Abstract

Landfills or municipal solid waste containment facilities are man-made deposits that have economic value. The study of the landfill after waste placement provides the geologist a unique opportunity to observe sedimentary and post-depositional processes. Waste mass decomposition generates biogas consisting of approximately equal proportions of methane and carbon dioxide. Decomposition of the global waste volume can potentially generate 1.4 × 10¹¹ m³ (5 × 10⁹ ft⁵ or 9.9 × 10⁷ m tons) of methane. A 20-yr composite of landfill biogas generation can contribute 5 × 10¹⁰ m³yr^–1 (1.8 × 10⁹ ft³yr^–1 or 36 × 10⁶ m tons yr^–1) of methane to the global atmospheric budget. The exploitation of landfill gas as an alternative or supplemental energy source is economically viable because large landfills are often associated with highly conurbanized areas that have interminable energy requirements.

Post-disposal processes within the landfill offer the geologist an opportunity to study active geologic and depositional processes. Taphonomic processes that lead to fossilization are operational within the landfill mass. Decomposition and compaction of the waste material can yield a volumetric reduction of > 60%. Volume loss and other processes tend to redistribute material throughout the waste mass. Models of these processes can be used to elucidate the processes leading to the three-dimensional framework and sorting of fossil deposits.