Sodium, calcium, magnesium, chloride, nitrate, bicarbonate, water and other solutes in the general urban existence. The compound represented by the negatively charged anions and positively charged cationic composition. Pretreatment by reverse osmosis, more than 99% of the ions can be removed, but the former may also include other trace elements in water, dissolved gases (such as CO2) and some of the weak electrolyte (e.g., boron, silicon dioxide) in addition to these impurities in the industrial salt It must be removed. But the reverse osmosis process to remove these impurities are less effective, have to rely on other ways to do, the best way is the latest EDI devices. - EDI ultra-pure water equipment EDI equipment belonging to polishing water system, and more generally with the reverse osmosis (RO) with the use of the composition of the pretreatment, reverse osmosis, ultra-pure water treatment system EDI system, replacing the mix of traditional water treatment processes Ion exchange equipment. EDI means the water requirements for the resistivity of 0.025-0.5MΩ · cm, reverse osmosis unit fully meet the requirements. EDI apparatus can produce high resistivity 18MΩ · cm or more ultra-pure water. Guangzhou Tianshui EDI ultra-pure water equipment using EDI methods, the main process is as follows: Raw water → raw water pressure pump → → Multi-media filter activated carbon filter → → → precision filter water softener reverse osmosis machine → intermediate tank → intermediate Pump → EDI system → → water points micropore filter - EDI ultra-pure water equipment