Supply Chain - Treatment Process Technologies - Membrane Bioreactor

In recent times Seagahan WTW has faced ongoing issues including:

Unaddressed, these deficiencies could pose risks to regulatory compliance, limit future growth capacity, and increase the potential for Cryptosporidium contamination.

The Seagahan WTW Treatability Improvements Project has implemented a series of targeted upgrades to enhance water quality, improve operational resilience and maintain compliance. Key interventions included:

These upgrades are informed by a treatability appraisal conducted by Arup, which identified critical shortfalls and recommended improvements to ensure the facility could meet current and future regulatory standards.

NI Water engaged Arup and Murphy DAWSON-WAM (MDWAM) early in the project through an Early Contractor Involvement (ECI) approach, fostering a collaborative environment that allowed the project to evolve efficiently. As Principal Contractor, Murphy DAWSON-WAM, supported by strong coordination across all parties, successfully delivered the project on time and within budget. Arup played a dual role, providing NEC Project Management and Supervision throughout the construction phase, while also leading design reviews and approvals. Their involvement extended to managing stakeholder engagement within NI Water and liaising with external bodies such as the Department for Infrastructure.

A key success factor was the strong working relationship developed with NI Water’s Operations, which enabled a clear understanding of practical operability challenges. This collaborative approach informed strategic decisions around infrastructure layout, including pump and panel positioning, freeing up space for storage and maximising the use of existing buildings. These efforts not only streamlined project delivery but also ensured the long-term resilience of water treatment at Seagahan WTW.

ECI with MDWAM and Arup enabled a collaborative and informed approach from the outset of the project. Arup provided up-front technical input through treatability studies, which were instrumental in shaping Business Case submissions and developing focused Basis of Design reports. This proactive engagement supported scope progression and ensured a robust design strategy. Throughout the process, NI Water stakeholders were actively involved in decision-making, fostering transparency and alignment across all phases of delivery.

As designs evolved, a number of design review workshops were held which involved the use of walkthrough models to highlight pinch points and process walk-throughs.

Preference was for the new soda ash storage silo to be located indoors, restricted space for which was determined in the existing GAC building. MDWAM introduced innovative methods, including a 3D scan of the existing GAC building, to validate the feasibility of initial design proposals and facilitate the reuse of existing storage space. The volume and design of the storage silo were influenced by these constraints. The 3D scanning of the existing GAC building was instigated in the absence of record drawings, with new equipment designed to fit head height constraints and roller door access for installation.

A key design decision identified during a design review meeting was the introduction of a structural steel mezzanine platform level to locate the new MCC as floor space was limited.

During the initial investigations, the team identified gaps in the existing information relating to original structures, highlighting the need for further exploration. In several instances, monitoring data was unavailable, so dosing pump and process design had to be guided by SCADA trend analysis where possible. Temporary instruments were also set up during ECI to capture critical analytical data that was otherwise missing. These proactive measures ensured that design decisions were grounded in accurate, site-specific information, ultimately enhancing the reliability and efficiency of the final solution.

The project was delivered within a live operational environment, requiring meticulous planning and coordination to ensure continuity of service and safety. Construction on site began in December 2023 and completion was at the beginning of July 2025. The works were sequenced to minimise disruption to ongoing treatment operations, with close collaboration between the design, construction, and operations teams throughout. A key inherent risk exists when interfacing with existing operational works, live instruments and electrical assets, and this collaboration and careful planning helped to ensure no negative effect on network assets or output during the upgrade.

Early challenges included the failure of legacy equipment originally earmarked for reuse, such as manganese blowers and seized valving arrangements. These issues were addressed through rapid redesign and procurement, ensuring the programme remained on track. Spatial constraints within the site presented further complexity, particularly during the construction of the new dosing chamber and associated pipework diversions. Temporary works and phased excavation strategies were implemented to maintain access and operational integrity.

Modifications to the clean water tanks (CWT1 and CWT2) were carried out under confined space protocols. The installation of actuated valves and bell mouth fittings required innovative approaches due to restricted access openings. Sequencing was critical, with CWT2 brought back into service prior to converting CWT1 into a dedicated un-chlorinated backwash tank.

