Supply Chain - Asset Maintenance & Rehabilitation - Pipeline Rehabilitation & Cleaning

Potters Way, located in the Fengate area of Peterborough, is a recent housing development next to the A1139. The development was built on the grounds of the former Fengate Water Recycling Centre (WRC) which closed in 1988 following the construction of the Flag Fen WRC. In early December 2018, Anglian Water became aware of the collapse of a section of 1500mm diameter concrete sewer pipe in Potters Way when a small hole was found after a customer used a ride-on lawn mower over the area. Temporary repair works were undertaken by the Integrated Operational Solutions (IOS) Alliance - a partnership between Anglian Water, Kier, Barhale and Morrison Utility Services - while a permanent fix could be designed and implemented.

Background

By the end of December, the IOS Alliance had installed a temporary repair using a vacuum excavator to safely clear the collapsed pipe before using half-pipe and canvas to seal the collapse. The area was also fenced off to prevent pedestrian access and ensure site safety. During this period, Anglian Water received several complaints from customers over the odour created by the collapse. Following meetings with the residents, Anglian Water’s Water Recycling Networks (WRN) team further sealed the excavation and installed carbon filters to the air valves. At the same time, the team repaired holes found in the rising main pipework at the nearby tower. The site was then handed over to the Anglian Water @one Alliance to implement their repair solution with @one partner company Barhale engaged as principal contractor. [caption id="" align="alignnone" width="1200"] Installation of the overhead diversion - Courtesy of @one Alliance[/caption]

Finding a solution

One of the challenges presented in finding a solution for this project was the high flow rate of the pipework, with modelling of Potters Way showing flow rates of 3,700 litres per second in the event of a 1 in 30-year storm. Downstream of Potters Way, this rises to 4,000 litres per second. To make the matter even more complicated, the pipe featured several significant bends along the affected route that increased the difficulty of finding an adequate solution. An extensive survey of 2.8km of sewer identified 1.79km of concrete sewer pipework ranging in diameter from 1050mm to 1950mm had a condition grade of either 4 or 5. All these pipes were identified as having been subjected to a hydrogen sulphide (H₂S) attack which had caused the significant deterioration. The @one Alliance set out to repair an area of the network by covering a key 500m of pipework which serves the majority of Peterborough.

Potters Way Sewer Rehabilitation: Supply chain

• Project delivery: Anglian Water @one Alliance
• Temporary repairs: Integrated Operational Solutions (IOS) Alliance
• Principal contractor: Barhale
• Over pumping: Vanderkamp UK
• GRP pipe lining: Amiblu Norway AS
• Lining & manhole repair: OnSite Central Ltd
• Specialist CCTV Survey: Bright Innovations Group
• Foam concrete: GS Foam Concrete
• Diamond cutting: SCS Ltd
• Cover slabs: FP McCann Ltd
• Temporary works/shoring: Groundforce

Pipe rehabilitation

The @one Alliance solutions team opted for a multi-stage solution due to the complex nature of the pipework and the compact area the teams would be working in. In order to repair the sewer, it was decided that a mix of CIPP (cured in place pipe) and GRP (glass reinforced plastic) lining would be used. The majority of the rehabilitation was completed using CIPP lining which allows the lining to be inserted into the shell of the existing, damaged pipework where it is then pressurised and cured in place with ultraviolet (UV) lights. The CIPP relining was split into eight sections covering approximately 360m of the repaired pipeline. At 1375mm in diameter, this installation was the largest diameter CIPP liner that the @one Alliance had ever installed. Six of the eight lengths of CIPP were installed under the A1139.

Over pumping

In order to fit the CIPP liners, the team utilised an over pumping set up capable of 250 litres per second (l/s). By using bungs at split manholes on the nearby Bourges Boulevard, the team could redirect the flow and use the pumping set up to divert the rest of the flow. The over pumping solution was provided by Vanderkamp UK who had remote monitoring capabilities from the Netherlands and provided the site teams with a mobile app allowing them to see real time data giving them advanced warning of increased flows which would require the removal of the bungs. Without this passive flow management, the over pumping setup would have needed to be able to cope with an excess of 2,000 l/s. The set up was made up of two pipe bridges 350mm in diameter and 5.5m high to allow clearance for high-sided vehicles.

GRP lining

Alongside the CIPP lining, the team also used GRP lining on a 48m section of 1500mm diameter sewer executing the rehabilitation in live flow conditions of approximately 850 litres per second; the first time the @one Alliance had installed GRP lining in live flow conditions. [caption id="" align="alignnone" width="1200"] (left) Live flow conditions and (right) inserting a new section of Amiblu Norway AS GRP pipe - Courtesy of @one Alliance[/caption] Operating in live flow removed the necessity to install an additional over pumping solution that would have dealt with 95% of Peterborough’s sewage as it combined into one flow towards Flag Fen WRC. In order to commence the GRP lining, the crown of the pipe was removed on a bend and concrete platforms were constructed on either side ensuring a safe working area. A pipe pusher attachment was then used to insert segments upstream and downstream from the bend location. Finally, a prefabricated GRP bend section was installed and connected to straight sections. To safely cut the existing mains the team needed to excavate an area of 6m x 4.5m with a depth of 3.5m. While having to excavate in an urban area is an option the team would have liked to have avoided, the next best solution to the live flow repair would have included installing a temporary pumping station that would have taken up all of Potters Way’s parking and grass area requiring 10 pumps and a 10m x 7m x 7m temporary wet well to complete the required repair. This would have been a major inconvenience for residents and would have seen an increase in the overall cost of the project of 200%.

Amiblu relining pipes to protect sewer networks from H₂S attacks - Courtesy of Amiblu Norway AS

Manhole rehabilitation

As part of the pre-work checks, it was identified that eleven manholes along the section of pipework required rehabilitation of various levels with the most severely affected requiring structural repair as a result of H₂S attacks. Core samples were taken from one manhole which identified that in some places, more than 150mm of concrete had been lost to H₂S attacks with no rebar remaining in any of the samples. To repair the manhole, the team used a concrete spray to bring the walls back to their original 250mm thickness, once this had cured a primary and finishing layer were added to ensure full protection against H₂S attacks in the future. A new cover slab was also installed after the original was removed to provide access to the manhole, made of precast concrete the slab was also treated for H₂S protection. [caption id="" align="alignnone" width="1200"] (left) H₂S attack on a manhole and (right) inside a relined section of pipe - Courtesy of @one Alliance[/caption]

Challenges

Weather provided a significant challenge for the implementation of the solution as the site experienced an unusually heavy rainfall. Flow rate analysis for Flag Fen WRC shows that in the previous five years the average rainfall for the area fell between 35mm and 60mm. August 2020 saw average rainfall of 137mm. Because of the heavy rainfall several weather warnings were issued placing all CIPP lining activities on hold. The impact of the weather was so severe the flow of water increased from its usual 850l/s to 4,000 l/s in just 10 minutes. In order to reduce the risk of flooding outside the Magistrates Court the bungs were deflated, and the flow reverted. Due to the innovative combination of flow diversion and overpumping used in the CIPP lining the impact of the delay was significantly reduced compared to if the team had used the temporary pumping station solution.

