Supply Chain - Wastewater Treatment

Dereham Water Recycling Centre is one of over 1,100 Anglian Water WRCs and is located in North Norfolk, approximately 20 miles from Norwich within the Wensum Nutrient Neutrality catchment, serving an estimated population in excess of 25,000. The existing works was built in the 1980s and consists of two main treatment streams made up of traditional process blocks namely, primary settlement tanks, biofilters and humus tanks. Previous work undertaken on the site by Anglian Water included six new tertiary sand filters, which were installed in 2003. The challenge

The key driver for this project was Anglian Water’s obligation to meet new Compliance Flow to Full Treatment (cFFT) standards introduced under the Water Industry National Environment Programme (WINEP). Without intervention, Dereham WRC did not have sufficient hydraulic capacity to meet the new legal FFT requirement of 130.8 litres per second (up from 114 l/s) by 31 March 2025, which could have led to breaching permit conditions and facing significant penalties.

[caption id="attachment_24600" align="alignnone" width="1200"] BIM model of works - Courtesy of @one Alliance[/caption] Design

Anglian Water tasked the @one Alliance and its supply chain partners to fullfil the scope, and to undertake a complex engineering challenge. Initially, the design centred around a traditional sidestream solution including primary settlement tanks (PSTs), submerged aerated filters (SAFs), and high-rate sedimentation tanks (HSTs). However, it quickly became clear that this approach would not work due to the limited site space, the need for extensive enabling works, and potential delays from planning approvals and environmental assessments; all of which presented major hurdles.

In light of these issues, the project team undertook a high-level review  and chose a smarter, modular route forward.

The solution

To manage the increased flow to full treatment and achieve compliance with tighter water quality standards, the @one Alliance team installed a state-of-the-art modular sidestream treatment system designed for performance, resilience, and minimal environmental impact.

Central to this system was the introduction of a new above-ground pumping station, purpose-built to efficiently transfer increased flows through the new treatment process. This strategic addition allowed for greater operational flexibility while helping to future-proof the site for further expansion should it be needed.

[caption id="attachment_24604" align="alignnone" width="1200"] Installed lamella clarifiers - Courtesy of @one Alliance[/caption]

The sidestream process featured three modular technologies which provided a robust, scalable, and energy-efficient treatment solution:

Lamella clarifiers

Selected for their ability to deliver high-performance settlement within a compact footprint, the lamella clarifiers efficient solid-liquid separation capabilities significantly enhances treatment capacity without requiring major alterations to the existing site layout.

Moving bed biofilm reactors (MBBR)

In addition to the lamella clarifiers, MBBRs were installed, which use specialist biofilm media to support biological treatment under increased loading. These reactors not only improve the quality of the final effluent but also offer improved reliability and easier operation compared to traditional systems.

Dissolved air flotation (DAF) units

Completing the system were DAF units which are key to optimising solids removal and enhancing overall process performance.

Off-site fabrication

By prefabricating key system components off-site, the @one Alliance was able to significantly reduce on-site construction time, lower embodied carbon, and minimise disruption to the surrounding environment and community. This approach also reduced the need for complex groundworks, helping the team to stay on programme and adapt quickly to changing site conditions.

[caption id="attachment_24603" align="alignnone" width="1200"] MBBR tanks & walkway - Courtesy of @one Alliance[/caption] Infrastructure upgrades

Delivering this advanced solution also required major upgrades to both the electrical and civil infrastructure on site. A ground-mounted kiosk was installed to replace the old pole-mounted substation, improving power resilience and safety.

The Press House building on site had previously been condemned due to safety concern but following an extensive refurbishment it was brought back into operational use to house a new, modern low voltage switchboard.

This upgrade has not only made the site safer but has also provided a more efficient and accessible control centre for Anglian Water’s operational teams, improving both maintainability and monitoring.

To support the new assets, an extensive network of underground ducting and cable management systems were installed ensuring seamless connectivity between each element of the treatment process. A robust concrete base slab was constructed to support the weight and vibration of the Siltbuster Ltd sidestream units, as well as associated blowers from AERZEN Machines and de-sludge pumps from NOV.

To ensure long-term structural integrity, piling operations were carried out to reinforce the site’s foundations. In addition, new underground pipework and flow distribution chambers were installed, enabling smooth and efficient transfer across the various treatment stages.

[caption id="attachment_24598" align="alignnone" width="1367"] Delta blowers from Aerzen Machines - Courtesy of @one Alliance[/caption] Dereham WRC: Supply chain - key participants Project delivery: @one Alliance Principal contractor: Skanska Base slab & civil works: Bell Formwork & Civil Engineering Services Ltd Overpumping: Selwood Mechanical & electrical installation: Glasswell & Last Ltd MCC supply & integration: TES Group Modular treatment units: Siltbuster Ltd Ferric sulphate dosing system: EPS Water Access metalwork: Steelway Building refurbishment: Claret Civil EngineeringLtd Piling works: Roger Bullivant Ltd Valves: AVK UK Ltd Blowers: AERZEN Machines De-sludge pumps: NOV Pipework: Saint Gobain PAM UK Pipework: Wolseley Pipework: SC Pipelines Ltd Safe asbestos removal: Oracle Solutions Asbestos Ltd Impacts & benefits

With the upgraded FFT capacity of 130.8 l/s, Dereham WRC now fully meets regulatory requirements, helping protect local rivers and wildlife from untreated discharges.

The modular design provides flexibility for future growth, enabling additional units to be added quickly and cost-effectively as needed.

The operational benefits are clear. The modular treatment system is easier to access and maintain, streamlining ongoing operations. The MBBRs and DAF units provide high performance while consuming less energy, ensuring long-term efficiency.

[caption id="attachment_24605" align="alignnone" width="1200"] MBBR biofilm media: (top left) media ready for loading, (bottom left) crane lift, and (right) media installation - Courtesy of @one Alliance[/caption]

Significant strides were made to reduce the environmental impact. By reusing the existing Press House, the carbon costs associated with new construction were avoided and off-site prefabrication played a key role in reducing on-site emissions and vehicle movements, contributing to a lower overall environmental footprint. Additionally, refurbishing the Press House eliminated legacy health and safety risks; creating a safer working environment for on-site personnel.

As Dereham continues to grow, the upgraded WRC now provides the necessary capacity for new homes and businesses, all while ensuring water quality remains protected.

Conclusion

Despite the complexity and scale of the works, the project team worked diligently to keep the water recycling centre fully operational throughout construction, and overcame tight lead times and site constraints to deliver a high-performing, future-ready solution.

Through meticulous planning and phased delivery, we successfully integrated the new sidestream system into day-to-day operations, delivering critical upgrades with zero unplanned disruption to service. This seamless transition showcases what’s possible when innovation, collaboration, and smart engineering come together with a clear purpose: to protect the environment and support our growing communities.

[caption id="attachment_24602" align="alignnone" width="1200"] Overground pipework - Courtesy of @one Alliance[/caption]

The Dereham WRC upgrade is a good example of how innovation, sustainability and collaboration can come together to solve complex challenges. By choosing a modular, low-impact solution, a compliant, efficient, and resilient water recycling centre was delivered.

Working together to protect the environment, support local growth, and deliver long-term value for customers, it stands as a blueprint for how Anglian Water and the @one Alliance will tackle similar challenges across the region throughout AMP8.

Broadholme Water Recycling Centre (WRC) is located off the A45 near the Rushden Lakes Shopping Centre in north Northamptonshire and provides water recycling capability across the Rushden, Wellingborough and Irthlingborough areas. There are multiple large lakes in the area, all fed by the River Nene including the Nene Wetlands Nature Reserve and a Site of Special Scientific Interest (SSSI) Water Reserve in close proximity to the recycling centre. The works was showing signs of beginning to struggle with the increased demand and this was cemented by a change in the Environment Agency (EA) requirements for the site when it came to its full flow to treatment (FFT) and phosphorus removal capacity. Background

Broadholme WRC is a well-established operational site which treats wastewater from Wellingborough and surrounding catchment areas before returning it safely to the environment. Prior to the project starting, it had a treatment capacity of 233,533  population equivalent (PE). As with all water companies, Anglian Water carries out a range of works across its sites to ensure that it can continue to meet the needs of the local area as it continues to expand and to both improve and protect water quality in line with regulatory requirements as part of the Water Industry National Environment Programme (WINEP).

[caption id="attachment_16552" align="alignnone" width="1200"] Overview model - Courtesy of @one Alliance[/caption]

According to the 2021 census data the population the United Kingdom has increased by 6.3% since 2011, however the East of England has seen the highest levels of population growth per region at 8.3%. Both these figures are low in comparison to the level of growth in north Northamptonshire which has seen the population increase by 13.4% since 2011 to now over 400,000 residents.

To meet the new EA requirements in time for the site’s obligation date in March 2025, Anglian Water handed the design and construction of this scheme to its in-house capital delivery vehicle the Anglian Water @one Alliance as part of its AMP7 portfolio.

The Alliance is formed of eight partner organisations including Anglian Water, Balfour Beatty, Barhale, Binnies, Mott MacDonald Bentley, MWH Treatment, Skanska and Sweco. Each partner brings its own specialisation to the Alliance, which allows @one to efficiently deliver large capital delivery projects included in its £1.2bn AMP7 portfolio.

Project delivery

The site team, led by the principal contractor Mott MacDonald Bentley are delivering the Broadholme Water Recyling Centre project which is currently valued at £35m, making it the largest combined scheme that the Anglian Water @one Alliance has delivered in AMP7.

Broadholme WRC: Supply chain - key participants Principal contractor & designer: @one Alliance Mott MacDonald Bentley In situ soil stabilisation: SMR (UK) Ltd Sequential batch reactor: Xylem Water Solutions Pile cloth filter: FLI Water Ltd Power upgrade: Power Testing Limited Glass-coated steel tanks: Hayes GFS Ltd MEICA package: TES Group Ltd Chemical storage & dosing: Lintott Control Systems Ltd Access walkways: Steelway Lifting equipment: Cadman Cranes Ltd [caption id="attachment_16557" align="alignnone" width="1200"] Phosphorous removal scheme - Courtesy of @one Alliance[/caption] Solution

With the site facing new EA requirements for growth, full flow to treatment (FFT) and phosphorus removal, the @one design team was required to create a solution that would work together to achieve all of these obligations and come up with a cohesive solution that could increase the sites dry weather flow (DWF) by increasing the FFT capacity to a level that would ensure the WRC does not spill to storm in dry weather and that the contents of the storm tank are able to be returned for treatment as soon as is reasonably possible.

Failure to meet the new FFT and phosphorus consent could create a significant pollution risk for the scheme under significant inclement weather conditions.

Utilising modern design principles, the team made use of 3D modelling software to create a virtual 3D map of the site and the planned works which could be viewed in virtual reality (VR). This was to allow the designers and engineering teams to virtually view the scheme together, as it was being designed to ensure the required additions to the WRC could be transplanted in as easily as possible given the limited amount of space available on the existing site.

The final design for the scheme was to install four new sequential batch reactor (SBR) tanks from Xylem Water Solutions to allow for the increase in FFT capable of providing 413 l/s of additional capacity alongside a 60m3 ferrous dosing package to provide additional phosphorus removal.

[caption id="attachment_16559" align="alignnone" width="1200"] Phosphorous removal scheme - Courtesy of @one Alliance[/caption]

To accommodate the power needs of the new assets, the existing power supply was upgraded, and a new transformer was provided on-site. A standby generator and fuel tank has also been added to run critical plant in event of a power outage.

The team then began work on the concrete base for the SBR tanks creating a 75m x 75m base slab which included drainage channels, before laying another four raised 35m diameter concrete plinths for the tanks to sit on; based on the redundant space our team had dug up of the old beds. These concrete pours created a logistical challenge for the team as each of the four plinths needed over 570m3 of concrete which required over 75 mixers worth of concrete coming back and forward into the site per plinth along a narrow access road.

Alongside the SBR plinths, the team also built a new motor control center (MCC) plinth, blower plinth and ferrous dosing plinth, alongside steelwork for the new MCC, blower platform and pipework.

The tanks were each built by Hayes GFS Ltd from the top down by creating each ring at ground level before using hydraulic jacks to lift the ring into the air creating space underneath for the next ring to begin its installation.

This method created a safer working environment for the installation team by removing any requirement to work from height. Once constructed each SBR tank will be five rings high reaching 7m in height with a 35m diameter.

During the installation of the tanks the team also had supplier Steelway on site building walkways around the outlet side of the tanks to allow for site access.

In order to feed the new SBR tanks the team had to lay a new 310m, 710mm diameter high-density polyethylene (HDPE) crude sewage pipe which runs alongside an existing inclined access road frequently used by Anglian Water tankers. This new pipe, once fusion welded into place, connects the existing Inlet Works Number 2 to the new SBR tanks via the new common distribution chamber.

[caption id="attachment_16554" align="alignnone" width="1200"] One of the new SBR tanks - Courtesy of @one Alliance[/caption] Challenges

With the scheme being the largest scheme in terms of financial investment of Anglian Water’s AMP7 programme, it comes with its own challenges.

Broadholme WRC sits within/adjacent several designations (eg Ramsar, SPA) resulting in the need for screening opinion, and possibility of EIA, for the whole scheme. Extensive surveys and assessments were needed as part of the screening process taking over ten months. This in turn affected start on site reducing the construction window ahead of the obligation date.

During construction, we also encountered some challenges. With several components of the phosphorus cloth filter and SBR tanks coming from overseas, shipping coincided with the start of issues in the Red Sea, so re-routing of components added some delays to the expected programme of work.

Also, during the installation of this scheme, the project team have had to deal with extremely poor weather conditions due to extensive rainfall during the Winter of 2023 and much of 2024, which impacted the delivery of the civils works. Due to increased demand for resources across the country, lead times at pre-commencement have been increased which therefore hindered our programme dates; particularly affecting the MCCs and large diameter valves and pipes.

[caption id="attachment_16558" align="alignnone" width="1200"] (left) Preparing for concrete pours and (right) concrete pours - Courtesy of @one Alliance[/caption] As part of this scheme, the team is completing the renewal of the access road into Broadholme WRC, which includes over 1km, split into tarmac and concreting for Anglian Water personnel. These works are being completed overnight to maintain tanker access as the road does not have enough width to shut half the carriageway while leaving enough space for safe access. Progress

At the time of writing in September 2024, the four SBR tanks have been successfully installed and the team are working hard to complete the phosphorus and growth elements prior to the obligation date for the completion of the works.

