COMETABOLIC DEGRADATION OF TCE AND DCE WITHOUT INTERMEDIATE TOXICITY

Trichloroethylene (TCE) and cis-1,2-dichloroethylene (DCE) cometabolic degradation by a filamentous, phenol-oxidizing enrichment from a surf ace-water source were investigated in batch tests. No intermediate tox icity effects were evident during TCE or DCE degradation for loadings up to 0.5 mg TCE/mg VSS or 0.26 mg DCE/mg VSS. Phenol addition up to 4 0 mg/L did not inhibit TCE or DCE degradation. TCE specific degradatio n rates ranged from 0.28 to 0.51 g TCE/g VSS-d with phenol present, ve rsus an average endogenous rate of 0.18 g TCE/g VSS-d. DCE specific de gradation rates ranged from 0.79 to 2.92 g DCE/g VSS-d with phenol pre sent, versus 0.27 to 1.5 g DCE/g VSS-d for endogenous conditions. Ther e was no inhibition of DCE degradation rates at concentrations as high as 83 mg/L. TCE degradation rates declined between 40 and 130 mg/L TC E. Perchloroethylene, 1,1,1-trichloroethane, and chloroform were not d egraded.