This study investigated the feasibility of using a polarized graphite electrode as direct or indirect (via electrolytic oxygen generation) electron acceptor to stimulate the microbial oxidation of cis-dichloroethene (cis-DCE) in contaminated groundwater. A microbial culture was enriched in the anode chamber of a bioelectrochemical cell using a mixture of cis-DCE and ethene as substrates. The bioelectrochemical cell was operated by controlling the anode potential at +1.0 V or +1.5 V versus the standard hydrogen electrode (SHE). Enhanced cometabolic removal of cis-DCE, with ethene serving as the growth substrate, was observed in batch tests with the anode polarized at +1.5 V versus SHE. At this potential, (chloro)ethenes removal was probably sustained by molecular oxygen generated at the anode from water oxidation. Conversely, negligible anaerobic degradation was observed at +1.0 V versus SHE (a potential which does not allow oxygen generation), hence suggesting that molecular oxygen is needed to initiate (chloro)ethene degradation. PCR-DGGE analysis of the microbial culture followed by band sequencing and phylogenetic analysis evidenced the selective enrichment of a Bacillus species, providing a strong indication that this microorganism was responsible for cis-DCE and ethene degradation.
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http://dx.doi.org/10.1016/j.nbt.2013.04.003 | DOI Listing |
Environ Sci Technol
November 2024
Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, Netherlands.
Biomarkers such as functional gene mRNA (transcripts) and proteins (enzymes) provide direct proof of metabolic regulation during the reductive dechlorination (RD) of chlorinated ethenes (CEs). Yet, current models to simulate their spatiotemporal variability are not flexible enough to mimic the homologous behavior of functional genes. To this end, we developed new enzyme-based kinetics to model the concentrations of CEs together with the transcript and enzyme levels during RD.
View Article and Find Full Text PDFSci Total Environ
November 2024
Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Hidrogeologia (MAGH), Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Institut de Recerca de l'Aigua (IdRA), Universitat de Barcelona (UB), Martí Franquès s/n, 08028 Barcelona, Spain.
Enhanced In Situ Bioremediation (EISB) using Emulsified Vegetable Oil (EVO) as a long-term electron donor has gained prominence for the treatment of groundwater contaminated with chlorinated ethenes (CEs). This study explores the potential of isotopic and molecular biology tools (MBT) to investigate the CEs (PCE, TCE and cis-DCE) bioremediation using EVO in a contaminated site. A multiple approach using C and Cl-CSIA, quantification of Dehalococcoides (Dhc) and specific reductive dechlorination (RD) gene population, and hydrochemical data in microcosm experiments and field samples was applied.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
March 2024
University of Natural Resources and Life Sciences, Vienna, Department of Forest- and Soil Sciences, Institute of Soil Research, Peter-Jordan-Straße 82, 1190 Vienna, Austria.
Sulfidated nano- and microscale zero-valent iron (S-(n)ZVI) has shown enhanced selectivity and reactive lifetime in the degradation of chlorinated ethenes (CEs) compared to pristine (n)ZVI. However, varying effects of sulfidation on the dechlorination rates of structurally similar CEs have been reported, with the underlying mechanisms remaining poorly understood. In this study, we investigated the -dichloroelimination reactions of tetrachloroethene (PCE), trichloroethene (TCE), -1,2-dichloroethene (-DCE), and -1,2-dichloroethene (-DCE) at the S and Fe sites of several S-(n)ZVI surface models by using density functional theory.
View Article and Find Full Text PDFEnviron Sci Technol
June 2023
Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York 14853, United States.
Perfluoroalkyl acids (PFAAs) have been shown to inhibit biodegradation (i.e., organohalide respiration) of chlorinated ethenes.
View Article and Find Full Text PDFJ Hazard Mater
March 2023
Institute of Environmental Processes and Pollution control, and School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China.
Ball milling is an effective technique to not only activate and reduce the size of commercial microscale zero valent iron (mZVI) but also to mechanochemically sulfidate mZVI. Yet, little is known about the difference between how chlorinated ethenes (CEs) interact with ball milled mZVI (mZVI) and mechanochemically sulfidated mZVI (S-mZVI). We show that simple ball milling exposed the active Fe sites, while mechanochemical sulfidation diminished Fe sites and meanwhile increased S sites.
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