This process of reverse osmosis is not without its disadvantages, however, because the required energy consumption totals over 50% of the operational costs associated with desalination. It also means that water production is directly affected by fluctuating fossil energy prices. And of course, the environmental impact of using this energy and of the process itself has to be considered: reverse osmosis has a considerable negative impact on the marine environment. The salt content of the brine produced by this method of desalination and the waste chemical substances from the pre-treatment stage are harmful to the marine ecosystem.
The need to find a more efficient and environmentally friendly solution was clear. That’s why Nereid SA, which was established in 2010, has focused its efforts on developing a completely autonomous desalination system that uses renewable energy. This revolutionary approach combines a radial pump (developed by Nereid) integrated in a submersible reverse osmosis desalination unit and a land-based low-pressure distillation unit to treat the concentrate rejected by the system. By combining these two processes, Nereid is aiming to develop the first desalination system that does not release the rejected concentrate into the ocean and is therefore 100% environmentally sound. The system works equally well with solar or marine energy, or of course with power from the existing electrical grid.
But Nereid wants to go even further. Taking the company’s highly inventive concept as a starting point, its scientists are continuing to research ways of further increasing the efficiency of the pumps used to desalinate water. A new innovative process developed together with the University of Geneva should soon make it possible to produce drinking water without releasing any substances into the sea, by means of low-pressure, closed-circuit distillation at ambient temperature.
The distillation process would continue until the salt is crystallised, without any brine being released into the ocean.
One major advantage of this method is that the excess salt could be used for commercial purposes. A comprehensive new series of tests will be carried out at the École Polytechnique Fédérale de Lausanne in 2013, with the aim of moving forward with manufacture and commercialisation from 2014. This is a company with enormous commercial potential, therefore, which has been able to apply its inventive techniques to an ambitious and environmentally friendly project and is sure to have a significant impact on the lives of millions of people all over the world.
This innovative technology enables energy consumption to be decreased by 20% compared with the most recently developed techniques, reducing the final cost per cubic metre of drinking water produced. This cost saving is important, as it permits economic development in the coastal regions of developing countries by giving access to water and electricity where they were previously unavailable. As a result, development might also be possible in the fields of tourism, leisure or even agriculture (through the use of irrigation).
Sea nymph, daughter of Nereus and Doris in Greek mythology.
Decorative mosaic of a Nereid from 2 A.D. in the ancien Roman city of Daphne near Antioch (Turkey).