| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To simultaneously and stably remove phosphorus and nitrogen from wastewater by a low aeration activated sludge process, and to keep the costs of facility construction and operation management low by achieving denitrification and dephosphorization treatment in the treatment step of the low aeration activated sludge process without adding a new treatment step. <P>SOLUTION: The wastewater treatment method includes: a reactor 1 for subjecting inflow wastewater containing organic matter to low aeration treatment; a precipitation tank 2 for subjecting the treated water of the low aeration treatment to precipitation separation treatment; and a sludge digestion tank 3 for subjecting the precipitated sludge which has been precipitated and separated to low aeration treatment again. Supernatant water obtained in the sludge digestion tank 3 is mixed into the inflow wastewater. In the method, an ignition residue concentration in the supernatant water of the sludge digestion tank 3 is kept higher than that in the inflow wastewater. The ignition residue concentration in the supernatant water is≥300 mg/L, and DO in the reactor 3 is≤1 mg/L. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
