title: Bio-beads with immobilized anaerobic bacteria, zero-valent iron, and active carbon for the removal of trichloroethane from groundwater.
abstract: Chlorinated hydrocarbons are the most common organic pollutants in groundwater systems worldwide. In this study, we developed bio-beads with immobilized anaerobic bacteria, zero-valent iron (ZVI), and activated carbon (AC) powder and evaluated their efficacy in removing 1,1,1-trichloroethane (TCA) from groundwater. Bio-beads were produced by polyvinyl alcohol, alginate, and AC powder. We found that the concentration of AC powder used significantly affected the mechanical properties of immobilized bio-beads and that 1.0 % (w/v) was the optimal concentration. The bio-beads effectively degraded TCA (160 mg L(-1)) in the anaerobic medium and could be reused up to six times. The TCA degradation rate of bio-beads was 1.5 and 2.3 times greater, respectively, than ZVI + AC treatment or microbes + AC treatment. Measuring FeS produced by microbial reactions indicated that TCA removal occurred via FeS-catalyzed dechlorination. Analysis of clonal libraries derived from bio-beads demonstrated that the dominant species in the community were Betaproteobacteria and Gammaproteobacteria, which may contribute to the long-term stability of ZVI reactivity during TCA dechlorination. This study shows that the combined use of immobilized anaerobic bacteria, ZVI, and AC in bio-beads is effective and practical for TCA dechlorination and suggests they may be applicable towards developing a groundwater treatment system for the removal of TCA.
authors.affiliation: State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, State Key Laboratory of Bioreactor Engineering, School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China.
authors.forename: Ya-Zhen
authors.initials: YZ
authors.lastname: Zhou
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wang
authors.forename: Yue-Qing
authors.initials: YQ
authors.lastname: Pan
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Dong
authors.initials: D
authors.lastname: Zhou
authors.forename: Yong-Di
authors.initials: YD
authors.lastname: Liu
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Ji-Dong
authors.initials: JD
authors.lastname: Gu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lu
authors.forename: Yue-Feng
authors.initials: YF
authors.lastname: Qiu
authors.forename: Kuang-Fei
authors.initials: KF
authors.lastname: Lin
mesh_terms: D001421:Bacteria, Anaerobic / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002244:Carbon / Q000737:chemistry*; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005296:Ferrous Compounds / Q000378:metabolism; D060587:Groundwater / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008969:Molecular Sequence Data; D014240:Trichloroethanes / Q000737:chemistry / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism; D018508:Water Purification / Q000379:methods
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005296:Ferrous Compounds; D014240:Trichloroethanes; D014874:Water Pollutants, Chemical; C024566:1,1,1-trichloroethane; D002244:Carbon; D007501:Iron; C022597:ferrous sulfide