All works were delivered on a live site, with embargo periods and planned maintenance activities carefully managed. Temporary dosing systems were installed to facilitate safe changeovers, and effective stakeholder engagement with NI Water operations teams ensured that risks were mitigated and service continuity maintained. The new soda ash plant was commissioned in April 2025 and has since been used as the pH controlling process, taking over from the old system.

The project also included the installation of a new potable water supply to the site, with future-proofing measures incorporated to support additional connections. Engagement with DfI Roads and NI Water Distribution Teams ensured compliance and coordination with wider infrastructure planning.

As part of the project, several process-driven improvements were implemented to enhance operational reliability, chemical dosing accuracy, and overall treatment efficiency.

Soda ash system upgrade: The existing soda ash silo was experiencing structural issues and material bridging, leading to inconsistent dosing. A new soda ash system was installed, comprising a silo with integrated shakers, blowers, and a batch tank. A third mixing/maturation tank was introduced to stabilise pH levels and eliminate dosing spikes. Strategically positioned at the opposite end of the building, it also shortens suction lines and improves soda ash solubility. This upgrade ensures consistent material flow and improved pH control, particularly important given the variable pH levels observed due to temperature fluctuations in Seagahan Reservoir.

Potable water protection measures: To prevent back siphonage and protect potable water quality, the supply to the backwash tank was removed following its conversion to an un-chlorinated backwash tank. A new supply line was established from the main distribution network, ensuring compliance with water safety standards.

Centralised control via MCC panels: Motor Control Centre (MCC) panels were installed to provide centralised control of all newly commissioned equipment. This integration enhances operational oversight and simplifies maintenance procedures.

Efficiency gains in backwashing: The transition to unchlorinated water for backwashing has led to reduced chemical wastage and improved backwash efficiency, especially during periods of poor water quality. This required careful reconfiguration of valving arrangements and blanking off interconnections between tanks to prevent contamination of clean water leaving the site.

Flow monitoring & chemical dosing control: A dedicated flow meter chamber was constructed to monitor flow rates of orthophosphate and chlorine dosing. The flowmeter also interfaces with an actuated valve to regulate the filling of CWT1, now designated as the backwash tank. This setup allows for precise control of chemical dosing and tank filling operations.

To protect operatives, the chlorine and orthophosphate are installed in separate chambers to reduce the risk during leaks. This item was identified during a hazard identification meeting.

Hydraulic improvements: The upstand level of CWT2 was increased to enhance hydraulic head, supporting improved flow dynamics across the system. An actuated valve was installed to prioritise flow between the backwash line and CWT2, ensuring that neither system is starved during simultaneous operations.

Water recovery gains: The backwash system was previously a bottleneck to reliable output, following review a hydraulic restriction in the lamellas was identified and addressed which allowed a greater flow to pass through them to reach their design capacity. This improved the overall efficiency and removed the bottleneck, providing headroom in the dirty wash water system and ultimately providing the works with more frequent backwashing facilities.

The Seagahan WTW Treatability Improvements Project incorporated a range of innovative and sustainable measures that enhanced delivery and long-term operational performance. By maximising existing assets and deploying efficient technologies, substantial carbon and financial savings were achieved, both in construction and ongoing operation.

A 3D scan of the GAC building was undertaken to address the absence of reliable as-built records. This enabled accurate coordination with the BIM model and informed the design of new equipment, including a bespoke mezzanine platform for the MCC panels, optimising use of available space.

Sustainability was embedded throughout the project. Excavated material was reused on-site for landscaping and reprofiling, eliminating disposal costs and reducing carbon emissions. Modular blocks were re-purposed for use on other sites, supporting circular economy principles.

The introduction of a third process tank and the use of un-chlorinated water for backwashing improved chemical efficiency and reduced waste, particularly during periods of algal blooms. Additional measures included the installation of a spill tank with integrated safety features and the design of dosing skids with enhanced access and flushing capabilities.

These innovations supported efficient delivery, reduced environmental impact, and aligned with NI Water’s long-term sustainability goals.

