Long-term temperature monitoring of geomembranes at dry and wet landfills

Abstract

This paper presents the in situ temperature behavior of geomembrane liners and covers at two different cells in the same municipal solid waste landfill where the liquids management practices differ significantly. One cell is a conventional “dry” landfill where liquids are purposely minimized. The other cell is an anaerobic bioreactor with the waste at a high moisture content, i.e., a “wet” landfill. Thus, we are contrasting geomembrane temperatures in dry versus wet landfills. Furthermore, both the geomembranes beneath the waste and in the final cover above the waste are being monitored. After 10.5-years of monitoring the geomembrane beneath the dry cell, the average temperature was at 20 °C for 5.5 years when it abruptly increased to an average of 30 °C where it has risen slightly since then. For the wet cell, the temperature started at 25 °C and has gradually risen to 41–46 °C over the 3.7-years of monitoring. The temperature monitoring of the geomembranes in the final cover situations (both dry and wet) indicate annual temperature cycling from approximately 0 °C in the winter to 30 °C in the summer. Thus ambient conditions are seen to effect cover geomembrane temperatures while they have no influence on the liner geomembrane temperatures. The paper describes the site conditions, monitoring equipment, gauge installation, and the detailed responses of the four different geomembrane temperature situations. Since the monitoring is ongoing, only tentative conclusions are drawn at this time.