A Study of Factors Controlling the Rate of Biodegradation of Tetrachloroethylene for the Remediation of Illegal Dumping Sites

摘要

Batch tests were conducted in which tetrachloroethylene (PCE) was degraded by indigenous bacteria within actual dumped waste samples under anaerobic conditions. The effects of the different kinds of wastes, incubation temperature, and the injection of nutrients on the biodegradation rate were investigated. First, in order to calculate the mass balance of PCE and its degradation by-products, such as trichloroethylene (TCE), cis-1,2-dichloroethylene (cis-1,2-DCE), vinylchloride(VC) and ethylene, gas-liquid and liquid-solid partition coefficients of PCE and its degradation by-products were determined for three types of waste samples obtained from an illegal dumping site. Results of batch tests revealed that about 90% of injected PCE was dechlorinated to VC and ethylene at 25℃ by indigenous bacteria in the bark waste samples. The biodegradation rate of PCE in the sludge waste samples was slower than that in the bark waste samples. However, the injection of glucose as nutrient increased the biodegradation rate of PCE in the sludge waste sample. The biodegradation rate of cis-1,2-DCE to VC was slow at incubation temperatures of 10℃ and 15℃. At 25℃ the biodegradation rate of cis-1,2-DCE to VC and ethylene increased.