence of process design and operating parameters on biological methane oxidation. The aeration function used in BSM 1 was upgraded to more accurately describe gas-liquid transfer of oxygen and methane in aeration tanks equipped with subsurface aeration. Dissolved methane could be effectively removed in an aeration tank at an aeration rate that is in agreement with optimal effluent quality. Subsurface bubble aeration proved to be better than surface aeration, while a CSTR configuration was superior to plug flow conditions in avoiding methane emissions. The conversion of methane in the activated sludge tank benefits from higher methane concentrations in the WWTP's influent. Finally, if an activated sludge tank is aerated with methane containing off-gas, a limited amount of methane is absorbed and converted in the mixed liquor. This knowledge helps to stimulate the methane oxidizing capacity of activated sludge in order to abate methane emissions from wastewater treatment to the atmosphere.

  14. Decolorization of anthraquinone dye intermediate and its accelerating effect on reduction of azo acid dyes by Sphingomonas xenophaga in anaerobic-aerobic process.

    PubMed

    Lu, Hong; Zhou, Jiti; Wang, Jing; Ai, Haixin; Zheng, Chunli; Yang, Yusuo

    2008-09-01

    Decolorization of 1-aminoanthraquinone-2-sulfonic acid (ASA-2) and its accelerating effect on the reduction of azo acid dyes by Sphingomonas xenophaga QYY were investigated. The study showed that ASA-2 could be efficiently decolorized by strain QYY under aerobic conditions according to the analysis of total organic carbon removal and UV-VIS spectra changes. Moreover, strain QYY was able to reduce azo acid dyes under anaerobic conditions. The effects of various operating conditions such as carbon sources, temperature, and pH on the reduction rate were studied. It was demonstrated that ASA-2 used as a redox mediator could accelerate the reduction process. Consequently the reduction of azo acid dyes mediated by ASA-2 and the decolorization of ASA-2 with strain QYY could be achieved in an anaerobic-aerobic process.

  15. Anaerobic/aerobic treatment of a petrochemical wastewater from two aromatic transformation processes by fluidized bed reactors.

    PubMed

    Estrada-Arriaga, Edson B; Ramirez-Camperos, Esperanza; Moeller-Chavez, Gabriela E; García-Sanchez, Liliana

    2012-01-01

    An integrated fluidized bed reactor (FBR) has been employed as the treatment for petrochemical industry wastewaters with high organic matter and aromatic compounds, under anaerobic and aerobic conditions. The system was operated at hydraulic residence time (HRT) of 2.7 and 2.2 h in the anaerobic and aerobic reactor, respectively. The degree of fluidization in the beds was 30%. This system showed a high performance on the removal of organic matter and aromatic compounds. At different organic loading rates (OLR), the chemical oxygen demand (COD) removal in the anaerobic reactor was close to 85% and removals of the COD up to 94% were obtained in the aerobic reactor. High removals of benzene, toluene, ethylbenzene, xylenes, styrene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene and naphthalene were achieved in this study.

  16. Recalcitrant organic matter removal from textile wastewater by an aerobic cell-immobilized pellet column.

    PubMed

    Kim, Moonil; Han, Dukkyu; Cui, Fenghao; Bae, Wookeun

    2013-01-01

    The treatment of textile wastewater is difficult because of its recalcitrant organic content. The biological removal of recalcitrant organics requires a long retention time for microbial growth. Activated sludge was immobilized in a polyethylene glycol pellet to allow for sufficient sludge retention time. The pellets were filled in an aerobic cell-immobilized pellet column (CIPC) reactor in order to investigate the removal of recalcitrant organics from textile wastewater. A textile wastewater effluent treated by a conventional activated sludge reactor was used as a target wastewater. The chemical oxygen demand (COD) removal efficiency of the aerobic CIPC reactor at various empty bed contact times was in the range of 42.2-60.5%. Half of the input COD was removed in the lower part (bottom 25% of the reactor volume) of the reactor when the organic loading rate was less than 1.5 kg COD/(m(3)•d). About 15-30% of the input COD was removed in the remaining part of the column reactor. The COD removed in this region was limitedly biodegradable. The biodegradation of recalcitrant organics could be carried out by the interactional functions of the various bacteria consortia by using a cell-immobilization process. The CIPC process could effectively treat textile wastewater using a short retention time because the microorganisms that degrade limitedly biodegradable organics were dominant in the reactor.

  17. The functional TiO2-biodegradable plastic composite material produced by HVOF spraying process.

    PubMed

    Bang, Hee-Seon; Bang, Han-Sur; Lee, Yoon-Ki

    2007-11-01

    Photocatalytic TiO2 coatings on bio-degradable plastic(polybutylene succinate: PBS) were prepared by HVOF spraying using three kinds of agglomerated powders (P200: 200 nm, P30: 30 nm, P7: 7 nm). The microstructures of the coatings were characterized with SEM and XRD analysis, and the photocatalytic efficiency of the coatings was evaluated by photo degradation of gaseous acetaldehyde. For both the HVOF sprayed P200 and P30 coatings, high anatase ratio of 100% was achieved, regardless of the fuel gas pressure. On the other hand, for the HVOF sprayed P7 coating, the anatase ratio decreased from 100% to 49.1% with increasing fuel gas pressure. This decrease may be attributed to the much higher susceptibility to heat of the 7 nm agglomerated powders than the 30 nm and 200 nm agglomerated powders. In terms of the photocatalytic efficiency, HVOF sprayed P200 and P30 coatings seemed to outperform the P7 coatings because of their higher anatase ratios. However, the HVOF sprayed P7 coatings did not show photocatalytic activity possibly because of the extremely small reaction surface area to the photo-catalytic activity and low anatase ratio. Therefore, the present study found that functional PBS plastic with photocatalytic performance could be produced by spraying of ceramics such as TiO2.

  18. Transformation of metamitron in water-sediment systems: Detailed insight into the biodegradation processes.

    PubMed

    Wang, Shizong; Miltner, Anja; Kästner, Matthias; Schäffer, Andreas; Nowak, Karolina M

    2017-02-01

    Metamitron and its main metabolite desamino-metamitron are frequently detected in surface waters. To date, there are no studies targeting metamitron degradation in water-sediment systems. Therefore, the aim of this study was to trace the fate of metamitron in a water-sediment system using (13)C-isotope labeling. Mineralization of metamitron was high and accounted for 49% of (13)C6-metamitron equivalents at the end. In contrast, only 8.7% of (13)C6-metamitron equivalents were mineralized in the water only system demonstrating the key role of sediment for biodegradation. Metamitron disappeared from the water on day 40 and was completely removed from the sediment on day 80. This agrochemical was utilized as carbon source by microorganisms as shown by the incorporation of the (13)C label into microbial amino acids and finally into biogenic residues. The latter amounted to 24% of (13)C6-metamitron equivalents at the end. However, 17% of (13)C6-metamitron equivalents were detected in xenobiotic non-extractable residues (NER) with a release potential and delayed risk for the environment. Metamitron was degraded via two pathways, initially via 4-(dimethylimino)-3-methyl-6-phenyl-1,2,4-triazin-5(4H)-one, which might be related to growth, and later via desamino-metamitron, which can be attributed to starvation.

  19. Self Potential as an indicator of biogeochemical transformations during active hydrocarbon biodegradation processes

    NASA Astrophysics Data System (ADS)

    Ntarlagiannis, D.; Heenan, J. W.; Slater, L. D.; Atekwana, E. A.; Rossbach, S.; Beaver, C. L.; Revil, A.; Bekins, B. A.

    2015-12-01

    Self potential (SP) signals, collected from borehole installation at the National Crude Oil Spill Fate and Natural Attenuation Research Site at Bemidji (MN), show a strong bipolar anomaly centered around the smear zone where intense bioremediation is known to occur. Magnetic susceptibility (MS) and geochemical analysis of soil cores confirmed the presence of a magnetite layer at the smear zone. The observed anomaly is consistent with the operation of a bio-geobattery centered on the conductive magnetite. This bio-geobattery is not permanent, but instead periodically shuts down, while at other times it reaches a maximum potential difference of ~ 70mV. The transient operation of the bio-geobattery appears to be associated with changes in the gradient of the redox species in the vicinity of the magnetite layer. Microbiological analysis of the soil cores identified microbial species that can support the operation of a bio-geobattery with the anode located below the magnetite, and the cathode above the magnetite layer. Environmental conditions local to the smear zone (e.g. water table change, rain water infiltration) seem to change the microbial dynamics around the magnetite layer resulting in redox gradient changes, essentially turning 'on' and 'off' the bio-geobattery. This work provides strong field-scale evidence for the functioning of a biogeobattery resulting from long-term biodegradation of a crude oil spill.

  20. Quantitative proteomics and transcriptomics of anaerobic and aerobic yeast cultures reveals post-transcriptional regulation of key cellular processes.

    PubMed

    de Groot, Marco J L; Daran-Lapujade, Pascale; van Breukelen, Bas; Knijnenburg, Theo A; de Hulster, Erik A F; Reinders, Marcel J T; Pronk, Jack T; Heck, Albert J R; Slijper, Monique

    2007-11-01

    Saccharomyces cerevisiae is unique among yeasts in its ability to grow rapidly in the complete absence of oxygen. S. cerevisiae is therefore an ideal eukaryotic model to study physiological adaptation to anaerobiosis. Recent transcriptome analyses have identified hundreds of genes that are transcriptionally regulated by oxygen availability but the relevance of this cellular response has not been systematically investigated at the key control level of the proteome. Therefore, the proteomic response of S. cerevisiae to anaerobiosis was investigated using metabolic stable-isotope labelling in aerobic and anaerobic glucose-limited chemostat cultures, followed by relative quantification of protein expression. Using independent replicate cultures and stringent statistical filtering, a robust dataset of 474 quantified proteins was generated, of which 249 showed differential expression levels. While some of these changes were consistent with previous transcriptome studies, many of the responses of S. cerevisiae to oxygen availability were, to our knowledge, previously unreported. Comparison of transcriptomes and proteomes from identical cultivations yielded strong evidence for post-transcriptional regulation of key cellular processes, including glycolysis, amino-acyl-tRNA synthesis, purine nucleotide synthesis and amino acid biosynthesis. The use of chemostat cultures provided well-controlled and reproducible culture conditions, which are essential for generating robust datasets at different cellular information levels. Integration of transcriptome and proteome data led to new insights into the physiology of anaerobically growing yeast that would not have been apparent from differential analyses at either the mRNA or protein level alone, thus illustrating the power of multi-level studies in yeast systems biology.

  1. Biodegradable Polymers for the Environment

    NASA Astrophysics Data System (ADS)

    Gross, Richard A.; Kalra, Bhanu

    2002-08-01

    Biodegradable polymers are designed to degrade upon disposal by the action of living organisms. Extraordinary progress has been made in the development of practical processes and products from polymers such as starch, cellulose, and lactic acid. The need to create alternative biodegradable water-soluble polymers for down-the-drain products such as detergents and cosmetics has taken on increasing importance. Consumers have, however, thus far attached little or no added value to the property of biodegradability, forcing industry to compete head-to-head on a cost-performance basis with existing familiar products. In addition, no suitable infrastructure for the disposal of biodegradable materials exists as yet.

  2. Ecotoxicity effects triggered in aquatic organisms by invasive Acer negundo and native Alnus glutinosa leaf leachates obtained in the process of aerobic decomposition.

    PubMed

    Manusadžianas, Levonas; Darginavičienė, Jūratė; Gylytė, Brigita; Jurkonienė, Sigita; Krevš, Alina; Kučinskienė, Alė; Mačkinaitė, Rimutė; Pakalnis, Romas; Sadauskas, Kazys; Sendžikaitė, Jūratė; Vitkus, Rimantas

    2014-10-15

    The replacement of autochthonous tree species by invasive ones in coastal zones of freshwater bodies induces additional alteration of hydrochemical and microbiological characteristics due to decomposition of fallen leaves of non-indigenous species, which can lead to ecotoxic response of the littoral biota. Leaves of invasive to Lithuania boxelder maple (Acer negundo) and autochthonous black alder (Alnus glutinosa) lost more than half of biomass and released stable amount of DOC (60-70 mg/L) throughout 90-day mesocosm experiment under aerobic conditions. This, along with the relatively small BOD7 values detected after some variation within the first month confirms effective biodegradation by fungi and bacteria. The ambient water was more enriched with different forms of N and P by decomposing boxelder maple than by alder leaves. During the first month, both leachates were more toxic to charophyte (Nitellopsis obtusa) at mortality and membrane depolarization levels, while later to two crustacean species. Biomarker response, H(+)-ATPase activity in membrane preparations from N. obtusa, was stronger for A. negundo. Generally, boxelder maple leaf leachates were more toxic to tested hydrobionts and this coincides with previous study on leaves of the same pair of tree species conducted under microaerobic conditions (Krevš et al., 2013).

  3. Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

  4. Effects of carbon dioxide on the fate of Listeria monocytogenes, of aerobic bacteria and on the development of spoilage in minimally processed fresh endive.

    PubMed

    Carlin, F; Nguyen-the, C; Abreu Da Silva, A; Cochet, C

    1996-09-01

    Minimally processed fresh broad-leaved endive (Cichorium endivia L.) were stored at 3 and 10 degrees C in modified atmospheres containing air, 10% CO2/10% O2, 30% CO2/10% O2, and 50% CO2/10% O2. The effects of these modified atmospheres on the fate of both aerobic bacteria and three strains of Listeria monocytogenes, was investigated. Increases in CO2 concentrations significantly reduced the growth of the aerobic microflora. The best preservation of the visual quality occurred on endive leaves stored in 10% CO2/10% O2, whereas leaves stored in 30% CO2/10% O2 and 50% CO2/10% O2, and to a lesser extent in air, showed extensive spoilage after storage. Listeria monocytogenes was slightly affected at 3 degrees C by the modified atmospheres, as compared to air. At 10 degrees C, results varied between replicate experiments, but L. monocytogenes generally grew better as the CO2 concentration was increased. The three test strains behaved in a similar way. In conclusion, among the modified atmospheres tested, a modified atmosphere containing 10% CO2/10% O2 resulted in improved visual quality of minimally processed fresh endive, without a marked effect on the growth of the aerobic microflora or of L. monocytogenes.

  5. Effect of aerobic pre-treatment on hydrogen and methane production in a two-stage anaerobic digestion process using food waste with different compositions.

    PubMed

    Rafieenia, Razieh; Girotto, Francesca; Peng, Wei; Cossu, Raffaello; Pivato, Alberto; Raga, Roberto; Lavagnolo, Maria Cristina

    2017-01-01

    Aerobic pre-treatment was applied prior to two-stage anaerobic digestion process. Three different food wastes samples, namely carbohydrate rich, protein rich and lipid rich, were prepared as substrates. Effect of aerobic pre-treatment on hydrogen and methane production was studied. Pre-aeration of substrates showed no positive impact on hydrogen production in the first stage. All three categories of pre-aerated food wastes produced less hydrogen compared to samples without pre-aeration. In the second stage, methane production increased for aerated protein rich and carbohydrate rich samples. In addition, the lag phase for carbohydrate rich substrate was shorter for aerated samples. Aerated protein rich substrate yielded the best results among substrates for methane production, with a cumulative production of approximately 351ml/gVS. With regard to non-aerated substrates, lipid rich was the best substrate for CH4 production (263ml/gVS). Pre-aerated P substrate was the best in terms of total energy generation which amounted to 9.64kJ/gVS. This study revealed aerobic pre-treatment to be a promising option for use in achieving enhanced substrate conversion efficiencies and CH4 production in a two-stage AD process, particularly when the substrate contains high amounts of proteins.

  6. Microbiology and potential applications of aerobic methane oxidation coupled to denitrification (AME-D) process: A review.

    PubMed

    Zhu, Jing; Wang, Qian; Yuan, Mengdong; Tan, Giin-Yu Amy; Sun, Faqian; Wang, Cheng; Wu, Weixiang; Lee, Po-Heng

    2016-03-01

    Aerobic methane oxidation coupled to denitrification (AME-D) is an important link between the global methane and nitrogen cycles. This mini-review updates discoveries regarding aerobic methanotrophs and denitrifiers, as a prelude to spotlight the microbial mechanism and the potential applications of AME-D. Until recently, AME-D was thought to be accomplished by a microbial consortium where denitrifying bacteria utilize carbon intermediates, which are excreted by aerobic methanotrophs, as energy and carbon sources. Potential carbon intermediates include methanol, citrate and acetate. This mini-review presents microbial thermodynamic estimations and postulates that methanol is the ideal electron donor for denitrification, and may serve as a trophic link between methanotrophic bacteria and denitrifiers. More excitingly, new discoveries have revealed that AME-D is not only confined to the conventional synergism between methanotrophic bacteria and denitrifiers. Specifically, an obligate aerobic methanotrophic bacterium, Methylomonas denitrificans FJG1, has been demonstrated to couple partial denitrification with methane oxidation, under hypoxia conditions, releasing nitrous oxide as a terminal product. This finding not only substantially advances the understanding of AME-D mechanism, but also implies an important but unknown role of aerobic methanotrophs in global climate change through their influence on both the methane and nitrogen cycles in ecosystems. Hence, further investigation on AME-D microbiology and mechanism is essential to better understand global climate issues and to develop niche biotechnological solutions. This mini-review also presents traditional microbial techniques, such as pure cultivation and stable isotope probing, and powerful microbial techniques, such as (meta-) genomics and (meta-) transcriptomics, for deciphering linked methane oxidation and denitrification. Although AME-D has immense potential for nitrogen removal from wastewater, drinking

  7. Metagenomics of hydrocarbon resource environments indicates aerobic taxa and genes to be unexpectedly common.

    PubMed

    An, Dongshan; Caffrey, Sean M; Soh, Jung; Agrawal, Akhil; Brown, Damon; Budwill, Karen; Dong, Xiaoli; Dunfield, Peter F; Foght, Julia; Gieg, Lisa M; Hallam, Steven J; Hanson, Niels W; He, Zhiguo; Jack, Thomas R; Klassen, Jonathan; Konwar, Kishori M; Kuatsjah, Eugene; Li, Carmen; Larter, Steve; Leopatra, Verlyn; Nesbø, Camilla L; Oldenburg, Thomas; Pagé, Antoine P; Ramos-Padron, Esther; Rochman, Fauziah F; Saidi-Mehrabad, Alireeza; Sensen, Christoph W; Sipahimalani, Payal; Song, Young C; Wilson, Sandra; Wolbring, Gregor; Wong, Man-Ling; Voordouw, Gerrit

    2013-09-17

    Oil in subsurface reservoirs is biodegraded by resident microbial communities. Water-mediated, anaerobic conversion of hydrocarbons to methane and CO2, catalyzed by syntrophic bacteria and methanogenic archaea, is thought to be one of the dominant processes. We compared 160 microbial community compositions in ten hydrocarbon resource environments (HREs) and sequenced twelve metagenomes to characterize their metabolic potential. Although anaerobic communities were common, cores from oil sands and coal beds had unexpectedly high proportions of aerobic hydrocarbon-degrading bacteria. Likewise, most metagenomes had high proportions of genes for enzymes involved in aerobic hydrocarbon metabolism. Hence, although HREs may have been strictly anaerobic and typically methanogenic for much of their history, this may not hold today for coal beds and for the Alberta oil sands, one of the largest remaining oil reservoirs in the world. This finding may influence strategies to recover energy or chemicals from these HREs by in situ microbial processes.

  8. Metagenomics of Hydrocarbon Resource Environments Indicates Aerobic Taxa and Genes to be Unexpectedly Common

    PubMed Central

    2013-01-01

    Oil in subsurface reservoirs is biodegraded by resident microbial communities. Water-mediated, anaerobic conversion of hydrocarbons to methane and CO2, catalyzed by syntrophic bacteria and methanogenic archaea, is thought to be one of the dominant processes. We compared 160 microbial community compositions in ten hydrocarbon resource environments (HREs) and sequenced twelve metagenomes to characterize their metabolic potential. Although anaerobic communities were common, cores from oil sands and coal beds had unexpectedly high proportions of aerobic hydrocarbon-degrading bacteria. Likewise, most metagenomes had high proportions of genes for enzymes involved in aerobic hydrocarbon metabolism. Hence, although HREs may have been strictly anaerobic and typically methanogenic for much of their history, this may not hold today for coal beds and for the Alberta oil sands, one of the largest remaining oil reservoirs in the world. This finding may influence strategies to recover energy or chemicals from these HREs by in situ microbial processes. PMID:23889694

  9. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    SciTech Connect

    Coyne, P.; Smith, G.

    1995-08-15

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

  10. Biodegradability enhancement of a pesticide-containing bio-treated wastewater using a solar photo-Fenton treatment step followed by a biological oxidation process.

    PubMed

    Vilar, Vítor J P; Moreira, Francisca C; Ferreira, Ana C C; Sousa, M A; Gonçalves, C; Alpendurada, M F; Boaventura, Rui A R

    2012-10-01

    This work proposes an efficient combined treatment for the decontamination of a pesticide-containing wastewater resulting from phytopharmaceutical plastic containers washing, presenting a moderate organic load (COD=1662-1960 mg O₂ L⁻¹; DOC=513-696 mg C L⁻¹), with a high biodegradable organic carbon fraction (81%; BOD₅=1350-1600 mg O₂ L⁻¹) and a remaining recalcitrant organic carbon mainly due to pesticides. Nineteen pesticides were quantified by LC-MS/MS at concentrations between 0.02 and 45 mg L⁻¹ (14-19% of DOC). The decontamination strategy involved a sequential three-step treatment: (a) biological oxidation process, leading to almost complete removal of the biodegradable organic carbon fraction; (b) solar photo-Fenton process using CPCs, enhancing the bio-treated wastewater biodegradability, mainly due to pesticides degradation into low-molecular-weight carboxylate anions; (c) and a final polishing step to remove the residual biodegradable organic carbon, using a biological oxidation process. Treatment performance was evaluated in terms of mineralization degree (DOC), pesticides content (LC-MS/MS), inorganic ions and low-molecular-weight carboxylate anions (IC) concentrations. The estimated phototreatment energy necessary to reach a biodegradable wastewater, considering pesticides and low-molecular-weight carboxylate anions concentrations, Zahn-Wellens test and BOD₅/COD ratio, was only 2.3 kJ(UV) L⁻¹ (45 min of photo-Fenton at a constant solar UV power of 30 W m⁻²), consuming 16 mM of H₂O₂, which pointed to 52% mineralization and an abatement higher than 86% for 18 pesticides. The biological oxidation/solar photo-Fenton/biological oxidation treatment system achieved pesticide removals below the respective detection limits and 79% mineralization, leading to a COD value lower than 150 mg O₂ L⁻¹, which is in agreement with Portuguese discharge limits regarding water bodies.

  11. Reductive dechlorination of trichloroethylene and tetrachloroethylene under aerobic conditions in a sediment column

    SciTech Connect

    Enzien, M.V.; Picardal, F.; Hazen, T.

    1994-06-01

    This study investigated the bioremediation of chlorinated solvents in a sediment column. Biodegradation potentials of trichloroethylene and tetrachloroethylene during aerobic methanotrophic biostimulation were studied at the Savannah River Site. 30 refs., 3 figs., 3 tabs.

  12. Evaluation of trichloroethene recovery processes in heterogeneous aquifer cells flushed with biodegradable surfactants

    NASA Astrophysics Data System (ADS)

    Suchomel, Eric J.; Ramsburg, C. Andrew; Pennell, Kurt D.

    2007-12-01

    The ability of two biodegradable surfactants, polyoxyethylene (20) sorbitan monooleate (Tween® 80) and sodium dihexyl sulfosuccinate (Aerosol® MA), to recover a representative dense non-aqueous-phase liquid (DNAPL), trichloroethene (TCE), from heterogeneous porous media was evaluated through a combination of batch and aquifer cell experiments. An aqueous solution containing 3.3% Aerosol MA, 8% 2-propanol and 6 g/l CaCl 2 yielded a weight solubilization ratio (WSR) of 1.21 g TCE/g surfactant, with a corresponding liquid-liquid interfacial tension (IFT) of 0.19 dyn/cm. Flushing of aquifer cells containing a TCE-DNAPL source zone with approximately two pore volumes of the AMA formulation resulted in substantial (> 30%) mobilization of TCE-DNAPL. However, a TCE mass recovery of 81% was achieved when the aqueous-phase flow rate was sufficient to displace the mobile TCE-DNAPL toward the effluent well. Aqueous solutions of Tween 80 exhibited a greater capacity to solubilize TCE (WSR = 1.74 g TCE/g surfactant) and exerted markedly less reduction in IFT (10.4 dyn/cm). These data contradict an accepted empirical correlation used to estimate IFT values from solubilization capacity, and indicate a unique capacity of T80 to form concentrated TCE emulsions. Flushing of aquifer cells with less than 2.5 pore volumes of a 4% T80 solution achieved TCE mass recoveries ranging from 66 to 85%, with only slight TCE-DNAPL mobilization (< 5%) occurring when the total trapping number exceeded 2 × 10 - 5 . These findings demonstrate the ability of Tween 80 and Aerosol MA solutions to efficiently recover TCE from a heterogeneous DNAPL source zone, and the utility of the total trapping number as a design parameter for a priori prediction of DNAPL mobilization and bank angle formation when flushing with low-IFT solutions. Given their potential to stimulate microbial reductive dechlorination at low concentrations, these surfactants are well-suited for remedial action plans that couple

  13. Toward a novel membrane process for organic carbon removal-fate of slowly biodegradable substrate in super fast membrane bioreactor.

    PubMed

    Sözen, S; Teksoy Başaran, S; Akarsubaşı, A; Ergal, I; Insel, G; Karaca, C; Orhon, D

    2016-08-01

    The study tested the performance of super fast membrane bioreactor (SFMBR) using starch as a slowly biodegradable substrate, exploring the fate of starch, and the response of the microbial community. SFMBR was operated at extremely low sludge ages of 0.5-2.0 days, with a hydraulic retention time of 1.0 h. Average values for permeate chemical oxygen demand (COD) always remained in the narrow range between 14 and 18 mg/L, regardless of the selected mode of MBR operation at different sludge ages. Soluble COD levels in the reactor were consistently higher than the corresponding permeate COD. Parameters defining process kinetics, determined by model calibration of oxygen uptake rate (OUR) profiles, varied as a function of sludge age. Model simulation of SFMBR performance indicated total removal of hydrolysis products so that permeate COD consisted of residual microbial products. PCR-DGGE experiments revealed significant shifts in the composition of the microbial community imposed by variations in the sludge age, reflecting on corresponding process kinetics.

