Spatial variability of waste temperatures in MSW landfills was determined over different physical and temporal scales. Data have been obtained at four landfills located in different climatic regions in North America: Alaska, British Columbia, Michigan, and New Mexico. Temperatures were measured using 100 to over 250 sensors at each site. Data were obtained for 5 to 10 year periods at the sites. Temperatures were measured in wastes with a broad range of ages: newly-placed and old (up to 40-year old). The characteristic shape of waste temperature vs. depth relationships consists of a convex temperature profile with maximum temperatures observed at central locations within the middle third fraction of the depth of the waste mass. Lower temperatures with trends similar to air temperatures were observed above this central zone. Temperatures near the base of the landfills and in the liner systems were relatively steady and elevated above mean annual earth temperature, yet were below the maximum values in the central zones. The location of the maximum temperatures/heat gain is affected in the short term by waste placement temperature and in the long term by heat generation and dissipation. Sustained concave temperature profiles were observed for waste placement in cold temperatures. In British Columbia with high heat generation, temperature increases occurred for multiple years and then dissipated for tens of years. Longer periods of temperature increase were observed at the other sites with relatively lower heat generation rates. Temperatures continue to increase at these sites after approximately a decade since waste placement. The highest temperatures were observed in Michigan followed by British Columbia, New Mexico, and Alaska. The time-averaged waste temperature ranges were 0.9 to 33.0°C, 14.4 to 49.2°C, 14.8 to 55.6°C, and 20.5 to 33.6°C in Alaska, British Columbia, Michigan, and New Mexico, respectively.


Civil and Environmental Engineering



URL: http://digitalcommons.calpoly.edu/cenv_fac/289