"Microbubbles (MBs) are bubbles smaller than one hundredth of a millimetre in diameter, but larger than one micrometre. They have widespread application in industry, medicine, life science, and food technology. Microbubbles may be used for drug delivery, biofilm removal, membrane cleaning /biofilm control and water/wastewater treatment purposes. Also known as micro-nano bubbles (MNBs), these are minute bubbles with diameters on the micrometer and nanometer scale. Along with small size, MNBs have a large specific surface area, high zeta potential, long residence times in water, and high oxygen transfer efficiency. These attributes make MNBs more effective than conventional macro-bubbles in air sparging for groundwater remediation purposes."--