LANDFILL GAS TO ENERGY POTENTIAL AT MSW LANDFILLS IN THE US SOUTHEAST: DALTON-WHITFIELD SWM AUTHORITY, A CASE HISTORY

摘要

Municipal solid waste (MSW) landfills receive a variety of residential, commercial and industrial waste that contribute to the overall biodegradable content of the buried waste mass. This waste content is the source of landfill gas production that can either be a nuisance or threat to the public health and to the environment or can be a source of sustainable energy that can be extracted and utilized over the life of the landfill. The methane content of landfill gas (a typical LFG composition being about 50% to 55% methane and 40% to 45% carbon dioxide plus varying amounts of nitrogen, sulfides and trace hydrocarbons) provides the heat energy that may be used to power electrical generating stations or fuel boilers and furnaces. The rate of production of landfill gas (LFG) in a MSW landfill and the quality and continuity of gas production generally depend upon the percentage of biodegradable volatiles in the waste and more specifically, upon the moisture content and age of the waste, the pH of the liquid or leachate that is produced and transported through the waste mass, the compaction density of the waste and the local climate. The value of the extracted LFG primarily lies in its methane content which can be used to power electrical generator stations, to provide a direct heating fuel for boilers, to be conveyed to local natural gas companies (after purification and compression), or to provide a hydrocarbon source for conversion to alternate fuels. In this paper, we look at the impact of these variables on LFG production and generation in southeastern MSW landfills and the potential for recovering and utilizing this LFG for beneficial purposes. This "beneficiation" of recovered LFG is a critical step in developing the methane content of the gas as a sustainable resource, its sustainability being that condition that socially benefits the community, physically enhances our atmosphere and the overall environment in which we live and economically benefits the landfill owner/operator and/or the LFG developer. Economic development of landfill-produced methane is demonstrated through a step-by-step analysis of the potential LFG production of a specific southeastern MSW landfill, the development of the methane gas potential of such a landfill and the rewards associated with such development.