摘要 |
This invention relates to an apparatus and method for a multistage reverse osmosis separation which comprises reverse osmosis membrane module units (2,8) arranged at multistage with a booster pump (7) provided in the concentrate flow channel (4) between reverse osmosis membrane module units (2,8), wherein the total effective reverse osmosis membrane area of a module unit (8) is in the range of 20-80% of that of the preceding module unit (2). The object of this invention is to provide apparatus and separation method that produce low-concentration solution from high-concentration solution with a high recovery ratio, small energy requirements, and high stability. |