Rising mains issues

During the repair of the sewer the @one Alliance became aware of complaints from the residents regarding the twin rising mains on Potters Way which used to feed into the old Peterborough STW and was diverted into the new gravity sewer discharging into Flag Fen WRC. The primary complaint from customers was the odour produced by the rising mains. The old Peterborough STW was sold for development and the rising mains tower was marked for removal. In early 2022 the @one Alliance returned to Potters Way removing the rising mains and installing a pumping station kiosk removing the odour and significantly reducing the visible profile in the area.

Result

Anglian Water invested £2.8m into the Potters Way project which will now allow customers across Peterborough to continue to use their taps and flush their toilets without second thought. The relining of the sewer network has ensured the network in the Potters Way area is now protected from H₂S attacks for the next 50 years. Colin Handley, Construction Manager said:

“There was fantastic team collaboration between our Tier 2 Supply Chain Partners, the Principal Contractor (Barhale) and the @one Alliance, making it one team delivering the programme. The teams worked tirelessly to monitor the smells and reduce odours, whilst working in open excavations. They purchased additional fans and diverted rising mains to lower H₂S and to allow the teams to work safely.”

Sprowston Blue Boar Lane Rising Main in Norwich plays a crucial function in management of wastewater for the local community. The rising main connects the Sprowston Blue Boar Lane Pumping Station to the sewer network; facilitating efficient wastewater transport. The pipeline’s strategic location near housing developments, a roundabout, and a Tesco supermarket and fuel station underscores its importance to public health and safety. The region’s growth and the rising main’s proximity to high-traffic zones emphasise the need for a reliable and resilient infrastructure.

The issue

As assets age, they start to work less efficiently than they did at their installation. Anglian Water Service had recently noticed this within the Sprowston Blue Boar Lane Rising Main, as it had experienced multiple bursts in recent years, including incidents on November 18, 2020 and August 20, 2021. These failures occurred near critical infrastructure, including residential areas and a busy roundabout adjacent to a Tesco supermarket and delivery bay.

The existing 450mm glass reinforced plastic rising main’s deteriorated condition necessitated immediate action. Additionally, the aging infrastructure had a rough internal surface, contributing to inefficiencies in flow and elevated operational risks. The bursts posed significant risks, including potential pollution events through contamination, which is a risk to the public health of the surrounding area.

Design considerations

Anglian Water’s @one Alliance sewer rehabilitation team acted quickly to come up with a solution for this issue; realising that a comprehensive rehabilitation plan was required to address the identified issues to ensure long-term reliability and compliance with performance standards. To complete this, the project’s execution followed a systematic approach to minimise disruptions and maintain service continuity.

[caption id="attachment_19175" align="alignnone" width="1200"] omplex overpumping arrangement - Courtesy of Anglian Water’s @one Alliance[/caption]

Thorough assessments were undertaken to ensure the most effective and future-proofed solution was selected, so during the design phase, the Anglian Water @one Alliance team carefully explored multiple options to determine the best approach for this project. Replacing the existing GRP pipe with a brand-new PE pipe along Blue Boar Lane was initially considered, however, trial hole investigations quickly revealed the area’s significant congestion of utilities, including gas mains and electric cables, which posed substantial risks to the project.

Further construction techniques were evaluated, but ultimately the installation of a 9mm thick, water-cured liner within the existing pipe was determined to be the optimal solution, offering a practical and efficient way to navigate the complexities of the site.

The solution required maintaining a flow rate of 142 l/s and thanks to the smoother surface of the new liner, hydraulic modelling confirmed that there was no adverse effect from the reduced bore resulting from the relining process.

Hydraulic modelling also accounted for maximum and minimum pressure conditions, including surge pressures during operation and pump trips, and it was determined that the liner needed to withstand pressures of up to 5.15 bar and negative pressures down to -0.5 bar.

The final design not only met hydraulic modelling criteria but also ensured sufficient pressure handling, making it robust and efficient under operational conditions.

Blue Boar Lane Rising Main: Supply chain - key participants

• Client: Anglian Water
• Project delivery: @one Alliance
• Bypass pipework: Vanderkamp UK
• Cured in place relining: OnSite Central Ltd
• Crane hire: Crowland Cranes

Temporary works

The initial challenge the team faced was the need for the sewer to be empty while the relining rehabilitation works took place. To resolve this challenge and ensure uninterrupted service to customers during construction, a temporary 450mm diameter, above-ground pipe needed to be installed to divert sewage flows, complete with pipe bridges at road crossings and entrance points. The temporary pipeline allowed the existing GRP pipe to be isolated and the rehabilitation could commence.

[caption id="attachment_19176" align="alignnone" width="1200"] Complex overpumping arrangement - Courtesy of Anglian Water’s @one Alliance[/caption] The installation of the temporary pipework was a significant undertaking, and one that required close collaboration with Vanderkamp UK. Working together, the @one Alliance/Vanderkamp UK team considered sustainable solutions to mitigate flows and ensure the continued integrity of Anglian Water’s infrastructure.

Liner installation

With the overland pipework in place, the team drained the existing GRP rising main and undertook CCTV surveys to assess its condition.

The works required the installation of a 9mm thick, water-cured liner within the existing pipe, which would create a smooth and durable interior surface with improved hydraulic performance. Alongside the installation of the new liner, a new air valve at the high point near the Tesco loading bay was installed to optimise the pressure going into the pipe.

Once the work was complete, the relined pipe was reconnected to the network and tested and commissioned for performance before being handed back to Anglian Water. The site team then decommissioned the overland pipework and restored the area back to its original condition.

The team relined 680m of the existing 450mm GRP rising main, providing a robust solution which will last for many years to come.

Benefits of the solution

The rehabilitation of the Sprowston Blue Boar Lane Rising Main delivered numerous operational, environmental, and community benefits.

• The installation of the 9mm thick pressure liner significantly improved the rising main’s durability and hydraulic performance for many years to come. The smoother interior surface reduced the resistance, enhanced the flow efficiency and minimised the energy consumption. By installing the new air valve, optimal pressure was maintained which reduced the risk of future bursts.
• The solution also mitigates the risk of environmental contamination from wastewater spills and supports environmental compliance with regulatory standards.
• The temporary overland pipework ensured uninterrupted service to our local community and the water-cured relining method was a cost-effective solution compared to complete replacement; minimising excavation and associated costs.
• Thes solution provides longevity and resilience by providing over 50+ year’s lifespan of the pressure liner, which in turn reduces the need for frequent maintenance & also lowers the lifecycle costs.

Conclusion

By implementing innovative technologies and meticulous planning, the £1.5m project addressed critical operational challenges while minimising environmental and community impacts. The success of this infrastructure improvement project ensured continuity of service and long-term reliability, safeguarding the region’s wastewater infrastructure for decades to come.

The Saltcoats Rising Main project involved upgrading just over a kilometre of existing pipe on the most burst-prone section of the rising main, which stretches between the towns of Saltcoats and Stevenston in North Ayrshire. The rising main was originally installed in 1992, and it runs approximately 3km from Saltcoats WwPS towards Stevenston WwTW. The existing main is a 700mm diameter ductile iron (DI) pipe, ranging from two to five metres in depth, conveying a flow of around 500 l/s.

Background

The driver for this fast-tracked project was that the main had burst on various occasions, with four bursts before Caledonia Water Alliance’s (CWA) involvement and a further burst during the design phase.

The failure on the pipe became evident along the invert, with noticeable ‘channelling’ discovered after taking cut-outs during the repair works. There is a bathing water nearby and bursts were causing the pumping station to spill and have a direct impact on the water, prompting Scottish Water to seek permanent solutions to improve the pressure main’s functionality instead of continually responding to leaks.

[caption id="attachment_13076" align="alignnone" width="1200"] (left) Aerial view of the project and (right) rising main failure - Courtesy of Caledonia Water Alliance[/caption]

Project scope

• Lining of the first 1km of existing 700mm diameter DI rising main from Saltcoats WwPS.
• Installation of cured in place pipe (CIPP) lining by hot curing.
• Installation of one air valve and one scour valve. The scour valve to be relocated off carriageway for future ease of access and maintenance.
• Excavation of five lining pits to enable lining in both directions.
• Two  bypass installations to enable over pumping of all flows during lining works.
• Planned shutdown to install valve arrangement for bypass.
• Installation of approximately 1km in length of overland 700mm steel pipes.

Site investigation

Given the environmental impact of bursts to the nearby bathing waters, the project started moving quickly and CWA were engaged to review potential solutions. While reviewing the requirements for a potential offline replacement, it became apparent that this would take some time and require multiple third-party approvals before any work could take place.

It would also involve finding a suitable location for a new pipe, which would involve executing the works through an existing golf course and through the only access road in and out of a busy caravan park. To limit the impact of the works and reach the site quicker, Scottish Water agreed to use a trenchless solution and re-line the existing rising main. Scottish Water instructed Caledonia Water Alliance to focus on the first 1km of the main, as this would cover the section of previous bursts to date.

This would make the scope more achievable in lieu of the bathing season approaching, given the location of the remainder of the pipe.

[caption id="attachment_13074" align="alignnone" width="1200"] Pipe delivery - Courtesy of Caledonia Water Alliance[/caption]

Project summary

• Project name: Saltcoats Rising Main
• Project cost: £4m
• Start date - design: 1 November 2022
• Start date - construction: 31 March 2023
• Completion date: 27 October 2023

Planning

With the agreed solution of lining the pipe now in place, the focus turned to getting on site as quickly as possible. This meant fast-tracking numerous stages, such as ground investigation and detailed design, and instead progressing with a high-level detail of the proposal, with various assumptions in place. The main issue which arose was how to manage the flows.

Caledonia Water Alliance proposed different options to SEPA, ultimately suggesting that they could turn the pumps off and tanker/spill the flows while working on lining the pipe. This would have been the quickest solution but would involve the rising main being offline for several months, which SEPA, as a regulator, could not accept.

SEPA did however appreciate why Caledonia Water Alliance were asking the question. Caledonia Water Alliance had anticipated this being the case with the only other option to bypass the flows with an overland pipe while working on the existing main. However, this posed issues - mainly around laying 1km of 700mm diameter pipe over a golf course and how they could cross a busy road. Given the services within the road and the time constraints, Caledonia Water Alliance could not bury it, even partially.

[caption id="attachment_13070" align="alignnone" width="1200"] Assembly of overhead pipe bridge - Courtesy of Caledonia Water Alliance[/caption]

This led to the proposal of an up-and-over bridge crossing. Caledonia Water Alliance was initially reluctant, given the visual impact this would have but, realistically, had no other choice. In the end, this worked out well, through extensive communications with the local residents, businesses, and caravan park, all agreeing the work was necessary to rehabilitate the rising main. The next challenge was to get the 1km bypass installed and operational before the bathing season beginning on the 31 May 2023.

From receiving the project at the end of October 2022 and starting on site in March 2023, Caledonia Water Alliance was able to collaborate with Environmental Techniques Ltd to design a cured-in-place liner with pit locations; working alongside their specialist subcontractor Selwood, to develop the overland bypass pipe.

As above, Caledonia Water Alliance went to site with some assumptions of the rising main location and depth, so they knew there would be changes as the project developed on site.

Saltcoats Rising Main: Supply chain - key participants

• Project delivery: Caledonia Water Alliance
• Trenchless rehabilitation & liner design: Environmental Techniques Ltd
• Civils subcontractor: Jacks1 Civil Engineering
• Underpressure connections: Swan Pipelines
• Scaffolding: AHL Scaffolding
• Temporary works/shoring: Groundforce
• Water supply: Enviroclean
• Liner supply: Insituform
• Bypass pipework: Selwood

[caption id="attachment_13073" align="alignnone" width="1200"] Bypass pit showing pipework cut out and a new ‘T’ piece and valve arrangement - Courtesy of Caledonia Water Alliance[/caption]

Temporary bypass

The first part of the work, after establishing the site, was to install the temporary bypass. The bypass utilised a 700mm diameter flanged steel pipe, bolted together. This was strung out from a bypass pit adjacent to Saltcoats Pumping Station, approximately 1km downstream.

This required a tremendous effort to deliver a large quantity of pipework, drop it in place and bolt it together whilst working on both bypass pits at either end of the 1km section of pipe. The team completed the works on the bypass on time before the bathing season. With this now operational, CWA ensured the safety of the first 1km of the main from potential bursts.

Liner installation

The liner chosen was a cured-in-place pipe liner (CIPP) as this would provide the structural capacity of the host pipe. CIPP lining has been extensively used throughout the UK to repair failing sewer pipes, prevent infiltration and to add structural strength where required.

Designing CIPP liners for pressurised pipe systems presents unique challenges that differ significantly from their application in gravity-fed sewers. In pressurised systems, the liner must withstand not only external forces such as soil, groundwater, and traffic loads but also the continuous internal pressure exerted by the fluid within the pipe.

