R is the average annual acceptance rate in megagrams per year. The mass of nondegradable solid waste may be subtracted from the total mass of solid waste in a particular section of the landfill when calculating the value or R, if documentation of the nature and amount of such wastes is maintained.
k is the methane generation rate constant in year-1
t is the age of landfill in years
CNMOC is the concentration of NMOC in parts per million by volume as hexane
c is the time since closure in years. For active landfill c = O and e-kc = 1.
3.6 x 10-9 is a conversion factor
NR 440.75(5)(a)2.2. ‘Tier 1.’ The owner or operator shall compare the calculated NMOC mass emission rate to the standard of 50 megagrams per year and then do one of the following: NR 440.75(5)(a)2.a.a. If the NMOC emission rate calculated in subd. 1. is less than 50 megagrams per year, the landfill owner shall submit an emission rate report as provided in sub. (8) (b) 1., and shall recalculate the NMOC mass emission rate annually as required under sub. (3) (b) 1. NR 440.75(5)(a)2.b.b. If the calculated NMOC emission rate is equal to or greater than 50 megagrams per year, the landfill owner shall either comply with sub. (3) (b) 2., or determine a site-specific NMOC concentration and recalculate the NMOC emission rate using the procedures provided in subd. 3. NR 440.75(5)(a)3.3. ‘Tier 2.’ The landfill owner or operator shall determine the NMOC concentration using the sampling procedures in this subdivision. The landfill owner or operator shall install at least 2 sample probes per hectare of landfill surface that has retained waste for at least 2 years. If the landfill is larger than 25 hectares in area, only 50 sample probes are required. The sample probes shall be located to avoid known areas of nondegradable solid waste. The owner or operator shall collect and analyze one sample of landfill gas from each probe to determine the NMOC concentration using Method 25 or 25C in 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17 (1). Method 18 in 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17 (1), may be used to analyze the samples collected by the Method 25 or 25C sampling procedure. Taking composite samples from different probes into a single cylinder is allowed; however, equal sample volumes shall be taken from each probe. For each composite, the sampling rate, collection times, beginning and ending cylinder vacuums, or alternative volume measurements shall be recorded to verify that composite volumes are equal. Composite sample volumes may not be less than one liter unless evidence can be provided to substantiate the accuracy of smaller volumes. The owner or operator shall terminate compositing before the cylinder approaches ambient pressure, where measurement accuracy diminishes. If using Method 18, the owner or operator shall identify all compounds in the sample and, as a minimum, test for those compounds published in the Compilation of Air Pollutant Emission Factors, AP-42, incorporated by reference in s. NR 440.17 (2) (i) 2., minus carbon monoxide, hydrogen sulfide and mercury. As a minimum, the instrument shall be calibrated for each of the compounds on the list. The concentration of each Method 18 compound shall be converted to CNMOC as hexane by multiplying by the ratio of its carbon atoms divided by 6. If more than the required number of samples are taken, all samples shall be used in the analysis. The landfill owner or operator shall divide the NMOC concentration from Method 25 or 25C by 6 to convert from CNMOC as carbon to CNMOC as hexane. If the landfill has an active or passive gas removal system in place, Method 25 or 25C samples may be collected from these systems instead of surface probes provided the removal system can be shown to provide sampling as representative as the 2 sampling probe per hectare requirement. For active collection systems, samples may be collected from the common header pipe before the gas moving or condensate removal equipment. For these systems, a minimum of 3 samples shall be collected from the header pipe. The landfill owner or operator shall recalculate the NMOC mass emission rate using the equations in subd. 1. and using the average NMOC concentration from the collected samples instead of the default value for the equation provided in subd. 1., and then do one of the following: NR 440.75(5)(a)3.a.a. If the resulting mass emission rate calculated using the site-specific NMOC concentration is equal to or greater than 50 megagrams per year, the landfill owner or operator shall either comply with sub. (3) (b) 2., or determine the site-specific methane generation rate constant and recalculate the NMOC emission rate using the site-specific methane generation rate constant and using the procedure specified in subd. 4. NR 440.75(5)(a)3.b.b. If the resulting NMOC mass emission rate is less than 50 megagrams per year, the owner or operator shall submit a periodic estimate of the emission rate report as provided in sub. (8) (b) 1. and retest the site-specific NMOC concentration every 5 years using the methods specified in this subsection. NR 440.75(5)(a)4.4. ‘Tier 3.’ A landfill owner or operator electing to determine the site-specific methane generation rate constant and to recalculate the NMOC emission rate under this subdivision shall follow the procedures in this subdivision. The site-specific methane generation rate constant shall be determined using the procedures provided in Method 2E in 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17 (1). The landfill owner or operator shall estimate the NMOC mass emission rate using the equations in subd. 1. as appropriate and using a site-specific methane generation rate constant, k, and the site-specific NMOC concentration as determined in subd. 3. instead of the default values provided in subd. 1. The landfill owner or operator shall compare the resulting NMOC mass emission rate to the standard of 50 megagrams per year, and then do one of the following: NR 440.75(5)(a)4.a.a. If the NMOC mass emission rate as calculated using the site-specific methane generation rate constant and concentration of NMOC is equal to or greater than 50 megagrams per year, the owner or operator shall comply with sub. (3) (b) 2. NR 440.75(5)(a)4.b.b. If the NMOC mass emission rate is less than 50 megagrams per year, the owner or operator shall submit a periodic emission rate report as provided in sub. (8) (b) 1. and shall recalculate the NMOC mass emission rate annually, as provided in sub. (8) (b) 1. using the equations in subd. 1. and using the site-specific methane generation rate constant and NMOC concentration obtained in subd. 3. The calculation of the methane generation rate constant is performed only once, and the value obtained from this test shall be used in all subsequent annual NMOC emission rate calculations. NR 440.75(5)(a)5.5. ‘Alternative methods.’ The owner or operator may use other methods to determine the NMOC concentration or a site-specific k as an alternative to the methods required in subds. 3. and 4. if the method has been approved by the administrator. NR 440.75(5)(b)1.1. After the installation of a collection and control system in compliance with sub. (6), the owner or operator shall calculate the NMOC emission rate for purposes of determining when the system can be removed as provided in sub. (3) (b) 3., using the following equation: where:
MNMOC is the mass emission rate of NMOC in megagrams per year
QLFG is the flow rate of landfill gas in cubic meters per minute
CNMOC is the NMOC concentration in parts per million by volume as hexane
NR 440.75(5)(b)2.2. The flow rate of landfill gas, QLFG, shall be determined by measuring the total landfill gas flow rate at the common header pipe that leads to the control device using a gas flow measuring device calibrated according to the provisions of section 4 of Method 2E in 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17 (1). NR 440.75(5)(b)3.3. The average NMOC concentration, CNMOC, shall be determined by collecting and analyzing landfill gas sampled from the common header pipe before the gas moving or condensate removal equipment using the procedures in Method 25C or Method 18 in 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17 (1). If using Method 18, the minimum list of compounds to be tested shall be those published in the most recent Compilation of Air Pollutant Emission Factors, AP-42, incorporated by reference in s. NR 440.17 (2) (i) 2. The sample location on the common header pipe shall be before any condensate removal or other gas refining units. The landfill owner or operator shall divide the NMOC concentration from Method 25C by 6 to convert from CNMOC as carbon to CNMOC as hexane. NR 440.75(5)(b)4.4. The owner or operator may use another method to determine landfill gas flow rate and NMOC concentration if the method has been approved by the department. NR 440.75(5)(c)(c) When calculating emissions for purposes of prevention of significant deterioration, the owner or operator of each MSW landfill subject to the provisions of this section shall estimate the NMOC emission rate for comparison to the major source and significance levels in s. NR 405.02 using the Compilation of Air Pollutant Emission Factors, AP-42, incorporated by reference in s. NR 440.17 (2) (i) 2., or other measurement procedures approved by the department. NR 440.75(5)(d)(d) For the performance test required in sub. (3) (b) 2. c. 2), Method 18, 25 or 25C in 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17 (1), shall be used to determine compliance with the 98% by weight reduction efficiency or the 20 ppmv outlet concentration level, unless another method to demonstrate compliance has been approved by the department as provided by sub. (3) (b) 2. a. 2). Method 3 or 3A, in 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17 (1), shall be used to determine oxygen for correcting the NMOC concentration as hexane to 3%. In cases where the outlet concentration is less than 50 ppm NMOC as carbon (8 ppm NMOC as hexane), Method 25A shall be used in place of Method 25. If Method 18 is used, the minimum list of compounds to be tested shall be those published in the Compilation of Air Pollutant Emission Factors, AP-42, incorporated by reference in s. NR 440.17 (2) (i) 2. The following equation shall be used to calculate efficiency: