Behavior of PCBs and Dioxins during Thermal Remediation of Contaminated Soil Containing Waste

Soil contaminated with PCBs and dioxins was remediated using an intermediate air intake rotary kiln with a low oxygen process combining high-temperature (1100°C or higher) oxidation. The concentration of dioxins in the treated soil and burned ash was 0.0038–6.1 pg-TEQ/g and the concentration of PCBs was 0.91–3.3 ng/g. The dioxin concentration in the treated exhaust gas was 0.016/0.011 pg-TEQ/m3N and the PCB concentration was 14/4.7 ng/m3N. These results were all cleared for Japanese Environmental regulations. It also revealed that PCB particles could be easily collected using a bag filter because the majority of PCBs in the flue gas emitted from the kiln were in particle form. In addition, these particle-bound PCBs were not regenerated in the kiln or secondary combustion chamber. It is resulted that this combined process is suitable for the remediation of contaminated soil containing waste.