| 摘要 |
<p>PURPOSE:To obtain a method for preventing bulking with low cost and providing prevention by mixing ozone with a low concn. in an aeration air in a process wherein air for activated sludge treatment is blown in to perform aeration. CONSTITUTION:It has been believed that ozone has a strong sterilization power and kills bacteria but when the concn. is such a low concn. as at least 100ppm and at most 400ppm, no QX sterilization action works on aerobic bacteria and sterilization is effective only to molds. Therefore, ozone with a relatively low concn. of at least 100ppm and at most 400ppm mixed in air for aeration does not kill aerobic bacteria but kills selectively the molds. In addition, ozone after killing the molds is decomposed into oxygen and does not remain. Therefore, as it kills only the molds which causes bulking, even if activity of the aerobic bacteria is weakened, sedimentation speed of sludge is not largely lowered and bulking can be prevented.</p> |
