| 摘要 |
<p>PURPOSE:To reduce the formation of excess sludge nearly into zero, by laying pipes for charging raw sewage to a biomembrane unit and to an aerating tank, and a pipe for transferring sewage treated in the biomembrane unit to the aerating tank. CONSTITUTION:In a plant described in the title, which is composed of an aerating tank 1, a settling and separating tank 2 for sludge, a returning pipe 3 for sludge, and a biomembrane unit 4, raw sewage is treated by charing both to the biomembrane unit 4 and to the aerating tank 1, ratio of quantities of sewage to be charged to said tank and unit being adjusted in accordance with conditions. Use of the plant of said composition allows to increase the disappearance rate of the formed sludge by solubilization or digestion, to decrease the formation of sludge remarkably without change in removal efficiency for COD, hence treating cost is reduced.</p> |