Goddards Green Wastewater Treatment Works (WwTW) is a Sludge Treatment Centre (STC) located near Burgess Hill in West Sussex. The catchment serves the towns of Burgess Hill, Hassocks, Hurstpierpoint and surrounding villages, providing for 54,789 people. The project implements an innovative approach to mitigate the likely odour from the processes at the WwTW to prevent any potential impact on the planned Northern Arc development in the surrounding area.  To enable the new development to proceed in the surroundings of the WwTW, there was a planning requirement for the odour of the WwTW to be limited to 1.5 OUE/m3 odour contour. Existing works The main components of the WwTW consist of inlet works (screening and grit removal), storm tanks, a primary settlement tank, anoxic tanks, oxidation ditches, returned activated sludge pumping station, final settlement tanks and disc filters. Treated final effluent is discharged into the River Adur East. Besides indigenous sludge, the STC also processes imported sludge (liquid and cake). The main components of the STC consist of sludge reception and storage facilities, screening and screened sludge storage, drum thickening, anaerobic digestion, digested sludge storage tanks, centrifuge dewatering and cake storage bays. Liquors from the sludge treatment process are treated in a cyclic activated sludge system (CASS) plant before being returned to the WwTW. Hot water for digester heating is produced by burning biogas either in hot water boilers or in the 800 kW CHP (combined heat and power) engine. Northern Arc development The Burgess Hill Northern Arc is a development in the southern part of the parish between Ansty and Burgess Hill. The project spans a period of over 15 years. Once complete it will provide 3500 houses with 30% affordable housing, four hectares of employment land, a community centre, two primary schools and a secondary school. The project is being run by a government agency, Homes England, and is a strategic development which is part of the Mid-Sussex District Council Development Plan. Southern Water’s project at Goddards Green WwTW aims to deliver a range of odour mitigation improvement measures; removing barriers to the housing development at the Northern Arc. Southern Water have committed to delivering a scheme that achieves a 1.5 OUE/m3 limit for a boundary as defined by the odour contour image (see below). [caption id="" align="alignnone" width="1200"] Odour model emission contours for selected solution - Google Maps[/caption] Project synopsis This scheme is being delivered in two phases. Phase 1 was delivered in May 2020 with the installation of a new odour control unit and odour covers to reduce odour emissions at the site. Phase 2 comprises the installation of a thermal hydrolysis plant (THP) with associated equipment, provision of a cake reception building to control odour during deliveries and a cake barn to protect the product from the weather. The THP will reduce odour emissions from the sludge treatment process, improve sludge quality and enhance gas yields from the digesters. The outcome will mean that new housing developments in the area will be better protected from odour emissions. Output of the THP process will provide enhanced treated sludge for farmers to spread to land as well as greater green energy production from the existing CHP engine, reducing the site’s need to draw power from the National Grid. Funding Mid Sussex District Council, in collaboration with Southern Water and West Sussex County Council, successfully secured government funding of £10.54m under the Local Enterprise Partnership (LEP) Growth Deal (Programme) and the Homes England Housing Infrastructure Fund. Southern Water has invested an additional £17m to deliver the odour and sludge treatment upgrade project. Phase 1 scope Phase 1 was delivered in May 2020 and comprised the installation of a new odour control unit and odour covers to reduce odour emissions. High odour emitting existing asset sources as identified from the odour model were covered. These assets included the primary settlement tanks, liquid sludge reception tank and oxidation ditch distribution chamber. [caption id="" align="alignnone" width="1200"] Phase 1 odour control unit from ERG (Air Pollution Control) Ltd - Courtesy of Galliford Try[/caption] Phase 2 scope The current practice of blending imported cake with indigenous liquid sludge has been retained. The blended sludge is then screened using existing strain presses and thickened using existing drum thickeners. New centrifuge feed pumps have been installed to feed thickened sludge to the existing centrifuges - these were previously used for digested sludge dewatering but have been repurposed to produce raw cake for the new THP process. Conveyors transfer the dewatered sludge to duty/standby cake hopper pumps which deliver raw cake to a 130m3 cake storage silo. Cake from the silo is discharged to duty/standby hopper pumps where dilution water is added to achieve a target dry solids content of 16.5% DS in the THP feed sludge. A single Cambi B2-4 THP stream is provided, capable of processing up to 24 tDS/d. The first vessel in the THP is the pulper which homogenises and pre-heats the sludge. Pre-heated sludge from the pulper is fed to the reactors in a sequential process that ensures sealed batches of sludge in each reactor. Steam is injected to raise the temperature of the sludge in the reactor to 165°C at a pressure of about 6 bar. At the end of the hydrolysis period, hydrolysed sludge is discharged from the reactor to the flash tank, which operates at about 0.2 bar. The sudden drop in pressure ruptures any remaining biological cells in the sludge. Flash steam generated by the pressure drop is returned to the pulper to preheat the incoming sludge. Thermal hydrolysis of sludge generates a highly odorous off-gas (referred to as ‘process gas’) which is continuously extracted from the pulper and passed through a cooler, with condensate from the cooler gravitating back into the pulper. Non-condensable gases pass from the cooler to the process gas unit where they are pressurised and injected into the digester feed lines (downstream of the sludge coolers). [caption id="" align="alignnone" width="1200"] (top & bottom left) BIM models showing the THP plant area and (bottom right) Phase 2 THP area looking north-west - Courtesy of Galliford Try[/caption] Digester feed pumps are used to pump hydrolysed sludge from the flash tank to the digesters. Disinfected process water is added to the suction side of the digester feed pumps to dilute the hydrolysed sludge to achieve the target digester feed sludge dry solids content. Diluted hydrolysed sludge is combined with recirculated digested sludge before being cooled while passing to the two existing digesters. The new digested sludge dewatering stage comprises new duty/standby centrifuges and an associated polymer preparation/dosing system. Enhanced treated cake is conveyed to the new cake barn. There is an existing 800 kW CHP engine. High grade waste heat from the CHP engine exhaust gas is recovered in a new composite steam boiler. Low grade heat is also recovered from the CHP engine jacket cooling water and used to pre-heat the boiler feed water. These heat recovery systems help to minimise the consumption of supplementary fuel (biogas or diesel) required to meet the THP steam demand. A new final effluent (FE) pumping station supplies cooling water to the sludge coolers. All applications requiring dilution or carrier water are supplied with filtered FE that has been UV-disinfected, ensuring that an enhanced treated cake is produced. The schematic diagram below shows the process stages with the additional odour reduction measures undertaken in Phase 1 (in green) and the main changes to the sludge treatment process for Phase 2 (in orange). [caption id="" align="alignnone" width="1200"] Schematic showing the process stages - Phase 1: Additional odour reduction measures (green) and, Phase 2: The main changes to the sludge treatment process (orange)[/caption] Design Galliford Try’s (GT) inhouse engineering team based in Stafford, have undertaken and coordinated the detailed design process, supplemented by specialist suppliers. Atkins were also contracted to undertake the civil engineering design on behalf of Galliford Try. Southern Water carried out the process design. Regular design coordination meetings have been held between all parties to ensure a coordinated approach to the design. 3D and Building Information Modelling (BIM) modelling has been used throughout the scheme to coordinate and manage the design process. Viewpoint for Projects was used as the project’s cloud-based collaboration tool throughout. The use of 3D modelling was particularly useful in spotting clashes and to enable early process plant operator involvement and feedback. This has been beneficial in highlighting access and maintenance issues, prior to construction work beginning. [caption id="" align="alignnone" width="1200"] View looking at Serpecon conveyors and pre-THP silo feed pumps - Courtesy of Galliford Try[/caption] Goddards Green WwTW - Supply chain: key participants Client: Southern Water Main contractor: Galliford Try Outline design: Stantec UK Detailed design: Atkins THP plant: Cambi AS Cake reception building/cake barn: APT Engineering Ltd Imported cake reception silo: Saxlund International Ltd Steam boiler package: Dunphy Combustion Ltd Groundworks drainage: TC Jones Groundworks Concrete cutting/diamond drilling: Castle & Pryor Ltd Workforce supply: Hercules Site Services Workforce supply: Fortel Group Kiosks: Morgan Marine UV Treatment: Xylem Water Solutions - Wedeco FE booster set & portable water booster set: KGN Pillinger Pre-THP centrifuge screw conveyors: Serpecon Ltd Vehicle exhaust: Air Technology Systems CHP exhaust flue: Rung Heating CHP pipework modifications: Edina UK Ltd MCCs: Blackburn Starling Ltd LV Switchboard/MCC 10: MCS Control Systems Ltd Final dewatering units & access platform: Alfa Laval Biogas booster system: DSL Building Services Final dewatering polymer system (powder): Richard Alan Engineering Mechanical/electrical installation: Field Systems Design Ltd Submersible centrifugal pumps: Xylem Water Solutions - Flygt Pumps Concrete: Hanson Aggregates Muck-away: Hesus UK Ltd Sub-base materials: Day Group Ltd Drainage materials: Jewson Civils Frazer Heat exchangers: HRS Heat Exchangers Ltd Reinforcement: Hy-ten Ltd Pumps: P&M Pumps Ltd Draeger control units: Draeger Safety UK Ltd DS monitors: Flow Technology Services Ltd Valves & instruments: ABB Ltd Valves & instruments: Siemens Valves & instruments: Glenfield Invicta Ltd Valves & instruments: Xylem Water Solutions Instrumentation: IFM Electronic Ltd Performance monitoring & operational support: PBJ Engineering Services Ltd Supply of steam boiler water treatment chemicals: EB Critical Engineering Services Ltd Construction Construction of the Phase 2 works commenced in the spring of 2021 with the clearing of existing cake bays and the construction of new openings to the existing structure. Castle & Pryor Ltd undertook the work to create new openings, utilising track saws and robotic demolition techniques. The decision for this technique was taken to minimise the health and safety risks associated with more traditional demolition methods. Once the new openings were formed, Galliford Try went on to construct new foundations to accommodate the new process units. Hercules Site Services and Fortel Group were engaged to supply the necessary skilled workforce to work directly under Galliford Try’s own control. [caption id="" align="alignnone" width="1200"] THP area looking north east - Courtesy of Galliford Try[/caption] This approach has proved successful throughout the first three years of the current programming AMP7 period (2020-2025) as it affords greater flexibility and control. Wherever possible the existing structure was retained and re-purposed to speed up the construction, and to reduce overall costs and the carbon footprint of the scheme. Before reusing the foundations, detailed in situ and pull-out testing was undertaken. The Cambi B2 unit and associated ancillary equipment are all located within the original cake drying beds. In parallel to the cake bay works, construction was undertaken within the existing plant to facilitate the installation of the other process units. This required close collaborative working between the contractor and the onsite operations team, to minimise disruption to day-to-day activities and the running of the treatment plant. Throughout the scheme, this close cooperation has continued, ensuring all stakeholders are kept up to date with activities and progress. Field Systems Design Ltd was engaged by Galliford Try to undertake the detailed design and installation of the complex interconnecting cabling and mechanical piping systems throughout the scheme. This included high voltage cabling and transformer upgrade works, low voltage power cables, signal cables and fibre optic networks. The scope of the mechanical supply included all piping and access arrangements, steam lines and pressure networks. In total, 48 kilometres of cable, 2.5 kilometres of pipes and associated support systems have been installed. These systems are predominantly placed above ground for ease of future maintenance, and to mitigate the risks of burying equipment within an already congested plant. Collaborative planning and design management have been undertaken between the site team and Galliford Try, to ensure the smooth flow of the mechanical and electrical phase of the works. Overall, the scheme is now (June 2023) approaching 200,000 hours worked without any lost time or other significant incidents. [caption id="" align="alignnone" width="1200"] View looking north-east towards the Saxlund pre-THP cake silo - Courtesy of Galliford Try[/caption] Risk management De-risking of the construction phase was considered key to the delivery of project. To achieve this, regular risk reviews and workshops have been undertaken throughout with significant benefits being realised. For example, the project team identified early on that Southern Water were best placed to deliver the improvements to the existing on site gas storage facility and flaring arrangement in advance of the main Phase 2 works starting. It also identified the need to procure longer lead-in items in advance of the main contract award being in place. This meant that the Cambi B2 unit, Dunphy boiler building, and Saxlund pre-THP silo were all procured under an early works agreement. This joined up approach to risk management meant that the scheme was able to rapidly adapt to the challenges posed by the worldwide semi-conductor shortage. The shortage affected the project, due to the multiple control panels and complex equipment being procured. The team agreed to utilise refurbished parts within the panels to enable off-site fabrication and factory testing to take place. These refurbished parts will then be replaced on site once the delayed components become available, which has saved many weeks of further delay. Stakeholder management As Southern Water had obtained funding from Homes England to undertake the odour reduction scheme at Goddards Green, they were identified by the project team as key stakeholders. It was therefore essential that they were kept informed of progress throughout the delivery phase. To achieve this, the project team held regular site tours and liaison meetings with the representatives of Homes England and the local council members, fielding questions and explaining the process and progress on site. [caption id="" align="alignnone" width="1200"] (top left) BIM model showing the steam boiler system, (top right) the rear of the steam boiler building and emissions stack, (bottom left) the front of the steam boiler building and emissions stack, and (bottom right) the Dunpy boiler package - Courtesy of Galliford Try[/caption] DfMA - Design for Manufacture and Assembly Design collaboration from the earliest stages of the project has provided tangible benefits in terms of costs, speed, sustainability of the project, and health and safety benefits. These small but practical examples are a core part of Galliford Try’s sustainable growth strategy. Galliford Try’s installation of the steam boiler at Goddards Green WwTW using an off-site solution, has reduced construction time on site as well as bringing health, safety, carbon, and community benefits. Manufactured and installed by Dunphy, the modularised plant room was fully fired and tested off site before delivery in two days using DfMA to allow modular construction of the building and plant, reducing the amount of time spent on site during the installation. The reduction of time spent working on site also has health and safety benefits, as more work is completed in a safer factory setting, and many of the hazards of a live site can be reduced or avoided. Conclusion At the time of writing (June 2023) the Goddards Green WwTW project’s construction phase is nearing completion and commissioning works have commenced on ancillary equipment. Beneficial use is currently forecast for the end of 2023. The use of THP is the first of its kind within Southern Water. Therefore, despite being utilised to manage odour, it will also alter the way the sludge is managed on site, contributing to several economic and environmental benefits.

Built in the early 1960s, Bristol’s water recycling centre (WRC) at Avonmouth serves a catchment encompassing Bristol, South Gloucestershire Council, and parts of the Bath & North East Somerset (B&NES) and North Somerset Council areas. With the population of Bristol projected to increase significantly in the next 20 years, further treatment capacity is needed to meet these demands, ensuring a greater volume of sewage can continue to be treated to the highest standard, while also protecting the environment by improving the quality of treated wastewater released into the Severn Estuary. The expansion will ensure that the permitted flow to full treatment is increased and avoid spills to storm or to the environment on dry days. Existing works & project scope

The existing site currently treats up to 3,672 l/s. If this is exceeded due to high rainfall in the catchment area, the additional flow is diverted to the storm tanks. This new project will allow the additional treatment of flow up to 5,700 l/s, reducing spills to storm tanks, which will future-proof the site based on forecast population increases in Bristol and the surrounding area.

As the flow enters the site, it is screened and grit is removed. From here, the flow passes along the inlet channel and through to the primary settlement tanks (PST) where settlement occurs and the flow weirs over to the next stage of the process. There is then a split to either send the flow to the activated sludge process (ASP) lanes or into the sequencing batch reactor (SBR), where flow is aerated to allow bacteria to react with the flow. The final effluent then flows to the Severn Estuary via the culvert that runs through site.

The new project will increase the capacity of flow treated by approximately 60%. A key challenge of the expansion works is to ensure that the existing site can continually treat flows while construction takes place.

[caption id="attachment_25318" align="alignnone" width="1200"] 3D BIM model of existing and new works - Courtesy of YTL Construction UK[/caption] Design approach

The design process started in 2019 with the application for planning permission for the expansion submitted in the spring of 2023, following lengthy public and stakeholder consultation.

The design included a review of the existing process at the Optioneering Stage which identified the opportunity to optimise the existing SBR process, thus allowing the removal of old processes on site, freeing up space for future upgrades. The layout of the new works was developed to allow for future expansion as well as accommodating site constraints including maintenance access for wind turbines and ecological constraints.

The full design was modelled in REVIT and Civils 3D and this was useful in communicating the design with Wessex Water Operations at multiple stages throughout the design process.

Ground conditions

The ground conditions are poor and there is significant contamination present due to previous industrial processes in the Avonmouth area. Earthworks and landscaping was developed on the basis of minimising the amount of material that needs to be removed from site and recycled. This included building up ground levels around the PSTs, which also removed the need for extensive steelwork access platforms. This design approach saved significant vehicle movements and costs associated with contaminated material removal as well as the associated carbon savings for vehicle movements and steelwork. This piece of work has been nominated for the Best Sustainable Reuse of Materials Category at the Brownfield Briefing Awards.

