Bioresources

Where wastewater treatment processes do remove PFAS, these forever chemicals can be present in the resulting biosolids which can be used as a fertiliser for land.

Using biosolids as a fertiliser is a long-established and independently regulated process that provides a useful source of nutrients for farming. This saves farmers money and decreases their reliance on chemical fertilisers.

Currently there is no regulation or guidance on PFAS levels in biosolids or a standard assessment methodology in the UK nor is there a viable technology to remove PFAS from sludge.

Our most recent round of sample reporting in 2024 showed we were below the Norwegian standard, which is one of several which can be used to indicate PFAS levels in the absence of UK regulation.  We have increased our sample frequency to build a bigger dataset to inform our actions and programmes of work and respond to the changing regulatory environment.   

We are working with the water sector, research organisations and regulators to better understand this area and are championing two research proposals to improve knowledge through UKWIR.  The first is to examine the potential impacts of PFAS in biosolids upon environmental and human health; the second will identify specific types of trade effluent and tankered waste that represent the highest risk for specific substances in biosolids.

We are committed to understanding the presence, concentration and variability of PFAS in sludge by engaging in relevant research and monitoring. Our current five-year plan for 2025 to 2030 includes a monitoring programme of enhanced biosolids quality surveillance which will include PFOS, a member of the PFAS family, as a substance of interest. Through the fourth phase of the Chemicals Investigation Programme, known as CIP4, our plan will also include further investigation into PFOS and other members of the PFAS chemical family in sludge.