  14. Crude-oil biodegradation via methanogenesis in subsurface petroleum reservoirs.

    PubMed

    Jones, D M; Head, I M; Gray, N D; Adams, J J; Rowan, A K; Aitken, C M; Bennett, B; Huang, H; Brown, A; Bowler, B F J; Oldenburg, T; Erdmann, M; Larter, S R

    2008-01-10

    Biodegradation of crude oil in subsurface petroleum reservoirs has adversely affected the majority of the world's oil, making recovery and refining of that oil more costly. The prevalent occurrence of biodegradation in shallow subsurface petroleum reservoirs has been attributed to aerobic bacterial hydrocarbon degradation stimulated by surface recharge of oxygen-bearing meteoric waters. This hypothesis is empirically supported by the likelihood of encountering biodegraded oils at higher levels of degradation in reservoirs near the surface. More recent findings, however, suggest that anaerobic degradation processes dominate subsurface sedimentary environments, despite slow reaction kinetics and uncertainty as to the actual degradation pathways occurring in oil reservoirs. Here we use laboratory experiments in microcosms monitoring the hydrocarbon composition of degraded oils and generated gases, together with the carbon isotopic compositions of gas and oil samples taken at wellheads and a Rayleigh isotope fractionation box model, to elucidate the probable mechanisms of hydrocarbon degradation in reservoirs. We find that crude-oil hydrocarbon degradation under methanogenic conditions in the laboratory mimics the characteristic sequential removal of compound classes seen in reservoir-degraded petroleum. The initial preferential removal of n-alkanes generates close to stoichiometric amounts of methane, principally by hydrogenotrophic methanogenesis. Our data imply a common methanogenic biodegradation mechanism in subsurface degraded oil reservoirs, resulting in consistent patterns of hydrocarbon alteration, and the common association of dry gas with severely degraded oils observed worldwide. Energy recovery from oilfields in the form of methane, based on accelerating natural methanogenic biodegradation, may offer a route to economic production of difficult-to-recover energy from oilfields.

  15. Biodegradation of propellant ingredients

    SciTech Connect

    Zhang, Y.Z.; Sundaram, S.T.; Sharma, A.

    1995-12-31

    This paper summarizes efforts to degrade nitrocellulose (NC) and nitroglycerin (NG) with fungi. Screening experiments were performed to determine the ability of mycelial fungi to biodegrade NC. The greatest amount of NC degradation was obtained with Sclerotium rolfsii ATCC 24459 and Fusarium solani IFO 31093. These fungi were then tested for NG degradation. It was found that the combined culture aerobically degraded 100% of the NG to form a mixture of 55% dinitroglycerin (DNG) and 5% of mononitroglycerin (MNG) in two days, with no further change observed afterward. In the presence of 1.2% glucose and 0.05% ammonium nitrate, NG was completely degraded in two days and a mixture of 20% DNG and 16% MNG was formed after 11 days. Based on these results, it appears that the combination of the fungi in a one to one ratio can be used to degrade both of these energetic compounds.

  16. Degradation and biodegradability improvement of the olive mill wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes.

    PubMed

    Esfandyari, Yahya; Mahdavi, Yousef; Seyedsalehi, Mahdi; Hoseini, Mohammad; Safari, Gholam Hossein; Ghozikali, Mohammad Ghanbari; Kamani, Hossein; Jaafari, Jalil

    2015-04-01

    Olive mill wastewater is considered as one of the most polluting effluents of the food industry and constitutes a source of important environmental problems. In this study, the removal of pollutants (chemical oxygen demand (COD), biochemical oxygen demand (BOD5), polyphenols, turbidity, color, total suspended solids (TSS), and oil and grease) from olive oil mill processing wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes was evaluated using a pilot continuous reactor. In the electrochemical unit, aluminum (Al), stainless steel, and RuO2/Ti plates were used. The effects of pH, hydrogen peroxide doses, current density, NaCl concentrations, and reaction times were studied. Under optimal conditions of pH 4, current density of 40 mA/m(2), 1000 mg/L H2O2, 1 g/L NaCl, and 30-min reaction time, the peroxi-electrochemical method yielded very effective removal of organic pollution from the olive mill wastewater diluted four times. The treatment process reduced COD by 96%, BOD5 by 93.6%, total, polyphenols by 94.4%, color by 91.4%, turbidity by 88.7, suspended solids by 97% and oil and grease by 97.1%. The biodegradability index (BOD5/COD) increased from 0.29 to 0.46. Therefore, the peroxi-electrocoagulation/electrooxidation-electroflotation process is considered as an effective and feasible process for pre-treating olive mill wastewater, making possible a post-treatment of the effluent in a biological system.

  17. Ecotoxicity by the biodegradation of alkylphenol polyethoxylates depends on the effect of trace elements.

    PubMed

    Hotta, Yudai; Hosoda, Akifumi; Sano, Fumihiko; Wakayama, Manabu; Niwa, Katsuki; Yoshikawa, Hiromichi; Tamura, Hiroto

    2010-01-27

    The bacteria Sphingomonas sp. strain BSN22, isolated from bean fields, degraded octylphenol polyethoxylates (OPEO(n)) to octylphenol (OP) under aerobic conditions. This biodegradation mechanism proceeded by the following two-step degradation process: (1) degradation of OPEO(n) to octylphenol triethoxylate (OPEO(3)), (2) degradation from OPEO(3) to OP via octylphenoxy acetic acid (OPEC(1)). The chemical structure of OPEC(1) was confirmed by analysis using (18)O-labeled water. Quantitative studies revealed that magnesium (Mg(2+)) and calcium (Ca(2+)) ions were essential for the biodegradation of OPEO(n). Furthermore, the rate of biodegradation was especially accelerated by ferric ions (Fe(3+)), and the accumulated amounts of endocrine active chemicals, such as OP, OPEO(1), and OPEC(1), significantly increased to the concentration of 22.8, 221.7, and 961.1 microM in the presence of 37.0 microM Fe(3+), respectively. This suggests that environmental elements significantly influence the resultant ecotoxicity as well as the rate of their biodegradation in the environment. This study on the mechanism of OPEO(n) biodegradation may play an important role in understanding and managing environmental safety, including drinking water safety.

  18. Characterization of landfill leachates by molecular size distribution, biodegradability, and inert chemical oxygen demand.

    PubMed

    Amaral, Míriam C S; Ferreira, Cynthia F A; Lange, Liséte Celina; Aquino, Sérgio F

    2009-05-01

    This work presents results from a detailed characterization of landfill leachates of different ages from a landfill in a major Brazilian city. This characterization consists of determining the molecular size distribution and the inert chemical oxygen demand (COD) and the biodegradability of both aerobic and anaerobic processes. Results show that leachate with a high COD concentration leachate has low biodegradability. A significant fraction of the COD is not characterized as protein, carbohydrate, or lipids, which reinforces the hypothesis that the remaining fraction was present in all leachate fractions (less than 1 kDa; between 1 and 10 kDa; between 10 and 100 kDa; and greater than 100 kDa) and is refractory. These results suggest that leachates with such characteristics require treatment systems that use physical-chemical processes as a pre- or post-treatment step to biological processes.

  19. Biodegradation of chlorinated ethenes at a karst site in middle Tennessee

    USGS Publications Warehouse

    Byl, Thomas Duane; Williams, Shannon D.

    2000-01-01

    This report presents results of field and laboratory investigations examining the biodegradation of chlorinated ethenes in a karst aquifer contaminated with trichloroethylene (TCE). The study site, located in Middle Tennessee, was selected because of the presence of TCE degradation byproducts in the karst aquifer and available site hydrologic and chlorinated-ethene information. Additional chemical, biological, and hydrologic data were gathered to evaluate whether the occurrence of TCE degradation byproducts in the karst aquifer was the result of biodegradation within the aquifer or simply transport into the aquifer. Geochemical analysis established that sulfate-reducing conditions, essential for reductive dechlorination of chlorinated solvents, existed in parts of the contaminated karst aquifer. Other areas of the aquifer fluctuated between anaerobic and aerobic conditions and contained compounds associated with cometabolism, such as ethane, methane, ammonia, and dissolved oxygen. A large, diverse bacteria population inhabits the contaminated aquifer. Bacteria known to biodegrade TCE and other chlorinated solvents, such as sulfate-reducers, methanotrophs, and ammonia-oxidizers, were identified from karst-aquifer water using the RNA-hybridization technique. Results from microcosms using raw karst-aquifer water found that aerobic cometabolism and anaerobic reductive-dechlorination degradation processes were possible when appropriate conditions were established in the microcosms. These chemical and biological results provide circumstantial evidence that several biodegradation processes are active in the aquifer. Additional site hydrologic information was developed to determine if appropriate conditions persist long enough in the karst aquifer for these biodegradation processes to be significant. Continuous monitoring devices placed in four wells during the spring of 1998 indicated that pH, specific conductance, dissolved oxygen, and oxidation-reduction potentials

  20. Organic micropollutants in aerobic and anaerobic membrane bioreactors: Changes in microbial communities and gene expression.

    PubMed

    Harb, Moustapha; Wei, Chun-Hai; Wang, Nan; Amy, Gary; Hong, Pei-Ying

    2016-10-01

    Organic micro-pollutants (OMPs) are contaminants of emerging concern in wastewater treatment due to the risk of their proliferation into the environment, but their impact on the biological treatment process is not well understood. The purpose of this study is to examine the effects of the presence of OMPs on the core microbial populations of wastewater treatment. Two nanofiltration-coupled membrane bioreactors (aerobic and anaerobic) were subjected to the same operating conditions while treating synthetic municipal wastewater spiked with OMPs. Microbial community dynamics, gene expression levels, and antibiotic resistance genes were analyzed using molecular-based approaches. Results showed that presence of OMPs in the wastewater feed had a clear effect on keystone bacterial populations in both the aerobic and anaerobic sludge while also significantly impacting biodegradation-associated gene expression levels. Finally, multiple antibiotic-type OMPs were found to have higher removal rates in the anaerobic MBR, while associated antibiotic resistance genes were lower.

  1. 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.

  2. Aerobic biological treatment of leachates from municipal solid waste landfill.

    PubMed

    Andrés, P; Gutierrez, F; Arrabal, C; Cortijo, M

    2004-01-01

    The main objective of the study was to improve chemical oxygen demand (COD) elimination by secondary biological treatment from leachate of municipal solid waste landfill. This effluent was a supernatant liquid obtained after physicochemical processes and coagulating with Al3+ followed by ammoniacal stripping. First, respirometric assays were carried out to determine the substrate biodegradability. Specific sludge respiration rate (R(s)) vs. concentration of substrate (S), showed an increasing specific rate of assimilation of substrate (Rs), which reached the highest value, when the substrate concentration (COD) was between 75 and 200 mg O2 L(-1). Second, continuous experiments were made in an aerobic digester to test the previous respirometric data and the results showed removal efficiency of COD between 83 and 69%, and a substrate assimilation rate between 1.3 and 3.1 g COD g(-1) volatile suspended solids d(-1).

  3. Analysis and toxicity of methomyl and ametryn after biodegradation.

    PubMed

    Farré, M; Fernandez, J; Paez, M; Granada, L; Barba, L; Gutierrez, H M; Pulgarin, C; Barceló, D

    2002-04-01

    The controlled biodegradation of ametryn and methomyl has been performed, in accordance with the OECD Zahn-Wellens/EMPA procedure, by use of an enriched mixture of activated sludge collected from three domestic waste-water-treatment plants (WWTP). During the process concentrations of ametryn and methomyl in the water samples were isolated by solid-phase extraction (SPE); recovery rates were 98.9 and 93.2 for methomyl and ametryn, respectively. Liquid chromatography-mass spectrometry (LC-MS) was used to determine final pesticide concentrations and for metabolite identification. The efficiency of aerobic biodegradation of ametryn and methomyl was evaluated by measuring both the decrease in the concentration of the pesticides and global properties such as the chemical oxygen demand (COD). The acute toxicity of ametryn and methomyl was evaluated by use of the ToxAlert100 biological test, which is based on inhibition of the bioluminescence of Vibrio fischeri. There was significant correlation between results from primary and ultimate biodegradation and those from determination of toxicity. Pesticide concentrations were always reduced to below the limit of detection in less than 17 days. High COD removal (90-96%) was achieved in 28 and 18 days for methomyl and ametryn, respectively.

  4. Relating Carbon and Nitrogen Isotope Effects to Reaction Mechanisms during Aerobic or Anaerobic Degradation of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine) by Pure Bacterial Cultures

    PubMed Central

    Heraty, Linnea; Condee, Charles W.; Vainberg, Simon; Sturchio, Neil C.; Böhlke, J. K.; Hatzinger, Paul B.

    2016-01-01

    ABSTRACT Kinetic isotopic fractionation of carbon and nitrogen during RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) biodegradation was investigated with pure bacterial cultures under aerobic and anaerobic conditions. Relatively large bulk enrichments in 15N were observed during biodegradation of RDX via anaerobic ring cleavage (ε15N = −12.7‰ ± 0.8‰) and anaerobic nitro reduction (ε15N = −9.9‰ ± 0.7‰), in comparison to smaller effects during biodegradation via aerobic denitration (ε15N = −2.4‰ ± 0.2‰). 13C enrichment was negligible during aerobic RDX biodegradation (ε13C = −0.8‰ ± 0.5‰) but larger during anaerobic degradation (ε13C = −4.0‰ ± 0.8‰), with modest variability among genera. Dual-isotope ε13C/ε15N analyses indicated that the three biodegradation pathways could be distinguished isotopically from each other and from abiotic degradation mechanisms. Compared to the initial RDX bulk δ15N value of +9‰, δ15N values of the NO2− released from RDX ranged from −7‰ to +2‰ during aerobic biodegradation and from −42‰ to −24‰ during anaerobic biodegradation. Numerical reaction models indicated that N isotope effects of NO2− production were much larger than, but systematically related to, the bulk RDX N isotope effects with different bacteria. Apparent intrinsic ε15N-NO2− values were consistent with an initial denitration pathway in the aerobic experiments and more complex processes of NO2− formation associated with anaerobic ring cleavage. These results indicate the potential for isotopic analysis of residual RDX for the differentiation of degradation pathways and indicate that further efforts to examine the isotopic composition of potential RDX degradation products (e.g., NOx) in the environment are warranted. IMPORTANCE This work provides the first systematic evaluation of the isotopic fractionation of carbon and nitrogen in the organic explosive RDX during degradation by different pathways. It also

  5. Sustained release of risperidone from biodegradable microspheres prepared by in-situ suspension-evaporation process.

    PubMed

    An, Taekun; Choi, Juhyuen; Kim, Aram; Lee, Jin Ho; Nam, Yoonjin; Park, Junsung; Sun, Bo kyung; Suh, Hearan; Kim, Cherng-ju; Hwang, Sung-Joo

    2016-04-30

    Risperidone-loaded poly (D,L-lactide-co-glycolide) (PLGA) microspheres were prepared with a suspension-evaporation process with an aqueous suspension containing an in situ-formed aluminum hydroxide inorganic gel (SEP-AL process) and evaluated for encapsulation efficiency, particle size, surface morphology, glass transition temperature, in vitro drug release profile, and in vivo behavior. The SEP-AL microspheres were compared with conventional oil-in-water (O/W) emulsion solvent evaporation method using polyvinylalcohol (PVA) as an emulsifier (CP-PVA process). The microspheres were spherical in shape. DSC measurements showed that risperidone crystallinity was greatly reduced due to the homogeneous distribution of risperidone in PLGA microspheres. In vitro drug release profile from the microspheres showed a sigmoidal pattern of negligible initial burst up to 24h and minimal release (time-lag) for 7 days. After the lag phase, slow release took a place up to 25 days and then rapid release occurred sharply for 1 week. In vivo rat pharmacokinetic profile from the microspheres showed very low blood concentration level at the initial phase (up to 24h) followed by the latent phase up to 21 days. At the 3rd week, main phase started and the blood concentration of the drug increased up to the 5th week, and then gradually decreased. The risperidone-loaded PLGA microspheres produced by SEP-AL process showed excellent controlled release characteristics for the effective treatment of schizophrenia patients.

  6. Systemic approaches to biodegradation.

    PubMed

    Trigo, Almudena; Valencia, Alfonso; Cases, Ildefonso

    2009-01-01

    Biodegradation, the ability of microorganisms to remove complex chemicals from the environment, is a multifaceted process in which many biotic and abiotic factors are implicated. The recent accumulation of knowledge about the biochemistry and genetics of the biodegradation process, and its categorization and formalization in structured databases, has recently opened the door to systems biology approaches, where the interactions of the involved parts are the main subject of study, and the system is analysed as a whole. The global analysis of the biodegradation metabolic network is beginning to produce knowledge about its structure, behaviour and evolution, such as its free-scale structure or its intrinsic robustness. Moreover, these approaches are also developing into useful tools such as predictors for compounds' degradability or the assisted design of artificial pathways. However, it is the environmental application of high-throughput technologies from the genomics, metagenomics, proteomics and metabolomics that harbours the most promising opportunities to understand the biodegradation process, and at the same time poses tremendous challenges from the data management and data mining point of view.

  7. Is artificial recharge promoting microbial activity and biodegradation processes in groundwater systems?

    NASA Astrophysics Data System (ADS)

    Barba Ferrer, Carme; Folch, Albert; Gaju, Núria; Martínez-Alonso, Maira; Carrasquilla, Marc; Grau-Martínez, Alba; Sanchez-Vila, Xavier

    2016-04-01

    Managed Artificial Recharge (MAR) represents a strategic tool for managing water resources, especially during scarce periods. On one hand, it can increase water stored in aquifers and extract it when weather conditions do not permit exclusive exploitation of surface resources. On the other, it allows improve water quality due the processes occurring into the soil whereas water crosses vadose zone. Barcelona (Catalonia, Spain) conurbation is suffering significant quantitative and qualitative groundwater disturbances. For this reason, Sant Vicenç MAR system, constituted by a sedimentation and an infiltration pond, was constructed in 2009 as the strategic water management infrastructure. Compared with other MAR facilities, this infiltration pond has a reactive bed formed by organic compost and local material. The objective is to promote different redox states allowing more and different degradation of chemical compounds than regular MAR systems. In previous studies in the site, physical and hydrochemical parameters demonstrated that there was indeed a degradation of different pollutants. However, to go a step further understanding the different biogeochemical processes and the related degradation processes occurring in the system, we studied the existing microbial communities. So, molecular techniques were applied in water and soil samples in two different scenarios; the first one, when the system was fully operating and the second when the system was not operating during some months. We have specifically compared microbial diversity and richness indexes and both cluster dendrograms obtained from DGGEs analysis made in each sampling campaign.

  8. BIODEGRADATION OF SEDIMENT-BOUND PAHS IN FIELD-CONTAMINATED SEDIMENT

    EPA Science Inventory

    The biodegradation of polycyclic aromatic hydrocarbons (PAHs) has been reported to occur under aerobic, sulfate reducing, and denitrifying conditions. PAHs present in contaminated sites, however, are known for their persistence. Most published studies were conducted in systems wh...

  9. Microbial Degradation of Poly-B-esters: a Mechanistic Study, Cellulose Acetate Biodegradability

    DTIC Science & Technology

    1993-08-30

    enzyme specificity and activity, (3) isolation, purification and characterization of cellulose acetate degrading microorganisms and (4) determination...of the biodegradability of cellulose acetate with degrees of substitution up to 2.5 under aerobic thermophilic conditions.

  10. Combined mesophilic anaerobic and thermophilic aerobic digestion process for high-strength food wastewater to increase removal efficiency and reduce sludge discharge.

    PubMed

    Jang, H M; Park, S K; Ha, J H; Park, J M

    2014-01-01

    In this study, a process that combines the mesophilic anaerobic digestion (MAD) process with thermophilic aerobic digestion (TAD) for high-strength food wastewater (FWW) treatment was developed to examine the removal of organic matter and methane production. All effluent discharged from the MAD process was separated into solid and liquid portions. The liquid part was discarded and the sludge part was passed to the TAD process for further degradation. Then, the digested sludge from the TAD process was recycled back to the MAD unit to achieve low sludge discharge from the combined process. The reactor combination was operated in two phases: during Phase I, 40 d of total hydraulic retention time (HRT) was applied; during Phase II, 20 d was applied. HRT of the TAD process was fixed at 5 d. For a comparison, a control process (single-stage MAD) was operated with the same HRTs of the combined process. Our results indicated that the combined process showed over 90% total solids, volatile solids and chemical oxygen demand removal efficiencies. In addition, the combined process showed a significantly higher methane production rate than that of the control process. Consequently, the experimental data demonstrated that the combined MAD-TAD process was successfully employed for high-strength FWW treatment with highly efficient organic matter reduction and methane production.

  11. A new application of passive samplers as indicators of in-situ biodegradation processes.

    PubMed

    Belles, Angel; Alary, Claire; Criquet, Justine; Billon, Gabriel

    2016-12-01

    In this paper, a method for evaluating the in-situ degradation of nitro polycyclic aromatic hydrocarbons (nitro-PAH) in sediments is presented. The methodology is adapted from the passive sampler technique, which commonly uses the dissipation rate of labeled compounds loaded in passive sampler devices to sense the environmental conditions of exposure. In the present study, polymeric passive samplers (made of polyethylene strips) loaded with a set of labeled polycyclic aromatic hydrocarbons (PAH) and nitro-PAH were immersed in sediments (in field and laboratory conditions) to track the degradation processes. This approach is theoretically based on the fact that a degradation process induces a steeper concentration gradient of the labeled compounds in the surrounding sediment, thereby increasing their compound dissipation rates compared with their dissipation in abiotic conditions. Postulating that the degradation magnitude is the same for the labeled compounds loaded in polyethylene strips and for their native homologs that are potentially present in the sediment, the field degradation of 3 nitro-PAH (2-nitro-fluorene, 1-nitro-pyrene, 6-nitro-chrysene) was semi-quantitatively analyzed using the developed method.

  12. A numerical investigation of oxygen concentration dependence on biodegradation rate laws in vapor intrusion.

    PubMed

    Yao, Yijun; Shen, Rui; Pennel, Kelly G; Suuberg, Eric M

    2013-12-01

    In subsurface vapor intrusion, aerobic biodegradation has been considered as a major environmental factor that determines the soil gas concentration attenuation factors for contaminants such as petroleum hydrocarbons. The site investigation has shown that oxygen can play an important role in this biodegradation rate, and this paper explores the influence of oxygen concentration on biodegradation reactions included in vapor intrusion (VI) models. Two different three dimensional (3-D) numerical models of vapor intrusion were explored for their sensitivity to the form of the biodegradation rate law. A second order biodegradation rate law, explicitly including oxygen concentration dependence, was introduced into one model. The results indicate that the aerobic/anoxic interface depth is determined by the ratio of contaminant source vapor to atmospheric oxygen concentration, and that the contaminant concentration profile in the aerobic zone was significantly influenced by the choice of rate law.

  13. Impact of glycerin and lignosulfonate on biodegradation of high explosives in soil

    NASA Astrophysics Data System (ADS)

    Won, Jongho; Borden, Robert C.

    2016-11-01

    Soil microcosms were constructed and monitored to evaluate the impact of substrate addition and transient aerobic and anaerobic conditions on TNT, RDX and HMX biodegradation in grenade range soils. While TNT was rapidly biodegraded under both aerobic and anaerobic conditions with and without organic substrate, substantial biodegradation of RDX, HMX, and RDX daughter products was not observed under aerobic conditions. However, RDX and HMX were significantly biodegraded under anaerobic conditions, without accumulation of TNT or RDX daughter products (2-ADNT, 4-ADNT, MNX, DNX, and TNX). In separate microcosms containing grenade range soil, glycerin and lignosulfonate addition enhanced oxygen consumption, increasing the consumption rate > 200% compared to untreated soils. Mathematical model simulations indicate that oxygen consumption rates of 5 to 20 g/m3/d can be achieved with reasonable amendment loading rates. These results indicate that glycerin and lignosulfonate can be potentially used to stimulate RDX and HMX biodegradation by increasing oxygen consumption rates in soil.

  14. A numerical investigation of oxygen concentration dependence on biodegradation rate laws in vapor intrusion

    PubMed Central

    Yao, Yijun; Shen, Rui; Pennel, Kelly G.; Suuberg, Eric M.

    2013-01-01

    In subsurface vapor intrusion, aerobic biodegradation has been considered as a major environmental factor that determines the soil gas concentration attenuation factors for contaminants such as petroleum hydrocarbons. The site investigation showed that oxygen could play an important role in this biodegradation rate, and this paper explores the influence of oxygen concentration in biodegradation reactions included in vapor intrusion (VI) models. Two different three dimensional (3-D) numerical models of vapor intrusion were explored for their sensitivity to the form of the biodegradation rate law. A second order biodegradation rate law, explicitly including oxygen concentration dependence, was introduced into one model. The results indicate that the aerobic/anoxic interface depth is determined by the ratio of contaminant source vapor to atmospheric oxygen concentration, and that the contaminant concentration profile in the aerobic zone was significantly influenced by the choice of rate law. PMID:24197079

  15. Identification of Biodegradation Pathways in a Multi-Process Phytoremediation System (MPPS) Using Natural Abundance 14C Analysis of PLFA

    NASA Astrophysics Data System (ADS)

    Cowie, B. R.; Greenberg, B. M.; Slater, G. F.

    2008-12-01

    Optimizing remediation of petroleum-contaminated soils requires thorough understanding of the mechanisms and pathways involved in a proposed remediation system. In many engineered and natural attenuation systems, multiple degradation pathways may contribute to observed contaminant mass losses. In this study, biodegradation in the soil microbial community was identified as a major pathway for petroleum hydrocarbon removal in a Multi-Process Phytoremediation System (MPPS) using natural abundance 14C analysis of Phospholipid Fatty Acids (PLFA). In contaminated soils, PLFA were depleted in Δ14C to less than -800‰, directly demonstrating microbial uptake and utilization of petroleum derived carbon (Δ14C = -992‰) during bioremediation. Mass balance indicated that more than 80% of microbial carbon was derived from petroleum hydrocarbons and a maximum of 20% was produced from metabolism of modern carbon sources. In contrast, in a nearby uncontaminated control soil, the microbial community maintained a nearly modern 14C signature, suggesting preferential degradation of more labile, recent carbon. Mass balance using δ13C and Δ14C of soil CO2 demonstrated that mineralization of petroleum carbon contributed 60-65% of soil CO2 at the contaminated site. The remainder was derived from atmospheric (27-30%) and decomposition of non- petroleum natural organic carbon (5-10%). The clean control exhibited substantially lower CO2 concentrations that were derived from atmospheric (55%) and natural organic carbon (45%) sources. This study highlights the value of using multiple carbon isotopes to identify degradation pathways in petroleum- contaminated soils undergoing phytoremediation and the power of natural abundance 14C to detect petroleum metabolism in natural microbial communities.

  16. A simple recovery process for biodegradable plastics accumulated in cyanobacteria treated with ionic liquids.

    PubMed

    Kobayashi, Daigo; Fujita, Kyoko; Nakamura, Nobuhumi; Ohno, Hiroyuki

    2015-02-01

    Here, we proposed a simple recovery process for poly(3-hydroxybutyrate) (PHB) accumulated in cyanobacteria by using ionic liquids (ILs), which dissolve cyanobacteria but not PHB. First, we investigated the effects of IL polarity on hydrogen-bonding receipt ability (β value) and hydrogen-bonding donating ability (α value) and evaluated the subsequent dissolution of cyanobacteria. We found that ILs having α values higher than approximately 0.4 and β values of approximately 0.9 were suitable for dissolution of cyanobacteria. In particular, 1-ethyl-3-methylimidazolium methylphosphonate ([C2mim][MeO(H)PO2]) was found to dissolve cyanobacteria components, but not PHB. Thus, we verified that PHB produced in cyanobacteria could be separated and recovered by simple filtering after dissolution of cyanobacteria in [C2mim][MeO(H)PO2]. Using this technique, more than 98 % of PHB was obtained on the filter as residues separated from cyanobacteria. Furthermore, [C2mim][MeO(H)PO2] maintained the ability to dissolve cyanobacteria after a simple recycling procedure.

