Oakham WRC (2026)
Oakham WRC tertiary sand filter installation nears completion - Courtesy of @one Alliance
Oakham is a market town at the centre of Rutland, surrounded by a largely rural catchment and closely connected to Rutland Water, one of the largest artificial reservoirs in Europe and a nationally protected Site of Special Scientific Interest (SSSI). Given the ecological importance of this waterbody, maintaining high water quality is critical to protecting local biodiversity, recreation and the long-term environmental health of the region. Increasing pressure on sensitive receiving waters has driven a renewed regulatory focus on nutrient control. In response, the Environment Agency has called for enhanced nitrogen removal and the generation of robust, real-world performance data to inform AMP9 planning and future regulatory standards. Due to its direct discharge to Rutland Water, Oakham Water Recycling Centre (WRC) was identified as a strategically important trial location.
Background
Anglian Water appointed the @one Alliance to deliver a full‑scale nitrogen removal trial at Oakham, designed to generate the robust evidence needed to shape future nutrient management strategies across the sector. This trial represents one of the most significant nitrogen removal studies undertaken in the region in recent years.
With new tertiary treatment processes, carbon dosing systems, infrastructure upgrades and enhanced analytical capability now fully installed, Oakham WRC is ready to begin delivering the insights required to inform future Total Nitrogen Technology Allowable Limits (TALs) and long‑term investment decisions.
By February 2026, the scheme had progressed into its final stages, following almost two years of design, construction, commissioning and close collaboration between Anglian Water, the @one Alliance and key supply‑chain partners. Once fully commissioned, the site will enter a year‑long monitoring programme designed to generate the critical performance data needed to support national decision‑making for the next asset management period.
3D model of Oakham WRC – Courtesy of @one Alliance
The drivers behind the Oakham WRC nitrogen trials
Following the sector-wide focus on phosphorus removal during AMP6/7, nitrogen has emerged as the next major regulatory priority. As environmental standards tighten and pressures on sensitive waterbodies increase, the water industry requires the same level of evidence, clarity and proven solutions for nitrogen removal.
The Environment Agency selected Oakham WRC as a strategic trial site due to its direct influence on Rutland Water, a highly sensitive SSSI where reductions in nutrient loading can deliver immediate and long-term ecological benefits. Any improvement in nitrogen performance at Oakham directly supports the protection of this nationally important asset and its wider catchment.
The scheme therefore addresses both immediate environmental protection requirements and the longer-term need to develop an evidence base that will inform regulatory and investment decisions across the UK water sector.
The solution
The Oakham WRC Nitrogen Removal Trial is centred on the installation and operation of a full-scale tertiary de-nitrifying sand filter system with carbon dosing, designed to remove total nitrogen from final effluent prior to discharge to Rutland Water.
This configuration enables biological denitrification to be trialled under real operating conditions, generating robust and transferable performance data to support future regulatory and investment decisions.
To minimise safety and regulatory risk, acetic acid was selected as the carbon source in place of methanol, avoiding the creation of a DSEAR-rated zone while maintaining effective denitrification performance. This approach, already proven elsewhere in the Anglian Water network, provides the industry with a practical and lower-risk carbon dosing solution that can be readily adopted at other sites.
The scheme includes the construction of concrete foundations for dosing systems and treatment kiosks, installation of a 30m3 dosing package from Lintott Control Systems Ltd, multiple control and monitoring kiosks, and new potable water infrastructure across the site.
Preparing the concrete foundations – Courtesy of @one Alliance
A new wet well and pumping station, DN250 auto-infeed strainer, static in-line mixer and carbon dosing arrangement have been installed to support consistent and controlled treatment performance.
Four DynaSand tertiary sand filters from Nordic Water (via Jacopa), housed within a dedicated kiosk, form the core of the nitrogen removal process.
Additional works include access road modifications, cross-site electrical ducting and new power connections, surface water drainage upgrades, and the installation of emergency safety facilities such as washdown points, showers and eyewash stations.
Enhanced sampling points and continuous Hach analysers for ammonia, nitrate and total nitrogen provide real-time performance monitoring, enabling detailed analysis throughout the trial period.
Oakham Nitrogen Removal Trials: Supply chain – key participants
The successful delivery of the Oakham WRC Nitrogen Removal Trial has relied on close collaboration across a wide range of technical and supply-chain partners.
- Project delivery: @one Alliance
- Principal contractor: MWH Treatment
- Civil works: DLO (@one Alliance Direct Labour)
- Dosing package & associated infrastructure: Lintott Control Systems Ltd
- Nordic Water DynaSand tertiary sand filters: Jacopa Ltd
- Mechanical & electrical installations: AVRS Systems Ltd
- Gorman-Rupp pump supply: Hydromarque Ltd
- Static mixers: Statiflo International Ltd
- Control systems: TES Group
- Continuous nitrate, ammonia & total nitrogen instrumentation: Hach
- Emergency shower facilities: Hughes Safety Showers Ltd
- Generators: Stuart Power Ltd
- Chemical storage tanks: Forbes Technologies Ltd
- Crane hire: Ainscough Crane Hire
(left) DynaSand filters arriving at Oakham WRC and (right) installation of the first DynaSand filter – Courtesy of @one Alliance
Commissioning & trials
Commissioning is scheduled for completion by March 2026, with the trial running from April 2026 to March 2027. Interim reporting will be aligned to the N-TAL Technical Specification, with a final report due in May 2027.
During this period, Anglian Water operational teams will oversee performance monitoring, data analysis and reporting, ensuring that findings are robust, transparent and suitable for national application.
While delivered as a trial, the scheme provides immediate and long-term benefits. The treatment assets will reduce nitrogen loading to Rutland Water, one of the UK’s most sensitive and valued freshwater environments, supporting its ecological health both during and beyond the trial period where performance improvements are demonstrated.
Lessons learned
The project mirrors the approach taken during the AMP6 National Phosphorus Trials, generating high-quality evidence under seasonal and hydraulic variability.
The data collected will benchmark acetic acid dosing, assess operational complexity, energy use and resilience, and directly inform Total Nitrogen Technology Allowable Limits and AMP9 planning across the sector.
In parallel, the scheme enhances understanding of integrated nutrient management by exploring how nitrogen and phosphorus treatment processes interact. With future phosphorus obligations already anticipated, this insight supports more efficient long-term planning and coordinated investment strategies.
The installation of new pumps, kiosks, mixers, analysers and control systems improves site resilience and operational flexibility, delivering lasting value regardless of future nitrogen compliance requirements.
Collectively, the project strengthens collaboration between Anglian Water, the Environment Agency, operational teams, suppliers and the @one Alliance, ensuring that future nitrogen standards are underpinned by verified, shared and evidence-based learning.
DynaSand filter installation nearing completion – access stairs being lowered into place – Courtesy of @one Alliance
Conclusion
As Oakham WRC Nitrogen Removal Trial enters the final stages of commissioning, the site is now positioned to support one of the most influential nitrogen removal trials in the UK water industry.
The integration of advanced tertiary treatment, acetic acid carbon dosing, enhanced monitoring and robust process control provides a strong platform for generating the evidence required to inform future regulation and investment.
Oakham WRC has become a demonstrator for innovation, collaboration and evidence-led environmental improvement, helping to shape a cleaner, more resilient future for both the region and the wider water sector.
