| 摘要 |
An embodiment of the present invention includes: an electrodialyzer 14 that electrodialyzes pretreated water 13; an evaporator 16 that evaporates concentrated brine 15 that is dialyzed by the electrodialyzer 14; a dryer 19 that produces salt 18 by drying condensed water 17 supplied from the evaporator 16; a reverse osmosis membrane apparatus 25 having a reverse osmosis (RO) membrane 25a that produces fresh water that is permeated water 24 obtained by removing a salt content from diluted brine to which acid is added; a recycle line that brings a part of salt-enriched membrane separation concentrated water 26 back to the rear flow side of a pretreatment apparatus 12; a water discharge line that discharges the remained concentrated water into a sea area; and a control apparatus 31 that controls to adjust the ratio between the discharging amount of the discharging membrane separation concentrated water to be discharged into a sea area and the supplying amount of supplying seawater. A pH is set to be equal to or less than 7.3 by adding acid 21. The salt 18 is obtained from the dryer 19, and produced water (fresh water) 29 is obtained by combining evaporated water 28 supplied from the evaporator 16 with the permeated water 24 supplied from the reverse osmosis membrane apparatus 25. |
