The thesis has evaluated the impact of the composition of the compost mixture containing sewage sludge, grass and organic fraction of municipal waste, on the effectiveness of the composting process as well as the influence of the obtained composts on the effectiveness of soil phytoremediation. In the first stage, the composting process was carried out and in the second stage of the research, a pot experiment was conducted and the soil supplements were gradually applied, then their influence on the process of degraded soil renourishment was evaluated. During the research, the physical and chemical properties of the soils after the use of resources such as compost and bio-fertilizer gained from the processing of sewage sludge during the process of assisted phytoremediation of highly degraded soil (high content of heavy metals) were assessed. The composting process was carried out in two stages, the first of which lasted for four weeks and was carried out in a closed bioreactor with a flow of added oxygen. The second stage, on the other hand, included so-called ripening. This process lasted for six weeks and it also included the flow of added oxygen. By the end of the process, both mixtures were characterized by high content of nutrients and low content of heavy metals which qualified them to be used in the process of renourishment of degraded soils. The conducted research confirms the possibility of using the obtained composts for fertilization. Moreover, the granulate obtained from the processing of the sewage sludge showed positive influence on the examined soil. All of the supplements increased the increment of the obtained biomass, introducing the missing nutrients into the soil.