| 摘要 |
PROBLEM TO BE SOLVED: To provide a drainage processing system and method capable of making supply of ozone for the purpose of improving a drainage processing capability by improving a biological treatment capability, improving sludge settleability by suppressing filamentous fungi propagation, preventing a bulking obstacle and reducing the sludge generation amount, compatible with sludge flow-out prevention using a membrane.SOLUTION: A drainage processing system for treating organic wastewater includes: an active sludge tank for biologically treating the organic wastewater which flows in while containing active sludge; an ozone supplying device which adds ozone to the active sludge within the active sludge tank; an immersion membrane tank which purifies the organic wastewater sent from the active sludge tank by means of an immersion membrane disposed within the tank; and a retention means which is provided in the middle of a path connected from the active sludge tank to the immersion membrane tank for retaining the organic wastewater sent from the active sludge tank to the immersion membrane tank for such a predetermined time or longer that the ozone concentration of the organic wastewater passing the immersion membrane becomes less than or equal to an allowable ozone concentration of the immersion membrane. |
