| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a treating method of an organic waste liquid and the device decreased in quantity of sludge discharged out of the system at low cost by reducing volume of the sludge without increasing capacity of an aeration tank and the quantity of oxygen to be supplied in an aerobic treating process, prevented in deterioration of quality of the treated liquid and capable of recovering resource and energy as a form of methane. SOLUTION: A mixed liquid aerobically biologically treated by activated sludge in the aeration tank 1 is solid-liquid separated in a settling tank 2, a part of the separated sludge 18 is taken out, the taken-out sludge 22 is brought into contact with ozone 25 in an ozone treating tank 3 to be reformed easily decomposable, the ozone treated sludge 26 is kept in an anaerobic state in an acid generating tank 4 to generate an organic acid. The acid generated liquid 28 is separated by a membrane separation device 5, the concentrated liquid 40 is returned to the acid generating tank 4 and the permeated liquid 39 is methane fermented in a methane fermentation tank 6 and after that, returned to the aeration tank 1 to be aerobically biologically treated.</p> |
