Inflow of stormwater and infiltration of groundwater into wastewater systems is a constant operational challenge for managers. Now, Håbo municipality in Sweden is tackling the challenge head-on with an innovative digital approach, says Adam Wood, chief product officer at water analytics company Infotiles.

Water utility managers in Håbo, a small municipality north-west of the Swedish capital, Stockholm, began conversations with InfoTiles in 2023, when they suspected infiltration of wastewater and inflow of groundwater into wastewater networks (I&I) was adding massive volumes requiring transport and treatment.

Managers wanted to investigate I&I further and needed tangible evidence to demonstrate the need for investment but were facing budgetary and operational constraints. Using control system data together with weather data and analysis of wastewater networks using in situ sensors, the collaboration sought to determine when and where I&I was occurring and decide on the appropriate response.

Gathering evidence
Inflow is stormwater that flows into wastewater pipes through faults such as holes, cracks, joint failures, and broken connections. Infiltration occurs when groundwater enters the wastewater network through faults in pipes, compounding the flow.

Magne Eide, chief operating officer at Infotiles, said, “InfoTiles set out to show Håbo municipality what the cost of not maintaining its wastewater network to prevent I&I would be, versus investing money now. Water managers wanted to understand what the maintenance opportunities were, so they could create a wider business case to be put forward for funding during the 2025 budget process.”

Servicing a population of around 18,700, Håbo’s water utility treats about 4 million m3 of wastewater per year. InfoTiles discovered that 18% of that water is incurred through I&I, leading to SEK13 million (roughly €1.3 million) of extra operating costs annually equivalent to almost SEK700 per inhabitant (roughly €61).

Energy use is a significant part of the additional treatment and transportation costs involved in processing I&I, which means reducing energy consumption represents a potential saving on operational expenditure when I&I is remedied. Extra energy consumption also represents a higher carbon footprint, so accurately identifying and preventing I&I can help utilities meet carbon commitments, including net zero targets.

Compounded flow
For many utilities and municipalities, I&I can account for an average of 20-50% of the annual flow in sewers, but during snow melt and wet autumns, this figure is much higher.

It is widely acknowledged that most I&I is caused by ageing infrastructure that requires maintenance or replacement, but some is also caused by erroneous connections such as building drainage and rooftops connected to the wrong pipes. When this water penetrates the wastewater network, it can overload the system, which is a particular risk during periods of heavy rain or storm events.

In the worst cases, it can lead to the release of untreated wastewater into the environment and pollution of rivers and seas. It also increases the risk of cross-contamination of drinking water, where polluted water from the environment enters through faults in clean water pipes.

Increases in the frequency and intensity of rainfall as a result of a changing climate is exacerbating the problem, making wastewater networks ever more vulnerable to failure and putting the environment at greater risk. If left untreated, pipeline integrity will only deteriorate over time, increasing the volume of ingress water to be treated.

For Håbo municipality, the overall goal of the collaboration with InfoTiles is to gain a better understanding of the causes of inflow and infiltration into sewerage networks and to understand the options for remediation and impact reduction. The municipality hopes it will help policymakers gain a deeper understanding of decision-making around I&I and show how collaboration and digital solutions can be used as a catalyst for positive change.

Accurate pin-pointing
Inflow and infiltration compounds wastewater operating costs as excess water must be pumped, treated and discharged.

The InfoTiles platform uses SCADA control system data together with data from the Swedish Meteorological Institute to analyse historical rainfall and the dry and wet weather behaviour of wastewater networks. For example, how and when water hits the network and how it affects pump heights.

Sensor devices placed at critical points in the network can collect data such as precipitation, problematic thresholds of rain volume, or seasonally varied sensitivities. That feeds into a central dashboard and these detailed measurements can then be analysed by water managers.

By using information from pump stations in real-time, the model calculates the total and excessive volume transported, allowing managers to see not only weather-related trends but also the resulting costs both in terms of treatment and power expenditure.

Once problem areas have been identified, the search area can be narrowed down using compact internet-of-things (IoT) devices within the same platform. Some pump stations have multiple inputs or long upstream pipeline networks. By selectively measuring different branches, it is possible to identify exactly where the water inflows and infiltrates or exclude areas that are not problematic.

Positive proof
Håbo operates 38 pumping stations, in a network where several smaller pumping stations feed larger stations before the wastewater is ultimately transported to treatment.

InfoTiles and Håbo municipality determined that the pumps closest to the treatment stations were receiving the largest net volume of water, meaning that the largest influx was occurring in the parts of the network directly relating to the largest pumps.

With this information, managers from Håbo went searching for damage in the identified areas and were able to quickly confirm the findings of the analysis. Significant breaches of the pipe were found upon visual inspection. In one location, drained surface water from nearby farmlands was penetrating wastewater pipes at high pressure, causing large and continuous volumes of I&I.

Sara Frid, water and wastewater strategist, Håbo Municipality, said, “The new insight into ingress water, such as volumes, likely sources, and the resulting costs really sparked an interest among our operators to go on the hunt for it.

“Within the first couple of weeks, we had found damages to our wastewater pipelines that we could repair to reduce volumes and save treatment costs.”

Now, water managers can not only use data to identify the areas with the highest need of maintenance and repairs but also see the results of their work in reduced volumes of inflow and infiltration.

Continually reducing the total volumes of I&I remains a high focus for Håbo municipality.

With the InfoTiles solution, they have been able to prove that investments in wastewater maintenance are not only an issue of environmental risk and cost, but in fact, the reduction in volumes will ultimately lead to reduced treatment costs in the long term.

Trials of a cutting-edge fats, oils and grease (FOG) Recovery Hub at Yorkshire Water’s wastewater treatment works in Hull are helping the utility improve environmental performance while lowering costs, says Chris Clemes, chief executive of engineering technology company EcoClarity.

Sewer blockages are a major concern in the UK, with an estimated 200,000 occurring annually, and FOG – fat, oil and grease – cited as the cause in around 75% of cases.

A build-up of FOG hinders the smooth operation of sewer systems and wastewater treatment works (WwTW), shortens the lifespan of critical assets and increases maintenance costs. This burden ultimately falls on water companies.

“As a water company, we suffer from thousands of preventable blockages each year from fats going down sewers. FOG blockages, or fatbergs impair the performance of wastewater assets which can cause sewer overflows, that can impact the environment,” explains Yorkshire Water’s waste services manager James Gudgeon.

