‘No Plan B’: Water companies fear pollution crackdown will stop them spreading sewage sludge on farmland

Water companies are panicking they will be left unable to dispose of millions of tonnes of sewage sludge due to tougher pollution rules and rising concern over the contaminants it contains, an Unearthed investigation has found.

An analysis for trade association Water UK last year found that in a “worst-case” scenario the industry could be left with “3.4 million wet tonnes” of sludge with nowhere to go, documents obtained under freedom of information laws show. 

Sewage sludge is the human faeces and other solids left behind when wastewater is cleaned. Currently around 90% of the UK’s sludge is treated and spread on farmland, where it is used as a rich source of the nutrients needed to fertilise crops. However, concern is rising in the UK that this could be introducing damaging levels of contamination to agricultural land. 

Earlier this year, environmental regulators in the United States warned that toxic PFAS “forever chemicals” in sewage sludge spread on American pasture were posing a cancer risk to people who regularly ate meat or dairy from those farms. 

This came after investigations by Unearthed and others found that sludge destined for British farmland also contained a range of harmful contaminants, including microplastics and forever chemicals.

The water companies fear that increased scrutiny of sludge-spreading in the UK could trigger a “backlash” akin to the public outrage they have faced over sewage released into rivers and seas. 

This crisis was entirely foreseeable, and it is a case of gross negligence that they are now unprepared

 

– Georgia Elliott-Smith, Fighting Dirty

Documents obtained by Unearthed show England’s environmental regulator, the Environment Agency (EA), has warned internally that British farmers could stop accepting sludge onto their land. A briefing prepared for EA chief executive Philip Duffy last March warned that if farmers – or the major retailers they supply – were to lose confidence in the use of sludge there could be “very serious consequences, as the sludge would have nowhere to go”.

The briefing added that the water industry has “no immediate ‘Plan B’” for the sludge it generates. 

However, the industry’s most-pressing anxiety is that the government will tighten controls on the amount of fertiliser farmers can use. The EA and the Department for Environment, Food and Rural Affairs (Defra) are under pressure to clamp down on excessive muck spreading, which is the country’s leading cause of river pollution. 

But water companies say this would leave them without enough farmland available to get rid of all their sludge.

‘Very large and unquantified costs’

Defra has been undertaking a “rapid review” of its guidance on protecting water from agricultural pollution, and is expected to announce next steps in the coming weeks. Water companies believe reform of the agricultural pollution rules could result in an outright ban on manure spreading in the autumn, when there is less crop-need for nutrients. 

According to Water UK, however, around 70% of sewage sludge is spread in the autumn, and “prohibiting or further constraining that practice would introduce very large and unquantified costs” for the water companies. 

Recent modelling for water companies has found that the industry’s “most likely” scenario in the coming decade will be a shortfall of around 3 million hectares in the amount of farmland it needs to dispose of its sludge. 

While the companies are uncertain how much it would cost to deal with a sudden, dramatic shortfall of this kind, they estimate it would run to hundreds of millions of pounds. Some have suggested that over the longer term, it could reach billions. 

At the extreme, this could result in an unplanned increase in household water bills prior to 2030. The prices water companies can charge over the next half-decade were set last year, in a review by Ofwat. However, the regulator agreed that if any legal change to the sludge regime costs companies more than 10% of income, they can come back to request an emergency increase to their price limits.

Georgia Elliott-Smith, director of the group Fighting Dirty, which is campaigning for better regulation of sewage sludge, told Unearthed the water companies have had plenty of time to improve their sludge management.

Farmers need reassurance that what they’re putting on their land is safe – for soil health, nature, their businesses, and the food we all eat

 

– Martin Lines, Nature Friendly Farming Network

“For at least 10 years, [they] have been fully aware of the growing problems associated with sewage sludge yet, instead of investing in solutions that would protect the environment, human health, and consumers, they have continued to ignore the warnings while paying out massive dividends to shareholders,” she said. 

“This crisis was entirely foreseeable, and it is a case of gross negligence that they are now unprepared. If the government and Ofwat allow water companies to continue their cynical profiteering off the backs of customers, especially at a time when many face unprecedented financial hardship, it will be a national scandal.”

