| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size of a waste water treating device by adding an inorg. flocculating agent to water which is to be treated and is introduced into an aeration vessel, adding an amphoteric org. high-molecular flocculating agent thereto in the state of adjusting its pH value to a specific one and subjecting the water to a solid liquid sepn. by a separating member while subjecting the water to an aeration treatment. SOLUTION: The inorg. flocculating agent is added to the waste raw water to be treated to adjust its pH value to 5 to 8 before the water is transferred into the aeration vessel 1. While the amphoteric org. high-molecular flocculating agent is added to the waste water adjusted in the pH in the aeration vessel 12, the water-soluble components are decomposed by active sludge and the waste water is subjected to the solid liquid sepn. by a hollow fiber membrane module 14. The filtrate is released into rivers, etc. The sediment is thickened in a sludge thickening vessel and is then disposed by removing water therefrom with a dehydrating machine. The amphoteric org. high-molecular flocculating agent contains a carboxyl group or its salt as an anionic group. The cation equiv. Cv value of the amphoteric org. high-molecular flocculating agent is specified to 1.0 to 4.0meq/g, the anion equiv. value Av to 0.3 to 2.0meq/g and the Cv/Av ratio to 1.5 to 8.0. |
