| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a treatment method for organic waste water by which the recovery efficiency of methane gas can be increased while highly maintaining the quality of treated water in a method where, at the time of treating organic waste water by an activated sludge process, a part of excess sludge is subjected to anaerobic digestion treatment, so as to generate methane gas useful as energy. <P>SOLUTION: Organic waste water is mixed with returned sludge and is subjected to aeration treatment in an aerator 1, and thereafter, solid-liquid separation is performed. A part of the separated sludge is made into returned sludge, and another one part is subjected to anaerobic digestion treatment in an anaerobic treatment tank 3. A part of the returned sludge is subjected to aeration treatment in a re-aerator 4 and is thereafter returned to the aerator 1, and the balance is returned to the aerator 1 as it is. By shortening SRT (sludge retention time) in the aerator 1 to≤3 days, while the decomposition rate of organic matter in the aerator 1 is made low, the reproduction rate of microbial cells can be increased. Further, by the returned sludge subjected to the aeration treatment, the decomposition rate of the organic matter is increased and SRT is shortened, thus deterioration in treated water can be prevented. The generation of a large quantity of methane gas is made possible. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
