Abstract
Tetrachloroethylene (PCE), a prevalent groundwater contaminant, can be completely dechlorinated to ethylene (ETY) and ethane (ETA) under anaerobic conditions in the presence of a suitable electron donor. ETY and ETA are harmless and environmentally acceptable products.
This study was conducted to examine the feasibility of using an anaerobic filter for the treatment of PCE in bioremediation process. A laboratory-scale continuously-fed upflow anaerobic filter was operated at hydraulic retention times (HRTs) of 4.0-1.0 days in a 25°C constant room. Influent PCE concentration was 2.8mg·l-1 and ethanol (100mg COD·l-1) was dosed as an electron donor. Anaerobic PCE-dechlorinating enrichment culture was used as inoculum. Immediately after the start-up, the system showed an excellent capability in dechlorinating PCE to trichloroethylene (TCE), dichloroethylene, vinyl chloride, ETY and ETA. PCE and TCE were never detected (less than 0.005mg·l-1) in the effluent and the conversion efficiency of PCE to ETY and ETA was above 97% at HRTs of 2.0-1.0 days. Moreover, effluent COD concentration was low (20-25mg·l-1). Results of this study suggest that the anaerobic filter system is a feasible bioremediation process for the treatment of chlorinated ethylenes.
