The variety of utilization schemes for the withdrawal of methane-rich refuse decomposition gas is quite large. There is a critical need to tailor the landfill gas withdrawal and processing system to the landfill gas generation rate and the unique marketing constraints which normally apply. Brown and Caldwell is developing methods for determining the most energy-efficient system for collection and utilization of methane-rich decomposition gas from sanitary landfills. The approach involves application of an understanding of the biological processes within the landfill which produce the gas, and the energy utilization factors affecting the ultimate energy product.