METHOD FOR REMOVING BORON FROM WATER TO BE TREATED, BORON REMOVAL SYSTEM, ULTRAPURE WATER PRODUCTION SYSTEM, AND METHOD FOR MEASURING BORON CONCENTRATION

摘要

Provided is a method for removing boron from water to be treated, the method including: a step for subjecting the water to be treated to a reverse osmosis membrane treatment; a step for subjecting at least a portion of permeated water after the reverse osmosis membrane treatment to a step for removing cations; and a step for measuring the boron concentration in the permeated water after the process for removing the cations, wherein at least one among the following (a)-(e) is controlled on the basis of the measured value of the boron concentration: (a) the recovery rate of the water being treated in the reverse osmosis membrane treatment; (b) the temperature of the water to be treated; (c) the pH of the water to be treated; (d) the supply pressure of the water to be treated, which is applied to the reverse osmosis membrane of the reverse osmosis membrane treatment; and (e) the replacement timing of the reverse osmosis membrane used for the reverse osmosis membrane treatment.