The Experts below are selected from a list of 26604 Experts worldwide ranked by ideXlab platform
Steven F Thornton - One of the best experts on this subject based on the ideXlab platform.
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biodegradation of phenolic compounds and their metabolites in Contaminated Groundwater using microbial fuel cells
Bioresource Technology, 2016Co-Authors: Petra Hedbavna, Stephen A Rolfe, Wei E Huang, Steven F ThorntonAbstract:This is the first study demonstrating the biodegradation of phenolic compounds and their organic metabolites in Contaminated Groundwater using bioelectrochemical systems (BESs). The phenols were biodegraded anaerobically via 4-hydroxybenzoic acid and 4-hydroxy-3-methylbenzoic acid, which were retained by electromigration in the anode chamber. Oxygen, nitrate, iron(III), sulfate and the electrode were electron acceptors for biodegradation. Electro-active bacteria attached to the anode, producing electricity (~1.8mW/m(2)), while utilizing acetate as an electron donor. Electricity generation started concurrently with iron reduction; the anode was an electron acceptor as thermodynamically favorable as iron(III). Acetate removal was enhanced by 40% in the presence of the anode. However, enhanced removal of phenols occurred only for a short time. Field-scale application of BESs for in situ bioremediation requires an understanding of the regulation and kinetics of biodegradation pathways of the parent compounds to relevant metabolites, and the syntrophic interactions and carbon flow in the microbial community.
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effect of contaminant concentration on in situ bacterial sulfate reduction and methanogenesis in phenol Contaminated Groundwater
Applied Geochemistry, 2012Co-Authors: Kieran M Baker, Kate E Peel, Steven F Thornton, Simon H Bottrell, Michael SpenceAbstract:Abstract The availability of dissolved O2 can limit biodegradation of organic compounds in aquifers. Where O2 is depleted, biodegradation proceeds via anaerobic processes, including NO3-, Mn(IV)-, Fe(III)- and SO4-reduction and fermentation/methanogenesis. The environmental controls on these anaerobic processes must be understood to support implementation of management strategies such as monitored natural attenuation (MNA). In this study stable isotope analysis is used to show that the relative significance of two key anaerobic biodegradation processes (bacterial SO4 reduction (BSR) and methanogenesis) in a phenol-Contaminated sandstone aquifer is sensitive to spatial and temporal changes in total dissolved phenols concentration (TPC) (= phenol + cresols + dimethylphenols) over a 5-a period. In general, 34SO4-enrichment (characteristic of bacterial SO4 reduction) is restricted spatially to locations where TPC 500 mg L−1, and suggests that methanogenic microorganisms may have a higher tolerance for TPC in this contaminant plume. It is concluded that isotopic enrichment trends can be used to identify conditions under which in situ biodegradation may be limited by the properties of the biodegradation substrate (in this case TPC). Such data may be used to deduce the performance of MNA for Contaminated Groundwater in similar settings.
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effect of contaminant concentration on in situ bacterial sulfate reduction and methanogenesis in phenol Contaminated Groundwater
Applied Geochemistry, 2012Co-Authors: Kieran M Baker, Steven F Thornton, Simon H Bottrell, Kate Peel, Michael SpenceAbstract:Abstract The availability of dissolved O 2 can limit biodegradation of organic compounds in aquifers. Where O 2 is depleted, biodegradation proceeds via anaerobic processes, including NO 3 -, Mn(IV)-, Fe(III)- and SO 4 -reduction and fermentation/methanogenesis. The environmental controls on these anaerobic processes must be understood to support implementation of management strategies such as monitored natural attenuation (MNA). In this study stable isotope analysis is used to show that the relative significance of two key anaerobic biodegradation processes (bacterial SO 4 reduction (BSR) and methanogenesis) in a phenol-Contaminated sandstone aquifer is sensitive to spatial and temporal changes in total dissolved phenols concentration (TPC) (= phenol + cresols + dimethylphenols) over a 5-a period. In general, 34 SO 4 -enrichment (characteristic of bacterial SO 4 reduction) is restricted spatially to locations where TPC −1 . In contrast, 13 C-depleted CH 4 and 13 C-enriched CO 2 isotope compositions (characteristic of methanogenesis) were measured at TPC up to 8000 mg L −1 . This is consistent with previous studies that demonstrate suppression of BSR at TPC of >500 mg L −1 , and suggests that methanogenic microorganisms may have a higher tolerance for TPC in this contaminant plume. It is concluded that isotopic enrichment trends can be used to identify conditions under which in situ biodegradation may be limited by the properties of the biodegradation substrate (in this case TPC). Such data may be used to deduce the performance of MNA for Contaminated Groundwater in similar settings.
