While AQUALITY® processes will retain suspended solids, EXSEL® processes such as nano-filtration and reverse osmosis will retain dissolved solids.
The process of reverse osmosis is not the same as filtration. Filtration is the removal of particles by size exclusion, while in reverse osmosis such physical holes may not exist. It is more likely that water is able to diffuse through the membrane polymer by bonding between segments of the polymer's chemical structure.
The EXSEL® desalination process uses a pump and a semi-permeable membrane. The pump provides the driving force for the separation, while the semi-permeable membrane passes water in preference to the solute that is dissolved in the water. The majority of the solute is left behind to form a more concentrated stream. Since feed- and concentrate stream move tangentially to the membrane, the filtration principle is called cross-flow filtration.
- Seawater desalination
- Desalination of brackish water
- Production of highly purified process water
- Production of drinking water from any water source