Investigating the partitioning behavior of per- and polyfluoroalkyl substances (PFAS) during thermal landfill leachate evaporation.

Thermal landfill leachate evaporator systems can reduce the volume of leachate by up to 97%, while releasing water vapor and producing residuals (volume-reduced leachate and sludge) that are managed on-site. On-site thermal evaporators offer landfill operators leachate management autonomy without being subject to increasingly stringent wastewater treatment plant requirements. However, little is known about the partitioning of PFAS within these systems, nor the extent to which PFAS may be emitted into the environment via vapor. In this study, feed leachate, residual evaporated leachate, sludge, and condensed vapor were sampled at two active full-scale thermal landfill leachate evaporators and from a laboratory-scale leachate evaporation experiment. Samples were analyzed for 91 PFAS via ultra-high pressure liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS). Similar trends were observed from Evaporator 1, Evaporator 2, and the laboratory-scale evaporator; ∑PFAS were concentrated in the residual evaporated leachate during evaporation by a factor of 5.3 to 20. All condensed vapors sampled (n = 5) contained PFAS, predominantly 5:3 fluorotelomer carboxylic acid (5:3FTCA), (full-scale vapors 729 - 4087 ng/L PFAS; lab-scale vapor 61.0 ng/L PFAS). For Evaporators 1 and 2, an estimated 9 - 24% and 10%, respectively, of the PFAS mass entering the evaporators in leachate was released with vapor during the days of sample collection. '.
Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. John A. Bowden reports financial support was provided by Hinkley Center for Solid and Hazardous Waste Management. Timothy G. Townsend reports a relationship with Hinkley Center for Solid and Hazardous Waste Management that includes: employment. Timothy G. Townsend is currently employed as Executive Director of the Hinkley Center for Solid and Hazardous Waste Management. This employment relationship began after funding was awarded for the research in this manuscript, and Timothy G. Townsend was not involved in the grant selection process which funded the work. Timothy G. Townsend’s involvement with the project was limited to manuscript revision and writing feedback. John A. Bowden, corresponding author, was the project principal investigator and primary decision-maker. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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