Remediation of groundwater and soil impacted by per- and poly-fluoroalkyl substances using novel modified clays

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The use of and release of aqueous film-forming foams (AFFFs) has led to the detection of elevated levels of per- and polyfluoroalkyl surfactants (PFASs) in many federal and private facilities, such as fire-fighting training sites, fire equipment testing sites, oil refineries, etc. It is a global problem with developed countries registering some of the most polluted sites, impacting soil and water quality. Somes PFAS are persistent, bioaccumulative, and toxic. Driven by the stringent regulations on PFAS, there are urgent needs for cost-effective and efficient treatment technologies for contaminated soil and groundwater. We propose the project, in partnership with CETCO (USA) and Sanexen Environmental Services (Canada), to develop clay-based remediation technologies. We plan to evaluate the performance of the modified clay that was explicitly developed for PFAS. Using laboratory experiments, we plan to identify key environmental factors and sorbent characteristics that affect performance, elucidate the mechanisms of interactions between modified clays and PFASs of various structures and functionalities, and if necessary, suggest solutions to improve the existing commercial products. We expect that by the end of the project, we will be ready to propose and design treatment strategies for a given contaminated site and conduct field trials. We expect that new knowledge developed in the project will improve the understanding of the pros and cons of the new clay products, and potentially, to contribute to future product development. The collaboration among the three parties is geared towards developing new treatment technologies for treating a new category of soil and water pollutants, which is greatly needed for the North America market. As compared with the off-site disposal of contaminated soil, in situ treatment enabled by modified clay has the potential to significantly reduce remediation costs, which will benefit Canada and the USA by reducing the cost of dealing with PFAS contamination in a high number of contaminated sites.