ABSTRACT
Microorganisms mediate the sequential dechlorination of perchloroethylene (PCE) to trichloroethylene, dichloroethylene, vinyl chloride, and, ultimately, ethylene, a nontoxic compound. Researchers have focused on PCE dechlorination in strict anaerobic environments while little or no data have been published on the effects of oxygen concentration on this process.
In this experiment, sequencing batch reactors contained aerobic/facultative anaerobic mixed cultures which could dechlorinate PCE during anaerobic periods, with glucose as a carbon and energy source, despite experiencing an aerobic period during the cycle. The acclimated enrichment cultures were able to dechlorinate 90 to 95% of 10 mg/L of PCE to cis-1,2-dichloroethylene (cDCE). The cultures were exposed to 8–9 mg/L of oxygen for 1.0 hour every 24 hours. This report represents a major step toward the creation of a single biological reactor than can promote both PCE dechlorination and oxidation of the dechlorination products.
