| abstract |
Even in a permeation membrane having low chlorine resistance, contamination of the permeation membrane due to the growth of microorganisms can be prevented and membrane separation can be performed efficiently without causing a reduction in the removal rate or desalination rate due to deterioration of the permeation membrane. An anti-slime agent for membrane separation containing a chlorinated oxidant and a sulfamic acid compound, or a combined chlorinating agent comprising a chlorinated oxidant and a sulfamic acid compound. A membrane separation method in which a chlorinated oxidant and a sulfamic acid compound, or a combined chlorinated agent composed of a chlorinated oxidant and a sulfamic acid compound is present in the feed water or wash water of the membrane separation apparatus. Even when the pH changes due to fluctuations in raw water quality or accidents, the concentration of free chlorine in the water to be treated does not fluctuate greatly, so that a stable sterilization / growth suppression effect of microorganisms can be obtained. Even when using a permeable membrane made of a polyamide-based polymer with low chlorine resistance, the free chlorine concentration does not increase instantaneously, and oxidative deterioration of the permeable membrane can be avoided, Membrane separation can be performed efficiently. [Selection] Figure 1 |