VSEP Industries

POTW Discharge

Safeguarding Tomorrow’s Water: Why POTWs will Need to Modernize Wastewater Treatment to Match Today’s Effluent

Across the country, Publicly Owned Treatment Works (POTWs) face a challenge unlike anything imagined when our wastewater systems were first conceived over a century ago. Biological systems were initially designed to treat household sewage and kitchen scraps. Today’s sewage streams carry far more than biodegradable pollutants. They now contain pharmaceuticals, personal care products (PPCPs), PFAS, cleaning products, industrial chemicals, and a growing list of emerging contaminants that traditional treatment processes were never designed to remove. Modern chemistry has outpaced the infrastructure built to protect our waterways.

PFAS and PPCPs simply pass through POTW treatment processes with virtually no change and flow into rivers, lakes, and groundwater, regulators and utilities alike are recognizing the need for a new generation of solutions. These chemical products are persistent and have migrated throughout the environment. This problem represents an enormous challenge that will take years to solve.

Regulators Are Catching Up—But the Data Comes First

The U.S. Environmental Protection Agency (EPA), state regulators, and the scientific community all acknowledge that traditional POTWs were not designed to remove pharmaceuticals (PPCPs), PFAS, or most modern synthetic chemicals. These compounds frequently pass through POTWs untreated and discharge into receiving waters, many of which become downstream drinking water supplies.

The EPA has launched nationwide efforts to better understand PFAS loading at POTWs. In 2024, the agency initiated the POTW Influent PFAS Study, requiring roughly 400 of the nation’s largest treatment plants to complete detailed questionnaires and collect influent and effluent samples. This initiative, currently undergoing federal review, aims to build a robust, national dataset to guide future regulatory action.

EPA’s parallel NPDES PFAS Information Collection Rule (ICR) expands this effort by gathering PFAS data from the largest POTWs. The public comment period has closed, and the EPA intends to finalize the rule by the end of 2025, setting the stage for updated discharge requirements and future effluent limits.

NPDES PFAS Information Collection Rule (ICR)

EPA proposed an NPDES‑linked PFAS ICR in March 2024; public comment is complete. EPA intends to finalize the rule by end of 2025. The ICR would:

  • Collect PFAS data from 400 large POTWs
  • Require sampling from 200‑300 of them
  • Potentially expand to smaller POTWs later

The rule will influence future NPDES permit effluent limits. EPA approved Method 1633 (40 PFAS compounds) in early 2024 and Method 1621. This removed a major regulatory barrier and enabled mandatory sampling.

Quarterly PFAS sampling in new NPDES permits

Some EPA regions (e.g., Region 3 for PA & DE) already began including quarterly PFAS sampling in POTW permits as of 2025. This requires monitoring influent, effluent, and sludge for 40 PFAS compounds for 12 quarters. Some regions are already acting: new NPDES permits for select states now incorporate mandatory quarterly PFAS sampling for influent, effluent, and sludge over a 12‑quarter period.

It’s clear that PFAS monitoring and regulation are rapidly moving from concept to reality. This will eventually require upgrades to existing POTW treatment methods.

Status of EPA Rulemaking and What’s in the Pipeline

Regulatory Action Status
POTW Influent PFAS Study (ICR) Submitted to OMB in Oct 2024; awaiting OMB approval
NPDES PFAS ICR Proposal done; data collection targeted for completion by end of 2025
Information Requests to 400 largest POTWs EPA intends to issue multi‑phase questionnaires under CWA §311

EPA is Considering Future Regulations

EPA may use new PFAS data to:

  • Set PFAS effluent limitations guidelines (ELGs) for certain industries discharging to POTWs.
  • Add PFAS monitoring or limits directly in POTW NPDES permits.
  • Develop sludge/biosolids management rules (currently unregulated for PFAS).

EPA acknowledges PFAS could influence future wastewater criteria similarly to how new PFAS drinking water MCLs (2024) influence water quality‑based effluent limits.

Are new federal rules imminent for PFAS at POTWs?

