| abstract |
The main purpose of the present invention is to provide a membrane separation method that inhibits the activity of microorganisms in the biofilm present on the reverse osmosis membrane, and at the same time can continue water treatment stably for a long time. The present invention can provide a membrane separation method that is a method of intermittently adding a combined chlorine agent containing an sulfamic acid compound to the treated water supplied to a reverse osmosis membrane separation device for membrane separation treatment, wherein the intermittent The addition is repeated: during the intermittent addition of water supply, the combined chlorine agent at a concentration that inhibits the activity of microorganisms in the biofilm is added to the water to be treated and then supplied to the reverse osmosis membrane separation device; and during the period of no added water supply, no combined chlorine is added The water supply is supplied to the reverse osmosis membrane separation device, and the time during the intermittent addition of water supply is 0.25 hour to 5 hours, and the time of the non-addition water supply period is 1 hour to 6 hours. |