Emerging Contaminants Summit
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Emerging Contaminants Summit
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Kristen Thoreson Kristen Thoreson
Director, Research & Development
REGENESIS

Dr. Thoreson leads the chemical research and product development program at REGENESIS. She is trained as a chemist, and her graduate and post-doctorate research focused on mechanistic investigations of chlorinated ethene degradation pathways using molecular models and compound specific isotope analysis (CSIA) for both biotic and abiotic systems. She obtained her BSc in chemistry from the University of Wisconsin – La Crosse, and her PhD in inorganic chemistry from the University of Minnesota. She also spent time as a postdoctoral associate at the Helmholtz Zentrum in Munich, Germany as a part of the Research Unit for Environmental Organic Isotope Chemistry.



WORKSHOP PRESENTATION

Colloidal Activated Carbon for in situ Remediation of PFAS: Performance Review of Multiple Field Studies

With the increasing awareness to the widespread contamination of PFAS coupled with their resistance to degradation, there is a need for low cost strategies to address these contaminants. The ability to implement an in situ barrier of activated carbon to amend the effective foc of an aquifer and increase the natural retardation factor for these contaminants is an appealing strategy to manage these plumes. This risk-based approach sequesters PFAS from the mobile phase and removes the route of exposure to down-gradient receptors. This presentation reviews data from multiple field sites where a single application of colloidal activated carbon has been utilized to address PFAS contamination and co-mingled contaminants. In each case the amendments were applied under low pressure (non-fracking) conditions using direct-push technology or injection wells in a grid or barrier design. Depending on the co-contaminants present, additional remedial agents were also applied to degrade those contaminants. Monitoring at all sites is on-going, with current data ranging from six months to over three years. Results from these field case studies have demonstrated immediate removal of PFAS from the dissolved phase to levels below the US EPA health advisory levels when treated with a single application of colloidal activated carbon. Further questions, including the ability to distribute the colloidal activated carbon in the subsurface, the longevity of the application using predictive model evaluations, the ability to address short chain compounds, and essential design considerations will also be addressed.


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