Multiphase flow and mass transfer of non-Newtonian fluid are widely encountered in wastewater treatment equipment. Study of gas-liquid mass transfer in non-Newtonian fluid is essential to achieve optimal design and energy-efficient operation of these equipment. Tap water and carboxyl methyl cellulose (CMC) aqueous solution with different mass fraction were selected to study hydrodynamic and mass transfer characteristics of Newtonian and non-Newtonian fluids in bubbling reactors. The influences of gas superficial velocity and liquid rheological behavior on bubble size distribution

overall gas holdup and volumetric oxygen transfer coefficient were investigated in detail. The results show that characteristic parameters of mass transfer are significantly affected by rheological behavior of liquid phase. In CMC aqueous solutions

bubble equivalent diameters were larger and bubble diameter distributions were broader than those in tap water. Overall gas holdup was increased with superficial gas velocity in both tap water and CMC aqueous solutions

whereas volumetric oxygen transfer coefficient of CMC aqueous solution was smaller than that of tap water. Under the same gas superficial velocity

volumetric oxygen transfer coefficient was decreased when CMC mass fraction in aqueous solution was increased. Based on experimental results

a modified formula of volumetric oxygen transfer coefficient and a dimensionless correlation of oxygen transfer in power-law non-Newtonian fluid were proposed to calculate gas-liquid mass transfer parameters of non-Newtonian fluids in wastewater treatment equipment.