Nature as infrastructure: PFAS as an example of why the water sector must reconsider what it values
Jeannette Henderson, Principal – Innovation, Ofwat, discusses the importance of protecting our natural systems while tackling the increasingly pervasive issue of PFAS.
Forever chemicals are forcing the water sector to confront an uncomfortable truth: the most critical infrastructure we manage isn’t pipes or treatment works, but the natural systems we have long treated as expendable.
PFAS (per- and polyfluoroalkyl substances) are synthetic chemicals that are designed to be durable – resistant to heat, water, and oil. As such, they have been coined ‘forever chemicals’. Their durability, while offering merits, is also what makes them so problematic. Once released into the environment, they persist for decades and accumulate in soils, rivers, and ultimately, in our own bodies.
They are used in firefighting foams, across a range of industrial processes, and in many of the products that we rely on every day. From cosmetics and clothing to washing powders and non-stick pans, PFAS are everywhere.
As a result, when we clean our clothes, wash off our makeup, or cook food, traces of PFAS go down the drain. Where PFAS are used and found on land, for example, in industrial sites or in landfills, they can leach into soils and the water table, eventually making their way into rivers and streams.
It is only in recent years that the impact of PFAS has become a focus of attention. The PFAS that enters the wastewater network of drains and sewers will end up at wastewater treatment works. However, most treatment works were never designed to destroy PFAS. Instead, these chemicals end up in sludge, the treated byproduct of our wastewater system.
In England, most sludge produced by water companies is recycled to land as a source of nutrients and organic matter. However, under Defra’s current Sludge (Use in Agriculture) Regulations 1989, there is no consideration of PFAS contamination. This means that PFAS is transferred from wastewater to sludge, to soil, and then into the wider ecosystem.
Discussions in the UK are underway about updating these regulations, in recognition that the existing regime is outdated.
Not only does this consultation signal a recognition that we must do more to tackle the PFAS problem, but it also signals an acknowledgement that soils and water bodies are valuable assets that must be treated in the way in which we treat built assets: with care and urgency.
When a water main bursts, emergency resources are mobilised and funds and people are immediately allocated to repairs. But when PFAS gradually degrade soil health, the impact is slower and less visible. The damage accumulates quietly, often going unnoticed – and our response mirrors this, despite the fact that PFAS are harmful to both our environment and our health.
So, how do we tackle chemicals that are designed not to break down?
We need to both reduce the amount of PFAS entering the environment in the first place and come up with innovative ways to destroy what is already there.
Innovation as the answer
The Water Innovation Fund has recognised this challenge and has supported numerous projects that place nature at the heart of PFAS problem-solving.
One of which is PFAS: A whole system approach to an impossible problem, which is focused on bringing together water companies and research partners to develop and evaluate new treatment methods aimed at removing and destroying PFAS from water. It is led by Severn Trent Water, in partnership with Cranfield University, Hafren Dyfrdwy Cyfyngedig, Scottish Water, Southern Water, Spring Innovation Ltd, Thames Water, and Yorkshire Water.
At present, the teams involved in the project are preparing to test various different PFAS destruction technologies and are continuing to work on ways in which to identify key PFAS compounds to target, to ensure precision. By addressing the persistence of these contaminants, the project seeks to close a critical gap in current water treatment and environmental protection approaches.
Elsewhere, Proving the concept of sewage sludge pyrolysis is a project led by Thames Water, in partnership with Cranfield University, Helsinki Region Environmental Services (HSY), Southern Water, Stantec Ltd, Uisce Éireann, and Yorkshire Water. It is working to deliver the first continuously operating, sludge-fed UK-based pyrolysis demonstration plant by 2029. This will be a new standard for resource recovery and water industry innovation.
Pyrolysis involves heating the sludge to high temperatures in the absence of oxygen. It transforms it into valuable byproducts – biochar and syngas. Biochar is a form of charcoal that can be used to improve soil quality and sequester carbon. Syngas is used as a fuel and in the production of industrial chemicals. Importantly, the high temperatures of pyrolysis destroy PFAS.
This method will maximise the value of biosolids and support a circular economy, reduce the requirement for sludge to be recycled to agricultural land, help destroy PFAS, contribute to net-zero carbon goals and environmental sustainability, and increase operational resilience.
Sewage sludge gasification is another example of a collaborative project that is focused on working with nature, rather than against it. It is led by Yorkshire Water, in partnership with Enertecgreen, Northern Ireland Water, Queens University Belfast, Scottish Water, Southern Water, Thames Water, The Carbon Trust, Uisce Éireann, United Utilities, Wessex Water.
The team has developed an alternative to sludge-to-land, and has innovated to convert it into gas, biochar, and ash stones that are free of PFAS. The hydrogen-rich gas will be used as a clean source of energy, reducing the energy sector’s reliance on traditional energy sources. The biochar is being tested for water filtration and as an additive in brick manufacturing. The ash, too, could be used as an aggregate in the construction of energy.
Embracing change
The UK Government’s consultation on sewage sludge regulation signals an acknowledgement that existing approaches to dealing with PFAS are no longer fit for purpose, and that we must acknowledge that soils and water bodies are valuable components of the water system that we know today.
However, if we are serious about protecting public health and the environment from the impact of forever chemicals, regulation alone will not be enough. We must reshape the water sector’s mindset.
Recent data from the UK Water Industry Research (UKWIR)’s Chemical Investigations Programme (CIP), a partnership between water companies and regulators – including the Environment Agency, Defra and Natural Resource Wales – shows that banning harmful substances at the manufacturer level works.
The Drinking Water Inspectorate has been examining techniques for removing PFAS from drinking water and has commissioned bench and pilot-scale studies. In a nutshell, the results showed that PFAS removal is technically possible, but effectiveness depends heavily on the type of PFAS compound. This reinforces the case for prevention and source protection, not just managing contamination at the tap.
So, where to next? We must embrace stewardship, which demands asking questions at every stage of decision-making about our water system and shifting from short-term visions to long-term plans.
What does a decision taken today mean for soil health in 20 years? For groundwater in 50? For future drinking water security?
Engineering will remain central to this transition, but solutions must be guided by the belief that nature is an equally valuable asset. And the evidence increasingly shows that protecting our natural assets prevents longer-term costs, with nature-based solutions delivering strong economic returns.
When aquifers are contaminated, treatment costs rise. When soils degrade, water quality deteriorates. When ecosystems fail, we use expensive engineered systems as compensation. Investing in nature is investing in infrastructure – infrastructure that has been gifted to us by the planet.
PFAS reveals the limits of an outdated approach. If we continue to treat natural systems as places where residual risk can be exported, we will lock future generations into managing irreversible damage. If we recognise soils, rivers, and aquifers as core assets of the water system, stewardship becomes a catalyst for change.
What’s going on within the Water Innovation Fund?
The Water Discovery Challenge 2 is open until 8 April. Follow this link to find out more.
The Water Innovation Implementation Programme opened on 2 March. Follow this link to find out more.
Two further competitions are due to be announced this year.