Additionally, the liner must also be able to withstand negative internal pressures, or vacuum conditions, which can cause the liner to experience inward forces, particularly near joints and bends. The design had to account for these vacuum scenarios to ensure that the liner remains stable and securely bonded to the host pipe, preserving the structural integrity of the pipe under varying pressure conditions.

[caption id="attachment_15903" align="alignnone" width="1200"] Liner installation - Courtesy of Caledonia Water Alliance[/caption]

The liner was designed with the operating and supplied test pressures of the existing rising main. The number of known bends, as well as the potential for more unknown bends, meant that the hot water curing was a more suitable process for this project as the liner would invert itself under the pressure of the curing water, navigating around the bends automatically.

A scaffold tower was installed at the installation pits to secure the end of the liner and to ensure enough vertical height to allow the water pressure to invert the liner through the length of pipe required. The hot cure process utilises a hot water boiler to raise the temperature of the curing water which begins the process of hardening the resin.

The liner provides a 60-year design life, similar to installing a new pipework, but with significantly less digging requirements and waste production.

[caption id="attachment_15902" align="alignnone" width="1200"] Drone image showing the scaffold tower and the liner installation operation underway - Courtesy of Paul Milligan, Caledonia Water Alliance[/caption]

No-dig technique

The decision to use trenchless relining methods was primarily driven by the need to minimise the number of excavations, significantly reducing disruption and environmental impact. In Saltcoats, this approach required only five lining pits and two bypass pits along the existing rising main, demonstrating the efficiency of trenchless technology compared to traditional dig-and-replace methods. One of the key benefits of trenchless relining is the reduced need for extensive excavation, which minimises surface disruption to roads, traffic, and the surrounding environment. This is particularly in Saltcoats to minimise disruption to the local communities, golf course and caravan park. By using trenchless techniques, the project can be completed faster with less noise, dust, and inconvenience to residents and visitors to these areas.

For the bypass pits, existing pipe sections were cut out, and new T-piece and valve arrangements were installed. This allowed for the connection of temporary bypass pipes, enabling the flow to be managed through valve operation without interrupting service. The trenchless approach also reduces the risk of encountering unforeseen underground utilities, which can lead to costly delays and repairs.

Overall, trenchless relining offers a safer, more efficient, and less invasive solution for repairing and upgrading pipeline infrastructure.

Conclusion/update

The project was completed successfully on site and within the proposed programme, despite coming across some major obstacles on site. Once the lining was completed, it was inspected, tested, and finally put into commission by transferring the flows back into the newly rehabilitated main.

[caption id="attachment_13071" align="alignnone" width="1200"] CCTV output pre and post lining - Courtesy of Caledonia Water Alliance[/caption]

Following successful commissioning, the rising main was run for a period of 48 hours without any defects. After this time, Caledonia Water Alliance was able to start dismantling the bypass pipe, removing it from site and reinstating the area.

Undertaking the Saltcoats Rising Main Rehabilitation Project was a significant effort by all involved to first install and have the bypass pipe operational before the bathing season, and then to have the existing main rehabilitated and working within the timescales which Caledonia Water Alliance provided Scottish Water at the start of the works.

This was particularly impressive given the fast-track nature of the works and getting a large-scale project to site quickly. There is now a Phase 2 and 3 proposed for the remainder of the rising main to Stevenston WwTW to rehabilitate it over its entirety. These will be looked at over the next 2 to 3 years.

As assets age, they start to work less efficiently than they did at their installation. Anglian Water proactively CCTV surveyed the sewers and found evidence of hydrogen sulphide attack, which corrodes concrete sewers resulting in weakening of the pipework and eventual collapse. In September 2023, the @one Alliance Sewer Rehabilitation Team completed a project in Grays, Essex, off the A1012 Treacle Mind Roundabout near the A13, where they rehabilitated over 840 meters of 900mm concrete sewer pipe along Lodge Lane - a crucial lifeline for a highly populated residential area.

Planning

From the outset, it was clear that this undertaking would require an innovative approach beyond conventional sewer lining and over pumping techniques. Two main challenges were faced by the project team.

The first challenge was to determine how to rehabilitate a 324m manhole-to-manhole stretch at this massive diameter at such a busy location and under tight highways restrictions. The team realised that they needed to trace the line and identify an optimal location for a new access point - a crucial step to break down the sewer into more manageable sections. Considering that the sewer crosses Lodge Lane halfway through, added with the need to avoid existing services and our bypass pipework, it became apparent that this was not a viable option.

[caption id="attachment_13360" align="alignnone" width="1200"] Overpumping pipework - Courtesy of @one Alliance[/caption]

The second challenge the team faced was the need for the sewer to be empty while the rehabilitation works took place. The team decided that in order to resolve this challenge, they needed to install a temporary above-ground pipe to divert the sewage flows.

This job was a significant undertaking, and one that required close collaboration with Vanderkamp UK. Working together, the @one Alliance/Vanderkamp UK team considered sustainable solutions to mitigate flows and ensure the continued integrity of Anglian Water’s infrastructure.

To manage flows and ensure uninterrupted service to customers, temporary connections were established on the existing 600mm and 375mm dia. rising mains within the Treacle Mine Roundabout. These mains, originating from the Stifford Corran Way and Stifford Clays Pumping Stations, require pumping of up to 350 l/s.

The aim was to maintain seamless flow and mitigate any potential flood risks, so the bypass was routed through in-line duty/standby booster pumps strategically positioned within the roundabout. This innovative approach eliminated the need for suction pits or wet wells. Through extensive modelling, the team identified the need to incorporate booster pumps, as the existing pumping stations could not pump the additional 1km of 500mm bypass pipework, which included 16 pipe bridges and hoppers.

Vanderkamp UK undertook continuous and meticulous remote monitoring which ensured the successful execution of this complex and critical project.

[caption id="attachment_13366" align="alignnone" width="1200"] Vanderkamp UK’s temporary overpuming pipework while OnSite Cental undertake the CIPP lining works - Courtesy of @one Alliance[/caption]

Grays Sewer Rehabilitation: Supply chain - key participants

• Client: Anglian Water
• Project delivery: @one Alliance
• Bypass pipework (1km of 500mm pipe): Vanderkamp UK
• Cured in place relining: OnSite Central Ltd
• CIPP liner supply: IMPREG GmBH
• Traffic management: TBF Traffic

The 324m manhole to manhole stretch

Addressing the first challenge of rehabilitating the large manhole to manhole stretch, the team collaborated closely with Tier 2 Supply Chain partner OnSite Central Ltd, to prove a cured in place pipe (CIPP) relining solution. The @one Alliance challenged OnSite to develop a game-changing method that would enable a one-shot installation of the 324m length.

After exploring various options, including a single-cure installation that posed complications due to power cables, a 50/50 cure approach was selected, partially curing the liner in both directions.

