Supply Chain - Health & Safety - Risk Assessments

To ensure compliance with tighter Environment Agency permits for phosphorus removal, the number of phosphorus reduction schemes have quadrupled since AMP5 and is seen by some as one of the biggest challenges ever to face the water industry. The Water Industry National Environment Programme (WINEP) is a programme of actions that water companies are required to undertake to improve the environment and to meet the environmental legislative requirements that apply to water companies in England. Southern Water are undertaking a five-year programme of work, with CMDP JV appointed as framework contractor in 2020 for the east region covering Kent, East and West Sussex and Surrey, along with emergent works in the West, with responsibility for delivering 37 WINEP projects during AMP7. Design In collaboration with the design team, a variety of solutions have been delivered, from a small bespoke 1m3 ferric dosing solution at Cherry Gardens WwTW, to larger scale projects such as a 40m3 caustic dosing system along with a 7-lane deep bed sand filter at Scaynes Hill Treatment Works. Process engineering specialists from CMDP JV (a joint venture between Costain and MWH Treatment) collaborated with Southern Water to review the scope of each site, identifying opportunities for no-build and low-build solutions by optimising existing assets to meet permits. This was achieved by commissioning extended load and flow surveys to pinpoint issues and identify the level of intervention required. [caption id="" align="alignnone" width="1200"] Excavation for sub-slab level ducting and drainage pipework to the chemical dosing kiosks - Courtesy of CMDP JV[/caption] This approach identified full no-build solutions at four sites, allowing £8m to be invested in other sites which presented greater risk. CMDP JV also invested in trials at three sites, which helped to establish that the existing tertiary treatment facilities were capable of satisfying the requirement of the new permits, thus providing millions of pounds of savings to Southern Water. At the start of AMP7, it was decided to undertake the design work in a shared integrated space with Southern Water, CMDP JV, subcontractors and supply chain working closely together to ensure a well thought out, robust design was in place before starting on site. The main objective of this approach was to ensure the on-site delivery and commissioning of the projects runs smoothly and is ‘right first time’. The team engages with Southern Water in weekly workshops to review design; challenging specifications and value engineering solutions by walking through the design virtually to gain buy-in to the solution and first-time approval at Risk and Value (R&V) meetings. The team approach ensures design consistency and use of standard solutions through a core design team of civils, mechanical, electrical and process designers. Southern Water WINEP: Supply chain - key participants Client: Southern Water Delivery partner: CMDP JV Costain MWH Treatment Civils installation: Coleman Construction & Utilities Ltd Electrical installation: Econotech Ltd Mechanical installation: Pipe Systems Ltd MEICA: Bridges Electrical Engineers Ltd MCC/switchgear: MCS Control Systems Ltd Tertiary treatment plant: Bluewater Bio Ltd Lamella plant: ATAC Solutions Ltd Phosphorus & iron monitoring/kiosks: Servitech International [caption id="" align="alignnone" width="1200"] (left) Lifting of tertiary treatment plant, control panel and pipework manifold and (right) loading of media into TTP pressure vessels - Courtesy of CMDP JV[/caption] Smart construction solutions The team has formed strategic relationships with the supply chain partners to retain learning and efficiencies across the WINEP sites. This is helping to support the client in a ‘left shift’ approach, bringing production thinking and constructability expertise into the design phase to enable safe, efficient construction. Supply chain partners attend constructability reviews with construction delivery leads and the design team to ensure right first-time installation. The use of visual tools such as BIM 360 and Synchro 4D optimise the sequence, resolve interfaces, and develop logistics plans. One example of this approach bringing programme, budget and environmental benefits, is the review of logistics and collaboration with the client ecologist at Wingham (Dambridge) WwTW. This identified opportunity to reuse spoil in redundant storm tanks to create a new habitat. This saved over 100 lorry journeys, £50,000 in cost and 3.62t CO2e. Safety focus Despite working across multiple active projects and tackling a range of challenges including deep excavations, complex deliveries and lifts plus a variety of temporary works, safety has remained the highest priority of all times. This led to the team achieving zero loss of time injuries across the programme during 2022, after 1,986 days worked across the programme. [caption id="" align="alignnone" width="1200"] Close-up of pre-fabricated off-site manifold block - Courtesy of CMDP JV[/caption] Ticehurst WwTW One example of where the team has successfully implemented a phosphorus reduction scheme is at Ticehurst WwTW, East Sussex, where the scope of work included: Chemical dosing Two dosing plants were incorporated into the treatment plant: ferric and alkalinity. The ferric dosing reduces phosphorus levels, while the alkalinity dosing balances the pH levels, which can be affected by the ferric dosing. As the ferric dosing acts as a coagulant, increasing the volume of sludge produced, a tertiary treatment plant was installed to filter the final effluent with increased solids, removing phosphorus from the wastewater. To ensure safety during chemical deliveries, an interceptor chamber was constructed. This will retain any chemicals spilled during the delivery process (eg. in the event of a tanker failure or hose split). Retaining the chemicals within the intercept chamber mitigates the risk of contamination to either the normal site drainage system, which feeds back to the inlet of the works, or the surrounding environment. Monitoring system To maintain compliance with regulations, a phosphorus and final effluent monitoring kiosk from Servitech International Ltd was installed. This monitoring system ensures that the effluent leaving the treatment plant meets the required standards. A pH monitor was added to verify the pH levels of the final effluent, guaranteeing its suitability for release. MCC A new MCC (motor control centre) was installed; serving as the central control hub and powering the site. Additionally, a new S2000 telemetry outstation was installed. This enables communication between new and existing plant, and Southern Water’s main control centre, enabling monitoring of any alarms on the site. Potable water supply To meet the requirements set by Southern Water, a potable water supply was essential for the treatment plant. [caption id="" align="alignnone" width="1200"] Directional drilling rig completing second drive - Courtesy of CMDP JV[/caption] While an existing final effluent water supply was available for plant maintenance activities, the installation of safety showers and eye-baths required access to clean, drinkable water. The nearest connection was 350m away off the site to the west. This required a pipeline to cross private fields and the neighbouring Dale Hill Golf Club. To reduce the impact on local stakeholders, a directional drilling technique was deployed.  This involved deploying a small drill head, which can drive up to 100m underground. This only required a small number of pits to be dug, rather than digging a trench across the whole length of the pipe. Site access An additional challenge arose due to the treatment plant’s sole access road, which crosses the golf course. To ensure the safety of drivers traveling along this access road for work or deliveries, close cooperation with golf course management was necessary. Timetable/progress CMDP JV commenced site mobilisation in August 2021. Civils works began in October, followed by early M&E installation works which enabled early start of ferric dosing and phosphate and ferric monitoring. The construction completion milestone was achieved in August 2022, with takeover and final completion due by the end of 2023, following a period of process optimisation. The project was completed with zero safety, health and environmental accidents or incidents. [caption id="" align="alignnone" width="1200"] Completed installation of tertiary treatment plant - Courtesy of CMDP JV[/caption] Looking forward CMDP JV will continue to support Southern Water’s WINEP projects, with 18 schemes planned over the next two years to complete Southern Water’s AMP 7 portfolio. This includes Lingfield WwTW in Surrey, which will include new tertiary treatment, biological trickling filter, installation of a new pumping station, two pumping station upgrades and a new caustic dosing system. At Tunbridge Wells South, work will include a new 22.5m diameter final settlement tank, new caustic dosing and refurbishment of the ferric dosing facilities. CMDP JV is playing a key role in Southern Water’s response to the challenges posed by WINEP, and will continue to implement learnings from previous works as the programme progresses.

According to the Environment Agency, over 450,000 monitored stormwater discharge events occurred in England last year. To address this issue, the government’s Discharge Reduction Plan aims to cut the number of spill events by increasing the stormwater volume allowance - the amount of stormwater that must be retained on-site before being released into nearby water bodies - at wastewater treatment works throughout the country. The project formed part of £27.8m storm overflow discharge programme to increase stormwater storage capacity across 41 wastewater treatment sites. Background

The programme of work ensures compliance with regulatory requirements and supports the industry’s commitment to reduce storm overflow discharges at wastewater treatment sites.

This storm tank project required the installation of a new 110m3 storage tank that will reduce stormwater discharges at a nearby nature reserve, protecting local water quality, supporting the area’s natural environment and increasing biodiversity in the surrounding lakes. Constructed in the Midlands, the storm tank was the final scheme in a programme of ten that Stonbury had delivered to increase stormwater storage capacity across the region.

[caption id="attachment_32448" align="alignnone" width="1200"] Existing site pre-construction - Courtesy of Stonbury[/caption] Site description

The site is surrounded by industrial and residential areas to the south and west, and woodland and arable land to the north and east. Immediately north of the wastewater treatment works lies the nature reserve. This comprises plantation woodland and three large open-water bodies, the largest of which contains an extensive reed bed. The reed bed is one of the largest in Derbyshire, and this habitat and its surrounding mudflats provide ideal conditions for wildlife and support more than 200 recorded bird species.

