Treatments of waste gas as well as solid and liquid wastes are important activities for environmental protection. Thermal oxidation is the most used method for volatile organic compound (VOC) abatement from process off-gases. However, the consumption of natural gas is often considerable, and the running costs of such equipment are very high. This is the main reason why companies are searching for technologies that decrease the consumption of natural gas but still meeting current emission limits. In many cases, thermal oxidation is appropriate to replace catalytic oxidation technology. A mathematical model of an ideal plug-flow packed-bed adiabatic reactor for catalytic oxidation of VOC and carbon monoxide was created to support the design of a catalytic oxidation unit (pilot-plant reactor). Industrial catalyst "EnviCat" based on platinum and palladium applied on the Al2O3 support was used. In the first proposed mathematical model, the maximum working temperature of the catalyst was exceeded. Thus, the catalytic bed had to be divided into two parts. Cooling air was injected between the two catalytic beds. The catalytic oxidation unit (pilot-plant reactor) was designed according to the results of the mathematical model. The experimental data are in good agreement with the results of the mathematical model, although a very simplified model was used.