Thermal Treatment Of POPs-contaminated Soil And Related Flue Gas

With the quick development of industrial production and urbanization, losts of relocated or closed industrial enterperises caused serious POPs contaminated soil. The thermal desorption technology shows good application future in soil remediation. By comparing the pretreatment methods, the analytic method for detecting HCB in contaminated soil was established; Through the thermal desorption system, selecting the appropriate processing parameters to treat HCB contaminated soil; For the degradation of flue fas, a tube furnace was used to simulate the cement kiln calciner, the subjects were HCB, DDTs and HCHs, the system parameters including the treatment temperature, gas residence time, the concentration of pollutants and oxygen content of the atmosphere were examined to evaluate the feasibility of cement kilns treating thermal desorption exhaust.The experimental results indicated that thermal desorption could effectively remove hexachlorobenzene from the soil. When the soil was treated at 450? for 60 min, the removal rate of HCB was 99.4%, which was less than the class A standard of soil quality assessment for exhibition sites. Soil quality meets various types requirements of land use. The thermal desorption process of HCB was not only a physical separation process, but also a reductive dechlorination process. Using a tube furnace to simulate the cement kiln calciner, the process operating parameters were examined the feasibility of cement kiln to treat HCB, DDTs and HCHs exhaust, when the flue gas was treated at 900 ?, the gas residence time of 2 second, the oxygen content in the atmosphere between 2%?7.84%, the removal rate of target pollutant was more than 98%, the residual concentration of dioxins in flue gas was less than the standard for pollution control on co-processing of solid wastes in cement kiln. The cement kiln calciner was suitable for treating the thermal desorption exhaust of HCB?DDTs and HCHs.