Storage Wars: Sequestering PFAS Using Polymer Chemistry

Speaker: Todd DeJournett, PhD, PE, Senior Engineer, Geosyntec Consultants
Moderator: Craig Benson, PhD, PE, NAE, Professor Emeritus, University of Wisconsin-Madison

Geosyntec, in collaboration with the University of Minnesota, is studying the use of commercially-available polymer flocculants to improve PFAS removal in landfill leachate management operations. Polymer flocculants are water-soluble polymers which cause particles to aggregate, making them easier to filter out of a liquid.

While these polymers have previously been shown to bind PFAS to aquifer solids, like gravel or sand, in groundwater applications, the current research seeks to answer whether or not the polymers can achieve a similar result in landfill leachate. In this approach, the application of polymers, along with solid particles that can be settled from the leachate is proposed to sequester PFAS from leachate in solid materials that can be placed back in the landfill.

Although the complex nature of landfill leachate presents challenges for binding PFAS by the polymers, the team is gaining an understanding of the characteristics of leachate that contribute to these limitations. The team is also evaluating different combinations of polymer and ballast materials to determine if removal of PFAS from landfill leachate via this method can be feasible in a typical solid waste operation.

During this Science Session, DeJournett will cover the following:

1. The conceptual model for this method and its value proposition
2. Some of the technical challenges associated with this method
3. Results available so far and the researchers’ next steps

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Todd DeJournett, PhD, PE
Todd DeJournett is a Senior Engineer at Geosyntec Consultants with over 15 years of experience in industrial and municipal water and wastewater treatment process design. Todd’s practice applies fundamental principles of chemistry and microbiology to minimize client liabilities and maximize their assets. Todd’s experience includes work in the petrochemical, refining, mining, solid waste, and manufacturing sectors. Todd is a frequent collaborator with University of Minnesota faculty through the MNDRIVE program, which encourages the application of innovative University research to problems faced by Minnesota industries.

Craig Benson, PhD, PE, NAE
Craig Benson is former Dean of Engineering at the University of Virginia and Wisconsin Distinguished Professor Emeritus at the University of Wisconsin-Madison. He is an international authority on landfills and waste containment systems. His expertise includes municipal solid waste, hazardous waste, coal combustion residuals, mining and mineral processing wastes, low-level radioactive waste, mixed radioactive waste, uranium mill tailings, and bauxite residuals. Benson was co-Principal Investigator on USEPA’s Alternative Cover Assessment Program (ACAP) and authored the USEPA guidance on water balance covers (aka ET covers). Benson is a Professional Engineer and member of the National Academy of Engineering