Quantifying Uncontrolled Landfill Gas Emissions from Two Florida ...

3.2.2.2 February 24
ORS measurements were collected in the bioreactor cell during the morning hours of February
24 using the same configuration used on February 23. Figure 3-7 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.
Figure 3-7 Summary of ORS measurements conducted on Feb. 24 in the bioreactor cell of
Site #2
The figure shows that the prevailing winds were from the southeast during the time of the
measurements. Based on the prevailing wind direction, the southern and eastern 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 eastern slopes of the cell (by convention of
the measurement method, flux values from measurement planes located upwind of the landfill
cell are shown as negative values). The VRPM planes located along the northern and western
boundaries of the cell are downwind of the landfill cell (by convention, flux values from
measurement planes located downwind of the landfill cell are shown as positive values).
The methane flux values measured along the northern, eastern, southern, and western VRPM
measurement planes were 0.35, 0.83, 3.1, and 5.9 grams per second, respectively. The difference
between the sum of the fluxes measured along the northern and western planes (6.3 g/s) and the
southern and eastern planes (3.9 g/s), 2.4 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 eastern planes, 3.9
grams per second, represents the calculated methane flux value from the southern and eastern
slopes of the landfill cell.
Tables 3-28, 3-29, 3-30, and 3-31 present the calculated methane flux, measurement time,
prevailing wind speed, and prevailing wind direction during the time of the VRPM
measurements along the northern, eastern, southern, and western VRPM configurations,
respectively.
3-31