The implementation of measures and activities aimed at preserving the environment is preceded by the categorization of products created by the application of technological processes. The emission of harmful substances within the limit prescribed values is defined by the valid legislation of the Republic of Serbia. The development of project documentation for the disposal of ash, slag and gypsum from the technological process of flue gas desulphurization (FGD) must be based on the application of modern technologies in order to preserve the surrounding ecosystem. The planning of the landfill space for the accommodation of combustion and desulfurization products requires the analysis of all input parameters of the technological process of electricity production. The use of ash, slag and gypsum as products of the production process of thermal power plants is not adequately accepted in the domestic industry. The role of new technologies should be directed towards the greatest possible utilization of stored products in order to produce new products, thus preserving mineral resources and protecting the conditions of the living environment.