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Elsey JL, Miller EL, Christ JA, Abriola LM. On the reliable estimation of sequential Monod kinetic parameters. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 262:104323. [PMID: 38430692 DOI: 10.1016/j.jconhyd.2024.104323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 02/15/2024] [Accepted: 02/19/2024] [Indexed: 03/05/2024]
Abstract
While dozens of studies have attempted to estimate the Monod kinetic parameters of microbial reductive dechlorination, published values in the literature vary by 2-6 orders of magnitude. This lack of consensus can be attributed in part to limitations of both experimental design and parameter estimation techniques. To address these issues, Hamiltonian Monte Carlo was used to produce more than one million sets of realistic simulated microcosm data under a variety of experimental conditions. These data were then employed in model fitting experiments using a number of parameter estimation algorithms for determining Monod kinetic parameters. Analysis of data from conventional triplicate microcosms yielded parameter estimates characterized by high collinearity, resulting in poor estimation accuracy and precision. Additionally, confidence intervals computed by commonly used classical regression analysis techniques contained true parameter values much less frequently than their nominal confidence levels. Use of an alternative experimental design, requiring the same number of analyses as conventional experiments but comprised of microcosms with varying initial chlorinated ethene concentrations, is shown to result in order-of-magnitude decreases in parameter uncertainty. A Metropolis algorithm which can be run on a typical personal computer is demonstrated to return more reliable parameter interval estimates.
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Affiliation(s)
- Jack L Elsey
- Department of Civil and Environmental Engineering, Tufts University, Medford, MA 02155, USA
| | - Eric L Miller
- Department of Electrical and Computer Engineering, Tufts University, Medford, MA 02155, USA
| | | | - Linda M Abriola
- School of Engineering, Brown University, Providence, RI 02912, USA.
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2
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Wu Z, Man Q, Niu H, Lyu H, Song H, Li R, Ren G, Zhu F, Peng C, Li B, Ma X. Recent advances and trends of trichloroethylene biodegradation: A critical review. Front Microbiol 2022; 13:1053169. [PMID: 36620007 PMCID: PMC9813602 DOI: 10.3389/fmicb.2022.1053169] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022] Open
Abstract
Trichloroethylene (TCE) is a ubiquitous chlorinated aliphatic hydrocarbon (CAH) in the environment, which is a Group 1 carcinogen with negative impacts on human health and ecosystems. Based on a series of recent advances, the environmental behavior and biodegradation process on TCE biodegradation need to be reviewed systematically. Four main biodegradation processes leading to TCE biodegradation by isolated bacteria and mixed cultures are anaerobic reductive dechlorination, anaerobic cometabolic reductive dichlorination, aerobic co-metabolism, and aerobic direct oxidation. More attention has been paid to the aerobic co-metabolism of TCE. Laboratory and field studies have demonstrated that bacterial isolates or mixed cultures containing Dehalococcoides or Dehalogenimonas can catalyze reductive dechlorination of TCE to ethene. The mechanisms, pathways, and enzymes of TCE biodegradation were reviewed, and the factors affecting the biodegradation process were discussed. Besides, the research progress on material-mediated enhanced biodegradation technologies of TCE through the combination of zero-valent iron (ZVI) or biochar with microorganisms was introduced. Furthermore, we reviewed the current research on TCE biodegradation in field applications, and finally provided the development prospects of TCE biodegradation based on the existing challenges. We hope that this review will provide guidance and specific recommendations for future studies on CAHs biodegradation in laboratory and field applications.
