| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for recovering activated sludge treated water where, by flocculation treatment, organic matters such as sugar and protein remaining in activated sludge treated water are efficiently removed, further, the remaining of flocculant components such as aluminum ions is prevented, the load on a separation membrane in the poststage can be reduced, and the clogging of a safety filter can be prevented. SOLUTION: As a first flocculation stage, in a first flocculation tank 1, an activated sludge treated water is added with an aluminum-based flocculant and a pH adjuster, and is subjected to flocculation treatment with the pH adjusted to 4.5 to 5.5; and, as a second flocculation stage, in a second flocculation tank 2, the first flocculation-treated liquid in the first flocculation tank 1 is added with a pH adjuster, and is subjected to flocculation treatment with the pH adjusted to 6.0 to 7.0. The second flocculation-treated liquid in the second flocculation tank is introduced into a membrane filtration apparatus 3, and is subjected to membrane filtration. The filtered liquid is introduced into an activated carbon treatment apparatus 4, and is subjected to activated carbon treatment. The treated liquid is introduced into a safety filter 5, and is further subjected to membrane filtration. The filtered liquid is introduced into an RO (Reverse Osmosis) membrane apparatus, and is subjected to RO membrane separation. The permeated water from the RO membrane is recovered as treated water. COPYRIGHT: (C)2006,JPO&NCIPI
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