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improved analysis of mtbe tame and tba in petroleum fuel Contaminated Groundwater by spme using deuterated internal standards with gc ms
Environmental Science & Technology, 2003Co-Authors: Paul Dewsbury, Steven F Thornton, David N LernerAbstract:An improved method is described for the routine analysis of methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), and tert-butyl alcohol (TBA) in petroleum fuel-Contaminated Groundwater samples using solid-phase microextraction (SPME) and deuterated internal standards combined with gas chromatography mass spectrometry (GC-MS). Factors affecting method performance (SPME fiber selection, headspace or liquid extraction, extraction time, calibration conditions, salt addition, method sensitivity, and matrix effects) are evaluated using Groundwater samples from a chalk aquifer Contaminated with petroleum fuel containing MTBE, TAME, and TBA. The detection sensitivity and analytical efficiency of the method was optimized for these compounds using a PDMS-Carboxen fiber, sample NaCl content of 25% (w/v), and extraction time of 30 min. Internal calibration standards (deuterated MTBE and TBA) are necessary to control extraction errors during analysis. SPME extraction efficiency and detection sensitivity for ...
Robert M. Kalin - One of the best experts on this subject based on the ideXlab platform.
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performance of a field scale biological permeable reactive barrier for in situ remediation of nitrate Contaminated Groundwater
Science of The Total Environment, 2019Co-Authors: Oriol Gibert, Amer Assal, Trevor Elliot, Hayley Devlin, Robert M. KalinAbstract:We report the performance of a field-scale permeable reactive barrier (PRB) for the biological treatment of nitrate-Contaminated Groundwater. The reactive material of the PRB consisted of a mixture of gravel and mulch as a carbon source for denitrifying bacteria. The PRB was equipped with a delivery system that allowed injecting NO3- at controlled rates from the surface directly into the up-gradient layer of the PRB. This way, NO3- concentration entering the PRB was varied (from 1 to 530 mg/L) with the purpose of evaluating the ultimate efficiency of the PRB under different NO3- loadings. The PRB was successful at removing NO3- from Groundwater at inlet concentrations up to 280 mg/L (with NO3- removal percentages ≥97%). Monitoring of Groundwater at different depths within the PRB provided evidence that NO3- underwent denitrification preferably at the deepest part of the PRB, where more favourable reducing conditions were achieved. Among the shortcomings of the PRB were the fluctuations of Groundwater fluxes caused by intense rainfalls during the study period, although they generally did not pose concern for the denitrification capacity of the PRB. Emission fluxes of gases (CO2, CH4 and N2O) from the PRB to the atmosphere were also measured. The results are finally compared with the few others reported existing PRBs for nitrate-Contaminated Groundwater worldwide.
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ten year performance evaluation of a field scale zero valent iron permeable reactive barrier installed to remediate trichloroethene Contaminated Groundwater
Environmental Science & Technology, 2010Co-Authors: Debra Phillips, Thomas Van Nooten, Keith Dickson, S Plant, Jason M E Ahad, T Newton, Trevor Elliot, M I Russell, Leen Bastiaens, Robert M. KalinAbstract:The Monkstown zero-valent iron permeable reactive barrier (ZVI PRB), Europe’s oldest commercially-installed ZVI PRB, had been treating trichloroethene (TCE) Contaminated Groundwater for about 10 years on the Nortel Network site in Northern Ireland when cores from the reactive zone were collected in December, 2006. Groundwater data from 2001−2006 indicated that TCE is still being remediated to below detection limits as the Contaminated Groundwater flows through the PRB. Ca and Fe carbonates, crystalline and amorphous Fe sulfides, and Fe (hydr)oxides have precipitated in the granular ZVI material in the PRB. The greatest variety of minerals is associated with a ∼1-2 cm thick, slightly cemented crust on top (up-gradient influent entrance) of the ZVI section of the PRB and also with the discontinuous cemented ZVI material (∼23 cm thick) directly below it. The greatest presence of microbial communities also occurred in the up-gradient influent portion of the PRB compared to its down-gradient effluent section, ...