[caption id="attachment_25319" align="alignnone" width="1200"] Commencement of the 90,000 tonne working platform - Courtesy of YTL Construction UK[/caption]

Additionally, there has been significant settlement modelling done at interfaces between structures and infrastructure. Nearly 4000 precast concrete piles of around 20m long have been used for the majority of the large structures.

Computational fluid dynamics (CFD) confirmed that the load split between the new and existing process streams matched the 60:40 flow split. This was done by adding solids to represent the incoming sewage and also return liquor flows as part of the CFD analysis and the results were then analysed in a mass balance approach to confirm the load split across the full range of flows to the WRC.

The new works

Inlet pumping station (screened sewage pumping station)

A new transfer pumping station of concrete construction, consisting of six submersible pumps which transfer 2,400 l/s from the existing works inlet to the new process stream on the new site. Connections and alterations to the existing assists have been a significant design and construction challenge for the project to overcome.

Primary settlement tanks

 The primary settlement tanks are 39m in diameter, with a working settlement volume of 3,917m3 each, with three-quarter bridge scrapers forming the first part of the treatment process once the incoming flow has been screened and pumped across to the new site.

[caption id="attachment_25322" align="alignnone" width="1200"] Construction progress of the PSTs - Courtesy of YTL Construction[/caption]

Settled sewage pumping station

A new settled sewage pumping station, comprising four submersible pumps is being construction, which will lift 2,400 l/s of sewage to the SBR distribution chamber and distribute the flows to the new sequencing batch reactors.

Sequencing Batch Reactors (SBR)

Eight new SBR basins are required, each 30m wide x 60m long 7m high, with a capacity of more than 12,500m3 each.

The existing works process uses a sequenced basin batched fill method, including aeration, settlement and decant. This technology uses aeration blowers with jet air introduction into the basins.

The technology selected for the new site works follows the process principles of aeration and settlement, with the Sanitaire ICEAS Advanced SBR system from Xylem Water Solutions selected for the project. This process differs from the existing process, with a continuous fill of all basins, including aeration, settlement and decant.

Xylem’s ICEAS Advanced SBR system uses more efficient aeration blowers and fine bubble diffused air (FBDA) configuration within each basin, while also removing the number of large automated valves required for isolation in batching.

[caption id="attachment_25323" align="alignnone" width="1200"] Sanitaire ICEAS Advanced SBR system - single basin segment - Courtesy of Xylem Water Solutions UK Ltd[/caption]

Power & automation

The volumes being treated are reflected with the scale of the power and control equipment on the new project. New 11kV supplies are being brought on to site, with new substations for the new and existing sites, supported with generator backup for resilience. Two large motor control centres (MCC) and kiosks have been designed and manufactured off-site using Design For Manufacture and Assembly (DfMA) to simplify and reduce on site installation work.

BIM modelling/Synchro

4D modelling was used in the early part of the design; utilising BIM 3D and Synchro modelling software integrated with Primavera 6 planning software. This assisted understanding of construction sequencing for the various disciplines and contractors, regarding large structures and equipment in a relatively restricted site.

[caption id="attachment_25320" align="alignnone" width="1200"] 3D model of off-site build main MCC/kiosk & steelwork - Courtesy of RSE Control Systems (GPS)[/caption] Avonmouth WRC Expansion Project: Supply chain - key participants Client: Wessex Water Principal designer & contractor: YTL Construction UK Designer for main works: AECOM Ltd Compound design: BIMTek Limited Document management support: Project Support Systems Enabling works/welfare: Envolve Infrastructure Piling contractor: Aarsleff Ground Engineering Electrical installation enabling works: OCU Group Ltd Office & welfare buildings: Wernick Group Formwork reinforcement & concrete: Carney Construction Over pumping: Pump Supplies Ltd SBR process: Xylem Water Solutions PST scraper bridges: Jacopa Ltd Submersible pumps: Xylem Water Solutions Submersible pumps: Grundfos Pumps Ltd SAS pumps: Vogelsang Ltd Washwater: KGN Pillinger Valve & penstock package: Cotswold Valves Ltd MCCs: RSE Control Systems (GPS) Flow controls: AFFCO Flow Control (UK) Ltd Flow meters: Siemens Ductile iron pipework: Saint Gobain PAM UK Access steelwork: GT Fabrications HV network & transformers: LC Power Ltd Generators: Addicott Electrics Ltd Concrete: Wright Readymix Specialist PST formwork: Special Formwork Reinforcement: Hy-Ten Ltd FRP bridge over Rhine Crossing: Janson Bridging Cranes: Select Plant Hire Progress to date (September 2025)

Enabling works

Due to the site’s geographical location, extensive unexploded ordinance surveys were carried out before clearing the site.

The enabling works package began in January 2024, delivered by framework partner Envolve Infrastructure under the management of YTL Construction, the principal contractor delivering Wessex Water’s largest treatment project. This included earthworks preparation and installation of a 90,000-tonne working platform.

[caption id="attachment_25326" align="alignnone" width="1200"] YTL Construction’s record single concrete pour - Courtesy of YTL Construction[/caption]

The working platform was quickly followed by the precast pile installation where up to five separate rigs were used to install almost 4,000 precast concrete piles to depths of up to 20m. The piling operation was undertaken by Aarsleff Ground Engineering.

The inlet represented one of the most complex areas to date. The existing structures date back to the 1960s and require modifications to facilitate diversion of flows to the new works.

To guarantee that the enabling works did not affect the inlet channel, comprehensive design, structural, and vibration assessments were conducted. This process also involved on-site testing of various technologies and methods for both sheet and precast piling to identify the most suitable solutions. Piling near the existing assets has been carried out without any problems.

The enabling works package also included the construction of a 2000m2 welfare and office building with carpark and associated services.

Major structures - PSTs & SBRs

Construction of the eight sequencing batch reactors began in August 2024 and is due for completion early 2026. The construction of the four primary settlement tanks began in September 2024 and is due for completion this year.

For the concrete bases, a 1500m3 pour was delivered in a continuous 16 hours - a new record for YTL Construction. This was only possible due to meticulous planning and collaboration with the supply chain.

Completion of the major structures will provide access to the remaining significant work areas, which will take a further 24-months of planning, resourcing and delivery.

[caption id="attachment_25325" align="alignnone" width="1200"] Construction progress of the SBRs - Courtesy of YTL Construction[/caption] Carbon savings

YTL Construction has been committed to reducing carbon from the concept of the scheme. A sustainability plan developed objectives and targeted areas that would drive this ambition. A detailed carbon calculation model baselined the design at feasibility and has been re-run throughout the period of design.

At completion of the detailed design and construction strategy stages, modelling confirmed that there would be carbon savings of 23% measured against the feasibility baseline thanks to a number of good initiatives that were being utilised on this project. A number of examples include:

Design optimisation (e.g. tapered concrete SBR walls). Selection of efficient plant (ie. pump selections and Xylem Water Solutions blower and FBDA technology). Design of aggregates and mixes (ie lower carbon concrete optimised mix design). Procurement selections (eg. lower carbon reinforcement steel). The offices and welfare buildings are a modular system which was purchased and refurbished, saving 40% on carbon, and 50% on manufacture lead time. The project selected a 22m long fibre reinforced plastic foot/pipe bridge against a more traditional carbon steel bridge, realising a 20% carbon reduction. Stakeholder engagement

Throughout the public and stakeholder consultation process, the project team spoke directly with the local community about the proposals at a series of drop-in sessions in Lawrence Weston, Shirehampton and Avonmouth.

More than 60 people attended across the three days, taking the opportunity to find out more about the plans, ask questions about the proposed expansion, as well as leaving their own comments and feedback. A virtual public consultation feedback form was also made available for comments.

The project team also visited local business events and extensively gauged the views of a wide range of organisations about the plans, including planning groups in Avonmouth, Lawrence Weston and Shirehampton to help shape the proposals. These were reported in a Statement of Community Involvement as part of the planning process, with conditional approval given by Bristol City Council planners in November 2023.

As a result of this extensive consultation process, and in tandem with the expansion, progress has been made on historical, environmental and biodiversity enhancements in and around the water recycling centre. These include measures to protect the Mere Bank Rhine, the Historic Scheduled Monument that runs between the existing site and the proposed development. Additionally, scrub clearance, planting of new habitats, and rerouting and revitalising existing public rights of way is being undertaken.

The project team has also completed volunteering days to help engage with the local community, including volunteering at the Avonmouth Food Bank to provide food parcels for families at Christmas, and community garden vegetation clearance in preparation for a well-being project.

[caption id="attachment_25328" align="alignnone" width="1200"] YTL project team at project commencement - Courtesy of YTL Construction[/caption] Conclusion

Eddie Rant, Director of Engineering & Asset Management with Wessex Water, commented:

“We’re incredibly pleased with how the project is progressing. To date, the YTL Construction team has demonstrated exceptional coordination, craftsmanship, and adherence to timelines. Communication has been clear and proactive and the quality of work so far gives us full confidence in a successful outcome. We’re excited to see the next phases unfold and grateful for the dedication shown by the team involved.’’

YTL Construction hope to provide an update to this article as construction nears completion, and again as commissioning concludes.

The requirement of the Burnley Integrated Catchment Scheme is the River Water Quality Improvement for the Water Framework Directive (WFD) driver identified in the Water Industry National Environmental Programme (WINEP) to achieve a ‘Good’ status in the defined reaches of Pendle Water and the River Calder. The project, which commenced in 2020, is one of United Utilities’ largest AMP7 investments and is being delivered by Advance-plus, a joint venture between MWH Treatment, J Murphy & Sons (JMS) and Stantec UK. In previous articles published by Water Projects, United Utilities has shared the project journey from concept, solution design development, and construction. This case study focuses on the project team’s experience in achieving effective project outcomes. Project requirements & summary

To meet ‘Good’ status in Pendle Water and the River Calder, the treatment capability at Burnley Wastewater Treatment Works (WwTW) had to be enhanced to achieve compliance with the new treated effluent permit standards, coupled with management of storm discharges in the defined reaches, to achieve compliance with the WFD 99%ile wet weather intermittent standards. There are eight regulatory drivers attached to this WFD element of the scheme.

The project also includes two additional regulatory drivers for U_MON3 spill monitoring and U_MON4 flow monitoring.

Through complex river water quality and network modelling, the lowest whole life cost integrated catchment solution was determined and developed.

The Integrated Catchment Solution comprised four sites, which are all inter-dependent in delivering the regulatory outputs.

[caption id="attachment_26729" align="alignnone" width="1200"] Modification of existing PSTs 6, 7, 8 and 9 - Courtesy of United Utilities[/caption] Burnley WwTW

Serving a domestic population equivalent of approximately 107,000 plus trade load, Burnley WwTW has undergone a significant upgrade during this AMP7 project with the scope comprising the design, construction, and commissioning of:

A new Evoqua BioMag® activated sludge plant (ASP) from Xylem Water Solutions. The BioMag® system enhances conventional biological wastewater treatment by using magnetite (an iron oxide powder) to ballast the microbiological floc, creating an increase in mixed liquor suspended solids (MLSS) in the ASP and enhanced performance in the final settlement tanks (FSTs). A new 64-panel, 12,000m3 detention tank constructed by A-Consult Ltd with associated feed pumping station. A new additional (4th) primary settlement tank. A new 2500 l/s interstage pumping station (pass forward of FtFT and RAS flows). Refurbishment of the four existing FSTs. A new surplus activated sludge (SAS) thickening process. A new ferric and caustic chemical dosing plants. New MCCs, SCADA upgrade and power upgrade. U_MON3 event duration monitoring on spills to storm tanks. U_MON4 flow monitoring.

The final effluent quality for the new works at Burnley WwTW is to comply with both WRA (spot samples) and UWWTD (composite samples):

Design Permit WRA Parameter Average 95% ile Upper Tier Limit BOD 9 mg/l 50 mg/l Solids 40 mg/l Ammonia 2 mg/l 12 mg/l Total P 0.25 mg/l Iron 4 mg/l 8 mg/l Design Permit UWWTD Composite Samples Parameter Compliance Requirement Upper Tier Limit BOD 25 mg/l (or 70% removal) 50 mg/l COD 125 mg/l (or 75% removal) 250 mg/l Total P 2 mg/l (or 80% removal) [caption id="attachment_26728" align="alignnone" width="1200"] Evoqua BioMag® activated sludge plant - Courtesy of United Utilities[/caption] Burnley WwTW Catchment Strategy: Supply chain - key participants Client: United Utilities Construction Delivery Partner: Advance-plus JV MWH Treatment (Advance-plus jv) J Murphy & Sons (Advance-plus jv) Stantec UK (Advance-plus jv) Civil design detention tank: COWI UK Ltd Physical modelling: Hydrotec Consultants Ltd Dewatering design: OGI Groundwater Specialists Ltd Dewatering: Alba Dewatering Services Ltd Concrete construction: STAM Construction Ltd Detention tank shaft: Joseph Gallagher Ltd Pump station shaft: EJ Kelly Sheet piling: Sheet Piling (UK) Ltd PCC driven piling: Van Elle Concrete cutting: Holemasters Temporary works/shoring: MGF Ltd Precast post tensioned tanks: A-Consult Ltd Precast roof sections: Macrete (Ireland) Ltd Precast shaft segments: FP McCann Blower building: Saredon Steel Buildings Ltd BioMag® building: Gallaway Construction Ltd Access metalwork: Tushingham Steel Fabricators Evoqua BioMag® process: Xylem Water Solutions BioMag® mechanical installation: Alpha Plus Ltd [caption id="attachment_26724" align="alignnone" width="1200"] Detention tank water test - Courtesy of United Utilities[/caption] Civils & pipework: SGC Civil engineering Ltd Pumping station mechanical installation: Fluid Sealing & Engineering (FSE) Transformers: Winder Power Electrical installation: PICOW Engineering Group MCCs: Technical Control Systems Ltd Systems integration: Tata Consultancy Services SAS glass coated steel tank: Stortec Engineering Ltd Dosing systems: NPS Engineering Group PST fixed scraper bridge: EPS Water Epoxy coated carbon steel pipework & wall starters: Freeflow Pipesystems Ltd SAS drum thickeners: Huber Technology Odour control system: Air-Water Treatments Ltd PST odour covers: Corporate Engineering Ductile iron pipework: Saint Gobain PAM UK Ductile iron pipework: Electrosteel Castings (UK) Ltd FST scraper bridge refurbishment: Jacopa Ltd Blowers: Sulzer Pumps Wastewater Ltd Aeration system: Suprafilt Ltd SAS tank air mixing system: Utile Engineering Submersible pumps: Xylem Water Solutions Valves: AVK UK Ltd Standby generators: DTGen Kiosks: Industrial GRP Ventilation: Air Technology Systems Ltd Lindred Road CSO (PEN0056)

Work at this existing combined sewer overflow (CSO) site comprised the construction of an online 1,950m3 detention tank to store storm waters during times of heavy rainfall and reducing discharges to the watercourse. New pumps within the tank return the effluent to the sewer for onward treatment at Burnley WwTW. A new MCC and power supply were installed for this facility.

[caption id="attachment_18286" align="alignnone" width="1200"] Lindred Road detention tank during construction - Courtesy of United Utilities & Advance-plus[/caption] Altham Outfall Fennyfold CSO (BUR0026)

This existing CSO site is located in the local town of Padiham and on the sewer network that transfers flows to Hyndburn WwTW for treatment. The solution at this site was to construct a new chamber over the downstream sewer, install a new ‘real time’ controlled actuated penstock valve that regulates and optimises flows passed forward to Hyndburn, whilst reducing spills from the existing CSO. A new control kiosk was also provided.

Hyndburn WwTW

Value engineering and engagement with the Environment Agency enabled a no-build solution to be accepted at Hyndburn WwTW site, with only the optimisation of existing storm tank emptying system necessary for compliance.

