Thames Water said that the Thames Gateway Water Treatment Works at Beckton in east London will provide London with a back-up supply to use in the event of a drought.
Powered by biodiesel largely made of used cooking oil, the £270m plant is the world’s first-ever four-stage reverse osmosis system, yielding a far more efficient 85%, whereas most reverse osmosis plants have one or two stages.
The plant 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, according to the water utility.
The company said that the new works is able to produce 150 Mld (million litres of water a day) when needed, enough to supply 400,000 homes (one million people).
The company further added its water will be blended with other supplies, so up to 580,000 properties in northeast London (1.4 million people) will potentially receive it in varying proportions.
Thames Water supplies its 8.5 million drinking water customers across London and the Thames Valley with 2,600 Mld.