The new storm tank was constructed within the wastewater treatment works in an area of semi-improved grassland of limited ecological value. The wider site contains additional grassland, woodland, scrub and a small area of wet woodland habitat, all of which were considered during project planning and delivery.

Project scope

A summary of the works delivered is as follows:

A reinforced concrete storm tank of internal dimensions 13m x 4.6m x 2.42m average depth. 5 (No.) 1200mm diameter precast concrete chambers and a 450mm diameter storm overflow twin wall HDPE storm overflow diversion pipe 15m long. 400mm diameter ductile iron (DI) storm overflow inlet and outlet pipe to new storm tank. 400mm diameter HDPE/SS 316L penstock from Althon Ltd within the storm tank inlet chamber. 150mm diameter DI storm tank drain down pipe with a 2.5m deep, 1200mm diameter precast concrete chamber. 150mm diameter HDPE flap valve fitted inside Storm Tank No. 3 at the end of the new drain down pipe. Stainless steel weir box sized 600mm x 450mm x 450mm within the storm tank and a stainless steel weir wall 800mm x 650mm inside the inlet chamber. An ultrasonic transducer head with a control unit in the site control building with new overflow spill to the river telemetry alarm and associated cabling. Modifications to the PLC to create a spill to river alarm from the new storm tank (Storm Tank No. 4) and a new storm tank page on the HMI. [caption id="attachment_32443" align="alignnone" width="1200"] Demolition of the redundant humus tank - Courtesy of Stonbury[/caption] Habitat management

An ecological appraisal was undertaken during the pre-construction phase to determine the presence of protected species on, and immediately surrounding, the construction site. This included a site walkover and a desk top survey carried out by the ecologist to identify/consider if any of the following were present - fauna, amphibians, reptiles, birds, bats, badgers, and any other notable and legally controlled species.

Results revealed a small number of marsh orchids (Dactylorhiza sp.) were present within the grassland immediately south of the proposed new tank location. While risk was low, to mitigate damage, the report stated that if the area was to be disturbed, the orchids should be removed and translocated by an ecologist to the adjacent grassland outside of the footprint of works, after a thorough assessment of the receptor area by the ecologist.

Supply chain - key participants Principal designer & contractor: Stonbury Ltd Designer: Mason Clark Associates Ecological appraisal: Habitat Works Shuttering & shoring: MGF Ltd Concrete: Cemex MEICA installation: CEMA Ltd Penstocks: Althon Ltd [caption id="attachment_32440" align="alignnone" width="1200"] Concrete base of the new storm tank - Courtesy of Stonbury[/caption] Construction

An overflow diversion was installed and air tested in accordance with the client’s Engineering Specifications to allow works to begin. Once this was in place, the two redundant concrete humus tanks were demolished. Waste materials where crushed on site and reused as hard core for the new storm tank base to reduce waste and carbon emissions.

The diversion pipe and chambers were constructed first so that storm overflows could be re-routed around the proposed excavation, with the end connections installed during dry weather periods.

The location for the new tank (Storm Tank No. 3) was prepared by installing temporary works which allowed the excavation for the new tank to take place. Sheet piles and frames were driven into the ground using a 13t excavator equipped with a piling hammer, providing support for the existing grounds. The team then demolished the redundant tanks.

Completion of these two phases allowed Stonbury to begin the excavation works, increasing the ground depth to the correct level for the new tank. We then demolished demolition the redundant humus tank before installing the shuttering and steelwork to form the new concrete base and washout channel. When the concrete had cured, shuttering was removed and the steel reinforcement for the concrete walls was installed by sub-contract steel fixers, before installing the shuttering to form the new walls. Concrete was cast in situ using a concrete pump delivered to site by MGF Ltd with the correct bracings.

[caption id="attachment_32445" align="alignnone" width="1200"] Formwork for the tank walls - Courtesy of Stonbury[/caption]

Once the construction of the new concrete tank was competed, drainage was installed. First, the sump drain between the new storm tank (Storm Tank No. 3) and the existing Storm Tank No.1A were installed and flap valves were fitted in Storm Tank No.1A (during dry weather conditions), with tankers and pumps on standby to remove unforeseen storm flows.

