Quantifying Uncontrolled Landfill Gas Emissions from Two Florida ...

Figure 3-2 Summary of ORS measurements from the 5:00 pm survey of the control cell of
Site #1
The figures show that the prevailing winds were from the southwest during the time of the
measurements. Based on the prevailing wind direction, the southern and western VRPM planes
are located upwind of the actual landfill cell, so flux values measured along these VRPM planes
represent methane emissions from the southern and western slopes of the cell. The VRPM planes
located along the northern and eastern boundaries of the cell are downwind of the landfill cell.
The methane flux values measured during the 4:00 p.m. survey along the northern, eastern,
southern, and western VRPM measurement planes were 3.8, 4.8, 0, and 3.3 grams per second,
respectively (the value of 0 grams per second is used because the methane concentration
measurements from the southern VRPM plane were below the atmospheric background value of
1.7 ppm). The difference between the sum of the fluxes measured along the northern and eastern
planes (8.6 g/s) and the southern and western planes (3.3 g/s), 5.3 grams per second, represents
the calculated methane flux value from the top of the landfill cell (defined as the flat surface area
where instrumentation was deployed). The sum of the flux values measured along the southern
and western planes, 3.3 grams per second, represents the calculated methane flux value from the
southern and western slopes of the landfill cell.
The methane flux values measured during the 5:00 p.m. survey along the northern, eastern,
southern, and western VRPM measurement planes were 2.0, 12, 5.2, and 0.77 grams per second,
respectively. The difference between the sum of the fluxes measured along the northern and
eastern planes (14 g/s) and the southern and western planes (6.0 g/s), 8.0 grams per second,
represents the calculated methane flux value from the top of the landfill cell (defined as the flat
surface area where instrumentation was deployed). The sum of the flux values measured along
the southern and western planes, 6.0 grams per second, represents the calculated methane flux
value from the southern and western slopes of the landfill cell.
As mentioned previously, due to problems with alignment of the OP-TDLAS instrument, data
was collected along only one beam path of the southern VRPM plane. By comparing the
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