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Affiliation(s)
- Zhineng Wu
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Quanli Man
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Hanyu Niu
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Honghong Lyu
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Haokun Song
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Rongji Li
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Gengbo Ren
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Fujie Zhu
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Chu Peng
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - Benhang Li
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China
| | - Xiaodong Ma
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, China,*Correspondence: Xiaodong Ma,
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Puigserver D, Herrero J, Nogueras X, Cortés A, Parker BL, Playà E, Carmona JM. Biotic and abiotic reductive dechlorination of chloroethenes in aquitards. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 816:151532. [PMID: 34752872 DOI: 10.1016/j.scitotenv.2021.151532] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Chlorinated solvents occur as dense nonaqueous phase liquid (DNAPL) or as solutes when dissolved in water. They are present in many pollution sites in urban and industrial areas. They are toxic, carcinogenic, and highly recalcitrant in aquifers and aquitards. In the latter case, they migrate by molecular diffusion into the matrix. When aquitards are fractured, chlorinated solvents also penetrate as a free phase through the fractures. The main objective of this study was to analyze the biogeochemical processes occurring inside the matrix surrounding fractures and in the joint-points zones. The broader implications of this objective derive from the fact that, incomplete natural degradation of contaminants in aquitards generates accumulation of daughter products. This causes steep concentration gradients and back-diffusion fluxes between aquitards and high hydraulic conductivity layers. This offers opportunities to develop remediation strategies based, for example, on the coupling of biotic and reactive abiotic processes. The main results showed: 1) Degradation occurred especially in the matrix adjacent to the orthogonal network of fractures and textural heterogeneities, where texture contrasts favored microbial development because these zones constituted ecotones. 2) A dechlorinating bacterium not belonging to the Dehalococcoides genus, namely Propionibacterium acnes, survived under the high concentrations of dissolved perchloroethene (PCE) in contact with the PCE-DNAPL and was able to degrade it to trichloroethene (TCE). Dehalococcoides genus was able to conduct PCE reductive dechlorination at least up to cis-1,2-dichloroethene (cDCE), which shows again the potential of the medium to degrade chloroethenes in aquitards. 3) Degradation of PCE in the matrix resulted from the coupling of reactive abiotic and biotic processes-in the first case, promoted by Fe2+ sorbed to iron oxides, and in the latter case, related to dechlorinating microorganisms. The dechlorination resulting from these coupling processes is slow and limited by the need for an adequate supply of electron donors.
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Affiliation(s)
- Diana Puigserver
- Department of Mineralogy, Petrology and Applied Geology, Faculty of Earth Sciences, University of Barcelona (UB), Water Research Institute (IdRA-UB), Serra Húnter Tenure-elegible Lecturer, C/ Martí i Franquès, s/n, E-08028 Barcelona, Spain.
| | - Jofre Herrero
- Department of Mineralogy, Petrology and Applied Geology, Faculty of Earth Sciences, University of Barcelona (UB), Water Research Institute (IdRA-UB). C/ Martí i Franquès, s/n, E-08028 Barcelona, Spain.
| | - Xènia Nogueras
- Department of Mineralogy, Petrology and Applied Geology, Faculty of Earth Sciences, University of Barcelona (UB). C/ Martí i Franquès, s/n, E-08028 Barcelona, Spain; Health Section of the City Council of Mataró (Barcelona), Specialized Support Technician, Carrer de la Riera, 48, 08301 Mataró, Barcelona, Spain.
| | - Amparo Cortés
- Department of Biology, Health and Environment, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain.
| | - Beth L Parker
- School of Engineering, University of Guelph, 50, Stone Road East, Guelph, N1G 2W1, Ontario, Canada.
| | - E Playà
- Department of Mineralogy, Petrology and Applied Geology, Faculty of Earth Sciences, University of Barcelona (UB). C/ Martí i Franquès, s/n, E-08028 Barcelona, Spain.
| | - José M Carmona
- Department of Mineralogy, Petrology and Applied Geology, Faculty of Earth Sciences, University of Barcelona (UB), Water Research Institute (IdRA-UB). C/ Martí i Franquès, s/n, E-08028 Barcelona, Spain.