Process optimisation: update to previous report

New primary settlement tank No. 4

New primary settlement tank (PST) No. 4 desludge pump run/dwell timers have been optimised to provide primary sludge concentration to a target of ~3.5% ds w/w. Daily PST No. 4 sludge blanket dips are undertaken by ADP and UU Operations undertook routine measurement of primary sludge concentration to inform any occasional minor changes to desludge pump run/dwell timers. The set-points for the run/dwell timer of the PST No. 4 desludge pumps typically range from 9-12 minutes for the run phase and 45-60 minutes for the dwell phase. These set-points will be adjusted in the future to accommodate changes in operational conditions at the site, including those related to the current sludge treatment center. [caption id="attachment_26733" align="alignnone" width="1200"] PST4 with odour control cover - Courtesy of United Utilities[/caption] Interstage pumping station The new interstage pumping station (IPS) has been commissioned with close consideration of the operating level set-points as determined during detailed hydraulic design. Further optimisation of the recycled activated sludge (RAS) control flow rates was undertaken following an exceptionally dry and warm weather period during April-June 2025 which has then resulted in supplementary further optimisation of the IPS control set-points. To maintain a stable hydraulic gradient for control of RAS (via gravity) from the final settlement tanks, the IPS top water level has been further optimised at 2.5m set-point with an operating level set-point control band optimised across a 0.5m depth (as per design). The IPS pumps minimum/maximum operating speeds (32.5Hz and 50Hz respectively) have been further optimised to provide stable control to level set-point across the 0.5m operating level band and avoiding, as much as possible, pump start/stops during dry weather flow periods where pump minimum performance exceeds received flows into the pumping station. The IPS has operated generally in accordance with the initial duty/assist/assist cascading level control with PID control loop tuning set-points remaining generally unchanged since original turn of flows in early October 2024. Further optimisation of the IPS process control set-points is not envisaged in the future. [caption id="attachment_26725" align="alignnone" width="1200"] Interstage pumping station - Courtesy of United Utilities[/caption]

Process air blowers: The new process air blower package was initially commissioned with support from the supplier, Sulzer Water & Wastewater. The majority of operational set-points within the blower package system are standard defaults and did not require further optimisation. The assist blower start/stop changeover set-points were optimised during a subsequent Sulzer site visit to ensure stable operational transition, avoid unnecessary noise and prevent nuisance under/over pressure process trips.

The process air blower discharge header control set-point has been further optimised to 640 mbarg in attempt to minimise dissolved oxygen depletion during storm events. The occasional depletion of dissolved oxygen remains an issue during the extraordinary rate of change of incoming flows and loads often associated with these storm events.

The addition of alternative ‘Storm Mode’ process control may ultimately be required to fully remedy the situation. Further optimisation of the process air blower process control set-points may therefore be required in conjunction with implementation of future ‘Storm Mode’ process control philosophy.

New primary ferric sulphate dosing: Extensive and routine jar-testing to monitor the optimal primary ferric dose molar ratio dose to achieve target residual orthophosphate and Total Iron concentrations was undertaken during May and June 2025.

The primary ferric molar ratio dose providing optimal phosphate and iron control (~1mg/l orthophosphate and <20mg/l Total Iron concentrations in PST effluent), as determined during the Summer Completion Test, was 4.15 MR. For reference, the ‘as-commissioned’ diurnal orthophosphate base load profile is shown below.

[caption id="attachment_26740" align="alignnone" width="1200"] Burnley WwTW: Orthophosphate diurnal load profile - primary ferric LUT set-points (as commissioned November 2024) - Courtesy of United Utilities[/caption]

A summary of initial and subsequent primary ferric dosing MR dose ‘optimisation’ is provided below:

28 November 2024 Dosing commences at 5MR 11 December 2024 Dosing increased to 6MR to target 1mg/l orthophosphate in PST effluent 20 December 2024 Dosing reduced to 5MR in response to ASP ammonia breakthrough spikes 24 December 2024 Dosing reduced to 4MR in response to ASP ammonia breakthrough spikes 2 January 2025 Dosing paused in response to observed ASP ammonia breakthrough spikes 9 January 2025 Dosing recommenced at 2MR 11 February 2025 Dosing increased to 3MR to target 1mg/l orthophosphate in PST effluent 25 February 2025 Dosing increased to 3.5MR to target 1mg/l orthophosphate in PST effluent 6 March 2025 Dosing increased to 3.75MR to target 1mg/l orthophosphate in PST effluent 17 March 2025 Dosing reduced to 3.5MR in response to ASP ammonia breakthrough spikes 24 April 2025 Dosing increased to 3.75MR to target 1mg/l orthophosphate in PST effluent 30 April 2025 Dosing paused in response to observed FST iron breakthrough spikes 3 May 2025 Dosing recommenced at 4.5MR following jar testing 8 May 2025 Dosing reduced to 4.15MR in response to jar test results N/A No primary ferric MR change since 8/5/25

Routine, minor, operational changes to the primary ferric dosing set-points will remain a business-as-usual activity associated with normal wastewater treatment works operation in the future; and most notably, in response to envisaged seasonal variation and catchment characteristics.

Caustic dosing: An initial set-point of 7.1 pH units was adopted for interstage pH process control upon commencement of the Summer Completion Test. This control set-point has been further optimised on occasion and in agreement with/request by United Utilities Operations to 7.15 pH units to either reduce chemical consumption or in consideration of prevailing final effluent alkalinity measured value.

Routine, minor, operational changes to the interstage pH setpoint considering prevailing final effluent pH and alkalinity will remain a business-as-usual activity associated with normal wastewater treatment works operation in the future.

[caption id="attachment_26726" align="alignnone" width="1200"] Chemical dosing area - Courtesy of United Utilities[/caption]

Liquid polyelectrolyte dosing: The ‘sweetening’ dose set-point of 25 l/h per FST has been retained and a storm event %FtFT trigger setpoint of 75% (in line with Evoqua recommendation). During periods of low FtFT, the 25 l/h ‘sweetening’ dose set-point results in the liquid poly system batching around four times per day; ensuring that a fresh, but matured, make-up solution is available at all times in readiness for flash increase in FtFT or prolonged storm event.

The poly dose proportional set-point has been gradually reduced to the current value of 0.6 mg/l as active product. It is noted that the product selection and amount of liquid polyelectrolyte dosed is subject to EA permitting and, as such, strict limits on maximum poly dose rate applies (currently 3.2 mg/l maximum as active product).

Further optimisation of the liquid poly ‘proportional’ dose process control set-points is not envisaged as necessary in the future.

[caption id="attachment_26734" align="alignnone" width="1200"] New assets at Burnley WwTW - Courtesy of United Utilities[/caption]

Magnetite addition & recovery: Magnetite, an iron oxide powder, is added to the activated sludge process via the BioMag® system to provide mixed liquor enhanced settleability in the final settlement tanks by microbiological floc ‘ballasting’.

The new works was operated during Q1 of 2025 to maintain the magnetite : MLSS ratio at the target of approximately 2:1, which was necessary to achieve the necessary mixed liquor settleability performance as measured by Specific Stirred Volume Index (SSVI).

Control to the target ratio is effected by management of magnetite ‘top-up’ addition, and in consideration of daily surplus activated sludge wastage volume, which relies upon having a disposal route for SAS. Mixed liquor settleability performance matured naturally during Q2 of 2025 and the magnetite : MLSS ratio was coincidentally reduced to target of 1:1 by the reduction of magnetite ‘top-up’ addition to the design anticipated amount of 500 to 600 kg/d.

The historic magnetite : MLSS ratio data is shown in the graph below. It can be seen that magnetite : MLSS ratio has trended down since the Summer Completion Test and as such, the ‘top-up’ magnetite loading set-point has been increased slightly to compensate.

Routine operational changes to the daily magnetite loading rate will therefore remain a business-as-usual activity associated with normal wastewater treatment works operation in the future. [caption id="attachment_26722" align="alignnone" width="1200"] MLSS minus magnetite (true MLSS) and true MLSS : Magnetite ratio on-site tests and laboratory results - Courtesy of United Utilities[/caption]

Recycled activated sludge control: Further optimisation of the RAS control set-points was undertaken following the extended period of exceptionally dry and warm weather period during April-June 2025. During this dry weather period the RAS flow rate was maximised to design limitation of 1,040 l/s to best manage potential for denitrification within the FSTs and avoid rising sludge and scum formation where possible. RAS control to ‘FtFT Mode 1’ was adopted for control of RAS flows during the Summer Completion Test in accordance with a three-tiered banded philosophy as follows:

FtFT flow (l/s) RAS flow (l/s) <600 400 >600 <1000 600 >1000 750

The RAS control system has operated stably for many months, and no significant further optimisation is envisaged. However, routine operational changes to the RAS control rate or mode of operation will remain a business-as-usual activity associated with normal wastewater treatment works operation in the future.

Activated sludge plant: Routine control of MLSS concentration has remained by the conventional method of monitoring food to micro-organism ratio (F/M) to the design target ~0.08d-1, by assessment of sludge age against target of ~14 days and then by manual adjustment of the surplus activated sludge daily wastage volume.

Routine monitoring of the biological load on the ASP and as-required operational changes to the daily SAS wastage volume to maintain F/M ratio and sludge age within an acceptable range will remain a business-as-usual activity associated with normal wastewater treatment works operation in the future. The historic F/M ratio and sludge age data is shown below.

[caption id="attachment_26739" align="alignnone" width="1200"] F to M ratio and sludge age - Calculated using on-site tests and laboratory test results - Courtesy of United Utilities[/caption]

Similarly, routine microscopic analysis has been undertaken by UU labs to monitor and track filamentous (and other indicator bacteria) abundance.

Summary/conclusion

The Summer Completion Test was carried out by Advance-plus over a 28-day period between 21 July and 18 August 2025. From the test results, it is concluded that the new works has successfully demonstrated compliance with the requirements of:

CT1: Final effluent water quality compliance with site WRA Regulatory Permit limits for BOD, TSS, ammonia, Total Phosphorus, Total Iron and pH. The final effluent water quality adequate compliance with asset standard for alkalinity residual (noting routine pH set-point change made during completion test in response to slight reduction in background alkalinity). CT2: Final effluent water quality compliance with site UWWTD Regulatory Permit limits for BOD and COD. CT3: Final effluent water quality compliance with site UWWTD Regulatory Permit limits for Total Phosphorus. CT4: Magnetite recovery rate of the BioMag® process.

Ballina WwTP is located in the existing urban area of Ballina Town, roughly 100m from the border between County Tipperary and County Clare. The facility is an asset of Uisce Éireann (formerly Irish Water) and it is currently operated by Tipperary County Council (TCC) on behalf of Uisce Éireann under an existing Service Level Agreement. It serves both the Ballina and the Killaloe agglomerations and was officially opened in August 1996. It was initially designed to treat flows generated from population equivalent (PE) of 4,000. Project need

The current population associated with the WwTP has been assessed at 5,400 PE, which is more than the current design capacity (4,000 PE). This population is estimated to increase to 8,000 PE in the +10 year design horizon and to 8,400 PE in the +25 year design horizon. Therefore, it was necessary to increase the treatment capacity of the WwTP to meet the current and increasing population within the agglomeration.

The WwTP discharged treated effluent via the primary discharge point to the Grange River. The discharge limits set out by the EPA Discharge Licence were not being met in relation to the BOD and ammonia limits.

[caption id="attachment_15770" align="alignnone" width="1200"] Construction work underway at Ballina - Courtesy of Shay Murtagh Precast[/caption]

The WwTP was an extended aeration activated sludge plant. There was no excess influent management system in place and as such, all flows entering the plant were passed forward to the process tanks. All flows entering the WwTP received the following levels of treatment:

Preliminary treatment in the form of screening and grit removal. Secondary treatment in the form of two oxidation ditches and two final settlement tanks. Tertiary treatment in the form of a ferric dosing system to aid in phosphorus removal.

The waste sludge generated at the WwTP was stored and thickened on site within a picket fence thickener (PFT). As the existing dewatering facilities on site were no longer in operation, the waste sludge produced on site (approximately 90 tonnes/week) was pumped from the PFT to a tanker and removed from site.

[caption id="attachment_15774" align="alignnone" width="1200"] New inlet works under construction - Courtesy of Ward & Burke[/caption] Scope of works

Ward & Burke was appointed by Uisce Éireann in December 2022 as the Main Contractor to upgrade the existing plant, providing design, civil engineering, plant operations and MEICA works for the contract.

The purpose of the contract was to upgrade the Ballina WwTP to provide sufficient treatment capacity for the target design horizon and to meet the required effluent discharge limits set out in the EPA Discharge Licence. The works included the design, supply, installation, testing, commissioning and handover of the upgraded plant. The existing WwTP remained operational during the construction works with minimum interruptions to the operation of the existing process stream.

The works included for the provision of operation and maintenance (O&M) of the existing Ballina WwTP during the design build and O&M of the upgraded plant for 365 days following commissioning.

The scope of Ward & Burke’s design and build works included:

Construction of a new below-ground forward feed pump station and stormwater overflow (SWO), to lift incoming wastewater to new inlet works and allow excess flows towards the new storm tank. Construction of a new above-ground inlet works structure comprising: Duty/standby 6mm fine screens. 19mm bypass screen. Grit removal unit. Grit classifier. Screening handling unit. Storm overflow and flow splitting chamber to split flows between the new and existing streams. Construction of a new below-ground stormwater storage tank along with associated pumps, meters and pipework. Decommissioning of the existing inlet screens and grit removal works. Construction of a new below ground circular aeration tank. Installation of new duty and stand-by blower units for the proposed diffuser aeration system. Construction of a new below ground final settlement tank. [caption id="attachment_15773" align="alignnone" width="1200"] New final settlement tank under construction - Courtesy of Ward & Burke[/caption] Scope of works (continued) Construction of a new below-ground return activated sludge/waste activated sludge (RAS/WAS) pump sump and associated duty/standby pump set to facilitate sludge handling from the proposed new process stream. Construction of a new above ground picket fence thickener. Relocation of the existing outfall to a new treated effluent outfall to the Lough Derg which also incorporates the overflow from the new stormwater storage tank. Additional motor control centre (MCC) to facilitate the new stream. SCADA upgrade resulting from additional works elements and decommissioned existing elements. Ancillary works associated with the telemetry and control of the new process stream in combination with the existing infrastructure. Connection of the new stream to the existing infrastructure to facilitate testing and commissioning while the existing infrastructure remains live. Provision and installation of permanent and appropriate energy monitoring equipment to facilitate energy monitoring and verification of the design and operation of the works. [caption id="attachment_15772" align="alignnone" width="1200"] New storm water tank under construction - Courtesy of Ward & Burke[/caption] Ballina WwTP: Supply chain - key participants Civil/process design & project delivery: Ward & Burke Employers representative: RPS Resident engineer: Nicolas O’Dwyer Precast tanks: Shay Murtagh Precast Precast chambers: Tracey Concrete Ductile iron pipe and fittings: Fusion Pipeline Products Odour control: John Cockerill Environmental Grit removal & storm/inlet screens: Jacopa Aeration blowers: Aerzen Machines Diffused aeration system: SSI Aeration PVC pipe: Total Pipeline Specialists (TPS) MCC: Ward & Burke Construction Ltd Access covers: EJ Ireland Pumps, mixers, fine bubble diffusers: Sulzer Pumps Wastewater Ltd Flow meters: Siemens Ultrasonic meters: Pulsar Measurement Flow switches: IFM Electronics Penstocks: Talis Valves: Valve & Actuator Solutions Ltd Actuators: Auma Actuators Ltd Kiosks: Gleeson Steel & Engineering FST scrapers & site-wide metalwork: Keltec FST scrapers & site-wide metalwork: D&E Welding FE service water boosters: Campion Pumps Lifting equipment: T Allen Engineering Services Ltd Civil engineering works The major civil elements of work on the Ballina WwTP project and the outline construction methods are shown in the following table: Work element Construction Methodology Work element Construction Methodology Storm tank Below-ground precast concrete tank Forward feed PS Below ground in situ caisson Aeration tank Below-ground precast concrete tank RAS/WAS PS Below ground precast chamber FST Below-ground precast concrete tank Wash water PS Below ground precast chamber PFT Above-ground precast concrete tank 450mmØ outfall Float/sink outfall pipe in pre-dredged trench Process technologies/innovations 6mm MEVA step screens have been installed on this project which exclude the need for process washwater resulting in a carbon footprint saving. An air lift grit removal system has been employed which consists of stainless-steel coarse bubble diffuser system along with a stainless-steel grit lift pipes. This system ensures there is no moving parts submerged in the tank allowing all maintenance required to be carried out without the need to enter the tank. A fine bubble diffused aeration system has been supplied by SSI Aeration. The 9” fine bubble diffusers have got one of the best oxygen transfer efficiencies on the market. A final effluent washwater system has been designed to utilise the final effluent from the plant as wash water on inlet works launders, grit classifier and Washpactor. This means treated potable water is not required to be used, thus ensuring a better carbon footprint. The system consists of a buffer tank and a set of booster pumps and associated valving and pipework. Key challenges

Some of the key challenges on the Ballina WsTP project included:

The project took place on a live treatment plant, which had to remain fully operational during construction. The works, including the construction of the outfall, took place in, and adjacent to, a major watercourse (the River Shannon) as well as the Grange river, with historical liability to flooding. The project scope required the construction of large underground structures up to 5m below ground in silts and gravels with potentially variable groundwater behaviour due to the presence of the Shannon, Mill and Grange Rivers. [caption id="attachment_15775" align="alignnone" width="1200"] New outfall under construction - Courtesy of Ward & Burke[/caption] Conclusion/summary

The design and build project to upgrade the Ballina WwTP is due to be commissioned in October 2024; after 550 days. The upgrade will bring benefits to Killaloe and Ballina including ending the discharge of poorly treated effluent, improving water quality in the receiving waters, and enhancing local amenities and a platform for social and economic development.

