Progression of Elevated Temperatures in Municipal Solid Waste Landfills

Elevated temperatures in municipal solid waste landfills can pose health, environmental, and safety risks because they can generate excessive gases, liquids, pressures, and heat that can damage landfill infrastructure. This paper discusses mechanisms that can lead to elevated temperatures in the landfill and presents a case history to establish trends in gas composition, leachate collection, settlement, and slope movement. In general, landfill gas composition changes from predominantly methane [50–60% volume-to-volume ratio (v/v)] and carbon dioxide (40–55% v/v) to a composition of carbon dioxide (60–80% v/v), hydrogen (10–35% v/v), and carbon monoxide [>1,500 parts per million per volume (ppmv)] as temperatures elevate. As waste temperatures increase, gas and leachate pressures also increase, resulting in odors, leachate outbreaks, and potential slope instability. These observations are summarized in a progression of elevated temperature indicators that are related to field manifestations and possible remedial measures. Finally, biological and chemical processes are proposed to explain the changes in internal landfill processes.