  17. Characterization of organic particulates present in milk factory process waters used for reuse along with aerobically digested effluent wastewater.

    PubMed

    Verheyen, Vincent; Cruickshank, Alicia; Wild, Karl; Heaven, Michael W; McGee, Rachel; Watkins, Mark; Nash, David

    2011-01-01

    Wastewater from a dairy processor is being reused and recycled both within the plant and for irrigation. Flash pyrolysis GC-MS was used to examine nitrogen and phenol containing compounds (M.W.=35 to 450 g/mol) in the particulate fraction of the milk condensate, combined clean wastewater and aerobic bioreactor effluent. For comparison, the particulates were also prepared for standard GC-MS analyses using conventional solvent extraction methods. Compounds detected by pyrolysis GC-MS were found mostly in the bioreactor with the amino acid arginine (220 mg/kg) and the amino acid derivative 1-methyl-5-oxo-L-proline methyl ester (130 mg/kg) found at the highest concentrations. In comparison, sterols detected in the effluent were found at higher concentrations when using solvent extraction indicating some degradation with pyrolysis GC-MS. However, with few exceptions, particulates were generally found not to act as passive collectors capable of concentrating less water soluble chemicals.

  18. Biodegradable polydepsipeptides.

    PubMed

    Feng, Yakai; Guo, Jintang

    2009-02-01

    This paper reviews the synthesis, characterization, biodegradation and usage of bioresorbable polymers based on polydepsipeptides. The ring-opening polymerization of morpholine-2,5-dione derivatives using organic Sn and enzyme lipase is discussed. The dependence of the macroscopic properties of the block copolymers on their structure is also presented. Bioresorbable polymers based on polydepsipeptides could be used as biomaterials in drug controlled release, tissue engineering scaffolding and shape-memory materials.

  19. Biodegradation of corrosion inhibitors and their influence on petroleum product pipeline.

    PubMed

    Rajasekar, Aruliah; Maruthamuthu, Sundaram; Palaniswamy, Narayanan; Rajendran, Annamalai

    2007-01-01

    The present study enlightens the role of Bacillus cereus ACE4 on biodegradation of commercial corrosion inhibitors (CCI) and the corrosion process on API 5LX steel. Bacillus cereus ACE4, a dominant facultative aerobic species was identified by 16S rDNA sequence analysis, which was isolated from the corrosion products of refined diesel-transporting pipeline in North West India. The effect of CCI on the growth of bacterium and its corrosion inhibition efficiency were investigated. Corrosion inhibition efficiency was studied by rotating cage test and the nature of biodegradation of corrosion inhibitors was also analyzed. This isolate has the capacity to degrade the aromatic and aliphatic hydrocarbon present in the corrosion inhibitors. The degraded products of corrosion inhibitors and bacterial activity determine the electrochemical behavior of API 5LX steel.

  20. Biodegradation aspects of polycyclic aromatic hydrocarbons (PAHs): a review.

    PubMed

    Haritash, A K; Kaushik, C P

    2009-09-30

    PAHs are aromatic hydrocarbons with two or more fused benzene rings with natural as well as anthropogenic sources. They are widely distributed environmental contaminants that have detrimental biological effects, toxicity, mutagenecity and carcinogenicity. Due to their ubiquitous occurrence, recalcitrance, bioaccumulation potential and carcinogenic activity, the PAHs have gathered significant environmental concern. Although PAH may undergo adsorption, volatilization, photolysis, and chemical degradation, microbial degradation is the major degradation process. PAH degradation depends on the environmental conditions, number and type of the microorganisms, nature and chemical structure of the chemical compound being degraded. They are biodegraded/biotransformed into less complex metabolites, and through mineralization into inorganic minerals, H(2)O, CO(2) (aerobic) or CH(4) (anaerobic) and rate of biodegradation depends on pH, temperature, oxygen, microbial population, degree of acclimation, accessibility of nutrients, chemical structure of the compound, cellular transport properties, and chemical partitioning in growth medium. A number of bacterial species are known to degrade PAHs and most of them are isolated from contaminated soil or sediments. Pseudomonas aeruginosa, Pseudomons fluoresens, Mycobacterium spp., Haemophilus spp., Rhodococcus spp., Paenibacillus spp. are some of the commonly studied PAH-degrading bacteria. Lignolytic fungi too have the property of PAH degradation. Phanerochaete chrysosporium, Bjerkandera adusta, and Pleurotus ostreatus are the common PAH-degrading fungi. Enzymes involved in the degradation of PAHs are oxygenase, dehydrogenase and lignolytic enzymes. Fungal lignolytic enzymes are lignin peroxidase, laccase, and manganese peroxidase. They are extracellular and catalyze radical formation by oxidation to destabilize bonds in a molecule. The biodegradation of PAHs has been observed under both aerobic and anaerobic conditions and the rate

  1. Effects of organic loading rates on reactor performance and microbial community changes during thermophilic aerobic digestion process of high-strength food wastewater.

    PubMed

    Jang, Hyun Min; Lee, Jae Won; Ha, Jeong Hyub; Park, Jong Moon

    2013-11-01

    To evaluate the applicability of single-stage thermophilic aerobic digestion (TAD) process treating high-strength food wastewater (FWW), TAD process was operated at four organic loading rates (OLRs) from 9.2 to 37.2 kg COD/m(3)d. The effects of OLRs on microbial community changes were also examined. The highest volumetric removal rate (13.3 kg COD/m(3)d) and the highest thermo-stable protease activity (0.95 unit/mL) were detected at OLR=18.6 kg COD/m(3)d. Denaturing gradient gel electrophoresis (DGGE) profiles and quantitative PCR (qPCR) results showed significant microbial community shifts in response to changes in OLR. In particular, DGGE and phylogenetic analysis demonstrate that the presence of Bacillus sp. (phylum of Firmicutes) was strongly correlated with efficient removal of organic particulates from high-strength food wastewater.

  2. An integrated anaerobic/aerobic bioprocess for the remediation of chlorinated phenol-contaminated soil and groundwater.

    PubMed

    Ehlers, George A; Rose, Peter D

    2006-07-01

    An investigation of biodegradation of chlorinated phenol in an anaerobic/aerobic bioprocess environment was made. The reactor configuration used consisted of linked anaerobic and aerobic reactors, which served as a model for a proposed bioremediation strategy. The proposed strategy was studied in two reactors before linkage. In the anaerobic compartment, the transformation of the model contaminant, 2,4,6-trichlorophenol (2,4,6-TCP), to lesser-chlorinated metabolites was shown to occur during reductive dechlorination under sulfate-reducing conditions. The consortium was also shown to desorb and mobilize 2,4,6-TCP in soils. This was followed, in the aerobic compartment, by biodegradation of the pollutant and metabolites, 2,4-dichlorophenol, 4-chlorophenol, and phenol, by immobilized white-rot fungi. The integrated process achieved elimination of the compound by more than 99% through fungal degradation of metabolites produced in the dechlorination stage. pH correction to the anaerobic reactor was found to be necessary because acidic effluent from the fungal reactor inhibited sulfate reduction and dechlorination.

  3. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  4. Evaluation of the effects of nanoscale zero-valent iron (nZVI) dispersants on intrinsic biodegradation of trichloroethylene (TCE).

    PubMed

    Chang, Y C; Huang, S C; Chen, K F

    2014-01-01

    In this study, the biodegradability of nanoscale zero-valent iron (nZVI) dispersants and their effects on the intrinsic biodegradation of trichloroethylene (TCE) were evaluated. Results of a microcosm study show that the biodegradability of three dispersants followed the sequence of: polyvinyl alcohol-co-vinyl acetate-co-itaconic acid (PV3A) > polyoxyethylene (20) sorbitan monolaurate (Tween 20) > polyacrylic acid (PAA) under aerobic conditions, and PV3A > Tween 20 > PAA under anaerobic conditions. Natural biodegradation of TCE was observed under both aerobic and anaerobic conditions. No significant effects were observed on the intrinsic biodegradation of TCE under aerobic conditions with the presence of the dispersants. The addition of PAA seemed to have a slightly adverse impact on anaerobic TCE biodegradation. Higher accumulation of the byproducts of anaerobic TCE biodegradation was detected with the addition of PV3A and Tween 20. The diversity of the microbial community was enhanced under aerobic conditions with the presence of more biodegradable PV3A and Tween 20. The results of this study indicate that it is necessary to select an appropriate dispersant for nZVI to prevent a residual of the dispersant in the subsurface. Additionally, the effects of the dispersant on TCE biodegradation and the accumulation of TCE biodegrading byproducts should also be considered.

  5. Fringe-controlled biodegradation under dynamic conditions: quasi 2-D flow-through experiments and reactive-transport modeling.

    PubMed

    Eckert, Dominik; Kürzinger, Petra; Bauer, Robert; Griebler, Christian; Cirpka, Olaf A

    2015-01-01

    Biodegradation in contaminated aquifers has been shown to be most pronounced at the fringe of contaminant plumes, where mixing of contaminated water and ambient groundwater, containing dissolved electron acceptors, stimulates microbial activity. While physical mixing of contaminant and electron acceptor by transverse dispersion has been shown to be the major bottleneck for biodegradation in steady-state plumes, so far little is known on the effect of flow and transport dynamics (caused, e.g., by a seasonally fluctuating groundwater table) on biodegradation in these systems. Towards this end we performed experiments in quasi-two-dimensional flow-through microcosms on aerobic toluene degradation by Pseudomonas putida F1. Plume dynamics were simulated by vertical alteration of the toluene plume position and experimental results were analyzed by reactive-transport modeling. We found that, even after disappearance of the toluene plume for two weeks, the majority of microorganisms stayed attached to the sediment and regained their full biodegradation potential within two days after reappearance of the toluene plume. Our results underline that besides microbial growth, also maintenance and dormancy are important processes that affect biodegradation performance under transient environmental conditions and therefore deserve increased consideration in future reactive-transport modeling.

  6. Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill.

    PubMed

    Wagland, S T; Tyrrel, S F

    2010-05-01

    This response follows on from a recent discussion by Sánchez (2009) on test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill. Test methods to assess the biodegradability/biodegradable content of organic waste are of great interest across Europe for different purposes, such as landfill acceptance criteria, monitoring treatment facility performance and for monitoring the diversion of biodegradable municipal waste (BMW) from landfill. Many studies have recently attempted to correlate short-term test methods with long-term anaerobic test methods. This response discusses recent findings and conclusions made by Sánchez (2009) and describes recent work undertaken at Cranfield University to develop the enzymatic hydrolysis test (EHT) method. The EHT has previously shown potential as a short-term, non-biological, biodegradability assessment tool, however there is a requirement to further develop this test method. We conclude that aerobic and anaerobic biological test methods are not the only suitable methods of assessing waste treatment process performance; and that alternative methods such as EHT are feasible and potentially suitable.

  7. Biodegradation of 17β-estradiol, estrone and testosterone in stream sediments

    USGS Publications Warehouse

    Bradley, Paul M.; Barber, Larry B.; Chapelle, Francis H.; Gray, James L.; Kolpin, Dana W.; McMahon, Peter B.

    2009-01-01

    Biodegradation of 17β-estradiol (E2), estrone (E1), and testosterone (T) was investigated in three wastewater treatment plant (WWTP) affected streams in the United States. Relative differences in the mineralization of [4-14C] substrates were assessed in oxic microcosms containing saturated sediment or water-only from locations upstream and downstream of the WWTP outfall in each system. Upstream sediment demonstrated significant mineralization of the “A” ring of E2, E1, and T, with biodegradation of T consistently greater than that of E2 and no systematic difference in E2 and E1 biodegradation. “A” ring mineralization also was observed in downstream sediment, with E1 and T mineralization being substantially depressed relative to upstream samples. In marked contrast, E2 mineralization in sediment immediately downstream from the WWTP outfalls was more than double that in upstream sediment. E2 mineralization was observed in water, albeit at insufficient rate to prevent substantial downstream transport. The results indicate that, in combination with sediment sorption processes which effectively scavenge hydrophobic contaminants from the water column and immobilize them in the vicinity of the WWTP outfall, aerobic biodegradation of reproductive hormones can be an environmentally important mechanism for nonconservative (destructive) attenuation of hormonal endocrine disruptors in effluent-affected streams.

  8. Biodegradation of biodiesel fuels

    SciTech Connect

    Zhang, X.; Haws, R.; Wright, B.; Reese, D.; Moeller, G.; Peterson, C.

    1995-12-31

    Biodiesel fuel test substances Rape Ethyl Ester (REE), Rape Methyl Ester (RME), Neat Rape Oil (NR), Say Methyl Ester (SME), Soy Ethyl Ester (SEE), Neat Soy Oil (NS), and proportionate combinations of RME/diesel and REE/diesel were studied to test the biodegradability of the test substances in an aerobic aquatic environment using the EPA 560/6-82-003 Shake Flask Test Method. A concurrent analysis of Phillips D-2 Reference Diesel was also performed for comparison with a conventional fuel. The highest rates of percent CO{sub 2} evolution were seen in the esterified fuels, although no significant difference was noted between them. Ranges of percent CO{sub 2} evolution for esterified fuels were from 77% to 91%. The neat rape and neat soy oils exhibited 70% to 78% CO{sub 2} evolution. These rates were all significantly higher than those of the Phillips D-2 reference fuel which evolved from 7% to 26% of the organic carbon to CO{sub 2}. The test substances were examined for BOD{sub 5} and COD values as a relative measure of biodegradability. Water Accommodated Fraction (WAF) was experimentally derived and BOD{sub 5} and COD analyses were carried out with a diluted concentration at or below the WAF. The results of analysis at WAF were then converted to pure substance values. The pure substance BOD{sub 5} and COD values for test substances were then compared to a control substance, Phillips D-2 Reference fuel. No significant difference was noted for COD values between test substances and the control fuel. (p > 0.20). The D-2 control substance was significantly lower than all test substances for BCD, values at p << 0.01. RME was also significantly lower than REE (p < 0.05) and MS (p < 0.01) for BOD{sub 5} value.

  9. Microbial community structure in a thermophilic aerobic digester used as a sludge pretreatment process for the mesophilic anaerobic digestion and the enhancement of methane production.

    PubMed

    Jang, Hyun Min; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

    2013-10-01

    An effective two-stage sewage sludge digestion process, consisting of thermophilic aerobic digestion (TAD) followed by mesophilic anaerobic digestion (MAD), was developed for efficient sludge reduction and methane production. Using TAD as a biological pretreatment, the total volatile suspended solid reduction (VSSR) and methane production rate (MPR) in the MAD reactor were significantly improved. According to denaturing gradient gel electrophoresis (DGGE) analysis, the results indicated that the dominant bacteria species such as Ureibacillus thermophiles and Bacterium thermus in TAD were major routes for enhancing soluble organic matter. TAD pretreatment using a relatively short SRT of 1 day showed highly increased soluble organic products and positively affected an increment of bacteria populations which performed interrelated microbial metabolisms with methanogenic species in the MAD; consequently, a quantitative real-time PCR indicated greatly increased Methanosarcinales (acetate-utilizing methanogens) in the MAD, resulting in enhanced methane production.

  10. Data Pre-Processing Method to Remove Interference of Gas Bubbles and Cell Clusters During Anaerobic and Aerobic Yeast Fermentations in a Stirred Tank Bioreactor

    NASA Astrophysics Data System (ADS)

    Princz, S.; Wenzel, U.; Miller, R.; Hessling, M.

    2014-11-01

    One aerobic and four anaerobic batch fermentations of the yeast Saccharomyces cerevisiae were conducted in a stirred bioreactor and monitored inline by NIR spectroscopy and a transflectance dip probe. From the acquired NIR spectra, chemometric partial least squares regression (PLSR) models for predicting biomass, glucose and ethanol were constructed. The spectra were directly measured in the fermentation broth and successfully inspected for adulteration using our novel data pre-processing method. These adulterations manifested as strong fluctuations in the shape and offset of the absorption spectra. They resulted from cells, cell clusters, or gas bubbles intercepting the optical path of the dip probe. In the proposed data pre-processing method, adulterated signals are removed by passing the time-scanned non-averaged spectra through two filter algorithms with a 5% quantile cutoff. The filtered spectra containing meaningful data are then averaged. A second step checks whether the whole time scan is analyzable. If true, the average is calculated and used to prepare the PLSR models. This new method distinctly improved the prediction results. To dissociate possible correlations between analyte concentrations, such as glucose and ethanol, the feeding analytes were alternately supplied at different concentrations (spiking) at the end of the four anaerobic fermentations. This procedure yielded low-error (anaerobic) PLSR models for predicting analyte concentrations of 0.31 g/l for biomass, 3.41 g/l for glucose, and 2.17 g/l for ethanol. The maximum concentrations were 14 g/l biomass, 167 g/l glucose, and 80 g/l ethanol. Data from the aerobic fermentation, carried out under high agitation and high aeration, were incorporated to realize combined PLSR models, which have not been previously reported to our knowledge.

  11. Phenanthrene biodegradation kinetics in unsaturated soils

    SciTech Connect

    Johnson, C.R.; Scow, K.M.

    1995-12-31

    Organic compounds when sorbed to soil solids are thought to be unavailable to soil microorganisms. The biodegradation kinetics of sorbed chemicals should thus be influenced by sorption/desorption processes as well as by the metabolic capacities of soil microbes. In the research, phenanthrene, a hydrophobic polyaromatic hydrocarbon, was used as a model compound to investigate the biodegradation kinetics of strongly sorbing organic compounds in soil. Biodegradation kinetics for phenanthrene in seven soils with moisture contents near field capacity were measured during a six and one half month experiment. Phenanthrene biodegradation rates initially increased in all soils and then declined. The declining portion of the biodegradation rate versus time plots exhibited either first order or biphasic kinetics. Both first order and biphasic kinetics are consistent with models which link microbial degradation to substrate sorption/desorption from equilibrium and kinetically controlled sorption sites. No single rate constant or analytical expression adequately captured the complexity of the observed biodegradation rates. This result is again consonant with a process derived from coupled biological and physical systems. Biodegradation kinetics were quantified using a combination of fitted and descriptive parameters. Significant correlations exist between several of the descriptive parameters. The correlations observed between descriptive biodegradation parameters mirror correlations expected from the hypothesized underlying biological process and help evince the influence this underlying process exerts on observed biodegradation kinetics.

  12. A biodegradable polymeric system for peptide–protein delivery assembled with porous microspheres and nanoparticles, using an adsorption/infiltration process

    PubMed Central

    Alcalá-Alcalá, Sergio; Urbán-Morlán, Zaida; Aguilar-Rosas, Irene; Quintanar-Guerrero, David

    2013-01-01

    A biodegradable polymeric system is proposed for formulating peptides and proteins. The systems were assembled through the adsorption of biodegradable polymeric nanoparticles onto porous, biodegradable microspheres by an adsorption/infiltration process with the use of an immersion method. The peptide drug is not involved in the manufacturing of the nanoparticles or in obtaining the microspheres; thus, contact with the organic solvent, interfaces, and shear forces required for the process are prevented during drug loading. Leuprolide acetate was used as the model peptide, and poly(d,l-lactide-co-glycolide) (PLGA) was used as the biodegradable polymer. Leuprolide was adsorbed onto different amounts of PLGA nanoparticles (25 mg/mL, 50 mg/mL, 75 mg/mL, and 100 mg/mL) in a first stage; then, these were infiltrated into porous PLGA microspheres (100 mg) by dipping the structures into a microsphere suspension. In this way, the leuprolide was adsorbed onto both surfaces (ie, nanoparticles and microspheres). Scanning electron microscopy studies revealed the formation of a nanoparticle film on the porous microsphere surface that becomes more continuous as the amount of infiltrated nanoparticles increases. The adsorption efficiency and release rate are dependent on the amount of adsorbed nanoparticles. As expected, a greater adsorption efficiency (~95%) and a slower release rate were seen (~20% of released leuprolide in 12 hours) when a larger amount of nanoparticles was adsorbed (100 mg/mL of nanoparticles). Leuprolide acetate begins to be released immediately when there are no infiltrated nanoparticles, and 90% of the peptide is released in the first 12 hours. In contrast, the systems assembled in this study released less than 44% of the loaded drug during the same period of time. The observed release profiles denoted a Fickian diffusion that fit Higuchi’s model (t1/2). The manufacturing process presented here may be useful as a potential alternative for formulating

  13. Inverse modeling of BTEX dissolution and biodegradation at the Bemidji, MN crude-oil spill site

    USGS Publications Warehouse

    Essaid, H.I.; Cozzarelli, I.M.; Eganhouse, R.P.; Herkelrath, W.N.; Bekins, B.A.; Delin, G.N.

    2003-01-01

    The U.S. Geological Survey (USGS) solute transport and biodegradation code BIOMOC was used in conjunction with the USGS universal inverse modeling code UCODE to quantify field-scale hydrocarbon dissolution and biodegradation at the USGS Toxic Substances Hydrology Program crude-oil spill research site located near Bemidji, MN. This inverse modeling effort used the extensive historical data compiled at the Bemidji site from 1986 to 1997 and incorporated a multicomponent transport and biodegradation model. Inverse modeling was successful when coupled transport and degradation processes were incorporated into the model and a single dissolution rate coefficient was used for all BTEX components. Assuming a stationary oil body, we simulated benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene (BTEX) concentrations in the oil and ground water, respectively, as well as dissolved oxygen. Dissolution from the oil phase and aerobic and anaerobic degradation processes were represented. The parameters estimated were the recharge rate, hydraulic conductivity, dissolution rate coefficient, individual first-order BTEX anaerobic degradation rates, and transverse dispersivity. Results were similar for simulations obtained using several alternative conceptual models of the hydrologic system and biodegradation processes. The dissolved BTEX concentration data were not sufficient to discriminate between these conceptual models. The calibrated simulations reproduced the general large-scale evolution of the plume, but did not reproduce the observed small-scale spatial and temporal variability in concentrations. The estimated anaerobic biodegradation rates for toluene and o-xylene were greater than the dissolution rate coefficient. However, the estimated anaerobic biodegradation rates for benzene, ethylbenzene, and m,p-xylene were less than the dissolution rate coefficient. The calibrated model was used to determine the BTEX mass balance in the oil body and groundwater plume

  14. Biodegradation of high molecular weight polylactic acid

    NASA Astrophysics Data System (ADS)

    Stloukal, Petr; Koutny, Marek; Sedlarik, Vladimir; Kucharczyk, Pavel

    2012-07-01

    Polylactid acid seems to be an appropriate replacement of conventional non-biodegradable synthetic polymer primarily due to comparable mechanical, thermal and processing properties in its high molecular weight form. Biodegradation of high molecular PLA was studied in compost for various forms differing in their specific surface area. The material proved its good biodegradability under composting conditions and all investigated forms showed to be acceptable for industrial composting. Despite expectations, no significant differences in resulting mineralizations were observed for fiber, film and powder sample forms with different specific surface areas. The clearly faster biodegradation was detected only for the thin coating on porous material with high specific surface area.

  15. Aerobic biomineralization of alpha-hexachlorocyclohexane in contaminated soil

    SciTech Connect

    Bachmann, A.; de Bruin, W.; Jumelet, J.C.; Rijnaarts, H.H.; Zehnder, A.J.

    1988-02-01

    The factors identified to be important for the aerobic biodegradation of alpha-hexachlorocyclohexane (alpha-HCH) in a soil slurry are temperature, auxiliary carbon source, substrate concentration, and soil inhomogeneities. Temperatures in the range of 20 to 30/sup 0/C were determined to be most favorable for biodegradation of alpha-HCH. No alpha-HCH biodegradation was detected at temperatures below 4/sup 0/C and above 40/sup 0/C. The addition of auxiliary organic carbon compounds showed repressive effects on alpha-HCH biomineralization. Increased oxygen partial pressures reduced the repressive effects of added auxiliary organic carbon compounds. A linear relationship between alpha-HCH concentration and its conversion rate was found in a Lineweaver-Burk plot. Inhomogeneities such as clumping of alpha-HCH significantly affected its biodegradation. Inhomogeneity as an influence on biodegradation has not drawn sufficient attention in the past, even though it certainly has affected both laboratory studies and the application of biotechnological methods to clean up contaminated sites. On the basis of metabolites detected during degradation experiments, the initial steps of aerobic alpha-HCH bioconversion in a soil slurry are proposed.

  16. Occurrence and removal of six pharmaceuticals and personal care products in a wastewater treatment plant employing anaerobic/anoxic/aerobic and UV processes in Shanghai, China.

    PubMed

    Wang, Dan; Sui, Qian; Lu, Shu-Guang; Zhao, Wen-Tao; Qiu, Zhao-Fu; Miao, Zhou-Wei; Yu, Gang

    2014-03-01

    The occurrence and removal of six pharmaceuticals and personal care products (PPCPs) including caffeine (CF), N, N-diethyl-meta-toluamide (DEET), carbamazepine, metoprolol, trimethoprim (TMP), and sulpiride in a municipal wastewater treatment plant (WWTP) in Shanghai, China were studied in January 2013; besides, grab samples of the influent were also taken every 6 h, to investigate the daily fluctuation of the wastewater influent. The results showed the concentrations of the investigated PPCPs ranged from 17 to 11,400 ng/L in the WWTP. A low variability of the PPCP concentrations in the wastewater influent throughout the day was observed, with the relative standard deviations less than 25 % for most samples. However, for TMP and CF, the slight daily fluctuation still reflected their consumption patterns. All the target compounds except CF and DEET, exhibited poor removal efficiencies (<40 %) by biological treatment process, probably due to the low temperature in the bioreactor, which was unfavorable for activated sludge. While for the two biodegradable PPCPs, CF, and DEET, the anaerobic and oxic tank made contributions to their removal while the anoxic tank had a negative effect to their elimination. The tertiary UV treatment removed the investigated PPCPs by 5-38 %, representing a crucial polishing step to compensate for the poor removal by the biologic treatment process in winter.

  17. The effectiveness of flocculants on inorganic and metallic species removal during aerobic digestion of wastewater from poultry processing plant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    : Large amount of water is used for processing of our food supplies, especially in meat processing plants. The resulting amount of wastewater cannot be discarded freely back into natural settings due to regulatory mandates, whether the sinks would be rivers, ponds, or other natural systems. These wa...

  18. The effectiveness of flocculants on inorganic and metallic species removal during aerobic digestion of wastewater from poultry processing plant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large amount of water is used for processing of our food supplies, especially in meat processing plants. The resulting amount of wastewater cannot be discarded freely back into natural settings due to regulatory mandates, whether the sinks would be rivers, ponds, or other natural systems. These wast...

  19. Biodegradation of paper waste under controlled composting conditions.

    PubMed

    Alvarez, J V López; Larrucea, M Aguilar; Bermúdez, P Arraiza; Chicote, B León

    2009-05-01

    The presence of paper in municipal solid waste (MSW) interferes with the efficiency of composting plants. The compost feedstock to these plants is between 12% and 27% paper on a dry weight basis, with an initial C:N ratio ranging from 32:1 to 57:1. Tests of the last aerobic biodegradability (LAB) of the type of paper present in paper and cardboard packaging were carried out, following UNE-EN 14046 standards. The results obtained, measured through the quantity of CO(2) generated over 45 days, compared with the maximum that could be produced (ThCO(2)), showed that the presence of paper retards, to a great degree, the biodegradation of organic material in general. Specifically, the presence of papers with a degradation D (%) >60% at 45 days (white (W) and recycled paper (R)) could be allowed, but always in proportions that did not exceed 27% in dry weight. These results can be achieved with an industrial level process, pre-treated by trituration.

