[Mercury Emission Characteristics and Mercury Concentrations of Municipal Solid Waste in Waste Incineration Plants]

Municipal solid waste (MSW) incineration is one of the most important atmospheric mercury emission sources. To investigate the mercury concentrations of MSW and mercury emission characteristics in incineration plants, this study analyzed the MSW sampled in 3 typical MSW incineration plants in Shanghai, Guangzhou and Wuhu respectively. The exhaust gas samples in incineration plants were sampled by using OH (Ontario Hydro) method. The mercury concentrations in fly ash, and bottom ash samples were also analyzed. The results indicated that mercury concentrations of MSW in Shanghai, Guangzhou, and Wuhu incineration plants were (0.39±0.04) mg·kg^-1, (0.57±0.05) mg·kg^-1, and (0.27±0.08) mg·kg^-1 respectively. The mercury concentrations of exhaust gas in Guangzhou, Wuhu MSW incineration plants were (9.5±3.9) μg·m^-3 and (24.1±6.0) μg·m^-3 respectively; Particulate mercury (Hg_p), gaseous oxidized mercury (Hg²⁺), and gaseous elemental mercury (Hg⁰) represented (0.9±0.8)%, (89.0±5.4)%, (10.1±4.6)% in Guangzhou MSW incineration plant, and (1.0±0.8)%, (65.4±27.6)%, (33.6±27.5)% in Wuhu MSW incineration plant, respectively. Gaseous oxidized mercury (Hg²⁺) of exhaust gas in different incineration process showed different distribution proportions. Besides, mercury removal efficiency of Guangzhou, Wuhu MWS incineration plants was 96.7% and 33.7%, respectively. The atmospheric mercury emission factors of Shanghai, Guangzhou, and Wuhu MSW incineration plants were (0.156±0.016) mg·kg^-1, (0.019±0.002) mg·kg^-1, (0.178±0.027) mg·kg^-1 respectively. Compared with MSW incineration plants in Japan and Korea, the atmospheric mercury emission factor of Guangzhou incineration plant was slightly lower; Atmospheric mercury emission factors of Shanghai and Wuhu MSW incineration plants were close to those of domestic fractional MSW incineration plants.