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The co-existence of volatile chlorinated hydrocarbons (VCHs) and nitrate pollution in groundwater is prominent, but how nitrate exposure affects weak-electrical stimulated bio-dechlorination activity of VCH is largely unknown. Here, by establishing weak-electrical stimulated trichloroethylene (TCE) dechlorination systems, the influence on TCE dechlorination by exposure to the different concentrations (25-100 mg L) of nitrate was investigated. The existence of nitrate in general decreased TCE dechlorination efficiency to varying degrees, and the higher nitrate concentration, the stronger the inhibitory effects, verified by the gradually decreased transcription levels of tceA. Although the TCE dechlorination kinetic rate constant decreased by 36% the most, under all nitrate concentration ranges, TCE could be completely removed within 32 h and no difference in generated metabolites was found, revealing the well-maintained dechlorination activity. This was due to the quickly enriched bio-denitrification activity, which removed nitrate completely within 9 h, and thus relieved the inhibition on TCE dechlorination. The obvious bacterial community structure succession was also observed, from dominating with dechlorination genera (e.g., Acetobacterium, Eubacterium) to dominating with both dechlorination and denitrification genera (e.g., Acidovorax and Brachymonas). The study proposed the great potential for the in situ simultaneous denitrification and dehalogenation in groundwater contaminated with both nitrate and VCHs.
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http://dx.doi.org/10.1016/j.chemosphere.2022.133935 | DOI Listing |
Toxics
July 2025
Battelle Memorial Institute, 505 King Ave, Columbus, OH 43201, USA.
Microplastics (MPs) and nanoplastics (NPs) can affect microbial abundance and activity, likely by damaging cell membrane components. While their effects on anaerobic digestion are known, less is understood about their impact on microbes involved in contaminant bioremediation. Chlorinated volatile organic contaminants (CVOCs) such as tetrachloroethene (PCE) and explosives like hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) are common in the environment, and their bioremediation is a promising cleanup strategy.
View Article and Find Full Text PDFJ Hazard Mater
September 2025
Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Soil Pollution Control and Safety, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang
Atomic hydrogen (*H) in bimetallic nanoscale zero-valent iron (M-nFe)-water system plays a dominant role for realizing in-situ deep dechlorination reactions, yet its selective generation and sustainable utilization remain challenging. Herein, a structural modulation strategy was proposed to design lattice engineered M-nFe (M-nFe), which generated controllable lattice strain and strong M-Fe chemical bonds, thus steering *H generation/accumulation and achieving deep dechlorination of various organic pollutants. Compared with traditional surface nickel-modified nFe (Ni-Fe), the dechlorination rate of Ni-Fe for TCE and 4-CP was improved by 3.
View Article and Find Full Text PDFJ Hazard Mater
September 2025
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address:
A series of thermally enhanced biodegradation (TEB) experiments at varying temperatures (15, 30 and 45 °C) were conducted to evaluate their effects on the biodegradation kinetics of trichloroethene (TCE) and benzene co-mingled contaminants using indigenous microbial consortiums. Results demonstrated that the highest TCE biodegradation rate, 0.35 μmol L⁻¹ day⁻¹ , with a half-life of 49 days, was observed at 30 °C, whereas the biodegradation of benzene was enhanced to a less extent.
View Article and Find Full Text PDFWater Res
October 2025
Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing 210095, China. Electronic address:
Trichloroethene (TCE) and toluene are ubiquitous co-contaminants in groundwater and soil, yet effective strategies for their concurrent remediation remain challenging due to inhibitory interactions and substrate competitions. In this study, we obtained two anaerobic enrichment cultures capable of detoxifying TCE and toluene with degradation rates of 141.7 ± 57.
View Article and Find Full Text PDFJ Hazard Mater
September 2025
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address:
The co-mingled plumes of chloroethenes and per- and polyfluoroalkyl substances (PFASs) raise a major challenge for groundwater remediation. This study is the first try to apply sulfidated nano zero-valent iron supported on calcined layered double oxides (S-nZVI@LDO) for simultaneous removal of trichloroethylene (TCE) and perfluorooctanoic acid (PFOA). Our findings revealed that 2 g/L S-nZVI@LDO simultaneously removed 73.
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