| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain a sewage treatment system which has high methane recovery efficiency and high sludge reducing efficiency, which can reduce excess sludge and phosphorus component concentration in treated water. <P>SOLUTION: The sewage treatment system is provided with a 1st settling tank 13 for carrying out solid-liquid separation of the sewage, a biological reaction tank 15, a 2nd settling tank 5 for carrying out solid-liquid separation of activated sludge and a flotation thickening facility 14 including a flotation apparatus for thickening the excess sludge by separation into suspended matter and water. A sludge modifying and separating apparatus 17, which has a sludge modifying means for branching a part of the excess sludge introduced into the flotation thickening facility and changing the excess sludge into a substrate again, an aeration means for blowing microbubbles such as air into the sludge and a sludge separation tank for separating the sludge changed into the substrate into bubbles and liquid and which constitutes a circulatory system thereby, is provided. Thus separated sludge changed into the substrate again and the separated liquid are respectively and individually treated. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
