SEPTIC TANK

摘要

PROBLEM TO BE SOLVED: To sufficiently remove nitrogen by agitating a sewage in an aeration tank at the time of an anaerobic treatment. SOLUTION: In a purifying tank, a membrane separation type aeration tank 2 executing an aerobic treatment and an anaerobic treatment intermittently and executing a nitrogen removal at the time of the anaerobic treatment is provided and a storage tank 11 storing a filtered water after membrane separation is provided at a post stage of the aeration tank 2. In this case, a water supplying.agitating means 12 and 15 supplying the filtered water in the storage tank to the aeration tank and agitating at the time of the anaerobic treatment of the aeration tank is provided.