Method for controlling slime in reverse osmosis membrane apparatus

A method for controlling slime in a reverse osmosis membrane apparatus, which is used in a reverse osmosis membrane apparatus and has a water-supplying step of supplying water to be treated to a reverse osmosis membrane, wherein

• the water-supplying step comprises a first water-supplying step in which a slime controlling agent X which contains 2,2-dibromo-3-nitrilopropionamide (DBNPA) and a slime controlling agent Y which contains at least one type selected from a group consisting of the following components (A) to (D) are added to water to be treated which has a pH of 10 or less, and the water to be treated which contains the slime controlling agent X and the slime controlling agent Y is supplied to the reverse osmosis membrane,
• Component (A):
• mixture of 5-chloro-2-methyl-4-isothiazolin-3-one (CI-MIT) and 2-methyl-4-isothiazolin-3-one (MIT)
• Component (B):
• chloramine compound
• Component (C):
• stabilized bromide
• Component (D):
• glutaraldehyde, and
• the first water-supplying step is run under at least one condition selected from a group consisting of the following operation conditions 1 to 3,
• Operation condition 1:
• an operation condition in which the water is separated into permeated water and concentrated water and respectively taken out, and the permeated water is discarded
• Operation condition 2:
• an operation condition in which the water is separated into permeated water and concentrated water and respectively taken out, and the permeated water is returned to raw water of the reverse osmosis membrane apparatus
• Operation condition 3:
• an operation condition in which the water is separated into permeated water and concentrated water and respectively taken out, and the permeated water and the concentrated water are returned to raw water of the reverse osmosis membrane apparatus.