“Water companies can spend a significant amount of money on staff and equipment costs to remove FOG from our sewers and send it to landfill – which also has an environmental impact. Additionally, network failures caused by FOG blockages carry the risk of costly environmental performance fines.”

As part of Yorkshire Water’s drive to increase efficiency within its operations, the water utility works alongside technology consultancy Isle to identify the latest technologies and innovations in clean and wastewater.

“In 2021, Isle suggested working with EcoClarity on our wastewater site, at a time we were looking to grow our imported waste business. The EcoClarity proposition gives us the ability to import different types of waste that we would not normally be able to treat.”

Yorkshire Water is the first UK water utility to install EcoClarity’s patented technology – located at its Hull wastewater treatment site. The modular, containerised EcoClarity system was introduced in February 2024 and will be used to treat FOG wastewater generated onsite during cleaning and maintenance procedures, as well as loads from waste management companies.

The process separates problematic FOG from wastewater and recovers a valuable energy resource for biodiesel production, while returning safe water to the environment. The operational model involves installing a network of FOG Recovery Hubs at wastewater treatment works and other sites suitable for liquid waste tankers to offload grease trap waste.

“We’re turning FOG waste into a valuable resource,” says Chris Febrey, EcoClarity’s operations manager. “By accurately measuring and verifying the composition of waste, we can verify reductions in greenhouse gas emissions for businesses and promote a circular economy.

“Our collaboration with Yorkshire Water highlights the importance of proper FOG management.”

The installation has a myriad of benefits for Yorkshire Water. Alongside the environmental and financial rewards of safely removing the FOG from the environment.

“Working in partnership is a significant commitment, but it was an easy decision once we looked at the holistic benefits of EcoClarity’s hubs,” says Gudgeon. “It brings us another avenue of engagement with the food industry and the FSEs [food service establishments] out there; it reduces the amount FOG going into sewers at source – preventing sewer blockages and protecting the environment, ultimately resulting in protecting our people not having to do high risk jobs.

“It also enables us to bring in new waste streams and new revenue streams into Yorkshire Water and ultimately that money is reinvested into the business and goes towards helping keep customer bills low – it is a true circular economy in action,” he adds.

FOG is a common byproduct of commercial kitchens and food processing facilities, but its disposal has long posed a challenge to the water sector. Currently, too much FOG enters the sewers and drains, causing blockages, which significantly impact the public, the environment, and are costly for water companies to clear.

The alternative is landfill disposal, which fails to capitalise on the value of FOG as a potential renewable fuel source. The patented EcoClarity system efficiently separates fat, oils and grease from wastewater, resulting in a 98% concentration of oil suitable for biodiesel production, which could ultimately be used to power the trucks transporting the FOG.

As EcoClarity sites are registered with Argent Energy’s Carbon Certification Scheme, the company can track the volume of greenhouse gas (GHG) emissions saved by the biodiesel produced from its FOG feedstock. This allows third-party companies, disposing of their waste in this way, to demonstrate their commitment to sustainability with transparency.

Long travel distances, slow offloading times, limited data on waste content, and a lack of transparency in pricing have historically led to frustration and a drain on profits for liquid waste operators. Thanks to EcoClarity’s highly efficient disposal opportunities, first at Argent Energy’s refinery in Stanlow, Cheshire, and now at Hull wastewater treatment works, travel distances for hauliers are minimised, along with fuel consumption.

EcoClarity’s FOG Recovery Hubs analyse the precise mass and FOG content of every load that comes in. As the FOG-rich waste goes through a mass meter, it is quantified and the data shared with the client – supporting their green credentials.

This also translates to quicker turnarounds for tankers, lower operating costs, and more time spent serving customers. Boasting up to a 87% reduction in greenhouse gases, biodiesel contributes to climate change mitigation and could be used to power tankers transporting wastewater – creating a tight circular economy of value.

“We are working with EcoClarity towards the potential nirvana of being able to harvest the FOG from our sewer network and turn it into biodiesel that fuels our vans. That’s the end goal,” added Gudgeon.

Further EcoClarity hubs are being planned by Yorkshire Water, with Knostrop wastewater treatment works in Leeds next on the list. Sites belonging to United Utilities and Southern Water, as well as two large entertainment venues in London and Cornwall, are also in the pipeline.

The Oxford Rivers Portal, a website and map that aims to help people understand the health of the Thames and its tributaries in Oxfordshire and make informed choices about safer river conditions, has been launched today (9 September) by environmental charities the Rivers Trust and Thames21 and research institute the UK Centre for Ecology & Hydrology (UKCEH).

The launch of the Oxford Rivers Portal follows increasing public concern over the state of England’s rivers, as well as a growth in interest in wild swimming and watersports.

On a single map, it brings together live raw sewage spill alerts, water quality measurements taken by the Environment Agency and citizen scientists, water levels, flood warnings, bacteria measurements at bathing water sites and sewage treatment rates* at both Oxfordshire’s designated bathing waters, Port Meadow in Oxford and Wallingford Beach. Users can zoom in and click on any of more than 2,000 locations to find out real-time information or data from the past three years.

Previously, these varied data sources were available on different websites and were difficult to access.

Claire Robertson, Oxford Rivers Project Officer at Thames21, said: “Water quality and the health of rivers must improve. The main sources of pollution are agriculture and the water industry, plus a growing threat from plastics and forever chemicals. As more people look to England’s rivers for recreation, we all need to up our game.

“We hope this portal makes it easier for people to decide whether they want to swim, or take out their canoe or paddleboard, on a certain day or not.

“River swimming is so good for you if you do it safely: don’t go into water you can’t swim against, don’t jump into water where you don’t know what’s underneath, and wash your hands after swimming.”

Dr Virginie Keller, an environmental modeler at UKCEH, added: “River pollution is now a major issue of concern for many people but it’s difficult to get clear, up-to-date information about water quality and conditions locally. Our portal is a ‘one-stop shop’, bringing together a variety of data in an accessible way.”

The development of the Oxford Rivers Portal is part of the European GOVAQUA project which aims to accelerate a transition towards sustainable and equitable water use by better water governance. It is funded by the European Union and UK Research and Innovation.

The team behind the portal says the data and information will enable users to gather evidence to understand the state of their local water courses and thus stimulate discussions between the public, regulators and water companies about policies and management relating to rivers and streams.

