| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve the quality of treated water in an aeration tank provided with a membrane separator inside by aerobically treating and membrane- separating waste water and solubilizing a part of the liq. mixture in the aeration tank in a solubilization tank. SOLUTION: A membrane separator 2 is provided to an aeration tank 1. The solid-liq. separation of waste water by the membrane separator 2 and the biological digestion by aeration are performed in parallel, the liq. mixture contg. sludge and being aerated is appropriately withdrawn and introduced into the subsequent solubilization tank 3. The solid component of the sludge is converted to a water-soluble component in the solubilization tank 3, the solubilized liq. is returned again to the aeration tank 1, and the org. component is converted to the gas by biological digestion. Accordingly, the amts. of the soluble org. matter, gel component and fine solid component contained in the membrane-separated water discharged from the tank 1 are decreased, and the quality of the treated water is drastically improved.</p> |
