| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently execute both biological treatment of a sewage and separation of an activated sludge. SOLUTION: The liq. 13 in the nitrificating tank is kept within a previously set suitable viscosity range by measuring a viscosity of a liq. 13 in a nitrificating tank and regulating a draw rate of the sludge 10. In this way, a sticking.depositing of the sludge to a membrane surface of a membrane separation device 14 is hardly caused and also a clogging due to the sludge is hardly caused at an air diffuser 17 supplying a membrane surface washing flow since the liq. 13 in the nitrificating tank is kept in a state good in fluidity, and the liq. 13 in the nitrificating tank is filtered efficiently with the membrane separation device 14. When the suitable viscosity range satisfying a sludge conc. range suitable to the biological treatment is set, the biological treatment is executed efficiently.</p> |
