Why don’t we use desalination technology to provide drinking water? © iStock

Why don’t we use desalination technology to provide drinking water?

Water, water everywhere, but not a drop to drink - well, maybe a few here and there...

Asked by: Mike Glover, Doncaster

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Actually, desalination is used to provide drinking water. The largest desalinisation plant in the world is in the desert-bound realm of the United Arab Emirates. Closer to home, I’ve visited the impressive Llobregat plant just outside Barcelona. It serves 4.5 million people in the region with 200 million litres per day, a fifth of the total demand for drinking water. The recently opened Thames Water Desalination Planet in Beckton serves a million people in the Thames Estuary area.

Given that such plants are an effective way of providing clean water, why are they not more commonly used? The reverse osmosis process involved requires forcing salty water through a fine membrane. Dense brine is left behind and fresh water gets through. But the pressure needed is enormous and, so are the plant’s energy requirements and construction costs.


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