As designated bathing sites, Port Meadow in Oxford and Wallingford Beach are tested weekly for potentially harmful bacteria by the Environment Agency between mid-May and the end of September. Apart from one day at Wallingford, all the bacteria readings at these two sites have been below the level of concern this season.

Analysis of data from 2023 has found that five out of the seven local sewage treatment works for which data has been provided, show indications of illegal “early” spills of raw sewage.

Sewage treatment works must reach a minimum flow level (called “flow to full treatment”, or FFT) before they can legally discharge raw sewage to rivers and streams via storm overflows, to prevent it backing up in the system. The works are meant to be operating at this minimum level for between one and four hours before a raw sewage release is permitted.

However, on 183 occasions, treatment works had not met this minimum flow rate in the past 24 hours before a raw sewage discharge occurred. Oxford sewage treatment works had 77 separate “early spills” totalling 1,839 hours, Appleford works had 89 spills totalling 1,692 hours, and Stanton Harcourt works had seven early spills totalling 1,322 hours.

*Sewage treatment rates show the rate of sewage treatment at a sewage treatment plant in litres per second. Users of the portal can use this data to find out if a sewage treatment plant is operating at full capacity or operating at low capacity.

The Environment Agency’s director of water, Helen Wakeham, has discussed plans to increase scrutiny of water companies in England and Wales in a new water sector podcast.

Targeted recruitment campaigns, more site inspections and enhanced digital systems will drive better performance from the industry, Wakeham told the WiseOnWater Podcast: Conversations in Flow, from media specialist WiseOnWater and technology company Xylem UK & Ireland.

“We’ve an awful lot more investment in water regulation. We consulted earlier this year on increasing our charges for water quality discharges and we’ll use that to increase our scrutiny of water companies,” Wakeham told podcast host Natasha Wiseman.

Site inspections will increase to more than 10,000, to be supported by new recruits, including “boots on the ground” and data analysts, Wakeham said. “It’s a really exciting time. There are a lot of people around with loads of experience. It’s brilliant for those people to be joined by a new cohort with new ideas.

“Data can help us. When I started my career in 1990 it really was whack-a-mole. These days we can be a lot cleverer than that. We’ll be able to focus our effort on where we know the problems are. We’ll be able to visit the places that matter to people.”

Reflecting on the public’s heightened awareness of water quality, Wakeham said: “I think what started off as perhaps quite a narrow debate about storm overflows has brought the value of water to people’s attention. While some of those conversations are hard, it’s brilliant to have water very much more in the public consciousness. I think we’ve realised how central it is for all of us.”

The WiseOnWater podcast, which launched on 9 September 2024, is a monthly deep dive into the ever-changing landscape of the UK water sector.

Joining Wakeham on episode one is Margaret Read, director of policy at the National Infrastructure Commission, who explores the proposed £96 billion 2025-30 AMP8 investment.

She said: “We’ve got a lot of different issues to solve in the water sector. The first one which we’ve looked at in detail is the water supply question. We haven’t built any reservoirs in the UK for over 30 years and we’re facing a big gap between supply and demand.

“Secondly, we’ve got problems, as everybody knows, with water pollution and that requires a big investment to resolve. Then thirdly, we also need to maintain our existing assets. So, it does sound like a big amount of money, but we will need it – we also need to be realistic about what can be delivered over that period.”

Read urged regulators and government to “speak with one voice” and “be really clear with the public that there is a need for this new infrastructure and that they will have to pay for it”.
“That takes some political courage,” she added, “but it’s really important.”

For project delivery, Read said water companies need to collaborate more closely with each other and the supply chain to “solve these problems once rather than many times”.

Pollution reduction, nature-based solutions, smart metering, leakage, drought resilience and bill increases were among other conversation topics in the 30-minute podcast episode.

Episode two focuses on skills, recruitment and retention with guests Peter Simpson, chief executive of Anglian Water and Sarah McMath, chief executive of MOSL. Future episodes feature Wessex Water chief executive Colin Skellett and the managing director of Xylem UK & Ireland, Ian Thompson.

Wiseman, founder of WiseOnWater and non-profit news platform Make Water Famous, said: “In each episode of the WiseOnWater podcast we’ll bring together the brightest minds in water, from industry leaders and policymakers to engineers, communicators and researchers. These are the people tackling the pressing challenges of today and ensuring the future availability of our most precious resource.

“We are especially excited to be supported by Xylem UK & Ireland, who have a deep understanding of the needs of this sector. It has never been more important for organisations in water to explore new collaborative communications initiatives if we are to ensure a sustainable water future for the UK and beyond.”

Andrew Welsh, water utility sales director at Xylem, said: “At Xylem we believe that meaningful conversations are the cornerstone of progress in the water sector. Partnering with WiseOnWater to launch this podcast allows us to bring critical discussions to the forefront, driving awareness and collaboration on the most pressing water challenges.

“By connecting industry leaders, policymakers, and innovators, we aim to not only highlight the issues but also inspire actionable solutions that will shape a sustainable future for the UK’s water infrastructure.”

Episode one of the WiseOnWater podcast is available now on Spotify.

International research team say they have identified more than 120 organic micropollutants and investigated their role in damaging aquatic organisms

Tonnes of dead fish, mussels and snails were seen floating on the River Oder (Germany) in early August 2022. It soon became clear what was causing the environmental disaster in the German-Polish border river: a mixture of excessive salinity, high water temperatures, low water levels and excessive inputs of nutrients and wastewater triggered a bloom of the brackish water algae Prymnesium parvum, whose algal toxin prymnesin has a lethal effect on organisms. A team of scientists coordinated by the Helmholtz Centre for Environmental Research (UFZ) collected and analysed water samples at the time. The result, published in Nature Water today (6 September), appeared to show that high concentrations of organic micropollutants exacerbated the lethal effects of prymnesin.

Summer 2022’s environmental disaster led to the death of up to 60 per cent of fish biomass and up to 85 per cent of mussel and snail biomass in the River Oder. In August 2022, the UFZ set up an interdisciplinary ad hoc working group together with researchers from the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), the University of Veterinary Medicine, Vienna (Vetmeduni) and the University of Birmingham. They took water samples at five locations along the Oder, extracted poisoned fish and analysed and evaluated the samples. “The aim of the study was to find out which micropollutants are in the Oder, how they affect aquatic organisms in the river and what threat the cocktail of algal toxins and micropollutants could pose to humans,” says Prof Dr Beate Escher, lead author and environmental toxicologist at the UFZ.

