| 摘要 |
PURPOSE:To attain effective decolorization with reduced consumption of ozone by the procedure in which effluent from digestion tank is diluted 5 fold or less and the amount of ozone to inject into an ozone-treatment tank is controlled in relation to the dilution ratio in the second stage and the target chromaticity of discharged water. CONSTITUTION:Temporarily treated night soil is digested in the digestion tank 3 and then diluted at a dilution ratio of 5 fold or less in the dilution tank 4. Then, it is sent through the aeration tank 6 and the sedimentation tank 7 into the ozone- treatment tank 8, where it is decolorized with zone, and then diluted in the dilution tank 11 and discharged to the outside. In the ozone-treatment tank 8, the amount of ozone to be injected is controlled so that the chromaticity Co of the ozone-treated water becomes Co=K2(C-Cw), where K2 is the dilution ratio in the dilution tank 11, Cw is the chromaticity of diluted water, and C is the target chromaticity of discharged water. With the method, interruption to decolorization with iron, manganese, etc. can be suppressed and effective ozone-decolorization can be attained. |
