The effects of liquid properties on the hydrodynamics of bubble columns were investigated experimentally through analysis of acoustic sound measurements, using coalescence and non-coalescence mediums. The hydrodynamics parameters such as gas holdup, average bubble radius, gas bubbling rate, root mean square of the sound pressure and damping ratio of the bubble pulsation were investigated at the sparger and bulk regions. The acoustic study revealed that the addition of carboxymethyl cellulose (CMC) and xanthan gum (XG) in small percentage increased the overall gas holdup and reduced the average bubble radius. Moreover, the bubbling rate for these solutions is lower than that for water at low superficial gas velocities. These observations were more apparent in the CMC case. The injection of KCI and silicon polymer substances however, resulted in reduction of the gas holdup and enlargement of the bubble size. In addition, the bubbling rate for the KCI and silicon polymer solutions is found to be superior to that for water. In addition, it is found that acoustic measurements can be used to detect sparger activity for both air-water and non-Newtonian solutions systems. At low superficial gas velocity, the sparger acts as a nozzle, hence heterogeneous bubble size distribution was observed and detected. At high superficial gas velocity, the sparger becomes fully activated and consequently homogeneous size distribution was detected. (c) 2006 Elsevier B.V. All rights reserved.