The project also accounted for forecast future population growth of the surrounding areas and ensuring compliance with the Urban Wastewater Treatment Directive and EPA Wastewater Discharge Licencing.

The Burnley integrated catchment scheme is one of United Utilities' (UU) largest AMP7 projects with a value of £77m. The project is being delivered by UU’s construction delivery partner (CDP) framework by Advance-plus, a joint venture between MWH Treatment, J Murphy & Sons (JMS) and Stantec UK. The project commenced in 2020 and through two previous articles, UU and Advance-plus have shared the project background, the story of developing the solution and design, and commencing the build. In this year’s article, the project delivery team is pleased to provide an update on the construction progress and a look at the journey ahead as the project remains on course to achieve the December 2024 regulatory completion date. A summary of the project requirements and the integrated catchment solution scope The integrated solution scheme requirement is River Water Quality Improvement for the Water Framework Directive (WFD) driver identified in the Water Industry National Environmental Programme 3 (WINEP3) to achieve a ‘good status’ in the defined reaches of Pendle Water and the River Calder. To meet this, the treatment capability at Burnley Wastewater Treatment Works (WwTW) is to be enhanced to achieve compliance with the new enhanced, treated effluent permit standards, and management of storm discharges in the defined reaches, to achieve a compliance with the WFD 99%ile wet weather intermittent standards. The project also includes the U_MON3 spill monitoring and U_MON4 flow monitoring drivers. Through complex river water quality and network modelling, the lowest whole life cost integrated catchment solution was determined and developed. Four sites make up the integrated catchment solution which are all interdependent in delivering a total of ten regulatory outputs. [caption id="" align="alignnone" width="1200"] ASP under construction - Courtesy of United Utilities[/caption] Burnley WwTW Burnley WwTW serves a domestic population equivalent (PE) of 107,115 plus trade load. The site is undergoing a significant upgrade with the scope comprising design, construction, and commissioning of: New 12,000m3 detention tank with associated pumping station. New additional primary settlement tank (PST). New 1300 l/s inter-stage pumping station. New activated sludge plant (ASP) with BioMag® process. The BioMag® System enhances conventional biological wastewater treatment by using magnetite (Fe3O4) to ballast floc allowing an increase in mixed liquor suspended solids (MLSS) in the ASP and enhanced performance in the final settlement tanks (FSTs). Refurbishment of existing final settlement tanks. New surplus activated sludge (SAS) thickening process. New ferric and caustic dosing plants. Associated motor control centres (MCCs), SCADA upgrade, and power upgrade. Pipework The last year has seen great strides being made across the site and various process areas, with major civils structures constructed and taking shape. The very constrained nature of the site, existing processes and services, and the need to lay many kilometres of small and large diameter underground pipework has proven to be a major constructability challenge. Most of the pipework installation has been self-delivered by J Murphy & Sons with Saint Gobain PAM UK being the main supplier of the pipework and fittings. Detention tank The new detention tank, has been constructed by A-Consult Ltd using 64 precast concrete panels, standing 10.4m high. The panels were precast in their factory before being transported to site for erection and subsequent post tensioning. Utilising this construction technique, with design for manufacture and assembly (DfMA) brings benefits in terms of quality, time and safety. The tank has successfully passed its water test and is currently being drained. The feed pumping station has been constructed and the mechanical installation of pumps, mixers and pipework is now in progress. [caption id="" align="alignnone" width="1200"] Detention tank on water test - Courtesy of United Utilities[/caption] Primary settlement tank The new primary settlement tank (PST) civils construction is also complete, again undertaken by A-Consult Ltd using the precast concrete panel method of construction. It has also successfully passed its water test. Mechanical installation by EPS Water is now in progress on the ‘H’ frame steel structure which will support the scraper bridge. The design of the PST incorporates a fixed bridge arrangement with rotating scrapers beneath. This arrangement is necessary as the PST will eventually be covered with a GRP roof for odour mitigation. The odour control fans, ductwork and vent stack are scheduled to be installed in December. [caption id="" align="alignnone" width="1200"] PST4 and ASP lane 1 on water test - Courtesy of United Utilities[/caption] Interstage pumping station Due to the topography and hydraulic levels across the site, a new interstage pumping station (IPS) is required to pump the effluent leaving the four PSTs up to the new activated sludge plant (ASP) distribution chamber. Civils FRC works are being undertaken by STAM Construction Ltd and contain 94 tonnes of rebar and 900m3 of in situ poured concrete. The pumping station structure is complete and has undergone successful water testing. The internal benching is complete and the next activities planned for the coming period will be the mechanical installation of the pumps and pipework. As the pumping station is vital to keep all flows passing through the treatment process, a standby generator will also be installed. The IPS is a two compartment design to facilitate future maintenance activities preventing the need to take it completely out of service. The new pumps have been supplied by Xylem Water Solutions who have supported the designers in providing efficient selections for the large submersible pumps and optimising the layouts of the pump chambers. Activated sludge plant The ASP distribution chamber is currently being constructed with all four concrete walls having now been poured. These are curing and the structure will undergo a water test in September 2023. [caption id="" align="alignnone" width="1200"] ASP constructed and water tested - Courtesy of United Utilities[/caption] In constructing the new ASP, STAM Construction Ltd have installed 650 tonnes of rebar and poured 4500m3 of concrete. The overall size of the ASP is 48m x 48m x 6.6m deep, has a capacity of 14,500m3 and comprises four lanes. Civils construction of the ASP is complete and fully water-tested with the mechanical installation of the internal pipework, aeration grids, diffusers and access platforms and walkways taking place over the next few months. Suprafilt Ltd will be supplying and installing the internal pipework, aeration grids and diffusers. Mechanical installation of the pump stations and access steelwork etc will be undertaken by Fluid Sealing & Engineering (FSE). BioMag® The Evoqua Water Technologies detail design for the new BioMag® process has been finalised and the building layout confirmed. The main equipment including four Magdrums and two shear mills, process tanks, silo and pumps, which have been manufactured and are ready for delivery to site when required. The BioMag® building is currently under construction by Gallaway Construction. The steel frame has been erected and the gantry crane and roof cladding have been installed. External wall cladding is in progress, after which attention will turn to the internal fit-out and installation of the BioMag® equipment. [caption id="" align="alignnone" width="1200"] BioMag® building being erected - Courtesy of United Utilities[/caption] Final settlement tanks (FST) There are four existing final settlement tanks which required refurbishing to ensure adequate performance and asset life are achieved. The scope includes civils refurbishment of the tank walls which involves cutting approximately 300mm from the top of the walls before installing new reinforcement and re-casting concrete to the required coping levels. Cutting works is being undertaken by Holemasters and FRC works self-delivered by JMS. The mechanical and electrical work is being delivered by Jacopa and comprises refurbishment of the bridge, scraper assemblies, and other ancillary equipment. Three of the four FSTs have now been refurbished with the final one due to be undertaken towards the end of the year. Surplus activated sludge (SAS) thickening Civils works has been ongoing in the SAS thickening process area for the last couple of months with the storage tank, drum thickener, poly plant and kiosk bases all constructed. Underground services, ducts and pipework have also been installed and tested. The filtrate return pumping station construction is in progress with the mechanical installation due to follow on. Chemical dosing The new ferric and caustic dosing plants comprise storage tanks, dosing rigs and dosing pipelines, all of which have been designed and well progressed in manufacture. These are being supplied by NPS Engineering Group. A new chemical delivery facility will also be provided with civils construction in this area commencing towards the end of the year and installation of the new dosing plants taking place early 2024. [caption id="" align="alignnone" width="1200"] 3D model of chemical dosing area - Courtesy of United Utilities[/caption] HV works A new, uprated HV cable has been installed from the off-site substation to the wastewater treatment works, a length of approximately 900m, passing through a number of fields and third-party land. Motor control centres (MCCs) To control all the new assets a number of new MCCs housed within kiosks are required around the site, along with a new site-wide SCADA system. The MCCs are all in various stages of manufacture and factory testing. The electrical installation and system integration works, including dry testing, will be undertaken in phases over a period of months as the programme for each of the new process areas dictates. The MCCs are being built by Technical Control Systems Ltd, electrical installation will be by PICOW Engineering Group and system integration by Tata Consultancy Services. Looking forward to commissioning Commissioning of the new treatment process, and transitioning from the old process in a controlled staged approach, will be complex. The existing treatment stream and process compliance cannot be put at risk or compromised and months of hard work and planning for commissioning has already taken place. Wet commissioning is due to start in April 2024, gradually increasing flows into the new treatment process over several months while the new biological process builds up and matures to a point where the improved treatment standards are being met. The forecast project in use date is October 2024. [caption id="" align="alignnone" width="1200"] Aphex construction planning software map view - Courtesy of United Utilities[/caption] Burnley WwTW Catchment Strategy: Supply chain - key participants Construction Delivery Partner: Advance-plus JV MWH Treatment (Advance-plus jv) J Murphy & Sons (Advance-plus jv) Stantec UK (Advance-plus jv) CFD modelling: CER Technologies Ltd GPR & topo surveys: Atlantic Geomatics (UK) Ltd Flood risk assessment: Ambiental Environmental Assessment Ltd Physical modelling: Hydrotec Consultants Ltd Dewatering design: OGI Groundwater Specialists Ltd Concrete construction: STAM Construction Ltd Concrete supply: CEMEX UK Pump station shaft: EJ Kelly Sheet piling: Sheet Piling (UK) Ltd PCC driven piling: Van Elle Concrete cutting: Holemasters Temporary works/shoring: MGF Ltd Precast post tensioned tanks: A-Consult Ltd Earthworks: D Morgan plc Blower building: Saredon Steel Buildings Ltd Access metalwork: Tushingham Steel Fabricators BioMag process: Evoqua Water Technologies (Xylem Water Solutions) BioMag building: Gallaway Construction Ltd BioMag mechanical installation: Alpha Plus Ltd Ventilation: Air Technology Systems Ltd Pumping station mechanical installation: Fluid Sealing & Engineering (FSE) HV cable installation: Smith Brothers Ltd Transformers: Winder Power Electrical installation: PICOW Engineering Group MCCs: Technical Control Systems Ltd Systems integration: Tata Consultancy Services Standby generators: DTGen SAS glass coated steel tank: Stortec Engineering Ltd PST fixed scraper bridge: EPS Water Epoxy coated carbon steel pipework & wall starters: Freeflow Pipesystems Ltd Dosing systems: NPS Engineering Group SAS drum thickeners: Huber Technology Odour control system: Air-Water Treatments Ltd PST odour covers: Corporate Engineering Ductile iron pipework: Saint Gobain PAM UK Ductile iron pipework: Electrosteel Castings (UK) Ltd FST scraper bridge refurbishment: Jacopa Ltd Blowers: Sulzer Water & Wastewater Aeration system: Suprafilt Ltd SAS tank air mixing system: Utile Engineering Submersible pumps: Xylem Water Solutions Valves: AVK UK Ltd Kiosks: Industrial GRP Lindred Road CSO (PEN0056) Work at this existing combined sewer overflow (CSO) site comprises the construction of an online 1,950m3 detention tank which will hold stormwater during times of heavy rainfall, reducing discharges to the watercourse. New pumps within the tank will return the effluent to the sewer for onward treatment at Burnley WwTW. The 15m diameter x 20m deep detention tank, is of segmental shaft construction and is located within the very busy and congested Lomeshaye Industrial Estate in Nelson, and was constructed by Joseph Gallagher Ltd. This was a highly challenging build within a car park of one of the local businesses and an enormous amount of planning and stakeholder management has been required. [caption id="" align="alignnone" width="1200"] Lindred Road detention tank during construction - Courtesy of United Utilities[/caption] Work started on site in July 2022, with the first phase involving the diversion of numerous services, including gas, fibre, BT, water and power, to clear the area for the tank construction. Enabling works to provide safe access routes, segregation, and procurement of alternative car parking for the impacted business employees was also required before the main construction work could commence. Ground was broken in August 2022 with the tank construction continuing through to December 2022 when full depth was reached. Construction of the pump sumps, inlet channel and complex benching arrangement followed. The spring months of 2023 saw the mechanical works inside the tank take place with the installation of the pumps, pipework and access ladders and platforms. Once the internal works were complete, the roof beams were installed and the roof slabs placed on in May 2023. The inlet and outlet pipework for the tank has now been installed, including associated manholes and chambers. To facilitate the connection of the 1200mm inlet pipe into the existing CSO chamber, a complex timber heading arrangement needed to be constructed in order to access beneath, and protect a myriad of services crossing the vicinity. All buried pipework, chambers and ducts etc have been completed and reinstatement of the area is in progress. The civils and pipework has been undertaken by SGC Civil Engineering Ltd and the mechanical works by Fluid Sealing & Engineering (FSE). A new motor control centre and power supply is being installed for this facility. The new control kiosk was delivered and installed in July 2023 and the electrical installation is currently ongoing with the new power supply due to be energised in October. Testing and commissioning is scheduled to start in November, with the site achieving project in use in February 2024. Lindred Road Detention Tank: Supply chain - key participants Civil design detention tank: COWI UK Ltd Detention tank shaft: Joseph Gallagher Ltd Civils & pipework: SGC Civil engineering Ltd Mechanical works: Fluid Sealing & Engineering (FSE) Precast roof sections: Macrete (Ireland) Ltd Precast shaft segments: FP McCann MCCs: Technical Control Systems Ltd Kiosks: Industrial GRP [caption id="" align="alignnone" width="1200"] Lindred Road: Aerial view of detention tank - Courtesy of United Utilities[/caption] Altham Outfall Fennyfold CSO (BUR0026) This existing CSO site is located in Padiham, near Burnley, and is part of the sewer network that transfers flows to Hyndburn WwTW for treatment. The solution here is to construct a new chamber over the downstream sewer, and install a new real time controlled actuated penstock valve that will regulate and optimise flows passed forward to Hyndburn, whilst reducing spills from the existing CSO. A new control kiosk and power supply are also required. This new facility is situated within an environmental and stakeholder sensitive area, adjacent to a number of allotments and the River Calder. The parcel of land required for the new kiosk and chamber has been procured and a new access track for future operation and maintenance, as well as the build, will be required and constructed. The detailed design is complete and some enabling works to set up site have been undertaken. For the main construction activity, a complex temporary works arrangement will be required, with large scale over-pumping, to carry out the works on the live sewer. Plans are currently being made to install temporary isolation rails and plates during a suitable dry weather period in preparation. This site is scheduled to be complete in spring 2024. Hyndburn WwTW To cater for the change in flows being presented at Hyndburn WwTW through the inlet sewer from the BUR26 catchment, the solution modelling has identified that by reducing the time it takes for the storm tanks to be returned into the treatment stream would ensure that the river water quality objectives could be achieved. The existing storm return pumping station is made up of fixed speed pumps operating at a duty of 100 l/s. A new variable speed storm return pumping station will be constructed which will be capable of returning flows across the range of 30 l/s to 330 l/s. This means that the contents of the storm tanks can be returned much quicker after a storm subsides. [caption id="" align="alignnone" width="1200"] Hyndburn WwTW - 3D model of storm return pumping station - Courtesy of United Utilities[/caption] A new below-ground wet well type pumping station will be constructed with three high-flow pumps and two low-flow pumps which provides a more flexible and efficient system with greater turn down capability. A new single rising main will return the storm flows back to the head of the treatment works. A new kiosk and motor control centre will also be installed. Planning permissions are in place and all pre-start surveys and investigations have been completed. Detailed design is nearing completion and the site has just been established. Construction is due to start in earnest in September on the new pumping station excavation. The winter months will see the civils works progress, with mechanical and electrical works due to start in spring. The project in use is forecast for July 2024. The digital toolbox 4D digital rehearsals which link the 3D model to the programme have been used extensively by the site team to validate the constructability and sequencing of the works. Visualisation allows all parties to truly understand the construction sequence, interfaces and interdependencies which is relevant on such a congested work area with multiple subcontractors operating in close proximity. They have helped to identify high risk activities and plan mitigation measures. They also help provide programme and cost certainty and facilitate stakeholder engagement. Over the last year Aphex, a powerful construction planning software tool which enables the delivery teams to better plan and work together has been introduced. This has been used for short term, look-ahead planning, which is linked to, and aligned with the master schedule in P6. It has also enabled the construction teams to control the build, assign ownership, communicate and track plans on a daily basis. [caption id="" align="alignnone" width="1200"] Aphex construction planning software Gantt chart - Courtesy of United Utilities[/caption] Challenges and collaboration A large and complex project of this type, across several sites, brings enormous and numerous challenges. These include health and safety management of large scale, complex construction in constrained working areas, on live operational sites and in 3rd party and public areas, while also working in environmentally sensitive areas and requiring engagement and interfacing with customers. Successful delivery would not happen without true collaboration. From the outset of the project we delivered a team development programme and established a co-located office which has proven to be invaluable in creating a great culture and an open and collaborative working environment over the last three years. Challenges and emerging risks and issues are dealt with almost on a daily basis as a team. The project teams continually work together to ensure that delivery stays on track, the highest standards are maintained and everyone goes home safe and well.

