The United States ge-edi module mk-3 adopts the concentrated water circulation system technology. The main effect of adding salt in the concentrated water chamber is to reduce the chance of Ca2 + & Mg2 + carrying current in the concentrated water chamber, reduce the Ca2 + & Mg2 + flow flux and reduce the scaling rate; The secondary effect is to increase the ionic strength of concentrated water chamber, increase the dissolution of scale and reduce the chance of scale formation. Therefore, it has the characteristics of high water yield, stable water quality, strong performance controllability and low energy consumption.