The project exemplifies sustainable infrastructure delivery, with substantial environmental and financial benefits realised through three key initiatives:

Overall, the combined impact of these measures in the first year is estimated to deliver a total carbon saving of 64 to 105 tonnes of Co2e and a cost saving of between £351,216 to £502,432.

The Seagahan WTW Treatability Improvements Project was successfully delivered on time and within budget driven by early contractor involvement, innovative design solutions, and a shared commitment to operational excellence and sustainability. With this project NI Water has been able to enhance operational efficiency, enable real-time monitoring via advanced SCADA telemetry, and has future-proofed the system for further instrumentation upgrades. Collaboration between the client, project manager, contractor and other key stakeholders was central to the execution of the project and its overall success.

The primary challenge driving this project was the inadequate storm volume capacity at Ramsey WRC. The existing storm tank could only hold 260m³, far below the required capacity set by the Environment Agency (EA).

Failure to increase the on-site stormwater storage capacity would result in a consent failure leading to the risk of environmental harm and regulatory penalties for Anglian Water.

Additionally, the site’s existing flow to full treatment infrastructure was outdated and in need of major repair and upgrade. The current system could not handle the additional flows required to meet future population growth and environmental obligations. Without intervention, Ramsey WRC faced operational inefficiencies and potential breaches of discharge permits.

To overcome these issues, Anglian Water tasked the @one Alliance to design a dual-scheme solution to address the stormwater storage and FtFT issues.

The new storm tank designed to significantly increase storage capacity and reduce overflow risk during heavy rainfall events. The new tank is 11.1m in diameter and 8.47m high. This provides an additional 693m3 of storage capacity bringing the total volume of stormwater storage to 953m3. This upgrade ensures compliance with Environment Agency requirements and future-proofs the site against climate change impacts and population growth.

To improve operational efficiency and safety, the design incorporates external dry well submersible pumps for automated cleaning. This innovation eliminates the need for manual cleaning and access platforms, reducing health and safety risks for maintenance teams.

Furthermore, the stormwater storage tank has been carefully integrated into the existing infrastructure, optimising the limited site footprint and minimising disruption during construction. This approach allowed the project team to deliver a high-capacity solution without extensive civil works or compromising ongoing operations.

The second element of the project focused on increasing the site’s ability to treat incoming flows during peak conditions.

Modular side-stream: Anglian Water implemented a modular side-stream solution supplied by Siltbuster Group, which offers flexibility and scalability within the constrained site layout. This system includes:

These technologies work in harmony to deliver robust treatment performance even under challenging conditions.

Supporting this advanced treatment process are associated pumps, flow splitters, and access platforms, ensuring smooth operation and ease of maintenance.

Tertiary solids removal: To further enhance effluent quality, the project has incorporated tertiary solids removal (TSR) through twin-stream pile cloth filters and disc filters from FLI Water Ltd, which provide an additional layer of protection for local watercourses.

Power supply: Recognising the increased power demands of these systems, the upgrade also includes a 315kVA electrical power enhancement, installation of a new LV switchboard kiosk, and integration of telemetry systems for real-time monitoring and control.

Collectively, these improvements enable Ramsey WRC to handle an additional 20 litres per second (l/s), bringing the total FFT capacity to 89.4 l/s, while ensuring compliance with stringent environmental standards.

Delivering this complex project posed several significant challenges that required innovative solutions and careful planning.

Coordinating these systems demanded robust design and commissioning strategies. The team mitigated risks by collaborating closely with specialist suppliers, ensuring seamless integration and reliable performance across all components.

The successful delivery of the Ramsey WRC upgrade was underpinned by a highly coordinated and collaborative supply chain strategy. Given the complexity of the dual-scheme approach, combining storm tank capacity upgrades with advanced flow to full treatment (FFT) enhancements, the project required contributions from multiple Tier 2 contractors and specialist suppliers, each playing a critical role in achieving the technical and regulatory objectives.

Work commenced in August 2024 and at the time of writing (January 2026) is scheduled for completion in the upcoming months; ensuring that all regulatory deadlines are met without delays.

The Ramsey Water Recycling Centre upgrade stands as a clear demonstration of Anglian Water’s commitment to resilience, regulatory compliance and environmental stewardship. By investing £10m into advanced treatment technologies and storm capacity improvements, the project not only addresses immediate operational and regulatory challenges but also future-proofs the site for AMP8 and beyond.

