| 摘要 |
The primary side of a semipermeable membrane unit which is composed of one or a plurality of semipermeable membrane elements, and supplied with raw water to obtain permeant water and concentrated water, is fed a blocking-rate improver solution containing a blocking-rate improver. The feed pressure and/or permeant water flow rate is measured during feed of the blocking-rate improver solution, and on the basis of measured values, at least one action selected from modification of the permeant water flow rate during feed of the blocking-rate improver solution, modification of the concentration and/or the composition of the blocking-rate improver in the blocking-rate improver solution, halting of the feed of the blocking-rate improver solution, and modification of the temperature of the blocking-rate improver solution, is executed. |
