Kier has secured four Thames Water contracts across Harpenden, Princes Risborough and Wisley sewage treatment works, with a combined value of nearly £65m, as part of Thames Water’s AMP8 investment programme.
The contracts cover main construction at Harpenden through Thames Water’s Go to Green Programme and at Princes Risborough through its Wastewater Asset Assurance Programme (WAAP), alongside an initial site-power upgrade at Wisley and design development for the next phase of improvements, which forms part of the Water Industry National Environment Programme (WINEP).
Together, the projects will increase treatment capacity, improve wastewater treatment and strengthen operational resilience across Thames Water’s network. Construction will be carefully planned around the continued operation of the existing treatment works. The work also supports Thames Water’s AMP8 environmental commitments and the Environment Act 2021 target to reduce phosphorus discharged from treated wastewater by 80%.
At Harpenden Sewage Treatment Works in Hertfordshire, the £53.7m upgrade will increase treatment capacity by more than 50%, supporting future growth through to 2036. The project will modernise key parts of the works, improve wastewater treatment and help Thames Water meet tighter environmental standards, while supporting the health of the River Lea.
At Princes Risborough Sewage Treatment Works in Buckinghamshire, the c.£7m programme will modernise stormwater pumping, flow management, electrical and control systems. The improvements will strengthen the resilience and reliable operation of the site.
At Wisley Sewage Treatment Works in Surrey, Kier is delivering a c.£1.7m initial power upgrade, including new site-power infrastructure to support current operations and future investment. Under a separate c.£2.6m design-services contract, Kier and design partner Binnies are developing the next phase of treatment improvements, which will support tighter environmental standards and the quality of treated water returned to the River Wey.
Andy Lingham, managing director for Water at Kier Infrastructure, said:
We have worked with Thames Water since AMP6, and these latest awards are another important step in our relationship. Working closely together means we can draw on Thames Water’s operational knowledge alongside the experience of our teams, designers and supply chain partners to plan the work carefully around each live site. That collaboration will remain important throughout delivery. Our focus is on carrying out the work safely and efficiently, minimising disruption and delivering improvements that support Thames Water’s customers and environmental commitments over the long term.
A Thames Water spokesperson said:
This major investment at Harpenden Sewage Treatment Works is an important step in improving river health and supporting future growth in the area. Alongside the work at Princes Risborough and Wisley, these projects form part of the significant investment we are making to upgrade our wastewater infrastructure, meet tighter environmental standards and build greater resilience for the communities we serve. Working closely with Kier, we will deliver the upgrades while maintaining operations at the sites and continuing to provide essential wastewater services for customers throughout the works.