| 摘要 |
PROBLEM TO BE SOLVED: To provide a biological treatment method and apparatus which can treat organic waste liquid containing high concentrations of SS and nitrogen, such as digested sludge, at a low cost. SOLUTION: In the biological treatment method for treating the organic waste liquid containing high concentrations of SS and nitrogen, the organic waste liquid is treated by directly feeding it to a denitrification tank without separating sludge in the waste liquid, the treated liquid discharged from the denitrification tank is treated in a nitrification tank into which carriers for holding nitrifying bacteria are fed, a part of nitrified liquid after separation of the carriers from the treated liquid is circulated to the denitrification tank and the remainder of the nitrified liquid is subjected to solid-liquid separation, and separated liquid and concentrated sludge are discharged as the treated water and surplus sludge respectively. Digested sludge can be applied as the above organic waste liquid, and it is preferable that a mechanical concentrator is used for the above solid-liquid separation. COPYRIGHT: (C)2005,JPO&NCIPI
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