Tertiary Solids Removal (TSR) on small rural sites is growing in demand as phosphorus and iron consents are applied. For these smaller, remote works, additional consents, new or tightened, can lead to the overall upgrade requirements which can be difficult to execute due to economic viability and process challenges related to the low flow rates found at facilities with lower population equivalents. These challenges can include power availability and the need for site power upgrades, land availability and the need to compulsory purchase, and the hydraulic capacity of the site and the need for attenuation to cope with the backwash volumes from traditional TSR solutions. Background

The assertion of uneconomic viability is becoming harder to argue as more sites are having ever tightening consents applied to them, meaning that the offsetting of better performance from larger sites is being negated, and these smaller sites are having to be upgraded to meet the consents and catchment area water quality targets.

AquaPyr filter

The AquaPyr filter from ACWA Services has been designed to negate these CAPEX upgrade costs and issues as far as possible but still deliver a cost-effective, robust solution in providing tertiary solids removal for remote rural treatment works ensuring discharge consents are met.

[caption id="attachment_15485" align="alignnone" width="1200"] AquaPyr Model 440 - Courtesy of ACWA Services[/caption]

Traditional cloth media filters typically generate between 2% and 5% of forward flow volumes as backwash water according to manufacturers data. However, these figures are based on higher flow works and do not scale downward when applied to smaller WwTPs.  It is not uncommon to have 15 to 20% of the forward flow utilised as backwash water and returned to the plant in smaller works or applications with higher TSS, such as filtration of chemically dosed feed for reduction of Total P. These high levels of backwash water being returned to the head of works can cause potential ‘flooding’ of the works as many are already close to their hydraulic capacity, resulting in the need for the construction of backwash balance tanks to control this additional flow being added to the works.

Low flow sites pose additional problems for traditional backwash cloth filters, as often flows are insufficient to generate the required waters for backwashing at low flow rates, such as summer months, when the need for chemical dosing for phosphorus removal is likely to be at its greatest with the resulting increase in solids that need to be removed prior to final discharge. This can result in maintenance issues for the filters or the need to build baffle tanks to hold sufficient water for the backwashing requirements during periods of low flow, again increasing CAPEX in the building of these and OPEX of the solutions with increased pumping requirements.

The ACWA AquaPyr filter is an innovative fully contained, deep pile cloth media filter that generates minimal waste during the filter cleaning process. This is possible as unlike traditional TSR filters, the AquaPyr filter uses a patented air driven cleaning process in place of water for backwashing the filter, thus eliminating the need to store water for backwashing and then attenuating used backwash water for return to the front of the works. Typical waste volumes per clean are between 4 litres and 50 litres depending on the size of the unit, and remain <0.25% of forward flow.

This resulting waste is of a relatively high solids concentration, as much as 2% dry solids (DS), meaning that this could be discharged to the sludge or humus tanks rather than returning to the head of works and putting extra loading stress on the works.

The AquaPyr filter comes in a range of sizes meaning treatment volumes of a single unit range from 0 to 2000m3/day dependent on the solids loading applied to the filter. Multiple units can be used in parallel to increase these volumes and provide duty standby resilience as required.

[caption id="attachment_15488" align="alignnone" width="1200"] The AquaPyr Ultra Low Waste Filter product range - Courtesy of ACWA Services[/caption]

The units are fully self contained and all the pumps, drives and vacuum motors required for the operation of the unit are fitted internally. With a footprint range of 750mm x 710mm for a Model 25 up to 1960mm x 1770mm for a Model 440, the units have a uniquely small footprint for their treatment capacity.

The units low power draw and power requirements, ranging from 11 Amps for a Model 25 to 40 Amps for the Model 440 mean that all units are single phase, with the Models 25 and 65 actually being able to be used on a domestic three pin plug. AquaPyr filters consume little power; across all models power consumption averages in the range of 7 to 10 kWh/1000m3 of feed.

Case study: Silver Lake WwTW, Indiana

AquaPyr’s compact filter size, robustness and low operational costs led to Silver Lake, a small rural community in Indiana, choosing to use the technology on their unmanned sites. The Silver Lake WwTW is an activated sludge works with a design flow of 1.6 l/s.

The effluent entering the filter had 10 mg/l total suspended solids and a BOD of 10 mg/l. The requirement was for <=0.5mg/l Total P.

Two ACWA AquaPyr Model 25 units were chosen in a duty/assist configuration, and working at a hydraulic loading rate of 12 LPM/ m2 average daily flow which was 2 x peak and a solids loading rate of 0.05 kg/m2 daily average.

The resulting effluent quality after the filters was a Total P of <0.25 mg/l, BOD of 5 mg/l and TSS of <5 mg/l. The graph below shows the results of a 12 month period.

[caption id="attachment_15481" align="alignnone" width="1200"] Silver Lake WwTP: Effluent TP before/after the installation of the ACWA AquaPyr Ultra Low Waste Filter - Courtesy of ACWA Services[/caption] Summary

The ACWA AquaPyr Ultra Low Waste Filter has proven itself to be a robust cost effective solution in industrial and municipal waste water solutions. The total cost effectiveness of the AquaPyr filter, when compared with traditional cloth filters, further increases when looked at from a project cost basis due to the reduced civils works generally required for the installation and overall scheme requirements for the AquaPyr filter.

The ACWA AquaPyr Ultra Low Waste Filter is an innovative technology providing a solution for small and low flow water treatment works, where filter waste management and the hydraulic capacity of the existing works might make the use of a traditional tertiary solids removal process inappropriate or cost prohibitive due to the civils works and costs associated with their installation.

Water companies are facing ever tightening standards, including the treatment of micro-pollutants to almost non-detectable levels in drinking water, very low levels of phosphorus discharge from wastewater treatment, and the requirement to drastically reducing storm overflow spills. The proprietary silicon carbide (SiC) membrane and module is an innovative technology that provides some unique advantages for potable water, wastewater and CSO applications, and helps water companies increase their treatment capacities, reduce costs and reduce their carbon footprint; major drivers for the industry when selecting key process technologies. Silicon carbide (SiC) ceramic membranes

Silicon carbide ceramic membranes are submerged ultrafiltration flat-plate membranes with a pore size of 0.1 microns. They act as a physical barrier that blocks solids and pathogens, allowing clean water to pass through. The filtration process involves applying a slight vacuum to the membrane surface, pulling water through the membrane while contaminants are retained. After diamond, silicon carbide is the hardest material known to man.

One of the key advantages of SiC membranes, compared to any other organic or alumina ceramic membrane, is their natural hydrophilicity, which attracts water while repelling organic foulants. This reduces membrane fouling, improving filtration efficiency and reducing cleaning requirement. The system uses periodic back pulse washing and air scouring to dislodge accumulated solids, ensuring extended filtration cycle between chemical in place cleaning.

The SiC membranes are also chemically inert, sustaining pH between 2 to 13 and can act as a strong oxidising compound, such as ozone. They are also mechanically robust making them resistant to harsh mechanical and chemical cleanings.

[caption id="attachment_18309" align="alignnone" width="1200"] Cembrane SiC membranes, modules, stacks & towers - Courtesy of Enpure Ltd[/caption]

Key benefits brought by the adoption of the Silicon carbide ceramic membranes are:

Increased flow: Get up to five times more flow out of existing rapid gravity filters (RGFs) by using Silicon carbide ceramic membranes. Low carbon footprint: SiC can be installed in existing tanks available on site, reducing the need to build new concrete structures. Consistent water quality: The SiC membranes consistently produce water that meets and exceeds regulatory standards independent of feed water quality. Durability & reliability: After multiple years of operation, the SiC membranes show no signs of degradation and no decline of the membrane permeability, vastly improving whole-life cost. Operational efficiency: Low maintenance and remote monitoring capabilities minimise operational costs and staffing requirements. 25-year whole-life cost: The whole life cost is estimated to be significantly improved compared to the traditional alternative. [caption id="attachment_18308" align="alignnone" width="1200"] Applications of Cembrane SiC membranes - Courtesy of Enpure Ltd[/caption] Cembrane

Cembrane SiC membranes have been installed in over 250 facilities worldwide. The innovative technology provides several advantages against more commonly used organic and inorganic membranes including market-leading flux rates, longevity, robustness and ease of operation. The membranes are manufactured in Denmark and the USA, and have been utilised in more than 70 countries to providing safe drinking water and wastewater treatment.

Case Study: Gothenburg Water Treatment Plant (Sweden)

The Gothenburg Municipal WTP faced challenges reducing manganese levels to comply with regulatory limit of 0.05 mg/l. The plant used a conventional treatment process for treating borehole water by dosing potassium permanganate (KMnO4) to precipitate iron and manganese, followed by sand filtration. While this method effectively removed iron, it struggled to consistently reduce manganese to the required level resulting in non-compliant water.

Additionally, the plant needed to increase its capacity by 50% from 3,500m³/day to 5,200m³/day to meet growing demand. This had to be achieved within the existing filter footprint of 15m2, due to land ownership issues. An upgrade of the existing traditional green sand filters with KMnO4 dosing would have required 42m2 to achieve these requirements, whilst the SiC membrane alternative only required 15m2 and was therefore selected for pilot trials.

[caption id="attachment_18311" align="alignnone" width="1200"] (left) Installation of Cembrane SiC stack, (top right) Cembrane SiC stack from above, and (bottom right) SiC membranes have sprinkler cleaning option - Courtesy of Enpure Ltd[/caption]

Performance confirmed by successful pilot trials: To assess the SiC membranes’ performance, the customer conducted a two-month pilot test between 2015 and 2016. The test evaluated the system’s ability to remove iron and manganese, as well as its durability and maintenance needs. The results were highly positive; manganese concentrations were consistently reduced to below 0.02 mg/l and turbidity was also reduced to less than 0.1 NTU (significantly below the target of 1 NTU). Following the successful pilot, the municipality decided to fully implement the SiC membrane system.

Eighty SiC membrane modules were installed in two filtration tanks, enabling the plant to treat up to 5,200m3/day within the 15m2 footprint. The membranes are installed within modules, each containing 42 flat sheet membranes, providing a total membrane surface area of 6.85m2 per module. These membrane modules are stacked in towers, with up to 15 modules per tower. Each tower includes a top permeate module, which collects the filtered water, and a bottom diffuser module, which distributes air for cleaning purposes. For Gothenburg, eight towers comprising ten filtration modules were installed in two of the existing filter structures.

Conclusions: Three years after installation, the SiC membrane system has continued to perform exceptionally well. A full inspection revealed no signs of decline in membrane permeability or structural damage, and the plant consistently delivers high-quality drinking water with the following parameters being achieved:

Flows: 50% increase from 3,500m³/day to 5,200m³/day. Manganese: <0.02 mg/l (target <0.05 mg/l). Iron: Non-detectable (target <0.05 mg/l). Turbidity: <0.1 NTU (target <1 NTU). Recovery rate improvement: from 80% to 99%.

Conclusion

Cembrane SiC membranes give water companies the opportunity to expand and improve their treatment facilities at low additional cost and carbon footprint. Cembrane and Enpure are both part of SKion Water, who have a diverse portfolio of innovative companies providing technologies for water and wastewater treatment to municipal and industrial sectors. Enpure Ltd will deliver Cembrane SiC membranes throughout the UK.

During AMP7 over 800 sites were required to meet tighter phosphorus permits under the National P Removal Programme. The majority of these sites adopted the solution of using tertiary solids removal (TSR) plant with ferric or aluminium dosing to meet the permit requirements. There are 6 major TSR plant suppliers in the UK, three of which use the same technology, each with its unique feature, competing in the P removal market. This has driven the TSR technologies to evolve and improve, addressing the needs to enhance reliability and to minimise the use of chemicals whilst meeting increasingly stringent standards. FilterClear for phosphorus removal

FilterClear is a true depth filtration technology, with 900 mm of filtration bed depth. The influent is pumped to the top of the filter and flows through four layers of media: anthracite, silica, alumina and magnetite, which have decreasing particle size and increasing density. This configuration provides an equivalent of 4-stage filtration in a single vessel, allowing the filter to operate at a much higher filtration rate (up to 35m3/h) and achieve a better effluent quality than conventional sand filters; coupled with its much smaller footprint. FilterClear is a powerful tool in a designer’s armoury.

