Membrane Separation method comprises Supplying Water to treat a Membrane Separation device and add a chlorine intermittently Agent containing a compound Sulfamic Acid, where the period is 6 - without adding 120 hours and with addition of 0.5 to 40 hours, and Concentration On the agent of chlorine is 0.5 to 20 mg / L.

摘要

Clogging of membrane by slime adhesion is efficiently prevented and stable treatment can be carried out for a long period of time at a low cost by a small amount of chemicals without membrane deterioration and trihalomethane formation, even if applied to the water having a large number of viable cell counts and a harsh water quality by supplying water to be treated to a membrane separation apparatus 4, adding intermittently to the water to be treated a combined chlorine agent containing sulfamic compound, and repeating a non-addition feeding period in which water to be treated is supplied for 6-120 hours without addition of the combined chlorine agent, and an intermittent addition feeding period in which water to be treated is supplied for 0.5-40 hours under the addition of a combined chlorine agent at a biofilm exfoliating concentration in an early stage of biofilm formation during the non-addition feeding period.