WATER TREATMENT SYSTEM

To provide a system of effectively suppressing biofouling, while preventing a generation of resistant bacteria, and suppressing a deterioration of a reverse osmosis membrane as much as possible.SOLUTION: There is provided a water treatment system 1, including: injection means 6, 7 for injecting a stabilizer and a bromine compound into a water supply W11; and a chemical concentration adjustment unit that switches a chemical concentration adjustment step in water supply performed by the chemical injection means, between a first chemical concentration adjustment step of injecting the stabilizer into the water supply W11, and a second chemical concentration adjustment step of injecting the chemical of the stabilizer and the bromine compound to the water supply W11.SELECTED DRAWING: Figure 1 【課題】耐性菌の発生を予防すると共に、逆浸透膜の膜劣化を極力抑えながら、効果的にバイオファウリングを抑制するシステムの提供。【解決手段】給水Ｗ１１に安定化剤、及び臭素化合物を薬注する薬注手段６，７と、薬注手段が実行する給水中の薬剤濃度調整工程を、給水Ｗ１１に安定化剤を薬注する第１の薬剤濃度調整工程と、給水Ｗ１１に安定化剤、及び臭素化合物を薬注する第２の薬剤濃度調整工程との間で切り替える薬剤濃度調整部と、を備える水処理システム１。【選択図】図１