Per- and polyfluoroalkyl substances (PFAS) are a suite of man-made chemicals used for a variety of industrial and consumer applications since the 1950s due to their unique chemical properties. PFAS are surfactants used as active ingredients in water-proofing materials (e.g., Goretex) and firefighting foams. PFAS are of concern because of their toxicity and persistence in the environment and the human body. A significant source of PFAS contamination is through the use of aqueous film forming foams (AFFF) used to extinguish chemical fires such as oils, gasoline, or jet fuel. By October 1, 2024, the United States Department of Defense (DoD) is expected to have phased out AFFF from all military installations, accelerating the need for an effective transition from AFFF to F3. The transition from AFFF to F3 poses a significant challenge due to the legacy use of AFFF leaving behind high amounts of residual PFAS in fire suppression systems. Because of the large number of firetrucks in the United States that have been exposed to AFFF and require cleanout, there is a critical need to substantially improve firefighting delivery system cleaning prior to foam transition. Regardless of the rinsing agent, cleanout of firefighting systems is likely to produce a significant amount of PFAS residual waste requiring treatment. Membrane separation technologies have shown to successfully remove a wide range of PFAS with rejection values reportedly above 90%.

The principal objective of this research was to:

1) Develop an effective rinsing procedure for removing AFFF components (i.e., PFAS) from AFFF delivery equipment
2) Perform a demonstration-scale evaluation of ARFF cleanout
3) Utilize high-pressure membrane treatment to concentrate AFFF rinsing residuals.

Several bench scale studies as well as a field demonstration were conducted to evaluate the objectives above. Since ACS 2023, further data and research has been accomplished including a bench scale study, and further data analysis from the field demonstration.

Tzahi Cath

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