Biodegradation of Chlorinated Ethenes in Mixed Waste Streams

摘要

This report summarizes research conducted from 04/01/01 to 08/31/04 with support from the US Army Research Office DoD-EPSCoR program. The goal of the research was to study the biodegradation of chloroethenes under serial anaerobic/aerobic conditions. In the system used water flowed through a contact chamber containing chloroethenes. Contaminated water was then pumped through a sediment column. From the sediment column the water flowed into an aerated chamber. Chloroethenes concentrations were determined in samples from the contact chamber the sediment column and the aerobic chamber. We tested means for establishing anaerobiosis in the sediment column two sparging gas mixtures addition of lactate as a growth substrate control of conditions in the aerobic chamber and the presence of a hydrocarbon fuel mixture as a co-contaminant. Results indicated that a N2:H2 gas mixture stimulated POE degradation. We also found that the addition of exogenous lactic acid (2 mM) and the presence of petroleum hydrocarbons in reactor feed water resulted in 99.6% removal of PCE and 99.2% reduction in the total molar concentration of chloroethenes. In the last year of the research we established mixed microbial cultures in which vinyl chloride disappearance was concomitant with an increase in chloride concentration and biomass accumulation.