| 摘要 |
<p>PURPOSE:To contrive efficient dephosphorization in parallel with the removal of BOD from organic liquid waste and its nitrification-denitrification, by anaerobically treating a liquid to be treated while adding activated sludge to it, and then simultaneously performing aeration and nitrification using a microbic bed on which nitrifying bacteria are implanted. CONSTITUTION:A liquid 11 to be treated, i.e. organic liquid waste containing BOD, phosphorus and reduced nitrogen compounds such as NH4<+>, is introduced into an anaerobic tank 1, mixed with returned activated sludge 15 and anaerobically treated by agitatively mixing it under a condition substantially free from any of DO and NOX, to discharge phosphorus from the activated sludge and to absorb BOD. Thereafter, the anaerobically treated liquid 12 is introduced into an aeration tank 2 and aerated therein while oxidatively nitrifying NH4<+> into NOX by nitrifying bacteria implanted on a microbic bed 3. Hereon, phosphorus at the site of the solution is absorbed in the sludge again. The aerobically nitrified liquid 13 is then introduced into the final precipitation pool 4 to separate the treated liquid 14. A part of precipitating activated sludge is withdrawn as excess sludge 16, while most of it is circulated as returned activated sludge 15 to the anaerobic tank 1 after agitating it in a denitrification tank 5 for a predetermined time at need to remove NOX.</p> |
