| 摘要 |
PURPOSE:To reduce the area for installation, to simplify the control of operation, and to permit reutilization of treated water as water for miscellaneous use by installing an ultrafiltration apparatus for separating waste water into sludge and treated water to a slip stream side of an aeration tank for treating the waste water biologically with activated sludge. CONSTITUTION:An ultrafiltration apparatus 3 for separating waste water into sludge and treated water is installed to the slip stream side of an aeration tank for treating the waste water biologically with activated sludge. A vertical tubular module 28 consisting of ultrafiltration membrane is installed to the ultrafiltration apparatus 3, and solid particles 33 contained in the vertical tubular module 28 are kept in fluidized condition with a fluidizing velocity within a range above a fluidization initiating velocity and below a terminal velocity of particles for fluidization by the control of supplied flow rate of a liquid mixture. As a result, the installation area of the whole waste water treating apparatus is reduced. Further, carry-out of the activated sludge is retarded, and requirement for installing a flow rate controlling tank is eliminated. Thus, the operation of the apparatus is simplified. Moreover, since the treated water is utilizable as water for miscellaneous use, increased cost for waste water treatment is recovered.
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