Per- and polyfluoroalkyl substances, also known as PFAS, are a broad family of man-made fluorinated chemicals. While their heat-, water-, grease-, and oil-resistant properties¹ have made them essential to various everyday products and industrial processes, many of these compounds are known to have negative effects on human health and the environment. While much toxicological research remains to be done, there is already strong evidence that exposure to some types of these chemicals impacts humans’ thyroid, immune systems, and more². A defining characteristic of PFAS is their carbon-fluorine (C-F) bond; it is one of the strongest in organic chemistry. The C-F bond gives PFAS their unique persistence and makes them resistant to natural degradation pathways³. This persistence, combined with decades of use, has resulted in the widespread accumulation of PFAS in the environment⁴.

Within this broad class of chemicals, PFAS vary in chain length. The length is defined by the number of carbon atoms, ranging from ultra-short (<C3) and short-chain (C4-C7) to long-chain (>C8). Each of these subgroups behaves differently. Among them, short- and ultra-short-chain PFAS pose a distinct challenge for water treatment operators. Their small size, increased mobility, and weak sorption affinity allow them to travel far beyond the original source of contamination and inhibit their removal by conventional water treatment techniques⁵.

Until now, much research and regulatory attention has been given to long-chain PFAS such as Perfluorooctane sulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA). However, short- and ultra-short chain PFAS, in particular Trifluoroacetic acid (TFA), have recently drawn heightened attention as new data reveals high concentrations of TFA in the environment^6,7. As regulatory frameworks expand beyond legacy compounds to include these shorter-chain species, water treatment operators will confront technical limitations. Even as operators seek to remove these compounds from their water streams, many existing treatment systems are not designed to do so efficiently or cost-effectively.

We will present a modular treatment approach designed to address short- and ultra-short-chain PFAS across industrial wastewater and groundwater matrices. The modular treatment approach combines separation and destruction. The destructive step is based on an advanced photochemical reduction in which mediator chemicals are activated by UV light to permanently degrade and defluorinate short- and ultra-short-chain PFAS.

We will present laboratory results demonstrating [...]