chapter 4: temperature inside the landfill

It is pertinent to discuss fiber optic technique in more detail here because the same
principle is being used in this study. The fiber optic technique can be used to measure
temperature along an optic cable. These landfill temperatures and/or temperature changes are
directly employed to detect liquid leakage through sealing materials, side seeps, and other
abnormal liquid flow. Rapid temperature changes in a small localized area could be an indication
of a region with significant water flow. Alternatively, cable and the waste surrounding the cable
could be heated with a heating cable. The rate of increase in temperature measured by the fiber
optic cable can give an indication of the volumetric water content of the surrounding waste
(Imhoff et al, 2007).
More important is the moisture movement for waste degradation. According to Klink and
Ham (1982), moisture content and movement are separate variables. They observed that methane
production increased 25-50 % when there was moisture flow through the waste as compared to
waste having the same moisture content with no moisture flow. Many researchers have tried
modeling the leachate movement through the landfill. The models describing leachate flow
inside a landfill assume that moisture moves vertically through the landfill as a wetting front
(Reinhart and Townsend, 1998).
Generally the moisture moves inside a landfill as an unsaturated flow except in some
instances such as where leachate ponds on the landfill bottom (Reinhart and Townsend, 1998).
Straub and Lynch (1982) used power law equations to model the unsaturated characteristics of
porous media. Korfiatis et al. (1984) also performed experiments to characterize unsaturated
flow through waste and used the power law defined by Straub and Lynch (1982) to determine
saturation suction head and saturated moisture content. However, Korfiatis et al. (1984) defined
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