Removal of PCBs and HCB from contaminated solids using a novel successive self-propagated sintering process.

ABSTRACT

Thermal treatments are the primary technologies used to remove persistent organic pollutants from contaminated solids. The high energy consumption during continuous heating, required cost for treating the exhaust gas, and potential formation of secondary pollutants during combustion have prevented their implementation. A novel successive self-propagated sintering process was proposed for removing polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) from contaminated solids in a low-cost and environmentally friendly way. Nine laboratory-scale experiments involving different initial concentrations of pollutants and solid compositions were performed. Almost all PCBs (>99%) and HCB (>97%) were removed from solids under constant experimental conditions. Varying initial concentrations of PCBs and HCB in the contaminated solids did not influence the removal efficiency of the pollutants; however, the degradation efficiency of pollutants increased as their initial concentrations increased. Although varying levels of PCDD/Fs were detected in the effluent gas, they were all within the emission standard limit.