Understanding PFAS Engineering Firms: Navigating the Challenges in Water Treatment

Introduction

Few utilities have in-house expertise in PFAS treatment. Most will engage an engineering firm to characterize the problem, evaluate options, design a solution, and support funding applications — decisions that will commit the utility to decades of operating cost. Choosing the right firm, and scoping its work properly, is therefore among the more consequential decisions in a PFAS program. This article covers what these firms do, how to select one, how to structure the engagement, and what should raise concern.

The wider landscape of vendors and specialists is covered in our overview of PFAS technology providers.

The Regulatory Driver

EPA finalized enforceable drinking water limits in April 2024: 4.0 parts per trillion for PFOA and PFOS, with limits for four other PFAS, and compliance required by 2029. In May 2026, EPA proposed retaining the PFOA and PFOS limits with an optional extension to 2031 and rescinding the others; as of September 2026 these remain proposals. Because design through construction typically takes three to five years, most utilities needing treatment are already engaging engineering support.

What PFAS Engineering Firms Do

1. Characterization and Alternatives Analysis

Sampling and interpretation, including the full PFAS profile rather than only regulated compounds, and — critically — an honest evaluation of alternatives to treatment. Source management, blending, alternative supply, interconnection, and point-of-use may be cheaper or faster. A firm that moves straight to treatment design without examining these has skipped the step with the greatest potential savings.

2. Pilot Testing

Designing and running pilot or rapid small-scale column tests on the actual source water, producing the breakthrough data that determines media replacement frequency and therefore long-term operating cost.

3. Design

Process and facility design covering vessels, pretreatment, hydraulics, pumping, electrical and instrumentation, media handling access, and residuals management. Design decisions made here determine operating cost for the life of the asset.

4. Funding Support

Preparing applications for State Revolving Fund programs, federal emerging contaminant funding, and state grants. Many firms have substantial experience here, and it can be among the more valuable parts of the engagement for a small utility.

5. Construction and Commissioning

Bid support, construction administration, startup, and operator training.

6. Ongoing Support

Monitoring interpretation, media change-out planning, and optimization once the system is running.

Selecting a Firm

Qualifications-Based Selection

Engineering services for public agencies are commonly procured on qualifications rather than price, under state equivalents of the federal Brooks Act. Fee is negotiated after the most qualified firm is selected. This structure exists precisely because the cheapest engineering proposal frequently produces the most expensive project.

What to Evaluate

• PFAS-specific experience: Completed PFAS projects, not general water treatment experience. Ask for references from utilities of comparable size.
• Pilot testing capability: Whether they have run pilots and what the full-scale systems designed from them actually achieved.
• Technology neutrality: Whether the firm has designed systems using different technologies, or recommends the same one every time.
• Residuals experience: Whether they have arranged disposal and can speak to current market conditions and costs.
• Funding track record: Applications prepared and funding secured.
• Regulatory relationships: Familiarity with your state primacy agency, which affects how smoothly approvals proceed.
• Staff continuity: Whether the people presented at interview will actually do the work.

Conflicts of Interest

Ask directly whether the firm has financial relationships with equipment or media suppliers. Such relationships are not necessarily disqualifying, but they should be disclosed, and a firm that will benefit from a particular technology selection cannot provide an entirely independent alternatives analysis.

Scoping the Engagement

Phase the Work

Structuring the engagement in phases — characterization and alternatives, then piloting, then design — lets the utility reassess between stages rather than committing to a full design before knowing whether treatment is the right answer.

Specify the Deliverables

An alternatives analysis should include lifecycle costs for each option, not capital cost alone, and should cover residuals management. A pilot report should present breakthrough curves for each PFAS of concern, not a summary removal percentage.

Require Lifecycle Costing

Media replacement and residuals disposal dominate long-term cost and are where optimistic assumptions do the most damage. Ask for sensitivity analysis: what happens if media life is half the estimate, or disposal cost doubles.

What Should Raise Concern

• Proposing advanced oxidation for PFAS removal. Conventional AOP does not destroy PFOA or PFOS and can convert precursors into regulated compounds. A firm proposing it for drinking water compliance does not understand the chemistry.
• Proposing membrane bioreactors or biological treatment. These do not remove PFAS.
• Guaranteed removal percentages without pilot data. Performance depends on site-specific water chemistry, and confident numbers offered before testing should be treated as marketing.
• Skipping the alternatives analysis. Moving directly to treatment design forecloses options that may be substantially cheaper.
• Silence on residuals. A design that does not address what happens to spent media is incomplete.
• Sizing on regulated compounds only. Short-chain compounds usually govern media life.

The Technology Landscape a Good Firm Will Discuss

The proven technologies are granular activated carbon, PFAS-selective anion exchange, and high-pressure membranes. A competent firm will explain the trade-offs candidly: carbon’s lower media cost against its weaker short-chain performance; resin’s longer run times and smaller vessels against higher media cost and single-use disposal; membranes’ consistent performance across chain lengths against energy use and concentrate management.

On emerging technologies — destruction processes such as electrochemical oxidation and supercritical water oxidation — a good firm will be clear that these apply to concentrated residual streams rather than to full treatment flows, and that full-scale operating experience remains limited.

Managing the Relationship

• Stay involved in the alternatives analysis. The utility understands its own operating constraints better than any consultant.
• Ask about operability explicitly. A design that assumes staffing the utility does not have will not perform.
• Get the assumptions in writing, particularly those behind operating cost estimates.
• Keep the data. Characterization and pilot data belong to the utility and will be needed again.

Conclusion

An engineering firm shapes decisions that commit a utility for decades. The selection criteria that matter most are PFAS-specific experience, technology neutrality, willingness to evaluate alternatives to treatment honestly, and competence in residuals and lifecycle costing.

Phasing the engagement, specifying deliverables precisely, and asking directly about supplier relationships all improve the outcome. And a utility that knows enough to recognize the warning signs — advanced oxidation proposed for PFAS removal, guaranteed percentages without pilot data, silence on residuals — is in a far stronger position than one relying entirely on the firm’s judgment.