Yes — PFAS regulation at POTWs is now moving quickly. – Based on EPA actions and industry analysis:

  • Mandatory PFAS sampling for many POTWs is likely to become federal standard.
  • Expanded testing beyond the initial 400 POTWs is expected after data evaluation.
  • States are already integrating PFAS into NPDES permits.
  • National PFAS effluent limits may follow once sufficient data is collected.

EPA is not currently planning to ban biosolids use but continues evaluating contamination risks.

Industrial Dischargers Play a Role—But They’re Not the Whole Story

Industrial facilities have long been contributors of PFAS and other persistent chemicals to sewer systems. EPA’s upcoming rules will require industries connected to POTWs to sample and report PFAS discharges, and pretreatment programs are expected to expand significantly.

But even with strict industrial controls, many PFAS, microplastics, and PPCPs originate in everyday household wastewater, from medications, shampoos, detergents, cosmetics, nonstick products, textiles, and more. These compounds enter sewer systems from millions of homes, beyond the reach of industrial guidelines or pretreatment programs.

That means POTWs will still face PFAS and PPCP contamination, even if industrial controls are tightened. No matter how strong the regulations become, utilities cannot prevent these chemicals from entering the system, they can only treat what arrives.

Rules for PFAS are Clear, but What About PPCPs?

Unlike PFAS, EPA has not yet launched large‑scale rulemaking focused on PPCPs or pharmaceuticals in POTW discharges. However:

  • The EPA has acknowledged that PPCPs and other emerging pollutants are a concern
  • Enhanced monitoring could expand beyond PFAS in future Effluent Guidelines Program Plans.
  • PFAS regulation is often viewed as the template for how emerging contaminants will be handled.

What are the ecological effects of discharging PPCPs and other synthetic chemicals?

  1. Endocrine Disruption – EPA highlights that many PPCPs act as endocrine disruptors, altering hormone levels and leading to reproductive and developmental effects in fish and other aquatic organisms. Effects include: Feminization of male fish, reduced reproductive success, altered growth or development
  2. Chronic, Low‑Dose Toxicity – Many PPCPs show low acute toxicity but cause long‑term reproductive and developmental effects at very low concentrations, often far below limits used for traditional criteria. Because aquatic organisms experience continuous exposure, even trace levels accumulate biological effects over time.
  3. Antibiotic Resistance – EPA reports that certain PPCPs—especially antibiotics—can contribute to antimicrobial resistance, which threatens both aquatic ecosystems and public health.
  4. Behavioral Effects and Survival Impacts – According to EPA summaries and European Commission findings cited by EPA:
  • PPCPs can alter the behavior of fish and wildlife
  • They may impair predator avoidance, feeding, and mating signals
  • These changes can reduce long‑term population survival
  1. Bioaccumulation in Aquatic Food Webs – EPA notes that PPCPs, even at parts‑per‑trillion levels, may bioaccumulate, especially compounds like hormones, fragrances, and lipid‑soluble pharmaceuticals.  This affects: Fish, invertebrates, wildlife that feed on aquatic organisms
  2. Persistent, Ubiquitous Presence – EPA and USGS research show that PPCPs frequently remain in water even after conventional treatment, meaning aquatic organisms are exposed throughout their entire life cycle.
  3. Documented Ecosystem‑Level Harm – EPA’s environmental impact review states that pharmaceuticals entering aquatic systems adversely affect ecosystems, including fish and other species, due to their intrinsic bioactivity and persistence.

EPA’s Position:

  • EPA acknowledges PPCPs as contaminants of emerging concern and recognizes they may impact aquatic life.
  • EPA is actively studying how to update water quality criteria and treatment approaches to account for these chemicals.

The consensus across EPA, USGS, toxicology agencies, and environmental scientists is clear: PPCPs pose real ecological risks, even at trace levels, and current wastewater treatment designs are insufficient to address them.

What does the likely future hold?