To ensure the liner’s integrity throughout this process, OnSite Central Ltd ingeniously employed special sluice bags to keep the liner inflated while moving the light train to the other manhole; effectively preventing any shear damage to the liner during the transition between cured and uncured sections.

[caption id="attachment_13362" align="alignnone" width="1200"] OnSite Central’s CIPP lining operation - Courtesy of @one Alliance[/caption]

The deployment of specialised equipment, including a large 20-ton winch, a larger roller bed, crane pads, and sluice bags, incurred additional costs, however, savings totalling approximately £35k included avoiding the need for an additional liner installation, a week of over-pumping, and substantial running costs. Additional significant savings were gained by removing the requirement for a new 6m deep access point and extended road closures.

In terms of sheer length, this installation now holds the record as the longest the Anglian Water @one Alliance Sewer Rehabilitation Team has ever undertaken. OnSite also suspect that it might even be a record-breaker for UV installations in the UK, if not globally! Typically, cable length restrictions cap such installations at around 300 meters, making this 324m achievement truly exceptional!

Challenges

As with any project, challenges arise. Added to the previous challenges mentioned, the team had plenty more to overcome.

Ensuring resources: Learning from concurrent @one Alliance projects, from the outset, the team knew that they needed to ensure resources were available for the project to commence, therefore early resourcing was required to overcome issues on programme later down the line.

Avoiding planning issues: Once the project started, the tight highways restrictions throughout and multiple live permits in the area could have caused planning issues if the team had not realised these early and planned for them at the start of the project, so they worked with Highways early to identify a suitable working window.

[caption id="attachment_13363" align="alignnone" width="1200"] Traffic management during the works - Courtesy of @one Alliance[/caption]

Emergency road closure: Another issue was having to emergency-close Lodge Lane due to two leaks across the pipe bridges. The team identified these by using treated final effluent to ensure no pollution events would occur. To resolve this issue, an emergency road closure was put in place on Lodge Lane for 2 hours from 8-10 PM in order to safely access the pipework at the leaks and tighten the bolts. After collaborations with Highways the closure in place safely put in place.

Additional cleaning: Once flows had been diverted and a detailed CCTV survey was undertaken, it was apparent that more cleaning of the sewer pipe was required, taking longer than was originally anticipated. In order to claw this time back and ensure the project completed on time, the team installed two liners in a week. To do so, the final liner installation needed to be extended into the weekend. This required an adjustment to the road closures on Windsor Avenue which was agreed with Highways and communicated to the local residents.

Avoiding potential issues: Challenges do not only affect the project team; they also affect customers. The team was made aware of visibility issues due to the temporary pipework obstructing the view from a junction, creating a potential blind spot. Responding promptly to feedback from the public, the team worked with the Highways Inspector to install temporary mirrors and mitigate the issue.

Customer engagement

The @one Alliance has a clear purpose to bring environmental and social prosperity to the Anglian Water region, and this is dones by ‘Making Today Great – every day, in every interaction’.

[caption id="attachment_13365" align="alignnone" width="1200"] Customer information boards - Courtesy of @one Alliance[/caption]

The @one Alliance was aware that the work at Grays would impact customers throughout the project lifecycle, so processes were put in place to effectively communicate with customers across the area in a variety of ways.

• Open day: On April 26th, 2023 an open day was hosted at Stifford Parish Hall to give the community the opportunity to meet the team and ask any questions or share any insights before the project began to ensure they had a clear idea of the plan for the project.
• Communications: Customers were notified about the works via letters, emails, SMS campaigns and a dedicated scheme board. In total, over 1,444 letters and 970 emails were sent to residents on top of 13 SMS campaigns which resulted in 2,755 customers receiving text messages to let them know of specific road closures and project updates.
• Social media: Projects updates were regularly updated on Anglian Water’s “In Your Area” website for customers to view and on its Facebook page. The Facebook page reached 63,387 customers in total throughout the project.
• CSAT score: A record number of 9+ scores were received for a scheme with a resulting in a 9.18 CSAT score.

Meticulous planning ensured customers were aware, questions were answered, and feedback was received. Overall, customers have praised the work that has been undertaken; emphasising the minimal disruptions and their appreciation for the use of temporary traffic lights.

Outcome

The works started in June 2023 and completed in September 2023 with the removal of the temporary pipe bridges and traffic lights. Over 840 meters of 900mm sewer pipe have been successfully rehabilitated along Lodge Lane. The project was delivered on time, and gained positive customer feedback, positive relationships with the local council and Highways authorities and a great working relationships with our Tier 2 suppliers Vanderkamp UK and Onsite.

Stockton Lane is located in the north-east area of York and the water supply zone for this area is made up of approximately 21km of water main; 80% of which is metallic and 20% is plastic. Over the last 3 years Yorkshire Water have seen an increase in mains failure due to the ageing infrastructure and the supply zone is ranked in the top 5 areas for proactive capital works. As part of the utilities’ drive to proactively improve the network in Year 4 of AMP7, Yorkshire Water started investigating its options to improve its position on mains repairs, reduce leakage and customer contacts.

Undertakings

Yorkshire Water instructed Morrison Water Services to look at delivery options to maximise performance benefits as well as delivering best value for money for customers. After carrying out hydraulic modelling, mains sample tests and site surveys, the proposed delivery plan was to target the mains in the worst condition by lining 6,090m of water main utilising a lining rig from SCHUR-BPH Ltd.

Lining product selection

Yorkshire Water have been lining water pipes on its network since the 1960s; originally using cement mortal liners and more recently (from 2006) using polymeric spray liners. For Stockton Lane, Resiline 320, a third-generation aliphatic poly-isocyanate material of the same family of in situ lining products, was used. It is one of only a few DWI Regulation 31 approved lining materials in the UK. Some of the benefits it brings are:

• It is moisture tolerant.
• It can be applied from 1mm to 9mm in passes of up to 3mm for non or semi-structural lining.
• It has a low exotherm, which means it avoids shrinkage during product curing.
• It offers long term tensile and flexural creep rupture strengths.
• It enables reduced thickness linings to provide enhanced long-term performance (at least 50 years).

[caption id="attachment_11202" align="alignnone" width="1200"] SCHUR-BPH lining rig - Courtesy of Yorkshire water[/caption]

The lining process

To start the lining process, excavations pits are created to ensure that there are locations for the cleaning process and for the lining head to be inserted into the main to carry out the lining. The cleaning process starts by isolating the water main at two valves and using a hydrant to drain the water main. Once the water main is drained, the Whirlwind is used.

The Whirlwind cleans the main by blowing down swabs, vortexes of air, and stones, that will scratch off any excess materials and dry the pipe; ensuring that the pipe is in a suitable condition to begin the lining process. The condition of the cleaning is checked by carrying out CCTV surveys on the main. The material is applied by using a lining rig from SCHUR-BPH Ltd.

