Effect of mercury reduction of dry batteries on mercury emissions from municipal incinerators in the Ward area of Tokyo, Japan

Abstract

The types and mercury content of dry batteries in municipal solid wastes and the behavior of mercury emissions from a municipal incinerator were investigated in the Ward area of Tokyo, both when a reduction in the mercury content of dry batteries had just commenced and when reduction had been completed. Most of the dry batteries in the wastes were cylindrical (the manganese batteries and the alkaline manganese batteries). The number of manganese batteries, which contained less mercury than the alkaline manganese batteries, accounted for ∼ 70% of the dry batteries in the wastes. The number of R6 and LR6 type batteries accounted for ∼ 60–70% of the manganese batteries and the alkaline manganese batteries, respectively. The mercury content of the manganese batteries and the alkaline manganese batteries were reduced successively and have been reduced to zero since 1991 and 1992, respectively. The reduction in mercury content of the dry batteries was very effective in reducing mercury emissions from the municipal incinerator: the mean mercury concentration was reduced from 0.25 to 0.08 mg/Nm 3, the baseline concentration was reduced from 0.10 to 0.04 mg/Nm 3 and the frequency of high mercury concentrations of > 0.3 mg/Nm 3 were significantly decreased.