The bucolic image of rolling fields and sustainable farming in Britain is under threat. Beneath the surface lies a concerning practice that could have severe implications for public health and the environment. British farmers are spreading vast quantities of sewage sludge—a mix of human excrement and industrial waste—on agricultural land. This practice, while legal and regulated, is fraught with shortcomings and risks that are poisoning the public indirectly through contaminated food and water. The issue highlights systemic failures, industry profit motives, and government inaction.
What Is Sewage Sludge?
Sewage sludge, also referred to as biosolids, is a by-product of wastewater treatment. It contains human waste, industrial effluents, and a mix of contaminants that are not fully removed during processing. Once treated to remove pathogens, this sludge is sold to farmers as a low-cost fertiliser. While it may provide nutrients to the soil, it also carries harmful substances that can persist in the environment and enter the food chain.
Analysis of official figures by Watershed and The Guardian reveals that the amount of sludge spread on UK fields has grown significantly over the past decade. Between 2012 and 2023, the total volume of sludge produced for spreading rose from 790,923 tonnes to 819,001 tonnes, while the area of land it is applied to increased by 12%, from 135,637 hectares to 151,921 hectares. Most of this land is agricultural, raising concerns about the safety of the food produced on it.
The Role of the Environment Agency
The Environment Agency (EA) is tasked with regulating and policing the use of sewage sludge. However, whistleblowers from the agency have revealed that oversight is insufficient. Industrial waste, often containing a cocktail of hazardous chemicals, enters sewage treatment plants daily, either through sewers or by tanker. Leachates—dirty liquids from landfills—are a particular concern. These liquids contain harmful substances, including per- and polyfluoroalkyl substances (PFAS), often referred to as “forever chemicals” due to their persistence in the environment.
One EA insider described the current situation as a regulatory failure: “What’s going on at the moment is going to be adding potentially significant amounts of contaminants into the wastewater treatment system and therefore what comes out the other end in the final effluent and what comes out in the sludge.” This lack of stringent oversight means contaminants that should be removed or neutralised remain in the sludge that is spread on farmland.
Profits Over Safety
The financial incentives for water companies and industries to dispose of waste via sewage systems are significant. Industries pay water companies to process their waste, making it a lucrative business. However, this profit-driven model raises questions about the robustness of the checks conducted by water companies to ensure harmful substances are removed effectively.
A whistleblower stated, “Water companies give the Environment Agency assurances that they have a process in place for preassessment of the wastes, but I am not in the least bit convinced that that is a very robust system.” This self-policing approach allows industrial waste containing PFAS and other harmful substances to enter the wastewater system, ultimately contaminating sludge.
The agricultural sector benefits from the practice as well, receiving cheap or even free fertiliser. This sludge, however, is far from benign. Studies have shown that contaminants, including PFAS, can persist in soils for decades, leach into groundwater, and accumulate in crops and livestock. This creates a direct route for these harmful substances to enter the food chain and water supplies.
The Threat of PFAS
PFAS are a group of synthetic chemicals used in industrial processes and consumer products, known for their resistance to degradation. Dubbed “forever chemicals,” they pose significant risks to human health, including cancer, hormone disruption, and immune system impairment. The widespread use of PFAS in industrial processes means they are present in landfill leachates and subsequently in sewage sludge.
“An awful lot of tankered effluents are landfill leachates,” said an EA insider. “You can imagine the number of substances, including PFAS, in them. They’re not going to be transformed or destroyed by the wastewater treatment process; they’re going to come out in the effluent or they’re going to end up in sludge.”
Despite the known risks, PFAS are not currently regulated in sludge. The absence of legal limits or mandatory testing allows these chemicals to proliferate unchecked. The consequences are far-reaching, affecting ecosystems, human health, and the integrity of Britain’s agricultural sector.
A Broken System
The sewage sludge cycle exemplifies a broken system where profits take precedence over public safety. Heavy industries save money by disposing of toxic waste through sewers, water companies profit from processing this waste, and farmers receive fertiliser at minimal cost. However, the long-term costs—environmental degradation, public health crises, and eroded trust in food safety—are borne by society.
The EA’s attempts to reform the system have been met with resistance. Insiders report that the Department for Environment, Food and Rural Affairs (Defra) has consistently blocked proposed changes. In 2020, the EA published a strategy for safe and sustainable sludge use, but its implementation has been repeatedly delayed. One EA insider remarked, “The more industrial waste that is put into sewers for the profit of water companies, the more PFAS contaminated water will discharge from outfalls, and the more PFAS contaminated sludge will end up on agricultural land.”
Public Health and Environmental Impact
The implications for public health are alarming. Contaminated sludge can lead to the accumulation of harmful substances in crops, livestock, and water supplies. These contaminants are then consumed by the public, potentially causing serious health issues over time. The environmental impact is equally concerning, as persistent chemicals degrade soil quality, harm wildlife, and pollute waterways.
Water UK, the trade body for water companies, has acknowledged the problem and called for a ban on PFAS. A spokesperson stated, “We want to see PFAS banned and the development of a national plan to remove it from the environment, which should be paid for by manufacturers. In the meantime, water companies are exploring alternatives to spreading sludge to land on a precautionary basis.” However, these measures fall short of addressing the systemic issues that allow the problem to persist.
A Call for Action
Reforming the sewage sludge system requires urgent action from all stakeholders. Key measures should include:
- Stricter Regulation: Establishing stringent legal limits for contaminants like PFAS in sludge and requiring mandatory testing.
- Enhanced Oversight: Increasing the resources and authority of the EA to ensure compliance with regulations.
- Industry Accountability: Making industries responsible for the safe disposal of their waste and funding the development of alternative waste management solutions.
- Public Awareness: Educating the public about the risks associated with sewage sludge and advocating for transparent reporting on where sludge is spread.
Systemic Reform Now
The practice of spreading sewage sludge on agricultural land represents a significant threat to public health and the environment. While it is a cost-effective solution for industries, water companies, and farmers, the hidden costs are borne by the public. The presence of harmful substances like PFAS in sludge underscores the urgent need for systemic reform.
British farmers, water companies, and regulators must prioritise the safety and sustainability of agricultural practices over short-term financial gains. Without decisive action, the contamination of food and water supplies will continue to pose a serious risk to the public and the environment, undermining trust in the very systems meant to protect us.