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Liu Y, Chen H, Zhao L, Li Z, Yi X, Guo T, Cao X. Enhanced trichloroethylene biodegradation: Roles of biochar-microbial collaboration beyond adsorption. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 792:148451. [PMID: 34157525 DOI: 10.1016/j.scitotenv.2021.148451] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
Trichloroethylene (TCE) is a pollutant widely found in groundwater, especially in the heavily contaminated industrial sites. Biological dechlorination method is environmentally friendly and low-cost. However, microorganisms grow slowly and their activity is susceptible to environmental fluctuations. This study used biochar as an additive to promote anaerobic biodegradation of TCE with mixed culture. Results showed that biochar with dose of 0.1-0.4% (w/v) brought a rapid initial decrease of TCE concentration by 39.4-88.8% in 24 h via adsorption mechanism. Biochar produced at 500 °C pyrolysis temperature (BC500) achieved the highest TCE adsorption in comparison to BC300 and BC700. Subsequently, a significantly shortened microbial stagnation phase (from 85 h to 37 h) was observed in the system with the presence of biochar. During the exponential growth phase, BC700 outperformed BC300 and BC500 in terms of TCE degradation efficiency. Electrochemical analysis demonstrated that BC700 possessed the greatest electron transfer capability. Finally, biochar shortened the time for achieving 100% removal of TCE by 54.5-69.7% (from approximate 330 h to 100-150 h). Even at high concentration of TCE (20-30 mg·L-1) that could lead to serious microbial growth inhibition, the TCE degradation efficiency could be recovered in the presence of BC500. The high-throughput sequencing data revealed that biochar promoted the relative abundance of co-metabolizing dechlorinating microorganisms (Pseudomonas, Burkholderia) in the aqueous solution, and simultaneously led to the selective colonization of reductive dechlorinating microorganisms (Enterobacteriaceae, Clostridium) attached on biochar surface. On the other hand, biochar addition decreased the relative abundance of hydrogen-competing microorganisms, thereby forming an efficient co-metabolism-reductive dechlorination system. These findings allow a better understanding of the promotion mechanism of biochar for microbial dechlorination technology supporting the biochar-assisted bioremediation in practice.
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Affiliation(s)
- Yang Liu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hao Chen
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ling Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 201306, China.
| | - Zhaopeng Li
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xionghai Yi
- Shanghai Customs District P. R. China, Minsheng Road No. 1208, Shanghai 200135, China
| | - Tianbao Guo
- Hebei Xiongan Mairong Environmental Protection Co. Ltd, Xiongan 071000, China
| | - Xinde Cao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai 201306, China
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5
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Dupnock TL, Deshusses MA. Detailed investigations of dissolved hydrogen and hydrogen mass transfer in a biotrickling filter for upgrading biogas. BIORESOURCE TECHNOLOGY 2019; 290:121780. [PMID: 31325841 DOI: 10.1016/j.biortech.2019.121780] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/05/2019] [Accepted: 07/06/2019] [Indexed: 06/10/2023]
Abstract
This study investigated the hydrogen mass transfer limitations in a biotrickling filter inoculated with hydrogenotrophic methanogens for biogas upgrading. A highly sensitive dissolved hydrogen probe allowed measuring concentrations in real-time. Experiments were conducted to test the mass transfer resistance in the gas and liquid films. Results demonstrated that the main resistance resides in the trickling liquid film and that promoting direct gas-biofilm mass transfer could improve upgrading performance by about 20%. Increasing the gas velocity (keeping a constant gas contact time) lowered the upgrading capacity. This was explained by the lowering of the concentration to the average concentration throughout the bed, which resulted a lower reaction rate. At extended gas contact times, the bioreactor shifted from microbial to diffusion limitation, causing lower upgrading capacities. Methane-containing biogas mimics (H2/CH4/CO2) were successfully upgraded to natural gas pipeline standards (>97% methane) with only minor performance reduction compared to upgrading just a H2/CO2 mixture.
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Affiliation(s)
- Trisha L Dupnock
- Department of Civil and Environmental Engineering, 127C, Hudson Hall, Box 90287, Duke University, Durham, NC, 27708-0287, USA
| | - Marc A Deshusses
- Department of Civil and Environmental Engineering, 127C, Hudson Hall, Box 90287, Duke University, Durham, NC, 27708-0287, USA.