Core drilling took place to allow for the new inlet pipework to be installed from the inlet chamber. The new pipework was cast in with concrete and a Hydrotite Waterbar around the pipe and cored hole. A second core hole was made to accommodate the overflow pipework from the new tank to the overflow outlet chamber. A drop test was carried out to identify any points of egress, which verified that the new tank was watertight.

The final stage was the MEICA installation, which was supported by CEMA Ltd who installed the ultrasonic level probe and spill-to-river alarm system.

The new storm tank was brought online by switching flows to enable the tank to receive incoming stormwater. An O&M manual was issued to operations (to be stored in the control building) and all operational staff were invited to attend a short training event on the new storm arrangement, held on-site.

[caption id="attachment_32439" align="alignnone" width="1200"] MEICA installation - Courtesy of Stonbury[/caption] The Carbon Reduction Curve

A key component in aligning Stonbury’s processes with the sector’s strategy to become carbon neutral is to identify the potential for carbon reduction in all projects. Guided by the Carbon Reduction Curve, Stonbury worked from the design stage to inform the design and explore lower-carbon solutions.

The Carbon Reduction Curve represents a carbon reduction hierarchy across the lifecycle of a project, from planning to operation. The curve shows the greatest opportunities to reduce carbon early in the process during the planning and design stages, where strategic decisions can avoid or minimise carbon-intensive outcomes. The hierarchy promotes a ‘build nothing’ to ‘build efficiently’ approach, where building nothing may be achieved through better asset maintenance, ‘building less’ is achieved through refurbishing existing assets, ‘build clever’ uses green alternatives if new asset creation is necessary, and ‘build efficiently’ utilises low-carbon construction methods and sustainable design features to reduce both embodied and operational emissions.

Initially, a design proposal for a lagoon was explored to ‘build less’ by eliminating the need to construct a tank. However, calculations proved that the available site footprint would not be large enough to accommodate the surface capacity a lagoon would require.

Therefore, the final design consisted of a new concrete tank, built ‘efficiently’ to drive down carbon within the build phase and throughout the asset’s lifespan. These measures are detailed in the Sustainability section below.

The new tank was designed to be installed alongside the existing stormwater tanks on-site, making use of existing space available, plumbed into the existing pipework and utilise the existing outflow. By using exiting duct routes to carry the ultrasonic transducer cable to the control room, the design saved approximately 100m of new ducting, providing a carbon and cost saving for the client.

[caption id="attachment_32446" align="alignnone" width="1200"] The new and existing storm tanks - Courtesy of Stonbury[/caption]

Designing the tank to work with the existing tanks using gravity removed the need for energy-intensive pump installations. All four tanks were designed to work together, gravity feeding overflows until all were full, and stormwater could overspill into the nearby waterbody. The drainage point on the new tank was designed to be controlled by an actuator, so once flows cease, all remaining water in the tank flushes back through the inlet works, emptying the tank and feeding water back into the processing works. Space for the new tank would be created by demolishing two redundant concrete humus tanks that have been out of service for some time.

The level monitoring and spill-to-river alarm was integrated through an existing programmable logic controller (PLC) and a new mimic page was created on the human-machine interface (HMI) to include the new storm tank.

Challenges

The tank’s construction presented some challenges which were overcome in a way that demonstrated Stonbury’s commitment to environmentally sound and safe practices. The most prominent challenge was the restricted space on the site, in particular, building in this small area while working around live assets and interlinking them.

To manage working in a confined area, pedestrian walkways were put in place to segregate pedestrian-plant interface; Herras fencing was erected around the work area and special routes were made for YW site operatives to gain access to live equipment 24/7.

[caption id="attachment_32444" align="alignnone" width="1200"] The completed storm tank - Courtesy of Stonbury[/caption]

While excavating, the team discovered excessive groundwater and some redundant stormwater services under the new tank footprint. The team safely isolated these by capping the redundant pipe and diverting the existing stormwater pipe to a formed sump within the excavation. This allowed Stonbury to install pumps throughout the duration of the programme to pump the groundwater out safely.

Groundwater was pumped from the site and discharged into a nearby watercourse. Prior to discharge, the water was passed through silt tanks to remove sediments and contaminants, eliminating the risk of pollution. Throughout the programme, turbidity testing was carried out daily to ensure that discharge water consistently met the required environmental standards.

Sustainability

Addressing Stonbury’s commitment to deliver low-carbon, environmentally restorative infrastructure, each element of the project was completed using the most sustainable method practically available.

