Due to material and size inhomogeneity as well as to the contents of moisture, ballast and materials producing dangerous emissions in combustion, it is necessary to control composition and the caloric value of waste batches put to combustion furnace. The batches should differ in their important parameters only little and their changes should be slow. The optimization of charge composition guarantees the desirable course of combustion, low fuel consumption, optimum heat utilization and reliable functioning of flue gas cleaning. The paper presents a mathematical model algorithm for incinerator operation. A prerequisite for its application is a database of characteristics of combustible wastes.