This strategic investment ensures that Ramsey WRC can continue to meet the growing demands of population increase and the tightening environmental standards that govern water recycling operations.

The flow to full treatment element of the investment is on track to achieve an 77% reduction against Anglian Water’s capital carbon baseline, which is key to supporting Anglian Water’s commitment to reaching a net zero organisation by 2030.

In 2022, Glanua Group was awarded a contract under the AMP7 WINEP Programme to design and construct a tertiary solids removal (TSR) plant incorporating Evoqua’s CoMag® technology from Xylem Water Solutions.

At £36.5m, the project represents a significant CAPEX investment and a key advancement in wastewater treatment performance, delivering enhanced solids and phosphorus removal efficiency.

By integrating innovative and sustainable treatment processes, the scheme will comply with stringent environmental standards and contribute to improved effluent quality and environmental protection.

The construction and MEICA installation of the TSR plant have been completed, and the project commissioning team is now operating the system in preparation for reliability testing and handover. The CoMag® TSR process is consistently achieving phosphorus concentrations well below the consent limit of 0.3 mg/l, demonstrating robust process performance and operational reliability.

The upgrade works includes five Flygt channel impeller pumps from Xylem Water Solutions to lift current final effluent to the TSR plant, via a distribution chamber, where flow from five inlets splits evenly into two streams.

Ferric sulphate is dosed upstream of the CoMag® reactor and continuously mixed to encourage the formation of flocs. A magnetite slurry and a poly-acrylamide solution are also dosed and mixed to add weight to the flocs, enhancing their settlement in the two 23m diameter clarifiers.

The scheme also includes the provision of an upstream ‘primary’ ferric sulphate dosing system, which is integrated into the existing treatment process. This adjusts the pH and phosphorous levels upstream of the TSR plant, allowing optimisation of the CoMag® system.

Blackburn Meadows TSR Plant - Courtesy of Glanua

The CoMag® system is a ballasted separation and recovery process. It utilises magnetite alongside coagulants to create a ballasted flocculation system, thus enhancing settling rates and increasing the performance of the wastewater treatment plant. The high-density, magnetite ballasted floc flows into a compact high-rate clarifier. The clarifier includes baffle plates to dissipate the velocity of the inflow, encouraging optimal settling, and a rotating rake directs sludge into the hopper.

The remaining 30% of the sludge is processed through magnetite recovery system, which includes an inline, high-speed shear mixer where the magnetite is separated from the floc. The resulting two-part slurry is then passed through a magnetite recovery drum.

The permanent and stationary magnets inside the drum help to capture and reuse more than 99% of the magnetite, meaning that once primed, the CoMag® operates with very low magnetite consumption and low OPEX.

The sheared sludge, minus the magnetite, flows into the wastewater pumping station, where it is returned to the main WwTW via a new rising main, discharging immediately upstream of the primary settlement tanks.

Originally, the WwTW’s final effluent discharged to the River Don via twin 1400mm brick-built culverts, buried at 6m cover to crown, which are believed to have been constructed in the Victorian era. A crucial and complex part of the scope was to excavate around and break into the culverts to enable flow diversion to the TSR. This required significant temporary works in the form of over pumping the final effluent and allow the culverts to be drained and isolated.

The number of shutdowns and over-pumping operations were minimised due to refinement of the construction sequencing and programme, reducing environmental risk exposure associated with temporary over-pumping installations. This accomplishment followed a huge effort by Glanua Group, Selwood and Yorkshire Water, and was completed under the guidance of, and in liaison with, the Environment Agency.

The condition of the culverts was largely unknown prior to excavation, with limited information available from trial holes. There were concerns about how the vibration from the sheet piling works would affect the culverts, during the installation of the cofferdam. As such, the temporary works design specified the use of silent piling technology with pre-augering to loosen the dense granular strata identified in the ground investigation.

Once excavated and broken out, temporary steel supports were affixed to the structural blinding, and mild steel pipework was installed to reintroduce flows, and decommission the over-pumping.