  1. Increased Monitoring & Reporting – Expect POTWs nationwide to undergo expanded contaminant monitoring, especially PFAS, biosolids, and industrial sources contributing to the collection system.
  2. NPDES Permits With PFAS Limits – States may adopt water‑quality‑based limits influenced by new drinking water MCLs.
  3. Pretreatment Program Expansion – EPA and states are likely to require industrial users to:
  • Monitor PFAS discharges
  • Substitute or eliminate PFAS where possible
  • Implement BMPs

For many POTWs, the future may include:

  • Advanced adsorption technologies
  • High‑pressure membrane systems (RO, nanofiltration)
  • Enhanced sludge management and PFAS destruction
  • Expanded monitoring of influent, effluent, and biosolids
  • New pretreatment requirements for industrial users

With federal data collection underway and stricter NPDES requirements on the horizon, POTWs nationwide must prepare for a world where emerging contaminants are part of everyday operations.

The Future of POTW Treatment: Emerging Contaminants and the Technologies That Will Define Tomorrow

As the national spotlight intensifies on PFAS, PPCPs, and other emerging pollutants, the role of Publicly Owned Treatment Works is shifting faster than at any time in the last century. Regulators are beginning to take notice, and utilities across the country are preparing for the next generation of treatment requirements. Understanding these technologies is the first step toward designing treatment trains capable of meeting the regulations that are already forming on the horizon.

Adsorption: A First Line of Defense with Important Limits

One of the earliest solutions most POTWs will consider is adsorption—typically through granular activated carbon or ion‑exchange resins. These materials have long been used to polish treated water and are particularly effective at capturing long‑chain PFAS, which cling to carbon surfaces with impressive persistence. For utilities seeking an upgrade that fits within their existing footprint, adsorption feels familiar, manageable, and immediately impactful.

Yet the challenge: short‑chain PFAS do not behave the same way. Their smaller molecular size and higher solubility allow them to pass through carbon far more quickly, often requiring frequent media replacements and driving up operating costs. Adsorption can also only move PFAS from one place to another—it does not destroy them. Spent carbon and resins must eventually be regenerated or incinerated, creating their own downstream waste considerations. For many POTWs, adsorption will be a useful, but incomplete, piece of the future treatment puzzle.

Advanced Oxidation: Ideal for PPCPs, But Not PFAS

Advanced oxidation processes, or AOPs, bring a different kind of power. Using ozone, ultraviolet light, or combinations like UV‑peroxide, AOPs can break apart many pharmaceuticals and personal care products that carbon alone cannot fully remove. These technologies excel at transforming complex organic molecules into simpler, less harmful ones, making them a strong candidate for PPCP reduction.

But PFAS are another story. Their carbon‑fluorine bonds are among the strongest in chemistry, and AOPs simply cannot break them. For utilities seeking a single technology to eliminate all emerging contaminants, oxidation falls short—but as a polishing step for pharmaceuticals and endocrine disruptors, its role is irreplaceable.

Reverse Osmosis: The Most Powerful and Most Demanding Option

If a single technology comes closest to comprehensively removing emerging pollutants, it is spiral‑wound reverse osmosis membranes. RO does what carbon and oxidation cannot: it rejects both long‑chain and short‑chain PFAS with exceptional efficiency. It removes pharmaceuticals, personal care products, microplastics, trace organics, and virtually anything else larger than a water molecule. The water that leaves an RO system is remarkably pure, often suitable for high‑end reuse applications.

But this purity comes at a cost. RO membranes are delicate and require extensive pretreatment to remove suspended solids, scale‑forming minerals, and organic matter. Without the right pretreatment, membranes foul, pressures spike, and operating costs soar. And the very effectiveness of RO introduces a new challenge: it does not destroy PFAS—it concentrates them.

Spiral RO systems produce a large volume of brine, typically 15–30% of the incoming flow, carrying all the captured PFAS and contaminants in a smaller but far more potent stream. For POTWs, this concentrated waste becomes the next problem to solve.

Concentration and Destruction: The Final Step That Will Define PFAS Strategy

No matter which front‑end technology a POTW adopts—adsorption, membranes, flotation, or some combination, PFAS ultimately must be destroyed, not landfilled or diluted. Technologies like thermal oxidation, plasma reactors, and supercritical water oxidation can finally break the carbon‑fluorine bond, permanently eliminating PFAS.

These destruction methods, however, only work efficiently on small, highly concentrated waste streams. That means utilities must first capture PFAS, then concentrate it—usually through RO brine systems or spent adsorbents, and only then destroy it. Treating large volumes directly is economically and operationally impossible. For this reason, nearly every future treatment roadmap includes a concentration step followed by a carefully managed destruction pathway.

