Biogas production from waste is a subject that is emotionally, but not necessarily,
economically attractive. Methane is the end product of anaerobic digestion of biodegradable
organic matter. Most modern engineered landfills have been designed for biogas
production by undersealing and capping and installing both appropriately designed
wellheads for gas collection and appropriate leachate collection and treatment facilities.
Landfill biogas typically contains between 48% and 56% methane and has, therefore, in its
produced form a calorific value of approximately half that of natural gas, as supplied from
distribution networks. The project life for economic landfill biogas production is typically
10 years, but residual production can be expected to last for more than 40 years. For
economic operation, landfill biogas must, from all but the very largest installations, have a
captive market that does not require gas cleaning and purification. Examples of such