This method has significant advantages in comparison with other demineralization methods: lower power consumption, simple design, assembly and operation, small dimensions, etc.
As the result of reverse osmosis, water and dissolved substances are separated at molecular level, thus almost demineralized water is accumulated on one side of membrane and all impurities are on the other side thereof.
Therefore, water with initial salt content of 3000 mg/l and more may be demineralized at reverse osmosis stage one to 10–200 mg/l.
High-selective membranes with working pressure 40-60 bars are used for sea water demineralization. Reverse osmosis membrane performance and permeate output are lower and, hence, they require more power consumption.
Composite roll-type polyamide membranes and acetate-cellulose membranes have been widely used in reverse osmosis processes.
Nanofiltration is used for brackish water demineralization with the use of membrane elements characterized be lower selective ability (50-80%).
Membrane element bodies are made of epoxy resin and fiberglass and stainless steel.