Thames opens first UK desalination plant

London is described as: “seriously water-stressed” by the Environment Agency, which means water demand could outstrip supply in a drought. The £270M Beckton plant will convert seawater and tidal water from the Thames into enough drinking water for 1M people.

The reverse-osmosis plant was opened by the Duke of Edinburgh today. Thames Water says it is the first plant ever to use four-stage reverse-osmosis process to create drinking water, which has a freshwater yield of 85%, a significant improvement on traditional two-stage processes which have a freshwater yield of just 50%.

Beckton will only take in water on the outgoing tide, when it is a third as salty as normal seawater and so requires less energy to treat it.

Thames Water’s Chief Executive, Martin Baggs, said: “People may wonder why we’re equipping ‘rainy’ London with a desalination plant, something more often associated with the Middle East, southern Europe or ocean-going liners.

“But the fact is, London isn’t as rainy as you might think - it gets about half as much rain as Sydney, and less than Dallas or Istanbul. Water is an increasingly precious resource that we can no longer take for granted.

“Our existing resources - from non-tidal rivers and groundwater - simply aren’t enough to match predicted demand in London. That’s why we’re tapping into the new and limitless resource of the tidal Thames, fed by the rolling oceans beyond, so we can ensure our 8.5 million customers have enough water in future in the event of a drought.

“The 2005/06 drought was too close for comfort, with only a very wet May saving the day, and we never want a repeat of that. It highlighted what we already knew: additional water sources are needed, as well as a lot more work on reducing leakage, to be sure we have sufficient supplies long-term.

“This new works is a major advance in desalination technology and in UK water resource management. Running it on biodiesel, derived from materials including used cooking oil, will also help us tread as lightly as possible on the environment, on which our core business depends.”