Case study: PFAS remediation & emerging contaminants — a city or utility pilot and the results so far

In 2023, the city of Stuart, Florida, discovered PFAS contamination in three of its five municipal drinking water wells at concentrations ranging from 28 to 74 parts per trillion (ppt), well above the US EPA's final Maximum Contaminant Level (MCL) of 4 ppt for PFOA and PFOS established in April 2024. Within 18 months, Stuart had designed, permitted, constructed, and commissioned a granular activated carbon (GAC) treatment system serving 55,000 residents at a total capital cost of $14.2 million. The facility now achieves non-detect levels for six regulated PFAS compounds and has become a reference project for small and mid-size utilities nationwide navigating the same regulatory deadline. Stuart's experience illustrates both the technical feasibility and the institutional complexity of PFAS remediation at the municipal scale.

Why It Matters

PFAS contamination is no longer a localized concern. The US EPA's 2024 National Primary Drinking Water Regulation established enforceable MCLs for six PFAS compounds, triggering compliance obligations for an estimated 4,700 to 6,000 public water systems across the country (US EPA, 2024). The American Water Works Association estimates that total national compliance costs will reach $3.6 billion in capital expenditure and $1.7 billion in annual operating costs once all affected systems achieve compliance by the 2029 deadline (AWWA, 2024).

For municipal leaders, the challenge is threefold: selecting a treatment technology that reliably reduces PFAS below detection limits, financing capital projects on compressed timelines, and managing spent media and concentrated waste streams that themselves contain PFAS. Utilities that delay action face not only regulatory enforcement but also growing liability exposure, as PFAS litigation has produced over $12 billion in settlements since 2023, with municipal water contamination claims representing the fastest-growing category (Environmental Litigation Journal, 2025).

The Stuart pilot demonstrates a replicable pathway for mid-size utilities: targeted source characterization, pragmatic technology selection, creative financing, and iterative operational optimization that has reduced per-unit treatment costs by 22% in the first year of operation.

Key Concepts

PFAS (per- and polyfluoroalkyl substances) are a class of more than 14,000 synthetic chemicals characterized by extremely strong carbon-fluorine bonds that resist environmental degradation, earning them the label "forever chemicals." The six PFAS compounds regulated under the 2024 EPA rule are PFOA, PFOS, PFNA, PFHxS, PFBS, and GenX (HFPO-DA). Each has an individual MCL of 4 ppt, with a hazard index approach applied to mixtures of PFHxS, PFNA, PFBS, and GenX.

Three primary treatment technologies dominate municipal PFAS remediation. Granular activated carbon (GAC) adsorbs PFAS onto carbon surfaces and is effective for longer-chain compounds (PFOA, PFOS) but requires frequent media replacement for shorter-chain species. Ion exchange (IX) resins use selective anion exchange to capture PFAS and can achieve lower effluent concentrations for a broader range of chain lengths but generate concentrated brine waste streams during regeneration. High-pressure membrane systems (nanofiltration and reverse osmosis) physically reject PFAS molecules but produce a PFAS-laden concentrate stream requiring separate disposal or treatment.

Emerging destruction technologies, including electrochemical oxidation, supercritical water oxidation, and sonochemical treatment, aim to break the carbon-fluorine bond and mineralize PFAS rather than simply concentrating them. These technologies are largely at pilot scale, with full-scale commercial deployments expected between 2027 and 2030 (Interstate Technology Regulatory Council, 2025).

What's Working

Stuart's approach succeeded because of several deliberate design and procurement decisions that other utilities can replicate.

Phased source characterization before technology selection. Before committing to a treatment technology, Stuart conducted a comprehensive PFAS source investigation across all five wells, sampling for 40 PFAS analytes (not just the six regulated compounds) and characterizing seasonal variability over six months. This investment of $185,000 in analytical work revealed that contamination was dominated by long-chain PFAS (PFOA and PFOS at 85% of total PFAS mass), making GAC the optimal technology choice. Utilities that skip detailed characterization and default to the most expensive option often overspend by 30 to 50%.

