| 摘要 |
<p>PROBLEM TO BE SOLVED: To stably implement bioreaction by a method in which activated sludge discharged from a bioreactor, after being concentrated/volume-reduced, is returned to the bioreactor. SOLUTION: Drainage introduced to a sewage treatment plant and others is introduced into a bioreactor such as an aerator. An aeration device for aerating drainage is installed in the bioreactor, drainage introduced into the bioreactor is aerated/agitated, organisms (bacteria) in sludge are activated, and organic substances in drainage is treated by aerobic fermentation and others. The biotreated drainage is led to a precipitation tank, where sludge is precipitated naturally to separate sludge from the drainage. Since the concentration of the precipitated/separated sludge is as low as about 1%, this is introduced to a concentrator to make the sludge concentration several %. A mecharical concentrator such as a centrifugal separator is used in the concentration method. The activated sludge after being concentrated/volume-reduced is returned to the bioreactor. In this way, the quantity of organisms necessary for drainage treatment can be maintained without increasing the quantity of activated sludge to be returned to the bioreactor.</p> |