As the researchers now explain in the scientific journal Nature Water, they were able to detect more than 120 organic micropollutants in the water samples. The highest concentrations of chemical substances were found for the flame retardant tris(1-chloro-2-propyl)phosphate, the polymer additive hexamethoxymethylmelamine and the corrosion inhibitor 1H-benzotriazole. Most of the pollutants detected were presumably discharged into the Oder from sewage treatment plants, but their concentrations were low. However, the scientific team also found pollutants such as 2,4-dichlorophenol, which were probably discharged from industry, as well as pesticides and their degradation products, such as chlorotoluron, which were discharged directly into the water from agricultural land. “The concentrations of these chemicals are not unusually high, but are typical for European rivers”, says Beate Escher. “They did not lead to fish mortality, but together with the algal toxins they can lead to additional stress for aquatic organisms.”

The researchers used the risk quotient RQ to analyse the extent of this stress and thus the risk of the detected pollutants for aquatic organisms. The RQ is defined as the ratio between the measured concentration of a pollutant and its predicted no effect concentration (PNEC). If the RQ exceeds the value of 1, the pollutant can affect aquatic life. The researchers added up the RQs of the detected chemicals and thus obtained mixture risk quotients (RQmix) of between 16 and 22 at the sampling sites. “All RQmix values significantly exceeded the threshold value of 1, which indicates a potential risk to aquatic organisms from pollutants,” says co-author and water chemist Dr Stephanie Spahr from IGB. Only 30 organic micropollutants were included in the model, although thousands of organic chemicals are probably present in the river. The chemical cocktails extracted from the water samples also showed clear effects in laboratory experiments with algae, water fleas and zebrafish embryos, which are considered common models for aquatic organisms.

The researchers investigated how these pollutants and the prymnesins found in the Oder interact as mixtures in water extracts using neurotoxic effects on human nerve cells in vitro. “This test, which is commonly used in bioanalysis and water quality assessment, does not aim to assess the risk to human health, but rather to identify the mixture effects of neurotoxic chemicals,” says Beate Escher. Assistant Professor Dr Elisabeth Varga, a food and environmental analyst at VetMedUni Vienna, provided an algal toxin standard that is very similar to the prymnesins identified in the Oder. The in vitro assays are carried out at the UFZ in automated high-throughput screening in the modern CITEPro[SH1] technology platform in very small volumes. “It was therefore possible to test this prymnesin standard and other detected micropollutants as well as the water extracts directly,” says Beate Escher. Even at very low concentrations in the nanomolar range, prymnesins shortened the outgrowths of nerve cells that are responsible for signal transmission and killed the cells.

In addition, many organic micropollutants quantified in the water extracts were analysed: several substances were neurotoxic, but at significantly higher doses. “Through mixture modelling and comparisons of the neurotoxicity measured in the extracts, we were able to show that prymnesins dominate the neurotoxic effect. However, the micropollutants we detected also contributed to this,” says Elisabeth Varga. However, the effects of pollution on aquatic organisms in rivers such as the Oder could ultimately be much greater. “The prymnesins have a very high proportion of the cocktail effects, which are exacerbated by micropollutants. This puts even more pressure on the entire ecosystem of the Oder, which is already under great stress,” says Beate Escher. And Prof Dr Luisa Orsini, co-author and Professor of Evolutionary Systems Biology and Environmental Omics at the University of Birmingham, adds: “The warmer temperatures and extreme weather events caused by climate change can make such toxic algal blooms an even greater risk for inland and marine waters and the population.”

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Regulations for hydrostatic pressure testing have taken a significant step forward with the release of Water UK’s Water Industry Standard for hydrostatic pressure testing of PE pipes, a move that will ensure the safety and reliability of the process, says Tony Kitchen of AHS Pipeline Innovation.

Water companies and contractors are adjusting to the requirements of the new Water Industry Standard 4-01-03, released in March 2024, which outlines the required standards for the hydrostatic pressure testing of polyethylene (PE) and polyethylene barrier pipes. The standard replaces previous guidelines from Information Guidance Notice 4-01-03.

The transition from an Industry Guidance Notice (IGN) to a Water Industry Standard (WIS) marks a shift towards more stringent and enforceable standards that aim to improve the safety and effectiveness of the pressure testing process.

WIS 4-01-03 specifies detailed procedures for pressure testing below-ground water supply pipelines and sewer rising mains comprised of PE and PE barrier pipes. It includes guidelines for testing entire systems as well as replacement sections and service connections.

The specifications emphasise the importance of considering the viscoelastic properties of PE, which exhibits what is known as creep behaviour – deformation that occurs when subjected to pressure over time.

Understanding the difference
It is important to understand the distinctions between WIS and IGN:

● An Information Guidance Notice serves as a set of recommendations or guidelines that offer advice on best practice but does not mandate specific actions or procedures.
● A Water Industry Standard is a more formal document that sets out mandatory requirements for products, materials or operational procedures. WIS documents are intended to ensure uniformity and compliance across the water industry, leading to more standardised and reliable outcomes.

Improving safety
The new WIS is designed to improve both the accuracy and safety of pressure testing which means there is now a zero-tolerance policy on pre-pressurisation. Key points are:

● The pipe must be at ambient pressure prior to testing
● If a test has failed, the operator must leave the pipe for four times the length of the ramp-up time before reattempting the test
● The operators must wait for two to three hours between filling and pressurising the pipeline. This takes into consideration the effects of thermal conditioning and allows the temperature of the pipe to stabilise once it has been filled.
● The allowable air content has now been reduced from 8 to 4 per cent
● The air content must also be accurately calculated during the ‘ramp-up’ stage as the pipeline is brought to system test pressure (STP). This means that the test can be immediately abandoned if it is over the acceptable limit.

What WIS means for contractors
There is no question that the new standard represents a significant step towards leak-free networks, but the new requirements potentially impose a greater burden on contractors. The stringent rules around correct preparation prior to testing, including pre-pressurisation, thermal conditioning, and calculating air content prior to starting the test, making it crucial to get the test right first time, to prevent wasting time and resources in retesting.

A reduction in the allowable air content means less margin for error, which highlights, from a compliance and cost perspective, the importance of contractors carefully managing their own and subcontracted pipeline pressure testing.