Modular, scalable treatment design. The GAC system was designed with four parallel vessels, each containing 20,000 pounds of bituminous coal-based carbon, configured in a lead-lag arrangement. This modular approach allowed Stuart to bring two vessels online within 8 months while constructing the remaining two, achieving interim compliance ahead of the regulatory timeline. The lead-lag configuration also extends carbon life by 30 to 40% compared to single-vessel designs, because the lead vessel performs the bulk of adsorption while the lag vessel polishes any breakthrough.

Cooperative procurement for carbon supply. Stuart joined a multi-utility purchasing cooperative with four neighboring Florida utilities, negotiating a five-year GAC supply contract at $1.85 per pound versus the spot market price of $2.40 to $2.80 per pound. This cooperative reduced annual carbon replacement costs by approximately $340,000. Similar purchasing cooperatives have formed in Michigan (12 utilities), North Carolina (8 utilities), and New Jersey (15 utilities), demonstrating the scalability of this approach.

Real-time performance monitoring. The facility installed continuous online total organic carbon (TOC) and UV254 absorbance analyzers as surrogate indicators for PFAS breakthrough, supplemented by weekly laboratory PFAS analysis using EPA Method 533. The surrogate monitoring provides 15-minute data resolution versus the 5 to 7 day turnaround for laboratory PFAS results, enabling proactive carbon changeout scheduling that has eliminated any breakthrough events in the first year of operation.

State revolving fund financing. Stuart financed the project through Florida's Drinking Water State Revolving Fund (DWSRF) program, securing a $14.2 million loan at 1.5% interest over 20 years with 30% principal forgiveness under the EPA's Emerging Contaminants funding allocation from the Bipartisan Infrastructure Law. The effective financing cost was 60% below market-rate municipal bond financing, reducing the annual debt service burden from $1.1 million to $680,000.

What's Not Working

Despite Stuart's success, several aspects of the PFAS remediation landscape remain problematic for utilities nationwide.

Spent carbon disposal creates a secondary waste problem. GAC treatment does not destroy PFAS; it transfers the contamination from water to a solid waste stream. Stuart's spent carbon is currently shipped to a high-temperature incineration facility in Arkansas at a cost of $0.85 per pound ($17,000 per vessel changeout). However, EPA's 2025 proposed rule on PFAS destruction during incineration raises questions about whether thermal treatment at conventional temperatures (800 to 1,100 degrees Celsius) fully mineralizes PFAS or generates incomplete combustion byproducts. Some states, including Michigan and Maine, have imposed moratoriums on land application of PFAS-containing biosolids and ash, creating disposal bottlenecks that may affect spent carbon management (Michigan EGLE, 2025).

Short-chain PFAS remain difficult to treat cost-effectively. While Stuart's GAC system performs well for PFOA and PFOS (carbon bed life of 18 to 24 months), shorter-chain compounds like PFBS and GenX break through much faster (carbon bed life of 4 to 8 months) due to weaker adsorption affinity. Utilities with significant short-chain PFAS contamination face carbon replacement costs two to four times higher per unit volume treated. The Cape Fear Public Utility Authority in North Carolina, which contends with GenX contamination from the Chemours Fayetteville Works facility, spent $28 million on GAC and IX treatment systems and reports annual operating costs of $6.2 million for a 44 MGD system, roughly triple the per-gallon cost of Stuart's long-chain-dominated contamination profile (Cape Fear PUA, 2025).

Analytical capacity is a national bottleneck. EPA Method 533 and Method 537.1 require specialized mass spectrometry equipment and trained analysts. The Environmental Council of the States reported in 2025 that only 87 certified laboratories nationwide have the capacity to run these methods, creating sample turnaround times of 3 to 6 weeks during peak compliance monitoring periods. Stuart mitigated this by contracting with two separate laboratories and staggering submissions, but smaller utilities without procurement flexibility face monitoring delays that complicate compliance demonstration.

Source control remains inadequate. Stuart's contamination originated from a combination of legacy aqueous film-forming foam (AFFF) use at a nearby fire training facility and industrial discharge from an electronics manufacturer. Despite identifying the sources, remediation of the contamination plume in groundwater will take decades. The city estimates ongoing treatment costs of $1.8 million per year for at least 15 to 20 years, with no certainty that responsible parties will reimburse costs through litigation. This illustrates a systemic challenge: treatment at the point of use is necessary but does not address the underlying contamination.

