Bubble columns are intensively used as multiphase contactors and reactors in chemical, biochemical and petrochemical industries. They provide several advantages during operation and maintenance such as high heat and mass transfer rates, compactness and low operating and maintenance costs. Three-phase bubble column reactors are widely employed in reaction engineering, i.e. in the presence of a catalyst and in biochemical applications where microorganisms are utilized as solid suspensions in order to manufacture industrially valuable bioproducts. Investigation of design parameters characterizing the operation and transport phenomena of bubble columns have led to better understanding of the hydrodynamic properties, heat and mass transfer mechanisms and flow regime characteristics ongoing during the operation. Moreover, experimental studies are supported with computational fluid dynamics (CFDs) simulations and developed mathematical models to describe better the phenomena taking place in a bubble column reactor.