Paper Mill PFAS Discharge: Challenges and Solutions in Mitigating Contamination

Introduction

Paper mills have become a focus of PFAS investigation because of how some papers and packaging were historically made. Mills producing grease- and water-resistant paper — food packaging, fast-food wrappers, and similar products — used PFAS-based treatments to achieve those properties. PFAS from these processes can leave a mill through three routes: wastewater discharge, air emissions, and — often overlooked — the wastewater treatment sludge that mills historically spread on farmland. This article covers where PFAS in paper mills comes from, the regulatory framework, the treatment options available for mill wastewater, and why source control and residuals management matter as much as end-of-pipe treatment.

Mill wastewater is one of many industrial applications for PFAS treatment, and the technologies involved are compared across municipal and industrial uses in our overview of PFAS treatment systems.

Understanding PFAS: Chemical Properties and Sources

What are PFAS?

PFAS, commonly called “forever chemicals,” are synthetic compounds defined by carbon-fluorine bonds, among the strongest in organic chemistry. That structure gives them resistance to heat, water, and oil — the properties that made them valuable in paper coatings — and also their resistance to breaking down in the environment.

Sources of PFAS in Paper Mills

The principal use of PFAS in papermaking has been grease and oil resistance for food-contact paper and packaging. This was typically achieved with side-chain fluorinated polymers and other fluorotelomer-based treatments, applied either within the paper furnish or as a surface coating.

Several points follow for mill wastewater:

• Fluorotelomer-based treatments contain and can release precursors that are not measured by standard targeted analysis but can degrade into regulated perfluorinated acids in the environment or during wastewater treatment.
• Mills that never used PFAS-based treatments may still receive PFAS through recycled fiber, since recovered paper and packaging can carry PFAS into the process.
• Use of PFAS-based grease-proofing in U.S. food packaging has declined sharply, and the FDA has reported that such grease-proofing substances are no longer being sold for food-contact use in the U.S. market. Legacy contamination, recycled fiber, and imported products remain concerns.

The Residuals Pathway: Mill Sludge and Land Application

For many mills, the largest PFAS issue has not been effluent but sludge. PFAS in mill wastewater partition significantly to the primary and biological treatment solids. Where those residuals — alone or mixed with municipal biosolids — were applied to agricultural land as a soil amendment, PFAS accumulated in soil and migrated to groundwater.

Maine became the best-known example. Investigations there linked land application of paper mill residuals and municipal biosolids to PFAS contamination of farmland, private wells, and agricultural products, and the state prohibited land application of sludge and biosolids in 2022. Contaminated groundwater at such sites often requires long-term remediation, including extraction and treatment approaches described in our discussion of pump and treat for PFAS.

Regulatory Landscape: Navigating Compliance

Key Regulatory Frameworks

1. Clean Water Act (CWA): Mill discharges are governed by NPDES permits and effluent guidelines. EPA has encouraged states to add PFAS monitoring to industrial NPDES permits, and in 2024 finalized EPA Method 1633 for measuring PFAS in wastewater, surface water, groundwater, soil, biosolids, and tissue, giving permitting authorities a standardized analytical basis. Some states now require PFAS monitoring or pretreatment for industrial dischargers.

2. Safe Drinking Water Act (SDWA): The SDWA regulates public water systems, not industrial dischargers. However, EPA’s 2024 drinking water limits of 4.0 parts per trillion for PFOA and PFOS — which EPA proposed in May 2026 to retain, with an optional compliance extension to 2031 — increase pressure on dischargers upstream of drinking water intakes, as utilities and regulators look to control PFAS at the source.

3. Toxic Substances Control Act (TSCA): TSCA governs the manufacture and use of chemicals, including PFAS. Reporting requirements for PFAS manufactured or imported into the U.S. affect the chemical supply chain on which mills depend.

4. State Programs: Several states regulate PFAS in food packaging, biosolids and residuals management, and industrial discharges. These state programs frequently move faster than federal action and are often the binding requirement for mills.

