Quantifying Uncontrolled Landfill Gas Emissions from Two Florida ...

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Chapter 4 Conclusion This report provides the results from two field campaigns conducted at two municipal landfill sites in Florida. The field project team collected methane fugitive emissions measurements using two optical remote sensing (ORS) instruments, one scanning GasFinder 2.0 OP-TDLAS instrument (Boreal, Inc.) and one scanning OP-FTIR instrument (IMACC, Inc.). The data was then used with an improved vertical radial plume mapping configuration to calculate net methane flux emission values from the top of each landfill cell, and from the slopes of the cells. Measurements were collected in the bioreactor and control cells at each site (a control cell is defined as an area within the site operated as a conventional landfill, with no leachate or other liquid additions to accelerate waste decomposition). Table 4-1 presents the average calculated methane fluxes from the top and slopes of each landfill cell. Table 4-1. Average Calculated Methane Flux (g/s) Value From Each Landfill Cell Site Survey Area Methane Flux from Top of Landfill Cell Methane Flux from Slopes 1 Site #1 Control Cell (2/20/07, 4:00pm) 5.3 2 3.3 2 (Southern and Western Slopes) Site #1 Control Cell (2/20/07, 5:00pm) 7.6 2 6.0 2 (Southern and Western Slopes) Site #1 Bioreactor Cell (2/22/07) 6.3 16 (Northern and Western Slopes) Site #2 Control Cell (2/24/07) 0 28 (Southern and Eastern Slopes) Site #2 Control Cell (2/25/07) 0 16 (Southern and Eastern Slopes) Site #2 Bioreactor Cell (2/23/07) 5.7 4.4 (Northern and Eastern Slopes) Site #2 Bioreactor Cell (2/24/07) 2.3 3.9 (Northern and Eastern Slopes) 1 The slopes from which the total methane flux values are calculated is dependent upon the prevailing wind direction during the time of the measurements 2 Due to problems with alignment of the OP-TDLAS instrument that prevented collection of a complete dataset, an alternate method was used to calculate the methane flux values from the Site #1 control cell. Therefore, the methane flux values presented from the Site #1 control cell are considered estimated values. Additional information is provided in Section 3. The surveys found that methane emissions from the top of the control and bioreactor cells of Site #1 were comparable. However, methane emissions from the top of the control cell of Site #2 were negligible, while emissions from the top of the bioreactor cell of Site #2 were significant. 4-1
The surveys also found significant methane emissions from the slopes of each landfill cell, especially from the bioreactor cell of Site #1, and the control cell of Site #2. In fact, total methane emissions from the slopes of each cell surveyed during the campaign were more significant than emissions from the top of the landfill cells when considering the much larger surface areas of the slopes compared to the tops of the cells. Overall, total methane emissions from the bioreactor cell of Site #1 were much greater than emissions from the control cell of Site #1, as expected. However, total methane emissions from the bioreactor cell of Site #2 were significantly lower than emissions from the control cell of Site #2. This may be due to the fact that leachate had not been injected into the bioreactor cell at the site in several months due to excessive rainfall. Another factor that may have contributed to the relatively lower emissions from the bioreactor cell of Site #2 was the presence of a fresh soil cover that had been added to the surface of the cell prior to the measurement campaign. Using the data presented in Table 4-1, the calculated total site methane emissions was 5,300 kg/day from Site #1 and 5,600 kg/day for Site #2. For each of the two sites, Summa® canister samples were collected at the gas header pipe upstream of any gas treatment. The header pipe samples were analyzed to provide data on gas composition (methane and carbon dioxide), NMOC, and trace organic constituents including HAPs, H2S, and volatile organic compounds (VOC). Data were also obtained on mercury in the header pipe gas. Data were collected using header pipe gas measurements for total, elemental and organo-mercury (including methyl- and dimethyl-mercury). Table 4-2 