FIELD-EVALUATION OF IN-SITU AEROBIC COMETABOLISM OF TRICHLOROETHYLENE AND 3 DICHLOROETHYLENE ISOMERS USING PHENOL AND TOLUENE AS THE PRIMARY SUBSTRATES

The Moffett field site was used for further evaluation of in situ biotransformation of chlorinated aliphatic hydrocarbons with phenol and toluene as primary substrates. Within the 4 m test zone, representing a groundwater travel time of less than 2 days, removal efficiencies for 250 mu g/L TCE and 125 mu g/L cis-1,2-dichloroethylene were greater than 90%, and that of 125 mu g/L trans-1,2-dichloroethylene was similar to 74%, when either 9 mg/L toluene or 12.5 mg/L phenol was used. Phenol and toluene were removed to below 1 mu g/L. Vinyl chloride removals greater than 90% were also noted. However, only 50% of the 65 mu g/L 1,1-dichloroethylene was transformed with phenol addition, and significant product toxicity was evident as concomitant TCE transformation was here reduced to similar to 50%. Hydrogen peroxide addition performed as well as pure oxygen addition to serve as a required electron acceptor.