  20. Aerobic microbial enhanced oil recovery

    SciTech Connect

    Torsvik, T.; Gilje, E.; Sunde, E.

    1995-12-31

    In aerobic MEOR, the ability of oil-degrading bacteria to mobilize oil is used to increase oil recovery. In this process, oxygen and mineral nutrients are injected into the oil reservoir in order to stimulate growth of aerobic oil-degrading bacteria in the reservoir. Experiments carried out in a model sandstone with stock tank oil and bacteria isolated from offshore wells showed that residual oil saturation was lowered from 27% to 3%. The process was time dependent, not pore volume dependent. During MEOR flooding, the relative permeability of water was lowered. Oxygen and active bacteria were needed for the process to take place. Maximum efficiency was reached at low oxygen concentrations, approximately 1 mg O{sub 2}/liter.

  1. The effect of recycling flux on the performance and microbial community composition of a biofilm hydrolytic-aerobic recycling process treating anthraquinone reactive dyes.

    PubMed

    Wang, Yuanpeng; Zhu, Kang; Zheng, Yanmei; Wang, Haitao; Dong, Guowen; He, Ning; Li, Qingbiao

    2011-11-25

    Synthetic dyes are extensively used and rarely degraded. Microbial decomposition is a cost-effective alternative to chemical and physical degradation processes. In this study, the decomposition of simulated anthraquinone reactive dye (Reactive Blue 19; RB19) at a concentration of 400-mg/L in wastewater by a biofilm hydrolytic-aerobic recycling system was investigated over a range of recycling fluxes. The 16S rDNA-based fingerprint technique was also used to investigate the microbial community composition. Results indicated that the recycling flux was a key factor that influenced RB19 degradation. The RB19 and COD removal efficiency could reach values as high as 82.1% and 95.4%, respectively, with a recycling flux of 10 mL/min. Molecular analysis indicated that some strains were similar to Aeromonadales, Tolumonas, and some uncultured clones were assumed to be potential decolorization bacteria. However, the microbial community composition in the reactors remained relatively stable at different recycling fluxes. This study provided insights on the decolorization capability and the population dynamics during the decolorization process of anthraquinone dye wastewater.

  2. Effects of rapid temperature rising on nitrogen removal and microbial community variation of anoxic/aerobic process for ABS resin wastewater treatment.

    PubMed

    Luo, Huilong; Song, Yudong; Zhou, Yuexi; Yang, Liwei; Zhao, Yaqian

    2017-02-01

    ABS resin wastewater is a high-temperature nitrogenous organic wastewater. It can be successfully treated with anoxic/aerobic (A/O) process. In this study, the effect of temperature on nitrogen removal and microbial community after quick temperature rise (QTR) was investigated. It was indicated that QTR from 25 to 30 °C facilitated the microbial growth and achieved a similar effluent quality as that at 25 °C. QTR from 25 to 35 °C or 40 °C resulted in higher effluent concentration of chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total nitrogen (TN), and total phosphorus (TP). Illumina MiSeq pyrosequencing analysis illustrated that the richness and diversity of the bacterial community was decreased as the temperature was increased. The percentage of many functional groups was changed significantly. QTR from 25 to 40 °C also resulted in the inhibition of ammonia oxidation rate and high concentration of free ammonia, which then inhibited the growth of NOB (Nitrospira), and thus resulted in nitrite accumulation. The high temperature above 35 °C promoted the growth of a denitrifying bacterial genus, Denitratisoma, which might increase N2O production during the denitrification process.

  3. Microbial aerobic and anaerobic degradation of acrylamide in sludge and water under environmental conditions--case study in a sand and gravel quarry.

    PubMed

    Guezennec, A G; Michel, C; Ozturk, S; Togola, A; Guzzo, J; Desroche, N

    2015-05-01

    Polyacrylamides (PAMs) are used in sand and gravel quarries as water purification flocculants for recycling process water in a recycling loop system where the flocculants remove fine particles in the form of sludge. The PAM-based flocculants, however, contain residual amounts of acrylamide (AMD) that did not react during the polymerization process. This acrylamide is released into the environment when the sludge is discharged into a settling basin. Here, we explore the microbial diversity and the potential for AMD biodegradation in water and sludge samples collected in a quarry site submitted to low AMD concentrations. The microbial diversity, analyzed by culture-dependent methods and the denaturing gradient gel electrophoresis approach, reveals the presence of Proteobacteria, Cyanobacteria, and Actinobacteria, among which some species are known to have an AMD biodegradation activity. Results also show that the two main parts of the water recycling loop-the washing process and the settling basin-display significantly different bacterial profiles. The exposure time with residual AMD could, thus, be one of the parameters that lead to a selection of specific bacterial species. AMD degradation experiments with 0.5 g L(-1) AMD showed a high potential for biodegradation in all parts of the washing process, except the make-up water. The AMD biodegradation potential in samples collected from the washing process and settling basin was also analyzed taking into account on-site conditions: low (12 °C) and high (25 °C) temperatures reflecting the winter and summer seasons, and AMD concentrations of 50 μg L(-1). Batch tests showed rapid (as little as 18 h) AMD biodegradation under aerobic and anaerobic conditions at both the winter and summer temperatures, although there was a greater lag time before activity started with the AMD biodegradation at 12 °C. This study, thus, demonstrates that bacteria present in sludge and water samples exert an in situ and rapid

  4. Bioglass 45S5 transformation and molding material in the processing of biodegradable poly-DL-lactide scaffolds for bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Abdollahi, Sara

    When bone is damaged, a scaffold can temporarily replace it in the site of injury and incite bone tissue to repair itself. A biodegradable scaffold resorbs into the body, generating non-toxic degradation products as new tissue reforms; a bioactive scaffold encourages the surrounding tissue to regenerate. In the present study, we make composite biodegradable and bioactive scaffolds using poly-DL-lactide (PDLLA), a biodegradable polymer, and incorporate Bioglass 45S5 (BG) to stimulate scaffold bioactivity. BG has an interesting trait when immersed in body fluid, a layer of hydroxycarbonate apatite, similar to the inorganic component of bone, forms on its surface. It is of utmost importance to understand the fate of BG throughout the scaffold’s processing in order to assess the scaffold’s bioactivity. In this study, the established different stages of BG reactivity have been verified by monitoring pH during BG dissolution experiments and by conducting an elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES). The composite scaffolds are synthesized by the solvent casting and particulate leaching technique and their morphology assessed by scanning electron microscopy (SEM). To understand the transformations occurred in BG during scaffold synthesis, BG as received, as well BG treated in acetone and water (the fluids involved in scaffold processing) are characterized by Fourier transform infrared (FTIR), and x-ray photoelectron spectroscopy (XPS). The results are then compared with BG extracted from scaffolds after processing. BG has been determined to start reacting during the scaffold processing. In addition, its reactivity is influenced by BG particle size. The study suggests that the presence of the polymer provides a reactive environment for BG due to pH effects. Teflon molds in scaffold fabrication are inert and biocompatibile, but their stiffness presents a challenge during de-molding. Silicone-based and polyurethane molds

  5. Biodegradable thermogels.

    PubMed

    Park, Min Hee; Joo, Min Kyung; Choi, Bo Gyu; Jeong, Byeongmoon

    2012-03-20

    All living creatures respond to external stimuli. Similarly, some polymers undergo conformational changes in response to changes in temperature, pH, magnetic field, electrical field, or the wavelength of light. In one type of stimuli-responsive polymer, thermogel polymers, the polymer aqueous solution undergoes sol-to-gel transition as the temperature increases. Drugs or cells can be mixed into the polymer aqueous solution when it is in its lower viscosity solution state. After injection of the solution into a target site, heating prompts the formation of a hydrogel depot in situ, which can then act as a drug releasing system or a cell growing matrix. In this Account, we describe key materials developed in our laboratory for the construction of biodegradable thermogels. We particularly emphasize recently developed polypeptide-based materials where the secondary structure and nanoassembly play an important role in the determining the material properties. This Account will provide insights for controlling parameters, such as the sol-gel transition temperature, gel modulus, critical gel concentration, and degradability of the polymer, when designing a new thermogel system for a specific biomedical application. By varying the stereochemistry of amino acids in polypeptides, the molecular weight of hydrophobic/hydrophilic blocks, the composition of the polypeptides, the hydrophobic end-capping of the polypeptides, and the microsequences of a block copolymer, we have controlled the thermosensitivity and nanoassembly patterns of the polymers. We have investigated a series of thermogel biodegradable polymers. Polymers such as poly(lactic acid-co-glycolic acid), polycaprolactone, poly(trimethylene carbonate), polycyanoacrylate, sebacic ester, polypeptide were used as hydrophobic blocks, and poly(ethylene glycol) and poly(vinyl pyrrolidone) were used as hydrophilic blocks. To prepare a polymer sensitive to pH and temperature, carboxylic acid or amine groups were introduced

  6. Microbial biosurfactants and biodegradation.

    PubMed

    Ward, Owen P

    2010-01-01

    Microbial biosurfactants are amphipathic molecules having typical molecular weights of 500-1500 Da, made up of peptides, saccharides or lipids or their combinations. In biodegradation processes they mediate solubilisation, mobilization and/or accession of hydrophobic substrates to microbes. They may be located on the cell surface or be secreted into the extracellular medium and they facilitate uptake of hydrophobic molecules through direct cellular contact with hydrophobic solids or droplets or through micellarisation. They are also involved in cell physiological processes such as biofilm formation and detachment, and in diverse biofilm associated processes such as wastewater treatment and microbial pathogenesis. The protection of contaminants in biosurfactants micelles may also inhibit uptake of contaminants by microbes. In bioremediation processes biosurfactants may facilitate release of contaminants from soil, but soils also tend to bind surfactants strongly which makes their role in contaminant desorption more complex. A greater understanding of the underlying roles played by biosurfactants in microbial physiology and in biodegradative processes is developing through advances in cell and molecular biology.

  7. Degradation and changes in toxicity and biodegradability of tetracycline during ozone/ultraviolet-based advanced oxidation.

    PubMed

    Luu, Huyen Trang; Lee, Kisay

    2014-01-01

    Advanced oxidation processes (AOPs) composed of O3, H2O2 and ultraviolet (UV) were applied to degrade tetracycline (TC). Degradation efficiency was evaluated in terms of changes in absorbance (ABS) and total organic carbon (TOC). The change in biotoxicity was monitored with Escherichia coli and Vibrio fischeri. The improvement in biodegradability during oxidation was demonstrated through 5-day biochemical oxygen demand/chemical oxygen demand ratio and aerobic biological treatment. The combination of O3/H2O2/UV and O3/UV showed the best performance for the reductions in ABS and TOC. However, mineralization and detoxification were not perfect under the experimental conditions that were used in this study. Therefore, for the ultimate treatment of TC compounds, it is suggested that AOP treatment is followed by biological treatment, utilizing enhanced biodegradability. In this study, aerobic biological treatment by Pseudomonas putida was performed for O3/UV-treated TC. It was confirmed that O3/UV treatment improved TOC reduction and facilitated complete mineralization in biological treatment.

  8. Biodegradation of 17β-Estradiol, Estrone and Testosterone in Stream Sediments

    NASA Astrophysics Data System (ADS)

    Bradley, P. M.; Chapelle, F. H.; Barber, L. B.; McMahon, P. B.; Gray, J. L.; Kolpin, D. W.

    2009-12-01

    The potentials for in situ biodegradation of 17β-estradiol (E2), estrone (E1), and testosterone (T) were investigated in three, hydrologically-distinct, WWTP-impacted streams in the United States. Relative differences in the mineralization of [4-14C] substrates were assessed in oxic microcosms containing sediment or water-only from locations upstream and downstream of the WWTP outfall in each system. Upstream samples provided insight into the biodegradative potential of sediment microbial communities that were not under the immediate impact of WWTP effluent. Upstream sediment from all three systems demonstrated significant mineralization of the “A” ring of E2, E1 and T, with the potential of T biodegradation consistently greater than of E2 and no systematic difference in the potentials of E2 and E1. Downstream samples provided insight into the impacts of effluent on reproductive hormone biodegradation. Significant “A” ring mineralization was also observed in downstream sediment, with the potentials for E1 and T mineralization being substantially depressed relative to upstream samples. In marked contrast, the potentials for E2 mineralization immediately downstream of the WWTP outfalls were more than double that of upstream samples. E2 mineralization was also observed in water, albeit at insufficient rate to prevent substantial downstream transport in the water column. The results of this study indicate that, in combination with sediment sorption processes which effectively scavenge hydrophobic contaminants from the water column and immobilize them in the vicinity of the WWTP outfall, aerobic biodegradation of reproductive hormones can be an environmentally important mechanism for non-conservative (destructive) attenuation of hormonal endocrine disruptors in effluent-impacted streams.

  9. Stable isotope fractionation analysis as a tool to monitor biodegradation in contaminated acquifers

    NASA Astrophysics Data System (ADS)

    Meckenstock, Rainer U.; Morasch, Barbara; Griebler, Christian; Richnow, Hans H.

    2004-12-01

    The assessment of biodegradation in contaminated aquifers has become an issue of increasing importance in the recent years. To some extent, this can be related to the acceptance of intrinsic bioremediation or monitored natural attenuation as a means to manage contaminated sites. Among the few existing methods to detect biodegradation in the subsurface, stable isotope fractionation analysis (SIFA) is one of the most promising approaches which is pronounced by the drastically increasing number of applications. This review covers the recent laboratory and field studies assessing biodegradation of contaminants via stable isotope analysis. Stable isotope enrichment factors have been found that vary from no fractionation for dioxygenase reactions converting aromatic hydrocarbons over moderate fractionation by monooxygenase reactions ( ɛ=-3‰) and some anaerobic studies on microbial degradation of aromatic hydrocarbons ( ɛ=-1.7‰) to larger fractionations by anaerobic dehalogenation reactions of chlorinated solvents ( ɛ=between -5‰ and -30‰). The different isotope enrichment factors can be related to the respective biochemical reactions. Based on that knowledge, we discuss under what circumstances SIFA can be used for a qualitative or even a quantitative assessment of biodegradation in the environment. In a steadily increasing number of cases, it was possible to explain biodegradation processes in the field based on isotope enrichment factors obtained from laboratory experiments with pure cultures and measured isotope values from the field. The review will focus on the aerobic and anaerobic degradation of aromatic hydrocarbons and chlorinated solvents as the major contaminants of groundwater. Advances in the instrumental development for stable isotope analysis are only mentioned if it is important for the understanding of the application.

  10. Biodegradation of nitroaromatic compounds.

    PubMed

    Spain, J C

    1995-01-01

    Nitroaromatic compounds are released into the biosphere almost exclusively from anthropogenic sources. Some compounds are produced by incomplete combustion of fossil fuels; others are used as synthetic intermediates, dyes, pesticides, and explosives. Recent research revealed a number of microbial systems capable of transforming or biodegrading nitroaromatic compounds. Anaerobic bacteria can reduce the nitro group via nitroso and hydroxylamino intermediates to the corresponding amines. Isolates of Desulfovibrio spp. can use nitroaromatic compounds as their source of nitrogen. They can also reduce 2,4,6-trinitrotoluene to 2,4,6-triaminotoluene. Several strains of Clostridium can catalyze a similar reduction and also seem to be able to degrade the molecule to small aliphatic acids. Anaerobic systems have been demonstrated to destroy munitions and pesticides in soil. Fungi can extensively degrade or mineralize a variety of nitroaromatic compounds. For example, Phanerochaete chrysosporium mineralizes 2,4-dinitrotoluene and 2,4,6-trinitrotoluene and shows promise as the basis for bioremediation strategies. The anaerobic bacteria and the fungi mentioned above mostly transform nitroaromatic compounds via fortuitous reactions. In contrast, a number of nitroaromatic compounds can serve as growth substrates for aerobic bacteria. Removal or productive metabolism of nitro groups can be accomplished by four different strategies. (a) Some bacteria can reduce the aromatic ring of dinitro and trinitro compounds by the addition of a hydride ion to form a hydride-Meisenheimer complex, which subsequently rearomatizes with the elimination of nitrite. (b) Monooxygenase enzymes can add a single oxygen atom and eliminate the nitro group from nitrophenols. (c) Dioxygenase enzymes can insert two hydroxyl groups into the aromatic ring and precipitate the spontaneous elimination of the nitro group from a variety of nitroaromatic compounds. (d) Reduction of the nitro group to the corresponding

  11. The combination of coagulation, acid cracking and Fenton-like processes for olive oil mill wastewater treatment: phytotoxicity reduction and biodegradability augmentation.

    PubMed

    Yazdanbakhsh, Ahmadreza; Mehdipour, Fayyaz; Eslami, Akbar; Maleksari, Hajar Sharifi; Ghanbari, Farshid

    2015-01-01

    Olive oil mill wastewater (OOMW) is one of the most important industrial wastewaters in the world due to high organic load and phenolic compounds. In this study, an integration of three processes including coagulation, acid cracking and Fenton-like was evaluated to treat OOMW. The performance of alum, ferric chloride and polyaluminum chloride was studied as coagulants. Among coagulants, ferric chloride showed the best results in comparison with the others. Coagulation process with FeCl3 removed 91.2% chemical oxygen demand (COD), 91.3% phenol, 98.9% total suspended solids and 99.2% turbidity at condition of pH = 6 and 3,000 mg/L coagulant dosage. Acid cracking process following the coagulation process with ferric chloride could slightly degrade organic compounds and provided suitable condition for the next process. Fenton-like process with zero valent iron (ZVI) was applied after coagulation and acid cracking. The optimal removal efficiency was achieved by Fenton-like process which was accomplished in condition of 7 g/L ZVI, 1,000 mg/L H2O2 and 180 min reaction time. The biodegradability of final effluent of this integration was improved significantly and biochemical oxygen demand5/COD value increased from 0.14 to 0.83. The results of germination tests revealed that phytotoxicity of the final effluent decreased.

  12. Evaluating Microtox as a tool for biodegradability assessment of partially treated solutions of pesticides using Fe3+ and TiO2 solar photo-assisted processes.

    PubMed

    Lapertot, Milena; Ebrahimi, Sirous; Oller, Isabel; Maldonado, Manuel I; Gernjak, Wolfgang; Malato, Sixto; Pulgarín, César

    2008-03-01

    To shorten phototreatment time is of major concern for the cost and energy benefits of the xenobiotics degradation performed by photocatalytic processes. Using photo-Fenton and TiO(2) phototreatments, partially photodegraded solutions of 6 separate pesticides (alachlor, atrazine, chlorfenvinphos, diuron, isoproturon and pentachlorophenol) were tested for biocompatibility, which was evaluated according to the Zahn-Wellens procedure. This study investigated if Microtox could be considered as a suitable global indicator capable of giving information on the evolution of biocompatibility of the water solution contaminated with organic pollutants during the phototreatment in order to promote biotreatment. The obtained results demonstrated that biodegradability increased significantly after short photo-Fenton treatment times for alachlor, diuron and pentachlorophenol. Uncertain results were obtained with atrazine and isoproturon. Microtox acute toxicity testing was shown to correctly represent dynamics and efficiency of phototreatment.

  13. Simultaneous C and N removal from saline salmon effluents in filter reactors comprising anoxic-anaerobic-aerobic processes: effect of recycle ratio.

    PubMed

    Giustinianovich, Elisa A; Aspé, Estrella R; Huiliñir, César E; Roeckel, Marlene D

    2014-01-01

    Salmon processing generates saline effluents with high protein load. To treat these effluents, three compact tubular filter reactors were installed and an integrated anoxic/anaerobic/aerobic process was developed with recycling flow from the reactor's exit to the inlet stream in order to save organic matter (OM) for denitrification. The reactors were aerated in the upper section with recycle ratios (RR) of 0, 2, and 10, respectively, at 30°C. A tubular reactor behave as a plug flow reactor when RR = 0, and as a mixed flow reactor when recycle increases, thus, different RR values were used to evaluate how it affects the product distribution and the global performance. Diluted salmon process effluent was prepared as substrate. Using loads of 1.0 kg COD m(-3)d(-1) and 0.15 kg total Kjeldahl nitrogen (TKN) m(-3)d(-1) at HRT of 2 d, 100% removal efficiencies for nitrite and nitrate were achieved in the anoxic-denitrifying section without effect of the dissolved oxygen in the recycled flow on denitrification. Removals >98% for total organic carbon (TOC) was achieved in the three reactors. The RR had no effect on the TOC removal; nevertheless a higher efficiency in total nitrogen removal in the reactor with the highest recycle ratio was observed: 94.3% for RR = 10 and 46.6% for RR = 2. Results showed that the proposed layout with an alternative distribution in a compact reactor can efficiently treat high organic carbon and nitrogen concentrations from a saline fish effluent with OM savings in denitrification.

  14. Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill.

    PubMed

    Wagland, S T; Tyrrel, S F; Godley, A R; Smith, R

    2009-03-01

    A wide range of waste characterization methods are available, each developed for a specific purpose such as determining compost stability, or for landfill acceptance criteria. Here test methods have been evaluated for the purpose of assessing waste treatment process performance and monitoring the diversion of biodegradable municipal waste (BMW) from landfill. The suitability factors include the timescale of the method, applicability to a wide range of materials and ability to indicate the long-term biodegradability of organic waste samples. The anaerobic test methods, whilst producing reliable results, take at least several weeks to complete, therefore, not allowing for regular routine analysis often required for diversion assessments. Short-term tests are required which can correlate with, and, therefore, estimate, values obtained from long-term anaerobic methods. Aerobic test methods were found to offer a significantly improved timescale compared with anaerobic test methods; however, they have limitations due to not measuring the full extent of sample biodegradability. No single test method was found to be completely sufficient for routine biodegradability analysis suitable for monitoring the BMW diversion from landfill. Potential areas for further research include spectrographic FT-IR or enzyme-based approaches such as the ECD or EHT methods.

  15. Microbiological and Hydrogeochemical Controls on Anaerobic Biodegradation of Petroleum Hydrocarbons: Case Study from Fort McCoy, WI

    NASA Astrophysics Data System (ADS)

    Schreiber, M. E.; Zwolinski, M. D.; Taglia, P. J.; Bahr, J. M.; Hickey, W. J.

    2001-05-01

    We are investigating the role of anaerobic processes that control field-scale BTEX loss using a variety of experimental and numerical techniques. Tracer tests, laboratory microcosms, and in situ microcosms (ISMs) were designed to examine BTEX biodegradation under intrinsic and enhanced anaerobic conditions in a BTEX plume at Fort McCoy, WI. In the tracer tests, addition of nitrate resulted in loss of toluene, ethylbenzene, and m, p-xylenes but not benzene. Laboratory microcosm and ISM experiments confirmed that nitrate addition is not likely to enhance benzene biodegradation at the site. Excess nitrate losses were observed in both field and laboratory experiments, indicating that reliance on theoretical stoichiometric equations to estimate contaminant mass losses should be re-evaluated. To examine changes in microbial community during biodegradation of BTEX under enhanced nitrate-reducing conditions, DNA was extracted from laboratory microcosm sediment, the 16S-rRNA gene was amplified using eubacterial primers, and products were separated by denaturing gradient gel electrophoresis. Banding patterns suggest that nitrate caused more of a community change than BTEX. These data suggest that nitrate plays an important role in microbial population selection. Numerical simulations were conducted to simulate the evolution of the BTEX plume and to quantify BTEX losses due to intrinsic and nitrate-enhanced biodegradation. Results suggest that the majority of intrinsic BTEX mass loss has occurred under aerobic and iron-reducing conditions. Due to depletion of solid-phase Fe(III) over time, however, future BTEX losses under iron-reducing conditions will decrease, and methanogenesis will play an increasingly important role in controlling biodegradation. The simulations also suggest that although nitrate addition will decrease TEX concentrations, source removal with intrinsic biodegradation is likely the most effective treatment method for the site.

  16. Biodegradation of subsurface oil in a tidally influenced sand beach: Impact of hydraulics and interaction with pore water chemistry

    NASA Astrophysics Data System (ADS)

    Geng, Xiaolong; Boufadel, Michel C.; Lee, Kenneth; Abrams, Stewart; Suidan, Makram

    2015-05-01

    The aerobic biodegradation of oil in tidally influenced beaches was investigated numerically in this work using realistic beach and tide conditions. A numerical model BIOMARUN, coupling a multiple-Monod kinetic model BIOB to a density-dependent variably saturated groundwater flow model 2-D MARUN, was used to simulate the biodegradation of low-solubility hydrocarbon and transport processes of associated solute species (i.e., oxygen and nitrogen) in a tidally influenced beach environment. It was found that different limiting factors affect different portions of the beach. In the upper intertidal zone, where the inland incoming nutrient concentration was large (1.2 mg N/L), oil biodegradation occurred deeper in the beach (i.e., 0.3 m below the surface). In the midintertidal zone, a reversal was noted where the biodegradation was fast at shallow locations (i.e., 0.1 m below the surface), and it was due to the decrease of oxygen with depth due to consumption, which made oxygen the limiting factor for biodegradation. Oxygen concentration in the midintertidal zone exhibited two peaks as a function of time. One peak was associated with the high tide, when dissolved oxygen laden seawater filled the beach and a second oxygen peak was observed during low tides, and it was due to pore oxygen replenishment from the atmosphere. The effect of the capillary fringe (CF) height was investigated, and it was found that there is an optimal CF for the maximum biodegradation of oil in the beach. Too large a CF (i.e., very fine material) would attenuate oxygen replenishment (either from seawater or the atmosphere), while too small a CF (i.e., very coarse material) would reduce the interaction between microorganisms and oil in the upper intertidal zone due to rapid reduction in the soil moisture at low tide. This article was corrected on 22 JUN 2015. See the end of the full text for details.

