Monitoring of biogas production wells in a landfill

Abstract

ABSTARCT: The worldwide energy demand still increases along with civilization development. The energy is prevalently acquired from fossil fuels (coal, oil, natural gas), whose reserves are being slowly used up, or whose utilization has detrimental effect on environment. This is why the renewable energy sources (RES) are gaining an increasing share in energy production, while their utilization will not lead to their scarcity in a long-term perspective, as the resources are renewed in the short-term perspective. Moreover, their negative environmental influence is insignificant. The sun, wind and water, and sometimes geothermal power, are the prevalent sources of renewable energy. Also landfill gas, generated on waste dumps can be utilized as a renewable energy source. Biogas (the landfill gas) is combustible gas belonging to RESs, which is produced from biomass by the process of anaerobic digestion of organic matter. Its main constituents are methane and carbon dioxide. In order to enable utilisation of biogas from landfill, the latter should be equipped with biogas receiving system: the wells together with piping system, which will be responsible for biogas collecting. The methane share in landfill gas varies, depending on contents and composition of organic fraction, but usually it ranges within 40–60%. In order to assist landfill gas production, optimal condition for methane-genesis process should be created within the mass of wastes. Compacting wastes or laying soil layers in-between them can serve as examples. Both processes result in lowering oxygen contents in the wastes. It is, however, the organic fraction content in the landfilled waste that has the greatest impact on biogas production. Following the introduction of waste segregation system, the volume of organic waste landfilled has significantly decreased, thus decreasing the potential of landfills as a source of biogas. The article presents the results of research carried out at an active, municipal waste landfills. The measurements were performed in five degassing wells, located in various parts of the landfill. The research demonstrated that the wells located in the central part of the landfill, which were properly preserved and located within wastes having high organic fraction content, show biogas flow at a good level.