You can know that the importance of ultra-pure water equipment is very important to industry and commerce, such as: semiconductor manufacturing and pharmaceutical industry. Previously, pure water for industrial use was obtained by ion exchange. However, membrane systems and membrane processes are becoming increasingly popular as alternatives to pretreatment processes or ion exchange systems. Membrane systems such as electro-desalination processes (EDI) can clean minerals and work continuously. Moreover, the membrane treatment process is much simpler than the ion exchange system, and does not require acid, alkali regeneration and waste water neutralization. EDI processing is one of the fastest growing businesses in the membrane processing process. EDI is a non-reverse electrodialysis (ED) with a special sink filled with a mixed bed ion exchange resin. EDI is mainly used for the total solid dissolved amount (TDS) of 1-20mg / L of the water source made 8-17 megohm purified water.