| 摘要 |
<p>PURPOSE:To exhibit the maximum treating performance with a septic tank having an absolute minimum size by specifying a ratio of a day average residence time, defined by a ratio of a volume of a flow rate controlling part to a daily flow rate of waste water to the flow rate controlling part, to a membrane permeation flux of a separation membrane of a membrane separation device. CONSTITUTION:The septic tank 1 is divided into the flow rate controlling part S1 and a biological reaction chamber S2 with a partition 2 and an introducing pipe 3 of the waste water is provided at the flow rate controlling part S1. On the other hand, the membrane separation device 7 is disposed in the biological reaction chamber S2, and an aeration device 12 is disposed at downwards of the membrane separation device 7 and the membrane separation device 7 is provided with the separation membrane 8 such as a hollow fiber-like membrane. In this case, when a daily flow rate of the waste water to the flow rate controlling part S1 is denoted as (v) (m<3>/day) and a volume of the flow rate controlling part S1 V (m<3>), the ratio [R/J] of the day average residence time R (V/v) (day) of the waste water to the membrane permeation flux J (m<3>/m<2>.day) of the membrane separation device 7 is in a range of 0.02<=[R/J]<=60.</p> |
