chapter 4: temperature inside the landfill

contains mixed residential and commercial waste at a density of approximately 710 kg/m 3 . Waste
filling in the test area started in 1992 and was completed in 2000 (Jain et al, 2006). Sandy clay
was used as cover soil.
A system of vertical wells was installed to inject leachate, ground water and air to the
bioreactor. A total of 134 injection wells in clusters of three was installed. The total number of
clusters was 45 with most having three wells at different depths of 6.1, 12.2 and 18.3 m (with the
exception of one cluster having two wells). All the injection wells in a cluster are known by the
same designation at the site. The deep injection wells at depths of 18.3 m are referred to as “G”
(Green) in this report, intermediate wells at a depth of 12.2 m as “Y” (Yellow) and the shallow
wells at a depth of 6.1 m as “R” (Red). The bottom three m of the 6-m wells and the bottom six
m of the 12-m and 18-m were screened to allow the passage of liquid and/or air. Type T
thermocouple wires were affixed to the bottom of each injection well to monitor temperature. All
thermocouples were connected to CR-10X data loggers (Campbell Scientific, Logan, UT). A
portion of Cell 1 is permitted to be operated as an aerobic bioreactor therefore air is injected in
the wells in that area only. Data from this area were not used in this study.
To monitor moisture content, temperature and gas quality inside the landfill, a sensor
known as MTG sensor was developed by Gawande et al (2003). These MTG sensors were
installed in clusters placed in rows between injection clusters. To measure in-situ moisture
content, electrical-based and time-domain reflectometry sensors were installed at depths of 4.6
(R), 10.7 (Y) and 16.8 m (G) in monitoring locations. Figure 3-1 provides a detailed schematic of
the well field including the relative locations of the sensors and the injection wells in the
anaerobic portion of the landfill. Figure 3-2 presents a details of an injection and MTG cluster.
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