The rig comprises two paint drums that hold the base and activator paints, which are pumped and heated to the optimum temperature required (300 Celsius) to apply the material onto the pipe. A hose situated at the front of the rig holds the base and activator tubes, and this is pulled through the pipe allowing the lining material to be sprayed onto the pipe interior.

The rig uses a computer system to ensure that each specific water main is lined to the required thickness - for the Stockton Lane Rehabilitation Project, the paint application setting is 3mm due to the works being semi-structural. As well as monitoring the paint thickness, the rig also monitors the flow rate of the lining application and the temperature. If any of these factors drop below the thresholds of + or – 5% of the thickness, an alarm will raise, and the rig will shut off as the application of the material will not be to the required standards.

[caption id="attachment_11200" align="alignnone" width="1200"] (left) Ling rig in operation, (top right) cleaning and (bottom right) spray lining - Courtesy of Yorkshire Water[/caption]

Stockton Road, York, Water Mains Rehabilitation: Supply chain

• Client: Yorkshire Water
• Main designer/contractor: Morrison Water Services
• Lining rig: SCHUR-BPH Ltd
• Resiline 320 pipeline coating: Resimac Ltd

Resiline 320 lining material

The lining material is made up of two paints; the base and activator, which are combined to make the Resiline 320 material. The paint is mixed by using a lining head that spins at 9000 rpm and applies it onto the pipework.

To ensure that the paint is mixed correctly, the operatives take dip cards. This is a visual check to ensure that the paint is of the correct blue colour and is not brittle, meaning that is it suitable for lining. Once these checks have been completed, the lining head will be guided into the pipe, and it will be electronically pulled through by the lining rig.

The distance that can be lined per day depends on the size of the main. On the Stockton Lane project, approximately 90m of the 3” mains were lined per day; and up 110m of the 4” pipe.

Once the lining head has exited the pipe, cap ends are reapplied and a curing period of an hour is undertaken. After 15 minutes, the water mains can be inspected via CCTV. These checks are carried out are to ensure that the lining is uniform, there have been no misses over joints, fittings etc, and that there is no unmixed material as this would result in the lined section having to be replaced. Once approved by the client and the hour cure time has passed, the water main will be put back into commission and water quality samples will be taken.

On Stockton Lane, all of the above processes were undertaken on a daily basis. As part of the DWI allowance for water mains shut off periods, all the work had to be carried out within 2 hours and 59 minutes. On a good day, the work left the site team a window of between 10-20 minutes due to the process being very vigorous. If there was a risk of the time-frames not being met, decisions were made early enough to ensure that customers are not affected.

[caption id="attachment_11201" align="alignnone" width="1200"] Lining head in pipe - Courtesy of Yorkshire water[/caption]

Benefits of lining

Compared to replacing the water mains, the relining option realises cost, carbon and programme savings:

• The average price for the lining option is £175/m whereas traditional methods, such as open cut, average £350/m.
• For carbon, the project at Stockton Lane saved 40% compared with traditional methods (as per the carbon calculator used by Yorkshire Water).
• Stockton Lane is a highly populated residential area and the relining method leads to reduced customer disruption/complaints. The contractor was able to reline 450-500m per week, as opposed to taking 3 weeks for the same distance of mains replacement using open cut methods.

Conclusions

The project has received a great deal of attention by a Designer Liner Group that is looking to create their own lining material, and Yorkshire Water and Morrison Water Services have facilitated site visits for the members of the group. There have been minimal customer complaints throughout the duration of the project and instead, there has been a lot positive feedback on social media outlining the great work that has been carried out on a daily basis.

The Stockton Lane Rehabilitation Project promotes the potential for future sustainable rejuvenation of clean water assets, and creates a method which reduces customer disruption whilst improving services that are provided by Yorkshire Water. Upon completion, Yorkshire Water will move onto the next phase in the series of three that are being delivered as part of the Year 4 AMP7 Improvement Project.

Ise Valley, Wellingborough, is home to the £1bn Stanton Cross housing development just off the B571 in the east of England. In late 2022, parts of the development were struck with leaks in the underground rising mains, causing disruption to many new homeowners during the Christmas period. In November 2022, Anglian Water was made aware of several leaks on each of the 700mm ductile iron rising mains from Ise Valley Terminal Pumping Station (TPS), which pumps flows of up to 1500 l/s. Both rising mains are required for normal operation of the pumping station and to convey the maximum flow, however, surveys showed that both mains had reached the end of their asset life due to both internal and external corrosion, and further leaks would occur if no action was taken.

Background

Once the team attended site, it became apparent that both the north and the south mains had leakage issues. Non-destructive testing confirmed external pitting and internal abrasion wearing in the upstream sections and an internal hydrogen sulphide (H2S) attack on the downstream section, which was determined to be the primary issue.

With two leaks occurring in close proximity, and previous leaks occurring over the last 10 years, there was a substantial risk of more. The @one Alliance was engaged on 1 December 2022 with the immediate priority being to design, install and commission an temporary above-ground bypass to mitigate the impact of any further potential leaks while the permanent solution was identified.

The Stanton Cross housing development was recently constructed over the area along the route of the rising mains, with houses as close to the asset as 4m in places and leaving no clear route to bypass the flows. As an added complication, some residents located close to the rising mains reported feeling vibrations from the mains;  the cause of which needed to be investigated.

[caption id="attachment_13372" align="alignnone" width="1200"] Temporary pipeline ready for assembly - Courtesy of @one Alliance[/caption]

Temporary solution

It was identified that the rising main leaving the building from the north could be isolated and cut into, to provide a temporary overland pipeline fed by the existing pumps, which would avoid the need for temporary pumping equipment over what would have been the Christmas period. Although the five pumps had recently been mechanically overhauled, the team found several electrical issues that required repairs. As such it was arranged for three temporary variable speed drives to be installed as a matter of urgency, to better manage pump performance and to help prevent further bursts before flows could be diverted.

Utilising contacts across the @one Alliance’s supply chain, specialist overpumping contractor Vanderkamp UK was contracted to provide a temporary bypass in short order. The teams decided on a 1m diameter pipe to give the equivalent flow of the existing twin 700mm diameter pipes to avoid reducing pump capacity.

Working around the clock to find a suitable solution, Vanderkamp UK, the @one Alliance and Anglian Water’s Water Recycling Networks (WRN), allowed for a quick design and installation of the bypass. The whole team aided the process from construction design management documentation to hydraulic design, temporary works, customer and PR, supply chain and enabling.