Due to the increasing complexity of hydrostatic pressure testing and varying levels of expertise among technicians and operators, some pressure testing providers may not meet the standards outlined in the WIS and could lack the knowledge or skills to correctly prepare the pipe for testing.

Contractors must ensure that all pressure testing activity is fully compliant with the new WIS specifications. Substandard testing potentially creates dangerous situations, with risk to life and limb, if air is not properly removed from the pipeline.

It is crucial for contractors to select subcontractors with proven compliance to ensure the safety and reliability of their projects if they are to maintain both contractual obligations and a good reputation in the industry.

Proven expertise
AHS Pipeline Innovation is recognised as an industry leader in hydrostatic pressure testing with over 20 years of experience and almost 50,000 tests completed. The proven expertise of AHS allowed the company to play a key role in the development of the new WIS as part of a multidisciplinary panel which included pipe manufacturers, water company representatives and trade organisations.

Careful consideration was given to onsite implementation of the new requirements, and how contractors can be supported in meeting the standard.

Pressure testing services at AHS are already fully compliant with WIS 4-01-03 and incorporate the latest technology and real-time assistance from the company’s in-house analyst teams to give contractors unrivalled support throughout the testing process, ensuring that testing is right first-time.

AHS is equipped to guide and support teams in adopting these new standards so that their pipeline operations meet the necessary requirements. Should water companies and contractors be unsure about how WIS 4-01-03 affects their operations, or require support to ensure compliance, AHS is available to provide the knowledge and tools necessary to navigate this transition smoothly and effectively.

WIS 4-01-03 not only mandates stricter controls over variables like air content, ambient pressure and temperature, it also effectively identifies and removes any activities undertaken onsite that can affect test performance. Importantly, it reintroduces rules that had been relaxed in previous guidance, restoring rigorous standards that are essential for maintaining the integrity of water systems and creating more defined regulatory expectations.

In addition, pressure tests carried out in accordance with the WIS are measured using sophisticated algorithms that deliver definitive test outcomes, ensuring clarity and reliability.

At a time when the water sector is experiencing reputational challenges, WIS 4-01-03 represents an opportunity for water companies and contractors to get it right from the start. By carefully navigating these changes, and ensuring that every test not only meets but exceeds the latest standards for safety and efficiency, they can mitigate risk to the public and their own teams altogether.

Urban locations worldwide are struggling to manage stormwater drainage, in the face of extreme weather. The opportunity appears vast, for those who can help solve the problem, as Envirotec writes.

“Managing too much water” is the biggest challenge facing UK water utilities today, according to Bluetech Research director Paul O’ Callaghan, during his opening address at the group’s flagship event in Edinburgh in June.¹ It’s a problem where the public is becoming increasingly impatient, and the regulator is putting on pressure. It’s also a pressure point where the coping costs are astronomically high, and he cited estimates that the cost of flooding in the US is US$400 billion.

It was one of “eight areas for opportunity” in water technology outlined in his talk, with other big ones including “water reuse”. That’s the problem with water, you either have too much or too little of the stuff.

When it comes to avoiding inundation, well-designed infrastructure is obviously important, but the sheer quantity of rainfall that can now fall without warning in many places clearly complicates things.

Climate change is expected to bring a more variable water cycle,² with weather conditions veering towards extremes of dryness and wetness. And this seems to be a key factor in the increasing difficulties being faced worldwide, when it comes to managing the hydraulic capacity of sewer and stormwater networks. In New York, for example, where CSO pollution in the harbour had caused public disquiet 15 years ago, a problem that was subsequently resolved, the issue of sewer security and stormwater management seems to be once more climbing the agenda, following a series of unprecedented storms.³

Senescent structures
Sewer security is a growing problem worldwide, although it seems especially acute in the UK, attributable in part to the proportion of the nation’s sewer network that is combined with stormwater, in contrast to the US, for example, where sewer and stormwater networks seem to be mostly separate. While overflows can occur with both combined and separate sewage networks, the CSOs are obviously more vulnerable to extreme weather. They are also more often associated with older cities.

One country with more of them than the UK is Italy. However, a more likely flashpoint of public disapproval seems to be wastewater treatment, with only a little over half of the country’s wastewater currently being treated to EU standards.⁴

Globally, the regulation is becoming tighter and more specific, which is driving the urgency of tackling the problem.

In the UK this also includes mandatory levels of investment, with Defra’s National Storm Overflow Plan, for example, having earmarked more than £10 billion for storm overflow improvements – triple the previous level of investment.

But there’s a potentially big price tag. For example, completely removing and replacing CSOs, would require an entirely new sewer network costing up to £600 billion⁴ and widespread, disruptive roadworks over many decades, according to a recent white paper on sewer security published by Global Water Intelligence in collaboration with Grundfos. So, there is a need to target fixes and solutions, to achieve a balance between improved sewer security outcomes and economics (and customer bills).⁵

Defra’s recent (2022) plan requires utilities to make improvements in sewage release from combined systems, and sets out specific requirements, although some of these appear ambiguous or difficult to police. For example, water companies will only be allowed to discharge from storm overflows where they can demonstrate there is no local adverse ecological impact. In a recent book,⁶ Dr Julian Doberski wonders whether such a thing is even possible.

In any case, the pace and scope of change hasn’t been sufficient to satisfy many environmental pressure groups.

When it comes to the way the issue is being perceived by the wider world, problems of under-ambition and even neglect seem to take a far more prominent place, and this certainly ratchets up the pressure on utilities to find solutions quickly.

Ofwat’s recent investigation into water companies’ conduct highlights systemic problems and a failure to invest in water infrastructure, with fines of £168 million having been handed out to Thames Water, Yorkshire Water, and Northumbrian Water in July.

As the CIWM’s Policy Director Alastair Chisholm commented in August: “Historic abuses by water companies and failures by regulators to keep them in check mean there is now a rearguard action to remedy the damage,billed as ‘record investment’. Whilst this is necessary, it cannot come without wide and deep, meaningful change.”

He called for “considerable investment over the long-term, allied with far stronger, yet outcomes-focused regulation that prioritises the necessary actions, catchment-by-catchment, to begin the process of recovering the health and resilience of our waters.”⁷

A considerably strengthened environmental regulator was another necessary ingredient suggested by Chisholm and others.

