Reverse osmosis is the most precise membrane liquid separation technology. It can block all soluble salts and organic matter with molecular weight greater than 100, but it allows water molecules to pass through. The desalination rate of cellulose acetate membrane is generally greater than 95%, and the desalination rate of composite membrane is generally greater than 98%.They are widely used in seawater and brackish water desalination, boiler feed water, industrial pure water and electronic level preparation, drinking pure water production, waste water treatment and other special separation process. When the raw water contains high salinity (TDS > 500 mg/L),  reverse osmosis in front of the ion exchange can greatly reduce the load of ion exchange equipment, lower operating costs and wastewater emissions. At the same time, it could save a lot of regenerative acid and alkali, and reduce the pollution to the environment.

System

The water supply of the reverse osmosis device (Fig. 1) requires a pollution index SDI < 5. In order to ensure that the reverse osmosis membrane element is not fouled and blocked, the water supply passes through a security filter of 5μm filter element, and then is pressurized to the required working pressure by a high pressure pump.

The pressed water enters the reverse osmosis pressure vessel, which is equipped with one or various reverse osmosis membrane elements. The permeated water after passing through the membrane is the produced water that has been desalted, and the other part of concentrated water is discharged from the vessel.

Characteristics

Due to the different water quality, temperature and quantity, the membrane type, specification, quantity, arrangement, operation pressure and whether to add chemicals will be different for each set of reverse osmosis device, so the reverse osmosis device will determine its scale according to the specific situation.