Quantifying Uncontrolled Landfill Gas Emissions from Two Florida ...

3.1.2 Bioreactor Cell
3.1.2.1 February 22
ORS measurements were collected in the bioreactor cell during the morning and early afternoon
of February 22. A schematic of the ORS measurement configuration from this cell can be found
in Figure 2-3. Figure 3-3 presents a summary of the actual measurement configurations used in
the cell, as well as the measurement results. The figure depicts the average calculated methane
flux values along each VRPM measurement plane. The blue arrow depicts the prevailing wind
values during the time of the measurements.
The figure shows that the prevailing winds were from the northwest during the time of the
measurements. Based on the prevailing wind direction, the northern and western VRPM planes
are located upwind of the actual landfill cell, and the VRPM planes located along the southern
and eastern boundaries of the cell are downwind of the landfill cell. By convention of the
measurement method, the sum of the flux values from measurement planes located upwind of the
landfill cell is subtracted from the sum of the flux values from the downwind measurement
planes to yield emissions from the cell of interest. Flux values measured along the northern and
western upwind VRPM planes represent methane emissions from the northern and western
slopes of the cell, respectively.
The methane flux values measured along the northern, eastern, southern, and western VRPM
measurement planes were 15, 13, 9.1, and 0.76 grams per second, respectively. The difference
between the sum of the fluxes measured along the southern and eastern planes (22 g/s) and the
northern and western planes (16 g/s), 6.0 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 northern and western planes, 16
grams per second, represents the calculated methane flux value from the northern and western
slopes of the landfill cell.
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