The installation at the Bentley STW is part of a £6million upgrade to increase water capacity at the works and reduce the need for sewage discharges into the Wey during periods of heavy rainfall.
It’s also part of a greater bid to upgrade 250 wastewater sites around its region as the stricken firm bids to meet new government targets.
A phosphorus reduction scheme which aims to improve the quality of effluent released into the river following treatment is also part of the upgrade.
“We are pleased to have completed installing a new storm tank at our Bentley STW six months ahead of schedule,” said Kevin Brown, senior project manager at Thames Water.
“Further work is still taking place at our Bentley site. As part of the £6m upgrade, the phosphorus reduction scheme is expected to be completed in 2025 and will improve the quality of treated effluent.”
The tank is around four fifths the size of a tennis court and can hold an additional 252 cubic metres of wastewater, or two hours storage at the maximum flow rate.
Work on constructing the new and first storm tank at the Bentley plant began in November 2022 and was expected to take until March next year, only for installation to finish ahead of traditional rainfall season.
A similar upgrade at the Crondall STW has been completed with projects at the Selborne and Farnham Water Lane sites due to start within the next two years.
Two of the longest discharges in recent local history took place at the stations in late November with sewage being dumped into the Wey basin for 49 and 40 hours, respectively, from the STWs.