Reductive dechlorination of perchloroethylene using anaerobic sequencing batch biofilm reactors (AnSBBR)

Chlorinated organic solvents, such as perchloroethylene (PCE) and trichloroethylene (TCE), rank in the top five of the groundwater pollutants found in the United States. During the past year, the Anaerobic Sequencing Batch Biofilm Reactor (AnSBBR) was used to select for, enrich, and modify the physiological state of one or more of the many possible microbial consortia that can participate in the reductive dechlorination of PCE. Reactors enriched on lactate or acetate were able to dechlorinate 10.5 mg (63.3 μmoles) of PCE to cis -1,2-dichloroethylene (cDCE) on a daily basis. When methanol was used as the electron donor PCE, TCE, and cDCE were detectable in the reactor at the end of a 24 hour cycle. An AnSBBR fed only H 2 /CO 2 was able to mediate the dechlorination of PCE to TCE, cDCE, and vinyl chloride (VC). Chloride measurements provided for a reliable and accurate method for the quantification of reductive dechlorination when the sorption of the chlorinated ethylenes affected the direct measurement of these compounds.