METHOD FOR TREATING SEWAGE AND CIRCULATION TAPE NITRIFICATION AND DENITRIFICATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for treating sewage based on an activated sludge process and a circulation type method for nitrification and denitrification which solves a problem accompanied by solid-liq. separation by a final sedimentation basin in the conventional activated sludge process by utilizing a filtration equipment and furthermore, stably obtains good quality of treated water. SOLUTION: In a method for treating sewage wherein a filter body 5 which is a hollow filter body 5 with an inlet part consisting of a water permeable supporting material at least as a part of a surrounding wall and an outlet part as an opening and performs filtration by forming a filtration film comprising activated sludge and turbid substance is arranged by submerging it in at least one of a biological reactor and a final sedimentation basin and treated water is drained from the filter body 5 through the outlet by water head difference to the following tank, a coagulant is added in at least one of raw water being an object to be treated or the biological reactor 2.