What is PFAS?
Per- and polyfluoroalkyl (PFAS) substances, sometimes referred to as “forever chemicals” due to their environmental persistence, are a category of over 14,000 of man-made chemicals (including PFOS, PFOA, and GenX) with unique water and oil repellant properties widely used in industrial manufacturing and are components of many commonplace products such as fire retardants, nonstick cookware, and consumable packaging.
Where is PFAS found?
PFAS are most commonly found in nonstick products, aqueous film forming foams, packaging, and dozens of other sources. PFAS are persistent and accumulative in the environment, and many water authorities have made their treatment, removal, and destruction a top priority due to the considerable bioaccumulation and health impacts. PFAS are ubiquitous in surface water, groundwater, wastewater treatment (WWT) plants, and drinking water treatment (DWT) plants and have been present in water sources long before society became cognizant of their potential consequences.
How is PFAS treated?
While there are thousands of different PFAS compounds, many share similar properties and can be similarly seperated from water/wastewater. Selection of the preferred treatment option often depends on the site specific PFAS profile, influent loading level, desired effluent targets, and the waste disposal options for the liquid and/or solid wastes generated during treatment. Read more about WaterTectonics PFAS treatment options and important factors we consider in system design here. View a small sampling of our PFAS treatment project case studies here.
PFAS Innovation: Published Works
Dr. Thomas Igou Ph.D. is the Director of Innovation at WaterTectonics. Thomas’ work helps shape the future of water treatment—bridging applied R&D, advanced treatment technologies, and grant-funded innovation. It’s just one of the many reasons we’re so proud to have him leading our innovation efforts at WaterTectonics. Thomas has researched and written several studies and had published papers on the subject of PFAS. Several of those include: “The Minus Approach Can Redefine the Standard of Practice of Drinking Water Treatment” published in Environmental Science & Technology, a biweekly peer-reviewed scientific journal, as well as “Improving the Hydrophobicity of Powder Activated Carbon to Enhance the Adsorption Kinetics of Per- and Polyfluoroalkyl Substances” also in Environmental Science & Technology.
In his published Environmental Science & Technology paper, Dr.Thomas Igou – Director of Innovation at WaterTectonics – touches on several aspects of PFAS and PFAS treatment. “many long-chain and short-chain PFAS can be removed through high-pressure membranes.NF is a superior choice for groundwater and surface water treatment due to its lower energy requirement and superior selectivity compared to those of RO.A great deal of research concerns the creation of “fit-for-purpose” NF membranes, which are modified structurally and/or chemically to provide precise solute separation at the subnanometer or subangstrom scale (e.g., the passage of Ca2+ ions to minimize remineralization needs and scaling propensity while retaining PFAS).” He also states that, “It is very likely that water purveyors will need to adopt Minus Approaches to address contemporary challenges, such as the reduction of the levels of DBPs and KUECs based on their discovery and toxicity, for example, treating PFAS beyond perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) (e.g., more difficult-to-treat short-chain PFAS and PFAS isomers) to increasingly stringent standards with a reasonable cost. It is clear that Plus Approaches do little to control PFAS, and individual states have already begun to adopt standards more stringent than the U.S. Environmental Protection Agency’s currently recommended levels of 70 ppt combined PFOA and PFOS.”
In another of Dr. Thomas Igou’s published papers in Environmental Science & Technology, entitled “Improving the Hydrophobicity of Powder Activated Carbon to Enhance the Adsorption Kinetics of Per- and Polyfluoroalkyl Substances” he covers additional insight into PFAS water treatment, “Per- and polyfluoroalkyl substances (PFAS) are difficult to treat by using conventional drinking water treatment technologies. Herein, we upgrade a commercially available powder activated carbon (PAC) via an acid wash and pyrolysis to amplify hydrophobicity and enhance PFAS adsorption. Minimal differences in overall surface area, micropore volume and area, and external surface area were observed between acid-washed and pyrolyzed PACs. X-ray photoelectron spectroscopy, contact angle measurements, and scanning electron microscopy evidenced ∼5% reduced oxygen content and noticeable hydrophobicity increases for the pyrolyzed PAC, without altering morphology. Adsorption isotherms of perfluorooctanoic acid (PFOA) showed no major increases to adsorption capacity, but more rapid adsorption kinetics of PFOA and perfluorobutanesulfonic acid (PFBS) to the pyrolyzed PAC, in both low and high PFAS concentration tests, were revealed in both reagent water and synthetic natural organic matter, with overall greater removal values (e.g., ∼90% removal vs 60%, in water after 1 h at 2 mg/L PFOA). PFOA and PFBS adsorption behavior adhered to pseudo-second-order kinetics (R2 = 0.843−0.992). Density functional theory calculations quantitatively evaluated adsorption energies of PFOA and PFBS onto a graphene skeleton containing different organic functional groups, finding supportive outcomes. This work greater informs the importance of hydrophobicity for PFAS adsorption onto PAC.”
PFAS Innovation: Submitted and Pending Publication
WaterTectonics’ Director of Innovation, Dr. Thomas Igou PhD, has submitted a paper soon to be accepted by the Process Safety and Environmental Protection Journal. This paper entitled “Per- and Polyfluoroalkyl Substances (PFAS) in Resource Recovery: Transforming Challenges into Opportunities for Sustainable Nutrients and Biosolids Management” was conducted “due to a lack of comprehensive critical review on PFAS in biosolids, as previous review
studies have mainly focused on liquid discharge dynamics. Meanwhile, the United States (U.S.) alone produced 3.8 million dry metric tons of biosolids in 2022, with 56% land-applied as a nutrient source. Therefore, our work is significant and novel, fitting to its up-to-date synthesis of peer-reviewed studies and government reports on PFAS’ impact on wastewater resource recovery facilities (WRRF) nutrients and biosolids circular economy (CE).” In summary “this research addresses critical environmental challenges, offering actionable insights for policymakers, engineers, and researchers to ensure public health, resource management, and global sustainability. Furthermore, this review is pertinent, timely, and appropriate for consideration in this journal, aligning with its scope.”