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ten year performance evaluation of a field scale zero valent iron permeable reactive barrier installed to remediate trichloroethene Contaminated Groundwater
Environmental Science & Technology, 2010Co-Authors: Debra Phillips, Keith Dickson, S Plant, Jason M E Ahad, T Newton, Trevor Elliot, M I Russell, Leen Bastiaens, T Van Nooten, Robert M. KalinAbstract:The Monkstown zero-valent iron permeable reactive barrier (ZVI PRB), Europe's oldest commercially-installed ZVI PRB, had been treating trichloroethene (TCE) Contaminated Groundwater for about 10 years on the Nortel Network site in Northern Ireland when cores from the reactive zone were collected in December, 2006. Groundwater data from 2001-2006 indicated that TCE is still being remediated to below detection limits as the Contaminated Groundwater flows through the PRB. Ca and Fe carbonates, crystalline and amorphous Fe sulfides, and Fe (hydr)oxides have precipitated in the granular ZVI material in the PRB. The greatest variety of minerals is associated with a approximately 1-2 cm thick, slightly cemented crust on top (up-gradient influent entrance) of the ZVI section of the PRB and also with the discontinuous cemented ZVI material ( approximately 23 cm thick) directly below it. The greatest presence of microbial communities also occurred in the up-gradient influent portion of the PRB compared to its down-gradient effluent section, with the latter possibly due to less favorable conditions (i.e., high pH, low oxygen) for microbial growth. The ZVI filings in the down-gradient effluent section of the PRB have a projected life span of >10 years compared with ZVI filings from the continuous to discontinuous cemented up-gradient ZVI section (upper approximately 25 cm) of the PRB, which may have a life span of only approximately 2-5 more years. Supporting Information from applied, multi-tracer testing indicated that restricted Groundwater flow is occurring in the upper approximately 25 cm of the ZVI section and preferential pathways have also formed in this PRB over its 10 years of operation.
Edward J Zillioux - One of the best experts on this subject based on the ideXlab platform.
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phytoremediation of arsenic Contaminated Groundwater using arsenic hyperaccumulator pteris vittata l effects of frond harvesting regimes and arsenic levels in refill water
Journal of Hazardous Materials, 2011Co-Authors: Seenivasan Natarajan, Lena Q, Robert H Stamps, Uttam Saha, Damaris Hernandez, Yong Cai, Edward J ZilliouxAbstract:A large-scale hydroponic system to phytoremediate arsenic-Contaminated Groundwater using Pteris vittata (Chinese brake fern) was successfully tested in a field. In this 30-wk study, three frond-harvesting regimes (all, mature, and senescing fronds) and two water-refilling schemes to compensate for evapotranspiration (high-As water of 140-180 μg/L and low-As water of <7 μg/L) were investigated. Two experiments (Cycle 1 and Cycle 2) were conducted using the same plants in 24 tanks with each containing 600 L of arsenic-Contaminated Groundwater and 32 ferns. During Cycle 1 and with initial As of 140 μg/L, As in tanks refilled with low-As water was reduced to <10 μg/L in 8 wks compared to <10 μg/L in 17 wks in tanks refilled with high-As water. During Cycle 2 and with initial As of 180 μg/L, the remediation time was reduced by 2-5 wks, indicating that more established ferns were more efficient. In areas where clean water is limiting, refilling high-As water coupled with harvesting senescing fronds is recommended for more effective As phytoremediation.