  17. Stable Carbon Isotope Ratios and Biodegradation Rates of BTEX Compounds at the Tranguch Gasoline Site, Hazelton, Pennsylvania

    DTIC Science & Technology

    2005-03-03

    Absence of Stable Carbon Isotope Fractionation of Satu- rated and Polycyclic Aromatic Hydrocarbons During Aerobic Bacterial Biodegradation ,” Org... biodegradation ; measure the overall metabolic activity and state of the on-site bacterial consortia; and determine fuel hydrocarbon stable isotope ratios...Hazleton, Pennsylvania. The goal of this study was to determine the rates and efficacy of on-site bacterial fuel hydrocarbon biodegradation ; measure

  18. Cloning and expression of vgb gene in Bacillus cereus, improve phenol and p-nitrophenol biodegradation

    NASA Astrophysics Data System (ADS)

    Vélez-Lee, Angel Eduardo; Cordova-Lozano, Felipe; Bandala, Erick R.; Sanchez-Salas, Jose Luis

    2016-02-01

    In this work, the vgb gene from Vitrocilla stercoraria was used to genetically modify a Bacillus cereus strain isolated from pulp and paper wastewater effluent. The gene was cloned in a multicopy plasmid (pUB110) or uni-copy gene using a chromosome integrative vector (pTrpBG1). B. cereus and its recombinant strains were used for phenol and p-nitrophenol biodegradation using aerobic or micro-aerobic conditions and two different temperatures (i.e. 37 and 25 °C). Complete (100%) phenol degradation was obtained for the strain where the multicopy of vgb gene was present, 98% for the strain where uni-copy gene was present and 45% for wild type strain for the same experimental conditions (i.e. 37 °C and aerobic condition). For p-nitrophenol degradation at the same conditions, the strain with the multi-copy vgb gene was capable to achieve 50% of biodegradation, ˜100% biodegradation was obtained using the uni-copy strain and ˜24% for wild type strain. When the micro-aerobic condition was tested, the biodegradation yield showed a significant decreased. The biodegradation trend observed for aerobic was similar for micro-aerobic assessments: the modified strains showed higher degradation rates when compared with wild type strain. For all experimental conditions, the highest p-nitrophenol degradation was observed using the strain with uni-copy of vgb gene. Besides the increase of biodegradative capability of the strain, insertion of the vgb gene was observed able to modify other morphological characteristics such as avoiding the typical flake formation in the B. cereus culture. In both cases, the modification seems to be related with the enhancement of oxygen supply to the cells generated by the vgb gene insertion. The application of the genetically modified microorganism (GMM) to the biodegradation of pollutants in contaminated water possesses high potential as an environmentally friendly technology to facing this emergent problem.

  19. Effect of electron beam radiation processing on mechanical and thermal properties of fully biodegradable crops straw/poly (vinyl alcohol) biocomposites

    NASA Astrophysics Data System (ADS)

    Guo, Dan

    2017-01-01

    Fully biodegradable biocomposites based on crops straw and poly(vinyl alcohol) was prepared through thermal processing, and the effect of electron beam radiation processing with N,N-methylene double acrylamide as radiation sensitizer on mechanical and thermal properties of the biocomposites were investigated. The results showed that, when the radiation dose were in the range of 0-50 kGy, the mechanical and thermal properties of the biocomposites could be improved significantly through the electron beam radiation processing, and the interface compatibility was also improved because of the formation of stable cross-linked network structure, when the radiation dose were above the optimal value (50 kGy), the comprehensive properties of the biocomposites were gradually destroyed. EB radiation processing could be used as an effective technology to improve the comprehensive performance of the biocomposites, and as a green and efficient processing technology, radiation processing takes place at room temperature, and no contamination and by-product are possible.

  20. Impact of metals on the biodegradation of organic pollutants.

    PubMed Central

    Sandrin, Todd R; Maier, Raina M

    2003-01-01

    Forty percent of hazardous waste sites in the United States are co-contaminated with organic and metal pollutants. Data from both aerobic and anaerobic systems demonstrate that biodegradation of the organic component can be reduced by metal toxicity. Metal bioavailability, determined primarily by medium composition/soil type and pH, governs the extent to which metals affect biodegradation. Failure to consider bioavailability rather than total metal likely accounts for much of the enormous variability among reports of inhibitory concentrations of metals. Metals appear to affect organic biodegradation through impacting both the physiology and ecology of organic degrading microorganisms. Recent approaches to increasing organic biodegradation in the presence of metals involve reduction of metal bioavailability and include the use of metal-resistant bacteria, treatment additives, and clay minerals. The addition of divalent cations and adjustment of pH are additional strategies currently under investigation. PMID:12826480

  1. Biodegradable synthetic bone composites

    SciTech Connect

    Liu, Gao; Zhao, Dacheng; Saiz, Eduardo; Tomsia, Antoni P.

    2013-01-01

    The invention provides for a biodegradable synthetic bone composition comprising a biodegradable hydrogel polymer scaffold comprising a plurality of hydrolytically unstable linkages, and an inorganic component; such as a biodegradable poly(hydroxyethylmethacrylate)/hydroxyapatite (pHEMA/HA) hydrogel composite possessing mineral content approximately that of human bone.

  2. Reduction of N2O and NO generation in anaerobic-aerobic (low dissolved oxygen) biological wastewater treatment process by using sludge alkaline fermentation liquid.

    PubMed

    Zhu, Xiaoyu; Chen, Yinguang

    2011-03-15

    This paper reported an efficient method to significantly reduce nitrous oxide (N(2)O) and nitric oxide (NO) generation in anaerobic-aerobic (low dissolved oxygen) processes. It was found that by the use of waste-activated sludge alkaline fermentation liquid as the synthetic wastewater-carbon source, compared with the commonly used carbon source in the literature (e.g., acetic acid), the generation of N(2)O and NO was reduced by 68.7% and 50.0%, respectively, but the removal efficiencies of total phosphorus (TP) and total nitrogen (TN) were improved. Both N(2)O and NO were produced in the low dissolved oxygen (DO) stage, and the use of sludge fermentation liquid greatly reduced their generation from the denitrification. The presences of Cu(2+) and propionic acid in fermentation liquid were observed to play an important role in the reduction of N(2)O and NO generation. The analysis of the activities of denitrifying enzymes suggested that sludge fermentation liquid caused the significant decrease of both nitrite reductase activity to NO reductase activity ratio and NO reductase activity to N(2)O reductase activity ratio, which resulted in the lower generation of NO and N(2)O. Fluorescence in situ hybridization analysis indicated that the number of glycogen accumulating bacteria, which was reported to be relevant to nitrous oxide generation, in sludge fermentation liquid reactor was much lower than that in acetic acid reactor. The quantitative detection of the nosZ gene, encoding nitrous oxide reductase, showed that the use of fermentation liquid increased the number of bacteria capable of reducing N(2)O to N(2). The feasibility of using sludge fermentation liquid to reduce NO and N(2)O generation in an anaerobic-low DO process was finally confirmed for a municipal wastewater.

  3. Biodegradable Pectin/clay Aerogels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. Addition of multivalent cations (Ca2+ and Al3+) resulted in apparent crosslinking of the polymer, and enhancement of aerogel p...

  4. Calcium precipitate induced aerobic granulation.

    PubMed

    Wan, Chunli; Lee, Duu-Jong; Yang, Xue; Wang, Yayi; Wang, Xingzu; Liu, Xiang

    2015-01-01

    Aerobic granulation is a novel biotechnology for wastewater treatment. This study refined existing aerobic granulation mechanisms as a sequencing process including formation of calcium precipitate under alkaline pH to form inorganic cores, followed by bacterial attachment and growth on these cores to form the exopolysaccharide matrix. Mature granules comprised an inner core and a matrix layer and a rim layer with enriched microbial strains. The inorganic core was a mix of different crystals of calcium and phosphates. Functional strains including Sphingomonas sp., Paracoccus sp. Sinorhizobium americanum strain and Flavobacterium sp. attached onto the cores. These functional strains promote c-di-GMP production and the expression by Psl and Alg genes for exopolysaccharide production to enhance formation of mature granules.

  5. Biodegradation of Kupferschiefer black shale organic matter (Fore-Sudetic Monocline, Poland) by indigenous microorganisms.

    PubMed

    Matlakowska, Renata; Sklodowska, Aleksandra

    2011-05-01

    This study provides the first evidence for the direct biodegradation of persistent organic matter extracted from the organic-rich polymetallic black shale ore Kupferschiefer, one of the most important sources of metals in the world. It was demonstrated that an enriched community of indigenous heterotrophic microorganisms isolated from black shale grown under aerobic conditions could utilize shale organic matter as the sole carbon and energy source. Colonization of shale organic matter was observed. The main biodegradation intermediates and products such as phosphonic acid dioctadecyl ester and isoindole-1,3 were detected in the aqueous phase of cultures. The bacterial community showed the ability to PAH biodegradation, assimilation of organic acids and esters as well as lipase activity. The intracellular accumulation of phosphorus by bacteria during growth on organic matter was confirmed. Strains within the genus Pseudomonas were found to dominate the bacterial population at the end of the experiment. The results of this study confirm that indigenous bacteria are likely to play a role in the biotransformation of black shale and can influence the geochemical cycles of ancient organic carbon in the deep terrestrial subsurface. This process may also occur in tailings ponds containing black shale, and cause the mobilization of potentially toxic compounds to the soil and groundwater.

  6. What Is Aerobic Dancing?

    MedlinePlus

    ... aerobics can reach up to six times the force of gravity, which is transmitted to each of the 26 bones in the foot. Because of the many side-to-side motions, shoes need an arch design that will compensate ...

  7. Anaerobic/aerobic treatment of selected azo dyes in wastewater

    SciTech Connect

    Seshadri, S.; Bishop, P.L. . Dept. of Civil and Environmental Engineering); Agha, A.M. . Faculty of Civil Engineering)

    1994-01-01

    Azo dyes represent the largest class of dyes in use today. Current environmental concern with these dyes revolves around the potential carcinogenic health risk presented by these dyes or their intermediate biodegradation products when exposed to microflora in the human digestive tract. These dyes may build up in the environment, since many wastewater treatment plants allow these dyes to pass through the system virtually untreated. The initial step in the degradation of these dyes is the cleavage of the Azo bond. This cleavage is often impossible under aerobic conditions, but has been readily demonstrated under anaerobic conditions. The focus of the study was to determine the feasibility of using an anaerobic fluidized-bed reactor to accomplish this cleavage. The effects of typical process variables such as hydraulic retention time (HRT), influent dye concentration levels, and degree of bed fluidization on removal efficiencies were also studied. The four dyes selected for this study were Acid-Orange 7, Acid-Orange 8, Acid-Orange 10, and Acid-Red 14. The effectiveness of using a bench-scale-activated sludge reactor as a sequenced second stage was also examined. Results indicate that nearly complete cleavage of the Azo bond is easily accomplished for each of the four dyes under hydraulic retention times of either 12 or 24 h. Initial results indicate, though, that aromatic amine by-products remain. The sequenced second stage was able to remove the remaining Chemical Oxygen Demand (COD) load to acceptable levels. Work is presently underway to determine the face of the anaerobic by-products in the aerobic second stage.

  8. Towards biodegradable wireless implants.

    PubMed

    Boutry, Clémentine M; Chandrahalim, Hengky; Streit, Patrick; Schinhammer, Michael; Hänzi, Anja C; Hierold, Christofer

    2012-05-28

    A new generation of partially or even fully biodegradable implants is emerging. The idea of using temporary devices is to avoid a second surgery to remove the implant after its period of use, thereby improving considerably the patient's comfort and safety. This paper provides a state-of-the-art overview and an experimental section that describes the key technological challenges for making biodegradable devices. The general considerations for the design and synthesis of biodegradable components are illustrated with radiofrequency-driven resistor-inductor-capacitor (RLC) resonators made of biodegradable metals (Mg, Mg alloy, Fe, Fe alloys) and biodegradable conductive polymer composites (polycaprolactone-polypyrrole, polylactide-polypyrrole). Two concepts for partially/fully biodegradable wireless implants are discussed, the ultimate goal being to obtain a fully biodegradable sensor for in vivo sensing.

  9. [Biodegradation of polyethylene].

    PubMed

    Yang, Jun; Song, Yi-ling; Qin, Xiao-yan

    2007-05-01

    Plastic material is one of the most serious solid wastes pollution. More than 40 million tons of plastics produced each year are discarded into environment. Plastics accumulated in the environment is highly resistant to biodegradation and not be able to take part in substance recycle. To increase the biodegradation efficiency of plastics by different means is the main research direction. This article reviewed the recent research works of polyethylene biodegradation that included the modification and pretreatment of polyethylene, biodegradation pathway, the relevant microbes and enzymes and the changes of physical, chemical and biological properties after biodegradation. The study directions of exploiting the kinds of life-forms of biodegradation polyethylene except the microorganisms, isolating and cloning the key enzymes and gene that could produce active groups, and enhancing the study on polyethylene biodegradation without additive were proposed.

  10. Petroleum biodegradation in marine environments.

    PubMed

    Harayama, S; Kishira, H; Kasai, Y; Shutsubo, K

    1999-08-01

    Petroleum-based products are the major source of energy for industry and daily life. Petroleum is also the raw material for many chemical products such as plastics, paints, and cosmetics. The transport of petroleum across the world is frequent, and the amounts of petroleum stocks in developed countries are enormous. Consequently, the potential for oil spills is significant, and research on the fate of petroleum in a marine environment is important to evaluate the environmental threat of oil spills, and to develop biotechnology to cope with them. Crude oil is constituted from thousands of components which are separated into saturates, aromatics, resins and asphaltenes. Upon discharge into the sea, crude oil is subjected to weathering, the process caused by the combined effects of physical, chemical and biological modification. Saturates, especially those of smaller molecular weight, are readily biodegraded in marine environments. Aromatics with one, two or three aromatic rings are also efficiently biodegraded; however, those with four or more aromatic ring are quite resistant to biodegradation. The asphaltene and resin fractions contain higher molecular weight compounds whose chemical structures have not yet been resolved. The biodegradability of these compounds is not yet known. It is known that the concentrations of available nitrogen and phosphorus in seawater limit the growth and activities of hydrocarbon-degrading microorganisms in a marine environment. In other words, the addition of nitrogen and phosphorus fertilizers to an oil-contaminated marine environment can stimulate the biodegradation of spilled oil. This notion was confirmed in the large-scale operation for bioremediation after the oil spill from the Exxon Valdez in Alaska. Many microorganisms capable of degrading petroleum components have been isolated. However, few of them seem to be important for petroleum biodegradation in natural environments. One group of bacteria belonging to the genus

  11. A laboratory batch reactor test for assessing nonspeciated volatile organic compound biodegradation in activated sludge.

    PubMed

    Cano, M L; Saterbak, A; van Compernolle, R; Williams, M P; Huot, M E; Rhodes, I A; Allen, C C

    2003-01-01

    The relative rates of biodegradation and stripping and volatilization of nonspeciated volatile organic compounds (VOCs) in wastewater treated with aerobic activated-sludge processes can be quantified using a newly developed procedure. This method was adapted from the original aerated draft tube reactor test that was developed to measure biodegradation rate constants for specific volatile pollutants of interest. The original batch test has been modified to include solid-phase microextraction (SPME) fibers for sampling in the gas phase. The experimental procedure using SPME fibers does not require specific identification and quantitation of individual pollutants and can be used to evaluate wastewater with multiple VOCs. To illustrate use of this procedure, laboratory experiments were conducted using biomass and wastewater or effluent from three activated-sludge treatment systems. Each experiment consisted of two trials: a stripping-only trial without biomass and a stripping plus biodegradation trial using biomass from the activated-sludge unit of interest. Data from the two trials were used to quantify the rates of biodegradation by difference. The activated-sludge systems tested were a laboratory diffused-air reactor treating refinery wastewater, a full-scale surface aerated reactor treating a petrochemical wastewater, and a full-scale diffused-air reactor treating a variety of industrial effluents. The biodegradation rate constant data from each laboratory batch experiment were used in model calculations to quantify the fraction emitted (fe) and the fraction biodegraded (fbio) for each system. The fe values ranged from a maximum of 0.01 to a maximum of 0.32, whereas fbio values ranged from a minimum of 0.40 to a minimum 0.95. Two of these systems had been previously tested using a more complicated experimental approach, and the current results were in good agreement with previous results. These results indicate that biodegradation rate constant data from this

  12. Comparison of Biodegradation of Nonylphenol Propoxylates with Usage of Two Different Sources of Activated Sludge.

    PubMed

    Zgoła-Grześkowiak, Agnieszka; Grześkowiak, Tomasz; Szymański, Andrzej

    2014-01-01

    Aerobic biodegradation behaviour of nonylphenol propoxylates was investigated in two tests with different sewage sludge as inocula. The samples containing target compounds were pre-concentrated using dispersive liquid-liquid microextraction and analysed with the use of high performance liquid chromatography with tandem mass spectrometry. Both primary biodegradation and formation of different biodegradation by-products were studied. Primary biodegradation of nonylphenol propoxylates was relatively slow and reached only about 70 % in over 70 days from the start of the tests. The biodegradation by-products from both oxidative and non-oxidative pathways were found. In the non-oxidative route, shortening of the propoxy chain was observed. In the oxidative pathway carboxylic acids and ketones were identified. The biodegradation by-products identified with the use of mass spectrometric detection also persisted for many days.

  13. Assessment of chloroethene biodegradation in the subsurface by microbiological, molecular and isotopic tools

    NASA Astrophysics Data System (ADS)

    Schmidt, K. R.; Kranzioch, I.; Heidinger, M.; Ertl, S.; Tiehm, A.

    2012-04-01

    A multiple lines of evidence approach to assess the biodegradation potential of contaminated sites includes - site investigation analysing pollutant distribution (compounds, concentrations, isotopic composition) and hydrochemical conditions (redox conditions) - determination of the presence of pollutant degrading bacteria in the field by microbiological (most probable number, MPN) and molecular (polymerase chain reaction, PCR) methods - analysis of degradation processes in the laboratory by microcosms with determination of site specific isotopic enrichment factors enabling the quantification of biodegradation processes in the field. Results will be shown of the application of such a multiple lines of evidence approach at a chloroethene-contaminated site in Frankenthal, Germany. In anaerobic groundwater microcosms, reductive transformation of perchloroethene (PCE) and trichloroethene (TCE) was observed to mainly proceed to cis-1,2-dichloroethene (cDCE). 16S-PCR analysis showed a wide distribution of halorespiring bacteria capable of PCE degradation to cDCE, whereas Dehalococcoides - the only organisms described so far being able of complete reductive dechlorination down to ethene - was only found in one groundwater sample. Aerobic microcosms showed metabolic degradation of the lower chlorinated compounds cDCE and vinyl chloride (VC). Co-metabolic degradation of cDCE with VC as auxiliary substrate occurred, too. Significant stable carbon isotope fractionation was observed during anaerobic degradation of PCE and TCE as well as during aerobic degradation of cDCE and VC. Compiling the results of the different assessment methods, sequential dechlorination - PCE/TCE to cDCE anaerobically and cDCE to CO2 aerobically - was demonstrated to occur at the Frankenthal site. The extent of biodegradation in the field was calculated based on the enrichment factors determined in microcosms and the 13C-isotopic composition of the contaminants on site. The application of molecular

  14. Coupling coagulation, flocculation and decantation with photo-Fenton process for treatment of industrial wastewater containing fipronil: Biodegradability and toxicity assessment.

    PubMed

    da Costa Filho, Batuira Martins; da Silva, Valdislaine Maria; Silva, Jader de Oliveira; da Hora Machado, Antonio Eduardo; Trovó, Alam Gustavo

    2016-06-01

    This work reports the treatment of wastewater containing the insecticide fipronil, integrating coagulation, flocculation and decantation in the photo-Fenton process. Under the best concentration of the coagulant - Fe(3+) (56 mg L(-1)), the suspended solids and total fipronil concentrations decreased respectively from 7000 and 20.9 mg L(-1) to 590 and 2.2 mg L(-1), but without reduction in dissolved organic carbon - DOC (1760 mg C L(-1)) and acute toxicity to Artemia salina (100%). Subsequently, the photo-Fenton process was applied as alternative of pre- or complete treatment, taking into account toxicity and biodegradability (given by biochemical oxygen demand after five days - BOD5/chemical oxygen demand - COD ratio) assessment. The best DOC and COD removal were reached with 60 and 6723 mg L(-1) of Fe(2+) and H2O2, respectively. Under these conditions, after 60 min of irradiation, 57% of DOC and 74% of COD were removed, with a decrease in acute toxicity to A. salina from 100% to 13% and an increase in the BOD5/COD ratio from 0.052 to 1.0. With these parameters, the integration of coagulation/flocculation/decantation and photo-Fenton processes may be an alternative to the pre- or complete treatment of wastewater containing fipronil.

  15. Understanding the anaerobic biodegradability of food waste: Relationship between the typological, biochemical and microbial characteristics.

    PubMed

    Fisgativa, Henry; Tremier, Anne; Le Roux, Sophie; Bureau, Chrystelle; Dabert, Patrick

    2017-03-01

    In this study, an extensive characterisation of food waste (FW) was performed with the aim of studying the relation between FW characteristics and FW treatability through an anaerobic digestion process. In addition to the typological composition (paper, meat, fruits, vegetables contents, etc) and the physicochemical characteristics, this study provides an original characterisation of microbial populations present in FW. These intrinsic populations can actively participate to aerobic and anaerobic degradation with the presence of Proteobacteria and Firmicutes species for the bacteria and of Ascomycota phylum for the fungi. However, the characterisation of FW bacterial and fungi community shows to be a challenge because of the biases generated by the non-microbial DNA coming from plant and by the presence of mushrooms in the food. In terms of relations, it was demonstrated that some FW characteristics as the density, the volatile solids and the fibres content vary as a function of the typological composition. No direct relationship was demonstrated between the typological composition and the anaerobic biodegradability. However, the Pearson's matrix results reveal that the anaerobic biodegradation potential of FW was highly related to the total chemical oxygen demand (tCOD), the total solid content (TS), the high weight organic matter molecules soluble in water (SOLW>1.5 kDa) and the C/N ratio content. These relations may help predicting FW behaviour through anaerobic digestion process. Finally, this study also showed that the storage of FW before collection, that could induce pre-biodegradation, seems to impact several biochemical characteristics and could improve the biodegradability of FW.

  16. Biodegradation of Guanidinium Ion in Aerobic Soil Samples

    DTIC Science & Technology

    1987-01-01

    Frederick. Maryland 21701 The manufacture of several munitions, polymeric resins , flame retardants, and pharmaceuticals utilizes guanidine salts as... Melamines and Guanidines. J Sci Soil Manure Jpn 15:569-574 Lees H, Quastel JH (1947) Biochemistry of Nitrification in Soil. III. Nitrification of Various

  17. Characterizing the transformation and transfer of nitrogen during the aerobic treatment of organic wastes and digestates

    SciTech Connect

    Zeng Yang; Guardia, Amaury de; Daumoin, Mylene; Benoist, Jean-Claude

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Ammonia emissions varied depending on the nature of wastes and the treatment conditions. Black-Right-Pointing-Pointer Nitrogen losses resulted from ammonia emissions and nitrification-denitrification. Black-Right-Pointing-Pointer Ammonification can be estimated from biodegradable carbon and carbon/nitrogen ratio. Black-Right-Pointing-Pointer Ammonification was the main process contributing to N losses. Black-Right-Pointing-Pointer Nitrification rate was negatively correlated to stripping rate of ammonia nitrogen. - Abstract: The transformation and transfer of nitrogen during the aerobic treatment of seven wastes were studied in ventilated air-tight 10-L reactors at 35 Degree-Sign C. Studied wastes included distinct types of organic wastes and their digestates. Ammonia emissions varied depending on the kind of waste and treatment conditions. These emissions accounted for 2-43% of the initial nitrogen. Total nitrogen losses, which resulted mainly from ammonia emissions and nitrification-denitrification, accounted for 1-76% of the initial nitrogen. Ammonification was the main process responsible for nitrogen losses. An equation which allows estimating the ammonification flow of each type of waste according to its biodegradable carbon and carbon/nitrogen ratio was proposed. As a consequence of the lower contribution of storage and leachate rates, stripping and nitrification rates of ammonia nitrogen were negatively correlated. This observation suggests the possibility of promotingnitrification in order to reduce ammonia emissions.

  18. Soil Physical Constraints on Intrinsic Biodegradation of Petroleum Vapors in a Layered Subsurface

    PubMed Central

    Kristensen, Andreas H.; Henriksen, Kaj; Mortensen, Lars; Scow, Kate M.; Moldrup, Per

    2011-01-01

    Naturally occurring biodegradation of petroleum hydrocarbons in the vadose zone depends on the physical soil environment influencing field-scale gas exchange and pore-scale microbial metabolism. In this study, we evaluated the effect of soil physical heterogeneity on biodegradation of petroleum vapors in a 16-m-deep, layered vadose zone. Soil slurry experiments (soil/water ratio 10:30 w/w, 25°C) on benzene biodegradation under aerobic and well-mixed conditions indicated that the biodegradation potential in different textured soil samples was related to soil type rather than depth, in the order: sandy loam > fine sand > limestone. Similarly, O2 consumption rates during in situ respiration tests performed at the site were higher in the sandy loam than in the fine sand, although the difference was less significant than in the slurries. Laboratory and field data generally agreed well and suggested a significant potential for aerobic biodegradation, even with nutrient-poor and deep subsurface conditions. In slurries of the sandy loam, the biodegradation potential declined with increasing in situ water saturation (i.e., decreasing air-filled porosity in the field). This showed a relation between antecedent undisturbed field conditions and the slurry biodegradation potential, and suggested airfilled porosity to be a key factor for the intrinsic biodegradation potential in the field. PMID:21617737

  19. Influence of ECAP process on mechanical and corrosion properties of pure Mg and ZK60 magnesium alloy for biodegradable stent applications.

    PubMed

    Mostaed, Ehsan; Vedani, Maurizio; Hashempour, Mazdak; Bestetti, Massimiliano

    2014-01-01

    Equal channel angular pressing (ECAP) was performed on ZK60 alloy and pure Mg in the temperature range 150-250 °C. A significant grain refinement was detected after ECAP, leading to an ultrafine grain size (UFG) and enhanced formability during extrusion process. Comparing to conventional coarse grained samples, fracture elongation of pure Mg and ZK60 alloy were significantly improved by 130% and 100%, respectively, while the tensile strength remained at high level. Extrusion was performed on ECAP processed billets to produce small tubes (with outer/inner diameter of 4/2.5 mm) as precursors for biodegradable stents. Studies on extruded tubes revealed that even after extrusion the microstructure and microhardness of the UFG ZK60 alloy were almost stable. Furthermore, pure Mg tubes showed an additional improvement in terms of grain refining and mechanical properties after extrusion. Electrochemical analyses and microstructural assessments after corrosion tests demonstrated two major influential factors in corrosion behavior of the investigated materials. The presence of Zn and Zr as alloying elements simultaneously increases the nobility by formation of a protective film and increase the local corrosion damage by amplifying the pitting development. ECAP treatment decreases the size of the second phase particles thus improving microstructure homogeneity, thereby decreasing the localized corrosion effects.

  20. Influence of ECAP process on mechanical and corrosion properties of pure Mg and ZK60 magnesium alloy for biodegradable stent applications

    PubMed Central

    Mostaed, Ehsan; Vedani, Maurizio; Hashempour, Mazdak; Bestetti, Massimiliano

    2014-01-01

    Equal channel angular pressing (ECAP) was performed on ZK60 alloy and pure Mg in the temperature range 150–250 °C. A significant grain refinement was detected after ECAP, leading to an ultrafine grain size (UFG) and enhanced formability during extrusion process. Comparing to conventional coarse grained samples, fracture elongation of pure Mg and ZK60 alloy were significantly improved by 130% and 100%, respectively, while the tensile strength remained at high level. Extrusion was performed on ECAP processed billets to produce small tubes (with outer/inner diameter of 4/2.5 mm) as precursors for biodegradable stents. Studies on extruded tubes revealed that even after extrusion the microstructure and microhardness of the UFG ZK60 alloy were almost stable. Furthermore, pure Mg tubes showed an additional improvement in terms of grain refining and mechanical properties after extrusion. Electrochemical analyses and microstructural assessments after corrosion tests demonstrated two major influential factors in corrosion behavior of the investigated materials. The presence of Zn and Zr as alloying elements simultaneously increases the nobility by formation of a protective film and increase the local corrosion damage by amplifying the pitting development. ECAP treatment decreases the size of the second phase particles thus improving microstructure homogeneity, thereby decreasing the localized corrosion effects. PMID:25482411

  1. Functional genes reveal the intrinsic PAH biodegradation potential in creosote-contaminated groundwater following in situ biostimulation.

