Drinkable seawater a step closer, thanks to Ghent researchers

Summary

Mixing saltwater and fresh water could speed up the desalination process and cut the amount of energy needed in the process, a PhD student at UGent has discovered

Energy gain

Researchers at Ghent University have developed technology to desalinate seawater and at the same time generate energy. Until now, the desalination process has required a lot of energy, but this breakthrough brings sustainable drinking water production from seawater a step closer.

For her PhD, bio-engineer Marjolein Vanoppen examined how to reduce the energy consumption of traditional desalination. Getting a thousand litres of drinking water from seawater currently needs about as much energy as the average Belgian consumes each day.

To get salt from seawater, you generally need a membrane – a selective partition that lets water through while stopping salt. Driving the water through the membrane requires a lot of energy.

Vanoppen solved this problem by bringing together salt- and fresh water. “If salt- and fresh water come together, the salt wants to move towards the fresh water, a movement that generates energy, like when water streams down from a mountain and is caught in a turbine,” she explained.

She installed a membrane that first stops the water and lets the salt pass, which reduces the amount of energy needed to push the water through a membrane that stops the salt. “We gain energy in two ways, by both generating energy and lowering the amount of energy needed to produce drinking water,” she said.

More research is necessary before the technology can be applied on a large scale.