Quantifying Uncontrolled Landfill Gas Emissions from Two Florida ...

Table 3-7. Calculated methane flux and prevailing wind speed and direction measured
on February 22 along the western VRPM configuration in the bioreactor cell
of Site #1
Time Methane Flux (g/s)
Prevailing Wind Direction
(degrees from North)
Prevailing Wind Speed
(m/s)
11:20:43 0.23 317 3.5
11:27:38 1.4 312 3.5
11:34:36 1.4 311 3.1
11:41:53 0.45 319 2.9
11:48:38 0.56 317 2.8
12:20:43 1.1 314 3.5
12:27:38 0.38 326 3.4
12:34:36 2.8 339 3.5
12:41:53 1.9 337 3.4
12:48:38 0.28 320 2.8
12:56:07 1.1 312 2.6
13:03:26 0.48 318 2.8
13:10:36 1.1 316 3
13:17:42 2.4 310 3.3
13:24:38 2.2 307 3.6
13:57:01 1.5 307 3.3
14:03:38 2.0 301 2.9
14:10:36 3.7 306 3.3
Average= 0.76
Standard Dev.=1.51
3.1.3 Total Site Methane Emissions
Total site methane emissions were estimated using the methane flux results from the VRPM
measurements. The first step in estimating the total methane emissions is to estimate the total
surface area of the control and bioreactor cells, including the surface areas of the corresponding
slopes. This was done using distance measurements taken during the measurement surveys. The
surface area of the slopes was estimated by multiplying the length of the corresponding VRPM
measurement plane by 100 meters, which is the estimated distance from the top of the cell to the
bottom of the landfill mound.
The next step is to calculate methane emission factors for the top area of each cell, and the
corresponding cell slopes. The methane emission factor for the top area of the cell is calculated
by dividing the net methane flux from the top of the cell by the surface area of the cell, and then
converting the value to units of grams per day per meter squared. The following calculation
details how to calculate the methane emission factor for the top of the control area:
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