However, a spokesperson for Water UK told Unearthed that the industry was “actively supporting research to understand more” about contaminants in sludge, and was carrying out trials to see if sludge could be used for other purposes, such as alternative aviation fuel. 

“Using bioresources on land is a long-established and independently regulated process that provides a useful source of nutrients for farming,” he said. “The use of bioresources saves farmers money and decreases their reliance on chemical fertilisers.”

He also called for tougher government action on PFAS, a class of chemicals that are widely used in products like non-stick cookware, firefighting foam and clothing. PFAS have become a major environmental problem because they do not break down in the environment – earning them the name ‘forever chemicals’ – and have been linked to health problems including developmental delays in children, decreased fertility, and cancers. 

“The UK government has banned the sale of some products containing microplastics and we need the same action on PFAS,” he said. “We also need a national plan to remove it from the environment, which should be paid for by the polluting manufacturers.”

A Defra spokesperson told Unearthed: “We need to see the safe and sustainable use of sludge in agriculture to help clean up our waterways.” 

She added that the Independent Water Commission, led by former Bank of England deputy governor Sir Jon Cunliffe, would continue to “explore a range of issues, including the regulatory framework for sludge spreading”.

This commission was set up by the government last year to review regulation of the privatised water companies, in response to widespread public anger about bills and sewage releases. In interim findings published last week (June 3), the commission concluded that the water sector in England and Wales was failing and needed tougher regulation. 

The EA, which shares a press office with Defra, did not provide a separate statement for this story.

Ofwat also declined to comment. However, Unearthed understands that in last year’s price review the regulator agreed to £716m of water company spending to improve sludge treatment and disposal. This spending is priced into the bills that have already been announced for the coming half decade.

Hazardous waste

The water pollution controversy is not the industry’s only reason to fear a future clampdown on sludge spreading. 

The EA has known for years that existing regulations are inadequate to deal with the chemical complexity of modern sludge, and has been calling for greater powers to deal with the risks it poses. 

“Historically sludge and its contaminants have been neglected,” warned the internal EA briefing to its chief executive last year, “with contaminants being partitioned into the sludge and being spread to land whilst the cleaned-up effluent is discharged to rivers”.

The regulations that control sludge spreading were introduced in 1989 and have barely changed since then. They are focussed mainly on killing bacteria and limiting concentrations of heavy metals in the sludge. 

We know, however, that sludge now contains a much wider range of hazards. 

A secret 2017 report for the EA – uncovered by an Unearthed investigation – found that sludge destined for English farms contained persistent organic pollutants like dioxins, furans and polycyclic aromatic hydrocarbons at “levels that may present a risk to human health”, as well as PCBs, the forever chemical PFOS, microplastics, and pesticides. 

There are no legal limits for these contaminants in sludge, nor are they routinely tested for.

Since this was revealed in 2020, scientists have continued to uncover new evidence about the risks posed by these pollutants.  A James Hutton Institute study, published earlier this year, found that just four years of sludge spreading increased the amount of microplastics in soil by up to 1,450%. This contamination then persisted in the soil for decades after spreading had ceased.

The study’s lead author, Dr Stuart Ramage, told Unearthed: “Over the last decade, research has been uncovering more and more of the hidden impacts of microplastics and the damage they can exact upon soils, especially agricultural soils.” 

Water UK’s spokesperson said: “Although there are some concerns that some bioresources may contain contaminants, such as microplastics and forever chemicals (PFAS), there are no legal standards for them and, in some cases, no agreed assessment techniques. 

“Any standards and techniques are a matter for the government and the regulator and need to be based on firm evidence and detailed scientific research.”

In response to weaknesses in the current system, the EA has developed a “sludge strategy”. The regulator’s plan is to bring sewage sludge into the same environmental permitting regime (EPR) it uses to regulate other industrial activities that can harm the environment. 

This would give the EA greater control over the use of sludge in farming. Water companies expect that in turn the EA would significantly constrict the amount of sludge they can spread on farmland. 

This strategy was first issued in 2020, but cannot be implemented without a change in the law, and therefore needs government support. The EA failed to get the legal change it needed under the previous government.

