| 摘要 |
<p>PURPOSE:To increase the concn. of the microorganisms in an ultra-deep aeration tank and to obtain good treated water by mixing part of activated sludge again with the treated water produced by flotation of the activated sludge in the treated water discharged from the ultra-deep aeration tank and aerating said water again. CONSTITUTION:A flotation device 36 and an aeration device 38 are provided between an ultra-deep aeration tank 10 and a settling basin 14. The water to be treated and activated sludge supplied into the tank 10 pass through descending and ascending pipes 20, 22 and are returned into the tank 10. Part of the water to be treated flowing through the pipe 22 is fed into the device 36. Air is fed into the pipe 22 by a compressor 26, and the treated water is separated to treated water 44 contg. floating active carbon 42 and suspended solids of partly activated sludge in the device 36. The sludge 42 is returned to the tank 10, so that the tank 10 is maintained always at a high concn. of the activated sludge. The treated water 44 is fed to the tank 38, where the water is mixed with part of the sludge 42 and is again aerated. The activated sludge in the treated water is flocculated and is separated in the basin 14. Part of the sludge is returned to the tank 10 and the excess thereof is discharged. If the treated water is treated at good degrees and is sterilized, the releasing of said water is possible.</p> |
