| 摘要 |
<p>PURPOSE:To reduce the thickness of a layer of matter to be filtered formed on the surface of a separation membrane by biologically treating waste water with bacteria to separate the same into a transmitted liquid and a holding liquid or a conc. liquid by the separation membrane and specifying the concn. of bacteria in waste water supplied to the separation membrane and the viscosity of waste water. CONSTITUTION:A purifying tank main body 1 is demarcated into a biological treatment chamber S1, a viscosity adjusting chamber S2 and a membrane treatment chamber S3 by partition walls 2, 3 and waste water is introduced into the biological treatment chamber S1 by an introducing pipe 4 and air is intermittently supplied to waste water from an air diffusion pipe 5 to purify waste water by aerobic treatment and anaerobic treatment. Next, waste water enters the viscosity adjusting chamber S2 and, after suspended component such as bacteria in the waste water is settled and separated, the waste water is sent into the membrane treatment chamber S3 to be separated into a conc. liquid and a transmitted liquid by a hollow yarn membrane module 6. At this time, the viscosity of the waste water is set to 30 cp or less and the concn. of bacteria in the waste water is set to 30kg/m<3> or less to thin the layer of matter to be filtered formed on the surface of a separation membrane.</p> |
