Water treatment method and water treatment device

Abstract

The present invention pertains to a water treatment method in which raw water or water obtained by pretreating the raw water is supplied as supply water under pressure to a semi-permeable membrane module by a boost pump and the supply water is separated into concentrated water and permeated water, wherein the water treatment method is characterized in that a scale inhibitor is added to the supply water before a reduction agent is added to the supply water or within 0-60 seconds of the reduction agent being added to the supply water