| 摘要 |
PURPOSE:To attain to lower the conc. of NO2 and NO3 in waste water supplied to post-treatment equipment from an aeration tank, in treating waste water from a second denitrification tank in the aeration tank, by supplying the waste water from the aeration tank or the second denitrification tank to a first denitrification tank in a reducing treatment applied state. CONSTITUTION:Excretion supplied from pretreatment equipment 1 to a first denitrification tank 2 is recirculated and flowed over the first denitrification tank 2 and a nitration tank 5 by flowlines 3, 4 in an activated sludge contained state and an ammonical nitrogen component is oxidized to NO2 or NO3 which is then removed while reduced to N2. Next, the treated water from the nitration tank 5 is supplied to a second denitrification tank 6 and NO2 or NO3 remaining in the treated water is reduced while the treated water from the second denitrification tank 6 is further supplied to an aeration tank 7 to attain to lower BOD of treated water and degassing. The treated water from the aeration tank 7 is supplied to the first denitrification tank 2 by a flowline 8, and NO2 and NO3 generated by over-aeration are removed while reduced to N2.
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