The key benefit of depth filtration is to enable the solids to be removed progressively through the entire depth of the 4-layer filter bed, extending the run-time and reducing backwash frequencies. The backwash can be controlled by timer or pressure. After backwash, the media will settle back to the original layers thanks to the carefully selected density and particle sizes of the four media types.

FilterClear has an average operating pressure of 0.4 bar, offering a low energy demand and a low operational carbon footprint.

Experience across the many FilterClear plants installed to date has highlighted the low cost of ownership, particularly with respect to operation and maintenance. The plants are fully automated and typically require just one annual service (less on sites with activated sludge upstream). There is no routine requirement for replacement parts or filtration cloths and the FilterClear plants require only a top-up of anthracite every few years.

Furthermore, all media layers are naturally-occurring minerals, thereby not introducing any microplastics or fibres into the treated effluent or dirty backwash water.

[caption id="attachment_13686" align="alignnone" width="1200"] FilterClear plant at Yeovil WRC - Courtesy of Bluewater Bio[/caption]

For chemical P removal, good coagulation and flocculation are critical. Many TSR technologies need purpose-built coagulation and flocculation tanks with mechanical mixing, and some will also require polymer dosing.

By comparison, FilterClear only requires coagulant dosing for P removal; no polymer or ballast material is required. This is because large flocs are not essential for depth filtration. Chemical dosing can be added directly upstream of the FilterClear plant via an inline static mixer, and flocculation will occur in the headspace inside the filter vessel, above the media bed, removing the need for mechanical mixing or a flocculation tank, thereby simplifying the asset and reducing associated costs.

The absence of a separate flocculation tank further minimises the FilterClear footprint, makes the solution simpler to build and operate and eliminates the associated operational and maintenance tasks. It also eliminates the need for an overflow from the flocculation tank which, having been dosed with coagulant, represents a compliance risk.

Design for manufacture and assembly (DfMA)

Increasingly, clients and their tier one partners are looking to minimise site construction activities and durations. FilterClear plants are designed to allow off-site assembly and testing, then delivery to site as a package plant. Where possible, the complete filter gallery, including backwash pumps, blowers, actuated valves, instruments and controls are skid-mounted and transported fully assembled. Site activities are then limited to coupling the filter vessels, adding the media and commissioning. This DfMA approach ensures both quality and safety are well controlled and ultimately delivers a better solution in a shorter time at a lower overall cost.

Health and safety is an integral part of the design process, ensuring that all equipment is safe to install, operate and maintain. Filtration and backwash of the FilterClear plant is fully automated, with minimum operational input. The filters are enclosed, with no moving parts or serviceable components within the vessels and need minimal operator intervention. Due to the enclosed, fully automated design, risk of operator exposure to wastewater or chemicals is minimised. Furthermore, all machinery is at ground level for easy access.

Proven performance

Most TSR plant suppliers prefer to offer an effluent total suspended solids (TSS) guarantee as a surrogate to a TP guarantee. However, water companies have realised that, at low concentrations, there is a very poor correlation between the TSS and TP concentrations thereby introducing compliance risk.

As the developer and owner of the technology, Bluewater Bio Ltd has a deep understanding of both the process and phosphorus removal, and accordingly are able to provide a TP guarantee. This offers the client and their contractor the simplest and clearest assurance of meeting the final effluent permit as well as being contractually most straightforward. FilterClear performance has been tested and proven at over 50 sites across most UK water companies, all reliably achieving the respective permit requirements for both TP and iron. Knowing that more stringent TP permits will be imposed in AMP8, Wessex Water carried out long-term trials to push the performance limits at several sites with impressive results.

[caption id="attachment_13681" align="alignnone" width="1200"] ‘Site A’ performance graph: Blue line shows the Total P concentration of the TSR feed and the green line shows the Total P concentration of the final effluent after FilterClear treatment - Courtesy of Bluewater Bio[/caption]

‘Site A’ is a typical small trickling filter site. In AMP7, a FilterClear plant was installed to meet a new 0.5 mg/l TP permit. The trial demonstrated that the plant achieved an average TP below 0.07 mg/l, with a 95%ile iron concentration of 0.27 mg/l. This performance has been achieved with an overall ferric dose of just 15 mg/l (including 1st point and 2nd point dosing) with simple flow-proportional dosing control, and despite some unrelated control issues during the trial. The long-term trials have demonstrated that FilterClear plants can reliably achieve a TP permit of 0.1 mg/l, making the solution future-proof. This offers the client a means of reducing WLC whilst adding future certainty.

FilterClear: Key advantages Proprietary stratified FilterClear media of up to four layers, specially developed and applied over 10 years for exceptional performance. High loading rate (25-50 m3/m2/h, i.e. 2-5x flow rate of competing technologies). High solids retention (low pressure drop and long backwash interval). High quality filtrate in a single step (SDI <3 : NTU <0.1 : BOD concentration <6mg/l). Low CAPEX (2-5x less media, fewer vessels). Low OPEX (no chemical use, low electricity consumption). Low backwash volume (<6% of filtrate, small backwash tanks, better yield, less waste). Small footprint (2-5x smaller filter area, smaller plant). Low O&M (simple, reliable, easy to maintain). Modular systems up to 1200m3/h per vessel. Case study: Wessex Water: Yeovil Pen Mill WRC

During AMP7, Wessex Water installed 14 FilterClear plants across its region for phosphorus removal, ranging from small sites less than 4,000 population to large sites over 75,000 population. Yeovil Pen Mill Wastewater Recycling Centre (WRC) is the largest site among these.

Yeovil WRC in Somerset is a large treatment works owned by Wessex Water, serving a population equivalent (PE) over 75,000 (including trade discharge). The existing treatment processes comprised:

Primary settlement tanks. High-rate plastic media filters. Intermediate humus tanks. Trickling filters (slag media). Humus tanks.

To meet tightened consent requirements, a major upgrade was required during AMP7; comprising tertiary MBBR plant and a tertiary solids removal (TSR) plant.

The TSR plant with chemical dosing is required to achieve the total phosphorus (TP) consent of 0.5 mg/l. On a whole life cost basis, taking into account process reliability, delivery programme, power demands, chemical consumption and maintenance requirements, FilterClear from Bluewater Bio Ltd was identified as the preferred solution, and the contract was awarded in May 2022.

The key elements of the FilterClear plant at Yeovil WRC are:

Number of filters (800mm diameter): 11 Number of backwash pumps: 2 duty/2 standby Number of backwash blowers: 2 duty/2 standby Number of clean backwash tanks: 1 Number of dirty backwash tanks: 1 [caption id="attachment_13685" align="alignnone" width="1200"] (left) FilterClear plant at Yeovil Pen Mill WRC next to a trickling filter and tertiary MBBR plant at Yeovil WRC and (right) Skid design at Yeovil Pen Mill WRC for easy access and maintenance - Courtesy of Bluewater Bio[/caption]

The FilterClear plant design has taken into account the following:

Treat the peak flow during filter backwashing. Ensure the solids holding capacity is adequate under the worst-case scenario. Manage the interfaces with tertiary pumping/ferric dosing. Minimise the whole life cost and footprint. Enable safe and easy access, lifting and maintenance (ALM).

Thanks to the high filtration rate, the FilterClear plant has a smaller footprint in comparison to conventional filters. The compact nature of the FilterClear plant makes it ideal for the very congested site at Yeovil. At the time of writing (July 2024), the FilterClear plant has been installed and is currently being commissioned.

Throughout the project, the design teams worked closely with Wessex Water on the ALM assessment to ensure that the plant is operator-friendly. Particular attention was paid to eliminating hazards during operation and maintenance.

Highest accolade - rising to the challenge in AMP8

Innovation plays a critical role in the water industry’s ability to adapt to climate change, population growth and new and emerging pollutants. Bluewater Bio Ltd continue to develop and enhance technologies so that they excel in performance, value, reliability and sustainability.

[caption id="attachment_13682" align="aligncenter" width="356"] FilterClear technology received a King’s Award for Enterprise (Innovation category) in 2024[/caption]

In 2024 Bluewater Bio Ltd received a King’s Award for Enterprise in the Innovation category for its FilterClear technology. The award was granted on a recommendation by the Prime Minister and approved by His Majesty The King and is the most prestigious award for a UK business. This award is further recognition that FilterClear has become the preferred choice for clients.

With AMP8 on the way, over 900 sites will be on the national P removal programme and FilterClear will play a major part in delivering a successful outcome.

Winchester House, 259-269 Old Marylebone Road, London NW1 5RA

| 020 7908 9500 | bluewaterbio.com |

During AMP8, increasing amounts of sludge will be generated as a result of new wastewater treatment processes that will be required in order to comply with the Water Industry National Environment Programme (WINEP) and to provide the necessary enhanced protection of the UK’s water courses. The additional sludge generated at small rural treatment works will add to the existing logistical and transportation challenges that water companies face, i.e. having to ensure that biosolids are moved in the most cost-effective manner between rural satellite treatment works and sludge dewatering hubs and sludge treatment centres. Containerised HUBER S-DISC

The Containerised HUBER S-DISC re-packages proven technology for small scale sludge thickening to provide water companies with a cost-effective solution that will help address their biosolids logistics challenge.

At the heart of the Containerised S-DISC is the HUBER Disc Thickener (S-DISC); it is well proven sludge thickening technology with more than 90 references in the UK and 1071 worldwide.

The S-DISC thickens flocculated sludge using a principle similar to that of a gravity belt thickener (GBT). However, whereas a GBT uses a continuous fabric filter belt driven between two rollers, the S-DISC uses an inclined rotary filter disc with a filter media of woven stainless steel mesh. Sludge ploughs are used to assist the drainage of filtrate and a scraper blade is used to remove sludge from the disc surface, very similar to their use on a GBT. However, the stainless steel mesh is much more robust than the GBT’s fabric belt and overall the machine is very compact and easily accessible for maintenance.

The S-DISC can thicken up to 38m3/hr (Size 2) of secondary sludge to >6% dry solids content with solids capture of >97%.

[caption id="attachment_22032" align="alignnone" width="1200"] Render of the containerised HUBER S-DISC sludge thickener - Courtesy of Huber Technology[/caption] Design for Manufacture and Assembly (DfMA)

The design of the Containerised HUBER S-DISC adopted a Design for Manufacture and Assembly (DfMA) approach with the focus on:

Reduced project lead time. Reduced production costs. Reduced site assembly time and associated H&S risk. Standardisation around a plant layout optimised for operation & maintenance. Full compliance with Water Industry M&E Specifications (WIMES).

The S-DISC and ancillary equipment are mounted on a galvanised steel skid which has integral cable ducts for effective cable management and for reducing potential trip hazards associated with surface mounted cable management. The skid also includes an integral sump under the poly dosing equipment to act as a bund to capture any spillages. Level control in the bund indicates if there is liquid spilling into the bund and shuts the plant down to prevent further spillage of polymer. The bund has enough space to locate a day tank of concentrated liquid poly or polymer can be fed from an external IBC with a level control interface and IBC heating jacket power supply being provided from the container.

[caption id="attachment_22029" align="alignnone" width="1200"] Render of the Containerised Huber S-DISC sludge thickener - Courtesy of Huber Technology[/caption]

The skid is incorporated into a purpose built shipping container with bi-fold doors along one side and double doors at each end in order to provide unrestricted maintenance access to the plant. The plant can also be supplied as a skid mounted assembly where there is already an existing building to re-use.

An operation and maintenance risk assessment was undertaken during the design phase and then validated on the first production unit. The design brief was to ensure that this packaged solution eliminated any compromises in relation to maintenance activities.

Clear customer advantages

An integrated packaged solution which includes:

Sludge feed and discharge pumps. A bunded polymer preparation unit and dosing pump. Heating, lighting and ventilation. A WIMES 3.04 compliant control system. A reduction in the number of both supplier interfaces and control interfaces that would otherwise be needed for a third party control system. This dramatically reduces project lead times and helps to de-risk the customer’s project. Case study: Welsh Water - St Davids STW

Welsh Water required a sludge thickener to reduce the number of tanker movements from this site. This was motivated not simply by the need for more efficient sludge transportation but also due to the narrow access in and out of the area and a recent local hotel development. The treatment works has a population equivalent of 2,300 which increases threefold in the summer due to tourism.

[caption id="attachment_22031" align="alignnone" width="1200"] Containerised HUBER S-DISC sludge thickener at St Davids STW - Courtesy of Huber Technology[/caption]

The sludge thickening plan was required to thicken 16m3/hr of surplus activated sludge from 0.5% dry solids content to >5%. Having recently successfully installed an S-DISC thickener at Fishguard STW, it was deemed to be appropriate technology to use at St Davids STW. However, there was a need at St Davids to provide a building or enclosure for the sludge thickening plant as none existed on this isolated site.

A Containerised HUBER S-DISC size 1 was identified as the ideal solution. The container was based on a 20’ high cube ISO shipping container which included heating, lighting and ventilation. By offering a package solution, the need for on-site construction and M&E installation was minimised. All assembly work was undertaken at Huber’s Chippenham works and the completely assembly was fully tested prior to dispatch. The control system was design and manufactured in-house by Huber ensuring compliance with Welsh Water’s electrical specifications including the use of Mitsubishi PLC automation.

The unit was delivered in late 2022 and installed on a pre-prepared plinth. It was then commissioned in March 2023. The S-DISC thickened sludge to 5.5% dry solid content with a polymer consumption of <2 kg/tds. Filtrate quality was <200 mg/l SS demonstrating a 98% solids capture rate.

The success of this project has subsequently led to ten more units being delivered to Anglian Water, Scottish Water, Severn Trent and Thames Water.

Suspended solids carried in water can cause a range of harmful effects in rivers, lakes and oceans, making the capture and removal of these solids critical for effective environmental protection. To address this problem, the project focused on optimising the stacked trays that remove high levels of suspended solids from wastewater. Combining optimisation methods and computational fluid dynamics (CFD), the project was able to derive new designs for hydrodynamic solids removal components that would have been difficult or impossible to achieve using traditional engineering methods. The research was part of a Knowledge Transfer Partnership (KTP), supported by the UK government’s innovation body Innovate UK, which began in July 2019 and ran until September 2021. It builds on years of collaboration between Hydro International and the University of Exeter in the field of CFD. The core of the project involved the optimisation of stacked trays that enable the removal of high levels of suspended solids in wastewater, with the primary objectives being to improve performance and reduce maintenance requirements. This was a complex, multi-objective, high-dimensional problem, so the team needed to adopt an unconventional approach in order to solve it. To tackle the problem the project team coupled Bayesian optimisation techniques and CFD modelling, using a Bayesian optimisation toolset originally developed by the world-renowned Machine Learning Group at the University of Exeter. Bayesian optimisation was selected as it can be an order of magnitude more efficient than alternative approaches, such as genetic algorithms, on such complex design problems. The Bayesian optimisation toolset was then connected to CFD simulations, allowing the team to use computing power to automate the design and evaluation process. The team ran the CFD simulations using supercomputers in Exeter and Bristol, with each optimisation run modelling some 300 designs at a time. This would have been impossible to achieve using other optimisation techniques. The team was one of the first in the world to use these techniques on new GW4 Isambard super-computing architectures. The team subsequently corroborated simulation results through physical testing of prototypes in Hydro International’s hydraulics laboratory in Clevedon. The outcome of the project was a new stacked tray design that improves grit removal performance and enables the production of more compact systems that can handle higher wastewater flows and requires less maintenance—an excellent example of combining academic research with commercial incentives to address real-world challenges. Although the project was focused on improving technologies that will be applied to future iterations of the HeadCell® advanced grit removal system, the findings are fundamental to Hydro International’s core technologies, and will be applicable to other products that rely on the same hydrodynamic principles such as Downstream Defender® and First Defense®. In addition, not only did the project apply methods for complex design optimisation already developed by the University of Exeter, but it also drove new developments in multi-objective optimisation and constraint handling, resulting in new advances in expertise and understanding. Following completion of the project, Innovate UK assessed the KTP and awarded it a Grade A, or “Outstanding”. Dan Jarman, Hydro International’s Group Technical Manager said:

“We have a long history of investing in new science and new technologies to help our customers, and this project continues that tradition. This is the first time that Bayesian optimisation and CFD techniques have been applied in the water sector, which represents a significant step forward in product design excellence. In a sector that has been unfairly criticised for being slow to adopt new technologies and techniques, we’ve shown that there are teams out there willing to push boundaries in order to benefit utilities, consumers and the environment.”

