BIOREMEDIATION OF CHLOROPHENOL CONTAMINATED GROUND-WATER

Two aerobic laboratory-scale continuous-flow fluidized-bed reactors we re used to study biological ground water decontamination from chloroph enols. Biomass in both reactors was enriched using synthetic chlorophe nol feed. The chlorophenol degradation was monitored by inorganic chlo ride release (ICI), organic carbon removal and gas chromatographic ana lyses. The chlorophenol concentration in Karkola aquifer, Finland rema ined stable through a two year period. Fluidized-bed treatment of grou nd water contaminated with 44-55 mgl-1 of chlorophenols resulted in le ss than 1 mgl-1 effluent concentrations and corresponding ICl releases . 99% chlorophenol degradation was maintained even at 45 min hydraulic retention time (HRT) and 1500 gCPm-3 d-1 loading rate. During gradual temperature decrease from 25-30-degrees-C to 10-degrees-C within 4 mo nths, ICl release remained stable. At 10-degrees-C, over 99% chlorophe nol removal, and effluent concentrations of less than 0.1 mgl-1, were maintained at 5 h HRT and 240 gCPm-3 d-1 loading rate. Reactors were c ontinuously operated for 11 and 7 months without failures in chlorophe nol degradation performances.