A compact device used to feed salt water into reverse osmosis desalination systems can work in remote areas without electricity, according to the Fraunhofer Patent Centre for German Research (PST), which introduced this technology.
Most desalination systems work on the principle of RO, explained Edelgard Hund of PST in Munich, Germany. "Salt water is fed under pressure into a module and flows over a synthetic membrane. The polymer material allows water to pass through but rejects the passage of salt ions. Desalinated or fully deionised water flows out on the other side. As with distillation, this process requires the use of energy. With devices such as those manufactured by UT&S GmbH, the pressure necessary to force the salt water through the membrane "against its will" is generated using a water-jet pump.
Hund admits that this presumes that enough water with a minimum feed pressure is available. "Unfortunately, this is not always the case, particularly in countries with poorly developed infrastructures. Consequently, drinking water currently remains a prospect for the future because it's a question of cost for hotel operators. Tests are currently being performed on industrial dishwashers that operate without chemical water softeners. The new desalination devices are already being used in other industrial sectors, such as electroplating plants.