Title : The role of micro-nanobubbles in dissolved air flotation for the removal of micropollutants in drinking water treatment
Abstract:
Dissolved air flotation (DAF) is widely applied for removing suspended particles, fats, oils, grease, and algae in water treatment; however, its effectiveness for dissolved emerging micropollutants remains uncertain. The unique physicochemical properties of micro-nanobubbles, including high surface area, stability, and interfacial charge, suggest potential to enhance adsorption and flotation processes. This study investigated whether micro-nanobubbles can provide a mechanistically meaningful enhancement to conventional DAF for the removal of mixed pharmaceuticals (ibuprofen, furosemide, pristinamycin) and per- polyfluoroalkyl substances (PFAS). Bench-scale experiments were conducted to compare coagulation, conventional DAF, and micro-nanobubble-enhanced flotation under the same contaminated water conditions. At an initial concentration of 5 mg/L for pharmaceuticals and 200 ng/L for PFAS, DAF-based treatments demonstrated measurable removal, with PFOS and pristinamycin reductions of approximately 75% and 80%, depending on treatment configuration, highlighting the complexity of flotation mechanisms for micropollutants. Ongoing work focuses on hybrid nanobubble configurations and testing at lower, more realistic concentrations to better quantify the incremental role of nanobubbles in advanced water treatment, and the results will be presented at the conference.
