| 摘要 |
<p>PURPOSE:To prevent both flotation of ppt. in a precipitation tank and outflow of sludge by allowing immobilized microorganisms incorporating nitrite bacteria, nitrate bacteria and denitrification bacteria to be present together with activated sludge in a sewage treating tank and bringing the immobilized microorganisms into contact with sewage in the aerobic atmosphere. CONSTITUTION:Since immobilized microorganisms incorporating nitrite bacteria, nitrate bacteria and denitrification bacteria are allowed to be present in a sewage treating tank such as an aeration tank, organic nitrogen incorporated in sewage is changed into nitrate nitrogen via ammoniac nitrogen and nitrite nitrogen by bringing the immobilized microorganisms into contact with sewage in the aerobic atmosphere. However in the case of using immobilized microorganisms, since the insides thereof become an anaerobic state, nitrate nitrogen receives action of denitrification bacteria in the insides of immobilized microorganisms and is converted into gaseous nitrogen. Nitrate nitrogen incorporated in treated water sent to a precipitation tank is extremely reduced. Accordingly generation of gaseous nitrogen due to denitrification bacteria in the precipitation tank is made extremely little and flotation of sludge is not caused.</p> |
