Polyfluoroalkyl substances in dedicated hazardous waste incinerators: Framework and industrial scale experimental estimation of destruction and removal efficiency

Abstract

Per- and polyfluoroalkyl substances (PFAS) are a group of more than 6000 persistent toxic compounds. To prevent negative environmental and health effects, PFAS in waste materials need to be destroyed. Currently, the only treatment that can be expected to reach a PFAS destruction and removal efficiency (DRE) >99.9999% (Basel Convention), is thermal destruction in dedicated hazardous waste incinerators. However, there is little knowledge of thermal PFAS decomposition in industrial scale installations. Therefore, this study quantified the DRE for PFAS regulated by the Stockholm Convention as persistent organic pollutant (POP) of an industrial hazardous waste incinerator. Soil with a POP-PFAS concentration of 107 mg kg DM⁻¹ dominated by perfluorooctane sulphonic acid, N-ethylperfluorooctane sulphonamido acetic acid (N-EtFOSAA) and N-methylperfluorooctane sulphonamido acetic acid (N-MeFOSAA) was fed in the incinerator on top of the baseload. During this spiking, the POP-PFAS concentration in the emitted flue gas only increased from 4.20 (baseload) to 4.27 ng (Nm³)⁻¹. The flue gas fingerprint was dominated by perfluorooctanoic acid. Based on the difference in input and output load, the estimated POP-PFAS DRE was 99.999997 to 99.99996%, indicating that the considered hazardous waste incinerator is apt for POP-PFAS destruction. In spite of recent analytical improvements, an accurate and precise quantitative measurement of PFAS remains challenging due to varying experimental uncertainties and concentrations close to the detection limits.