Photodegradation of PCBs in surfactant-washed soils

Laboratory-scale studies were conducted to determine bioavailability-based endpoints for an innovative treatment process involving soil flushing with surfactants and above-ground treatment of surfactant wash water by photolysis, followed by aerobic bioremediation. In the present paper, we report on the surfactant washing of PCB-contaminated soils and UV-irradiation of soil wash waters. 85% of the Soxhlet extractable PCBs were removed with three successive wash cycles using a surfactant mass loading ratio of 0.1 g polyoxyethylene 10 lauryl ether/g soil. Photolysis of the resulting wash water successfully dechlorinated 40% of the PCBs in solution, paving the way for facile bioremediation in subsequent steps. The cost of soil washing and photolysis using this process was estimated to be $0.454/kg or about $450 per metric ton of soil.