The TSR feed pumping station, utilising a cast in situ design, was constructed by Hernon ME around the temporary pipework, reducing the reliance on over-pumping from approximately six months to six weeks.

The Blackburn Meadows project was delivered through BIM 360, was Glanua Group’s Common Data Environment (CDE) and Information Delivery platform. This ensured that all project information was structured, reviewed, and approved within a controlled digital environment aligned with Glanua’s ISO 9001 Quality Management System and industry best practice for Digital Project Delivery.

Effective digital processes were central to how the project was delivered. By using the CDE, the flow of information was structured, auditable, and transparent across all design and delivery teams. This enabled consistent adherence to Glanua’s BIM and information management principles, ensuring the right information reached the right people at the right time.

Autodesk Revit was used for 3D modelling and drawing production across all disciplines (civil, structural, mechanical and electrical), which enabled integrated and coordinated design deliverables. The built-in review and approval workflows within Autodesk BIM 360 supported rigorous checking, digital mark-ups, and traceable approvals throughout design and construction.

The model coordination module was used by the entire project team and central at key design and construction milestones. Digital coordination reviews, HAZOPs, and ALM reviews were all conducted within the model environment to provide clear visual context. This approach improved decision-making, enhanced safety in design, and identified construction efficiencies, directly supporting programme delivery and quality outcomes.

Through the asset module in BIM 360, critical asset information was digitally captured and managed to support data-driven decision-making throughout the project. Each asset’s installation, commissioning and testing status was tracked and updated with specific information required to meet the client’s asset data handover.

By analysing this data, the project team was able to identify the most efficient point in the delivery process to input the information required on the client’s platform, ensuring accuracy and consistency were married with efficiency.

By beginning with the end in mind, operation, maintenance, and handover information was accurately collated throughout delivery.

Relevant commissioning checklists were also linked to these assets, allowing the commissioning team to directly access and complete commissioning data within Glanua Group’s Common Data Environment.

A total of 187 precast panels were manufactured, shipped and placed during construction of four of the five main structures which has shown a significant carbon saving, compared to the use of an in situ concrete solution.

A calculation from FLI Precast Solutions demonstrated that the cement content, reduced by 50% and replaced with ground granulated blast furnace slag (GGBS) in the design mix for the precast panels, would provide a total CO2e saving of 137.2 tonnes. By comparison, this saving is shown as the equivalent of not driving for over 1.1 million kilometres, or the carbon absorbed by 3430 trees growing for 10 years.

For the remaining in situ slabs and structures, the concrete volumes have been reviewed and rationalised where possible. For example, the proposed perimeter wall was changed from a design containing 0.80m3 of concrete per linear metre to an equally effective design containing just 0.16m3 per linear metre, an 80% saving of concrete on this item of scope, demonstrating that a critical review in a small area can yield a significant impact.

The five TSR feed pumps are controlled from large variable speed drives (VSDs), which are housed in individual sections of the main site MCC. Whenever a pump is running, an extractor fan pulls 3,760m3/hr of air though each VSD section, expelling it directly to the atmosphere external to the kiosk.

Replacement air is drawn into the kiosk through 30 vents in the kiosk wall. Whilst this is fine in summer, during winter months, the kiosk would require significant heating to avoid condensation forming inside the panels. It was calculated that 90kW of electric heaters were required in the kiosk to maintain an internal temperature of 10°C, when the ambient external temperature was -5°C.

It was considered too wasteful to provide so much heat, just for it to be exhausted to the atmosphere, in addition to the OPEX associated with this level of heating. In conjunction with supply chain partner, Air Technology Systems (ATS Climate), the VSD exhaust system was redesigned to include an air diversion and recirculation option, which automatically changes over based on temperature set points within the kiosk.

During a recirculation scenario, air is not extracted from the kiosk, meaning there is no low pressure causing cold air to be drawn in to the kiosk, eliminating the requirement for specialist heating of the kiosk beyond standard building services.

The introduction of the TSR plant at Blackburn Meadows is a significant investment by Yorkshire Water in the environmental protection of the River Don and the surrounding area. By embracing the new CoMag® technology, Yorkshire Water have signalled their intent to support innovative solutions when complying with tighter water quality consents to protect the environment.

