Environmental Assessment of Various End-Of-Life Pathways for Treating Per- And Polyfluoroalkyl Substances in Spent Fire-Extinguishing Waters
By Daniel Maga, Venkat Aryan, and Stefano Bruzzano
Environ Toxicol Chem
June 25, 2020
Per- and polyfluoroalkyl substances (PFAS) are now being detected to be far more prevalent in water bodies across the globe than previously reported. In particular, military bases, airports and industrial sites are prone to contamination caused by runoff discharges from fire-extinguishing waters that contain PFAS such as Aqueous Film Forming Foams (AFFF). These substances as well as their metabolites show a high degree of mobility as well as a low biotic and abiotic degradability; as a result, they are bioaccumulative and often migrate between the environmental compartments besides being toxic. As of now, there is no suitable end-of-life treatment process for handling PFAS that is both technologically efficient and cost-effective. Currently, the incineration of the collected extinguishing water at temperatures above 1 100°C is the recommended method for the disposal of PFAS to degrade material compounds. However, this method consumes extensive energy, as it requires incineration of large quantities of water to treat a diluted fraction of PFAS. Besides incineration, adsorption of PFAS on granulated activated carbon is one of the most widely used technology albeit with poor adsorption, often requiring very large downstream filtration systems. Finally, the application of functional precipitation agents using commercially available cationic surfactants is a novel approach (PerfluorAd® process) that enables the effective precipitation of PFAS from the spent fire-extinguishing waters. Hence, the goal of this study was to investigate the environmental impacts emanating from the proper treatment of spent fire-extinguishing water with the aforementioned three end-of-life treatment scenarios. A life cycle assessment was conducted for this purpose. The results show that the PerFluorAd® process outperforms the other two treatment technologies across all environmental impact categories except for ozone depletion.