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6
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Pilot-Scale Evaluation of a Permeable Reactive Barrier with Compost and Brown Coal to Treat Groundwater Contaminated with Trichloroethylene. WATER 2019. [DOI: 10.3390/w11091922] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study evaluates, under field conditions, the efficiency of a permeable reactive barrier (PRB) with compost and brown coal to remove trichloroethylene (TCE) (109 µg/L) from contaminated groundwater. Three stainless steel boxes (1.2 × 0.5 × 0.5 m) with the brown coal-compost mixture at three different mixing ratios of 1:1, 1:3, and 1:5 (by volume) were installed to simulate the PRB. Groundwater from the TCE-contaminated aquifer was pumped into the system at a flow rate of 3.6 L/h. Residence times in the boxes were of: 25, 20, 10 h, respectively. Effluent samples were analyzed for TCE and its daughter products: dichloroethylene (DCE), vinyl chloride (VC) and ethane. During the 198-day experimental period TCE concentrations in groundwater decreased below ≤1.1 µg/L, i.e., much lower than groundwater and drinking water standards in Poland. After 16 days cis-1,2-DCE was monitored indicating possible reductive dechlorination of TCE. However, complete transformation of TCE into non-toxic byproducts was not evidenced during the time of experiments, indicating that reductive dechlorination slowed down or stopped at DCE, and that the designed residence times were not long enough to allow the complete dechlorination process.
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7
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Chau ATT, Lee M, Adrian L, Manefield MJ. Syntrophic Partners Enhance Growth and Respiratory Dehalogenation of Hexachlorobenzene by Dehalococcoides mccartyi Strain CBDB1. Front Microbiol 2018; 9:1927. [PMID: 30186256 PMCID: PMC6113397 DOI: 10.3389/fmicb.2018.01927] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 07/30/2018] [Indexed: 11/19/2022] Open
Abstract
This study investigated syntrophic interactions between chlorinated benzene respiring Dehalococcoides mccartyi strain CBDB1 and fermenting partners (Desulfovibrio vulgaris, Syntrophobacter fumaroxidans, and Geobacter lovleyi) during hexachlorobenzene respiration. Dechlorination rates in syntrophic co-cultures were enhanced 2-3 fold compared to H2 fed CBDB1 pure cultures (0.23 ± 0.04 μmol Cl− day−1). Syntrophic partners were also able to supply cobalamins to CBDB1, albeit with 3–10 fold lower resultant dechlorination activity compared to cultures receiving exogenous cyanocobalamin. Strain CBDB1 pure cultures accumulated ~1 μmol of carbon monoxide per 87.5 μmol Cl− released during hexachlorobenzene respiration resulting in decreases in dechlorination activity. The syntrophic partners investigated were shown to consume carbon monoxide generated by CBDB1, thus relieving carbon monoxide autotoxicity. Accumulation of lesser chlorinated chlorobenzene congeners (1,3- and 1,4-dichlorobenzene and 1,3,5-trichlorobenzene) also inhibited dechlorination activity and their removal from the headspace through adsorption to granular activated carbon was shown to restore activity. Proteomic analysis revealed co-culturing strain CBDB1 with Geobacter lovleyi upregulated CBDB1 genes associated with reductive dehalogenases, hydrogenases, formate dehydrogenase, and ribosomal proteins. These data provide insight into CBDB1 ecology and inform strategies for application of CBDB1 in ex situ hexachlorobenzene destruction technologies.