    PubMed

    Nyyssönen, Mari; Kapanen, Anu; Piskonen, Reetta; Lukkari, Tuomas; Itävaara, Merja

    2009-08-01

    A small-scale functional gene array containing 15 functional gene probes targeting aliphatic and aromatic hydrocarbon biodegradation pathways was used to investigate the effect of a pilot-scale air sparging and nutrient infiltration treatment on hydrocarbon biodegradation in creosote-contaminated groundwater. Genes involved in the different phases of polycyclic aromatic hydrocarbon (PAH) biodegradation were detected with the functional gene array in the contaminant plume, thus indicating the presence of intrinsic biodegradation potential. However, the low aerobic fluorescein diacetate hydrolysis, the polymerase chain reaction (PCR) amplification of 16S rRNA genes closely similar to sulphate-reducing and denitrifying bacteria and the negligible decrease in contaminant concentrations showed that aerobic PAH biodegradation was limited in the anoxic groundwater. Increased abundance of PAH biodegradation genes was detected by functional gene array in the monitoring well located at the rear end of the biostimulated area, which indicated that air sparging and nutrient infiltration enhanced the intrinsic, aerobic PAH biodegradation. Furthermore, ten times higher naphthalene dioxygenase gene copy numbers were detected by real-time PCR in the biostimulated area, which was in good agreement with the functional gene array data. As a result, functional gene array analysis was demonstrated to provide a potential tool for evaluating the efficiency of the bioremediation treatment for enhancing hydrocarbon biodegradation in field-scale applications.

  2. Discerning biodegradation and adsorption of microcystin-LR in a shallow semi-enclosed bay and bacterial community shifts in response to associated process.

    PubMed

    Li, Jieming; Li, Ji; Shi, Ge; Mei, Zulin; Wang, Ruiping; Li, Dianyue

    2016-10-01

    Hepatotoxic microcystins (MCs) produced by cyanobacteria pose serious risks to aquatic ecosystems and human health, to understand elimination pathways and mechanisms for MCs, especially in a shallow and semi-enclosed eutrophic area, is of great significance. This study succeed in discerning biodegradation and adsorption of microcystin-LR (MCLR) mediated by water and/or sediment in northern part of Meiliang Bay in Lake Taihu, China, and among the first to reveal the shifts of indigenous bacterial community composition in response to MCLR-biodegradation in sediment by Illumina high-throughput sequencing (HTS). Results confirmed that biodegradation predominantly governed MCLR elimination as compared to adsorption in study area. Through faster biodegradation with a rate of 49.21μgL(-1)d(-1), lake water contributed more to overall MCLR removal than sediment. Sediment also played indispensable role in MCLR removal via primarily biodegradation by indigenous community (a rate of 17.27μgL(-1)d(-1)) and secondarily adsorption (<20% of initial concentration). HTS analysis showed that indigenous community composition shifted with decreased phylogenetic diversity in response to sediment-mediated MCLR-biodegradation. Proteobacteria became predominant (39.34-86.78%) in overall composition after biodegradation, which was mostly contributed by sharp proliferation of β-proteobacteria (22.76-74.80%), and might closely link to MCLR-biodegradation in sediment. Moreover, the members of several genera belonging to α-proteobacteria, β-proteobacteria and γ-proteobacteria seemed to be key degraders because of their dominance or increasing population as MCLR degraded. This study expands understanding on natural elimination mechanism for MCs, and provides guidance to reduce MCs' biological risks and guarantee ecosystem safety in aquatic habitats.

  3. Characterization of biodegraded coals

    SciTech Connect

    Bean, R.M.; Franz, J.A.; Campbell, J.C.; Linehan, J.C.; Stewart, D.L.; Thomas, B.L.

    1988-04-01

    We have been able to accomplish the biodegradation of bituminous Illinois No. 6 coal after a pretreatment consisting of air oxidation, using a culture of the fungus Penicillium sp. We report in this paper results of chemical and spectrometric analyses of the starting materials and products from Illinois No. 6 coal biodegradation, and compare the results with those previously reported from the biodegradation of leonardite. 13 refs., 1 fig., 5 tabs.

  4. Indoor vapor intrusion with oxygen-limited biodegradation for a subsurface gasoline source.

    PubMed

    DeVaull, George E

    2007-05-01

    Development and results are presented for a subsurface soil to indoor air chemical vapor intrusion model that includes oxygen-limited biodegradation. The algebraic model incorporates a steady-state subsurface gasoline vapor source, diffusion-dominated soil vapor transport in a homogeneous subsurface soil layer, and mixing within a building enclosure. The soil is divided into a shallow aerobic layer including biodegradation and a deeper anaerobic layer in which biodegradation is neglected. Biodegradation of multiple chemicals is included, with aerobic first-order reaction kinetics estimated from measured data. Oxygen is supplied at the soil surface below the building foundation. Oxygen demand is attributed to a sum of multiple biodegrading chemicals and to baseline respiration of native soil organic matter. The model is solved by iteratively varying the aerobic depth to match oxygen demand to oxygen supply. Model results are calculated for ranges of source concentrations, unsaturated soil characteristics, and building parameters. Results indicate vapor intrusion of petroleum hydrocarbons can be significantly less than indicated by estimates that neglect biodegradation.

  5. Metabolomics of the Bio-Degradation Process of Aflatoxin B1 by Actinomycetes at an Initial pH of 6.0

    PubMed Central

    Eshelli, Manal; Harvey, Linda; Edrada-Ebel, RuAngelie; McNeil, Brian

    2015-01-01

    Contamination of food and feed by Aflatoxin B1 (AFB1) is a cause of serious economic and health problems. Different processes have been used to degrade AFB1. In this study, biological degradation of AFB1 was carried out using three Actinomycete species, Rhodococcus erythropolis ATCC 4277, Streptomyces lividans TK 24, and S. aureofaciens ATCC 10762, in liquid cultures. Biodegradation of AFB1 was optimised under a range of temperatures from 25 to 40 °C and pH values of 4.0 to 8.0. An initial concentration of 20 µg/mL of AFB1 was used in this study. The amount of AFB1 remaining was measured against time by thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC), coupled with UV and mass spectrometry (LC-MS). All species were able to degrade the AFB1, and no significant difference was found between them. AFB1 remained in the liquid culture for R. erythropolis, S. lividans and S. aureofaciens were 0.81 µg/mL, 2.41 µg/mL and 2.78 µg/mL respectively, at the end of the first 24 h. Degradation occurred at all incubation temperatures and the pH with the optimal conditions for R. erythropolis was achieved at 30 °C and pH 6, whereas for S. lividans and S. aureofaciens the optimum conditions for degradation were 30 °C and pH 5. Analysis of the degradative route indicated that each microorganism has a different way of degrading AFB1. The metabolites produced by R. erythropolis were significantly different from the other two microorganisms. Products of degradation were identified through metabolomic studies by utilizing high-resolution mass spectral data. Mass spectrometric analysis indicated that the degradation of AFB1 was associated with the appearance of a range of lower molecular weight compounds. The pathway of degradation or chemical alteration of AFB1 was followed by means of high resolution Fourier transform mass spectrometry (HR-FTMS) analysis as well as through the MS2 fragmentation to unravel the degradative pathway for AFB1. AFB1 bio-degradation

  6. Inverse Modeling of BTEX Dissolution and Biodegradation at the Bemidji, MN Crude-Oil Spill Site

    NASA Astrophysics Data System (ADS)

    Essaid, H. I.; Cozzarelli, I. M.; Eganhouse, R. P.; Herkelrath, W. N.; Bekins, B. A.; Delin, G. N.

    2001-12-01

    The U.S. Geological Survey (USGS) solute transport and biodegradation code BIOMOC was used in conjunction with the USGS universal inverse modeling code UCODE to quantify field-scale hydrocarbon dissolution and biodegradation at the USGS Toxic Substances Hydrology Program crude-oil spill research site located near Bemidji, MN. This inverse modeling effort was novel in its use of extensive historical data compiled at the Bemidji site from 1986-1997 (1352 concentration observations from 30 wells and 66 core sections, 117 oil saturations, 235 particle-size-distributions, and 3 oil samples) and the incorporation of a multicomponent transport and biodegradation model (6 oil phase concentrations, 7 solutes and 17 reactions). The basic model assumed a stationary oil body and simulated benzene, toluene, ethylbenzene, m,p-xylene (coeluting m- and p-xylenes), o-xylene (BTEX), and isopropylbenzene mass fractions and concentrations in the oil body and ground water, respectively and dissolved. Dissolution from the oil phase and aerobic and anaerobic degradation processes were represented. The fitted parameters were the dissolution rate coefficient, first-order BTEX anaerobic degradation rates, and transverse dispersivity. Fitted parameter values were similar for simulations with uniform properties and simulations with heterogeneous hydraulic properties and seasonally variable recharge rates. The correlation coefficients for these fits were on the order of 65% and generally, the simulated concentration values were within 30% of the measured concentrations. The fitted simulations reproduced the general large-scale evolution of the plume, but did not reproduce the observed small-scale spatial and temporal variability in concentrations. The fitted field-scale dissolution rate was on the order of 10-2 per day. The fitted anaerobic biodegradation rates for toluene and o-xylene ( ~10-1 per day) were greater than the dissolution rate coefficient. However, the fitted anaerobic

  7. Development of highly porous biodegradable γ-Fe2O3/polyvinyl alcohol nanofiber mats using electrospinning process for biomedical application.

    PubMed

    Ngadiman, Nor Hasrul Akhmal; Yusof, Noordin Mohd; Idris, Ani; Misran, Effaliza; Kurniawan, Denni

    2017-01-01

    The use of electrospinning process in fabricating tissue engineering scaffolds has received great attention in recent years due to its simplicity. The nanofibers produced via electrospinning possessed morphological characteristics similar to extracellular matrix of most tissue components. Porosity plays a vital role in developing tissue engineering scaffolds because it influences the biocompatibility performance of the scaffolds. In this study, maghemite (γ-Fe2O3) was mixed with polyvinyl alcohol (PVA) and subsequently electrospun to produce nanofibers. Five factors; nanoparticles content, voltage, flow rate, spinning distance, and rotating speed were varied to produce the electrospun nanofibrous mats with high porosity value. Empirical model was developed using response surface methodology to analyze the effect of these factors to the porosity. The results revealed that the optimum porosity (90.85%) was obtained using 5% w/v nanoparticle content, 35kV of voltage, 1.1ml/h volume flow rate of solution, 8cm spinning distance and 2455rpm of rotating speed. The empirical model was verified successfully by performing confirmation experiments. The properties of optimum PVA/γ-Fe2O3 nanofiber mats such as fiber diameter, mechanical properties, and contact angle were investigated. In addition, cytocompatibility test, in vitro degradation rate, and MTT assay were also performed. Results revealed that high porosity biodegradable γ-Fe2O3/polyvinyl alcohol nanofiber mats have low mechanical properties but good degradation rates and cytocompatibility properties. Thus, they are suitable for low load bearing biomedical application or soft tissue engineering scaffold.

  8. Processes controlling the migration and biodegradation of Non-aqueous phase liquids (NAPLs) within fractured rocks in the vadose zone FY97 annual report

    SciTech Connect

    Geller, J.T.; Holman, Hoi-Ying; Conrad, M.

    1998-02-01

    Subsurface contamination from volatile organic compounds (VOCs) has been found at many Department of Energy (DOE), Department of Defense (DoD) and industrial sites due to the widespread use of organic solvents and hydrocarbon fuels. At ambient pressures and temperatures in the shallow subsurface, these substances are liquids that are immiscible with water; hence they are commonly designated as non-aqueous phase liquids (NAPLs). At some DOE sites, NAPLs are the presumed source of groundwater contamination in fractured rocks, such as basalts (at Hanford and Idaho National Engineering and Environmental Laboratory (INEEL)), shales (Oak Ridge Y-12 Plant), and welded tuffs (Los Alamos National Laboratory (LANL)). The flow, transport and biodegradation processes controlling NAPL behavior in the vadose zone must be understood in order to establish the possible extent of contamination, the risk to groundwater supplies, and appropriate remediation action. This is particularly important in and sites with deep water tables (such as at Hanford, INEEL and LANL). In fractured rock aquifers, NAPL migration is likely to be dominated by the highly permeable pathways provided by rock fractures and joints. Two- and three-phase fluid phases may be present in vadose zone fractures, including NAPL-gas, NAPL-water (in regions of perched water) and NAPL-water-gas.

  9. Dance--Aerobic and Anaerobic.

    ERIC Educational Resources Information Center

    Cohen, Arlette

    1984-01-01

    This article defines and explains aerobic exercise and its effects on the cardiovascular system. Various studies on dancers are cited indicating that dance is an anaerobic activity with some small degree of aerobic benefit. (DF)

  10. Long-term evolution of biodegradation and volatilization rates in a crude oil-contaminated aquifer

    USGS Publications Warehouse

    Chaplin, B.P.; Delin, G.N.; Baker, R.J.; Lahvis, M.A.

    2002-01-01

    Volatilization and subsequent biodegradation near the water Table make up a coupled natural attenuation pathway that results in significant mass loss of hydrocarbons. Rates of biodegradation and volatilization were documented twice 12 years apart at a crude-oil spill site near Bemidji, Minnesota. Biodegradation rates were determined by calibrating a gas transport model to O2, CO2, and CH4 gas-concentration data in the unsaturated zone. Reaction stoichiometry was assumed in converting O2 and CO2 gas-flux estimates to rates of aerobic biodegradation and CH4 gas-flux estimates to rates of methanogenesis. Model results indicate that the coupled pathway has resulted in significant hydrocarbon mass loss at the site, and it was estimated that approximately 10.52 kg/day were lost in 1985 and 1.99 kg/day in 1997. In 1985 3% of total volatile hydrocarbons diffusing from the floating oil were biodegraded in the lower 1 m of the unsaturated zone and increased to 52% by 1997. Rates of hydrocarbon biodegradation above the center of the floating oil were relatively stable from 1985 to 1997, as the primary metabolic pathway shifted from aerobic to methanogenic biodegradation. Model results indicate that in 1997 biodegradation under methanogenenic conditions represented approximately one-half of total hydrocarbon biodegradation in the lower 1 m of the unsaturated zone. Further downgradient, where substrate concentrations have greatly increased, total biodegradation rates increased by greater than an order of magnitude from 0.04 to 0.43 g/m2-day. It appears that volatilization is the primary mechanism for attenuation in early stages of plume evolution, while biodegradation dominates in later stages.

  11. Multisubstrate biodegradation kinetics of naphthalene, phenanthrene, and pyrene mixtures

    SciTech Connect

    Guha, S.; Peters, C.A.; Jaffe, P.R.

    1999-12-05

    Biodegradation kinetics of naphthalene, phenanthrene and pyrene were studied in sole-substrate systems, and in binary and ternary mixtures to examine substrate interactions. The experiments were conducted in aerobic batch aqueous systems inoculated with a mixed culture that had been isolated from soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Monod kinetic parameters and yield coefficients for the individual parameters and yield coefficients for the individual compounds were estimated from substrate depletion and CO{sub 2} evolution rate data in sole-substrate experiments. In all three binary mixture experiments, biodegradation kinetics were comparable to the sole-substrate kinetics. In the ternary mixture, biodegradation of naphthalene was inhibited and the biodegradation rates of phenanthrene and pyrene were enhanced. A multisubstrate form of the Monod kinetic model was found to adequately predict substrate interactions in the binary and ternary mixtures using only the parameters derived from sole-substrate experiments. Numerical simulations of biomass growth kinetics explain the observed range of behaviors in PAH mixtures. In general, the biodegradation rates of the more degradable and abundant compounds are reduced due to competitive inhibition, but enhanced biodegradation of the more recalcitrant PAHs occurs due to simultaneous biomass growth on multiple substrates. In PAH-contaminated environments, substrate interactions may be very large due to additive effects from the large number of compounds present.

  12. Implementation of Aerobic Programs.

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, Recreation and Dance (AAHPERD).

    This information is intended for health professionals interested in implementing aerobic exercise programs in public schools, institutions of higher learning, and business and industry workplaces. The papers are divided into three general sections. The introductory section presents a basis for adhering to a health fitness lifestyle, using…

  13. Aerobic Dance in Public Schools.

    ERIC Educational Resources Information Center

    Chiles, Barbara Ann; Moore, Suzanne

    1981-01-01

    Aerobic dance offers a challenging workout in a social atmosphere. Though some physical education instructors tend to exclude dance units from the curriculum, most could teach aerobic dance if they had a basic knowledge of aerobic routines. The outline for a unit to be used in the class is presented. (JN)

  14. Characterizing Field Biodegradation of N-nitrosodimethylamine (NDMA) in Groundwater with Active Reclaimed Water Recharge

    NASA Astrophysics Data System (ADS)

    McCraven, S.; Zhou, Q.; Garcia, J.; Gasca, M.; Johnson, T.

    2007-12-01

    N-Nitrosodimethylamine (NDMA) is an emerging contaminant in groundwater, because of its aqueous miscibility, exceptional animal toxicity, and human carcinogenicity. NDMA detections in groundwater have been tracked to either decomposition of unsymmetrical dimethylhydrazine (UDMH) used in rocket fuel facilities or chlorine disinfection in wastewater reclamation plants. Laboratory experiments on both unsaturated and saturated soil samples have demonstrated that NDMA can be biodegraded by microbial activity, under both aerobic and anaerobic conditions. However, very limited direct evidence for its biodegradation has been found from the field in saturated groundwater. Our research aimed to evaluate photolysis and biodegradation of NDMA occurring along the full travel path - from wastewater reclamation plant effluent, through rivers and spreading grounds, to groundwater. For this evaluation, we established an extensive monitoring network to characterize NDMA concentrations at effluent discharge points, surface water stations, and groundwater monitoring and production wells, during the operation of the Montebello Forebay Groundwater Recharge facilities in Los Angeles County, California. Field monitoring for NDMA has been conducted for more than six years, including 32 months of relatively lower NDMA concentrations in effluent, 43 months of elevated NDMA effluent concentrations, and 7 months with significantly reduced NDMA effluent concentrations. The NDMA effluent concentration increase and significant concentration decrease were caused by changes in treatment processes. The NDMA sampling data imply that significant biodegradation occurred in groundwater, accounting for a 90% mass reduction of NDMA over the six-year monitoring period. In addition, the occurrence of a discrete well monitored effluent release during the study period allowed critical analysis of the fate of NDMA in a well- characterized, localized groundwater flow subsystem. The data indicate that 80% of the

  15. Biodegradation of N-nitrosodimethylamine in soil from a water reclamation facility

    USGS Publications Warehouse

    Bradley, Paul M.; Carr, Steve A.; Baird, Rodger B.; Chapelle, Francis H.

    2005-01-01

    The potential introduction of N-nitrosodimethylamine (NDMA) into groundwater during water reclamation activities poses a significant risk to groundwater drinking supplies. Greater than 54% biodegradation of N-[methyl-14C]NDMA to 14CO2 or to 14CO2 and 14CH4 was observed in soil from a water reclamation facility under oxic or anoxic conditions, respectively. Likewise, biodegradation was significant in microcosms containing soil with no history of NDMA contamination. These results indicate that aerobic and anaerobic biodegradation of NDMA may be an effective component of NDMA attenuation in water reclamation facility soils.

  16. Biodegradability of new engineered fuels compared to conventional petroleum fuels and alternative fuels in current use.

    PubMed

    Speidel, H K; Lightner, R L; Ahmed, I

    2000-01-01

    Concern with environmental issues such as global climate change has stimulated research into the development of more environmentally friendly technologies and energy sources. One critical area of our economy is liquid transportation fuels. This article presents the results of the biodegradability potential of newly developed engineered fuels and compares the results to the biodegradability of conventional fuels and alternative fuels in current use. Biodegradability potential was determined under both aerobic and anaerobic conditions. Fuels that have a high degree of components derived from renewable sources proved to have a higher degradability potential than those composed of petroleum components.

  17. Biodegradation of plastics.

    PubMed

    Shimao, M

    2001-06-01

    Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. Recent work has included studies of the distribution of synthetic polymer-degrading microorganisms in the environment, the isolation of new microorganisms for biodegradation, the discovery of new degradation enzymes, and the cloning of genes for synthetic polymer-degrading enzymes.

  18. Phyllosphere yeasts rapidly break down biodegradable plastics.

    PubMed

    Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

    2011-11-29

    The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands.

  19. Sustainable multistage process for enhanced productivity of bioplastics from waste remediation through aerobic dynamic feeding strategy: Process integration for up-scaling.

    PubMed

    Amulya, K; Jukuri, Srinivas; Venkata Mohan, S

    2015-01-01

    Polyhydroxyalkanoates (PHA) production was evaluated in a multistage operation using food waste as a renewable feedstock. The first step involved the production of bio-hydrogen (bio-H2) via acidogenic fermentation. Volatile fatty acid (VFA) rich effluent from bio-H2 reactor was subsequently used for PHA production, which was carried out in two stages, Stage II (culture enrichment) and Stage III (PHA production). PHA-storing microorganisms were enriched in a sequencing batch reactor (SBR), operated at two different cycle lengths (CL-24; CL-12). Higher polymer recovery as well as VFA removal was achieved in CL-12 operation both in Stage II (16.3% dry cell weight (DCW); VFA removal, 84%) and Stage III (23.7% DCW; VFA removal, 88%). The PHA obtained was a co-polymer [P(3HB-co-3HV)] of PHB and PHV. The results obtained indicate that this integrated multistage process offers new opportunities to further leverage large scale PHA production with simultaneous waste remediation in the framework of biorefinery.

  20. Biodegradation of shrimp processing bio-waste and concomitant production of chitinase enzyme and N-acetyl-D-glucosamine by marine bacteria: production and process optimization.

    PubMed

    Suresh, P V

    2012-10-01

    A total of 250 chitinolytic bacteria from 68 different marine samples were screened employing enrichment method that utilized native chitin as the sole carbon source. After thorough screening, five bacteria were selected as potential cultures and identified as; Stenotrophomonas sp. (CFR221 M), Vibrio sp. (CFR173 M), Phyllobacteriaceae sp. (CFR16 M), Bacillus badius (CFR198 M) and Bacillus sp. (CFR188 M). All five strains produced extracellular chitinase and GlcNAc in SSF using shrimp bio-waste. Scanning electron microscopy confirmed the ability of these marine bacteria to adsorb onto solid shrimp bio-waste and to degrade chitin microfibers. HPLC analysis of the SSF extract also confirmed presence of 36-65 % GlcNAc as a product of the degradation. The concomitant production of chitinase and GlcNAc by all five strains under SSF using shrimp bio-waste as the solid substrate was optimized by 'one factor at a time' approach. Among the strains, Vibrio sp. CFR173 M produced significantly higher yields of chitinase (4.8 U/g initial dry substrate) and GlcNAc (4.7 μmol/g initial dry substrate) as compared to other cultures tested. A statistically designed experiment was applied to evaluate the interaction of variables in the biodegradation of shrimp bio-waste and concomitant production of chitinase and GlcNAc by Vibrio sp. CFR173 M. Statistical optimization resulted in a twofold increase of chitinase, and a 9.1 fold increase of GlcNAc production. These results indicated the potential of chitinolytic marine bacteria for the reclamation of shrimp bio-waste, as well as the potential for economic production of chitinase and GlcNAc employing SSF using shrimp bio-waste as an ideal substrate.

  1. COD fractions of leachate from aerobic and anaerobic pilot scale landfill reactors.

    PubMed

    Bilgili, M Sinan; Demir, Ahmet; Akkaya, Ebru; Ozkaya, Bestamin

    2008-10-01

    One of the most important problems with designing and maintaining a landfill is managing leachate that generated when water passes through the waste. In this study, leachate samples taken from aerobic and anaerobic landfill reactors operated with and without leachate recirculation are investigated in terms of biodegradable and non-biodegradable fractions of COD. The operation time is 600 days for anaerobic reactors and 250 days for aerobic reactors. Results of this study show that while the values of soluble inert COD to total COD in the leachate of aerobic landfill with leachate recirculation and aerobic dry reactors are determined around 40%, this rate was found around 30% in the leachate of anaerobic landfill with leachate recirculation and traditional landfill reactors. The reason for this difference is that the aerobic reactors generated much more microbial products. Because of this condition, it can be concluded that total inert COD/total COD ratios of the aerobic reactors were 60%, whereas those of anaerobic reactors were 50%. This study is important for modeling, design, and operation of landfill leachate treatment systems and determination of discharge limits.

  2. Biodegradability and toxicity of pharmaceuticals in biological wastewater treatment plants.

    PubMed

    Carucci, Alessandra; Cappai, Giovanna; Piredda, Martina

    2006-01-01

    In this experimental study both biological treatability of pharmaceuticals and their potential toxic effect in biological processes were evaluated. The pharmaceuticals were selected among those that are present at higher concentration in the Italian wastewater treatment plant effluents and widely used as antiulcer (ranitidine), beta-blocker (atenolol) and antibiotic (lincomycin). The present paper is the continuation of a work already presented,[1] which used a synthetic wastewater fed to laboratory scale SBR (Sequencing Batch Reactor) operated with different sludge ages (8 and 14 days), different biochemical conditions (aerobic or anoxic-aerobic mode) and several influent drug concentrations (2, 3 and 5 mg/L). In this case a real municipal wastewater was used as influent to the SBR. In parallel, batch tests were conducted to determine the removal kinetics of drugs and nitrogen. Toxicity tests using a titrimetric biosensor to verify possible inhibition on microorganisms were also performed. Finally, the possible adsorption of the pharmaceuticals on activated sludge was evaluated. The drugs under investigation showed different behaviours in terms of both biodegradability and toxicity effect on nitrifiers. Ranitidine showed generally low removal efficiencies (17-26%) and a chronic inhibition on nitrification. Atenolol showed generally higher removal efficiencies than ranitidine, even if the fairly good efficiency obtained in the previous experimentation with synthetic wastewater (up to 90%) was not attained with real wastewater (36%). No inhibition on nitrification was observed on both acclimated and non acclimated microorganisms with a high nitrification activity, whilst it was present with activated sludge characterised by a lower nitrification activity. Consistently with his pharmaceutical properties, lincomycin showed significant inhibition on nitrification activity.

  3. Biodegradation process of α-tricalcium phosphate and α-tricalcium phosphate solid solution bioceramics in vivo: a comparative study.

