WATER CLEANING METHOD AND WATER CLEANING PLANT

摘要

PROBLEM TO BE SOLVED: To prevent leakage of pathogenic microorganisms into treated water. SOLUTION: The upper part of a septic tank 20 is compartmentalized to a flotation region 20A and the lower part thereof to a membrane filtration region 20M. The upper part of the flotation region 20A is provided with a raw water nozzle 21 and the lower part is provided with a pressurized water nozzle 22. The membrane filtration region 20M is provided with an immersion type permeable membrane module 23. The pressurized water mixed and dissolved with air is introduced from the pressurized water nozzle 22 to form an air bubble zone Z. The raw water subjected to flocculation treatment is introducing therein from the raw water nozzle 21 and is passed through the air bubble zone Z by downward current and is then passed through the immersion type permeable membrane module 23.