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Affiliation(s)
- Anh T T Chau
- College of Agriculture and Applied Biology, Cantho University, Can Tho, Vietnam.,School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Matthew Lee
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Lorenz Adrian
- Department Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Michael J Manefield
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, Australia.,School of Chemical Engineering, University of New South Wales, Sydney, NSW, Australia
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8
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Delgado AG, Fajardo-Williams D, Bondank E, Esquivel-Elizondo S, Krajmalnik-Brown R. Coupling Bioflocculation of Dehalococcoides mccartyi to High-Rate Reductive Dehalogenation of Chlorinated Ethenes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:11297-11307. [PMID: 28914537 DOI: 10.1021/acs.est.7b03097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Continuous bioreactors operated at low hydraulic retention times have rarely been explored for reductive dehalogenation of chlorinated ethenes. The inability to consistently develop such bioreactors affects the way growth approaches for Dehalococcoides mccartyi bioaugmentation cultures are envisioned. It also affects interpretation of results from in situ continuous treatment processes. We report bioreactor performance and dehalogenation kinetics of a D. mccartyi-containing consortium in an upflow bioreactor. When fed synthetic groundwater at 11-3.6 h HRT, the upflow bioreactor removed >99.7% of the influent trichloroethene (1.5-2.8 mM) and produced ethene as the main product. A trichloroethene removal rate of 98.51 ± 0.05 me- equiv L-1 d-1 was achieved at 3.6 h HRT. D. mccartyi cell densities were 1013 and 1012 16S rRNA gene copies L-1 in the bioflocs and planktonic culture, respectively. When challenged with a feed of natural groundwater containing various competing electron acceptors and 0.3-0.4 mM trichloroethene, trichloroethene removal was sustained at >99.6%. Electron micrographs revealed that D. mccartyi were abundant within the bioflocs, not only in multispecies structures, but also as self-aggregated microcolonies. This study provides fundamental evidence toward the feasibility of upflow bioreactors containing D. mccartyi as high-density culture production tools or as a high-rate, real-time remediation biotechnology.
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Affiliation(s)
- Anca G Delgado
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University , Tempe, Arizona 85287-5701, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University , Tempe, Arizona 85287-3005, United States
| | - Devyn Fajardo-Williams
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University , Tempe, Arizona 85287-5701, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University , Tempe, Arizona 85287-3005, United States
| | - Emily Bondank
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University , Tempe, Arizona 85287-5701, United States
| | - Sofia Esquivel-Elizondo
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University , Tempe, Arizona 85287-5701, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University , Tempe, Arizona 85287-3005, United States
| | - Rosa Krajmalnik-Brown
- Biodesign Swette Center for Environmental Biotechnology, Arizona State University , Tempe, Arizona 85287-5701, United States
- School of Sustainable Engineering and the Built Environment, Arizona State University , Tempe, Arizona 85287-3005, United States
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9
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Torresi E, Escolà Casas M, Polesel F, Plósz BG, Christensson M, Bester K. Impact of external carbon dose on the removal of micropollutants using methanol and ethanol in post-denitrifying Moving Bed Biofilm Reactors. WATER RESEARCH 2017; 108:95-105. [PMID: 27871747 DOI: 10.1016/j.watres.2016.10.068] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 06/06/2023]
Abstract
Addition of external carbon sources to post-denitrification systems is frequently used in wastewater treatment plants to enhance nitrate removal. However, little is known about the fate of micropollutants in post-denitrification systems and the influence of external carbon dosing on their removal. In this study, we assessed the effects of two different types and availability of commonly used carbon sources -methanol and ethanol- on the removal of micropollutants in biofilm systems. Two laboratory-scale moving bed biofilm reactors (MBBRs), containing AnoxKaldnes K1 carriers with acclimated biofilm from full-scale systems, were operated in continuous-flow using wastewater dosed with methanol and ethanol, respectively. Batch experiments with 22 spiked pharmaceuticals were performed to assess removal kinetics. Acetyl-sulfadiazine, atenolol, citalopram, propranolol and trimethoprim were easily biotransformed in both MBBRs (biotransformations rate constants kbio between 1.2 and 12.9 L gbiomass-1 d-1), 13 compounds were moderately biotransformed (rate constants between 0.2 and 2 L gbiomass-1 d-1) and 4 compounds were recalcitrant. The methanol-dosed MBBR showed higher kbio (e.g., 1.5-2.5-fold) than in the ethanol-dosed MBBR for 9 out of the 22 studied compounds, equal kbio for 10 compounds, while 3 compounds (i.e., targeted sulfonamides) were biotransformed faster in the ethanol-dosed MBBR. While biotransformation of most of the targeted compounds followed first-order kinetics, removal of venlafaxine, carbamazepine, sulfamethoxazole and sulfamethizole could be described with a cometabolic model. Analyses of the microbial composition in the biofilms using 16S rRNA amplicon sequencing revealed that the methanol-dosed MBBR contained higher microbial richness than the one dosed with ethanol, suggesting that improved biotransformation of targeted compounds could be associated with higher microbial richness. During continuous-flow operation, at conditions representative of full-scale denitrification systems (hydraulic residence time = 2 h), the removal efficiencies of micropollutants were below 35% in both MBBRs, with the exception of atenolol and trimethoprim (>80%). Overall, this study demonstrated that MBBRs used for post-denitrification could be optimized to enhance the biotransformation of a number of micropollutants by accounting for optimal carbon sources and extended residence time.
