A numerical technique for evaluating the performance of forced convective evaporation system for tannery effluent is presented. The paper describes a mathematical model, which treats the airflow to be two dimensional and liquid flow to be one-dimensional. The turbulence in airflow is modeled with low Reynolds number k-ε model. The interface heat and mass transfer are represented by Reynolds flux model. The governing equations are solved using a modified MAC (Marker and Cell) method. The model is embodied into a computer code, which is applicable to forced convective evaporation system as well as mechanical draft cooling towers of both counter flow and cross flow types. Predicted results compare well with the available data in the literature and with that of experimental data and give closer results than the existing models. Distributions of air velocities, pressure, moisture fraction and air and water temperatures have been presented. The model can be used as design as well as optimization tool. © 2003 Elsevier Ltd. All rights reserved.