Glanua Group would like to thank Yorkshire Water and all delivery partners involved who have collaborated to bring project together through proactive and solution-orientated design and build engineering.

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.

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 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.

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.

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.

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.

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.

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.

During the optioneering stage, a range of interventions were assessed to address the storm overflow impact, including catchment‑scale rainfall disconnection, increased pass‑forward flow, nature‑based treatment and conventional storage. Catchment disconnection was discounted due to the high levels of customer disruption required, while increasing pass‑forward flow was not feasible due to downstream hydraulic constraints. Given the overflow’s location adjacent to open land by the river, a nature‑based solution was identified as the most effective and deliverable option.

A two-stage approach was chosen to maximise success, with an aerated reed bed providing initial intensive solids capture followed by two Integrated Constructed Wetland (ICWs) in series, providing effluent polishing and an opportunity for the industry to research wetland treatment in this application.

The favourable topography enabled a gravity system, eliminating the need for lifting flows and in turn, reducing operational energy demands. The field’s proximity to New Inn’s residents also allowed for place-making features for the local community, such as footpaths, an outdoor classroom and natural play areas, enhancing community engagement and educational opportunities.

The indirect monetary value of these wider benefits was captured in the decision-making stage via the use of CIRIA’s B£ST estimation tool, which estimated £12m in realised benefits over the next 40 years across social, natural and other capitals; something none of the grey solutions offered.

The existing storm overflow (SO) was located amongst trees on the edge of the field. The incoming pipe laid in the eastern corner of the field meant the SO could be relocated into a new compound, which will contain the following chambers and plant:

Design for Manufacture and Assembly principles were adopted to several elements of the compound. The screening and bypass chamber were fabricated off site by FP McCann Ltd, reducing the need to cast these chambers in situ.

Both the kiosks were prefabricated off-site by Morgan Marine Ltd to save time and reduce on-site activities in the construction phase.

The design team carried out a catchment Flow & Load Survey to ensure a better understanding of the design parameters required to achieve the ‘No Impact’ outcome. The survey gave insight into the challenges around pollutant loads in intermittent discharges, with varying concentrations of biochemical oxygen demand (BOD) and ammonia found in the excess diluted sewage; especially the difference between accommodating the ‘first flush concentration’ and weaker dilutions as a storm event continued.

Working collaboratively with the reed bed and ICW suppliers early in this stage, increased confidence in achieving the necessary pollutant removal in the final effluent.

A Flood Consequence Assessment (FCA) was completed as part of the planning application and the findings required the reed bed and wetlands to be moved further away from the river, reducing the size of the originally allocated footprint. The revised layout however, still provided sufficient treatment area (3,000m2 for the reed bed and a combined ICW treatment area of 2,400m2) and created additional space for the public to enjoy.

The planning application was critical to the success of this project, which was well received by local councillors and relevant bodies, in part, due to the extensive up-front work done by Arup’s planning team. Arup specialist teams carried out predictive odour and noise modelling of the solution to address concerns raised by the planning authority. The project team also engaged extensively with the local community through both in-person and online events, ensuring the design met local needs and preferences.

To align with the Sustainable Approval Body (SAB) requirements as part of planning approval, the design team implemented sustainable drainage features across the site. The maintenance track and vehicle areas in the compound were constructed from permeable TruckCell™ paving, made from recycled plastic, whilst vegetated swales and depressions were incorporated alongside the impermeable access track and footpaths. This reinforced the project’s low‑carbon and sustainable design ethos.

Construction started in January 2024, with Morgan Sindall Infrastructure mobilising to bring the nature-based solution system online before the regulatory deadline of 31 March 2025. The team navigated challenges including invasive species within the compound area and persistent groundwater during the large excavations, requiring an extensive dewatering activity (under approved Abstraction Licences).

Working with the sub-contractors, Natural Wastewater Solutions (NWS) for the reed bed, and Salix River and Wetland Services and Vesi Environmental Ltd for the integrated constructed wetland, 33,904 tonnes of soil were removed and the ground re-profiled. 30,000 tonnes was re-used off site, whilst 3,000 tonnes was recycled and re-used on site, with the final 904 tonnes taken to landfill, due to the presence of Japanese knotweed.

