| 摘要 |
<p>PURPOSE:To remove the nitrogen in sewage by providing a sedimentation tank or an anaerobic filter-bed tank in the preceding stage of a fluidized-bed aeration tank and a contact aeration tank in the succeeding stage, and circulating the treated water from the contact aeration tank to the sedimentation tank or anaerobic filter-bed tank in the preceding stage. CONSTITUTION:Sewage is sent to the anaerobic filter-bed tank 4 through a flow control tank 1, the impurities and SS are removed therein, and the sewage is sent to the fluidized-bed aeration tank 5. The sewage is circulated in the tank 5 along with the filter medium 1, BOD is decomposed by the microbes on the surface of the filter medium 11, and the treated water flows into the contact aeration tank 7. The SS is collected by the contact filter medium 14 in the contact aeration tank 7, and the ammoniacal nitrogen is converted to nitrate nitrogen. The treated water from the aeration tank 7 is circulated to the anaerobic filter-bed tank 4, and the nitrate nitrogen in the circulating water is decomposed by the BOD is raw water into gaseous nitrogen.</p> |
