Removal of per- and polyfluoroalkyl substances (PFAS) from wastewater using the hydrodynamic cavitation on a chip concept

The elimination of micropollutants such as highly fluorinated substances, including per- and polyfluoroalkyl substances (PFAS), in wastewater treatment plants has been receiving growing attention due to the urgent need to minimize their adverse effects on natural water and associated ecosystems. Conventional treatment methods often fall short in effectively removing PFAS. In this study, the Hydrodynamic Cavitation on a Chip concept (HCOC) was utilized to degrade 11 common PFAS variants (PFAS11) for the first time in three different hydrodynamic cavitation reactor set-ups, each enhanced with surface modifications involving roughness elements. Stockholm municipal wastewater treated by a Membrane BioReactor (MBR) process was subjected to fully developed cavitating flow treatment using the three distinct microscale hydrodynamic cavitation (HC) reactors. The obtained results indicate that the chemical-free HCOC technique employed in this study has a significant potential in the degradation of nearly all investigated PFAS11 compounds at a notable rate of 36.1 % while the combination with MBR process can prevent blockage within the fluidic channels, enabling continuous operation with high throughput processing rates. Our proposed methodology demonstrated promising results in eliminating PFAS and could contribute to advancements in the use of microscale HC to treat micropollutants in wastewater. These findings could be a major leap in water treatment technologies addressing the global burden of resource-efficient micropollutant water treatment.