PFAS Treatment Technologies: Practical Tools and Considerations for Counties

This article is part of MACo’s Policy Deep Dive series, where expert analysts translate complex environmental challenges into county-level clarity.

Counties across Maryland find themselves passive receivers in the PFAS crisis. Though not the polluters, they bear the weight of escalating treatment obligations, uncertain funding, and evolving rules. As a result, every dollar, disposal option, and treatment decision must be weighed against long-term implications.

This deep dive breaks down the EPA’s March 2024 technical support document, which outlines the engineering realities that counties must now consider as stricter state and federal standards become enforceable.

The Technologies: How Systems Can Remove PFAS

EPA highlights three main treatment categories, each with tradeoffs in effectiveness, operations, and cost:

Granular Activated Carbon (GAC)

  • How it works: Water passes through beds of activated carbon that “adsorb” PFAS and other contaminants, trapping them in the carbon-based filter.
  • Effectiveness: EPA data shows GAC removal efficiencies of 90 percent or greater for all PFAS compounds for which data are available. The literature also shows that the technology often removes these compounds to levels below analytical detection limits. For PFOA and PFOS, maximum removal efficiencies are greater than 99 percent, also to below analytical detection limits and lower than current federal regulatory thresholds.
  • Cost drivers: The length of time between GAC replacement is known as “bed life,” and depending on the GAC technology used and size of a system the bed life can range considerably. Shorter bed life means frequent replacement, which adds recurring expense.

Ion Exchange (IX)

  • How it works: Water passes through synthetic resins that swap PFAS ions for harmless ones (like chloride), filtering the PFAS and trapping it within the specialized resins.
  • Effectiveness: EPA data shows IX removal efficiencies of 90 percent or greater for all PFAS compounds for which data are available. The literature also shows that the technology often removes these compounds to levels below analytical detection limits. For PFOA and PFOS, maximum removal efficiencies are greater than 99 percent, also to below analytical detection limits and lower than current federal regulatory thresholds. Compared to GAC, IX has also shown to be more effective at removing PFAS compounds with longer chain lengths.
  • Cost drivers: Depending on the IX technology used and size of a system the bed life can range considerably. Specialty resins are largely more expensive than carbon filters, but they can also last longer under the right conditions increasing bed life.

Reverse Osmosis / Nanofiltration (RO/NF)

  • How it works: Pressurized membranes to physically separate PFAS from water.
  • Effectiveness: EPA data shows RO/NF removal efficiencies of 90 percent or greater for all PFAS compounds for which data are available. The literature also shows that the technology often removes these compounds to levels below analytical detection limits. For PFOA and PFOS, maximum removal efficiencies are greater than 99 percent, also to below analytical detection limits and lower than current federal regulatory thresholds.
  • Cost drivers: Depending on the RO/NF technology used and size of a system the bed life can range considerably. Unlike GAC and IX technology, the data currently shows RO/NF removal efficiency tends to be steady-state and does not vary over time, meaning less of a need to replace costly filters. Alternatively, the requirement of high pressure may mean higher energy use. Additionally, disposal of brine waste (the byproduct of separated contaminants) could add a significant cost.

Non-Treatment Alternatives

EPA emphasizes that not every system will need to build new treatment facilities. In some cases, “compliance by connection” or source replacement may be cheaper and faster:

  • Interconnections: Linking to a nearby system already meeting standards. This can simplify the operational complexity involved in complying with new requirements. Consequently, it may also require long pipelines, booster pumps, and negotiations over wholesale water rates.
  • New Wells: Drilling replacement wells into deeper or uncontaminated aquifers. This will likely have a lower upfront cost than full treatment, but it may also not always be geologically feasible. PFAS can migrate into new sources over time.

Items not Covered in the EPA Paper

Landfilling PFAS-Contaminated Biosolids

One option for managing PFAS-contaminated biosolids—the byproduct of wastewater treatment—is disposal in landfills. Several wastewater treatment plants in Maryland already use this method, but making it the default approach could create new challenges.

  • Capacity Concerns: Maryland’s landfills have limited space, and large-scale reliance on landfilling biosolids could accelerate capacity issues.
  • Leachate Risks: Landfills produce leachate—the liquid that drains through waste. Leachate is already subject to PFAS testing, and future regulations will likely require treatment for PFAS before discharge.
  • PFAS Concentration: Landfilling does not eliminate PFAS; it simply relocates and concentrates them. In the medium term, counties that own or operate landfills will still need to manage this contamination, even if treatment is postponed.

While landfilling provides a short-term outlet, it shifts the problem downstream and onto jurisdictions responsible for landfill management.

Pyrolysis Processing

Pyrolysis is an emerging technology that uses high heat in an oxygen-limited environment to break down organic materials, including PFAS-contaminated biosolids. While it offers potential as a disposal method, several considerations remain:

  • Technology Status: Pyrolysis has shown promise in reducing PFAS concentrations, but it is still largely in the pilot or demonstration stage in the U.S. Full-scale performance data is limited.
  • Byproducts: The process generates gases, oils, and char. These facilities can generate greenhouse gas emissions that may impact the air quality in the communities in which they are developed.
  • Cost & Infrastructure: Pyrolysis systems are capital-intensive and require specialized equipment, high energy inputs, and operator training—posing challenges for county-level deployment.
  • Regulatory Uncertainty: Federal and state regulators are still evaluating pyrolysis for PFAS destruction. Until standards are set, counties face uncertainty about compliance and liability.

Pyrolysis could become a valuable long-term option for managing PFAS-laden biosolids, but for now, it remains experimental. Counties exploring this pathway will need to weigh upfront costs, regulatory clarity, and the risks of managing residual byproducts.

Conclusion

Counties are on the frontlines of the PFAS challenge—not as the polluters, but as the problem-solvers tasked with protecting residents and meeting new regulatory requirements. The EPA’s cost and technology report makes clear there is no one-size-fits-all solution: each option carries tradeoffs in effectiveness, cost, and long-term viability. From proven approaches like carbon and ion exchange, to emerging pathways like pyrolysis, and short-term outlets like landfilling, local leaders must balance immediate compliance with sustainable, long-term strategies. As state and federal standards tighten, Maryland counties need their support through funding strategies, regional collaboration, and proactive planning to ensure safe drinking water and resilient communities.

Read the full EPA Technical Support Document.

Read about the recent PFAS session at the 2025 MACo Summer Conference.

Read about the EPA’s recent moves to rescind certain PFAS limitation.

Read MACo’s Deep Dive – Managing Forever Chemicals: The Road Ahead for PFAS Policy

Read MACo’s Deep Dive – PFAS: What Are They? Why Do They Matter? What’s Next?