Due to the impermeable nature of the soil, the reed bed and constructed wetland both required under-draining to minimise the impact on the groundwater table. Once the under-drains were installed, the basins were constructed, which included the following:

The site team pushed to see the first flows through the system just 12-months later, ahead of the 31 March deadline and handled the heavy rainfall from Storm Eowyn on 24 January without any issue.

A robust sampling regime is currently underway to understand the performance of the individual stages and final effluent from the nature-based solution. This will inform future permitting of these types of solutions in cooperation with the environmental regulator, Natural Resources Wales (NRW).

The initial sampling results are promising, with significant reductions in BOD, ammonia, total suspended solids (TSS) and phosphorus in the final effluent. River water quality sampling upstream and downstream of the outfall is also being carried out to understand the impact of the scheme on the Afon Lwyd.

Welsh Water is participating in the Chemical Investigation Programme (2025–2030) with UKWIR, where samples from the wetlands are currently being used to help understand bio-accumulation of emerging substances such as pharmaceuticals in intermittent discharges.

With the site due to open to the public soon, Pont-y-felin Lane exemplifies a paradigm shift in storm overflow management, demonstrating how nature-based solutions can deliver technical excellence, environmental restoration, and community enrichment, all while setting a precedent for low-carbon infrastructure in the water sector. The forward‑thinking optioneering, combined with the client’s commitment to selecting a nature-based solution, over traditional ‘grey’ options, has resulted in a scheme that proves natural solutions can deliver more sustainable outcomes, for less.

Anglian Water tasked its @one Alliance with identifying an effective and innovative solution to this issue. The conventional approach, iron dosing, would have needed major civil works, a new concrete base, modifications to the existing process, and an ongoing supply of iron chemicals. This would create ongoing costs, increased carbon emissions from deliveries, and higher operational complexity.

Instead, the team chose to challenge convention by developing Anglian Water’s first Integrated Constructed Treatment Wetland (ICTW) as a nature-based alternative. The final design created a three‑cell wetland covering 18,320m² (around 2.5 football pitches).

To build a wetland of this size, Anglian Water purchased the required land from a local farmer who owned the field downstream of the existing works. The existing outfall pipeline ran parallel to the farmer’s field and Tempsford Road, carrying the treated wastewater out towards the River Ivel. To feed the wetland, the team bypassed the start of that pipeline, diverting the water through the gravity-fed wetland before cutting back into the existing pipeline at the new wetland outfall location.

Over a six-month construction and planting period, the team excavated the three wetland cells and planted more than 110,000 native plants, including:

Emergent wetland plant species

Marginal wetland plant species

Like many capital projects, the Everton Integrated Constructed Treatment Wetland faced several challenges, including:

As the UK’s first ICTW, the project has drawn international attention. In November 2025, Anglian Water hosted officials from the Mexican Embassy and Government during a UK trade mission exploring innovative water management approaches. Grant Tuffs, Regional Engagement Manager, noted that the visit strengthened international collaboration and highlighted the value of nature‑based solutions in modern water infrastructure.

The wetland has also been visited throughout the earlier stages of the project by Richard Fuller, local Bedfordshire Conservative MP, showcasing the positive and widespread attention this project has received throughout its lifecycle.

Because no new dosing plant was needed, the existing site infrastructure and power usage remained unchanged. The planning and land acquisition process took three years, reflecting the complexity of delivering a first‑of‑its‑kind solution. This allowed the team to develop a robust, repeatable design for future wetlands planned across AMP8.

The Everton Integrated Constructed Treatment Wetland Project eliminated the need for chemical dosing, reducing lorry movements, operational carbon, and long‑term chemical costs. A deeper pond area was also created to encourage biodiversity and support local wildlife.

The Everton Wetland was completed in October 2025. With planting now established, full growth and system maturity are expected by Spring 2027. The plants have an indefinite lifespan but is likely to be between 30 and 50 years or more.

Overall, the project achieved an 84% reduction in carbon emissions, cutting the carbon footprint from 654 tCo2e to 104 tCo2e, largely due to balanced cut‑and‑fill earthworks that avoided imports and exports and the removal of 99% of anticipated concrete use.

