Quantifying Uncontrolled Landfill Gas Emissions from Two Florida ...

Table 3-41. Total Mercury Concentrations Measured at Site #2 during the October 2007
Field Campaign
Tube # Spike Recovery (%) Conc (µg/m3) Date
1 0.53 10/23/2007
2 0.42 10/23/2007
3 0.11 10/23/2007
CCV 106 Average=0.35
Total mercury concentrations in the landfill gas at Site #2 ranged from 0.11 to 0.53 µg/m 3 , with
an average of 0.35 µg/m 3 for all of the samples. Continuous calibration verification (CCV)
recoveries were 106%.
3.3.2 Gas Sampling Results
Table 3-42 presents the results of the gas composition data collected at Sites #1 and #2 with the
Landtec GEM 2000+ landfill gas monitor. Gas flowrates were measured using an Airfoil pitot
probe with the Shortridge ADM-870 Airdata Multimeter to determine gas velocities.
Table 3-42. Landfill Gas Composition Data Collected at Sites #1 and #2 during the
October 2007 Field Campaign
Site #1 Site #2
Duct Diameter (inches) 11 9
Area (square feet) 0.66 0.44
Gas Velocity (feet/minute) 2880 1679
Gas Flow Rate (CFM) 1901 742
Methane (%) 47.4 36.5
Carbon Dioxide (%) 36.2 34.8
Oxygen (%) 2.6 2.4
N2 Balance (%) 13.7 26.2
Hydrogen Sulfide (ppmv) 83 Invalid Data
Carbon Monoxide (ppmv) 0 to 3 0
Gas sampling results from the landfill gas monitor were consistent with readings taken from
other landfills of similar size and age. The Landtec landfill gas monitor was calibrated using a
gas cylinder containing a mixture of 50-percent methane and 35-percent carbon dioxide in a
balance of nitrogen. The landfill gas monitor has a manufacturer’s specified accuracy of ±3
percent for methane and carbon dioxide, and an accuracy of ±1 percent for oxygen.
A small amount of carbon monoxide was detected at Site #1 possibly due to a small fire present
in the landfill. Carbon monoxide was not detected at Site #2. Hydrogen sulfide was detected at
3-41