Thermal Degradation of PFAS in Different Scales: Measurement of Hydrogen Fluoride (HF)

Approximately 13% of the waste generated in Germany (2023) is processed in municipal solid waste incinerators (MSWI). MSWI in Europe operate under strict regulatory requirements defined by the Industrial Emissions Directive (IED), resulting in very low overall emissions, including PCDD/F. A more recent and widely discussed group of pollutants are per- and polyfluoroalkyl substances (PFAS), which are thermally degraded to hydrogen fluoride (HF), carbon dioxide (CO2) and other thermodynamic end point compounds depending on elemental composition under complete combustion conditions. This study investigates the completeness of PFAS degradation in laboratory- and pilot-scale incinerators. The conversion of PFAS to HF is assessed using several analytical techniques for detecting fluorine-containing species in flue gas, liquids and solids, and their impact on establishing a consistent fluorine balance (F-balance). Depending on the analytical method employed, the achieved F-balance ranges from 59 to 100 wt% when ‘products of incomplete combustion’ (PICs) are not considered.