Environmental and Health Implications of PFAS Discharge

Ecosystem Impact

PFAS bioaccumulate in aquatic organisms, particularly long-chain compounds such as PFOS. Fish consumption advisories for PFAS have been issued for water bodies in many states, reflecting accumulation from industrial and other sources.

Human Health Effects

Exposure to PFAS has been associated with elevated cholesterol, immune effects including reduced vaccine response, and certain cancers. Pregnant women and young children are considered particularly vulnerable. Communities near land-applied residuals may be exposed through private wells and locally produced food, not only through surface water.

Treatment Solutions for Mill Wastewater

Why Mill Effluent Is Difficult to Treat

Paper mill wastewater presents a challenging matrix for PFAS treatment: very large flows, high organic content, color, and suspended solids. Organic matter competes for adsorption sites and fouls media, and high flow makes any end-of-pipe PFAS treatment expensive. These characteristics are why source control is usually the first and most cost-effective strategy.

Technological Approaches

1. Activated Carbon: Granular activated carbon adsorbs PFAS, particularly long-chain compounds, but high organic loading in mill effluent shortens bed life considerably. Contact time is a key design parameter, discussed in our coverage of empty bed contact time for PFAS. Effective pretreatment is essential to make carbon economical.

2. Ion Exchange Resins: PFAS-selective anion exchange resins can offer higher capacity and better short-chain performance than carbon, but are sensitive to organic fouling and competing anions. They are most practical on pretreated or segregated streams.

3. Membrane Technologies: Nanofiltration and reverse osmosis reject PFAS effectively, but mill flows and fouling potential make them costly, and they produce a concentrate that must be managed.

4. Foam Fractionation: Exploits the surfactant behavior of PFAS to concentrate them into a small foam volume. Its tolerance of high-organic, high-solids water makes it worth evaluating for industrial effluents.

A note on advanced oxidation: conventional advanced oxidation processes based on hydroxyl radicals — ozone or UV/peroxide — do not mineralize perfluorinated compounds such as PFOA and PFOS, and can convert fluorotelomer precursors into regulated PFAS. They are not a PFAS treatment for mill wastewater. Destruction technologies such as electrochemical oxidation or supercritical water oxidation are applied to concentrated streams produced by separation, not to full effluent flows.

Stream Segregation

Where PFAS enter the mill at identifiable points — a coating line, a specific product grade, or a recycled fiber stream — treating that stream separately before it mixes with the full mill effluent can reduce treatment volume and cost dramatically.

Best Management Practices

• Source control first: Eliminate PFAS-based chemistries from the process and verify supplier formulations. Removing PFAS at the source is almost always cheaper than removing it from effluent.
• Characterize fully: Monitor influent, effluent, and residuals using Method 1633, and consider the total oxidizable precursor assay where fluorotelomer chemistry was used.
• Manage residuals: Test sludge before any land application or beneficial use, and evaluate disposal options in light of state restrictions.
• Screen recycled fiber: Understand the PFAS contribution of recovered paper inputs.
• Plan for tightening requirements: Develop a PFAS reduction plan that anticipates state and federal developments rather than reacting to them.

Conclusion: A Path Forward

PFAS discharge from paper mills is best understood as a source, effluent, and residuals problem together. The historic use of PFAS for grease resistance in food packaging is the root source; wastewater discharge is one pathway; and land application of mill residuals has proven to be among the most consequential routes to farmland and groundwater contamination.

Because mill effluent is high-volume and organically loaded, end-of-pipe PFAS treatment is expensive, and source control and stream segregation deliver the greatest benefit per dollar. Where treatment is required, activated carbon, ion exchange, membranes, and foam fractionation are the realistic options, each dependent on effective pretreatment. Full characterization of effluent and residuals, including precursors, provides the foundation for decisions that protect both compliance and the communities downstream.