FEASIBILITY OF BIODEGRADATION OF TETRACHLOROETHYLENE IN CONTAMINATED AQUIFERS

CHLORINATED SOLVENTS SUCH AS TETRACHLOROETHYLENE, HAVE BEEN SPILLED AND DISPOSED OF ON SOIL AND HAVE BEEN TRANSPORTED TO THE GROUND WATER, CAUSING WIDESPREAD AQUIFER CONTAMINATION. THESE COMPOUNDS ARE OF CONCERN BECAUSE OF THEIR TOXICITY AND SUSPECTED CARCINOGENICITY. CHLORINATED SOLVENTS HAVING THREE OF FEWER CHLORINE ATOMS ARE READILY DEGRADED UNDER AEROBIC CONDITIONS BY METHANE-UTILIZING BACTERIA. TETRACHLOROETHYLENE, HOWEVER, CAN NOT BE DEGRADED BY THOSE AEROBIC BACTERIA. TETRACHLOROETHYLENE CAN, HOWEVER, BE PARTIALLY DECHLORINATED BY ANAEROBIC BACTERIA. CAA BIOREMEDIATION SYSTEMS PROPOSES TO DEVELOP A SEQUENTIAL ANAEROBIC/AEROBIC BIODEGRADATION PROCESS TO BE APPLIED IN THE IN SITU TREATMENT OF TETRACHLOROETHYLENE CONTAMINATED AQUIFERS. THE FEASIBILITY OF THIS APPROACH IS TO BE DEMONSTRATED IN A LABORATORY SCALE AQUIFER SIMULATOR IN WHICH GROUND WATER IS SELECTIVELY AMENDED TO STIMULATE GROWTH OF APPROPRIATE MICROBIAL COMMUNITIES AND IS RECIRCULATED THROUGH CONTAMINATED SOIL. TETRACHLOROETHYLENEIS EXPECTED TO DEGRADE TO TRICHLOROETHYLENE, DICHLOROETHYLENE, AND VINYL CHLORIDE UNDER ANAEROBIC CONDITIONS. IN THE SECOND STEP, THESE COMPOUNDS WILL BE MINERALIZED BY THE METHANE-UTILIZING BACTERIA.