LONDON, England, Dec. 6, 2011 – With rainfall well below average in the “seriously water stressed” south of England, major utility Thames Water is preparing its unused desalination plant to help alleviate dwindling supplies.
The utility said so far this year only 468 mm of rain has fallen again the average of 739 mm and that it would need around 80% of its long-term average winter rainfall to avoid the likelihood of imposed water-use restrictions from regulator the Environment Agency.
Around 80% of the water supplied from the utility comes from rivers and 20% from underground boreholes.
Thames Water opened the country’s first major desalination plant last summer (see Water & Wastewater International magazine article) at an investment of £270 million. It said the facility would be able to provide 150,000 m3/day in the event of future water shortages.
At the time the utility received strong criticism for its choice of desalination over wastewater reuse, with experts citing the energy efficient argument of water reuse taking 1 kWh per cubic meter to process, compared to seawater treatment of 3 kWh per cubic meter (see WWi article).
Thames Water said using the Beckton desalination plant would be the first time is has been operated since testing and the official opening last year. The plant could supply one million people.
Other measures being taken by the utility include switching on extraction boreholes on the North London Artificial Recharge Scheme.
This is a confined aquifer which the company tops up with treated water all year round to provide an additional 180,000 m3/day of water for up to three months when needed (enough to supply over one million people). It can run for longer at a reduced rate. It is currently boosting supplies by 80,000 m3/day, but this is likely to increase over the coming weeks. It has only been used four times since it first came into use in 1995, according to the utility.