Poppy Hill WRC (2026)
The new Poppy Hill WRC stormwater storage tank - Courtesy of @one Alliance
Located in Bedfordshire, Poppy Hill Water Recycling Centre (WRC) provides an essential wastewater treatment service for the surrounding communities, receiving and treating flows before safely returning treated water back into the environment. Across the East of England, wastewater infrastructure faces increasing challenges from population growth, changing rainfall patterns and more frequent periods of intense weather. During heavy rainfall events, additional surface water entering the network can significantly increase flows arriving at treatment works. Storm storage plays a vital role in managing these peaks by temporarily holding excess flows until they can be safely treated.
Background
As part of Anglian Water’s AMP8 investment programme, the Anglian Water’s @one Alliance is delivering a major storm storage upgrade at Poppy Hill WRC to improve the site’s ability to manage increased flows and reduce the environmental impact of storm overflow operation.
The project brings together civil, mechanical, electrical and process engineering disciplines to deliver a resilient solution that improves environmental performance while supporting the long-term operational capability of the treatment works.
New tank roof access – Courtesy of @one Alliance
The issue
Stormwater storage tanks are a critical part of wastewater treatment infrastructure, providing temporary storage when incoming flows exceed the capacity of the treatment process during periods of heavy rainfall.
At Poppy Hill WRC, existing stormwater storage capacity was assessed against updated Environment Agency requirements as part of the AMP8 regulatory programme. The assessment identified that the site required additional storage capacity to meet the required total working volume.
The existing site provided approximately 984m3 of storm storage, while hydraulic modelling determined that 2,308m3 of total working storm capacity was necessary. This created a requirement for an additional 1,324m3 of storage to ensure the site could effectively manage increased flows during storm events; fulfilling the site’s AMP8 regulatory programme.
The additional storage capacity will strengthen the site’s resilience during periods of heavy rainfall and support the effective management of increased flows.
The challenge for the project team was to deliver additional storage capacity while ensuring the solution:
- Achieved Environment Agency compliance requirements.
- Integrated effectively with existing treatment infrastructure.
- Maintained operational continuity during construction.
- Provided a robust, low-maintenance asset with a long operational lifespan.
- Supported improved resilience against future climate pressures.
The solution needed to provide more than additional capacity; it needed to create a reliable and efficient storm management system that could continue supporting the site for decades.
New tank and DI pipework – Courtesy of @one Alliance
The solution
Following hydraulic assessment and detailed design development, the selected solution was the installation of a new first-fill above-ground glass-coated steel storm tank from Hayes GFS Ltd, providing approximately 1,324m³ of additional stormwater storage capacity.
The new tank, measuring approximately 17.07m in diameter and 7.07m high, has been designed to operate alongside the existing storm storage infrastructure, increasing the total working storm storage capacity at Poppy Hill Water Recycling Centre from 984m3 to approximately 2,308m3. The glass-coated steel construction provides a durable and corrosion-resistant solution designed for long-term operational use. The prefabricated modular approach also supports improved quality control, reduced on-site construction activity and a more efficient installation process.
The new asset has been integrated into the existing stormwater management system, with the existing DN300 inlet pipework diverted to feed the new storm tank. The tank will be pump-fed using the existing Gorman Rupp T10 storm pumps, with stored stormwater returned through a new gravity return system incorporating a DN150 actuated valve. A new bellmouth overflow connection between the new and existing storm tanks enables both assets to operate together, maximising available hydraulic capacity during storm events.
Supporting infrastructure works include a new ultrasonic level monitoring system, actuated LCP, approximately 150m of new cable installation and a Type 1 footpath around the tank to support future inspection, maintenance and tanker access.
The scheme also includes a Xylem Water Solutions mixer jet automatic cleaning system, improving operational efficiency and reducing future maintenance requirements. The system uses stored stormwater to create an automated cleaning cycle, circulating flows through jet nozzles to remove settled material from the tank floor. This reduces the need for manual cleaning and confined space access, improves health and safety, enables faster return of the tank to service and supports improved long-term asset reliability.
New tank and access steelwork – Courtesy of @one Alliance
The project is being delivered within a live operational water recycling centre, requiring careful coordination to maintain existing treatment processes throughout construction. The delivery approach combines civil engineering activities with modular construction methods, with the glass-coated steel tank manufactured off-site before assembly at Poppy Hill WRC.
Multiple disciplines have been coordinated throughout delivery, including civil works, mechanical installation, electrical infrastructure, control systems, process integration and commissioning. Detailed sequencing has ensured existing storm storage capacity remains available during construction, maintaining operational resilience while the upgrade is delivered.
The completed scheme will improve environmental performance by providing additional storage capacity to reduce the likelihood of storm overflow operation during periods of high rainfall. By retaining greater volumes of stormwater within the treatment system until capacity becomes available, the project supports improved protection of the receiving environment and greater compliance reliability.
The increased storage capacity also strengthens resilience against future rainfall pressures, helping future-proof the site against changing weather patterns. By integrating the new tank with existing infrastructure, the project maximises the value of current assets while avoiding unnecessary redevelopment.
The combination of increased hydraulic capacity, durable materials, modular construction and automated cleaning technology provides a long-term solution that improves operational reliability, reduces maintenance requirements and supports Anglian Water’s wider environmental objectives.
DI pipework – Courtesy of @one Alliance
Poppy Hill Stormwater Storage: Supply chain – key participants
The Poppy Hill Storm Storage Upgrade is being delivered through the collaborative @one Alliance model, bringing together expertise from across engineering, construction and operational teams.
The project required key collaboration between:
- Project delivery: @one Alliance
- Principal contractor: Barhale
- Glass-coated steel storm storage tank: Hayes GFS Ltd
- EICA & mechanical partner: AVRS Systems Ltd
- Panel & telemetry outstation: TES Group
- Coring subcontractor: Specialist Cutting Services (SCS) Ltd
- Tank cleaning system: Xylem Water Solutions
- Valves: AVK UK Ltd
- Pipe & fittings supplier/fabricator: FT Ductile Ltd
- Direct delivery plant, labour & fuel: DLO
Working together across the supply chain has enabled the project team to develop a solution that delivers long-term environmental and operational benefits while maintaining safe and efficient construction.
Conclusion
The Poppy Hill Water Recycling Centre Stormwater Storage Upgrade Project represents a significant investment in strengthening wastewater infrastructure resilience across Bedfordshire and supporting the long-term environmental performance of the site.
The new stormwater storage tank will increase the site’s total working storage capacity to 2,308m³, enabling the treatment works to better manage peak hydraulic flows during periods of heavy rainfall, helping to meet Environment Agency requirements while significantly reducing the frequency and duration of storm overflow operation.
Project nearing completion – Courtesy of @one Alliance
Throughout the programme, the project team has successfully integrated new infrastructure within a live operational environment, ensuring the continued performance of the water recycling centre while delivering a complex civil and mechanical installation.
The scheme also incorporates a range of modern engineering solutions designed to enhance operational efficiency, reliability and asset longevity. These include intelligent process integration, automated cleaning systems that minimise maintenance requirements, and robust construction methods capable of withstanding the demanding conditions associated with wastewater treatment operations.
The project demonstrates how targeted investment in critical water infrastructure can deliver tangible environmental and operational benefits. By increasing resilience against extreme weather events, reducing the likelihood of storm overflows and improving overall network performance, the scheme contributes directly to the protection of local watercourses and the wider environment.
At the time of writing (August 2026), the £2m project is nearing completion with final commissioning and finishing activities now underway.
The new Poppy Hill WRC stormwater storage tank - Courtesy of @one Alliance
