Sea water desalination is regarded world-wide a very promising technology to provide water to the growing world population at a reasonable cost. Currently, the total desalination volume increases with 25 percent annually. Desalination will also become important for treating industrial waste water that contains more salt than is allowed by the new European framework directive water. This directive is to be implemented in the coming years.
TNO develops new technologies to enable low cost water desalination:
- Membrane distillation with Memstill; a technology that uses (low cost) waste heat.
- Membrane distillation with solar heat for decentralized production of potable water. Rural communities, resorts and remote islands may benefit from this idea.
- Electro-dialysis separates salt ions from water and enables the formation of acids and bases from salt solutions.
- High pressure reverse osmosis (HP-RO) uses pressures up to 180 bar for concentrating salts, resulting in brines up to 20% salt.
- Eutectic freezing, a special form of freeze crystallization yields pure water and salt crystals, allowing the disposal of solid salt.
Less scaling and fouling
Moreover, we offer a number of technologies that solve issues like scaling and fouling.
- Scaling, precipitation of salts from water, can be controlled by processes like MAC and FACT. These techniques are close to commercialization and offer a very compact solution to remove hardness or other components that can precipitate.
- Membrane fouling is drastically reduced by the Denutritor technology, that remove the feed stuff of micro-organisms, thus strongly reducing biofouling.
- Biofouling on membranes is counteracted through a coating with Ag / Cu nanoparticles, whereby the use time is increased.
Facilities and faculties
Furthermore, TNO has facilities for testing membrane performance and characteristics like retention, flux and fouling behaviour under both steady state and varying concentration conditions. Such tests are essential for membrane selection. Another ability of TNO is membrane autopsy. Biofouling, organic fouling and scaling can be demonstrated with electron microscopy (SEM, SEM-EXD) and confocal laser scanning microscopy.