Jeannette Henderson, Principal of Innovation at Ofwat, talks about the importance of protecting natural systems while tackling the increasingly prevalent problem of PFAS.
Chemicals forever force the water sector to face an unpleasant reality. That means the most important infrastructure we manage is not pipes or treatment facilities, but natural systems that we have long treated as expendable.
PFAS (per- and polyfluoroalkyl substances) are synthetic chemicals that are resistant to heat, water, and oil. That is why they are called “eternal chemicals”. While durability has its benefits, it can also be very problematic. Once released into the environment, they persist for decades, accumulating in soil, rivers, and ultimately our own bodies.
They are used in firefighting foams, various industrial processes, and many of the products we use every day. PFAS are used everywhere, from cosmetics and clothing to detergents and nonstick pans.
As a result, when we wash our clothes, remove our makeup, and prepare our food, trace amounts of PFAS end up in our drains. When PFAS are used and found on land, for example in industrial sites or landfills, they can leach into soils and groundwater tables, and ultimately into rivers and streams.
It is only in recent years that the effects of PFAS have received attention. PFAS that enter the wastewater network of drains and sewers end up in wastewater treatment facilities. However, most treatment efforts were not designed to destroy PFAS. Instead, these chemicals end up in sludge, a treated byproduct of wastewater systems.
In the UK, most of the sludge produced by water companies is recycled back into the land as a source of nutrients and organic matter. However, Defra’s current Sludge (Agricultural Use) Regulations 1989 do not take PFAS contamination into account. This means PFAS migrate from wastewater to sludge, soil, and the broader ecosystem.
Discussions are underway in the UK about updating these regulations as the existing system is recognized to be outdated.
This consultation not only recognizes that we need to do more to tackle the PFAS issue, but also recognizes that soil and water are valuable assets that must be treated with care and urgency, in the same way that we treat constructed assets.
When a water main ruptures, emergency resources are mobilized and funds and personnel are immediately allocated to repairs. But as PFAS degrade soil health over time, their effects are slower and less visible. Despite the fact that PFAS are harmful to both the environment and health, the damage accumulates silently and often goes unnoticed. And our response reflects this.
So how do we deal with 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’s already there.
Innovation as the answer
The Water Innovation Fund recognizes this challenge and has supported numerous projects that put nature at the center of solving the PFAS problem.
One of them is PFAS. It’s a whole systems approach to impossible problems. It focuses 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 Dyfrodwy Saifingedig, Scottish Water, Southern Water, Spring Innovation Limited, Thames Water and Yorkshire Water.
The team involved in this project is currently preparing to test a variety of PFAS destruction techniques and continues to work on developing methods to identify the primary PFAS compounds to target to ensure accuracy. This project aims to fill a critical gap in current water treatment and environmental protection approaches by addressing the persistence of these pollutants.
Elsewhere, a proof-of-concept project for pyrolysis of sewage sludge is being led by Thames Water in collaboration with Cranfield University, Helsinki Regional Environmental Services (HSY), Southern Water, Stantec, Uis Alien and Yorkshire Water. The company is committed to delivering the first continuously operating pyrolysis demonstration plant based in the UK and supplying sludge by 2029. This will set a new standard for resource recovery and water industry innovation.
Pyrolysis involves heating sludge to high temperatures in the absence of oxygen. It is converted into biochar and syngas, which are valuable by-products. Biochar is a type of charcoal that can be used to improve soil quality and sequester carbon. Synthesis gas is used as a fuel and in the production of industrial chemicals. Importantly, high temperature pyrolysis destroys PFAS.
This method maximizes the value of biosolids, supports a circular economy, reduces the need to recycle sludge to farmland, supports the destruction of PFAS, contributes to net-zero carbon targets and environmental sustainability, and increases operational resilience.
Gasification of sewage sludge is another example of a collaborative project that focuses on working with nature rather than against it. It is led by Yorkshire Water and in partnership with Enertech Green, Northern Ireland Water, Queen’s University Belfast, Scottish Water, Southern Water, Thames Water, Carbon Trust, Uis Eireann, United Utilities and Wessex Water.
The team developed an alternative way to return the sludge to land, innovating to convert it into PFAS-free gas, biochar, and ash. Hydrogen-rich gas can be used as a clean energy source, reducing the energy sector’s dependence on traditional energy sources. Biochar has been tested as an additive in water filtration and brick manufacturing. Ash also has the potential to be used as aggregate in energy construction.
embrace change
The UK Government’s consultation on sewage sludge regulation shows that it recognizes that existing approaches to dealing with PFAS are no longer fit for purpose and that we need to recognize that soils and waters are valuable components of water systems as we know them today.
But if we are serious about permanently protecting public health and the environment from the effects of chemicals, regulation alone is not enough. We need to rethink the water sector.
Recent data from the UK Water Industry Research (UKWIR), a partnership between regulators including the UK Water Industry Research (UKWIR) Chemical Inspection Program (CIP), the Environment Agency, Defra and Natural Resources Wales, shows that bans on hazardous substances at manufacturer level are working.
The Drinking Water Inspection Service is investigating technologies to remove PFAS from drinking water and has commissioned bench-scale and pilot-scale studies. In short, the results showed that PFAS removal is technically possible, but effectiveness is highly dependent on the type of PFAS compound. This strengthens the case for prevention and source protection, as well as control of pollution at the faucet.
So, where do you go next? We must embrace stewardship, which requires questioning every step of decision-making about our water systems and moving from short-term vision to long-term planning.
What will decisions made today mean for soil health in 20 years? For groundwater in 50 years? To ensure the safety of future drinking water?
Engineering will continue to be central to this transition, but solutions must be guided by the belief that nature is an equally valuable asset. And there is growing evidence that protecting natural assets prevents long-term costs, with nature-based solutions delivering strong economic benefits.
When aquifers become contaminated, treatment costs increase. As soil deteriorates, water quality also deteriorates. When an ecosystem fails, we use expensive artificial systems to compensate. Investing in nature is like investing in the infrastructure that the earth has given us.
PFAS exposes the limitations of outdated approaches. If we continue to treat natural systems as sites where residual risks can be exported, we will lock future generations into managing irreversible damage. By recognizing soils, rivers and aquifers as core assets of water systems, management becomes a catalyst for change.
What is happening within the Water Innovation Fund?
Water Discovery Challenge 2 runs until April 8th. Click this link for more information.
The Water Innovation Implementation Program was launched on March 2nd. Click this link for more information.
Two more contests will be announced this year.
This article will be published in an upcoming PFAS Special Focus Publication in April.
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