A multiphase CFD code was investigated to promote the design and optimization of existent environmental technologies on the decontamination of aqueous streams. First, our case study encompassed the development of the CFD framework to be examined systematically on the prediction of the dynamic behaviour of a pilot trickle-bed reactor (TBR). As long as trickle-bed reactors are determined by the flow environment coupled with chemical kinetics, following the optimization of prominent numerical solution parameters, the theoretical model was validated with experimental data taken from a TBR specifically designed for the catalytic wet oxidation of phenolic wastewaters. Second, several computational runs were carried out at unsteady-state operation to evaluate the dynamic performance addressing the total organic carbon concentration and temperature profiles. CFD computations of total organic carbon conversion were found to agree better with experimental data at lower temperatures. Additionally, the inhomogeneous distribution of gas-liquid was identified through the computational mappings representative of interstitial multiphase flow. The heterogeneous behaviour of liquid phase spatial distribution may be attributed to the local effects near the catalyst particle surface. Finally, gas-liquid channels were associated with different local liquid-catalyst contacting profiles, which indeed affected the organic matter decontamination rates and temperature mappings within the trickle-bed reactor. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.