Article Highlights• Rectangular photobioreactor containing a porous catalyst was simulated by CFD • Hydrodynamics of the reactor in porous and non-porous zones were studied • Enzymatic photo-degradation of AO7 dye in an aqueous solution was modeled • The CFD simulation was verified using empirical results Abstract A rectangular bioreactor with a porous catalyst (GOx/TiO 2 /PU) was investigated by computational fluid dynamics (CFD). The bioreactor was used for elimination of Acid Orange 7 (AO7) dye as a model aqueous pollutant. CFD simulation was validated experimentally in a flow rate of 30-60 mL/min and initial dye concentration of 5.7-10.75 mg/L. Hydrodynamics equations were successfully integrated to study the effect of porous media on flow behavior and pressure drop. Hydrodynamics and RTD analyses proved that the implementation of polyurethane foam as a porous carrier leads to higher residence time and increases AO7 elimination rate. Comparison of experimental single-pass AO7 elimination results with those of CFD simulations showed an average error of 7.8%, confirming the efficiency of the proposed CFD model.