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phytoremediation of arsenic Contaminated Groundwater by the arsenic hyperaccumulating fern pteris vittata l
International Journal of Phytoremediation, 2004Co-Authors: S Tu, Abioye O Fayiga, Lena Q, Edward J ZilliouxAbstract:ABSTRACT Arsenic concentrations in a much larger fraction of U.S. Groundwater sources will exceed the maximum contaminant limit when the new 10 μg L−1 EPA standard for drinking water takes effect in 2006. Thus, it is important to develop remediation technologies that can meet this new standard. Phytoremediation of arsenic-Contaminated Groundwater is a relatively new idea. In this research, an arsenic-hyperaccumulating fern, commonly known as Chinese Brake fern (Pteris vittata L.), was grown hydroponically to examine its effectiveness in arsenic removal from what is believed to be herbicide-Contaminated Groundwater. One plant grown in 600 mL of Groundwater effectively reduced the arsenic concentration from 46 to less than 10 μg L−1 in 3 days. Re-used plants continued to take up arsenic from the Groundwater, albeit at a slower rate (from 46 to 20 μg L− 1 during the same time). Young fern plants were more efficient in removing arsenic than were older fern plants of similar size. The addition of a supplement ...
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phytoremediation of arsenic Contaminated Groundwater by the arsenic hyperaccumulating fern pteris vittata l
International Journal of Phytoremediation, 2004Co-Authors: Lena Q, Abioye O Fayiga, Edward J ZilliouxAbstract:Arsenic concentrations in a much larger fraction of U.S. Groundwater sources will exceed the maximum contaminant limit when the new 10 microg L(-1) EPA standard for drinking water takes effect in 2006. Thus, it is important to develop remediation technologies that can meet this new standard. Phytoremediation of arsenic-Contaminated Groundwater is a relatively new idea. In this research, an arsenic-hyperaccumulating fern, commonly known as Chinese Brake fern (Pteris vittata L.), was grown hydroponically to examine its effectiveness in arsenic removal from what is believed to be herbicide-Contaminated Groundwater. One plant grown in 600 mL of Groundwater effectively reduced the arsenic concentration from 46 to less than 10 microg L(-1) in 3 days. Re-used plants continued to take up arsenic from the Groundwater, albeit at a slower rate (from 46 to 20 microg L(-1) during the same time). Young fern plants were more efficient in removing arsenic than were older fern plants of similar size. The addition of a supplement of phosphate-free Hoagland nutrition to the Groundwater had little effect on arsenic removal, but the addition of phosphate nutrition significantly reduced its arsenic affinity and, thus, inhibited the arsenic removal. This study suggested that Chinese Brake has some potential to remove arsenic from Groundwater.
Michael Spence - One of the best experts on this subject based on the ideXlab platform.
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effect of contaminant concentration on in situ bacterial sulfate reduction and methanogenesis in phenol Contaminated Groundwater
Applied Geochemistry, 2012Co-Authors: Kieran M Baker, Kate E Peel, Steven F Thornton, Simon H Bottrell, Michael SpenceAbstract:Abstract The availability of dissolved O2 can limit biodegradation of organic compounds in aquifers. Where O2 is depleted, biodegradation proceeds via anaerobic processes, including NO3-, Mn(IV)-, Fe(III)- and SO4-reduction and fermentation/methanogenesis. The environmental controls on these anaerobic processes must be understood to support implementation of management strategies such as monitored natural attenuation (MNA). In this study stable isotope analysis is used to show that the relative significance of two key anaerobic biodegradation processes (bacterial SO4 reduction (BSR) and methanogenesis) in a phenol-Contaminated sandstone aquifer is sensitive to spatial and temporal changes in total dissolved phenols concentration (TPC) (= phenol + cresols + dimethylphenols) over a 5-a period. In general, 34SO4-enrichment (characteristic of bacterial SO4 reduction) is restricted spatially to locations where TPC 500 mg L−1, and suggests that methanogenic microorganisms may have a higher tolerance for TPC in this contaminant plume. It is concluded that isotopic enrichment trends can be used to identify conditions under which in situ biodegradation may be limited by the properties of the biodegradation substrate (in this case TPC). Such data may be used to deduce the performance of MNA for Contaminated Groundwater in similar settings.
