title: Enhanced degradation of chlorinated ethylenes in groundwater from a paint contaminated site by two-stage fluidized-bed reactor.
abstract: Groundwater, used in this study, contaminated predominantly with aromatic compounds, was biologically treated in a fluidized-bed reactor (FBR) with immobilized cells. The aromatics were completely decomposed, while cis-1,2-dichloroethylene (cis-DCE) and trichloroethylene (TCE) were decomposed only approximately 20% and 5%, respectively. In these studies a significant improvement of the decomposition efficiency for chlorinated ethylenes was achieved by utilizing cometabolism. Methanol (MeOH) and toluene were used as the substrate in the case of one-stage reactor (Single Reactor). MeOH (187 mg l(-1)) increased the decomposition efficiency up to 40% and 60% for cis-DCE and TCE, respectively, while toluene (20 mg l(-1)) increased the decomposition efficiency of cis-DCE to 92% and the decomposition efficiency of TCE to 76%. In the case of two-stage reactor system (Reactor 1 and Reactor 2), MeOH and methane (CH4) were used as the substrate. In this system, cells grown on MeOH or CH4 in the Reactor 1 were continuously fed into Reactor 2 and groundwater was fed into Reactor 2 only. When MeOH (384 mg l(-1) d(-1)) was used as substrate the decomposition efficiency of cis-DCE and TCE were 60% and 70%, respectively. Similar decomposition efficiency was observed for a small amount of CH4 (19.3 mg l(-1) d(-1)).
authors.affiliation: Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
authors.forename: K
authors.initials: K
authors.lastname: Ohlen
authors.forename: Y K
authors.initials: YK
authors.lastname: Chang
authors.forename: W
authors.initials: W
authors.lastname: Hegemann
authors.forename: C-R
authors.initials: CR
authors.lastname: Yin
authors.forename: S-T
authors.initials: ST
authors.lastname: Lee
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D004000:Dichloroethylenes / Q000378:metabolism*; D010150:Paint; D012989:Soil Pollutants / Q000378:metabolism; D012997:Solvents / Q000378:metabolism*; D014241:Trichloroethylene / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D004000:Dichloroethylenes; D012989:Soil Pollutants; D012997:Solvents; D014874:Water Pollutants, Chemical; D014241:Trichloroethylene; C035384:1,2-dichloroethylene