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.
NR 440.75(6)(a)1.b.b. For sites with known year-to-year solid waste acceptance rate:
å
=
=
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.
NR 440.75(6)(a)5.5. Owners or operators are not required to expand the system as required in subd. 4. during the first 180 days after gas collection system startup.
NR 440.75(6)(a)6.6. For the purpose of identifying whether excess air infiltration into the landfill is occurring, the owner or operator shall monitor each well monthly for temperature and nitrogen or oxygen as provided in sub. (4) (a) 3. If a well exceeds one of these operating parameters, action shall be initiated to correct the exceedance within 5 calendar days. If correction of the exceedance cannot be achieved 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 exceedance. 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.
NR 440.75(6)(a)7.7. An owner or operator seeking to demonstrate compliance with sub. (3) (b) 2. b. 1) d) through the use of a collection system not conforming to the specifications provided in sub. (10) shall provide information satisfactory to the department as specified in sub. (3) (b) 2. a. 3) demonstrating that off-site migration is being controlled.
NR 440.75(6)(b)(b) For purposes of compliance with sub. (4) (a) 1., each owner or operator of a controlled landfill shall place each well or design component as specified in the approved design plan as provided in sub. (3) (b) 2. a. Each well shall be installed no later than 60 days after the date on which the initial solid waste has been in place for a period of one of the following:
NR 440.75(6)(b)1.1. 5 years if active.
NR 440.75(6)(b)2.2. 2 years if closed or at final grade.
NR 440.75(6)(c)(c) The following procedures shall be used for compliance with the surface methane operational standard as provided in sub. (4) (a) 4.:
NR 440.75(6)(c)1.1. After installation of the collection system, the owner or operator shall monitor surface concentrations of methane along the entire perimeter of the collection area and along a pattern that traverses the landfill at 30 meter intervals, or along a site-specific established spacing, for each collection area on a quarterly basis using an organic vapor analyzer, flame ionization detector, or other portable monitor meeting the specifications provided in par. (d).
NR 440.75(6)(c)2.2. The background concentration shall be determined by moving the probe inlet upwind and downwind outside the boundary of the landfill at a distance of at least 30 meters from the perimeter wells.
NR 440.75(6)(c)3.3. Surface emission monitoring shall be performed in accordance with section 4.3.1 of Method 21 in 40 CFR part 60, Appendix A, incorporated by reference in s. NR 440.17 (1), except that the probe inlet shall be placed within 5 to 10 centimeters of the ground. Monitoring shall be performed during typical meteorological conditions.
NR 440.75(6)(c)4.4. Any reading of 500 parts per million or more above background at any location shall be recorded as a monitored exceedance and the actions specified in this subdivision shall be taken. As long as the specified actions are taken, the exceedance is not a violation of the operational requirements of sub. (4) (a) 4. The actions are as follows:
NR 440.75(6)(c)4.a.a. The location of each monitored exceedance shall be marked and the location recorded.
NR 440.75(6)(c)4.b.b. Cover maintenance or adjustments to the vacuum of the adjacent wells to increase the gas collection in the vicinity of each exceedance shall be made and the location shall be re-monitored within 10 calendar days of detecting the exceedance.