Jonathan Fieldsend, Professor in Computational Intelligence at the University of Exeter said:

“This project is an excellent example of what can be achieved when a KTP involves such a wide range of talent and experience. To achieve its outcome, it has needed academics from the Computer Science and Engineering departments, specialists from industry, and support from a highly-skilled impact and business team. It has delivered significant enhancements for an important Hydro International product - in the crucial area of wastewater management - and has also led to advances in applied optimisation techniques and algorithms which have use more broadly in CFD-driven design.”

About Hydro International Hydro International is a global company that provides advanced products, services and expertise to help municipal, industrial and construction customers to improve their water management processes, increase operational performance and reduce environmental impact. With over 40 years of experience and a reputation for engineering excellence, businesses and public organisations all over the world rely on Hydro International products and services to reduce flood risk, improve water treatment and protect the environment from water pollution. Headquartered in Clevedon, UK, Hydro International has a network of over 80 distribution partners and serves customers in more than 40 countries. About the University of Exeter The University of Exeter combines world-class research with excellent student satisfaction, ranking in the Top 150 of the THE and QS World University Rankings. We are one of the very few universities to be both a member of the Russell Group and have a Gold award from the Teaching Excellence Framework (TEF), evidencing our international reputation for excellence in teaching and research. Each year, the University of Exeter delivers over 1500 projects with industry and generates over £52m from this work. We believe impact is about making a difference, and our world-class researchers have an excellent track record in making valuable contributions to our society, economy and the environment. Our dedicated KTP team - based at the University’s Innovation, Impact and Business directorate - is the leading Knowledge Base partner in South West England and has successfully delivered over 100 KTP projects to date, with 85% of these rated good to outstanding.     To learn more about how our inlet works specialists can help you with your wastewater needs M&N Electrical & mechanical Services Ltd | +44 (0)1305 821142 | www.hydro-int.com/ukwws    

Carbarns Wastewater Treatment Works (WwTW) is located in Wishaw, to the South-East of Glasgow, within the Clyde River valley. The site is part of the ‘Clyde 7’ group of Scottish Water treatment facilities, serving a population of over 54,000 from Wishaw and Overtown areas. Along with the inlet works, the site has primary and secondary treatment and phosphorous removal. Treated water from the plant is discharged into the River Clyde. The 6mm fine inlet screens at Carbarns WwTW were failing regularly as the screen panels were plastic and very prone to breaking, particularly following storm events when flows were higher than usual and contained more debris. Scottish Water was having to stock spare panels on site and replace them as often as every week, depending on the weather. When the inlet screens failed, a considerable amount of rag was feeding through to the primary settlement tanks, causing chokes in the sludge pumps. When the screens tripped out in storm conditions the bypass screen would blind up in minutes, not allowing enough time for standby operators to reach the site, and causing flooding at a nearby property. The result was a significant amount of time and resources spent on clearing these chokes and blockages and cleaning up by the operations team. The biggest impact of this inlet issue was the financial and carbon implications. Carbarns WwTW would normally send sewage sludge directly to the Daldowie fuel plant, near Glasgow, which processes it into a renewable, low carbon form of biomass fuel pellet. However, because of the high content of rag in the sludge caused by the inlet screen failures, it could not be sent directly to Daldowie Fuel Plant but had to be taken for further processing to Shieldhall WwTW, some 20 miles away on the other side of Glasgow. This involved up to 23 tankers a week transporting the sludge to Shieldhall for additional treatment, before it could be pumped over to Daldowie. The associated costs of transporting the sludge to Shieldhall WwTW were considerable. [caption id="" align="alignnone" width="1200"] Carbarns WwTW inlet works screens[/caption] Scottish Water worked with Hydro International’s UK Wastewater Services team, M&N, to evaluate the site and propose a solution. The team installed a Kuhn KHU-S Multirake Boomerang 70mm coarse screen to provide protection to the FSM escalator screens by removing the larger coarse screenings. Two FSM FRS 111 escalator screens were then fitted at 60°, providing an impressive maximum flow capacity of 770 l/s each, to provide fine screening of the sewage inflow. The screens are running in a duty standby mode, conducted automatically by the control panels which were supplied for all equipment. Each of the screens has capacity to take the full flow to treatment, should one need to be taken off-line for service, maintenance, or repair.  The strong screen panels are stainless steel so able to withstand storm flows, combatting the initial issue of weak plastic-based material screens. A launder system was installed to transport rag to two Kuhn KWP-HD 400/1200 wash presses to process, wash and compact the rags. Once the new inlet works package was installed, the primary settlement tanks and aeration tanks were cleaned to ensure that no rag was left in the system.  This was an additional cost of £106K before Daldowrie Fuel Plant could accept the sludge again. Simon Light, National Sales Manager for Hydro International, said:

“We needed to find a high-quality effective solution for the Carbarns WwTW to prevent any further overflows, and to help reduce the high cost and carbon impact the high content of rag in the sludge was creating. Our specialist inlet works team designed and installed a robust, reliable inlet works system that combines screening, washing, transport, compaction and dewatering in a single cost-effective and sustainable standalone solution.”

Stephen Heatley, WW Operations Team Leader at Scottish Water, comments:

“Knowing the team for over 20 years, we were confident that they would provide a solution that works exceptionally to meet our needs. Since the project’s completion in September 2020, there has been a significant reduction in costs and carbon use now that the sludge can be transported directly to Daldowie Fuel Plant for processing. The amount of reactive time that operation staff previously needed to spend dealing with chokes and cleaning up has dramatically reduced, with a knock-on effect that morale has improved, providing more time to spend on proactive tasks.”

Moving forward, the UK Wastewater Services team will service the screens every year and provide maintenance to ensure the equipment is operating at optimum performance.     To learn more about how our inlet works specialists can help you with your wastewater needs M&N Electrical & mechanical Services Ltd | +44 (0)1305 821142 | www.hydro-int.com/ukwws    

Project Information Location: Swansea End client: Welsh Water Main contractor: Morgan Sindall Scope of works: Design, manufacture, delivery and installation of the PFET and Blending Chamber structures for Gowerton WwTW Background The reasoning behind the works at Gowerton was a requirement to meet permit conditions in South Wales by 2020. It is a cost-effective approach to challenging flow management at Water Treatment works which enables DCWW to meet their spill permit regulations as laid down by the Welsh Government and Natural Resources Wales. The client was working to an extremely tight programme to achieve consent dates, which meant that the FLI Precast Solutions precast construction methods delivered key advantages over the traditional build process. On completion of the design the precast panels were produced off site at the same time as the 500,000m3 excavation was undertaken to receive the panels. The area was suitably prepared for the delivery of the panels which was coordinated with the site team and the client’s operators to facilitate the existing treatment process. Key drivers for the scheme included the requirement for complex M&E integration which also lends itself to the FLI Precast Solutions design and production philosophy for off-site manufacture. [caption id="" align="alignnone" width="768"] Precast concrete structures under construction - Courtesy of FLI Precast Solutions[/caption] The Gowerton scheme is the first project in the UK to utilise American company WesTech’s Flexfilter technology. Solution Controlled production of elements to a very high standard. Integration of complex M&E systems. Reduced H&S risk on site. Programme savings in the works through a shorter construction programme. Reduced workforce on site resulting in reduced main contractor preliminaries. Reduced construction traffic for the local area, meaning less disruption for residents. Lower carbon footprint as a result of the FLI Precast Solutions construction methodology, which is typically half that of traditional in situ build. Flexibility for programme phasing on site, if necessaryAll units manufactured off-site and called in as dictated by the programme. FLI Precast Solutions provide a secondary sealing system which traditional methods do not offer. Clear works development through Building Information Modelling (BIM) and cutting-edge design capability. [caption id="" align="alignnone" width="768"] Precast concrete structures under construction - Courtesy of FLI Precast Solutions[/caption] A word from our client: Kevin James, Project Manager - Wastewater Infrastructure, Welsh Water Capital Delivery Alliance:

“The scheme involved installing various complex precast structures to house a new flexseal treatment system that will deal with foul water storm flows before discharging to the consented outfall, the first of its kind in Europe. The PFET structure alone was 27m x 26m x 8m deep (at the deepest part), consisting of 3 different levels and various interconnecting chambers.

Due to the high priority of the scheme and the tight deadlines to meet NRW consents, a precast option was progressed. This enabled the design of the structure to be passed to FLI Precast which released our design team to concentrate on other areas of the scheme, showing significant programme savings on the design.

Due to the competency and efficiency of the FLI Precast team the precast installation was completed on time with zero accidents/incidents and to the end client’s satisfaction.”

  For more information: FLI Precast Solutions: +44 (0)1279 423303 | www.fliprecast.com    

Thames Water’s Greenham Common Sewage Treatment Works (STW) is situated in the shadow of a former US Air Force base in Bishops Green, Newbury, and alongside the River Enborne. The untreated wastewater that Greenham Common receives has a high rag content and repeated screening carry over was affecting the full treatment process, the overall performance of the site and risked that the site would go out of environmental compliance. Thames Water approached Hydro International’s UK Wastewater Services team, M&N, to evaluate the site and propose a robust solution. The team installed the MNSS Combined Screen, to capture larger influent materials at the front end of the wastewater treatment process, protecting and improving the efficiency of the downstream treatment system. Due to the site hydraulics/flows, there was no reliable wash water system for the MNSS Combined Screen, so the team found an innovative way to solve this. They created a bespoke system, including pumps, to use the effluent from the site’s primary settlement tank. The spray nozzles on the MNSS Combined Screen were also altered to accommodate the change. [caption id="" align="alignnone" width="1200"] Greenham Common STW MNSS Combined Screen[/caption] Simon Brum, Project Manager, Hydro International’s UK Wastewater Services Team, said:

"We needed to find a quick and effective solution for the Greenham Common STW to prevent any overflows, and designed and installed a robust, reliable inlet works system that combines screening, washing, transport, compaction and dewatering in a single cost-effective standalone solution.”

Henry Crompton, Lead Project Engineer at Thames Water Utilities Ltd, commented:

“We needed a suitable solution that was effective and within budget, and the team delivered that. We are very happy with the work undertaken on this site and will be using it as an example to our other Thames Water teams who may encounter the same issues.”

Handling flows of up to 150 l/s, the MNSS Combined Screen is designed for smaller plants and those facilities that require a more cost-effective screening solution - helping engineers, operators, and site owners to maintain treatment effectiveness even at remote and budget - constrained sites. [caption id="" align="alignnone" width="1200"] Greenham Common STW MNSS Combined Screen[/caption] Optimised for reduced maintenance and extended component lifetimes by the UK Wastewater Services team, only the MNSS Combined Screen achieves a screenings capture ratio of 53%, the highest of any independently tested 6mm combined screen.     To learn more about how our inlet works specialists can help you with your wastewater needs M&N Electrical & Mechanical Services Ltd | +44 (0)1305 821142 | www.hydro-int.com/ukwws    

At Pellows Waste Disposal Services, near Truro, a typical 4.5m3 tanker (1,000 gallons) that used to take over 20 minutes to empty, can now get back out on the road to collect more liquid waste after less than three minutes discharge time. The turnaround is due to "The Beast" made by SAVECO Environmental, that with a fully integrated 5mm screen, conveyor and compactor, all in one unit, removes harmful debris and dewaters it prior to discharge. It can handle 200m3/h and up to 6-8% solids as a plug-and-play system. Payback is expected in just four months, as Pellows’ Director, James Martin, explains:

“The Beast has far exceeded our expectations. It injects water to accelerate the process, and is so much more efficient and robust than our previous system. Investing in The Beast is part of a major upgrade that we’ve put into place to address the big changes that have happened in Cornwall’s collection and disposal of liquid waste.”

The upgrade at Pellows, which includes a centrifuge, aeration, and larger tanks, has enabled the company (established in 1964) to expand its customer-base by offering a complete in- house service. It will also provide a potential lifeline to other contractors who collect liquid waste from the holiday parks, factories, hotels and many thousands of homeowners in Cornwall that are not connected to the sewer network. The closure in April 2022 of what turned out to be two large disposal sites that were trading illegally, has forced contractors into sending their vehicles long distances away to discharge their collected waste. The headache has been partly alleviated by being able to take some liquids to be treated by South West Water, but during heavy rainfall and storm events, the water company has had to keep its gates closed because capacity has been reached. James Martin continued:

“Storms and flooding from prolonged rainfall is all too common these days. We couldn’t just stop working for long periods due to the weather, letting our customers down, or keep sending our vehicles miles and miles away to unload. We had to act to protect and grow our business, so first contacted Centri Force, who make very good decanter centrifuges. They gave us plenty of good advice about how we could become independent by treating the collected waste ourselves, which included a strong recommendation of "The Beast" from SAVECO Environmental.”

The pneumatic press (with de-stoner) that had been in operation at Pellows not only took far longer to receive incoming waste, but, according to Richard Montanaro, Managing Director of Centri Force, was too small and far less sturdy, with too many areas where the process would require costly maintenance or be likely to slow or fail.

“In comparison, "The Beast" is very well designed. It is a great product that integrates very well with other parts of a plant to provide an excellent front-end pre-screen. With a centrifuge as part of a process, it gives us exactly what we’re looking for, and has helped Pellows greatly increase productivity and take this important step to becoming a liquid waste contractor with its own treatment facility".

Environmental wet waste is a big issue, and Cornwall, with far less infrastructure and sewer connections than many counties, faces some big challenges, so it is good to see Pellows play a big part in reducing the environmental impact of septic tank liquids.” Rotating around its axis, The Beast’s cylindrical filter conveys screenings into a loading hopper placed in the centre, whilst a set of spray nozzles washes the filter during operation. A screw, placed inside the conveying pipe (with its top inside the discharge hopper), conveys the screenings towards the treatment stages, during which organic substances are washed out. Subsequently, solids are compacted and dewatered in the compacting and drainage area, before exiting through a discharge chute. Despite septic tank contents often containing solidified calcium, rocks, stones, and sanitary products, installation of The Beast now sees Pellows’ 27-tonne artics discharge waste in less than 13 minutes, compared preciously (depending on the thickness of the liquid) to 45-minutes, up to one hour. Craig Webb, SAVECO’s Municipal Sales Engineer, commented:

“We have worked closely with Pellows and Centri Force to bring about a big improvement in treating liquid waste. Allowing effluent to be put directly through "The Beast", which avoids placing further stress on an existing plant, is also a huge benefit to water companies. Liquid waste contractors and the water industry can see that by screening, washing, conveying and dewatering - all in one unit - there is a reduction in risk, and the opportunity to make big savings by removing the need for multiple pieces of equipment.”

James Martin from Pellows, continued:

“The whole system is so much better now. We get better biosolids too at the end of the process. Apart from South West Water, we’ve now become the first company in the County who have the capability to treat liquid waste for safe disposal into the foul sewer main.”

  For more information contact SAVECO Environmental Ltd | +44 (0)1684 299104 | https://saveco-water.co.uk