Seawater Desalination by Reverse Osmosis

In reverse osmosis (RO), a semipermeable membrane acts as a molecular separator or filter removing the pure water ("permeate") from the saline feed stream by pressure driven transport. The process is today established in the desalination of brackish water, where bidding and selling plants of one million gpd* and more on the basis of specified water quality data is an accepted practice in the trade. The published performance record of some plants installed over the last five years is available as realistic evidence to back the warranties given by manufacturers. Research in seawater RO - supported to a large measure by the U.S. Department of the Interior (Office of Water Research and Technology)- has now reached the point where reverse osmosis is moving also in this field from the R&D phase into the commercial arena. Process Principles The phenomenon of natural osmosis takes place when adilute solution and a concentrated