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The availability and affordability of fertilizers are the main risks currently faced by the fertilizer market. Therefore, there is a need to look for other sources of nutrient supply for plants, while taking care of soil properties. The application of fertilizers with the addition of functionalized materials could help in the efficient use of nutrients. The aim of the study was to assess the impact of the application of mixtures with the addition of zeolite–vermiculite composites (NaX–Ver) on the culturable microorganisms and selected soil properties. A two-year pot experiment was conducted on soil with elevated contents of cadmium, zinc, and lead. The test treatments included soil mixed with NPK and additives in two doses of NaX–Ver combined with leonardite (Leo) or lignite (L). The test plant used in the experiment was maize. The soil material was analyzed for the number of bacteria, mold fungi, actinomycetes, and ammonifiers. Furthermore, soil pH, EC, N total, and SOC contents, as well as soil respiration activity, were tested. The applied fertilizer mixtures had a great effect on changes in the N total and SOC contents. The N total increase was 45.5% in NaX–Ver3%L3% and 51% in NaX–Ver9%Leo6%, and the largest SOC increase (24.3%) was recorded in the NaX–Ver3%Leo3% treatment. The highest respiration activity was determined in NaX–Ver3%Leo3% and NaX–Ver9%Leo6%: 2.12 µg C-CO2 g−1 DM h−1 and 2.14 µg C-CO2 g−1 DM h−1, respectively. A significant correlation between pH values and the number of culturable microorganisms was found. The number of soil microorganisms depended on the type of fertilization used. The best stimulation of the number of culturable soil microorganisms was found in treatments with the addition of 3% of L or Leo in combination with NaX–Ver. The percentage increases in the number of the analyzed culturable microorganisms after the application of leonardite-based fertilization in combination with the zeolite–vermiculite composite were, on average: bacteria, 1096%; mold fungi, 1529%; actinomycetes, 1477%; ammonifiers, 910%.

Sterilization of municipal waste for a raw material for the production of refuse-derived fuel and to protect surface and ground waters against biological contamination during transfer and storage creates a lot of problems. This paper evaluates the antimicrobial potential of non-equilibrium plasma in relation to the selected groups of microorganisms found in humid waste. The proposed research is to determine whether mixed municipal waste used for the production of alternative fuels can be sterilized effectively using low-temperature plasma generated in a gliding arc discharge reactor in order to prevent water contamination and health risk for working staff. This work assesses whether plasma treatment of raw materials in several process variants effectively eliminates or reduces the number of selected groups of microorganisms living in mixed municipal waste. The presence of vegetative bacteria and endospores, mold fungi, actinobacteria Escherichia coli, and facultative pathogens, i.e., Staphylococcus spp., Salmonella spp., Shigella spp., Enterococcus faecalis and Clostridium perfringens in the tested material was microbiologically analyzed. It was found that the plasma treatment differently contributes to the elimination of various kinds of microorganisms in the analyzed raw materials. The effectiveness of sterilization depended mainly on the time of raw materials contact with low-temperature plasma. The results are very promising and require further research to optimize the proposed hygienization process.

The chemical composition of hop sediments from beer brewing and fermentation gives them the potential for further use. These wastes are not generated in large amounts, but the absence of proper characteristics may lead to processing errors. This study examines the possibility of using hop waste for aerobic biological transformation processes (composting). The study was carried out on two hop sediments from two different technological stages of beer production: hot trub and spent hops. Chemical, microbiological, and biochemical analyses were performed in the composted hop sediments, as was the assessment of phytotoxicity to Lepidium sativum L. The tested feedstocks were partially inhabited by microorganisms and thus safe from an epidemiological point of view, and they were not a source of microbial contamination. Inhibitory properties for plant development were found for hot trub, which most likely result from the organic compound content. If it is only a small portion of its biomass, the mineral composition of hot trub does not exclude the possibility of its composting. Spent hops were characterized by a significant total nitrogen content, which affected the composting process. Composting this sediment required the selection of substrates with a widely C:N ratio.

During the storage of spent polymer materials derived from municipal solid waste, which contain biodegradable impurities, an intense growth of microorganisms takes place. The aerobic metabolism of microorganisms may cause these materials to combust spontaneously and to become a real epidemiological risk for humans. The aim of the research is to determine the optimal addition of calcium oxide (CaO), which effectively reduces the number of selected microorganism groups populating the analyzed materials, in which spent polymers represent a significant fraction: refuse-derived fuel (RDF) and an undersize fraction of municipal solid waste (UFMSW). The main novelty of the experiments is to assess the benefits of using the commonly available and cheap filler (CaO), to hygienize the material and to reduce the fire hazard arising from its storage. During the mixing of spent polymer materials with pulverized CaO (mass shares: 1, 2, and 5% CaO), temperature changes were monitored using thermography. Moisture content (MC), pH, respiration activity (AT4) and bacterial count were determined before and after the experiment. During the addition of CaO (especially when the content was at 5%) to the UFMSW, higher maximum temperatures were obtained than in the case of RDF analyses, which may be the result of a high percentage of the biodegradable fraction and higher MC of the UFMSW. In all cases the waste temperature did not increase again after 3 min. CaO used in the experiment effectively limited the number of microorganisms. The addition of 5% of CaO has showed the strongest antimicrobial properties, and it can be recommended for hygienization of the analyzed materials and for the reduction of the risk of self-heating during their storage in windrows.