| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technology which uses strongly acidic water generated from an electrolytic water generator for washing a reverse osmosis membrane, and sends and adds strongly alkaline water generated simultaneously from the electrolytic water generator to a branch passage as a membrane circulation system to remove boron by the reverse osmosis membrane, thereby reducing the boron concentration to a drinking water standard value or less. Ž<P>SOLUTION: The strongly alkaline water from the electrolytic water generator 31, flowing into the branch passage 28a through a strongly alkaline water passage is injected and mixed with pretreated seawater 25 flowing into the branch passage 28a without being discharged into a drainage 32, and the mixture is fed under pressure to the reverse osmosis membrane 29 by a pump 28. The pH of the seawater 25 pretreated by the strongly alkaline water is increased and adjusted to 9.0-9.5 to convert boron contained in the seawater to be treated into a form of borate ion. Particles of the size which can be filtered with the reverse osmosis membrane 29 are obtained by the conversion of boron into the form of borate ion, and the boron is removed by the reverse osmosis membrane 29. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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