New desalination process uses 50% less energy

Fresh water reserves are shrinking as the climate changes and growing populations tap out existing freshwater reserves.

“In some areas renewable water reserves are in danger of dropping below the 500 cubic meters per person per year considered a minimum for a functioning society,” writes Scientific America in a recent article.

Desalination was possible, but current processes make it expensive. Siemens explains its different approach to the problem:

The project goal was to produce World Health Organization standard drinking water quality from seawater, at the same time cutting energy consumption by half compared to current technologies. Instead of using reverse osmosis, which requires high-pressure pumps to force water through semi-permeable membranes, the Siemens engineers turned to electrochemical desalination. The process combines Electrodialysis (ED) and Continuous Electrodeionization (CEDI), both applying an electric field to draw sodium and chloride ions across ion exchange membranes and out of the water. As the water itself does not have to pass through the membranes, the process can be run at low pressure, and hence low power consumption.

Image from Siemens showing a R&D engineer examining desalination prototype in Singapore