The need for high-quality water significantly increased during the second half of the last century. An important problem is about to be solved at a near-affordable cost. The cost of desalinated water is decreasing.

Desalination of sea (or brackish) water has been practiced regularly for over 50 years and is a well-established means of water supply in many countries. It is now feasible, technically and economically, to produce large quantities of water of excellent quality from desalination processes.
Membrane processes, mainly Reverse Osmosis (RO), are currently the fastest growing techniques in water desalination. The RO uses dynamic pressure to overcome the osmotic pressure of the salt solution. With RO, salty water is subjected to high pressure and forced through a membrane, which results in the retention of the salt ions.

The main characteristic of the RO process is that the greater part of the generated pressure to feed the membranes is lost when the brine is returned to the sea. The selection of pumps must consider the specific operational aspects of the plant design; depending on the principle of pressure recovery selected (either via Pelton turbine or work/pressure exchangers), different pump needs arise. The performance and selection of optimum pumping equipment is paramount to reaching the best possible reliability and lowest operating cost in RO desalination plants. In all applications, the material selection for the pump and the wear parts contributes to a reliable long-time performance. Since 40 to 45 % of the pump energy is saved, respectively recovered in a direct manner, RO is an attractive solution for the operators of desalination plants.