Code of Federal Regulations > Title 40 > Chapter I > Part 98 > Subpart HH > Appendix - Table HH-4 to Subpart HH of Part 98

Regulations last checked for updates: Nov 25, 2024

Title 40 - Protection of Environment last revised: Nov 21, 2024

Appendix - Table HH-4 to Subpart HH of Part 98—Landfill Methane Oxidation Fractions

Link to an amendment published at 89 FR 31941, Apr. 25, 2024.

Under these conditions:	Use this landfill methane oxidation fraction:
I. For all reporting years prior to the 2013 reporting year
C1: For all landfills regardless of cover type or methane flux	0.10
II. For the 2013 reporting year and all subsequent years
C2: For landfills that have a geomembrane (synthetic) cover or other non-soil barrier meeting the definition of final cover with less than 12 inches of cover soil for greater than 50% of the landfill area containing waste	0.0
C3: For landfills that do not meet the conditions in C2 above and for which you elect not to determine methane flux	0.10
C4: For landfills that do not meet the conditions in C2 or C3 above and that do not have final cover, or intermediate or interim cover ^a for greater than 50% of the landfill area containing waste	0.10
C5: For landfills that do not meet the conditions in C2 or C3 above and that have final cover, or intermediate or interim cover ^a for greater than 50% of the landfill area containing waste and for which the methane flux rate ^b is less than 10 grams per square meter per day (g/m ²/d)	0.35
C6: For landfills that do not meet the conditions in C2 or C3 above and that have final cover or intermediate or interim cover ^a for greater than 50% of the landfill area containing waste and for which the methane flux rate ^b is 10 to 70 g/m ²/d	0.25
C7: For landfills that do not meet the conditions in C2 or C3 above and that have final cover or intermediate or interim cover ^a for greater than 50% of the landfill area containing waste and for which the methane flux rate ^b is greater than 70 g/m ²/d	0.10

^a Where a landfill is located in a state that does not have an intermediate or interim cover requirement, the landfill must have soil cover of 12 inches or greater in order to use an oxidation fraction of 0.25 or 0.35.

^b Methane flux rate (in grams per square meter per day; g/m ²/d) is the mass flow rate of methane per unit area at the bottom of the surface soil prior to any oxidation and is calculated as follows:

Where:

MF = Methane flux rate from the landfill in the reporting year (grams per square meter per day, g/m 2/d).

K = unit conversion factor = 10 6/365 (g/metric ton per days/year) or 10 6/366 for a leap year.

SArea = The surface area of the landfill containing waste at the beginning of the reporting year (square meters, m 2).

GCH4 = Modeled methane generation rate in reporting year from Equation HH-1 of this subpart or Equation TT-1 of subpart TT of this part, as applicable, except for application with Equation HH-6 of this subpart (metric tons CH4). For application with Equation HH-6 of this subpart, the greater of the modeled methane generation rate in reporting year from Equation HH-1 of this subpart or Equation TT-1 of this part, as applicable, and the quantity of recovered CH4 from Equation HH-4 of this subpart (metric tons CH4).

CE = Collection efficiency estimated at landfill, taking into account system coverage, operation, and cover system materials from Table HH-3 of this subpart. If area by soil cover type information is not available, use default value of 0.75 (CE4 in table HH-3 of this subpart) for all areas under active influence of the collection system.

N = Number of landfill gas measurement locations (associated with a destruction device or gas sent off-site). If a single monitoring location is used to monitor volumetric flow and CH4 concentration of the recovered gas sent to one or multiple destruction devices, then N = 1.

Rn = Quantity of recovered CH4 from Equation HH-4 of this subpart for the nth measurement location (metric tons).

fRec,n = Fraction of hours the recovery system associated with the nth measurement location was operating (annual operating hours/8760 hours per year or annual operating hours/8784 hours per year for a leap year).

[78 FR 71971, Nov. 29, 2013, as amended at 81 FR 89266, Dec. 9, 2016]

authority: 42 U.S.C. 7401-7671q.

source: 74 FR 56374, Oct. 30, 2009, unless otherwise noted.