| 摘要 |
A method for biological treatment of water containing organic matters is provided to improve a clogging prevention effect of a membrane and increase permeation flow rate of a membrane separation device by the addition of a flocculant. In a method for biological treatment of water containing organic matters, comprising introducing water containing organic matters into a biological treatment tank and mixing the water containing organic matters with activated sludge to treat biologically the water containing organic matters, and subjecting a mixed liquid of the water containing organic matters and the activated sludge to a membrane separation process, the method further comprises presenting an iron salt in the biological treatment tank such that a ratio of the concentration of the iron salt as iron to that of the activated sludge ranges from 10% to 45% by mass and adjusting a pH of the mixed liquid to a range of 5 to 6.5 at the same time. The method comprises adjusting an MLVSS(Mixed Liquor Volatile Suspended Solid)/MLSS(Mixed Liquor Suspended Solid) ratio as a ratio of organic suspended solids of the activated sludge to the concentration of the activated sludge to a range of 0.05 to 0.75. The mixed liquid is subjected to the membrane separation process by a submerged membrane module submerged into the biological treatment tank. The water containing organic matters is natural water, tap water, or recovered water. |
