Seawater desalination technology is used for fresh water production, which is for providing drinking water and agricultural water mainly.The process of extracting fresh water from seawater is desalination. The seawater desalina- tion methods include seawater freezing.electrodialysis, distillation, reverse osmosis and ammonium carbonate ion exchange. At present, the reverse osmosis membrane method and the distillation method are the mainstream in the market.

Raw water conductivity more than 500μs/cm, purified water conductivi- ty 1-10μs/cm.

One staqe reverse osmosis is suitable for the raw water with conductivity less than 500μs/cm and conductivity output water is 1-10μs/cm.