WATER TREATMENT METHOD

摘要

WATER TREATMENT METHOD 5 An object is to provide a water treatment apparatus and a water treatmentmethod that are capable of suppressing membrane fouling by use of a chlorine-containing chemical, while at the same time suppressing the increase of the chlorine-containing chemical to be used.The water treatment method membrane separates subject water by a reverse 10 osmosis membrane unit having a reverse osmosis membrane, comprising measuring the differential pressure on the non-permeate side of the reverse osmosis membrane unit, wherein when the measured value is less than a reference value, free residual chlorine-containing water to be treated having a free residual chlorine concentration within the range of >0.20 mg/L and <1.2 mg/L is membrane separated, and when the 15 measured value not less than the reference value, free residual chlorine-containing water to be treated having a free residual chlorine concentration within the range of 1.2-2 mg/L is membrane separated.[Fig. 1]20