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effect of contaminant concentration on in situ bacterial sulfate reduction and methanogenesis in phenol Contaminated Groundwater
Applied Geochemistry, 2012Co-Authors: Kieran M Baker, Steven F Thornton, Simon H Bottrell, Kate Peel, Michael SpenceAbstract:Abstract The availability of dissolved O 2 can limit biodegradation of organic compounds in aquifers. Where O 2 is depleted, biodegradation proceeds via anaerobic processes, including NO 3 -, Mn(IV)-, Fe(III)- and SO 4 -reduction and fermentation/methanogenesis. The environmental controls on these anaerobic processes must be understood to support implementation of management strategies such as monitored natural attenuation (MNA). In this study stable isotope analysis is used to show that the relative significance of two key anaerobic biodegradation processes (bacterial SO 4 reduction (BSR) and methanogenesis) in a phenol-Contaminated sandstone aquifer is sensitive to spatial and temporal changes in total dissolved phenols concentration (TPC) (= phenol + cresols + dimethylphenols) over a 5-a period. In general, 34 SO 4 -enrichment (characteristic of bacterial SO 4 reduction) is restricted spatially to locations where TPC −1 . In contrast, 13 C-depleted CH 4 and 13 C-enriched CO 2 isotope compositions (characteristic of methanogenesis) were measured at TPC up to 8000 mg L −1 . This is consistent with previous studies that demonstrate suppression of BSR at TPC of >500 mg L −1 , and suggests that methanogenic microorganisms may have a higher tolerance for TPC in this contaminant plume. It is concluded that isotopic enrichment trends can be used to identify conditions under which in situ biodegradation may be limited by the properties of the biodegradation substrate (in this case TPC). Such data may be used to deduce the performance of MNA for Contaminated Groundwater in similar settings.
Nousheen Firdous - One of the best experts on this subject based on the ideXlab platform.
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toxic fluoride and arsenic Contaminated Groundwater in the lahore and kasur districts punjab pakistan and possible contaminant sources
Environmental Pollution, 2007Co-Authors: Abida Farooqi, Harue Masuda, Nousheen FirdousAbstract:Abstract The present study is the first attempt to put forward possible sources of As, F − and SO 4 2− Contaminated Groundwater in the Kalalanwala area, Punjab, Pakistan. Five rainwater and 24 Groundwater samples from three different depths were analyzed. Shallow Groundwater from 24 to 27 m depth contained high F − (2.47–21.1 mg/L), while the Groundwater samples from the deeper depth were free from fluoride contamination. All Groundwater samples contained high As (32–1900 μg/L), in excess of WHO drinking water standards. The SO 4 2− ranges from 110 to 1550 mg/L. δ 34 S data indicate three sources for SO 4 2− air pollutants (5.5–5.7‰), fertilizers (4.8‰), and household waste (7.0‰). Our important finding is the presence of SO 4 2− , As and F − in rainwater, indicating the contribution of these elements from air pollution. We propose that pollutants originate, in part, from coal combusted at brick factories and were mobilized promotionally by the alkaline nature of the local Groundwater.
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toxic fluoride and arsenic Contaminated Groundwater in the lahore and kasur districts punjab pakistan and possible contaminant sources
Environmental Pollution, 2007Co-Authors: Abida Farooqi, Harue Masuda, Nousheen FirdousAbstract:The present study is the first attempt to put forward possible sources of As, F- and SO4(2-) Contaminated Groundwater in the Kalalanwala area, Punjab, Pakistan. Five rainwater and 24 Groundwater samples from three different depths were analyzed. Shallow Groundwater from 24 to 27 m depth contained high F- (2.47-21.1mg/L), while the Groundwater samples from the deeper depth were free from fluoride contamination. All Groundwater samples contained high As (32-1900 microg/L), in excess of WHO drinking water standards. The SO4(2-) ranges from 110 to 1550 mg/L. Delta34S data indicate three sources for SO4(2-) air pollutants (5.5-5.7 per thousand), fertilizers (4.8 per thousand), and household waste (7.0 per thousand). Our important finding is the presence of SO4(2-), As and F- in rainwater, indicating the contribution of these elements from air pollution. We propose that pollutants originate, in part, from coal combusted at brick factories and were mobilized promotionally by the alkaline nature of the local Groundwater.