Micro and nanobubbles in water and wastewater treatment: A state-of-the-art review

Air-water micronanobubbles MNBs can be produced by four different methods and be used to improve (1) oxygen transfer in microbiological processes with high consumption rate, (2) algae flotation, (3) decomposition of organic compounds, and (4) fouling mitigation in membranes. The macrobubbles and slugs are currently implemented in the industry, and MNBs are investigated in the labs. The current review maps ways to explore the full potential of MNB flows through basic definitions, state-of-the-art analytical techniques, bubble generation methods, and implementation of engineering principles in water and wastewater treatment processes.