Formation and control of toxic polychlorinated compounds during incineration of wastes containing polychlorinated naphthalenes

To estimate the potential impact on municipal solid waste (MSW) incinerator toxic equivalent (TEQ) emissions of treating wastes containing polychlorinated naphthalenes (PCNs), pilot-scale thermal treatment experiments were conducted. MSW (run 1) and MSW fortified with synthetic rubber belts containing PCNs (runs 2 and 3) were incinerated. Flue-gas and ash samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), coplanar polychlorinated biphenyls (co-PCBs), and PCNs. Final exhaust-gas WHO-TEQ emissions were all less than 0.1 ng/Nm3. Flue-gas TEQs were mainly from PCDFs (58-74%). When 2,3,7,8-tetrachlorodibenzo-p-dioxin relative potency factors (REPs) of specific PCN congeners from previous reports were used as estimated toxic equivalency factors to compute estimated PCN TEQs and total TEQs along with PCDDs, PCDFs, and co-PCBs, the contributions of PCNs to the total TEQs were small in ash samples and up to 28% in final exhaust gas. The TEQs in primary combustion flue gases increased through the formation of dioxins and PCNs and then decreased via secondary combustion, fabric filtration, and activated carbon adsorption. From this pilot-scale study, the incremental impact of incinerating PCN-containing wastes on annual TEQ emissions in Japan is estimated as 0.27 g of total TEQ.