chapter 4: temperature inside the landfill

steady rise in the temperatures. The rate of heating for the all the depths was approximately
5 0 C/year. The rates have been estimated assuming a linear progression from Day 550 to Day
1200. Yesiller and Hanson (2003) reported the rate of increase in temperature in a newly placed
waste (for a landfill cell with leachate recirculation) at around 4 0 C/year.
The effect of leachate injection can also be observed in Figure 4-1. The cooling effect is
demonstrated early during continuous injection between Day 450 and Day 730 and temperature
depression
around Day 500 to 530. The temperature started rising again after 4-6 months due to
enhanced biological activity.
Lastly, the effect of ambient temperature was investigated by attempting to correlate the
ambient temperature for the site. R 2 waste temperature against the
values for temperatures at
deep, middle
and shallow depths were found to be 0.0036, 0.014 and 0.038 respectively. These
R 2 values clearly indicate that there is no relationship between ambient temperature and the
waste temperature. The explanation may be the location of the landfill site in Florida having
moderate temperature range of 13 0 C to 27 0 C. Further, liquid injection appears to more
dominantly control temperature as it initially cools, then leads to heating from biological activity.
To identify temperature events at the injection wells, a value of Y of 20 days and X of
0.5 0 C were used after a certain number of trials. After identifying the significant temperature
drop (t- drop) events, the recorded injection events and the temperature drop events were plotted
together to compare the times as shown in Figures 4-2, 4-3. Looking at these plots, the
coincidence of injection event and t-drop events can be observed.
Looking at the immediate drop in the temperature at the time of injection, 20-day average
of the temperature data does not, at first, seem to be logical. Before trying 20-days average, 4-
days, 8-days and 15-days were tried too but with less agreement with injection records. The
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