Key Players

Established Companies

Calgon Carbon (a Kuraray company): the largest supplier of activated carbon products for water treatment in North America, with a dedicated PFAS treatment product line and reactivation services at facilities in Pennsylvania, Mississippi, and Kentucky.

Evoqua Water Technologies (now part of Xylem): provides turnkey PFAS treatment systems including GAC, IX, and combination trains, with over 150 municipal PFAS installations completed in the US through 2025.

Veolia Water Technologies: operates PFAS treatment systems globally, including the Eau de Paris direct potable reuse facility incorporating GAC and IX treatment for emerging contaminants.

Purolite (an Ecolab company): manufactures single-use PFAS-selective IX resins that eliminate the need for on-site regeneration and the associated brine waste stream.

Startups and Innovators

Aclarity: develops electrochemical oxidation technology for on-site PFAS destruction, with pilot installations at three US military bases demonstrating greater than 99% destruction of PFOA and PFOS in concentrated waste streams.

374Water: commercializing supercritical water oxidation (SCWO) systems for PFAS destruction, with a full-scale unit deployed at Mercer County, New Jersey, processing PFAS-contaminated biosolids at 5 dry tons per day.

Revive Environmental: offers SCWO-based PFAS destruction services targeting AFFF stockpile destruction and concentrated waste stream treatment, with mobile units deployed at Department of Defense facilities.

Cyclopure: produces cyclodextrin-based adsorbent materials (DEXSORB) that selectively capture PFAS with higher affinity than GAC for short-chain compounds, currently in commercial-scale pilot testing with six US utilities.

Investors and Funders

US EPA Bipartisan Infrastructure Law: allocated $9 billion through 2026 for emerging contaminant treatment through DWSRF programs, with PFAS as the primary target.

The Water Research Foundation: funding $15 million in applied research on PFAS treatment optimization, destruction technologies, and analytical methods.

Breakthrough Energy Ventures: invested in multiple PFAS destruction technology startups including electrochemical and plasma-based approaches.

Measured Outcomes

Metric	Pre-Treatment	Post-Treatment (Year 1)
PFOA (ppt)	42-74	Non-detect (<2 ppt)
PFOS (ppt)	28-61	Non-detect (<2 ppt)
Total PFAS (ppt)	85-142	<5
System availability	N/A	98.7%
Carbon bed life (PFOA/PFOS)	N/A	22 months (projected)
Treatment cost per 1,000 gallons	N/A	$0.42
Annual operating cost	N/A	$1.8 million
Capital cost	N/A	$14.2 million

Action Checklist

• Conduct comprehensive PFAS source characterization sampling for 40+ analytes across all supply wells before selecting treatment technology
• Evaluate GAC, IX, and membrane treatment options based on site-specific PFAS profile, with particular attention to short-chain versus long-chain compound ratios
• Design treatment systems with lead-lag vessel configurations to extend media life by 30 to 40% and enable continuous operation during changeouts
• Explore multi-utility cooperative procurement for carbon or resin supply to reduce unit costs by 25 to 35%
• Apply for DWSRF Emerging Contaminants funding, which provides principal forgiveness of up to 49% for disadvantaged communities
• Install continuous surrogate monitoring (TOC, UV254) for real-time PFAS breakthrough detection between laboratory sampling events
• Establish contracts with at least two certified analytical laboratories to mitigate sample turnaround bottlenecks
• Develop a spent media management plan addressing transportation, destruction, and regulatory requirements for PFAS-containing waste
• Pursue cost recovery through litigation or responsible party agreements for contamination sources identified during investigation
• Monitor emerging PFAS destruction technologies for potential integration as they reach commercial readiness between 2027 and 2030

FAQ

Q: How does a utility determine whether GAC or IX resin is the better treatment choice for PFAS? A: The decision depends primarily on the PFAS compound profile in the source water. GAC is cost-effective for long-chain PFAS (PFOA, PFOS, PFHxS) where carbon bed life exceeds 12 months, providing per-unit treatment costs of $0.30 to $0.60 per 1,000 gallons. IX resins are preferred when short-chain PFAS dominate (PFBS, GenX, PFHpA) because their selective chemistry maintains effectiveness where GAC adsorption is weak. However, IX systems using regenerable resins produce a PFAS-concentrated brine that requires treatment or disposal, adding $0.15 to $0.25 per 1,000 gallons to operating costs. Single-use IX resins eliminate the brine issue but cost $8 to $12 per pound versus $1.50 to $2.50 for GAC. Most utilities benefit from pilot testing both technologies at the specific site for 6 to 12 months before committing to full-scale design.

