| 摘要 |
PROBLEM TO BE SOLVED: To provide a fresh water generating method using reverse osmotic separation by which the water generating cost is reduced and deterioration of water quality of fresh water is prevented. SOLUTION: In this fresh water generating method, at least two reverse osmosis membrane module unites 2, 4 containing reverse osmosis membrane elements provided by connecting in series, are provided and sea water is fed to the reverse osmosis membrane module unit at the initial stage, and also concentrated sea water obtained from the reverse osmosis membrane module unit 2 at the front stage is fed to the reverse osmosis membrane module unit 4 at the succeeding stage, and then permeated water is obtained from respective stages. In this case, while back pressure is applied to a permeated water side of the reverse osmosis membrane at the front stage, the concentrated sea water obtained from the front stage is raised in pressure by a turbocharger 8 provided between the preceding stage and the post stage, and then is fed to the post stage.
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