Abstract
In this study, a calcination process was applied to destroy dioxins in sediments highly contaminated with them on a pilot scale (10 kg sediment/hr of treatment capacity). Treatment process involved apparatus of dewatering, size classification and aggregation of sediments, rotary kiln, secondary burner and bag filter. A remarkable reduction of the dioxin content (2, 900 and 11, 000 pg-TEQ/g for two test samples) in sediments to less than 0.033 pg-TEQ/g was achievable. In addition, from a physical point of view, the treated sediments possessed appropriate strength and water permeability comparable to those of sand, which leads to use of the treated sediments construction materials. The applied process could comply with dioxin emission limits in Japan for air and residual samples (i. e., treated sediments and fly ashes). Through a treatment system, high destruction efficiency (DE) values of greater than 99.99 percent were demonstrated for dioxins and their TEQs. DEs of greater than 99.4 percent were also found for PCBs (>99.91%), chlorobenzens (>99.97%), chlorophenols (>99.93%), polychlorinated naphthalenes (>99.96%) and polyaromatic hydrocarbons (>99.4%).
