For decades, per- and polyfluoroalkyl substances, better known as PFAS, have quietly infiltrated nearly every corner of our environment. Often referred to as “forever chemicals” due to their extreme persistence, PFAS are now found in drinking water, food, soil, wildlife, and even human blood. These synthetic compounds have been used in everything from non-stick cookware and stain-resistant fabrics to firefighting foams and industrial processes. But while their commercial utility is undeniable, the health and environmental costs have become impossible to ignore.
PFAS don’t break down naturally in the environment or in the human body. As a result, exposure builds up over time and has been linked to a growing list of health issues, including cancer, immune dysfunction, thyroid disease, and reproductive problems. Recent studies suggest that nearly half of the U.S. population may be exposed to at least one PFAS compound through their tap water alone. And despite growing concern, conventional water treatment systems are not equipped to handle PFAS contamination.
Current PFAS Removal Methods Fall Short
Current approaches to PFAS removal—such as granular activated carbon (GAC) filtration or ion exchange (IX) resins—are useful in capturing these compounds, but not in eliminating them. These technologies effectively transfer PFAS from water into solid waste, such as filter deposits or sludge.
From there, the waste is often incinerated in hopes of destroying the chemicals. However, incineration is far from perfect. Incomplete combustion can result in the release of toxic byproducts or even reintroduce PFAS into the environment through air emissions and contaminated ash.
How Supercritical Water Oxidation Enables PFAS Destruction
The challenge isn't just how to capture PFAS, but how to permanently destroy them—safely and efficiently. One promising avenue gaining attention is Supercritical Water Oxidation (SCWO).
SCWO is an advanced thermal treatment process that operates at extremely high temperatures and pressures—above 374°C and 22.1 megapascals—where water enters a supercritical state. In this unique phase, water becomes neither a gas nor a liquid, but exhibits properties of both. Under these conditions, organic compounds such as PFAS can be thoroughly oxidized, breaking the tough carbon-fluorine bonds that make these substances so difficult to destroy.
Unlike conventional incineration, SCWO doesn’t produce harmful air emissions. It’s also highly efficient, reducing hazardous organic waste. These characteristics make SCWO a compelling option for treating PFAS-contaminated waste streams.
Analytical Techniques in SCWO Research
To better understand the effectiveness of SCWO in PFAS destruction, researchers have developed experimental systems for PFAS treatment scenarios. In a controlled lab environment, PFAS-laden samples are treated in a high-pressure reactor under supercritical conditions. The breakdown process is then monitored using two key analytical techniques: Combustion Ion Chromatography (CIC), which quantifies total fluorine to confirm complete defluorination, and Ultra-Performance Liquid Chromatography with tandem Mass Spectrometry (UPLC-MS/MS), which tracks individual PFAS compounds and identifies any degradation products that may form.
The goal is to not only confirm that PFAS can be destroyed under these conditions but also map out the pathways by which they break down and ensure that no harmful intermediate compounds are produced along the way. Understanding these pathways is critical to ensure that SCWO doesn’t just replace one environmental hazard with another.
Of course, like any emerging technology, SCWO faces challenges. Operating under supercritical conditions requires specialized, corrosion-resistant materials and significant energy input, both of which can increase costs and complicate large-scale deployment. However, as regulatory pressure builds and the public demand for effective PFAS solutions grows, interest in scaling up SCWO and similar methods is increasing.
The Future of PFAS Management
Looking ahead, the future of PFAS management will likely require a combination of technologies: capture methods for widespread low-level contamination, and destruction techniques such as SCWO for high-concentration waste streams. Continued research is also needed to optimize system design, reduce operational costs, and assess long-term reliability and environmental impact.
Ultimately, PFAS represent one of the most complex and persistent environmental challenges of our time. But with the right combination of scientific innovation, regulatory support, and public investment, solutions such as SCWO could offer a way forward, turning the tide against the forever chemicals.