The Role of VSEP RO in the Future of PFAS and Concentrate Management

As POTWs look toward the next decade of regulatory change, one truth is becoming increasingly clear: removing PFAS, PPCPs, and other persistent contaminants will require not just capturing them, but managing and destroying their concentrated waste streams. Spiral‑wound RO systems are a powerful tool for removing these pollutants, yet they introduce a new challenge, large volumes of PFAS‑rich concentrate that must be handled responsibly. This is where Vibratory Shear Enhanced Processing (VSEP) RO begins to distinguish itself as either a replacement for spiral RO or a critical partner in a hybrid system.

Unlike traditional spiral‑wound membranes, VSEP operates with a high‑frequency oscillation that continuously shears the membrane surface. This unique feature dramatically reduces fouling and allows the system to process difficult wastewaters with minimal pretreatment, making it easier for POTWs to adopt RO technology in the first place. In many cases, VSEP can act as the primary RO system—offering high recoveries that minimize concentrate volume at the source, shrinking the waste footprint and increasing the feasibility of downstream destruction technologies.

But VSEP’s role becomes even more compelling in plants that already rely on spiral RO. Instead of trying to manage the large reject stream produced by spiral membranes, utilities can turn to VSEP as a volume‑reduction engine, taking the spiral concentrate and squeezing it down to a far smaller, far more manageable volume. This approach moves the PFAS‑laden waste stream into the operational range of modern destruction technologies—thermal, plasma, or supercritical systems—that require highly concentrated feed to be practical and economical.

This hybrid strategy is not theoretical. It was demonstrated and proven in one of the most important concentrate‑management studies ever conducted for municipal wastewater: the landmark CH2M Hill study at Big Bear Valley, California. In this project, seven different concentrate‑disposal technologies were evaluated for their ability to handle RO reject from an advanced water recycling facility. Only one of them—VSEP—was not just modeled on paper, but tested on‑site using real MF/RO pilot concentrate. The results were decisive. The CH2M Hill evaluation found that VSEP effectively reduced the volume of spiral RO reject, producing a high‑quality permeate suitable for blending while meeting land application guidelines. Even more importantly, the study concluded that VSEP was the most cost‑effective concentrate‑management solution when compared with alternatives such as electrodialysis reversal, constructed wetlands, enhanced RO, evaporation systems, and wastewater blending.

This finding carries major implications for POTWs facing the growing challenge of PFAS disposal. As regulatory pressure mounts and destruction technologies become more widespread, utilities will need ways to create feed streams that these destructive processes can actually accept. VSEP offers a path to that future—either as a standalone high‑recovery RO system with minimal pretreatment needs, or as a powerful add‑on that transforms spiral RO concentrate into a volume small enough for practical destruction.

In the journey toward truly eliminating PFAS from the water cycle—not merely transferring them from one place to another—VSEP RO stands out as one of the few technologies capable of closing the loop. Its proven performance at Big Bear Valley is not just a case study; it is a preview of what the next generation of advanced wastewater treatment will require.

Facing the Challenge Together

The presence of PFAS, PPCPs, and other contaminants in both industrial and household wastewater makes one thing clear: the burden of treatment ultimately falls on POTWs. As regulations evolve and scientific understanding grows, the need for advanced, cost‑effective treatment technologies has never been more urgent.

The next era of wastewater management is here—one built around resilience, innovation, and the protection of public health and the environment.

Engineer a More Resilient Water Future

VSEP RO is deployed worldwide for the most demanding reuse applications. As potable reuse expands across the United States—driven by regulatory evolution, water scarcity, and system resilience—VSEP provides the membrane performance required to ensure safe, reliable, and affordable potable water supply.

Ready to evaluate VSEP for your potable reuse project?

Contact our engineering team today to receive a full system assessment, pilot program design, or technical consultation.

info@vsep.com

Learn More:

See Pilot Testing Options: https://www.vsep.com/technology/pilot-testing/

View a VSEP Reclaimed Water Study: https://www.vsep.com/pdf/articles/Big-Bear-RO-Reject-Report.pdf