Removal of Perfluoro-alkyl Substances (PFAS) and Recalcitrant Organic Matter in Landfill Leachate using Coal Fly-Ash

Since the first reported occurrence and impact of PFAS (Perfluoro-alkyl Substances) compounds in 1956 by Stanford university ((Nordby and Luck, 1956), several treatment approaches have been developed and applied in mitigation of these ubiquitous contaminants from the environment. Some of the most effective and conventional treatment methods are activated carbon, membrane filtration, and ion exchange. Most conventional treatment methods for removal of PFAS from concentrated wastewater are Reverse Osmosis (RO) and Granular Activated Carbon (GAC) and can removed more than 90% PFAS (McNamara et al., 2018; Pramanik et al., 2015; Ross et al., 2018; Rostvall et al., 2018; Zhang et al., 2016). However, Reverse Osmosis and Granular Activated Carbon adsorption are not the ultimate disposal techniques and generate PFAS laden secondary contaminant that requires further treatment which is energy consuming and cost intensive. Hence in this study, a more sustainable and cost-effective approach has been studied. Application of Mineral based adsorbents like zeolites, montmorillonite, maize straw-origin ash, chitosan, aminated rice husk, and clay have been analyzed in various studies (He et al., 2006; Johnson et al., 2007; Tang et al., 2010). However, due to low adsorption capacity, mineral adsorbents show lower performance compared activated carbon or ion exchange resins (Zhang et al., 2019). Studies have also proven that physiochemical modification of the adsorbent can improve the PFAS adsorption capacity and henceforth improve the overall PFAS removal. To achieve a sustainable treatment process, Coal-Fly Ash was selected as a novel sorbent for removal of Dissolved Organic Matter and Perfluoro-alkyl Substances (PFAS).