But the question of what constitutes success in achieving “sewer security” seems to have more complexity than a straightforward focus on “number of spills”, and there seems to be some distance still to travel to properly understand it, and to find solutions.

Sizing up the problem
One aspect of the question of “how to get there” can be addressed by a combination of short-term and long-term interventions. For example, short-term fixes include using disinfection at CSOs, or digital tools to better understand and pre-empt outfalls, while longer-term ones such as building new infrastructure are also getting underway.⁸

At a discussion session on “Sewer Security” at BlueTech Forum in June, delegates shared views on the various pieces of the puzzle. Chaired by Phil Tomlinson of water technology firm Grundfos, he opened the session with a nod to the fact that maybe technology alone can’t solve the problem, that it’s not just about “cool stuff”.

One delegate indicated problems with the way the issue is being perceived. There has been some fair criticism of the regulatory environment, and a lot of opprobrium focused on English utilities. It’s not a new problem, although it has become more acute given the intense rainfall, and the “monsoon-style events” of recent years. What’s not being picked up enough is that a lot of the work being done on the ground by utilities has been good, he said.

“I don’t think we understand the problem properly,” said one participant.

A first line-of defence in this respect would seem to be monitoring CSOs. Nearly all of these are monitored in England, but there are outstanding issues regarding the usefulness of this activity, suggested participants in the discussion. For example, how do we access, utilise, store and act on this data? Also, how might you get the data quickly enough to act on it?

Digital tools are one way to identify pain-points and high-risk areas in the network, offering a way to prioritize remedial work and reduce costs, through the use of IoT sensors and analytics. The GWI/Grundfos white paper gives the example of Grand Rapids (Michigan, US) where the city had already completed a sewer separation project in 2015, but needed a better understanding of inflow and filtration in the network, to meet a regulatory requirement (which mandated that there be zero overflow events of any kind, except during a wet weather event exceeding a 24-hour, 25-year storm). The use of digital tools allowed inflow and filtration issues to be solved for $30-50 million, compared to initial estimates of $1 billion.⁹

Maximizing hydraulic capacity
One direction of travel seems to be the use of digital technology to make the most of the capacity available in the network, or to allow the use of additional infrastructure features, which might include canals, as is the case with Glasgow’s Smart Canal system (see side panel “Smart canals”, at the end of this article).¹⁰

Presenting at the Bluetech event, Dr Sonja Ostojin, Head of Innovation with Environmental Monitoring Solutions (EMS), summarized the UK’s storm overflow challenge. Solutions are needed quickly, she said, and the old-style grey ones, like building a massive tank, “won’t work this time”.

Her own group’s Centaur monitoring and control system uses AI to respond to storm water in the system “in real-time”. Gates are used to control the flow through the system, which means capacity within the pipe network can be used to store some of it, preventing spills from storm overflows.

Centaur has been deployed in a few locations since 2017, and is being demonstrated in the EU’s REWAISE project, which aims to address hydraulic capacity issues in wastewater networks. Southern Water has trialled the approach in Kent and the Isle of Wight, and the group’s Keith Herbert has said “it has the potential to be a gamechanger as it is more cost-effective and less carbon heavy than other methods like building storm tanks.”¹¹

Grey infrastructure initiatives like London’s Super Sewer have been the principal means of increasing the ability of sewers to handle increased flows. However, green infrastructure can prevent stormwater from entering the sewer system in the first place, and a growing shift towards this kind of solution seemed to be spotlighted at the BlueTech event.

Sponge cities
The concept of the “sponge city” involves a combination of these different forms of infrastructure, or so suggested the presentation given by Professor Kongjian Yu, credited as the pioneer of China’s sponge city movement, and the founder of Turenscape, a company specialising in this kind of urban infrastructure.

Much like a sponge, a sponge city can absorb stormwater, and then release it for water supply when needed.

Yu spoke about how the environment of cities can be transformed to retain water and create stunning urban landscapes. Grey infrastructure is still a key component in these sponge cities, but the concept implies a noticeable shift to blue and green infrastructure, with improvements in biodiversity and water services.

Scale and ambition certainly seem to underpin the concept, and in Shanghai it has been credited with delivering a multi-billion-dollar cost saving over traditional grey infrastructure.¹²

Since China’s national Sponge City Programme began in 2014, a first group of 20 cities has been targeted for development (following a June 2021 announcement), each receiving around $109-172 million from the central government. The programme intends that 80% of urban areas should meet the standard of retaining 70% of stormwater in situ by 2030, requiring an estimated investment of US$ 1 trillion.¹³

One apparent criticism of the concept, or at least, the insistence that it is not a panacea, comes from Professor Guangtao Fu of the University of Exeter, in a 2022 paper,¹⁴ which points out that a sponge city programme did not prevent the flooding in Zhengzhou in July 2021, when a year’s worth of rainfall occurred within 24 hours, causing a disaster that claimed 292 lives, and initiated a chain of failures including a loss of parts of the electricity network and subsequent paralysis of card and mobile payments.

The paper recommended measures such as resilience mapping, to identify acute pain points in the urban landscape. Its lessons seem to apply specifically to the Chinese situation, where gated communities are the norm, and includes building-level measures such as elevating the height at which electrical systems are positioned, and the use of water-proof materials when building walls to a level higher than the likely flood depth identified by resilience assessments.

Filtering on the fly
Green infrastructure techniques – like wetlands, permeable pavements, and green roofs – can slow down the flow of rainwater, ensuring its more gradual release into rivers and water features, and this seems a huge element of the sponge city concept. Some natural filtration will also occur, removing pollutants from rainwater.

Permeable pavements mean that rainwater can infiltrate the ground, reducing surface runoff and replenishing groundwater. They can help reduce flood risk while also serving to diminish heat island effects.

Similarly, urban wetlands can provide benefits, including reducing the flood risk to homes, promoting biodiversity, boosting air quality, and providing a recreational space.

In June, environmental charity Thames21 said it was working with partners and volunteers to make London a sponge city, through creating wetlands, planting trees and supporting sustainable drainage. One reported success is its ‘Rewilding the Rom’ project in Dagenham, in which a wetland has been developed to connect the River Rom to its floodplain, providing a better environment for wildlife.¹⁵

The CPRE’s Anna Taylor supported the call, highlighting “the urgent need for more rain gardens across the capital to reduce road-run off, ease the pressure on storm water drains, and help to reduce the risk of sewage overflow into our rivers.”

