Effects of Turbulence on Fine-Bubble Diffuser Performance in Wastewater Aeration Systems

Aeration is an essential and energy intensive process for most wastewater treatment plants, accounting for 45 to 75% of plant energy costs (Reardon, 1995). Higher oxygen transfer efficiency can be achieved by increasing liquid velocity in oxidation ditches using mixers for liquid displacement (Da Silva-Deronzier et al., 1994; Déronzier et al., 1998). Based on mass transfer theory, turbulence at gas-liquid interfaces can promote oxygen transfer and affect aeration efficiency. In this research, the effects of liquid-side turbulence on oxygen transfer were studied in a controlled environment within the range of gas and liquid velocities correspondent to the field. This presentation will include the methodology and results of our experiments as well as a visual investigation of the bubble-liquid interactions.