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Affiliation(s)
- Elena Torresi
- Veolia Water Technologies AnoxKaldnes, Klosterängsvägen 11A, SE-226 47, Lund, Sweden; Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet B115, 2800, Kgs. Lyngby, Denmark
| | - Mònica Escolà Casas
- Department of Environmental Science, Århus University, Frederiksborgvej 399, 4000, Roskilde, Denmark
| | - Fabio Polesel
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet B115, 2800, Kgs. Lyngby, Denmark
| | - Benedek G Plósz
- Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet B115, 2800, Kgs. Lyngby, Denmark.
| | - Magnus Christensson
- Veolia Water Technologies AnoxKaldnes, Klosterängsvägen 11A, SE-226 47, Lund, Sweden.
| | - Kai Bester
- Department of Environmental Science, Århus University, Frederiksborgvej 399, 4000, Roskilde, Denmark.
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10
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Liu L, Binning PJ, Smets BF. Evaluating alternate biokinetic models for trace pollutant cometabolism. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:2230-6. [PMID: 25546565 DOI: 10.1021/es5035393] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Mathematical models of cometabolic biodegradation kinetics can improve our understanding of the relevant microbial reactions and allow us to design in situ or in-reactor applications of cometabolic bioremediation. A variety of models are available, but their ability to describe experimental data has not been systematically evaluated for a variety of operational/experimental conditions. Here five different models were considered: first-order; Michaelis-Menten; reductant; competition; and combined models. The models were assessed on their ability to fit data from simulated batch experiments covering a realistic range of experimental conditions. The simulated observations were generated by using the most complex model structure and parameters based on the literature, with added experimental error. Three criteria were used to evaluate model fit: ability to fit the simulated experimental data, identifiability of parameters using a colinearity analysis, and suitability of the model size and complexity using the Bayesian and Akaike Information criteria. Results show that no single model fits data well for a range of experimental conditions. The reductant model achieved best results, but required very different parameter sets to simulate each experiment. Parameter nonuniqueness was likely to be due to the parameter correlation. These results suggest that the cometabolic models must be further developed if they are to reliably simulate experimental and operational data.
