Use of bioaugmentation to stimulate complete reductive dechlorination of trichloroethene in dover soil columns

Soil columns were constructed in support of the Remediation Technologies De velopment Forum accelerated biodegradation study at Dover Air Force Base to evaluate the impact of amendments on the anaerobic reductive dechlorinatio n of trichloroethene (TCE) in Dover soil. Dechlorination of TCE to cis-dich loroethene (c-DCE) was observed in the columns using lactate, lactate and m ethanol, butyrate, glutamate and 1,2-propanediol, or toluene as electron do nors, in combination with vitamins and other supplemental nutrients. Howeve r, the c-DCE formed was not further dechlorinated using any of these amendm ents. Subsequent inoculation of two columns with a competent, nonnative TCE -dechlorinating culture resulted in the dechlorination of TCE to ethene aft er 30 days. Once the culture was established, dechlorination of TCE to ethe ne was complete in the first several centimeters of the columns at TCE infl uent concentrations of ti mg/L. The culture was also able to dechlorinate T CE to ethene when TCE influent concentrations were increased to 170 mg/L. T hese results suggest that a critical bacterial population was missing in th ese soils and that bioaugmentation is an appropriate remedial strategy unde r such circumstances.