The feasibility of combining the reductive dechlorination and oxidative mineralization of tetrachloroethene (PCE) within one system was investigated in non-shaken methanotrophic batch cultivated cell suspensions. In the presence of up to 90% [v/v] methane and 10% [v/v] oxygen in the headspace, 200, 400 and 500 µmol/l PCE were completely dechlorinated over 100 days of incubation with 1% [v/v] activated sludge derived from a municipal wastewater treatment plant (equivalent to 6 mmol/l carbon). Meanwhile nearly 4 mol/l chloride were released to the medium for each mol PCE dechlorinated, indicating that the volatile chlorinated compound was completely dechlorinated in the cell suspensions. Irrespectively of the initial PCE concentration, 40 µmol/l trichloroethene were found temporarily. According to the initial PCE concentration, up to 160 µmol/l cis-dichloroethene were measured in the assays with 500 µmol/l PCE. In the presence of oxygen in the headspace, simultaneously with the dechlorination, methane was oxidized. At 7% [v/v] methane and 10% [v/v] oxygen, 500 µmol/l PCE were dechlorinated to cDCE within 145 days. At PCE concentrations of 600 µmol/l or above, substrate inhibition occurred, and then both the dechlorination and the oxidation of methane were inhibited.

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