These included:

Designing the tank in accordance with the Carbon Reduction Curve, which led to the most carbon-efficient design that was practical for the site. Reuse of aggregate materials produced by demolition of the pre-existing tanks within the formation for the base of the new tank. All excavated materials were kept on-site for landscaping. Minimising on-site waste. Minimising fuel usage by ensuring pumps were switched off when not required. [caption id="attachment_32441" align="alignnone" width="1200"] Reinstatement works - Courtesy of Stonbury[/caption]

To achieve sustainability objectives, the project team prioritised the use of hydrotreated vegetable oil (HVO) fuel in all machinery and established an eco-welfare unit for staff breaks. To achieve biodiversity new gain and improve the habitat potential of the site, the reinstatement involved re-seeding grass areas with a mix that supports invertebrates.

During the excavation dewatering process, groundwater was passed through a settlement tank that was regularly cleaned to remove settled solids, and through a sediment filtration sock to ensure it could be discharged in an environmentally safe manner.

Conclusion

The new stormwater storage tank spatially compliments the existing access and tank for client operations and has enabled the treatment works to retain significantly more stormwater on-site to process after storm events. This increased capacity will help prevent untreated overspills into the adjacent ponds, improving water quality both locally and within the wider catchment. The project marks a significant contribution in reducing storm overflow use and safeguard water quality throughout the county’s waterways.

The Seagahan Water Treatment Works (WTW) is located approximately six miles south of Armagh in Northern Ireland and serves communities in Edanveys, Corran, and Roughfort via a single gravity-fed main from the Seagahan impounding reservoir. The Seagahan Treatability Improvements Project is a strategic initiative within the Water Non-Infrastructure work stream, designed to address persistent operational and compliance challenges at NI Water’s 23 water treatment works. Seagahan WTW currently treats an average of 10 million litres per day (MLD), with a design capacity of 16.3 MLD and plays a critical role in regional water supply. Project need

In recent times Seagahan WTW has faced ongoing issues including:

Elevated trihalomethanes (THMs) and turbidity in final water. Inadequate contact time for disinfection. A failing soda ash system. Chlorinated backwash water and backwash capacity issues.

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

[caption id="attachment_26493" align="alignnone" width="1200"] Seagahan WTW & Seagahan Reservoir - Courtesy of NI Water[/caption] Project scope

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

Replacement of the soda ash plant. Installation of automatic coagulation dosing system to analyse trends. New orthophosphoric dosing system. Replacement of valves and actuators. Upgrade of one rapid gravity filter with glass media.

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

Project team

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

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

[caption id="attachment_26484" align="alignnone" width="1200"] BIM model of existing GAC building - Courtesy of Murphy DAWSON-WAM[/caption] Seagahan WTW: Supply chain - key participants Client: NI Water Project manager: Arup Main contractor: Murphy DAWSON-WAM (MDWAM) Process & MEICA designer & contractor: Murphy Process Engineering Civils designer & contractor: DAWSON-WAM Ltd Civils design: RPS Formwork: Raptic Ltd Chemical storage & batch tanks: Spirotech Chemical dosing pumps: ProMinent Fluid Controls (UK) MCC works: Pronto Automation Systems Ltd Static mixer: TPS Filtration Chemical storage tank: Forbes Technologies Limited Air scour blower: AERZEN Machines Design & planning

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

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

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

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

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

[caption id="attachment_26491" align="alignnone" width="1200"] (left) Mezzanine platform: MCC & holding tank and (right) soda ash bulk storage silo - Courtesy of NI Water[/caption] Construction & implementation

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

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

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

[caption id="attachment_26492" align="alignnone" width="1200"] Static mixer chamber roof & CWT1 inlet pipe - Courtesy of NI Water[/caption]

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

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

Process enhancements

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

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

[caption id="attachment_26487" align="alignnone" width="1200"] Soda ash mix tank A & B - Courtesy of NI Water[/caption]

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

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

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

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

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

[caption id="attachment_26488" align="alignnone" width="1200"] Orthophosphoric dosing plant - Courtesy of NI Water[/caption]

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

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

Innovations, cost savings & carbon reduction

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

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

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

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

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

[caption id="attachment_26483" align="alignnone" width="1200"] Soda ash transfer pumps - Courtesy of NI Water[/caption]

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

Embodied carbon avoidance: By re-purposing existing infrastructure rather than constructing a new 100m2 facility, the project avoided significant carbon emissions and capital expenditure - This approach resulted in an estimated carbon saving of 60 to 90 tonnes of Co2e and a cost saving of £350,000 to £500,000. Energy-efficient equipment: The installation of high-efficiency motors helped reduce operational energy consumption - This measure contributes an annual carbon saving of 2 to 5 tonnes of Co2e and an annual cost saving of £216 to £432. Process optimisation: Enhancements in chemical dosing reduced both chemical usage and sludge production - These improvements yield an annual carbon saving of 2 to 10 tonnes of Co2e and a cost saving of £1,000 to £2,000.

