Water & Wastewater Treatment Magazine
Issue link: https://read.utilityweek.co.uk/i/481381
Project focus: water resource management 22 | APRIL 2015 | WWT | www.wwtonline.co.uk • Innovations ● The qualities of the Lower Greensand aquifer mean treated water can be stored in a 'bubble' which retains its integrity and the water is still high quality when it is pumped out ● The operational trial uses two 250m-deep production bore- holes and a series of observation boreholes for hydrogeologists to model the aquifer's behaviour ● Water is pumped into the aquifer at a rate of 3 megalitres a day and out again at 5 megalitres a day need disinfection. There is 10 times more storage available underground in aquifers in the Thames Water region than there is above ground in reservoirs, and 70% of the Thames Valley's drinking water already comes from groundwater sources; so it is not hard to see why ASR has significant potential for Thames. Jones says that the utility has identified three possible similar projects in the Lower Greensand, a number which may increase as the team learns more about the aquifer. In the long term, there is also the prospect of investigating ASR in other aquifers such as the Cotswold Oolites. Other water companies in the UK to have investigated ASR include Yorkshire Water, Wessex Water and Severn Trent, although none have yet progressed as far with it as Thames. "The idea of ASR has become popular again, mainly because there's only a certain amount you can do with demand management to close the supply-demand gap," says Jones. "You could start looking at desalination or effluent reuse, but they are quite expensive. ASR can help you fill a reasonably modest sized gap in the supply-demand balance much more cost effectively. "ASR is a great innovative technique which helps us make best use of water resources while protecting the environment and giving us water supply resilience. It's a great thing for storing water for larger, more severe droughts that might very well be with us in an uncertain climate change future." Thames Water's ASR project has been shortlisted as a finalist in the 2015 Water Industry Achievement Awards: waterindustryachievementawards.info The rig for the borehole, which was drilled between September 2014 and January 2015 A series of observation boreholes are also needed as the schame is tested this year