Microbubbles, oscillating flow, and mass transfer coefficients in air-water bubble columns

Inna Levitsky, Dorith Tavor, Vitaly Gitis

Research output: Contribution to journalArticlepeer-review


Mass transfer coefficient kLa determines the flux of dissolved oxygen DO in bubble columns. The kLa values can be determined experimentally or predicted using a correlation. Common correlations link kLa with superficial air velocity, air hold-up volume, bubble contact time, bubble rising velocity, or bubble Sauter diameter. We compared experimentally found and predicted kLa values to evidence that none of the above correlations is applicable for microbubbles flow. The only way to accurately predict the flow is by using mass transport models needed to calculate kL. The transition from kL to kLa requires a redefinition of the specific interfacial area a for microbubbles. Microbubbles distribute DO quicker than macrobubbles. Oscillating flow can raise the DO level to saturation. The generation of oscillating flow does not require extra energy turning the subsurface aeration more energy-efficient than the surface aeration.

Original languageAmerican English
Article number103087
JournalJournal of Water Process Engineering
StatePublished - 1 Oct 2022


  • Air sparging
  • Mass transfer coefficient
  • Microbubble
  • Oscillating flow
  • Rising velocity

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Safety, Risk, Reliability and Quality
  • Waste Management and Disposal
  • Process Chemistry and Technology


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