The failure of the government to enforce [these rules] by introducing loopholes has had catastrophic consequences for many iconic UK rivers

 

– Charles Watson, River Action

However, the regulator may now have some support for reform from the Independent Water Commission. The commission’s interim report, published last week, said sludge use had “significant impacts on the water environment” and the fact that it was not controlled by the EPR represented a “potential gap” in regulatory oversight.

It is likely some contaminants in sludge come from household waste. However, some people within the EA are concerned that the situation is made worse by contracts the water companies have with business customers, allowing them to dispose of industrial wastes in the sewer system.

“Some industrial wastes, such as landfill leachate and chemical wastes, are disposed of down the domestic sewer system,” a source within the agency told Unearthed. “The contaminants find their way into sewage sludge because they are insoluble or bind to solid matter, bypassing the main treatment phase at a sewage works.” 

The source added: “The majority of the industrial wastes disposed to sewer would meet the criteria to be classed as hazardous waste, as would the resulting sludge.”

The UK sewage system was designed to treat both domestic and industrial waste. However, Unearthed understands that Defra has backed a programme of research by the water industry, dubbed the Chemicals Investigation Programme, which is gathering evidence about how some chemicals are not being destroyed by this treatment process.

“Many European countries have implemented more stringent regulations for sewage sludge management compared to the UK,” Evina Katsou, professor of water engineering at Imperial College London, told Unearthed.  

Other countries, for example, “require testing for contaminants such as microplastics, pharmaceuticals, and PFAS in sewage sludge, and if the sludge fails to meet these standards, it cannot be applied to farmland.”

“As a result of concerns surrounding these contaminants, Switzerland and the Netherlands have taken a proactive stance by banning the use of sewage sludge on farmland altogether.”

‘Catastrophic consequences’

Water industry documents suggest the biggest threat to its sludge-spreading practices would be the government changing its guidance on the ‘farming rules for water’. 

These rules, which came into force in 2018, are intended to prevent water pollution caused by excessive muck spreading. 

When a farmer spreads more manure than a crop can absorb, it can increase the risk of “runoff”. This is when rain washes nutrients like nitrogen and phosphorus off the land and into rivers or lakes.

These nutrients can build up in water, causing explosive blooms of algae that ultimately drain the water of oxygen, killing off fish and other animals and creating underwater “dead zones”.

This kind of agricultural pollution is one of the main causes of harm to England’s rivers – a bigger problem even than sewage releases. 

Under the farming rules for water, farmers are prohibited from spreading manure or artificial fertiliser if it exceeds the needs of the soil and crop. The EA has interpreted this to mean that farmers should not spread more manure than is needed at the time – an interpretation that caused outrage among farmers, who said it would effectively ban muck spreading in autumn.

After intensive lobbying by farmers, Defra published “guidance” in 2022 which gave a more permissive interpretation of the rules, allowing autumn spreading to continue. 

However, that guidance has since come under pressure from both the courts and the Office for Environmental Protection (OEP). 

Last May, following a legal challenge by anti-pollution campaign group River Action, a High Court judge concluded that the EA’s interpretation was correct, and nutrients have to be spread at the time they are needed. Then, in November, the OEP launched an investigation, saying Defra’s current guidance “may be unlawful”.

The following month, Defra began a ‘snap review’ of its own guidance.  

River Action chairman Charles Watson told Unearthed that the farming rules for water were introduced “specifically” to prevent the overuse of slurry and fertiliser from polluting waterways, but “the failure of the government to enforce them by introducing loopholes” has had “catastrophic consequences for many iconic UK rivers.”

In May, Defra ministers told the House of Lords that they planned soon to begin a ‘process of reform’ of farming regulations, and would ‘imminently’ publish some ‘updates’ to the farming rules for water. 

Worst-case scenario

When water companies realised the threats facing the current sludge spreading regime, they commissioned a study called the National Landbank Assessment to model the likely impact. 

This modelling was updated last year, and Unearthed obtained a copy of the latest report using FOI laws. 

The study found that the most likely scenario over the coming decade included an increase in sludge production, a ban on most autumn sludge spreading, a drop in farmer demand due to concern over contaminants, and other restrictions. 