    PubMed

    de Aza, Piedad N; Luklinska, Zofia B; Mate-Sanchez de Val, Jose E; Calvo-Guirado, Jose L

    2013-10-01

    This article reports the structure and morphology of the in vivo interface between implants composed of either a tricalcium phosphate (αTCP) or αTCP doped with 3.0 wt% dicalcium silicate (αTCP(ss)) ceramic, and natural bone of rabbit tibias. Both interfaces developed a new bone layer in direct contact with the implants after 4 and 8 weeks of implantation. The specimens were examined using analytical scanning and transmission electron microscopy, up to the lattice plane resolution level. Degradation processes of the implants developed at the interfaces encouraged osseous tissue ingrowth into the periphery of the material, changing the microstructure of the implants. The ionic exchange initiated at the implant interface with the environment was essential in the integration process of the implant, through a dissolution–precipitation–transformation mechanism. The interfaces developed normal biological and chemical activities and remained reactive over the 8-week period. Organized collagen fibrils were found at the αTCP(ss)/bone interface after 4 weeks, whereas a collagen-free layer was present around the Si-free αTCP implants. These findings suggest that the incorporation of silicate ions into αTCP ceramic promotes processes of the bone remodeling at the bone/αTCP(ss) interface, hence the solubility rate of the aTCP(ss) material decreased.

  4. Biodegradable Grease Technology for Future Army Combat Systems

    DTIC Science & Technology

    2004-12-01

    CHNS-932 Elemental Tester [LECO, 1992]. The sewage inoculum (i.e., bacteria, yeast , fungi) was carefully prepared from the mixed liquor...rapeseed oil) which bacteria like to eat due to its natural ester flavor may substantially improve the biodegradation process of a lubricant. Also...The BLG (2) with 20% rapeseed oil provides a similar biodegradation profile to rapeseed- BLG, while the biodegradation behavior of BLG (1) with 10

  5. Biodegradation of Alpha TNT and Its Production Isomers

    DTIC Science & Technology

    1974-07-01

    1 ^*"* **».-._ BIODEGRADATION OF ALPHA TNT ANT) ITS PRODUCTION ISOMERS Annual Report-U by: Richard W. Traxler University of Rhode Island...associated with the burning process. If these nitrobodies are found to be biodegradable , they could be rendered ecologically safe by biological...molecules are biodegradable by some microbial form whereas the truly recalcitrant molecules are found in broad classes of the synthetic organic compounds

  6. The effect of temperature on the biodegradation properties of municipal solid waste.

    PubMed

    Zhao, Yan Ru; Liu, Tie Jun; Chen, Xiang Sheng; Xie, Qiang; Huang, Li Ping

    2016-03-01

    The aim of this study is to analyse the effect of temperature on the biodegradation and settlement properties of municipal solid waste by using bioreactors. Three kinds of controlled temperature were performed during the biodegradation test; the variation of weight, leachate and biogas production were carefully monitored. The degradation test indicated that more leachate leaked out owing to the external compression and polymer hydrolysis reaction in the aerobic phase, which could lead to the decrease of biodegradation rate in the anaerobic phase. A proper temperature range in favour of enhancing biodegradation of refuse was obtained, which ranged from 22 °C to 45 °C. Finally, an empirical equation of biodegradation ratio was proposed, which incorporated the temperature effect. In the end, the validation of this proposed model is verified, and is proved to be reasonable for predicting degradation velocity in landfills.

  7. Fact-finding survey of actual garbage discharged from dormitory and its biological anaerobic-aerobic treatment.

    PubMed

    Imai, T; Ukita, M; Sekine, M; Fukagawa, M; Nakanishi, H

    2000-01-01

    The objective of this study is to find a possibility of complete treatment of garbage and resource recovery (production of methane from available utility of carbon resource in garbage) by biological treatment process. As the first step, a fact-finding survey of actual garbage discharged from the dormitory of the Ube National College of Technology (equivalent to 300 population) was carried out. Second, the combined biological anaerobic-aerobic treatment, i.e. combination of upflow anaerobic sludge blanket (UASB) process and aerobic membrane bioreactor (AMB) process, was applied to the garbage treatment. The applicability and efficiency of this system were investigated in this study. The survey results showed that the composition and quantity of garbage from a student dormitory changed slightly during a week due to the change of the menu, however, they remained almost unchanged during the entire experimental period. The experimental results showed high biodegradability of the garbage, and demonstrated its suitability for methane production. The soluble nitrogen removal was high: over 97%. No excess sludge was wasted from the system. A high treatment efficiency of simultaneous organic carbon and nitrogen was obtained. The possibility of complete treatment of garbage with this process has been positively demonstrated by this study.

  8. A REVIEW OF STRUCTURE-BASED BIODEGRADATION ESTIMATION METHODS. (R825370C077)

    EPA Science Inventory

    Biodegradation, being the principal abatement process in the environment, is the most important parameter influencing the toxicity, persistence, and ultimate fate in aquatic and terrestrial ecosystems. Biodegradation of an organic chemical in natural systems may be classified ...

  9. A REVIEW OF STRUCTURE-BASED BIODEGRADATION ESTIMATION METHODS. (R825370C064)

    EPA Science Inventory

    Biodegradation, being the principal abatement process in the environment, is the most important parameter influencing the toxicity, persistence, and ultimate fate in aquatic and terrestrial ecosystems. Biodegradation of an organic chemical in natural systems may be classified ...

  10. Sulfidogenesis process to strengthen re-granulation for biodegradation of methanolic wastewater and microorganisms evolution in an UASB reactor.

    PubMed

    Lu, Xueqin; Zhen, Guangyin; Ni, Jialing; Kubota, Kengo; Li, Yu-You

    2017-01-01

    A lab-scale methanolic wastewater-fed (3000 mg COD L(-1)) UASB reactor was operated for 235 days to evaluate the influence of the sulfidogenesis process on metabolic routes, the re-granulation of dispersed granules and long-term process performance. Various sulfidogenesis scenarios were created by stepwise decreasing the influent COD/SO4(2-) ratio from 20 to 0.5 at a fixed organic loading rate (OLR) of 12 g COD L(-1) d(-1). It was shown that the conversion of methanol to methane was stable at a wide COD/SO4(2-) range of ≥2, attaining high biogas production rate of 3.78 ± 0.32 L L(-1) d(-1) with efficient concurrent removal of the total COD (96.5 ± 4.4%) and sulfate (56.3 ± 13.0%). The methane content in biogas remained relatively stable at 81.5 ± 1.6% for all COD/SO4(2-) ratios tested. The particle size of the granules was shown to clearly increase as the COD/SO4(2-) ratios decreased. A slight linear decline was noted in the number of electrons utilized by methane producing archaea (MPA) (from 98.5 ± 0.5% to 80.0 ± 2.4%), whereas consumption by sulfate reducing bacteria (SRB) increased (from 1.5 ± 0.5% to 20.0 ± 2.4%) with the decreasing COD/SO4(2-) ratio. According to the results of activity tests and microbial community analysis, the conversion of methanol to methane at a low COD/SO4(2-) ratio, except from Methanomethylovorans sp., depends not only on low levels of acetoclastic and hydrogenotrophic methanogens, but also on incomplete oxidizer SRB species (e.g. Desulfovibrio sp.) that utilize H2-CO2 with acetate to mineralize the methanol. This serves to diversify the metabolic pathway of methanol. Further analysis through scanning electron microscopy (SEM) revealed that a lower COD/SO4(2-) ratio favored the sulfidogenesis process and diversified the microbial community inside the reactor. The benefical sulfidogenesis process subsequently invoked the formation of a sufficient, rigid [-Fe-EPS-]n network (EPS: extracellular polymeric

  11. Enzyme-substrate binding landscapes in the process of nitrile biodegradation mediated by nitrile hydratase and amidase.

    PubMed

    Zhang, Yu; Zeng, Zhuotong; Zeng, Guangming; Liu, Xuanming; Chen, Ming; Liu, Lifeng; Liu, Zhifeng; Xie, Gengxin

    2013-08-01

    The continuing discharge of nitriles in various industrial processes has caused serious environmental consequences of nitrile pollution. Microorganisms possess several nitrile-degrading pathways by direct interactions of nitriles with nitrile-degrading enzymes. However, these interactions are largely unknown and difficult to experimentally determine but important for interpretation of nitrile metabolisms and design of nitrile-degrading enzymes with better nitrile-converting activity. Here, we undertook a molecular modeling study of enzyme-substrate binding modes in the bi-enzyme pathway for degradation of nitrile to acid. Docking results showed that the top substrates having favorable interactions with nitrile hydratase from Rhodococcus erythropolis AJ270 (ReNHase), nitrile hydratase from Pseudonocardia thermophila JCM 3095 (PtNHase), and amidase from Rhodococcus sp. N-771 (RhAmidase) were benzonitrile, 3-cyanopyridine, and L-methioninamide, respectively. We further analyzed the interactional profiles of these top poses with corresponding enzymes, showing that specific residues within the enzyme's binding pockets formed diverse contacts with substrates. This information on binding landscapes and interactional profiles is of great importance for the design of nitrile-degrading enzyme mutants with better oxidation activity toward nitriles or amides in the process of pollutant treatments.

  12. Microstructure, texture evolution, mechanical properties and corrosion behavior of ECAP processed ZK60 magnesium alloy for biodegradable applications.

    PubMed

    Mostaed, Ehsan; Hashempour, Mazdak; Fabrizi, Alberto; Dellasega, David; Bestetti, Massimiliano; Bonollo, Franco; Vedani, Maurizio

    2014-09-01

    Ultra-fine grained ZK60 Mg alloy was obtained by multi-pass equal-channel angular pressing at different temperatures of 250°C, 200°C and 150°C. Microstructural observations showed a significant grain refinement after ECAP, leading to an equiaxed and ultrafine grain (UFG) structure with average size of 600nm. The original extrusion fiber texture with planes oriented parallel to extrusion direction was gradually undermined during ECAP process and eventually it was substituted by a newly stronger texture component with considerably higher intensity, coinciding with ECAP shear plane. A combination of texture modification and grain refinement in UFG samples led to a marked reduction in mechanical asymmetric behavior compared to the as-received alloy, as well as adequate mechanical properties with about 100% improvement in elongation to failure while keeping relatively high tensile strength. Open circuit potential, potentiodynamic and weight loss measurements in a phosphate buffer solution electrolyte revealed an improved corrosion resistance of UFG alloy compared to the extruded one, stemming from a shift of corrosion regime from localized pitting in the as-received sample to a more uniform corrosion mode with reduced localized attack in ECAP processed alloy. Compression tests on immersed samples showed that the rate of loss of mechanical integrity in the UFG sample was lower than that in the as-received sample.

  13. Hazard identification of pharmaceutical wastewaters using biodegradability studies.

    PubMed

    Zgajnar Gotvajn, A; Zagorc-Koncan, J

    2003-01-01

    A reliable wastewater characterization is an integral part of treatment and management strategies for industrial effluents. This is especially true for the pharmaceutical industry, which exhibits significant differences in its line of activity, generating effluents of very specific and complex natures. Any hazard or risk assessment of wastewater and/or determination of its treatability must include an evaluation of its degradability. Usually various non-standardized laboratory or pilot-scale long-term tests are run by measuring summary parameters for several days to determine the biodegradation potential of the effluent. A complex approach, based on stabilization studies, was proposed to determine the hazardous impact of wastewaters in terms of biodegradable and persistent toxicity. The objective of our work was to carry out complex hazard evaluation of pharmaceutical wastewaters. Whole effluent toxicity was determined using two different toxicity tests. First, we measured the inhibition of oxygen consumption by activated sludge. The test indicated toxicity of the wastewater and thus we performed an additional acute toxicity test with luminescent bacteria Vibrio fisheri. The next step was the determination of whole effluent ready biodegradability. It was determined with simultaneous measurement of oxygen consumption (ISO 9804) and carbon dioxide production (ISO 9439) in a closed respirometer, accompanied by DOC/IC measurements. The pharmaceutical wastewater degraded readily (83%, lag phase was 2 days, biodegradation rate was 0.33999 day(-1)) on the basis of O2 measurements. The biodegradation, calculated from the CO2 measurements, was comparable. We also applied mass balances of DOC/IC at the beginning and at the end of biodegradation experiments to confirm the extent and rate of biodegradation. The determination of hazardous impact and treatability of the effluent was concluded with aerobic stabilization studies. Biodegradation of the wastewater during the study

  14. Biodegradable kinetics of plastics under controlled composting conditions.

    PubMed

    Leejarkpai, Thanawadee; Suwanmanee, Unchalee; Rudeekit, Yosita; Mungcharoen, Thumrongrut

    2011-06-01

    This study models and evaluates the kinetics of C-CO(2) evolution during biodegradation of plastic materials including Polyethylene (PE), PE/starch blend (PE/starch), microcrystalline cellulose (MCE), and Polylactic acid (PLA). The aerobic biodegradation under controlled composting conditions was monitorated according to ISO 14855-1, 2004. The kinetics model was based on first order reaction in series with a flat lag phase. A non-linear regression technique was used to analyze the experimental data. SEM studies of the morphology of the samples before and after biodegradation testing were used to confirm the biodegradability of plastics and the accuracy of the model. The work showed that MCE and PLA produced the high amounts of C-CO(2) evolution, which gave readily hydrolysable carbon values of 55.49% and 40.17%, respectively with readily hydrolysis rates of 0.338 day(-1) and 0.025 day(-1), respectively. Whereas, a lower amount of C-CO(2) evolution was found in PE/starch, which had a high concentration of moderately hydrolysable carbon of 97.74% and a moderate hydrolysis rate of 0.00098 day(-1). The mineralization rate of PLA was 0.500 day(-1) as a lag phase was observed at the beginning of the biodegradability test. No lag phase was observed in the biodegradability testing of the PE/starch and MCE. The mineralization rates of the PE/starch and MCE were found to be 1.000 day(-1), and 1.234 day(-1), respectively. No C-CO(2) evolution was observed during biodegradability testing of PE, which was used for reference as a non-biodegradable plastics sample.

  15. Recent advances in biodegradable nanocomposites.

    PubMed

    Pandey, Jitendra K; Kumar, A Pratheep; Misra, Manjusri; Mohanty, Amar K; Drzal, Lawrence T; Singh, Raj Pal

    2005-04-01

    There is growing interest in developing bio-based products and innovative process technologies that can reduce the dependence on fossil fuel and move to a sustainable materials basis. Biodegradable bio-based nanocomposites are the next generation of materials for the future. Renewable resource-based biodegradable polymers including cellulosic plastic (plastic made from wood), corn-derived plastics, and polyhydroxyalkanoates (plastics made from bacterial sources) are some of the potential biopolymers which, in combination with nanoclay reinforcement, can produce nanocomposites for a variety of applications. Nanocomposites of this category are expected to possess improved strength and stiffness with little sacrifice of toughness, reduced gas/water vapor permeability, a lower coefficient of thermal expansion, and an increased heat deflection temperature, opening an opportunity for the use of new, high performance, lightweight green nanocomposite materials to replace conventional petroleum-based composites. The present review addresses this green material, including its technical difficulties and their solutions.

  16. Effect of intermediate compounds and products on wet oxidation and biodegradation rates of pharmaceutical compounds.

    PubMed

    Collado, Sergio; Laca, Adriana; Diaz, Mario

    2013-06-01

    Kinetics of pure compounds in batch agitated reactors are useful data to clarify the characteristics of a given reaction, but they frequently do not provide the required information to design industrial mixed continuous processes because in this case the final and intermediate products interact with the reaction of interest, due to backmixing effects. Simultaneously, the presence and transformations of other compounds, frequent in industrial wastewater treatments, adds more complexity to these types of interactions, whose effect can be different, favorable or unfavorable, for chemical or biological reactions. In this work, batch laboratory reactor data were obtained for the wet oxidation and biodegradation of four phenolic compounds present in a pharmaceutical wastewater and then compared with those collected from industrial continuous stirred tank reactors. For wet oxidation, batch laboratory degradation rates were significantly lower than those found in industrial continuous stirred operation. This behavior was explained by a different distribution of intermediate compounds in lab and industrial treatments, caused by the degree of backmixing and the synergistic effects between phenolic compounds (matrix effects). On the other hand, the specific utilization rates during aerobic biodegradation in the continuous industrial operation were lower than those measured in the laboratory, due to the simultaneous presence of the four pollutants in the industrial process (matrix effects) increasing the inhibitory effects of these compounds and its intermediates.

  17. Biodegradation of low-density polyethylene (LDPE) by isolated fungi in solid waste medium

    SciTech Connect

    Zahra, Sahebnazar; Abbas, Shojaosadati Seyed; Mahsa, Mohammad-Taheri; Mohsen, Nosrati

    2010-03-15

    In this study, biodegradation of low-density polyethylene (LDPE) by isolated landfill-source fungi was evaluated in a controlled solid waste medium. The fungi, including Aspergillus fumigatus, Aspergillus terreus and Fusarium solani, were isolated from samples taken from an aerobic aged municipal landfill in Tehran. These fungi could degrade LDPE via the formation of a biofilm in a submerged medium. In the sterilized solid waste medium, LPDE films were buried for 100 days in a 1-L flask containing 400 g sterile solid waste raw materials at 28 deg. C. Each fungus was added to a separate flask. The moisture content and pH of the media were maintained at the optimal levels for each fungus. Photo-oxidation (25 days under UV-irradiation) was used as a pretreatment of the LDPE samples. The progress of the process was monitored by measurement of total organic carbon (TOC), pH, temperature and moisture. The results obtained from monitoring the process using isolated fungi under sterile conditions indicate that these fungi are able to grow in solid waste medium. The results of FT-IR and SEM analyses show that A. terreus and A. fumigatus, despite the availability of other organic carbon of materials, could utilize LDPE as carbon source. While there has been much research in the field of LDPE biodegradation under solid conditions, this is the first report of degradation of LDPE by A. fumigatus.

  18. Application of electrolysis to stimulate microbial reductive PCE dechlorination and oxidative VC biodegradation.

    PubMed

    Lohner, Svenja T; Tiehm, Andreas

    2009-09-15

    A novel approach was applied to stimulate biodegradation of chloroethenes bya coupled bioelectro-process. In a flow-through column system, microbial dechlorination of tetrachloroethene to cis-dichloroethene, vinyl chloride, and ethene was stimulated by hydrogen produced by water electrolysis. Dechlorinating bacteria (Dehalococcoides spp. and Desulfitobacterium spp.) and also methanogens and homoacetogens were detected in the anaerobic column. Simultaneously, oxidative biodegradation of lower chlorinated metabolites (vinyl chloride) was stimulated by electrolytic oxygen formation in the corresponding aerobic column. The process was stable for more than 100 days and an average removal of approximately 23 micromol/d PCE and 72 micromo/d vinyl chloride was obtained with a current density of 0.05 mA/cm2. Abiotic electrochemical degradation of the contaminants was not observed. Microbial dechlorination correlated with the current densities in the applied range of 0.01-0.05 mA/cm2. The results are promising for environmental applications, since with electrolysis hydrogen and oxygen can be supplied continuously to chloroethene degrading microorganisms, and the supply rates can be easily controlled by adjusting the electric current.

  19. Impact of epiphytic and endogenous enzyme activities of senescent maize leaves and roots on the soil biodegradation process.

    PubMed

    Zafar Amin, Bilal Ahmad; Beaugrand, Johnny; Debeire, Philippe; Chabbert, Brigitte; Bertrand, Isabelle

    2011-11-01

    This study was focused on investigating the role of the initial residue community, i.e. microorganisms and enzymes from the epiphytic and endophytic compartments, in soil decomposition processes. Aerial and underground parts (leaves and roots) of maize (Zea mays L.) plants were γ-irradiated, surface-sterilized with sodium hypochlorite (NaOCl)/ethanol or non-sterilized (controls), while the outer surface morphology of maize leaves and roots was examined by scanning electron microscopy (SEM). Non-sterilized and sterilized maize leaves and roots were incubated in soil to study carbon (C) mineralization kinetics and enzyme dynamics (L-leucine aminopeptidase, CBH-1, xylanase, cellulase and laccase). SEM results showed that initial microbial colonization was more pronounced on non-sterilized leaf and root surfaces than on sterilized samples. The hypochlorite treatment removed a part of the soluble components of leaves by washing and no specific effect of any type of colonizing microorganisms was observed on C mineralization. In contrast, γ irradiation and hypochlorite treatments did not affect root chemical characteristics and the quantitative effect of initial residue-colonizing microorganisms on C mineralization was demonstrated. The variations in C mineralization and enzyme dynamics between non-sterilized and sterilized roots suggested that activities of epiphytic and endogenic microorganisms were of the same order of magnitude.

  20. MTBE BIODEGRADATION IN A GRAVITY FLOW, HIGH-BIOMASS RETAINING BIOREACTOR

    EPA Science Inventory

    The aerobic biodegradation of methyl tert-butyl ether (MtBE), a widely used fuel oxygenate, was investigated using a pilot-scale biomass-retaining bioreactor called a Biomass Concentrator Reactor (BCR). The reactor was operated for a year at a flow rate of 2500 L/d on Ci...

  1. Biofuel components change the ecology of bacterial volatile petroleum hydrocarbon degradation in aerobic sandy soil.

    PubMed

    Elazhari-Ali, Abdulmagid; Singh, Arvind K; Davenport, Russell J; Head, Ian M; Werner, David

    2013-02-01

    We tested the hypothesis that the biodegradation of volatile petroleum hydrocarbons (VPHs) in aerobic sandy soil is affected by the blending with 10 percent ethanol (E10) or 20 percent biodiesel (B20). When inorganic nutrients were scarce, competition between biofuel and VPH degraders temporarily slowed monoaromatic hydrocarbon degradation. Ethanol had a bigger impact than biodiesel, reflecting the relative ease of ethanol compared to methyl ester biodegradation. Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes revealed that each fuel mixture selected for a distinct bacterial community, each dominated by Pseudomonas spp. Despite lasting impacts on soil bacterial ecology, the overall effects on VHP biodegradation were minor, and average biomass yields were comparable between fuel types, ranging from 0.40 ± 0.16 to 0.51 ± 0.22 g of biomass carbon per gram of fuel carbon degraded. Inorganic nutrient availability had a greater impact on petroleum hydrocarbon biodegradation than fuel composition.

  2. Surface integrity and process mechanics of laser shock peening of novel biodegradable magnesium-calcium (Mg-Ca) alloy.

    PubMed

    Sealy, M P; Guo, Y B

    2010-10-01

    Current permanent metallic biomaterials of orthopedic implants, such as titanium, stainless steel, and cobalt-chromium alloys, have excellent corrosive properties and superior strengths. However, their strengths are often too high resulting in a stress shielding effect that is detrimental to the bone healing process. Without proper healing, costly and painful revision surgeries may be required. The close Young's modulus between magnesium-based implants and cancellous bones has the potential to minimize stress shielding while providing both biocompatibility and adequate mechanical properties. The problem with Mg implants is how to control corrosion rates so that the degradation of Mg implants matches that of bone growth. Laser shock peening (LSP) is an innovative surface treatment method to impart compressive residual stress to a novel Mg-Ca implant. The high compressive residual stress has great potential to slow corrosion rates. Therefore, LSP was initiated in this study to investigate surface topography and integrity produced by sequential peening a Mg-Ca alloy. Also, a 3D semi-infinite simulation was developed to predict the topography and residual stress fields produced by sequential peening. The dynamic mechanical behavior of the biomaterial was modeled using a user material subroutine from the internal state variable plasticity model. The temporal and spatial peening pressure was modeled using a user load subroutine. The simulated dent agrees with the measured dent topography in terms of profile and depth. Sequential peening was found to increase the tensile pile-up region which is critical to orthopedic applications. The predicted residual stress profiles are also presented.

  3. Functionalized synthetic biodegradable polymer scaffolds for tissue engineering.

    PubMed

    Liu, Xiaohua; Holzwarth, Jeremy M; Ma, Peter X

    2012-07-01

    Scaffolds (artificial ECMs) play a pivotal role in the process of regenerating tissues in 3D. Biodegradable synthetic polymers are the most widely used scaffolding materials. However, synthetic polymers usually lack the biological cues found in the natural extracellular matrix. Significant efforts have been made to synthesize biodegradable polymers with functional groups that are used to couple bioactive agents. Presenting bioactive agents on scaffolding surfaces is the most efficient way to elicit desired cell/material interactions. This paper reviews recent advancements in the development of functionalized biodegradable polymer scaffolds for tissue engineering, emphasizing the syntheses of functional biodegradable polymers, and surface modification of polymeric scaffolds.

  4. Aerobic biotransformation and mineralization of 2,4,6-trinitrotoluene

    SciTech Connect

    Bae, B.H.; Autenrieth, R.L.; Bonner, J.S.

    1995-12-31

    Respirometric mineralization studies of 2,4,6-trinitrotoluene (TNT) were conducted with microorganisms isolated from a site contaminated with munitions waste in Illinois. Nine aerobic bacterial species were isolated under a carbon- and nitrogen-limited condition and tentatively identified as: one Pseudomonas species; one Enterobacter species; and seven Alcaligenes species. Experiments were performed using each of the nine organisms individually and with a consortium of all nine bacterial species. The aerobic microorganisms were cultured in a sterile nutrient solution with glucose and 20 mg/L TNT. Mineralization was determined using uniformly ring-labeled {sup 14}C-TNT in a respirometer that trapped the evolved CO{sub 2}. Biodegradation behavior was characterized based on oxygen consumption, distribution of {sup 14}C activity, and high-performance liquid chromatography (HPLC) analysis of TNT and its transformation products.

  5. Biodegradation of nicotine by a newly isolated Pseudomonas stutzeri JZD

    NASA Astrophysics Data System (ADS)

    Petricevic, Jelena; Gujanicic, Vera; Radic, Danka; Jovicic Petrovic, Jelena; Jovic, Jelena; Raicevic, Vera

    2013-04-01

    The tobacco-manufacturing process and all activities that use tobacco, produce solid or liquid wastes with high concentrations of nicotine. Nicotine is a significant toxic waste product in tobacco industry. This waste is classified as 'toxic and hazardous' by European Union regulations when the nicotine content exceeds 500 milligrams per kilogram dry weight. Therefore, there is a major environmental requirement to remove nicotine from tobacco wastes. Bioremediation techniques which involve nicotine degradation by microorganisms have attracted attention during the last years, because microorganisms have the potential to reduce nicotine levels in tobacco and to detoxify tobacco wastes. The aim of this study is isolation and identification of nicotine degraded bacteria and optimization of nicotine degradation in laboratory conditions. An aerobic bacterial strain capable of effectively degrading nicotine was isolated from the tobacco industry waste, Serbia. After isolation, the liquid culture was spread onto the solid plates of the nicotine inorganic salt medium using the dilution plate method. Cell morphology of strain was observed by a light microscope and physiological characteristics were determined by Api technique and sequence analyzes of 16S rDNA. This isolate was identified as Pseudomonas stutzeri based on morphology, physiological characteristics, and Apiweb technique. Comparison with sequences available in data library showed the 99% similarity with 16S rDNA gene sequence of the species Pseudomonas stutzeri ( GenBank Acc. No. CP003725). We analyzed the effect of initial nicotine concentration (1g/L, 1.5 g/L, 2.5 g/L) on microbial activity in aim to optimize biodegradation. The effect of cultivation temperature (25°C; 30°C; 37°C) on nicotine degradation by P. stutzeri was evaluated after 24 h of cultivation, with 1.5 g/L nicotine added as the sole carbon source. Effect of biodegradation has depended on initial concentration. During incubation, number of

  6. Characterization of biodegraded coals

    SciTech Connect

    Bean, R.M.; Franz, J.A.; Campbell, J.A.; Linehan, J.C.; Stewart, D.L.; Thomas, B.L.

