Influence of Aeration, Introduction of Probiotics, and Supply of Water on Landfill Gas Production—Study of Models

When municipal solid waste (MSW) is placed in a landfill, it undergoes anaerobic decomposition, leading to the production of landfill gas, which primarily consists of methane (CH4) and carbon dioxide (CO2). Reducing methane emissions is essential in the fight against climate change. It must be implemented at global and European levels, as set out in 2030 in the impact assessment of the climate goal plan. This assessment states that to achieve the goal by 2030 and to reduce greenhouse gas emissions by at least 55%, the methane emissions must be reduced, considering the goals of the Paris Agreement. The Glasgow Climate Pact includes a global mitigation target of the year 2030: to reduce CO2 emissions by 45%, and the emissions of methane and other greenhouse gasses. For that purpose, looking for new, more advanced ways of managing such waste is necessary. The main objective of this experimental study was to evaluate the influence of aeration, probiotic introduction, and water supply on the production of landfill gasses (CO2, CH4, N2, H2, etc.) in five different landfill models during the management of MSW and to propose the best solutions for reducing environmental pollution. The results of the research showed that the first and second models of landfills, using only anaerobic conditions, can be used for the treatment of MSW for the production of biogas (CH4, CO2), as up to 40–60% of it was released during the 120-experiment period. The third landfill model can be applied in old, already closed landfills, where the rapid stabilization and aeration of MSW are required to minimize pollutant emissions (N2, etc.) and unwanted odors and shorten biodegradation processes. The results of the fourth and fifth landfill models, in which aerobic–anaerobic conditions were applied, showed that the developing nitrification–denitrification processes resulted in complete nitrogen removal (from 20% to 0%), and overall waste stabilization improved the biodegradation of the MSW. Later, relatively good (on average, 30%) results of biogas (CH4, CO2) emissions are achieved during anaerobic condition formation results. Summarizing all experiment results of all landfill models for the further evaluation of the processes, all models can be applied in real practice depending on where they will be used and what result they want to achieve.