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Affiliation(s)
- Li Liu
- Department of Environmental Engineering, Technical, University of Denmark , Bygningstorvet 115, 2800 Kgs.Lyngby, Denmark
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11
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Karataş S, Hasar H, Taşkan E, Özkaya B, Şahinkaya E. Bio-reduction of tetrachloroethen using a H2-based membrane biofilm reactor and community fingerprinting. WATER RESEARCH 2014; 58:21-28. [PMID: 24731873 DOI: 10.1016/j.watres.2014.03.053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 03/18/2014] [Accepted: 03/19/2014] [Indexed: 06/03/2023]
Abstract
Chlorinated ethenes in drinking water could be reductively dechlorinated to non-toxic ethene by using a hydrogen based membrane biofilm reactor (H2-MBfR) under denitrifying conditions as it provides an appropriate environment for dechlorinating bacteria in biofilm communities. This study evaluates the reductive dechlorination of perchloroethene (PCE) to non-toxic ethene (ETH) and comparative community analysis of the biofilm grown on the gas permeable membrane fibers. For these purposes, three H2-MBfRs receiving three different chlorinated ethenes (PCE, TCE and DCE) were operated under different hydraulic retention times (HRTs) and H2 pressures. Among these reactors, the H2-MBfR fed with PCE (H2-MBfR 1) accomplished a complete dechlorination, whereas cis-DCE accumulated in the TCE receiving H2-MBfR 2 and no dechlorination was detected in the DCE receiving H2-MBfR 3. The results showed that 95% of PCE dechlorinated to ETH together with over 99.8% dechlorination efficiency. Nitrate was the preferred electron acceptor as the most of electrons generated from H2 oxidation used for denitrification and dechlorination started under nitrate deficient conditions at increased H2 pressures. PCR-DGGE analysis showed that Dehalococcoides were present in autotrophic biofilm community dechlorinating PCE to ethene, and RDase genes analysis revealed that pceA, tceA, bvcA and vcrA, responsible for complete dechlorination step, were available in Dehalococcoides strains.
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Affiliation(s)
| | - Halil Hasar
- Fırat University, Faculty of Engineering, Department of Environmental Engineering, 23119 Elazığ, Turkey.
| | - Ergin Taşkan
- Fırat University, Faculty of Engineering, Department of Environmental Engineering, 23119 Elazığ, Turkey.
| | - Bestamin Özkaya
- Yıldız Technical University, Department of Environmental Engineering, İstanbul, Turkey.
| | - Erkan Şahinkaya
- Istanbul Medeniyet University, Department of Bioengineering, İstanbul, Turkey.
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Delgado AG, Fajardo-Williams D, Popat SC, Torres CI, Krajmalnik-Brown R. Successful operation of continuous reactors at short retention times results in high-density, fast-rate Dehalococcoides dechlorinating cultures. Appl Microbiol Biotechnol 2013; 98:2729-37. [PMID: 24085396 DOI: 10.1007/s00253-013-5263-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/11/2013] [Accepted: 09/12/2013] [Indexed: 10/26/2022]
Abstract
The discovery of Dehalococcoides mccartyi reducing perchloroethene and trichloroethene (TCE) to ethene was a key landmark for bioremediation applications at contaminated sites. D. mccartyi-containing cultures are typically grown in batch-fed reactors. On the other hand, continuous cultivation of these microorganisms has been described only at long hydraulic retention times (HRTs). We report the cultivation of a representative D. mccartyi-containing culture in continuous stirred-tank reactors (CSTRs) at a short, 3-d HRT, using TCE as the electron acceptor. We successfully operated 3-d HRT CSTRs for up to 120 days and observed sustained dechlorination of TCE at influent concentrations of 1 and 2 mM TCE to ≥ 97 % ethene, coupled to the production of 10(12) D. mccartyi cells Lculture (-1). These outcomes were possible in part by using a medium with low bicarbonate concentrations (5 mM) to minimize the excessive proliferation of microorganisms that use bicarbonate as an electron acceptor and compete with D. mccartyi for H2. The maximum conversion rates for the CSTR-produced culture were 0.13 ± 0.016, 0.06 ± 0.018, and 0.02 ± 0.007 mmol Cl(-) Lculture (-1) h(-1), respectively, for TCE, cis-dichloroethene, and vinyl chloride. The CSTR operation described here provides the fastest laboratory cultivation rate of high-cell density Dehalococcoides cultures reported in the literature to date. This cultivation method provides a fundamental scientific platform for potential future operations of such a system at larger scales.