Ise Valley Sewer Rehabilitation: Supply chain - key participants

• Project delivery: @one Alliance
• Bypass pipework: Vanderkamp UK
• Cured in place relining: OnSite Central Ltd
• CIPP liner supply: IMPREG GmBH

[caption id="attachment_13369" align="alignnone" width="1200"] Road closures were necessary while installing the pipe bridges - Courtesy of @one Alliance[/caption]

Overpumping bypass pipeline installation

In order to build the overpumping solution as quickly as possible, the @one Alliance team collaborated with the Integrated Operational Solutions (IOS) Alliance that provided provisional enabling works such as electrical isolation of services, excavation of the point of connection and temporary ground drainage/pollution avoidance provisions. With the initial works complete, the @one Alliance took full control of the site and initiated the installation of the pipeline.

Work of this scale required a coordinated customer strategy which was designed and implemented by the @one Alliance Customer Team who notified all affected customers of the planned works and continued to provide updates throughout the various stages of work making sure customers were informed and suffered the least impact possible over a busy Christmas period.

To make the connection to the bypass pipework, all flows were diverted to the south main and twin 600mm tee pieces were installed in the north main within the terminal pumping station compound. This arrangement allowed the south main to remain in service if required over Christmas. The connection was completed on 9 December with installation of the 1m diameter pipework commencing the following day.

Due to the new housing development, it was not possible to follow the route of the existing mains and care had to be taken to ensure the bypass pipework would not interfere with a permanent solution or the ongoing operation of the pumping station. A route along Driver Way and Irthlingborough Road was selected which included several pipe bridges in order to allow unrestricted customer access. Emergency road closures were agreed with both the local property developer and North Northamptonshire Highways to safely install the pipework.

[caption id="attachment_13373" align="alignnone" width="1200"] Installing the temporary overpumping solution - Courtesy of @one Alliance[/caption]

The pipework installation was completed in just 10 days during an extreme cold snap which saw the @one Alliance and Vanderkamp UK operatives installing the overpumping pipeline in temperatures of -6°C. Nevertheless, the team worked two consecutive weekends to ensure the bypass was live and operational before Christmas. On 20 December 2022, the bypass was commissioned on time and to ensure there were no customer issues, inspections were carried out every day over the Christmas period.

Permanent solution

Testing and inspection of the mains showed that in the base of the pipe there were a series of what could be best described as wave patterns. The waves - the result of erosion of the pipe material - has been caused over many years by grit within the flow of sewerage. As the pipes rise steeply uphill the grit had settled at the base. Coupled with external and internal corrosion, susceptible areas of the ductile iron pipes have locally pin-holed, which had allowed leakage, and confirmed zero life span remaining in places.

Following the inspection and testing of the pipework, an accelerated Risk, Opportunity & Value sprint was held with all stakeholders to confirm the most suitable permanent solution. The team decided against the removal and replacement of the existing main due to the amount of time it would have taken to execute, additional disruption to customers and local traffic, and the small working space available to the team. It was then determined that the most effective solution was to use a structural liner.

The location of the trial holes, which had been used for examination and non-destructive testing of the mains, had been carefully selected as potential relining pits in the event this solution was to be used. This allowed for an accelerated programme to prepare for the relining works and a reduction in carbon and costs.

[caption id="attachment_13371" align="alignnone" width="1200"] Re-lining rig - Courtesy of @one Alliance[/caption] Rehabilitation of the existing mains using specialist pressure-rated cured in place pipe (CIPP) liners was selected. Framework supplier OnSite Central Ltd installed the liners using a combination of ultraviolet and water cure techniques to suit the challenging pipe conditions. Aware of the time constraints, OnSite Central Ltd worked with the project team to ensure the liners were delivered promptly from IMPREG GmBH in Germany, and that installation gangs were available to work extended shifts to ensure the challenging programme was delivered.

Once the relining was complete Vanderkamp UK  began dismantling the overpumping, all of which was removed by the end of May 2023. Pressure and vibration monitoring of the temporary bypass pipework identified a correlation between pressure spikes and vibrations. This resulted in a change to the pumping station regime and, along with the new variable speed drives and the liner acting as a barrier, resulted in a large reduction of vibrations felt along the route once flows had been returned to the rising mains. Post works vibration monitoring at a number of previously affected properties confirmed the vibration issues had been resolved.

Challenges

The team had to take into consideration a plethora of potential risks during the entire project lifecycle. From contaminated ground, congested buried services, extreme weather conditions, an construction challenges such as relining through 45° bends. The team had to sufficiently ensure a timely plan was in place, following many detailed impact plans created to overcome these issues to ensure efficiency in completion of the project, and reduce the disruption to customers over the festive period.

[caption id="attachment_13367" align="alignnone" width="1200"] Overpumping termination point - Courtesy of @one Alliance[/caption]

Customer liaison

One of the big challenges for this scheme was the disruption to the customers during the festive period, with the scheme attracting significant nationwide media attention over the duration of the works from national and local newspapers, BBC television (“Look East”), BBC radio (Jeremy Vine), and news and social media websites.

While this work went on, the @one Alliance Customer Team kept residents up to date with the team’s progress while helping manage expectations as to how long the work would take, and how long the temporary structure would be in place. Communications to the local residents were consistent throughout the project lifecycle (from 2/12/2022 to 24/4/2023), ensuring constant updates, programme times, and responses to queries were included at all stages.

Outcome

Anglian Water’s £2.8m spend and proactive response to this issue enabled the successful relining of the existing pipe. The relining solution, which will give the pipe an expected 100 years of extra service, has been in service for over a year with no issues.

York city centre, with its dense network of restaurants, takeaways, pubs, and other commercial establishments, has long faced significant challenges relating to fats, oils and grease (FOG). These businesses contribute substantial FOG loads to the sewage system, leading to issues such as blockages, odour problems, pollution incidents, and infrastructure strain. In 2023, Yorkshire Water (YW) embarked on a groundbreaking initiative to address these FOG challenges. The trial leveraged Cobra Hydro UK’s innovative Cobra Bio Block technology, aiming to enhance wastewater management efficiency, reduce environmental risks, and improve overall network performance. This case study explores the objectives, deployment, technology, outcomes, and industry implications of the trial, showcasing a significant step forward for sustainable utility practices.

Background & objectives

Before the trial, Yorkshire Water regularly encountered FOG discharge into the nearby River Ouse; presenting environmental hazards and regulatory compliance concerns.

The primary objective of the Cobra Bio Block trial was to mitigate FOG accumulation in York’s sewage network while exploring a cost-effective and environmentally friendly alternative to traditional FOG management methods. Specifically, the project sought to:

• Achieve a measurable reduction in FOG levels within the network.
• Eliminate pollution incidents caused by FOG discharge.
• Improve operational efficiency by minimising maintenance requirements and infrastructure stress.
• Assess the financial and environmental benefits of deploying Cobra Bio Block technology.