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

Project outcomes

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

Based in the Northwest of England, they have strived to build up a brand well known in the marketplace. Janet Waine, Managing Director of Aqua Safety showers explains how important a safety shower is and what is required to meet legal requirements. The Health and Safety at Work Act 1974 states all employees have a safe place to work. In industries and workplaces where employees handle hazardous materials, the importance of having an emergency safety shower cannot be overstated. Accidents can happen, and exposure to chemicals or other dangerous substances can occur unexpectedly, putting workers' health and well-being at risk. By installing a safety shower unit, you are meeting your duty of care to your employees as well as promoting a culture of safety within your workplace. The latest specifications for safety showers state that the shower should deliver tepid water to avoid thermal shock and further injury. The unit should be easily accessible and visible. The best option to achieve this is to install a TS1500L self- contained safety shower. This unit holds 1500L of water which is warmed to 18-20°C and will deliver the required 15 minutes of tepid water both from the shower and eyewash (if fitted). This unit is manufactured from stainless steel and GRP which are all corrosive resistant materials and comes with photo luminous signage as standard. Many optional extras are available to suit site requirements and specifications. A washdown hose reel is a piece of equipment that should be installed at the side of the safety shower so the area can be hosed down after any spillage. Aqua safety showers offer a range of retractable wash down hosereels which are built into a heavy-duty GRP heated cabinet. The cabinet is mounted on a stainless-steel pedestal. [caption id="attachment_9955" align="alignnone" width="1200"] A washdown hose reel[/caption] A safety shower is an asset and should last for approximately 20 years. To ensure this long service life of this piece of equipment the unit should be tested weekly to ensure correct operation and serviced ideally every 3-6 months. At Aqua, we understand the importance of keeping your safety shower in optimal condition to ensure the well-being of your workforce. By ensuring a service contract is in place you are investing in the longevity and reliability of your asset. Aqua Safety showers offer a complete maintenance package for any model of safety showers and offers site surveys should this be required. Conclusion Having an emergency safety shower in the workplace is not just a legal requirement; it is a vital investment in employee safety. By providing immediate access to decontamination, safety showers play a crucial role in preventing and reducing injuries resulting from exposure to hazardous materials. Moreover, they ensure compliance with regulations, enhance emergency preparedness, reduce costs, and promote a culture of safety within the organization. Employers should prioritize the installation, maintenance, and regular training on the usage of safety showers to create a safer and more secure work environment for their employees.     For more information: +44(0)1942 318096 | www.aqua-safety.com

Reliable Emergency Response Regular maintenance ensures that the safety shower is in proper working condition and ready to be used when needed. By conducting routine inspections and maintenance activities such as testing water flow, checking water temperature, and inspecting valves, any potential issues can be identified and addressed promptly, ensuring that the safety shower will function reliably during an emergency. Regular inspection and testing also ensures the area around the safety shower is always checked and clear from obstructions. Employee Safety The primary purpose of a safety shower is to provide immediate decontamination in case of exposure to hazardous substances. Regular maintenance helps ensure that the safety shower is fully operational and ready should it be needed. Compliance with Regulations Safety showers are often subject to regulatory requirements and standards that specify their maintenance and inspection. By adhering to these regulations, companies demonstrate their commitment to compliance and workplace safety. Regular maintenance helps ensure that the safety shower meets the required standards and ensures the company is meeting its legal requirement. Extended Lifespan A safety shower should have a lifespan of approximately 15-20 years.  Proper maintenance and care can significantly extend the lifespan of a safety shower. By promptly addressing any issues, replacing worn-out components, and conducting regular cleaning, you can prevent major breakdowns and costly repairs. Regular maintenance helps keep the safety shower in optimal condition, reducing the need for premature replacements. Conclusion Maintaining a safety shower is essential for its reliable performance, employee safety, regulatory compliance, and overall operational readiness. Regular maintenance and inspections help identify and address any issues promptly, ensuring that the safety shower is always ready for use during emergencies.     For more information: +44(0)1942 318096 | www.aqua-safety.com