BIODEGRADATION OF TETRACHLOROMETHANE UNDER ANAEROBIC CONDITIONS

An anaerobic upflow fixed film reactor of one meter height and 8 cm inside diameter was used to investigate biodegradation of tetrachloromethane (CT). With an empty bed retention time of 20 h, CT in concentration of about 2.7 mg/l was completely eliminated within the first half of the filter when a mixture of different primary substrates was provided. Concentrations of chlorinated compounds at different heights of the filter were measured. With decreasing concentrations of CT increasing concentrations of trichloromethane (CF) were observed which remained unchanged when CT was eliminated. Effluent concentrations of CF were about 20 ... 25% of the influent CT concentrations on a molar basis. When primary substrates were changed to acetate as the only additional carbon source, degradation of CT was drastically deteriorated, indicating that acetate degrading cultures are not responsible for degradation of CT.