A Study on Remediation of PCBs-Contaminated Soil by a Combination of Biosurfactant Washing, UV-Irradiation and Biodegradation

摘要

Remediation of PCBs-contaminated soil by a combination of rhamnolipid (RL) biosurfactant washing, photolysis and biodegradation was studied. The results showed that rhamnolipid obviously enhanced desorption of PCBs from soils, and the total amount of PCBs desorbed increased with increasing RL concentration. After three batch washes, the total amount of PCBs removed from the laboratory contaminated soil and the field contaminated soil was 90.1% and 47.1%, respectively. UV-irradiation resulted that 76.4% of the total PCBs was photodegraded and the relative concentration of highly chlorinated congeners decreased by more than 86% after 150 minutes. Without any photolysis, nearly 79.5% and 81.4% of the total PCBs in the 39.68 mg/L and 58.60 mg/L of PCBs solutions were biodegraded in 48 h, respectively. With 10 minutes of precedent UV-irradiation, the 39.68 mg/L of PCBs solutions exhibited a 92.8% of PCBs biodegradation in 48 h, and the biodegradation rate of highly chlorinated congeners was increased apparently. Seemingly, precedent photolysis obviously improved the overall biodegradation of the congeners in PCBs.