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Affiliation(s)
- Anca G Delgado
- Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, P.O. Box 875701, Tempe, AZ, 85287-5701, USA,
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Liu X, Yoon S, Batchelor B, Abdel-Wahab A. Degradation of vinyl chloride (VC) by the sulfite/UV advanced reduction process (ARP): effects of process variables and a kinetic model. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 454-455:578-583. [PMID: 23570912 DOI: 10.1016/j.scitotenv.2013.03.060] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/16/2013] [Accepted: 03/16/2013] [Indexed: 06/02/2023]
Abstract
Vinyl chloride (VC) poses a threat to humans and environment due to its toxicity and carcinogenicity. In this study, an advanced reduction process (ARP) that combines sulfite with UV light was developed to destroy VC. The degradation of VC followed pseudo-first-order decay kinetics and the effects of several experimental factors on the degradation rate constant were investigated. The largest rate constant was observed at pH9, but complete dechlorination was obtained at pH11. Higher sulfite dose and light intensity were found to increase the rate constant linearly. The rate constant had a little drop when the initial VC concentration was below 1.5mg/L and then was approximately constant between 1.5mg/L and 3.1mg/L. A degradation mechanism was proposed to describe reactions between VC and the reactive species that were produced by the photolysis of sulfite. A kinetic model that described major reactions in the system was developed and was able to explain the dependence of the rate constant on the experimental factors examined. This study may provide a new treatment technology for the removal of a variety of halogenated contaminants.
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Affiliation(s)
- Xu Liu
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA.
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Heavner GLW, Rowe AR, Mansfeldt CB, Pan JK, Gossett JM, Richardson RE. Molecular biomarker-based biokinetic modeling of a PCE-dechlorinating and methanogenic mixed culture. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:3724-33. [PMID: 23363057 DOI: 10.1021/es303517s] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Bioremediation of chlorinated ethenes via anaerobic reductive dechlorination relies upon the activity of specific microbial populations--most notably Dehalococcoides (DHC) strains. In the lab and field Dehalococcoides grow most robustly in mixed communities which usually contain both fermenters and methanogens. Recently, researchers have been developing quantitative molecular biomarkers to aid in field site diagnostics and it is hoped that these biomarkers could aid in the modeling of anaerobic reductive dechlorination. A comprehensive biokinetic model of a community containing Dehalococcoides mccartyi (formerly D. ethenogenes) was updated to describe continuously fed reactors with specific biomass levels based on quantitative PCR (qPCR)-based population data (DNA and RNA). The model was calibrated and validated with subsets of chemical and molecular biological data from various continuous feed experiments (n = 24) with different loading rates of the electron acceptor (1.5 to 482 μeeq/L-h), types of electron acceptor (PCE, TCE, cis-DCE) and electron donor to electron acceptor ratios. The resulting model predicted the sum of dechlorination products vinyl chloride (VC) and ethene (ETH) well. However, VC alone was under-predicted and ETH was over predicted. Consequently, competitive inhibition among chlorinated ethenes was examined and then added to the model. Additionally, as 16S rRNA gene copy numbers did not provide accurate model fits in all cases, we examined whether an improved fit could be obtained if mRNA levels for key functional enzymes could be used to infer respiration rates. The resulting empirically derived mRNA "adjustment factors" were added to the model for both DHC and the main methanogen in the culture (a Methanosaeta species) to provide a more nuanced prediction of activity. Results of this study suggest that at higher feeding rates competitive inhibition is important and mRNA provides a more accurate indicator of a population's instantaneous activity than 16S rRNA gene copies alone as biomass estimates.
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Affiliation(s)
- Gretchen L W Heavner
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY, USA
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Chambon JC, Bjerg PL, Scheutz C, Baelum J, Jakobsen R, Binning PJ. Review of reactive kinetic models describing reductive dechlorination of chlorinated ethenes in soil and groundwater. Biotechnol Bioeng 2012; 110:1-23. [DOI: 10.1002/bit.24714] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 08/13/2012] [Accepted: 08/16/2012] [Indexed: 11/08/2022]
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