Anaerobic digestion in landfills is brought about by the microbial decomposition of the organic matter in refuse. The levels of organic matter produced per capita vary considerably from developed to developing countries. Worldwide, the urban population is growing at twice the rate of the total population growth, creating unprecedented demands for goods and services as well as increasing pressure on the environment and on safe waste disposal [10]. Landfill-generated gas is on average half methane and half carbon dioxide with energy content from 18 to 19 MJ/m3. Its production does not occur under pressure, and thus recovery pro­cesses must be active. Commercial production of land-gas can also aid with the leaching problems now increasingly associated with landfill sites. Local commu­nities neighboring landfill sites are becoming more aware of the potential for heavy metals and nutrients to leach into aquifers. Landfill processing reduces the volume of sludge to be disposed of, and the nutrient content, thus facilitating proper disposal. Methane is a powerful greenhouse gas, with substantial amounts being derived from unutilized methane production from landfill sites. Its recovery therefore, not only results in the stabilization of the landfill site, allowing faster reuse of the land, but also serves to lessen the impact of biosphere methane emissions on global warming.