Q: What financing options are available for municipal PFAS treatment projects? A: The Bipartisan Infrastructure Law allocated $9 billion through DWSRF programs specifically for emerging contaminants, with up to 49% principal forgiveness for disadvantaged communities. States administer these funds through their revolving fund programs, with application cycles typically opening annually. Additionally, the 3M PFAS settlement ($10.3 billion) and Chemours/DuPont settlements ($1.19 billion) are distributing funds to affected water systems, though the claims process is competitive and requires documented PFAS contamination and treatment costs. USDA Rural Development grants (up to $2 million) and EPA WIFIA loans (for projects exceeding $20 million) provide supplemental financing. Several states, including Michigan, New Jersey, and North Carolina, have established dedicated PFAS remediation funds from settlement proceeds and legislative appropriations.

Q: How should utilities plan for PFAS regulations that may become more stringent over time? A: The current EPA MCLs of 4 ppt for PFOA and PFOS reflect the practical quantitation limit of existing analytical methods, suggesting these values are unlikely to decrease further. However, additional PFAS compounds beyond the current six may be regulated. Utilities should design treatment systems with capacity headroom of 20 to 30% above current needs, modular expansion capability, and the flexibility to add IX polishing downstream of GAC if additional compounds are regulated. Investing in PFAS source identification and elimination upstream of the water supply is equally important, because reducing influent concentrations extends treatment media life and lowers ongoing costs regardless of how regulations evolve.

Q: What is the status of PFAS destruction technologies for spent treatment media? A: High-temperature incineration (at greater than 1,100 degrees Celsius) remains the most widely used destruction method, though EPA research suggests that temperatures above 1,400 degrees Celsius may be needed for complete mineralization. Supercritical water oxidation, commercialized by 374Water and Revive Environmental, operates at 374 degrees Celsius and 220 bar pressure, achieving greater than 99.99% PFAS destruction in laboratory and pilot testing. Electrochemical oxidation (Aclarity, Oxbyel) works at ambient temperature and pressure, making it suitable for on-site deployment. These destruction technologies are currently 2 to 5 times more expensive per unit mass than incineration but are expected to reach cost parity by 2028 as they scale. Utilities should include destruction technology evaluation in their long-term spent media management plans.

Sources

• US Environmental Protection Agency. (2024). PFAS National Primary Drinking Water Regulation: Final Rule. 89 FR 32532. Washington, DC: US EPA.
• American Water Works Association. (2024). PFAS Regulation Compliance Cost Assessment: National Estimates for Public Water Systems. Denver, CO: AWWA.
• Interstate Technology Regulatory Council. (2025). PFAS Technical and Regulatory Guidance: Treatment Technologies. Washington, DC: ITRC.
• City of Stuart, Florida. (2025). PFAS Treatment System: Design, Construction, and First-Year Operational Report. Stuart, FL: City of Stuart Utilities Department.
• Cape Fear Public Utility Authority. (2025). PFAS Treatment Program: Annual Performance and Cost Report 2024. Wilmington, NC: CFPUA.
• Michigan Department of Environment, Great Lakes, and Energy. (2025). PFAS Response: Statewide Monitoring and Treatment Status Update. Lansing, MI: Michigan EGLE.
• Environmental Litigation Journal. (2025). PFAS Litigation Trends: Settlement Analysis and Municipal Claims 2023-2025. Washington, DC: ELJ.
• Water Research Foundation. (2025). Optimizing GAC and IX Treatment for PFAS Compliance: Guidance for Utilities. Alexandria, VA: WRF.