| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To realize an improvement of treatment efficiency and a reduction of the amount of generated surplus sludge while maintaining a stable treated water quality, in a multistage activated sludge method using predation effects of animalcules. <P>SOLUTION: Organic wastewater is introduced into a first biological treatment tank 1 to oxidatively decompose BOD by bacteria. The treated water of the first biological treatment tank 1 is introduced into a second biological treatment tank 2 to reduce the amount of sludge by performing oxidative decomposition of residual organic components, autolysis of bacteria, and predation by the animalcules. The treated water of the second biological treatment tank 2 is subjected to solid-liquid separation in a sedimentation tank 3 to discharge the separated water outside a system as treated water. A part of the separated sludge is returned to the second biological treatment tank 2, and the remainder is sent to a third biological treatment tank 4 to be aerobically treated. The treated water of the third biological treatment tank 4 is subjected to solid-liquid separation, and solid matter is discharged as surplus sludge, and water is returned to the first biological treatment tank 1 and/or the second biological treatment tank 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
