BIOLOGICAL FILTER TYPE WASTE WATER TREATING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a biological filter type waste water treating device capable of reducing the amount of waste water in back wash and capable of increasing SS concn. in the backwashing waste water. SOLUTION: A water permeable supporting member 2 is installed horizontally at the upper part of a filter tank 1 and a floatable filter medium layer 3 is formed below the member 2. A storage tank 4 of the backwashing water is installed above the water permeable supporting member 2. A backwashing discharge pipe 6 is connected to the lower part of the filter tank 1, and a backwashing discharge valve is disposed midway. A return pipe 8 provided with a valve 9 is branched from the midway of the backwashing discharge pipe 6.