| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To restrain lowering of the pH of a membrane-permeated water and to prevent the production of scale when nitrogen-containing organic sewage is treated by a membrane separation type activated sludge treatment method. <P>SOLUTION: When the nitrogen-containing organic water to be treated is treated by the membrane separation type activated sludge treatment method, the amount of excess sludge to be withdrawn from a biological reaction tank 4 is controlled so that SRT is within five days, the SRT being defined as a value which is obtained by dividing the amount of the total activated sludge amount in the biological reaction tank 4 by the excess sludge withdrawn from the biological reaction tank 4, and MLSS (mixed liquid conc.) in the biological reaction tank 4 is kept within the prescribed concentration by taking out the membrane-permeated water of the prescribed amount through a tank immersion type membrane separation unit 5 immersed in the biological reaction tank 4. <P>COPYRIGHT: (C)2004,JPO</p> |
