Quantification of PFAS fate in sludge and biosolids handling systems

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Owing to their widespread use in products, per- and polyfluoroalkyl substances (PFAS) have been detected in surface water, groundwater, industrial and municipal wastewaters, sediments and soils. The two most common PFAS, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are emerging groundwater contaminants and pose risks to drinking water resources. As our knowledge about the occurrence, fate, and toxicity of PFOS, PFOA and other PFAS continues to grow, it is likely that the guidelines for these compounds will become increasingly more stringent. The focus of this study is PFAS in sludge handling and biosolids associated with municipal wastewater treatment. Although currently in Canada biosolids are not regulated with respect to PFAS, this situation may change in the future, in light of recently reported cases of PFAS contamination following the application of contaminated biosolids to soil. Information about the occurrence of PFAS in Canadian biosolids is limited and little is known about the transformation and fate of PFAS in sludge handling systems. The overall objective of this project is to investigate the fate of PFAS in sludge handling systems and the potential leaching of PFAS from biosolids. The study will consider the distinct physical and chemical properties of PFAS and the nature of the biosolids produced via different sludge handling technologies as factors that can affect PFAS leaching. The results of the project will provide the participating organizations with information to support decision-making with respect to future sludge handling and biosolids management practices. Insights into the levels of PFAS present in biosolids and the impact of sludge handling practices on them will inform risk analyses and may result in practices and innovative technologies that could be employed in the future to reduce risks.