APPARATUS FOR SELENIUM RECOVERY

PROBLEM TO BE SOLVED: To enable the selenium recovery and selenium removing treatment of drainage containing selenium by a method in which biological sludge containing selenium is heated, gas containing oxygen for combustion is introduced to evaporate selenium and burn the residue, combustion exhaust gas is introduced into a selenium condenser to make selenium be condensed selectively. SOLUTION: Drainage containing selenium which is removed of heavy metals other than selenium by a pretreatment apparatus 12 is treated by a biological/ chemical treatment apparatus 14, a reduced pressure heating apparatus 16, and a dewatering apparatus 18 to obtain biological sludge of about 30% water content. Selenium is heated and evaporated with air for combustion supplied while the sludge is being heated by a heating furnace in a sludge burning apparatus 20, and the residue is made to be burned. Generated combustion exhaust gas is introduced into an exhaust gas cooler, and a selenium simple substance and/or selenium oxide are made to be condensed selectively. Selenium particles and selenium oxide particles in the combustion exhaust gas are recovered by a bag filter. In this way, a closed system is constituted, and selenium is recovered to prevent environmental pollution.