| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that the lowering of flux caused by the deterioration or fouling (clogging) of a membrane is not avoided when membrane separation is adapted to the treatment of sewage and various cleaning means such as an aeration means or the like for applying cleaning operation to a filter membrane module from the lower part thereof is employed as a means for restoring the lowering of flux but it is difficult to perfectly restore the lowering of flux, and a method for taking out the filter membrane module from a membrane separation tank to wash the same with a chemical liquid is employed but, in such a case that the scale of the membrane separation tank is large, it is very difficult to take out the whole of the filter membrane module from the tank. SOLUTION: In a sewage filtering method wherein raw water is supplied into a reaction tank in which the filter membrane module is arranged and filtering pressure is applied to the interior of the filter membrane module immersed in raw water to perform filtration and ozone or ozone-containing gas is injected in the filter membrane module to backwash a membrane, the membrane is formed from a metal membrane and filtering pressure is set to 60-90 kPa.
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