A unique cyclonic static microbubble flotation column was developed for oily wastewater separation. The separation efficiency was found to be highly dependent on gas holdup and bubble size distribution. By changing the circulation pressure, gas flow rate, frother concentration, the effect of operation parameters on gas holdup and oil removal efficiency were attained. A mathematical modeling between the kinetic constant and the gas holdup was established for oily water separation process. The results show that higher gas holdup and smaller microbubble sizes are beneficial to improve oil removal efficiency.