    1988-01-01

    Microbial degradation of coals to materials that are soluble in water has been a topic of intensive research for the last few years. The potential for economical recovery of low-grade coals, coupled with possibilities for further upgrading by microbial desulfurization or methanation has spurred intensive research at a number of laboratories. Until very recently, coal biodegradation has been accomplished using low-grade, naturally oxidized coals such as leonardiate, or coals subjected to pretreatment with oxidizing chemicals. The authors have been able to accomplish the biodegradation of bituminous Illinois 6 coal after a pretreatment consisting of air oxidation, using a culture of the fungus Penicillium sp. They report in this paper results of chemical and spectrometric analyses of the starting materials and products from Illinois 6 coal biodegradation, and compare the results with those previously reported from the biodegradation of leonardite.

  7. Microbial colonization and degradation of polyethylene and biodegradable plastic bags in temperate fine-grained organic-rich marine sediments.

    PubMed

    Nauendorf, Alice; Krause, Stefan; Bigalke, Nikolaus K; Gorb, Elena V; Gorb, Stanislav N; Haeckel, Matthias; Wahl, Martin; Treude, Tina

    2016-02-15

    To date, the longevity of plastic litter at the sea floor is poorly constrained. The present study compares colonization and biodegradation of plastic bags by aerobic and anaerobic benthic microbes in temperate fine-grained organic-rich marine sediments. Samples of polyethylene and biodegradable plastic carrier bags were incubated in natural oxic and anoxic sediments from Eckernförde Bay (Western Baltic Sea) for 98 days. Analyses included (1) microbial colonization rates on the bags, (2) examination of the surface structure, wettability, and chemistry, and (3) mass loss of the samples during incubation. On average, biodegradable plastic bags were colonized five times higher by aerobic and eight times higher by anaerobic microbes than polyethylene bags. Both types of bags showed no sign of biodegradation during this study. Therefore, marine sediment in temperate coastal zones may represent a long-term sink for plastic litter and also supposedly compostable material.

  8. Three-dimensional model for subsurface transport and biodegradation

    SciTech Connect

    Waddill, D.W.; Widdowson, M.A.

    1998-04-01

    This paper describes and demonstrates a numerical model for subsurface solute transport with aerobic and sequential anaerobic biodegradation. The model can depict multiple constituents in a three-dimensional (3D), anisotropic, heterogeneous domain. Hydrocarbon contaminants are simulated as electron donors for microbial growth, and available electron acceptors (EAs) may be utilized simultaneously or in the following sequence: O{sub 2}, NO{sub 3}{sup {minus}}, Mn(IV), Fe(III), SO{sub 4}{sup 2{minus}}, and CO{sub 2}. The model can account for Mn(II), Fe(II), H{sub w}S, CH{sub 4}, and a user-defined nitrogenous compound as products of biodegradation. Biodegradation of each hydrocarbon substrate follows Monod kinetics, modified to include the effects of EA and nutrient availability. Inhibition functions allow any EA to inhibit the utilization of all other EAs that provide less energy to the microbes. Microbial biomass is conceptualized as scattered microcolonies attached to the porous medium. The model assumes that interphase diffusion limitations to microbial growth are negligible and no geometrical parameters are assigned to the colonies. The behavior of the model was demonstrated using simple, hypothetical test cases. Transport of a biodegradable hydrocarbon was compared to a nonbiodegradable tracer in a 3D, hypothetical domain. Anaerobic biodecay significantly reduced predicted contaminant concentrations and travel distance. Biodegradation of the total contaminant mass depends on EA availability and did not follow first-order kinetics.

  9. Aerobic and two-stage anaerobic-aerobic sludge digestion with pure oxygen and air aeration.

    PubMed

    Zupancic, Gregor D; Ros, Milenko

    2008-01-01

    The degradability of excess activated sludge from a wastewater treatment plant was studied. The objective was establishing the degree of degradation using either air or pure oxygen at different temperatures. Sludge treated with pure oxygen was degraded at temperatures from 22 degrees C to 50 degrees C while samples treated with air were degraded between 32 degrees C and 65 degrees C. Using air, sludge is efficiently degraded at 37 degrees C and at 50-55 degrees C. With oxygen, sludge was most effectively degraded at 38 degrees C or at 25-30 degrees C. Two-stage anaerobic-aerobic processes were studied. The first anaerobic stage was always operated for 5 days HRT, and the second stage involved aeration with pure oxygen and an HRT between 5 and 10 days. Under these conditions, there is 53.5% VSS removal and 55.4% COD degradation at 15 days HRT - 5 days anaerobic, 10 days aerobic. Sludge digested with pure oxygen at 25 degrees C in a batch reactor converted 48% of sludge total Kjeldahl nitrogen to nitrate. Addition of an aerobic stage with pure oxygen aeration to the anaerobic digestion enhances ammonium nitrogen removal. In a two-stage anaerobic-aerobic sludge digestion process within 8 days HRT of the aerobic stage, the removal of ammonium nitrogen was 85%.

  10. Nitrification and aerobic denitrification in anoxic-aerobic sequencing batch reactor.

    PubMed

    Alzate Marin, Juan C; Caravelli, Alejandro H; Zaritzky, Noemí E

    2016-01-01

    The aim of this study was to evaluate the feasibility of achieving nitrogen (N) removal using a lab-scale sequencing batch reactor (SBR) exposed to anoxic/aerobic (AN/OX) phases, focusing to achieve aerobic denitrification. This process will minimize emissions of N2O greenhouse gas. The effects of different operating parameters on the reactor performance were studied: cycle duration, AN/OX ratio, pH, dissolved oxygen concentration (DOC), and organic load. The highest inorganic N removal (NiR), close to 70%, was obtained at pH=7.5, low organic load (440mgCOD/(Lday)) and high aeration given by 12h cycle, AN/OX ratio=0.5:1.0 and DOC higher than 4.0mgO2/L. Nitrification followed by high-rate aerobic denitrification took place during the aerobic phase. Aerobic denitrification could be attributed to Tetrad-forming organisms (TFOs) with phenotype of glycogen accumulating organisms using polyhydroxyalkanoate and/or glycogen storage. The proposed AN/OX system constitutes an eco-friendly N removal process providing N2 as the end product.

  11. Acquisition of the Concept "Biodegradable" Through Written Instruction: Pretest and Age Effects.

    ERIC Educational Resources Information Center

    Arganian, Mourad P.; And Others

    The primary purpose of this study/experiment was to determine whether children in the middle elementary grades would be able to learn the concepts "biodegradable agent,""biodegradable material," and "biodegradable process" from a short written lesson. Secondary purposes were to examine the degree to which a pretest, grade level, and sex of the…

  12. Sludge minimization using aerobic/anoxic treatment technology

    SciTech Connect

    Mines, R.O. Jr.; Kalch, R.S.

    1999-07-01

    The objective of this investigation was to demonstrate through a bench-scale study that using an aerobic/anoxic sequence to treat wastewater and biosolids could significantly reduce the production of biosolids (sludge). A bench-scale activated sludge reactor and anoxic digester were operated for approximately three months. The process train consisted of a completely-mixed aerobic reactor with wasting of biosolids to an anoxic digester for stabilization. The system was operated such that biomass produced in the aerobic activated sludge process was wasted to the anoxic digester; and biomass produced in the anoxic digester was wasted back to the activated sludge process. A synthetic wastewater consisting of bacto-peptone nutrient broth was fed to the liquid process train. Influent and effluent to the aerobic biological process train were analytically tested, as were the contents of mixed liquor in the aerobic reactor and anoxic digester. Overall removal efficiencies for the activated sludge process with regard to COD, TKN, NH{sub 3}-N, and alkalinity averaged 91, 89, 98, and 38%, respectively. The overall average sludge production for the aerobic/anoxic process was 24% less than the overall average sludge production from a conventional activated sludge bench-scale system fed the same substrate and operated under similar mean cell residence times.

  13. A novel P450-initiated biphasic process for sustainable biodegradation of benzo[a]pyrene in soil under nutrient-sufficient conditions by the white rot fungus Phanerochaete chrysosporium.

    PubMed

    Bhattacharya, Sukanta S; Syed, Khajamohiddin; Shann, Jodi; Yadav, Jagjit S

    2013-10-15

    High molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) such as benzo[a]pyrene (BaP) are resistant to biodegradation in soil. Conventionally, white rot fungus Phanerochaete chrysosporium has been investigated for HMW-PAH degradation in soil primarily using nutrient-deficient (ligninolytic) conditions, albeit with limited and non-sustainable biodegradation outcomes. In this study, we report development of an alternative novel biphasic process initiated under nutrient-sufficient (non-ligninolytic) culture conditions, by employing an advanced experimental design strategy. During the initial nutrient-sufficient non-ligninolytic phase (16 days), the process showed upregulation (3.6- and 22.3-fold, respectively) of two key PAH-oxidizing P450 monooxygenases pc2 (CYP63A2) and pah4 (CYP5136A3) and formation of typical P450-hydroxylated metabolite. This along with abrogation (84.9%) of BaP degradation activity in response to a P450-specific inhibitor implied key role of these monooxygenases. The subsequent phase triggered on continued incubation (to 25 days) switched the process from non-ligninolytic to ligninolytic resulting in a significantly higher net degradation (91.6% as against 67.4% in the control nutrient-limited set) of BaP with concomitant de novo ligninolytic enzyme expression making it a biphasic process yielding improved sustainable bioremediation of PAH-contaminated soil. To our knowledge this is the first report on development of such biphasic process for bioremediation application of a white rot fungus.

  14. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  15. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  16. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, M.P.; Bessette, B.J.; March, J.; McComb, S.T.

    2000-02-15

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120 F and 140 F in steady state.

  17. Treatment of high salt oxidized modified starch waste water using micro-electrolysis, two-phase anaerobic aerobic and electrolysis for reuse

    NASA Astrophysics Data System (ADS)

    Yi, Xuenong; Wang, Yulin

    2016-08-01

    A combined process of micro-electrolysis, two-phase anaerobic, aerobic and electrolysis was investigated for the treatment of oxidized modified starch wastewater (OMSW). Optimum ranges for important operating variables were experimentally determined and the treated water was tested for reuse in the production process of corn starch. The optimum hydraulic retention time (HRT) of micro-electrolysis, methanation reactor, aerobic process and electrolysis process were 5, 24, 12 and 3 h, respectively. The addition of iron-carbon fillers to the acidification reactor was 200 mg/L while the best current density of electrolysis was 300 A/m2. The biodegradability was improved from 0.12 to 0.34 by micro-electrolysis. The whole treatment was found to be effective with removal of 96 % of the chemical oxygen demand (COD), 0.71 L/day of methane energy recovery. In addition, active chlorine production (15,720 mg/L) was obtained by electrolysis. The advantage of this hybrid process is that, through appropriate control of reaction conditions, effect from high concentration of salt on the treatment was avoided. Moreover, the process also produced the material needed in the production of oxidized starch while remaining emission-free and solved the problem of high process cost.

  18. Biodegradation of 17β-estradiol, estrone, and testosterone in stream sediments

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.; Barber, L.B.; McMahon, P.B.; Gray, J.L.; Kolpin, D.W.

    2009-01-01

    mineralization immediately downstream of the WWTP outfalls were more than double that of upstream samples. E2 mineralization was also observed in water, albeit at insufficient rate to prevent substantial downstream transport in the water column. The results of this study indicate that, in combination with sediment sorption processes which effectively scavenge hydrophobic contaminants from the water column and immobilize them in the vicinity of the WWTP outfall, aerobic biodegradation of reproductive hormones can be an environmentally important mechanism for nonconservative (destructive) attenuation of hormonal endocrine disruptors in effluent-impacted streams.

  19. Biodegradable lignin/polyolefin composite films

    SciTech Connect

    Kosikova, B.; Demjanova, V.; Mikulasova, M.; Lora, J.H.

    1993-12-31

    From the view point of environmental protection, the plastic wastes, especially from packing materials, represent a potential waste problem. Various approaches were examined to develop partially or completely biodegradable plastics. New type of partially biodegradable polyolefins was prepared by blending of polypropylene with lignin, which was recovered in the ALCELL process, an organosolv pulping process that uses ethanol-water as the delignifying agent. Films of blends with up to 10% wt ALCELL lignin, prepared in absence of commercial stabilizers, had acceptable mechanical strengths. The effect of lignin on biodegradability of the composite films was examined by comparison of behaviour of both pure and lignin containing films during treatment with fungus Phanerochaete chrysosporium. It was found that this fungus is able to grow and to produce lignolytic enzymes in the presence of the films containing lignin. Biodegradation of lignin in the composite film was confirmed by the releasing of lignin fragments into the extracellular fluid. Because of measurement of mechanical properties offers a mean of direct estimation of polymer degradation, the degree of biodegradation of the films tested was followed by monitoring of elongation at break. The changes of break at elongation in the course of enzymatic treatment revealed that the lignin/PP composite films are potentially environmentally nonpersisting. The micrographs of the lignin containing films obtained by scanning electron microscopy show the significant changes of the film surface upon degradation with Phanerochaete chrysosporium in contrast to unchanged lignin free film.

  20. Biodegradability enhancement of textile wastewater by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Kim, Tak-Hyun; Lee, Jae-Kwang; Lee, Myun-Joo

    2007-06-01

    Textile wastewater generally contains various pollutants, which can cause problems during biological treatment. Electron beam radiation technology was applied to enhance the biodegradability of textile wastewater for an activated sludge process. The biodegradability (BOD 5/COD) increased at a 1.0 kGy dose. The biorefractory organic compounds were converted into more easily biodegradable compounds such as organic acids having lower molecular weights. In spite of the short hydraulic retention time (HRT) of the activated sludge process, not only high organic removal efficiencies, but also high microbial activities were achieved. In conclusion, textile wastewater was effectively treated by the combined process of electron beam radiation and an activated sludge process.

  1. Changes in iso- and n-alkane distribution during biodegradation of crude oil under nitrate and sulphate reducing conditions.

    PubMed

    Hasinger, Marion; Scherr, Kerstin E; Lundaa, Tserennyam; Bräuer, Leopold; Zach, Clemens; Loibner, Andreas Paul

    2012-02-20

    Crude oil consists of a large number of hydrocarbons with different susceptibility to microbial degradation. The influence of hydrocarbon structure and molecular weight on hydrocarbon biodegradation under anaerobic conditions is not fully explored. In this study oxygen, nitrate and sulphate served as terminal electron acceptors (TEAs) for the microbial degradation of a paraffin-rich crude oil in a freshly contaminated soil. During 185 days of incubation, alkanes from n-C11 to n-C39, three n- to iso-alkane ratios commonly used as weathering indicators and the unresolved complex mixture (UCM) were quantified and statistically analyzed. The use of different TEAs for hydrocarbon degradation resulted in dissimilar degradative patterns for n- and iso-alkanes. While n-alkane biodegradation followed well-established patterns under aerobic conditions, lower molecular weight alkanes were found to be more recalcitrant than mid- to high-molecular weight alkanes under nitrate-reducing conditions. Biodegradation with sulphate as the TEA was most pronounced for long-chain (n-C32 to n-C39) alkanes. The observation of increasing ratios of n-C17 to pristane and of n-C18 to phytane provides first evidence of the preferential degradation of branched over normal alkanes under sulphate reducing conditions. The formation of distinctly different n- and iso-alkane biodegradation fingerprints under different electron accepting conditions may be used to assess the occurrence of specific degradation processes at a contaminated site. The use of n- to iso-alkane ratios for this purpose may require adjustment if applied for anaerobic sites.

  2. Effect of surfactants on PAH biodegradation by a bacterial consortium and on the dynamics of the bacterial community during the process.

    PubMed

    González, N; Simarro, R; Molina, M C; Bautista, L F; Delgado, L; Villa, J A

    2011-10-01

    The aim of this work was to evaluate the effect of a non-biodegradable (Tergitol NP-10) and a biodegradable (Tween-80) surfactant on growth, degradation rate and microbial dynamics of a polycyclic aromatic hydrocarbon (PAHs) degrading consortium (C2PL05) from a petroleum polluted soil, applying cultivable and non cultivable techniques. Growth and degradation rate were significantly lower with Tergitol NP-10 than that with Tween-80. Toxicity did not show any significant reduction with Tergitol NP-10 whereas with Tween-80 toxicity was almost depleted (30%) after 40 days. Regarding to the cultured bacteria, Pseudomonas and Stenotrophomonas groups were dominant during PAH degradation with Tergitol NP-10, whereas Enterobacter and Stenotrophomonas were dominant with Tween-80. DGGE analyses (PRIMER and MDS) showed that bacteria composition was more similar between treatments when PAHs were consumed than when PAHs concentration was still high. Community changes between treatments were a consequence of Pseudomonas sp., Sphingomonas sp., Sphingobium sp. and Agromonas sp.

  3. Influence of an aniline supplement on the stability of aerobic granular sludge.

    PubMed

    Dai, Yajie; Jiang, Yixin; Su, Haijia

    2015-10-01

    In order to evaluate the stability of aerobic granules in a toxic environment, this study discussed the influence of an aniline supplement on the properties and microbial community of aerobic granules. In the early stages of sequencing batch reactor (SBR) operation, an aniline supplement slightly affected the properties of the aerobic granules (strength, growth rate, SVI and so on). This effect was thereafter removed because of a change in the microbial community and the structure of aerobic granules: with the present of aniline, microbes with biodegradation ability appeared and gathered in the aerobic granules and the aerobic granules densified and settled faster as their SVI decreased to 35 mL/g and settling velocity increased to 41.56 m/h. When a synthetic waste water containing acetate as carbon source was used as influent, aniline (10-500 mg/L) could be degraded in 6 h, at a rate as high as 37.5 mg aniline/(L·h), with a removal rate in excess of 90%, while the effluent COD fell below 100 mg/L from the initial about 2000 mg/L. The aerobic granules cultured by acetate were compact, stable and resistant to aniline.

  4. Biodegradability and denitrification potential of settleable chemical oxygen demand in domestic wastewater.

    PubMed

    Tas, Didem Okutman; Karahan, Ozlem; Insel, Güçlü; Ovez, Süleyman; Orhon, Derin; Spanjers, Henri

    2009-07-01

    The effect of settling on mass balance and biodegradation characteristics of domestic wastewater and on denitrification potential was studied primarily using model calibration and evaluation of oxygen uptake rate profiles. Raw domestic wastewater was settled for a period of 30 minutes and a period of 2 hours to assess the effect of primary settling on wastewater characterization and composition. Mass balances in the system were made to evaluate the effect of primary settling on major parameters. Primary settling of the selected raw wastewater for 2 hours resulted in the removal of 32% chemical oxygen demand (COD), 9% total Kjeldahl nitrogen, 9% total phosphorus, and 47% total suspended solids. Respirometric analysis identified COD removed by settling as a new COD fraction, namely settleable slowly biodegradable COD (X(ss)), characterized by a hydrolysis rate of 1.0 day(-1) and a hydrolysis half-saturation coefficient of 0.08. A model simulation to test the fate and availability of suspended (X(s)) and settleable (X(ss)) COD fractions as carbon sources for denitrification showed that both particulate COD components were effectively removed aerobically at sludge ages higher than 1.5 to 2.0 days. Under anoxic conditions, the biodegradation of both COD fractions was reduced, especially below an anoxic sludge retention time of 3.0 days. Consequently, modeling results revealed that the settleable COD removed by primary settling could represent up to approximately 40% of the total denitrification potential of the system, depending on the specific configuration selected for the nitrogen removal process. This way, the results showed the significant effect of primary settling on denitrification, indicating that the settleable COD fraction could contribute an additional carbon source in systems where the denitrification potential associated with the influent becomes rate-limiting for the denitrification efficiency.

  5. 3-Chloro-1,2-propanediol biodegradation by Ca-alginate immobilized Pseudomonas putida DSM 437 cells applying different processes: mass transfer effects.

    PubMed

    Konti, Aikaterini; Mamma, Diomi; Hatzinikolaou, Dimitios G; Kekos, Dimitris

    2016-10-01

    3-Chloro-1,2-propanediol (3-CPD) biodegradation by Ca-alginate immobilized Pseudomonas putida cells was performed in batch system, continuous stirred tank reactor (CSTR), and packed-bed reactor (PBR). Batch system exhibited higher biodegradation rates and 3-CPD uptakes compared to CSTR and PBR. The two continuous systems (CSTR and PBR) when compared at 200 mg/L 3-CPD in the inlet exhibited the same removal of 3-CPD at steady state. External mass-transfer limitations are found negligible at all systems examined, since the observable modulus for external mass transfer Ω ≪ 1 and the Biot number Bi > 1. Intra-particle diffusion resistance had a significant effect on 3-CPD biodegradation in all systems studied, but to a different extent. Thiele modulus was in the range of 2.5 in batch system, but it was increased at 11 when increasing cell loading in the beads, thus lowering significantly the respective effectiveness factor. Comparing the systems at the same cell loading in the beads PBR was less affected by internal diffusional limitations compared to CSTR and batch system, and, as a result, exhibited the highest overall effectiveness factor.

  6. Effects of Bioreactor Retention Time on Aerobic Microbial Decomposition of CELSS Crop Residues

    NASA Technical Reports Server (NTRS)

    Strayer, R. F.; Finger, B. W.; Alazraki, M. P.

    1997-01-01

    The focus of resource recovery research at the KSC-CELSS Breadboard Project has been the evaluation of microbiologically mediated biodegradation of crop residues by manipulation of bioreactor process and environmental variables. We will present results from over 3 years of studies that used laboratory- and breadboard-scale (8 and 120 L working volumes, respectively) aerobic, fed-batch, continuous stirred tank reactors (CSTR) for recovery of carbon and minerals from breadboard grown wheat and white potato residues. The paper will focus on the effects of a key process variable, bioreactor retention time, on response variables indicative of bioreactor performance. The goal is to determine the shortest retention time that is feasible for processing CELSS crop residues, thereby reducing bioreactor volume and weight requirements. Pushing the lower limits of bioreactor retention times will provide useful data for engineers who need to compare biological and physicochemical components. Bioreactor retention times were manipulated to range between 0.25 and 48 days. Results indicate that increases in retention time lead to a 4-fold increase in crop residue biodegradation, as measured by both dry weight losses and CO2 production. A similar overall trend was also observed for crop residue fiber (cellulose and hemicellulose), with a noticeable jump in cellulose degradation between the 5.3 day and 10.7 day retention times. Water-soluble organic compounds (measured as soluble TOC) were appreciably reduced by more than 4-fold at all retention times tested. Results from a study of even shorter retention times (down to 0.25 days), in progress, will also be presented.

  7. Effects of bioreactor retention time on aerobic microbial decomposition of CELSS crop residues

    NASA Astrophysics Data System (ADS)

    Strayer, R. F.; Finger, B. W.; Alazraki, M. P.

    1997-01-01

    The focus of resource recovery research at the KSC-CELSS Breadboard Project has been the evaluation of microbiologically mediated biodegradation of crop residues by manipulation of bioreactor process and environmental variables. We will present results from over 3 years of studies that used laboratory- and breadboard-scale (8 and 120 L working volumes, respectively) aerobic, fed-batch, continuous stirred tank reactors (CSTR) for recovery of carbon and minerals from breadboard grown wheat and white potato residues. The paper will focus on the effects of a key process variable--bioreactor retention time--on response variables indicative of bioreactor performance. The goal is to determine the shortest retention time that is feasible for processing CELSS crop residues, thereby reducing bioreactor volume and weight requirements. Pushing the lower limits of bioreactor retention times will provide useful data for engineers who need to compare biological and physicochemical components. Bioreactor retention times were manipulated to range between 0.25 and 48 days. Results indicate that increases in retention time lead to a 4-fold increase in crop residue biodegradation, as measured by both dry weight losses and CO_2 production. A similar overall trend was also observed for crop residue fiber (cellulose and hemicellulose), with a noticeable jump in cellulose degradation between the 5.3 day and 10.7 day retention times. Water-soluble organic compounds (measured as soluble TOC) were appreciably reduced by more than 4-fold at all retention times tested. Results from a study of even shorter retention times (down to 0.25 days), in progress, will also be presented.

  8. Modeling microbiological and chemical processes in municipal solid waste bioreactor, Part I: Development of a three-phase numerical model BIOKEMOD-3P.

    PubMed

    Gawande, Nitin A; Reinhart, Debra R; Yeh, Gour-Tsyh

    2010-02-01

    The numerical computer models that simulate municipal solid waste (MSW) bioreactor landfills have mainly two components--a biodegradation process module and a multi-phase flow module. The biodegradation model describes the chemical and microbiological processes. The models available to date include predefined solid waste biodegradation reactions and participating species. Some of these models allow changing the basic composition of solid waste. In a bioreactor landfill several processes like anaerobic and aerobic solids biodegradation, nitrogen and sulfate related processes, precipitation and dissolution of metals, and adsorption and gasification of various anthropogenic organic compounds occur simultaneously. These processes may involve reactions of several species and the available biochemical models for solid waste biodegradation do not provide users with the flexibility to simulate these processes by choice. This paper presents the development of a generalized biochemical process model BIOKEMOD-3P which can accommodate a large number of species and process reactions. This model is able to simulate bioreactor landfill operation in a completely mixed condition, when coupled with a multi-phase model it will be able to simulate a full-scale bioreactor landfill. This generalized biochemical model can simulate laboratory and pilot-scale operations in order to determine biochemical parameters important for simulation of full-scale operations.

  9. Life in the slow lane; biogeochemistry of biodegraded petroleum containing reservoirs and implications for energy recovery and carbon management

    PubMed Central

    Head, Ian M.; Gray, Neil D.; Larter, Stephen R.

    2014-01-01

    Our understanding of the processes underlying the formation of heavy oil has been transformed in the last decade. The process was once thought to be driven by oxygen delivered to deep petroleum reservoirs by meteoric water. This paradigm has been replaced by a view that the process is anaerobic and frequently associated with methanogenic hydrocarbon degradation. The thermal history of a reservoir exerts a fundamental control on the occurrence of biodegraded petroleum, and microbial activity is focused at the base of the oil column in the oil water transition zone, that represents a hotspot in the petroleum reservoir biome. Here we present a synthesis of new and existing microbiological, geochemical, and biogeochemical data that expands our view of the processes that regulate deep life in petroleum reservoir ecosystems and highlights interactions of a range of biotic and abiotic factors that determine whether petroleum is likely to be biodegraded in situ, with important consequences for oil exploration and production. Specifically we propose that the salinity of reservoir formation waters exerts a key control on the occurrence of biodegraded heavy oil reservoirs and introduce the concept of palaeopickling. We also evaluate the interaction between temperature and salinity to explain the occurrence of non-degraded oil in reservoirs where the temperature has not reached the 80–90°C required for palaeopasteurization. In addition we evaluate several hypotheses that might explain the occurrence of organisms conventionally considered to be aerobic, in nominally anoxic petroleum reservoir habitats. Finally we discuss the role of microbial processes for energy recovery as we make the transition from fossil fuel reliance, and how these fit within the broader socioeconomic landscape of energy futures. PMID:25426105

  10. Exercise, Animal Aerobics, and Interpretation?

    ERIC Educational Resources Information Center

    Oliver, Valerie

    1996-01-01

    Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…