| Mercury is a kind of global pollutant, which is of durability, easy mobility, and high bioaccumulation. Environmental mercury pollution has been drawn worldwide attention of researchers all over the world. The municipal solid waste(MSW) incineration is one of the main anthropogenic sources of atmospheric mercury emissions in the world. To improve the understandings of mercury pollution from municipal solid waste incineration plants and make effective mercury control policies to control atmospheric mercury emission, it is imperative to study the emission characteristics of atmospheric mercury from municipal incineration process and provide atmospheric mercury emission inventory of China ’s MSW incineration industry.In this study, to get the distribution of mercury contents in MSW, typical MSW incineration plants of Shanghai, Guangzhou, C hongqing and Wuhu were chosen to carry the test and analyzed for mercury contents of MSW component. With mercury content of each waste component, mercury consumption of mercury-containing waste and composition proportions of each MSW component, the mercury contents distribution data of MSW in China was estimated. Mercury concentration of exhaust gas, fly ash and slag were analyzed according to the on-site measurements in three MSW incineration plants. The mercury removal efficiency of air pollution control devices, mercury emission factor and chemical speciation in flue gas were obtained in plants. The atmospheric mercury emissions from MSW incineration industry in 2012 were calculated based on the incineration weight of MSW, mercury contents of MSW, and mercury removal efficiency of air pollution control devices, its uncertainty was analyzed as well. Scenario analysis was further conducted to study the mercury emission control potential of MSW incineration industry in C hina. Mercury emission control technology applied to MSW incineration plants was discussed.Results of this study show that mercury content in domestic municipal solid waste was 0.56g·t-1. Mercury content of MSW in domesticmost provinces was close. Mercury concentration of exhaust gas in Guangzhou, C hongqing, and Wuhu MSW incineration plants were(9.5±3.9),(26.4±22.7) and(24.1±6.0) μg·N m-3 respectively; Atmospheric mercury emission factors of Guangzhou and Wuhu incineration plants were(0.001, 0.032) g·t-1,(0.11, 0.38) g·t-1 in 80% confidence interval respectively, and the atmospheric mercury emission factor of C hongqing incineration plant was(0.13±0.11) g·t-1. The mercury removal efficiency of air pollution control devices in tested incineration plants was 33.7%-96.7%, which has large difference. In year of 2012, atmospheric mercury emissions of MSW incineration industry was 9.8(-3.7,3.8) t in C hina, of which the grate furnace, fluidized bed and other burning process accounted for 61.9%, 36.4%, 1.7% respectively. The primary atmospheric mercury emissions were Jiangsu, Zhejiang, Guangdong, Shandong and Fujian provinces. Particulate mercury(Hgp), gaseous oxidized mercury(Hg2+), and gaseous elemental mercury(Hg0) of atmospheric mercury emissions were 0.10 t, 8.08 t and 1.59 t respectively, which gaseous oxidized mercury accounted for 82.7%. The atmospheric mercury emission factors of grate furnace, fluidized bed and other burning process were 0.26g·t-1, 0.30g·t-1 and 0.27g·t-1 respectively. Atmospheric mercury emission factors of most domestic provinces were close. The mercury emissions from MSW incineration industry will decrease in year of 2020 through controlling the total amount of MSW and improving mercury removal efficiency of air pollution control devices. |
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