WATER DESALINATION DEVICE, AND WATER DESALINATION METHOD

摘要

A desalination apparatus includes a first reverse osmosis membrane device 13 that removes a salt content from raw water supplied with predetermined pressure, a second reverse osmosis membrane device 15 that removes a salt content in first permeated water 12 from the first reverse osmosis membrane device 13, a first flow regulation valve 17 that regulates flow rate of first concentrated water 16 from the first reverse osmosis membrane device 13, a second flow regulation valve 19 that regulate flow rate of second concentrated water 18 from the second reverse osmosis membrane device 15, and a control device that measures a supply temperature of the raw water 11 by a thermometer 20, controls the first flow regulation valve 17 to maintain discharge amount of concentrated water constant, and controls the second flow regulation valve 19 to reduce a return amount of water so as to perform operation such that supply flow rate for the first reverse osmosis membrane device 13 is controlled to be lower than flow rate in summer in which a temperature is high, and predetermined product water recovery ratio is maintained to a predetermined amount.