She added: “Sustainable urban drainage assessments should be bog standard when roadworks and streetscapes are being updated.”

Elsewhere in the UK, the Mansfield Sustainable Flood Resilience project was one of the projects which seemed to generate discussion at the BlueTech Forum event. It involves the installation of hundreds of sustainable drainage systems (SuDS) throughout the town, making it seemingly “the largest retrofit scheme of its kind in the UK”. This includes blue-green infrastructure intended to slow and store water, such as detention basins, bioswales, rain gardens, tree pits and permeable paving.

The project follows Severn Trent’s identification of the town as one of the most at-risk communities in Nottinghamshire, and it is expected to receive £76 million funding from the utility, providing additional storage capacity for surface water, and creating resilience in the network.

Technology solutions and infrastructure clearly seem to be important, but also just one part of the puzzle, and the Sewer Security discussion during Bluetech attached importance to many other factors, including: improving our understanding of the problem, and also communicating successfully about what needs to be done.

Those close to the problem seem to agree that there needs to be collaboration between a larger number of stakeholders. This could allow the creation of “more supportive and outcome-based regulation”, as the GWI/Grundfos white paper puts it. The document calls for a shift in the narrative of regulation, “away from number of spills and towards regulating overall water quality.

[ SIDE PANEL – Smart Canals ]

With automation, real-time control and weather forecasting, it is possible to make room for stormwater storage in the network, or other available infrastructure, pre-empting extreme weather events before they happen. This can help avoid the costs and carbon costs of additional grey infrastructure.

The North Glasgow Integrated Water Management System (NGIWMS), which opened in 2022, makes use of the Forth & Clyde Canal, receiving the excess stormwater runoff from new regeneration and development areas, then returning the canal to its normal level after the storm.

It was designed to ensure no flooding occurred elsewhere, and would not impact navigation the canal or waste water (which would impact abstraction license conditions).

The canal opened in 1790, providing a sea-to-sea navigation (the world’s first) between Glasgow and Edinburgh.

It uses a real-time hydraulic model in ICMLive software (essentially a digital twin of the canal), which receives data about rain forecasts and canal status from sensors on a SCADA network, predicting the additional storage that will be required, in advance of a rainfall, and automatically lowering canal water levels via actuated sluice gates.

One challenging aspect is the fact that weather forecasts decrease in accuracy when made ahead of time, while the drawdown of the canal itself takes a long time, around 18-hours to drawdown 100mm if all discharge sluices are fully open.

The model is continuously updated as new surface water connections are added with the appearance of new developments in the locality.

The system was designed and developed by AECOM in conjunction with Scottish Canals, Glasgow City Council and Scottish Water.

Notes
[1] BlueTech Forum 2024. Assembly Rooms, Edinburgh. 3-4 June 2024.
[2] “Sewer Security: Enabling resilient water infrastructure” white paper, Global Water Intelligence in collaboration with Grundfos, May 2024. See https://my.globalwaterintel-insights.com/l/2DC/SewerSecurity. [3] ibid [4] ibid [5] ibid [6] The Science of Sewage: What happens when we flush? By Julian Doberski. A Pimpernel Press book for Gemini Adult Books Ltd. Published in 2024. [7] Email, “CIWEM response to breaking news: Proposed Ofwat fines for water companies”, received on 6 August 2024.[8] “Sewer Security: Enabling resilient water infrastructure” white paper, Global Water Intelligence in collaboration with Grundfos, May 2024. See https://my.globalwaterintel-insights.com/l/2DC/SewerSecurity. [9] ibid [10] Glasgow’s Smart Canal (2022). Published: June 12, 2022. See https://waterprojectsonline.com/case-studies/smart-canal-2022/ [11] “Cutting edge technology to be piloted to help reduce storm overflows and flooding in Kent and the Isle of Wight”, Southern Water website. See https://www.southernwater.co.uk/latest-news/cutting-edge-technology-to-be-piloted-to-help-reduce-storm-overflows-and-flooding-in-kent-and-the-isle-of-wight/. [12] Press release. “Water industry needs common purpose, says Mark Fletcher”, from Wise On Water, 17 January 2022. [13] “Are sponge cities the solution to China’s growing urban flooding problems?”, by Guangtao Fu. In WIREs Water, October 2022. [14] ibid [15] “Call to make London a sponge city”. Press release, Thames21, June 2024.

Sewage pollution in surface waters in the UK and Ireland is one of the most high-profile environmental issues in the country. Water industry research organisation UKWIR says it is leading a raft of innovative sewerage projects designed to transform the way water companies manage this issue in the coming five-year Asset Management Plan period for England and Wales – AMP8, which starts on 1 April 2025.

“UKWIR’s research programme aims to create a future where sewerage management is not just an essential service, but a key contributor towards a sustainable and healthy environment,” said Jenni Hughes, UKWIR strategic programme manager.

“Previously, UKWIR research has focused on getting a deeper understanding of the networks, because we need to understand what’s happening in the existing network before we can make meaningful, long-term improvements.

“Now our focus shifts to the future, with societal needs, environmental protection and resilient infrastructure at the centre. The latest wave of research offers water companies the tools and knowledge they need to navigate the ongoing challenges of sewage management into the next asset management period and beyond.”

Protecting rivers and seas
The impact of sewage and stormwater discharge, agricultural runoff, and urban pollution on river ecosystems in the UK and Ireland is a key area of research for UKWIR.

Dr Nick Mills is UKWIR’s programme lead on the organisation’s Big Question 6: How do we achieve sustainable and resilient sewerage and drainage by 2050? He is also director of environment & innovation at Southern Water.

Mills says, “To optimise the benefits for both people and nature, we need a data-driven river strategy that comprehensively analyses threats to river health. This approach should hold all sectors accountable, while simultaneously empowering them to identify solutions for building and maintaining healthy rivers.

“There is a lot of focus on storm overflows in the media and from the general public. They are a legacy asset that the sector is attempting to phase out through a combination of nature-based and sustainable drainage systems, and data-driven engineering approaches.

“More widely, reducing storm overflows requires urgent, collaborative action from water companies, councils, property owners and the public,” added Mills.

Beating blockages
Sewer blockages are a major concern in the UK, with an estimated 200,000 occurring annually, and FOG – fats, oils and grease – cited as the cause in around 75% of cases. A build-up of FOG hinders the smooth operation of sewer systems and wastewater treatment works (WwTWs), shortens the lifespan of critical assets and increases maintenance costs.

