In the water exchange equipment or ion exchange or membrane desalination technology introduced: the use of ion exchange or membrane desalination to remove inorganic salts, etc., to improve the concentration of circulating cooling water. But according to the system used to increase the corresponding pretreatment. The above four kinds of depth treatment methods are selected according to the secondary treatment of sewage water quality and the depth of treatment after the use of sewage to decide. The adsorption oxidation and desalination treatment is used for higher-level users, such as boiler water, etc., the processing system is more complex, high investment. With the development of water treatment technology, especially the application of membrane treatment technology, it is one of the economically feasible methods to carry out desalting and deep treatment of reclaimed water.