Odstranění těžkých kovů z popela splaškových kalů v reaktoru s fluidním ložem

Abstract

This diploma thesis is a part of a joint project of Technical University of Vienna (Austria), ASH DEC Umwelt AG and the city of Vienna. The thesis investigates separation of heavy metals (especially Cu, Cd, Zn, Pb, Ni) from sewage sludge ash. Sewage sludge ash arises by burning sludge from municipal sewage treatment. Sewage sludge contains high amount of compounds, which have a good impact on growth and reproduction of plants (especially the high content of phosphorus). However, it also contains high amount of undesirable compounds which are hazardous for plants and for human health (organic compounds, heavy metals). These undesirable compounds must be removed in order to subsequently use the sewage sludge. In the first step all the organic compounds are removed from the sewage sludge by combustion. An additive based on chlorine and water is added after that. Heavy metals are removed by second combustion process. The aim of the process is to utilize the thermal treatment sewage sludge ash as fertilizer for agricultural purposes. The experiments were carried out in a fluidized bed reactor with a stationary fluid bed and in a rotary reactor. All experiments were performed in the laboratories of the Technical University of Vienna. The theoretical part contains basic information about wastewater, its treatment, fertilizers, formation and treatment of sewage sludge and theoretical description of the main experimental process – fluidization. The experimental section of the thesis describes the devices used during the experiment (fluidized bed reactor and rotary reactor) and the whole process is explained. The effects of key parameters of the experimental procedure (temperature, airflow, residential time and particle size) on process efficiency were investigated and evaluated