The Everton Wetland Project demonstrates how nature-based design can deliver regulatory compliance while providing long-term environmental, operational, and carbon benefits. By replacing chemical dosing with an ICTW, Anglian Water has reduced costs, cut emissions, increased biodiversity, and created a blueprint for future schemes.

As part of the £37m wetland programme, the lessons from the Everton Integrated Constructed Treatment Wetland Project will shape the next generation of wetlands to be delivered across AMP8. This project represents a significant milestone in the UK water industry’s shift toward sustainable, resilient infrastructure.

Weather has a major impact on raw water quality. Typically, rainfall increases flow in the river and, with it, turbidity. Colour, an indicator of natural organic matter, reduces in wet weather and increases in drier spells. Climate change has increased the intensity of rainfall, and this reduces the pH of the river water, making control of coagulation, which depends on colour, turbidity and pH, more difficult.

Higher turbidity during storm conditions requires a higher coagulant dose, and this further depresses the pH. This issue has, on several occasions, resulted in a shut-down of the works which struggled to meet treated water quality goals. Southern Water notified the DWI of this process issue and were issued with an improvement notice which required a long-term solution to be implemented by 28 February 2025.

Southern Water engaged Trant Engineering to develop and implement a solution. Trant had a dedicated team at Sandown working on other schemes and had good working relationships with the Southern Water Project Team and Operations. This meant that they already had a good understanding of the problem and were able quickly to propose a solution consisting of chemical storage, pH control and a caustic soda dosing system together with all the associated piling, reinforced concrete plinths, paths, slabs and buried service ducts.

The proposed process solution treated chlorinated process water through dosing with sodium hydroxide within carrier water immediately prior to entering the contact tank. A measured dose is applied to the process, calculated by measuring pH and flow. The dose is then adjusted as required through a process feedback loop to maintain a required target pH set point.

Because of space constraints, the incoming raw water mains had to be diverted. The dosing system required a pH analyser/controller mounted on a backboard with process instrumentation, pressure sensors, level controllers and automatic valves. Carrier water pumps and a water softener completed the dosing package with an adjacent dosing control panel with PLC and HMI.

There were several key challenges. Highly limited space available for the equipment required, extensive buried services, and challenging project delivery timescales to meet the regulatory outputs. Working closely with Southern Water and the established delivery partners Atkins Realis, Chemidose and F W Marsh, Trant’s team was able to complete the necessary Design, HAZOP and ALM process early in 2024.

The design was prepared with programme constraints heavily in focus and incorporated an off-site ready built kiosk with integral floor. This enabled the full kiosk fitout to be undertaken in parallel with the civils work on site and resulted in significant programme improvement. The dosing system was fully FAT tested offsite at Chemidose’s premises.

Space was tight to fit the kiosk on site, and tight within the kiosk to fit the process equipment needed whilst maintaining good access. A collaborative design process and a great team enabled this to be achieved within the constraints. Challenges were encountered on the civils design including unmapped significant pipework and unfavourable geotechnical conditions in the only viable location for the kiosk. The team moved quickly to resolve solutions which required a piled foundation to address the ground conditions and avoid loading the unmapped pipework whilst diversion was resolved.

The civil works and on-site preparatory M&E works were completed in parallel with the dosing kiosk fitout. This combined with the level of offsite fitout and testing substantially minimised the on-site installation period. The dosing kiosk was delivered to site as the civil works were completed, and a limited period of M&E works were required to connect into the existing site process.

Within four weeks of the kiosk delivery, commissioning was able to commence. A successful commissioning period allowed project works to enter active service several weeks ahead of the DWI regulatory date for installation. The project achieved full formal handover well ahead of the DWI regulatory date for commissioning.

By close cooperation throughout the supply chain, commissioning was able to commence within four weeks of the kiosk delivery. Being familiar with the site, Trant’s Instrumentation, Control & Automation (ICA) team was able quickly to integrate the new controls, and the new works was in service and formally handed over several weeks ahead of the DWI regulatory date for installation.

The solution deployment has been successful in addressing the problem of low pH causing a need to shut down the works during periods of heavy rainfall and this success has been welcomed by all parties.