APPARATUS FOR REMOVING HEAVY METAL IN SEWAGE SLUDGE

摘要

PURPOSE:To efficiently remove heavy metals, by adding caustic potash to treated sludge from an alkali treatment process to saponify said sludge and foaming the sludge by aeration. CONSTITUTION:Conc. sludge is charged in a mixing tank 1 and KOH is added to said sludge under stirring to make the sludge alkaline so as to have pH of about 10. An alkali treatment tank 2 consists of treatment tanks 21-26 and allowed to stand to make concn. distribution uniform. Subsequently, sludge after alkali treatment is sent out to a soap flotation apparatus 3 by a sludge feed pump P by the change-over control of a discharge valve in a day unit. Then, the sludge is foamed by an air diffusion system discharging compressed air into conc. sludge by a supply pump to be subjected to aeration. By this method, a heavy metal can be removed efficiently.