Project implementation

The trial commenced in September 2023 with the installation of Cobra Bio Blocks in over 40 key manholes across York city centre. The blocks were replaced every two months, ensuring consistent microbial and enzymatic activity. The final replacement occurred in August 2024, marking a full year of continuous operation.

YW provided a robust framework for monitoring the trial’s impact, utilising video footage, photographic evidence, and data collection to assess pre and post implementation conditions. These observations formed the basis for evaluating the effectiveness of the Bio Blocks.

[caption id="attachment_19284" align="alignnone" width="1200"] Bio Block - Courtesy of Cobra Hydro UK[/caption]

Cobra Bio Block technology

The Cobra Bio Block represents a pioneering approach to wastewater management. Designed for durability and simplicity, the Bio Block is a semi-submersible solution engineered to reduce FOG and odours in wastewater systems. Its unique features and mechanisms include:

• Innovative composition: The Bio Block consists of a slowly dissolving matrix enclosed within a durable, porous mesh sleeve. This design ensures gradual erosion and consistent release of active agents over time.
• Biological action: The block contains a blend of naturally occurring microbes and enzymes. As it dissolves, these microbes colonise surfaces within the sewage network, breaking down organic contaminants such as fats, oils, and grease.
• Ease of deployment: Suspended below the waterline in locations such as wet wells, pumping stations, or sewer lines, the Bio Block operates autonomously, requiring no electrical power, additional equipment, or extensive maintenance.
• Eco-friendly design: The non-toxic, environmentally safe composition ensures that the Bio Block poses no risk to aquatic ecosystems or surrounding environments.

Benefits of the Cobra Bio Block

The Cobra Bio Block offers several advantages over traditional FOG management methods:

1. Continuous action: Unlike periodic dosing solutions, the Bio Block provides a steady release of microbes and enzymes, maintaining consistent effectiveness even during heavy rainfall or washout events.
2. Odour and FOG reduction: By breaking down organic matter, the Bio Block significantly reduces unpleasant odours and FOG accumulation.
3. Low maintenance: Operating 24/7 without the need for active intervention, the Bio Block minimises the operational burden on utility providers.
4. Cost efficiency: The elimination of dosing equipment and associated infrastructure reduces both capital and operational expenditures.
5. Environmental safety: The non-toxic formulation supports sustainable wastewater management practices, aligning with environmental regulations and corporate responsibility goals.

Key findings from the trial

Yorkshire Water reported compelling results from the Cobra Bio Block trial, highlighting its effectiveness and transformative potential:

1. FOG reduction: The trial achieved a 90% reduction in FOG levels within the sewage network. This dramatic improvement alleviated blockages, enhanced flow capacity, and reduced infrastructure strain.
2. Elimination of pollution incidents: Prior to the trial, six FOG-related pollution incidents were recoded between 2019 and 2023. During the trial period, no major pollution incidents were reported, marking a significant milestone in environmental protection.
3. Improved network resilience: The absence of FOG-related flooding issues demonstrated the Bio Block’s role in enhancing system reliability and performance.
4. Financial impacts: Although detailed cost analyses were not provided, YW acknowledged the potential for substantial savings through reduced maintenance requirements, lower risk of fines, and improved regulatory compliance.
5. Stakeholder satisfaction: YW praised Cobra Hydro UK’s professionalism and the seamless execution of the trial, emphasising the collaborative effort’s success.

[caption id="attachment_19285" align="alignnone" width="1200"] Examples of the results after Bio Block dosing – Courtesy of Cobra Hydro UK[/caption]

Additional observations

The trial also uncovered secondary benefits that reinforced its value. Beyond the reduction of FOG and operational challenges, Yorkshire Water noted improvements in system cleanliness.

The microbial action facilitated by the Bio Blocks not only addresses fat and grease but also mitigated other organic contaminants. This broader impact on sewer line hygiene contributed to an overall reduction in maintenance costs and extended the lifecycle of infrastructure components. Additionally, the Bio Blocks’ low maintenance design allowed YW personnel to allocate resources more efficiently, focusing on proactive network management instead of reactive problem-solving.

The public’s perception of YW also benefited from the trial. By deploying environmentally friendly technology, the company demonstrated its commitment to sustainability and community well-being. This enhanced reputation is expected to yield long-term advantages in stakeholder trust and regulatory goodwill.

Implications for the utility industry

The success of the Cobra Bio Block trial offers valuable insights and opportunities for the utility sector:

1. Scalability: The simplicity and versatility of the Bio Block make it suitable for deployment across diverse wastewater systems, from urban centres to rural networks.
2. Sustainability: By prioritising eco-friendly technology, utility providers can align their operations with global sustainability goals, reducing environmental footprints and fostering community trust.
3. Cost management: The financial benefits of reduced maintenance, enhanced network performance, and regulatory compliance create a compelling case for wider adoption of Bio Block technology.
4. Collaborative innovation: The partnership between YW and Cobra Hydro UK underscores the importance of collaboration in driving industry advancements and solving complex challenges.

Testimonials

Kelly Burke, Network Protection Officer at Yorkshire Water, shared her perspective on the trial’s success:

“The trial of the dosing blocks in York has been very successful. The blocks have helped reduce incidents of fats, oils and grease causing blockages in the network and clogging up the pipes under the city to zero. In the last 12 months, we’ve had no pollution incidents linked to fats, oils and grease and no sewage escapes due to fat blockages.”

On 11 December 2024, the groundbreaking success of the product was featured on BBC Morning Live. During the segment, James Harrison, Head of Wastewater Asset Management at Yorkshire Water, highlighted its transformative impact on the utility’s sewer network:

“The thing that’s great about this product is that they’re easy to install, easy to replace. And they don’t just break down fat that is there, they can also prevent it’s built up as well, so it’s a really cost effective, practical, sustainable solution. The difference is incredibly noticeable if you look at the CCTV footage of the cameras down the sewer network, historically you would come back here to do an inspection and you’d see a coating round the pipe and it really starting to layer up, and the difference it has made is phenomenal.”

Clint Jackson, Business Development Director at Cobra Hydro UK, echoed these sentiments:

“Since we began this project in 2023, we have provided a cost-effective solution to reduce the fat, oil, and grease build-up within the sewers under the centre of York. We’re extremely pleased that our enzyme Bio Blocks have achieved the desired results.”

Conclusion

The Cobra Bio Block trial in York city centre represents a significant advancement in wastewater management. By addressing longstanding FOG challenges with an innovative, environmentally friendly solution, Yorkshire Water and Cobra Hydro UK demonstrated the power of technology and collaboration to achieve measurable improvements.

This case study serves as a model for the utility industry, illustrating how innovative solutions can enhance operational efficiency, protect the environment, and deliver tangible benefits to stakeholders. As the sector continues to navigate evolving challenges, the success of the Cobra Bio Block offers a roadmap for sustainable, effective wastewater management practices.