| 摘要 |
<p>PURPOSE:To simultaneously remove BOD, nitrogen and phosphorus in sewage, by a method wherein org. sewage is subjected to aerobic reaction due to a fixed microorganism and a floated microorganism and guided to a solid-liquid separation apparatus to obtain treated water while a part of the separated sludge is returned to an anaerobic region. CONSTITUTION:After org. sewage 55 and sludge are introduced into an anaerobic tank 51 to be subjected to anaerobic reaction due to a floated microorganism, the treated sewage is introduced into an aerobic tank 52 to receive the supply of oxygen and aerobic reaction is performed by the microorganism fixed to a filter material 56 and the floated microorganism in the aerobic tank 52. Subsequently, the treated sewage is guided to a precipitation tank 53 to obtain treated water 57 and a part of the separated sludge 54 is returned to the anaerobic tank 51. In this case, it is desirable that the contact of org. sludge 55 and sludge are accelerated in the anaerobic tank 51 and both of them are stirred and mixed by a stirrer or a pump in order to prevent sludge precipitation. As the filter material 56 for holding a biological membrane, a granular material or a honeycomb tube can be used.</p> |