This burden ultimately falls on water companies, which may be forced to raise prices for customers. Additionally, FOG blockages can cause sewer overflows, creating a public health hazard and impacting the environment.

UKWIR projects aiming to tackle this include:

• Understanding the scale and impact of privately owned drains and sewers on sewer capacity
• FOG charging – should food service wastewater charges reflect FOG content?
• Modelling sewer inlet capacity restrictions
• Treatment options for storm overflows

Nature as a stakeholder
Protecting and enhancing waters, and the wildlife and communities they support requires a combination of grey and green solutions. For water companies looking to create greater social value, nature-based solutions (NbS) such as sustainable drainage systems (SuDS) can offer a powerful and cost-effective approach.

However, there is currently limited sector-wide data on the benefits, reliability and cost-effectiveness, compared to traditional engineered and technological alternatives.To address this issue, UKWIR currently has a research project aimed at improving the understanding of the whole-life cost, carbon footprint and delivery of retrofit SuDS.

Data and insights
Water companies in the UK are being urged to be more transparent with the public about sewage spill data by the information commissioner.

The use of data-driven methods, including artificial intelligence and predictive analytics, is a promising approach to proactively identify and address blockages in sewer systems, ultimately improving environmental protection, public health and compliance with regulations.

Recent UKWIR projects include:
· Modelling sewer inlet capacity restrictions
· Quantifying, managing and communicating the differences in storm overflow spill data between event duration modelling (EDM) outputs and hydraulic model prediction

Working with customers
Customer behaviour can also play a significant role in reducing the amount of sewage entering watercourses in the UK.

Customer-caused blockages in sewers are a major issue in the UK. Every year in England and Wales, water companies spend millions of pounds dealing with over 300,000 blockages – thousands of which see people’s homes and belongings ruined by sewer flooding.

A recently published UKWIR project – Learning and recommendations from customer behaviour campaigns on blockage reduction – highlights the need for effective customer campaigns to reduce blockages, and emphasises the importance of tailored campaigns, a unified national approach, and collaboration among water companies via a proposed national working group focused on changing customer behaviour regarding blockages.

UKWIR has announced the direction of travel for research projects from now to 2050. The refreshed strategy aims to bring together global trends in water management with impactful research to address UK-specific industry challenges identified through the UKWIR Big Questions and extensive stakeholder engagement.

For more information, visit: ukwir.org/ukwir-announce-new-research-strategy

The water sector needs to build infrastructure at scale over the coming decades. Ahead of her keynote address to the Water Industry Forum on 25 September, Sharon Darcy, chair of the Linear Infrastructure Planning Panel, says competing demands with other sectors over allocation of resources means a collaborative approach is vital.

The water industry faces a monumental challenge: delivering the vast infrastructure needed to meet future demands, while navigating a complex landscape of competing projects in energy, transport and communications.

Projects with robust early stakeholder engagement are more likely to result in success, which is why the Linear Infrastructure Planning Panel (LIPP) works across utility sectors, with representatives from community groups, non-governmental organisations and other external stakeholders, to develop a common language and leading practice on infrastructure planning.

At the Water Industry Forum’s annual dinner in Leeds on 25 September, cross-sector research and insights from LIPP will be shared, which show how planning consent for infrastructure projects can be achieved, and how critical initiatives can be developed and delivered in a cost-effective way that builds community support.

Balancing needs
Balancing national and local needs in infrastructure planning decisions is notoriously difficult, but it is a challenge that needs to be faced if the water sector is going to deliver on net zero carbon, resilience and other national goals. Founded in 2023, LIPP aims to listen and incorporate the perspectives of key public interest stakeholders, including social and environmental groups, in the development of good practice and ethical approaches to the implementation of new techniques, including algorithms and advanced software tools, in linear infrastructure planning.

LIPP published a white paper in March 2024, ‘Delivering net zero, resilience and nature recovery: How new tools and approaches can transform infrastructure planning’, which has already fed into UK Parliament’s Environmental Audit Committee reporting on sustainable electrification. The report draws on intensive engagement with key stakeholders and looks at the social, environmental and economic metrics used in the spatial planning of infrastructure such as electricity transmission lines and major water pipelines.

It highlights new technologies and the changes needed to procurement processes to ensure successful delivery of infrastructure that is essential in meeting net zero targets and resilience to climate impacts. The paper also explores ways of managing uncertainty when developing metrics in these areas, including the need for robust data and ways of ranking and weighing-up different metrics.

Informed decision-making
England faces a critical land shortage. A growing population needs to be housed, while producing enough food, protecting nature and tackling climate change. Despite the intense competition for land, there is no system in place to manage it effectively.

Attendees at the WIF annual dinner will hear a swathe of insights from other industries, such as energy, which can be drawn on to help the water sector navigate current and future challenges. The energy sector is grappling with challenges in grid development, with public opposition to the expansion of power lines needed to transport renewable energy to population centres.

The water sector can learn from these experiences by integrating technical and spatial planning much earlier in the decision-making process. The recent King’s Speech outlining the new Planning & Infrastructure Bill acknowledges the need for advanced spatial planning that considers multiple infrastructure sectors.

By joining up technical planning with spatial planning, learning from other sectors, and through early strategic stakeholder engagement, I believe the water sector will be well-placed to streamline the infrastructure planning process and delivery into the next asset management plan (AMP) period – 2025-30, and beyond.

Sharon Darcy will address the Water Industry Forum Annual Dinner in Leeds on 25 September 2024. To register, visit https://www.britishwater.co.uk/events/EventDetails.aspx?id=1841149&group=

India’s plans to scale up fracking operations without robust regulations could spell disaster for the country’s finely balanced water security, according to research from the University of Surrey. 

India is positioning shale gas as a key transitional energy source and has announced 56 fracking projects across six states. Despite the promise of energy independence, the new study appears to raise alarm bells about the country’s preparedness to handle the unique water risks posed by fracking. 

Hydraulic fracturing, or fracking, involves injecting high-pressure fluid into shale rock to release natural gas. This process has been controversial worldwide due to its significant environmental impacts, particularly on water resources. The study points out that India’s regulatory framework for fracking is currently based on rules designed for conventional drilling processes, which do not adequately address the distinct challenges fracking presents.