BACKGROUNDIndustrial odor removers are two-phase flow systems that use effective microorganisms to capture malodor-producing gases from the surroundings. The potency of such systems depends on the interaction of gas with the microorganisms. Therefore, the flow and mass transport properties are key to defining the phenomenon more clearly. RESULTSAn efficient mechanism for mixing the two-phase flow is required to enhance the interaction between the gas and microorganisms. Gas flow must also be controlled to obtain a large residence time in the water basin and facilitate the microorganisms to maximize the usage of malodor-producing gases. One method of improving the gas residence time is by installing baffles in the water basin. However, the installation of baffles also limits the gas concentration distribution in the water basin. Placing a rotating drum in addition to the baffles may overcome the limitations on gas distribution in the water basin. Gas volume fractions, interfacial area per volume, and gas concentration are evaluated to observe the mixing and gas dissolution phenomenon. CONCLUSIONBefore practical implementation, a numerical study on the subject is required for various designs to investigate their effectiveness. Therefore, the present study uses the Euler-Euler numerical scheme to model the gas-liquid flow with mass transport for various designs of water basin. Results show that gas concentration is the most critical parameter in the case of two-phase bubbly flow. (c) 2015 Society of Chemical Industry