Emissions of Selected Greenhouse Gases from a Landfill James L. Hanson1, Alexander H. Sohn2, Nazli Yesiller3, and Derek C. Manheim4 1Professor,
Civil and Environmental Engineering Department, California Polytechnic State University, San Luis Obispo, CA, 93407;
[email protected] 2Graduate Research Assistant, Civil and Environmental Engineering Department, California Polytechnic State University, San Luis Obispo, CA, 93407;
[email protected] 3Director, Global Waste Research Institute, California Polytechnic State University, San Luis Obispo, CA, 93407;
[email protected] 4Graduate Research Assistant, Department of Civil and Environmental Engineering, University of California-Irvine, Irvine, CA, 92697;
[email protected] This investigation was conducted to determine the surface emissions of methane, carbon dioxide, and selected (hydro)chlorofluorocarbons from a landfill (area of 340 acres, volume of waste in place of 22 million yd3) located in northern California. Emissions of methane and carbon dioxide had been studied extensively in previous investigations. However, limited data and analyses are available on emissions of (hydro)chlorofluorocarbons. Chlorinated and fluorinated hydrocarbons commonly are used in refrigeration and insulation foam. The use of CFCs in insulation foams and refrigeration started in early 1930s. After the Montreal Protocol banned the use of CFCs in 1993, CFCs were progressively replaced by HCFCs and HFCs. The most common waste products that emit these chlorinated and fluorinated gases are domestic, commercial, and industrial refrigeration and insulation foams used in appliances or buildings. The most common gases present in these foams, including CFC-11, HCFC-141b, HFC134a, and HFC-245fa, enter landfills due to the disposal of waste foams. CFCs, HCFCs, and HFCs generally do not have significant health effects for humans however, are of primary concern due to their adverse environmental effects. The common CFCs, HCFCs, and HFCs are greenhouse gases that contribute to the depletion of the ozone layer and global climate change. CFCs and HCFCs also are ozone-depleting substances (ODS) due to long atmospheric lifetimes, whereas ozone depletion impacts of the HCFCs are relatively small. A summary of properties and atmospheric impact indicators for the fourteen gases included in the field analysis is provided in Table 1. The gases analyzed had atmospheric lifetimes varying between 1.5 and 190 years. The ozone depleting potential, radiative forcing, and global warming potential ranged from 0 to 1, 0.0003 to 1.66, and 1 to 10,200, respectively. The minimum and maximum CO2 equivalent emissions of the gases analyzed in the test program are presented in Table 2. While the highest emissions were associated with methane and carbon dioxide (on the order of 10+4 Tonnes/year), the emissions of CFC-11 also were high on the order of 10+3 Tonnes/year. The emissions of CFCs were generally higher than those of HCFCs and HFCs, reflecting historical replacement trends of (hydro)chlorofluorocarbons. In addition, the high GWPs for CFCs also contributed
to the high CO2 equivalent emissions of these gases compared to the less environmentally harmful replacements. Table 1 – (Hydro)chlorofluorocarbons Included in the Test Program Chemical
CFC-11 CFC-12 CFC-113 CFC-114 HCFC-21 HCFC-22 HCFC141b HCFC142b HCFC151a
HFC-134a
HFC-152a
HFC-245fa
Carbon Dioxide Methane
Atmospheric Principal Use Lifetime ODP (years) Compounds already phased out under Montreal Protocol Foam blowing agent 45 1 Refrigerant 100 1 Solvent 85 0.8 Propellant 190 1 Compounds currently being phased out under Montreal Protocol Refrigerant blends 1.7 0.04 Refrigerant 11.9 0.055
Radiative Forcing (W/m2)
GWP – 100 years3
0.07 0.17 NA NA
4660 10,200 5820 8590
NA NA
148 1760
Foam blowing agent
9.2
0.11
0.04
782
Foam blowing agent
17.2
0.065
0.003
1980
Refrigerant blends, Foams
NA
0.004
0.003
NA
NA
1120
0.01
138
0.0003
858
Alternatives controlled under Kyoto Protocol Refrigerant blends, foams, fire suppressant, and 13.4 0 propellant in metered-dose inhalers Refrigerant blends, foam blowing agent, and aerosol 1.5 0 propellant Foam blowing agent and possible refrigerant in the 7.7 0 future Principal Landfill Gases -
100
0
1.66
1
-
9.1
0
0.47
28
Table 2 – CO2 Equivalent Emissions of the Test Gases
Compound CFC-11 CFC-12 CFC-113 CFC-114 HCFC-21 HCFC-22 HCFC-141b HCFC-142b HCFC-151a HFC-134a HFC-152a HFC-245fa Total F-Gas Emissions CH4 CO2 Total Surface Emissions (F-Gases + CH4 + CO2)
Surface Emissions (CO2 Eq. Tonnes/year) Minimum % Maximum % 1.01E+03 15.8 3.40E+03 3.0 1.43E+01 0.2 1.88E+02 0.2 2.81E-01 0.0 2.49E+00 0.0 4.18E+00 0.1 4.12E+01 0.0 3.89E-02 0.0 1.59E+02 0.1 2.93E+00 0.0 2.43E+01 0.0 7.64E+00 0.1 6.80E+02 0.6 2.25E+00 0.0 2.24E+01 0.0 N/A N/A N/A N/A 2.89E+01 0.5 1.37E+02 0.1 6.08E-01 0.0 2.55E+01 0.0 9.45E+00 0.1 1.14E+02 0.1 1.08E+03
16.9
4.79E+03
4.3
5.31E+02 4.78E+03
8.3 74.8
8.04E+04 2.65E+04
72.0 23.7
6.39E+03
100.0
1.12E+05
100.0
