The first type ：a deionized water purifier made using an anion exchange tree. Generally, after passage, the conductivity of the effluent drops below 10us / cm, after which the mixing bed can reach 1us / cm or less. Disadvantages of the water produced in this way are the very high operating costs, the complexity of the operation, the excess of particulate impurities, the emission of acids and alkalis on site and the requirements of environmental protection. There is no discharge of concentrated water compared to reverse osmosis equipment. In addition, it is easier to adjust the pH of the production water than in a reverse osmosis unit. Considering the above advantages and disadvantages, this equipment is rarely used.
The second type: pretreatment (ie, sand carbon filter + precision filter) + reverse osmosis + mixed bed process. Currently, this deionized water treatment method is used more often because the reverse osmosis investment cost is not high, more than 97% of water ions can be removed, and the remaining ions are removed by mixed bed exchange. Rate: about 0.06. This method is now common and the process is relatively stable.
Third type: Deionized water purification device made by two-stage reverse osmosis
The process is as follows: tap water → multimedia filter → activated carbon filter → water softener → intermediate water tank → low pressure pump → precision filter → primary reverse osmosis → pH adjustment → mixer → secondary reverse osmosis (reverse osmosis surface membrane Positive charge) → pure water tank → pure water pump → microporous filter → water point
Fourth type: Pretreatment uses a second reverse osmosis as a third method, except that EDI (electrodeionization system) is added to the continuous desalination membrane block. Compared with mixed beds, EDI does not use acid-base regenerated resin. , But with electrical regeneration. As a result, the entire process is completely pollution-free and the water quality of this deionized water system reaches more than 15 megaohms. However, this method has a high initial investment and lowers operating costs.
The process is as follows: tap water → multimedia filter → activated carbon filter → softener → intermediate water tank → low pressure pump → precision filter → primary reverse osmosis → pH adjustment → mixer → secondary reverse osmosis positive charge) → pure water tank → Pure water pump → Intermediate water tank → EDI water pump → EDI system → Microporous filter → Water point