PROJECT TITLE: Non-Thermal Plasma Degradation of Per- and Polyfluoroalkyl Substances from Landfill Leachate

Project Sponsor: Hinkley Center for Solid and Hazardous Waste Management

Project Duration: Feb. 01, 2021 - Jan. 31, 2022

Project Overview

*Per- and polyfluoroalkyl substances (PFAS) is a group of emerging and persistent contaminants that will likely be regulated in the near future. Conventional processes such as activated carbon adsorption, membrane separation, and ion exchange remove PFAS by separation, thus requiring disposal of the residue. Alternatively, non-thermal plasma processes degrade PFAS by converting PFAS to potentially non-toxic compounds. In preliminary experiments, the PIs demonstrated that in a thin-water-film non-thermal plasma reactor, receiving a continuous flow of deionized water containing a model PFAS (perfluorooctanoic acid, PFOA) at 9 mg/L, the PFOA removal was 81 percent and the defluorination was 23 percent. After switching from deionized water to real-world landfill leachates, the defluorination varied between 8-34%, showing that the PFOA removal highly depended on the leachate components. The energy efficiency of the reactor is approximately two times higher than that of similar technologies in the literature. The tasks of this project are to

1) evaluate the removal of five representative PFAS in addition to PFOA at leachate-relevant PFAS concentrations (µg/L) by the thin-water-film non-thermal plasma reactor.
2) evaluate the effects of leachate components (e.g., inorganic substances, complex organic substances, and simple organic substances) on the removal of one representative PFAS: PFOA. The results will help landfill managers to determine which types of leachate may be treated by the non-thermal plasma reactor.
3) determine the degradation intermediates found in the liquid and gas phases from PFOA. The results will be used to understand the fate of PFOA during the treatment and its degradation mechanisms. They will also help to guide reactor optimization.
4) determine the toxicity of the degradation intermediates of PFOA by an EPA recommended method. *