Various commercially available water systems are a combination of one to two kinds of purification technology to remove contaminants in the water. Because of different purification methods has different advantages and disadvantages, for contaminants of the type and quantity desired has its ability to remove the restrictions, the resulting purified water quality will vary.
     For example, "ion exchange resin", having excellent properties remove inorganics, in the initial use, the water quality can be achieved degree 10MΩ.cm above, but as to you saturated, gradual deterioration of water quality occurs. In addition, the organic matter in water, suspended particles and micro-organisms often carry a charge, and the non-specific adsorption of forming the barrier film on the surface of the anion exchange resin would make removal performance resin further deteriorates.
When using the "distillation", due to the evaporation of pollutants together with close boiling water vapor and pollutants in the water into distilled water; it may be contaminated when purified from the environment (air, container). In addition, distilled water storage containers microbial problems always exist, we must carry out regular maintenance work.
     Distillation and ion exchange columns sometimes together purified water. In the previous stage distillation technology to obtain higher resistivity of pure water, but it can not avoid the change in the water quality of the ion exchange resin caused disadvantages and increased microbial. If the follow-up stage distillation technology, a small number of microorganisms, water quality more stable, but has changed the removal efficiency of inorganic low.
     Based on the above needs, the ability to use a reverse osmosis membrane to remove water quality purification method to be more widely used. Most of the reverse osmosis membrane for the removal of different types of pollutants in water are quite good, can be significantly less subsequent purification in line, long-time stable removal capability of the system to maintain. However, the reverse osmosis membrane removal capacity depends on the amount of water in the conductive material, that is, out of the purified water as the water quality is affected by changes in the water quality of tap water (geographical impact, seasonal variation, etc.) . Therefore, reverse osmosis membranes are also used alone to refined method of high purity water quality at a later stage in the purification process and ion exchange resin combination. However, prolonged use, there would be some problems, such as changes in water quality associated with the ion exchange resin adsorption capacity reduced due to microbial reproduction.
     Recently, with EDI continuous deionization device, can effectively remove the water ions "RO-EDI way water plant" has been widely used up at a later stage reverse osmosis membrane. This is the highest of various water systems pollutant removal capacity, reverse osmosis water quality of the most reliable way.