Temperature Fluctuations in a Landfill in Response to Periodic Changes in Surface and Tide-Driven Groundwater Temperatures

Abstract

In Australia, the concentration of population along the coastal regions has resulted in the construction of landfills near the coastal regions. The wastes buried in these unlined landfills are therefore exposed to tidal influence, often resulting in the dispersion of organic and inorganic pollutants to the surrounding environment. In a project cosponsored by the Rockhampton Regional Council, a number of processes at a landfill site situated in the flood plains of the Fitzroy River are being investigated. The processes include those in terms of multiphase flow consisting of gas (methane), solute (measured as salts, via EC and pH) and water in a porous media. In this paper we analyse temperature changes in groundwater and porous media of the landfill which is subject to periodic surface and tide-driven temperatures. The heat equation is solved, subject to two periodic boundary conditions (BC): the top BC is a periodic surface temperature due to the change in air temperature, and bottom BC is a periodic function to account for the changes in groundwater temperature induced by tides. The methods can be used to locate key parameters and variables of concern in the porous media, and to forecast their variability with time, using publicly available air temperature and tide data.