The German engineering conglomerate Siemens believes it has found a way to desalinate water at a fraction of the cost of previous methods. Distillation and reverse osmosis are currently the two most commons methods, which cost 10kWh and 4kWh per cubic meter, respectively. By using a process called electrodialysis, in which seawater is pumped into a series of channels walled by membranes that have slightly different properties from those used in reverse osmosis, salt water can be desalinated at a cost of 1.8 kWh per cubic metre.
What’s the Big Idea?
Siemen’s desalination project has been funded by the Singapore government which, because of the water crisis the country faces, is feverishly looking for ways to provide its population with drinking water. The desalination plant that uses electrodialysis has been in operation in Singapore for six months and engineers hope they can further cut the amount of energy used to remove the sodium and chloride from ocean water. A cost-effective desalination process would allay many fears about geopolitical conflicts potentially sparked by future water shortages.