All naturally occurring water contains dissolved mineral salts. While in solution, these salts separate into positively charged cations and negatively charged anions. Through the process of ion exchange, demineralization can significantly reduce the levels of these ions, thereby lowering the conductivity.
The process begins when raw water is passed through cation exchange resin. The cation resin is in the hydrogen form (H+) and exchanges all the positively charged ions for hydrogen, thus converting all the impurities in the water into acids.
The acidic effluent water from the cation exchange is then passed through anion exchange resin. The anion resin is in the hydroxyl form (OH-) and exchanges all the negatively charged ions into the hydroxyl form, completing the conversion of all impurities into water (H+ + OH- --> H2O), thus providing pure demineralized water.
Dual bed demineralizers use separate tanks; one containing cation resin, the other containing anion resin. A weak base dual-bed demineralizer produces water with a resistance of approximately 50 kOHM/cm, and strong base dual-bed units produces water with a resistance of about 200 kOHM/cm.
Mixed bed demineralizers utilize a single vessel, to thoroughly mix both the cation and anion resins. The mixed resin configuration produces a much higher water quality than a conventional dual-bed system. In fact, our typical mixed-bed demineralizers are designed to produce water with greater than 18 megOHM/cm resistance.  

RO well water desalination drinking plant

First stage pretreatment.(Quartz Sand filter)
The use of multi-medium quartz sand filters, main purpose is to remove the water contains sediment, manganese, rust, colloid material, mechanical impurities, suspended solids and other particles in the above 20UM of substances hazardous to health. The effluent turbidity is less than 0.5NTU, CODMN less than 1.5mg / L, iron content of less than 0.05mg / L, SDI less than or equal to 5. Water filter is a kind of "physical - chemical" process, the water through granular materials when isolated filter water impurities and colloidal suspensions. Filter is an effective water purification and treatment of the main process in the preparation of pure water is an indispensable process.

Second stage pretreatment (Carbon filter)
Activated carbon filters used to remove the pigment in the water, smell, a large number of chemical and biological organisms, reducing the residual value of water and pesticide pollution and other harmful pollutants.
The structure of activated carbon filters and quartz sand filters, the difference is placed inside the strong adsorption capacity of activated carbon for removal by the quartz sand filter without the filter out organic material, adsorption of residual chlorine in the water, using water more than less than or equal to chlorine 0.1ML/M3, SDI less than or equal to 4, are strong oxidants chlorine, there are various types of membrane damage, in particular, reverse osmosis membranes are more sensitive to chlorine. In addition, the activation process, the surface of activated carbon to form non-crystalline parts of some oxygen-containing functional groups, these functional groups can have a chemical adsorption of activated carbon catalytic oxidation of bad news, to restore the performance, can effectively remove a number of metal ions in water.
Third stage pretreatment (Resin softener)
Cationic resin used for water softening, primarily to remove hardness of water. The hardness of water is a major calcium (Ca2 +), magnesium (Mg2 +) ion composition, when containing the raw water hardness ions through the resin layer, the water of the Ca2 +, Mg2 + was exchanged resin adsorption, and other objects at the same time the quality of the release of sodium Na + ions flow from the softener in the water is removed from the softened water hardness ions. So as to effectively prevent the reverse osmosis membrane fouling.System can automatically recoil, and so is red.

Forth stage( RO system )
Using reverse osmosis technology for desalination, reverse osmosis membrane was only 0.001 micron pore size, can be harmful to remove dissolved solids and bacteria, viruses, etc., desalination rate of more than 99.6 percent, in line with national standards to produce pure water, the host section contains the security filter, high-pressure pump and reverse osmosis membrane, security filters for the fourth grade and above pre-treatment systems, high-pressure pump is the host of one of the core equipment for the reverse osmosis membrane elements to provide sufficient pressure to overcome the penetration resistance to pressure and run to meet the needs of a device to achieve the rated water.

RO well water desalination drinking plant