These pressures combine to drive up the amount of farmland water companies need while driving down the land available, leaving the industry with a shortfall of 3 million hectares – an area greater than Wales.

In the industry’s “plausible worst case”, the modelling showed this shortfall could grow to more than 10 million hectares.

The water industry recognises that a shortfall could open up suddenly, driven by changes in regulation and farmer sentiment. 

So last year Water UK commissioned another study to model what the industry could do if it was hit with either of these scenarios in 2025. Unearthed also obtained a copy of this modelling – dubbed National Plan B – under the FOI Act. 

It shows that in any situation where there is a sudden shortfall, the majority of excess sludge would have to go to landfill. However, Britain would rapidly run out of space to bury this waste. Even in the “best case scenario”, the last landfill available for sewage sludge would close in 2032 – and the the water companies would be left with a “capacity shortfall of 2.1 million wet tonnes”.

In the industry’s worst case scenario, a proposed ban on the landfilling of biodegradable waste would come into effect in 2028, leaving it with a “capacity shortfall of 3.4 million wet tonnes” in just three years time. 

The report also found regional differences in landfill capacity. It established there is “no in-region landfill capacity” in Wales and that any surplus sludge would need to be sent “immediately” to the midlands.

Another option would be to incinerate sludge, but the report notes there is only one technically capable incinerator in the UK that could deal with it. Waste incinerators emit climate-warming CO2, and air pollution that can cause health issues.  

“It is likely that the planning, construction, and commissioning of new mono-incineration capacity could take a decade or more to implement”, the analysts concluded.

Burning bridge

Both the water companies and the EA recognise that one of the biggest impacts on sludge spreading could come from a change in public sentiment.

“There is a potential ‘burning bridge’ issue of confidence between the sludge producers (water companies) and farmers,” the internal EA briefing warned.

“If there was a loss of confidence by either farmers or the retail consortiums in the use of sludge this could lead to very serious consequences, as the sludge would have nowhere to go.”

The water companies – which have faced enormous public anger in Britain over their discharges of sewage into rivers and seas – fear a similar shift in public awareness over sludge could rapidly leave farmers unwilling to spread it on their land. 

“A backlash akin to what we are experiencing with combined sewer overflows,” states a Southern Water strategy document, could “force retailers to rethink how they source some of their products, in turn impacting farmers’ operation”. 

Though modelling for the water companies does not present a large public backlash as the most likely risk facing their sludge operations, it suggests it could have “substantial effect”.

The issue, they fear, could be pushed into prominence by a growing scandal over sewage sludge contamination in the US and rising media interest in the UK.

“There has been a huge increase in interest in biosolids recycling to land,” states an Anglian Water document from August 2024. “This is particularly notable in the USA and has even resulted in bans on biosolids use in some counties and states.” 

“Although the situation is not currently so stark in the UK,” it continued, “there has been a significant increase in media articles and even a Judicial Review launched against the EA/Defra.”

“Such interest has the potential to have an impact on public and farmer acceptance or even make biosolids recycling not viable with little or no warning.”

Professor Rupert Hough, from the James Hutton Institute, told Unearthed: “The market confidence for using sewage sludge is being challenged because the regulatory framework has not kept pace with our understanding of the chemical composition and risks of sewage sludge. 

“Farmers have always had the same concerns about these products – there is an uncontrolled element around what ends up going down the drain.” 

He added that for farmers to be confident in a product it “needs to meet a quality standard”.

Martin Lines, a Cambridgeshire farmer and head of the Nature Friendly Farming Network, told Unearthed: “Many farmers I speak to have been using sewage sludge for years as a cost-effective way to recycle nutrients and organic matter back into their soils. But it’s becoming harder for farmers to have confidence in what’s being spread on their land when the current regulations only cover a limited set of heavy metals. 

“Farmers need reassurance that what they’re putting on their land is safe – for soil health, nature, their businesses, and the food we all eat. That means proper testing, stronger regulation, and a clear plan to deal with the contaminants already in the system, not just passing the risk onto farmers and the public.”

Unlike with the farming rules for water, if a public backlash suddenly closes off farms to sludge spreading the water companies will not be able to go back to Ofwat to ask for an emergency price rise.