presents a summary of the mercury results for both sites from sampling occurring in February and October 2007. Table 4-2. Average Concentrations of Total, Dimethyl, Monomethyl, and Elemental Mercury Measured at Each Site 1 Compound Total Mercury- February 2007 Total Mercury- October 2007 Average Concentration (ng/m 3 ) Site #1 Site #2 Range (ng/m 3 ) Average Concentrati on (ng/m 3 ) Range (ng/m 3 ) 5,022 4,958 to 5,148 43 36 to 47 24,495 21,689 to 25,770 270 109 to 526 2 Dimethyl Mercury 1.91 1.22 to 2.65 5.66 0.69 to 9.19 Monomethyl Mercury 11.8 11.1 to 12.4 0.16 0.06 to 0.31 Elemental Mercury 3,266 3,094 to 3,445 47 22 to 64 1 Total mercury measurements were repeated in the field sampling occurring in October 2007. Organo-mercury and elemental mercury analysis was not repeated. Although there were no observed differences in sampling between field campaigns, there was a difference in analytical methods for total mercury analysis. This is explained in the text supporting this table. 2 Spike recoveries for the dimethyl mercury samples were significantly lower than the QAPP acceptance criteria. During the February 2007 field campaign, total mercury concentrations in the landfill gas at Site #1 ranged from 5,000to 5,200 ng/m 3 with an average of 5,000 ng/m 3 for all of the samples. Spike 4-2
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Quantifying Uncontrolled Landfill G
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Foreword The U.S. Environmental Pro
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3.1.3 Total Site Methane Emissions
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List of Tables Table 1-1. Target Co
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Table 3-28. Calculated Methane Flux
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Table C-6. Methane Concentrations (
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List of Figures Figure 1-1. Map of
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Executive Summary Waste decompositi
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instrument (IMACC, Inc.). Figures 1
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Figure 1-3. Scanning Boreal GasFind
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wind direction data are collected n
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adsorption spectrometer. The analyz
Page 27 and 28: Table 1-2. Schedule of Work Perform
Page 29 and 30: Figure 2-2. Detail of measurement c
Page 31 and 32: corners of the cell, respectively.
Page 33 and 34: 2.2.3 Background Measurements Backg
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Page 37 and 38: was aligned on the mirror targets i
Page 39 and 40: methane concentrations measured alo
Page 41 and 42: Figure 3-3 Summary of ORS measureme
Page 43 and 44: Table 3-5. Calculated methane flux
Page 45 and 46: Table 3-7. Calculated methane flux
Page 47 and 48: cell to the base. The following equ
Page 49 and 50: Table 3-9. Results of TO-15 analysi
Page 51 and 52: Table 3-10. Results of C1 to C6 and
Page 53 and 54: Table 3-14. Monomethyl Mercury Conc
Page 55 and 56: 3.2 Landfill Site #2 3.2.1 Control
Page 57 and 58: Table 3-17. Calculated Methane Flux
Page 63 and 64: 3.2.2 Bioreactor Cell 3.2.2.1 Febru
Page 69 and 70: Based on the calculations presented
Page 71 and 72: Table 3-34. Results for C1 to C6 an
Page 73 and 74: Table 3-38. Monomethyl Mercury Conc
Page 75 and 76: 3.3 Gas and Mercury Sampling Result
Page 77: Site #1 with a level of 83 ppmv. Th
Page 81 and 82: Monomethyl mercury concentrations i
Page 83 and 84: 5.1 Equipment Calibration Chapter 5
Page 85 and 86: The R 2 value was used to assess th
Page 87 and 88: the measured path-integrated methan
Page 89 and 90: 5.2.7 DQI Check of Total Mercury Sa
Page 91 and 92: Site #1 5.4 Site #2 77.9 Completene
Page 95 and 96: U.S. Environmental Protection Agenc
Page 97 and 98: d f e c b PDCs Y X a 2 12( y)( z) (
Page 99 and 100: When the VRPM configuration consist
Page 103 and 104: Table B-3. Distance, and Horizontal
Page 105 and 106: Table B-7. Distance, and Horizontal
Page 107 and 108: APPENDIX C Path-Averaged Methane Co
Page 109 and 110: Table C-3. Methane Concentrations (
Page 117 and 118: Table C-11. Methane Concentrations
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