title: Treatment of co-mingled benzene, toluene and TCE in groundwater.
abstract: This work addressed a hypothetical but practical scenario that includes biological oxidation and reductive dechlorination in treating groundwater containing co-mingled plume of trichloroethene (TCE), benzene and toluene. Groundwater immediately downgradient from the commonly used zero-valent iron (ZVI) has shown alkaline pH (up to 10.7). The elevated pH may influence BTEX compounds (i.e., benzene, toluene, ethyl benzene, and xylenes) biodegradation, which could also be inhibited by elevated concentrations of TCE. Data from this work suggests that the inhibition coefficients (IC) value for 100 μg/L and 500 μg/L of TCE on benzene and toluene degradation are 2.1-2.8 at pH 7.9, and 3.5-6.1 at pH 10.5. For a co-mingled plume, it appears to be more effective to reduce TCE by ZVI before addressing benzene and toluene biodegradation. The ample buffering capacity of most groundwater and the adaptation of benzene and toluene-degrading microbes are likely able to eliminate the adverse influence of pH shifts downgradient from a ZVI-PRB.
authors.affiliation: State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, PR China; Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083, PR China.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Research Institute of Safety and Environment Technology, China National Petroleum Corporation, Beijing 102206, PR China.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing 100083, PR China.
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Civil and Architectural Engineering, University of Wyoming, Laramie, WY 82071, USA; Advanced Environmental Technologies LLC., Fort Collins, CO 80525, USA. Electronic address: sjin@uwyo.edu.
authors.forename: Song
authors.initials: S
authors.lastname: Jin
mesh_terms: D001554:Benzene / Q000378:metabolism*; D001673:Biodegradation, Environmental; D060587:Groundwater; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D014050:Toluene / Q000378:metabolism*; D014241:Trichloroethylene / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D014241:Trichloroethylene; D014050:Toluene; D001554:Benzene
keywords: BTEX; Co-mingled contamination; TCE; Toluene; Trichloroethene; pH and ZVI