| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a multistage active sludge process utilizing the predatory activity of small organisms, in which while maintaining the stable quality of treated water, further enhancement of disposal efficiency and reduction of the volume of excess sludge generated can be realized. <P>SOLUTION: Organic waste water is introduced into a first biological treatment tank 1, and BOD is decomposed oxidatively. The treated water in the first biological treatment tank 1 is introduced into a second biological treatment tank 2, and, the remaining organic components are decomposed oxidatively, non-agglomerative bacteria are autolyzed and the volume of sludge is reduced by predatory activity of small organisms. The treated water in the second biological treatment tank 2 is separated into water and sludge in a precipitation tank 3, and the sludge in the second biological treatment tank is discharged by 1/5 to 1/40 per day in such a manner that the residence time of the sludge in the second biological treatment tank reaches 5 to 40 days. The sludge in the second biological treatment tank is discharged by the prescribed amount in this way, and the small organisms and excrement present in the second biological treatment tank are thinned out, thus the small organisms in a state of being capable of laying eggs can be held within the second biological treatment tank by a fixed amount always in a relatively high ratio. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
