Environmental Assessment of Various End-of-Life Pathways for Treating Per- and Polyfluoroalkyl Substances in Spent Fire-Extinguishing Waters.

Per- and polyfluoroalkyl substances (PFAS) are now thought 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 and 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 among the environmental compartments in addition to being toxic. As of now, there is no suitable end-of-life treatment process that is both technologically efficient and cost-effective for the handling of PFAS. Currently, the incineration of the collected extinguishing water at temperatures above 1100 °C is the recommended method for the disposal of PFAS to degrade material compounds. However, this method consumes extensive energy because it requires incineration of large quantities of water to treat a diluted fraction of PFAS. Aside from incineration, adsorption of PFAS on granulated activated carbon is one of the most widely used technologies, albeit with poor adsorption and often requiring very large downstream filtration systems. Finally, the application of functional precipitation agents using commercially available cationic surfactants is a novel approach (PerfluorAd® [Cornelsen] process) that enables the effective precipitation of PFAS from the spent fire-extinguishing waters. Hence, the goal of the present study was to investigate the environmental impacts emanating from the proper treatment of spent fire-extinguishing water with the aforementioned 3 end-of-life treatment scenarios. A life cycle assessment was conducted for this purpose. The results show that the PerfluorAd process outperforms the other 2 treatment technologies across all environmental impact categories except for ozone depletion. Environ Toxicol Chem 2021;40:947-957. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Experimental Study on Fluorine Release from Photovoltaic Backsheet Materials Containing PVF and PVDF during Pyrolysis and Incineration in a Technical Lab-Scale Reactor at Various Temperatures.

With a sharp increase in photovoltaic (PV) installations across the world, PV waste is now a relatively new addition to the e-waste category. From 45,000 tonnes in 2016, the PV waste stream is rapidly increasing and is projected to reach 60 million tonnes by 2050. Backsheets are composite structures made from several material layers of polymer, adhesive, and primer. Widely used PV backsheets can be classified into three core types: (a) KPK (Kynar®/polyethylene terephthalate (PET)/Kynar®), (b) TPT (Tedlar®/PET/Tedlar®), and (c) PPE (PET/PET/ethylvinylacetate). Kynar® and Tedlar® are based on polyvinylidene fluoride (PVDF) and polyvinyl fluoride (PVF), respectively. PPE backsheets are fluorine-free composites made primarily from PET. With increasing focus on the end-of-life (EoL) handling of PV waste, the handling of fluoropolymers, which is largely unexplored, requires closer examination to avoid environmental damage. The aim of this study was to obtain information on the fluorine released from PV backsheet materials into the gas phase during combustion and pyrolysis as EoL pathways. Therefore, several experimental trials were conducted to measure fluorine transfer into the gas phase at 300 °C, 400 °C, 500 °C, and 900 °C (for pyrolysis) and at 750 °C, 850 °C, and 950 °C (for incineration).