TREATMENT OF CHLORDANE-CONTAMINATED WATER BY THE ACTIVATED ROTATING BIOLOGICAL CONTACTOR

The insecticide chlordane (1,2,4,5,6,7,8,8-octachloro-2, 3,3a,4,7,7a-hexahydro-4,7-methanoindene) has been detected as a contaminant in groundwaters and surface waters. This study investigated the removal characteristics of chlordane using the activated rotating biological contactor (ARBC). Chlordane concentrations ranged from 0.1 to 4.6 mg/L with organic supplement levels of 500 and 175 mg/L of BOD5. The chlordane removal efficiencies ranged from 75 to 96% and the organic removal efficiencies (BOD5) ranged from 95 to 99%. Shock loadings of chlordane did not significantly hinder chlordane or organic removal efficiencies. Mass balances of the chlordane throughout the study showed 58 to 89% of the influent chlordane was not accounted for in the effluent, the system or waste solids. The relatively low volatility of chlordane and the low adsorption of the chlordane to the biomass indicates biological transformation as the primary removal mechanism in this study.