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The work under the conditions of the micropark experience analyzes the impact of the method of application of mineral wool and various reclamation methods for the physicochemical changes in the soilless track devastated by mining sulfur. Our results showed that the tested waste, as well as its manner of application to the soil, had a positive influence on the physical and chemical properties of degraded soils. The most beneficial impact was recorded in the conditions of association of the mineral wool in the top layer of the soil (0–25 cm) of the sewage sludge.

Mining leads to serious degradation of the ecological values of the landscape. After mining is completed, degraded areas should be reclamated in order to mitigate the destructive effects of mining activities. Effective reclamation aims to initiate soil-forming processes. The paper evaluates the effects of land reclamation in post-mining areas 12 to 14 years after the reclamation process. The assessment was based on a determination of the activity of selected enzymes. Municipal sewage sludge compost (SSC) and compost with a composition of 70% municipal sewage sludge + 30% fly ash (SSFAC) were used as an external source of organic matter in the reclamation. The activity of dehydrogenases, phosphatases, and urease was determined. The fertilization of reclaimed soil with compost caused a significant increase in the activity of the assessed enzymes. Significantly higher dehydrogenase activity was found in the soil treated with SSC. The soil treated with SSFAC was characterized by higher activity of phosphatase and urease. The one-time application of composts from sewage sludge and sludge with fly ash, and the introduction of a mixture of grasses, allow for a permanent reclamation effect. An additional ecological advantage of this reclamation model is waste management, which is part of the circular economy strategy.

The composting of sewage sludge and maize straw mixtures was investigated in this study. The aim was to analyze the influence of different proportions of sewage sludge and maize straw in the mixtures on composting process dynamics (expressed by heat production) and gas emissions. The results showed that all examined mixtures reached a strong thermophilic phase of composting; however, the lowest dynamic of temperature growth was observed in the case of the biggest sewage sludge content (60% of sewage sludge in the composting mixture). The ammonia concentration inside bioreactor chambers was directly related to the content of sewage sludge in the composted mixture. Excessive contents of sewage sludge had a considerable effect on very low C/N ratios and high losses through ammonia emissions. Tests were carried out in reactors with a capacity of 160 dm3 under controlled conditions. All mixtures were aerated by the average air-flow of about 2.5 dm3∙min−1, i.e., the minimum air-flow that allows a temperature of about 70 °C to be reached and a sufficiently long thermophilic phase, which ensures proper composting.

In order to ensure proper composting of sewage sludge it is necessary to use bulking agents which will create favorable water and air conditions inside the pile and will be an additional source of carbon for the improvement of the C: N ratio of a composted mixture. However, the cereal straw widely used for composting of sewage sludge is very expensive and has a negative impact on the economic balance of the operations of a composting plant. Therefore, there is a need for novel, alternative materials that can be used as cheap and effective bulking agents for composting of sewage sludge. The aim of this study was to investigate the composting process of municipal sewage sludge and maize straw as a structural addition. The study was conducted in a specialized bioreactor for modeling aerobic or anaerobic decomposition process of organic materials. The bioreactor was equipped with 165-liter, thermally insulated chambers, controlled air flow and a system of gases and temperature analyzers. The studies have shown that composting of sewage sludge with the addition of maize straw leads to a very intense thermophilic phase resulting in strong emission of CO2. The usage of maize straw allowed to reduce the ammonia emissions and the amount of leachate. The obtained compost had favorable physicochemical and organoleptic properties, i.e. it showed neutral smell of the forest litter, good fragmentation and was not clammy.