PFAS: What We Know, and What We Don’t

By Maile Lono-Batura, California Association of Sanitation Agencies, Regulations

True to the very nature of per- and polyfluoroalkyl substances, commonly referred to as PFAS, these compounds have become pervasive not only in products used in our daily lives but also our conversations surrounding the essential public service of delivering clean water, sanitation, and renewable resources.

Maile Lono-Batura, California Association of Sanitation Agencies

The most efficient and cost-effective way to move forward is clear: remove these chemicals from the stream of commerce for non-essential uses as soon as possible and assign liability for cleanup to those responsible for their manufacture and use. To put this concept into perspective, the Minnesota Pollution Control Agency has noted that PFAS can be bought for $50 – $100 per pound, but costs between $2.7 million and $18 million per pound to remove and destroy from municipal wastewater (depending on facility size).^[1] The most costly option is treating PFAS at the ‘end’ of its consumer road trip at the expense of public ratepayer dollars.

The solution for how to deal with the residual legacy of PFAS in our environment and waterways is not as simple. PFAS have been woven into the very fabric of our lives for decades, and we are now tasked with unstitching ourselves from what was once billed as a miracle additive to products of broad-scale use. The pressing question is how to effectively decouple society from this PFAS dependency while reclaiming our natural systems damaged by these compounds, and reimagining the critical role of the circular water economy in modern society.

A good start in discerning options moving forward is knowing what we know and don’t know. There has been a great deal of focus, both in the media and elsewhere, surrounding the role of biosolids (the residual solids by-product of the wastewater treatment process) in PFAS exposure. There is also a great deal of misinformation, or misunderstanding, about biosolids generally and the risks and benefits they pose. Compiled here is a “kickstarter” of sorts that can be referred to and built upon as this era of PFAS continues to unfold.

Knowns

• PFAS released to the environment continues to decline as products containing PFAS are phased out. PFAS exposure to the environment and living beings is higher at the point of manufacture and use. Daily household exposure from a wide variety of products represents a far more direct point of use exposure than biosolids. As such, from a risk assessment perspective, the point of exposure is critical and necessary to consider when comparing daily home exposure to the more attenuated potential impacts of biosolids.
• Non-industrially impacted biosolids have a long history of safe application and no instances of documented adverse health effects. Decades of research on this practice support land application as the best end use of biosolids. Further, all biosolids must meet quality standards mandated by federal and local laws to be utilized.
• The biosolids ban enacted in Maine stems from the historical use of PFAS-contaminated paper mill sludges and biosolids that received wastewater from a paper plate manufacturing facility before PFAS was a known hazard. There needs to be a clear differentiation between the fate and transport of PFAS from industrially impacted biosolids versus typical municipal biosolids without significant inputs.
• Pretreatment and source control programs at wastewater agencies are very effective at keeping known, targeted, and identifiable sources of contaminants from entering the treatment system. This proven, affordable approach works well in addressing industrial sources, but cannot be used to eliminate PFAS from entering our systems altogether.
• Effective sanitation is one of the most essential developments of the 20th century, and flushing is a reality of modern life. Efforts and proposals limiting management options for byproducts of the wastewater treatment process (i.e. biosolids) will undermine necessary water treatment works, reversing decades of protecting our waterways, ecosystems, and human health.

Unknowns

• While the U.S. EPA recently released its draft PFAS Risk Assessment for biosolids, it is unclear how these comments will shape the final Risk Assessment and when the risk management portion, which includes a relative risk baseline assessment, a cost-benefit analysis, and alternative management options such as source control, will be released.
• While PFAS treatment options continue to be researched, we do not yet know whether there is an efficient and cost-effective means of removing PFAS on a large scale during the wastewater treatment process and whether that translates to the removal of any residual PFAS from biosolids.
• There are few, if any, viable alternatives to land application for biosolids management. Land application remains the most effective, efficient, and beneficial use of biosolids, and there are no viable alternative solutions in the near term.
• Research on the fate of PFAS in non-industrially impacted land-applied biosolids will be released in 2025 through the National PFAS study from the University of Arizona in addition to numerous other key studies. This promises to be a more representative sample of risk from standard biosolids across the country. Preliminary results find negligible migration of PFAS through the soil profile.

We know why biosolids are produced, we know the options that exist, and we know what will transpire if the end-use options disappear. Coupling this with other real-world conditions like breaking records in population, heat, wildfires, loss of topsoil, and lack of access to water and sanitation, the value of these regenerative resources like biosolids will hopefully become more apparent before we try to wipe them from existence. By grounding the conversation in what we know and what we don’t, we can continue the hard work of threading our new vision towards a more circular water society.

With this in mind, CASA, on behalf of the wastewater sector, has been proactively working to limit the uses of PFAS in commerce through various legislation and collaborative efforts with other interested stakeholders in the academic, scientific, and environmental NGO communities. Our objective is to address PFAS contamination at the source and to ensure that the issue of PFAS in wastewater and biosolids is presented factually, with the appropriate context, and in consideration of the best available science.

^[1] Minnesota Pollution Control Agency, 2023. “Evaluation of Current Alternatives and Estimated Cost Curves for PFAS Removal and Destruction from Municipal Wastewater, Biosolids, Landfill Leachate, and Compost Contact Water.” https://www.pca.state.mn.us/news-and-stories/groundbreaking-study-shows-unaffordable-costs-of-pfas-cleanup-from-wastewater