METHOD AND APPARATUS FOR TREATING FOOD WASTEWATER

摘要

PROBLEM TO BE SOLVED: To provide a method and apparatus for treating food wastewater that is high in decomposition and removal ratio in a biological reaction tank without using ozone and that can obtain treated water of good quality. SOLUTION: In the treatment method wherein food wastewater is supplied to a biological reaction tank 5 and a sedimentation basin 11 through a raw water conditioning tank 2 to be treated with activated sludge and a part of sludge is drawn out of the sedimentation basin 11 and/or the biological reaction tank 5 to be treated in an alkali reaction tank 13 to which an alkali agent is added and the treated sludge is returned to the biological treatment tank 5, the alkali agent is added by a pump 14 so that the sludge liquefying ratio in the alkali reaction tank becomes 5-20% and the alkali treated sludge is allowed to flow in the raw water conditioning tank 2 to be brought into contact with raw water in an anaerobic state while mixed with raw mater by a stirring pump 3 and the resulting mixture is allowed to flow in the biological reaction tank 5 and the sludge treated in the alkali reaction tank is pref. set to an amt. of 5-25% by wt. of the sludge of the biological reaction tank.