NR 440.75(4)(a)2.2. Operate the collection system with negative pressure at each wellhead except under the following conditions: NR 440.75(4)(a)2.a.a. A fire or increased well temperature. The owner or operator shall record instances when positive pressure occurs in efforts to avoid a fire. These records shall be submitted with the annual reports as provided in sub. (8) (f) 1. NR 440.75(4)(a)2.b.b. Use of a geomembrane or synthetic cover. The owner or operator shall develop acceptable pressure limits in the design plan. NR 440.75(4)(a)2.c.c. A decommissioned well. A well may experience a static positive pressure after shut down to accommodate for declining flows. All design changes shall be approved by the department. NR 440.75(4)(a)3.3. Operate each interior wellhead in the collection system with a landfill gas temperature less than 55°C and with either a nitrogen level less than 20% or an oxygen level less than 5%. The owner or operator may establish a higher operating temperature, nitrogen or oxygen value at a particular well. A higher operating value demonstration shall show supporting data that the elevated parameter does not cause fires or significantly inhibit anaerobic decomposition by killing methanogens. Nitrogen and oxygen level shall be determined as follows: 1) The span shall be set so that the regulatory limit is between 20 and 50% of the span.
2) A data recorder is not required.
3) Only 2 calibration gases are required, a zero and span, and ambient air may be used as the span.
4) A calibration error check is not required.
5) The allowable sample bias, zero drift and calibration drift are ± 10%.
NR 440.75(4)(a)4.4. Operate the collection system so that the methane concentration is less than 500 parts per million above background at the surface of the landfill. To determine if this level is exceeded, the owner or operator shall conduct surface testing around the perimeter of the collection area and along a pattern that traverses the landfill at 30 meter intervals and where visual observations indicate elevated concentrations of landfill gas, such as distressed vegetation and cracks or seeps in the cover. The owner or operator may establish an alternative traversing pattern that ensures equivalent coverage. A surface monitoring design plan shall be developed that includes a topographical map with the monitoring route and the rationale for any site-specific deviations from the 30 meter intervals. Areas with steep slopes or other dangerous areas may be excluded from the surface testing. NR 440.75(4)(a)5.5. Operate the system such that all collected gases are vented to a control system designed and operated in compliance with sub. (3) (b) 2. c. In the event the collection or control system is inoperable, the gas mover system shall be shut down and all valves in the collection and control system contributing to venting of the gas to the atmosphere shall be closed within one hour. NR 440.75(4)(a)6.6. Operate the control or treatment system at all times when the collected gas is routed to the system. NR 440.75(4)(b)(b) If monitoring demonstrates that the operational requirements in par. (a) 2., 3. or 4. are not met, corrective action shall be taken as specified in sub. (6) (a) 3. to 5. or (c). If the specified corrective actions are taken, the monitored exceedance is not a violation of the operational requirements in this subsection. NR 440.75(5)(a)1.1. ‘Emission rate calculation.’ The landfill owner or operator shall calculate the NMOC emission rate using either of the equations provided in subd. 1. a. or b. as appropriate. Both equations may be used if the actual year-to-year solid waste acceptance rate is known for part of the life of the landfill and the actual year-to-year solid waste acceptance rate is unknown for part of the life of the landfill. The values used in both equations shall be 0.05 per year for k, 170 cubic meters per megagram for Lo and 4,000 parts per million by volume as hexane for CNMOC. For landfills located in geographical areas with a 30 year annual average precipitation of less than 25 inches, as measured at the nearest representative official meteorologic site, the k value used shall be 0.02 per year. NR 440.75(5)(a)1.a.a. The following equation shall be used if the actual year-to-year solid waste acceptance rate is known: where:
MNMOC is the total NMOC emission rate from the landfill in megagrams per year
k is the methane generation rate constant in year-1
Lo is the methane generation potential in cubic meters per megagram of solid waste
Mi is the mass of solid waste in the ith section in megagrams. 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 for Mi if documentation of the nature and amount of such wastes is maintained.
ti is the age of the ith section in years
CNMOC is the concentration of NMOC in parts per million by volume as hexane
3.6 x 10-9 is a conversion factor
NR 440.75(5)(a)1.b.b. The following equation shall be used if the actual year-to-year solid waste acceptance rate is unknown: where:
MNMOC is the mass emission rate of NMOC in megagrams per year
Lo is the methane generation potential in cubic meters per megagram of solid waste
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: where:
NMOCin is the mass of NMOC entering control device
NMOCout is the mass of NMOC exiting control device
NR 440.75(6)(a)1.1. For the purpose of calculating the maximum expected gas generation flow rate from the landfill to determine compliance with sub. (3) (b) 2. b. 1) a), one of the equations in this subdivision shall be used. The k and Lo kinetic factors 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., or other site specific values demonstrated to be appropriate and approved by the department. If k has been determined as specified in sub. (5) (a) 4., the value of k determined from the test shall be used. A value of no more than 15 years shall be used for the intended use period of the gas mover equipment. The active life of the landfill is the age of the landfill plus the estimated number of years until closure. The equations are as follows: where:
Qm is the maximum expected gas generation flow rate in cubic meters per year
Lo is the methane generation potential in cubic meters per megagram of solid waste
R is the average annual acceptance rate in megagrams per year
k is the methane generation rate constant in year-1
t is the age of the landfill at equipment installation plus the time the owner or operator intends to use the gas mover equipment or active life of the landfill, whichever is less. If the equipment is installed after closure, t is the age of the landfill at installation in years.
C is the time since closure in years. For an active landfill c = 0 and e-kc = 1.
where:
Qm is the maximum expected gas generation flow rate in cubic meters per year
k is the methane generation rate constant in year-1
Lo is the methane generation potential in cubic meters per megagram of solid waste
Mi is the mass of solid waste in the ith section in megagrams
ti is the age of the ith section in years
NR 440.75(6)(a)2.2. If a collection and control system has been installed, actual flow data may be used to project the maximum expected gas generation flow rate instead of, or in conjunction with, the equation in subd. 1. a. or b. If the landfill is still accepting waste, the actual measured flow data will not equal the maximum expected gas generation rate, so calculations using the equation in subd. 1. a. or b. or other methods shall be used to predict the maximum expected gas generation rate over the intended period of use of the gas control system equipment. NR 440.75(6)(a)3.3. For the purposes of determining sufficient density of gas collectors for compliance with sub. (3) (b) 2. b. 1) b), the owner or operator shall design a system of vertical wells, horizontal collectors or other collection devices, satisfactory to the department, capable of controlling and extracting gas from all portions of the landfill sufficient to meet all operational and performance standards. NR 440.75(6)(a)4.4. For the purpose of demonstrating whether the gas collection system flow rate is sufficient to determine compliance with sub. (3) (b) 2. b. 1) c), the owner or operator shall measure gauge pressure in the gas collection header at each individual well, monthly. If a positive pressure exists, action shall be initiated to correct the exceedance within 5 calendar days, except for the 3 conditions allowed under sub. (4) (a) 2. If negative pressure cannot be achieved without excess air infiltration within 15 calendar days of the first measurement, the gas collection system shall be expanded to correct the exceedance within 120 days of the initial measurement of positive pressure. Any attempted corrective measure may not cause exceedances of other operational or performance standards. An alternative timeline for correcting the exceedance may be submitted to the department for approval.
