Desalination solution for tidal Thames
Thames Water is planning to build Britain's first desalination plant on the river Thames near Barking in east London. Subject to planning permission the £200 million project is due to come on stream in 2007/2008 with construction work due to start around Christmas.The plant will convert salty water from the estuary into drinking water for London's population and will play a key role in guaranteeing supplies to customers during drought periods.
Thames Water claims the plant will have a maximum treatment capacity of 150 million litres of water a day, enough to supply 900,000 customers. The plant will save money and energy by taking water in on the ebb tide - when the water is going back toward the sea - so that the salt content is at its lowest level. A spokesperson for Thames Water told edie that this is roughly a quarter of the salinity of normal seawater.
This is then squeezed through an ultra-fine membrane four times to remove chlorine and sodium ions before being pumped to a treatment and storage reservoir in Woodford.
A pilot project has already been in successful operation for several months on a site adjacent to the proposed plant and Thames Water is confident of being granted planning permission for the main one.
A spokesperson told edie that the desalination plant would work in conjunction with the company's other operations, not instead of them. "Our main priority is to tackle problems of leakage in central London. This will be used to provide back up while we continue with pipe replacement work and ultimately will be crucial as the population increases over the next 10 years or so."
Due to problems such as leakage from old pipes, London has less water available than Madrid or Istanbul, with over 55% of available rainfall in the Thames Water region already being used for public supply.
Between 2005 and 2010, Thames Water is planning to relay and replace over 1,000 miles of ageing Victorian pipes, which have deteriorated due to corrosive shifting clay soils and heavy traffic in the capital.
By David Hopkins