| 摘要 |
PURPOSE:To sufficiently remove mercury in exhaust gas washing water, by adding an oxidizing agent to exhaust gas washing water, to which the vaporization treatment of mercury is applied, to oxidize the residual reducing agent while neutralizing the excessive oxidizing agent by a reducing agent and subsequently applying sulfide flocculation treatment to said washing water. CONSTITUTION:Alkali washing water of incinerator exhaust gas is introduced into a reductive reaction tank 1 and ionic mercury in the washing water is converted to metal mercury by a reducing agent while the treated washing water is introduced into a vaporization apparatus 2 where vaporizing gas is blown into the washing water to allow metal mercury to follow the vaporizing gas. This vaporizing gas is cooled by a cooler 3 to transfer mercury to the condesnate and metal mercury is recovered from the condensate in a solid-liquid separation tank 4. Vaporization treated water from the vaporization apparatus 2 is oxidized in an oxidizing tank 6 and subsequently guided to a reducing tank 7 to neutralize the oxidizing agent by reducing treatment. Subsequently, the treated water is guided to a sulfide reaction tank 8 where sodium sulfide or ferric chloride is added to perform sulfide flocculative precipitation treatment.
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