A method and apparatus for minimizing the environmental release of acids and toxic organic compounds from a waste incinerator-air pollution control train. The apparatus comprises an incinerator, a gas cooling means such as a waste heat boiler or quench chamber, a means for the partial removal of acid gases and dioxins by contact with either finely- divided alkaline solids or alternatively, by an alkaline solution in a spray drier-absorber, a dry solids collection means such as a fabric filter or electrostatic precipitator, a wet scrubber means for residual metal, dioxin/acid gas removal and an induced draft fan. In the method of this invention, the final wet scrubber stage operates without alkaline neutralization, but under scrubber acid concentrations and operating conditions that provide an exhaust gas within compliance limits of emission regulations. The contaminated liquor blowdown from the wet scrubber, which contains toxic organics and acids, is recycled back into the incinerator. The aqueous acid liquor blown down to the incineration is vaporized therein, most of the toxic organic content of the liquid is destroyed by the re-incineration, and the regenerated acid gases are largely removed by the first dry scrubbing stage.
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