A number of important biotrickling filter (BTF) models are reviewed. For our study, a theoretical model, based on H2S removal in a differential BTF under batch mode, was selected among the models reviewed. Using a cascade of BTF units in series, in this work, we have extended the model for continuous operation under dynamic conditions and the model accuracy is verified under a limiting case. The modified model was successfully simulated and used in the performance evaluation of a continuous BTF. Sensitivity analysis of the BTF performance in a continuous operation revealed that liquid-gas velocity ratio (LGVR) has negligible effects as compared to the effects of inlet concentration of H2S and gas velocity. The modified model extends the applicability of the model for full-scale design, process identification and control systems of a BTF in a continuous operation.