Virginia Law

A. The provisions of 9VAC5-40-30 (Emission testing) or 40 CFR 60.8, whichever is more restrictive, apply.

B. 1. The owner shall calculate the NMOC emission rate using either the equation provided in subdivision B 1 a of this section or the equation provided in subdivision B 1 b of this section. Both equations may be used if the actual year-to-year solid waste acceptance rate is known, as specified in subdivision B 1 a of this section, for part of the life of the landfill and the actual year-to-year solid waste acceptance rate is unknown, as specified in subdivision B 1 b of this section, for part of the life of the landfill. The values to be used in both equations are 0.05 per year for k, 170 cubic meters per megagram for L₀, and 4,000 parts per million by volume as hexane for the C_NMOC. For landfills located in geographical areas with a 30-year average annual precipitation of less than 25 inches, as measured at the nearest representative official meteorological site, the k value to be used is 0.02 per year.

a. The following equation shall be used if the actual year-to-year solid waste acceptance rate is known.

M_NMOC = 2kL₀M_i (e^-kti) (C_NMOC) (3.6 X 10^-9)

where

M_NMOC = Total NMOC emission rate from the landfill, megagrams per year

k = methane generation rate constant, year^-1

L₀ = methane generation potential, cubic meters per megagram solid waste

M_i = mass of solid waste in the i^th section, megagrams

t_i = age of the i^th section, years

C_NMOC = concentration of NMOC, parts per million by volume as hexane

3.6 X 10^-9 = conversion factor

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 M_i if documentation of the nature and amounts of such wastes is obtained.

b. The following equation shall be used if the actual year-to-year solid waste acceptance rate is unknown.

M_NMOC = 2L₀ R(e^-kc -e^-kt)(C_NMOC)(3.6 X 10^-9)

where

M_NMOC = mass emission rate of NMOC, megagrams per year

L₀ = methane generation potential, cubic meters per megagram solid waste

R = average annual acceptance rate, megagrams per year

k = methane generation rate constant, year^-1

t = age of landfill, years

C_NMOC = concentration of NMOC, parts per million by volume as hexane

c = time since closure, years. For active landfill c = 0 and e^-kc = 1

3.6 X 10^-9 = conversion factor

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 of R if documentation of the nature and amounts of such waste is maintained.

2. Tier 1. The owner shall compare the calculated NMOC mass emission rate to the following emission rate applicability criteria: (i) in the Northern Virginia Volatile Organic Compound Emissions Control Area, 23 megagrams per year or (ii) in the remaining areas of the Commonwealth, 50 megagrams per year.

a. If the NMOC emission rate calculated in subdivision B 1 of this section is (i) 23 megagrams per year in the Northern Virginia Volatile Organic Compound Emissions Control Area or (ii) 50 megagrams per year in the remaining areas of the Commonwealth, then the owner shall submit an emission rate report as provided in 9VAC5-40-5880 D 1, and shall recalculate the NMOC mass emission rate annually as required under 9VAC5-40-5820 C 1.

b. If the calculated NMOC emission rate is greater than or equal to (i) 23 megagrams per year in the Northern Virginia Volatile Organic Compound Emissions Control Area or (ii) 50 megagrams per year in the remaining areas of the Commonwealth, then the owner shall either comply with 9VAC5-40-5820 C 2, or determine a site-specific NMOC concentration and recalculate the NMOC emission rate using the procedures provided in subdivision B 3 of this section.

3. Tier 2. The owner shall determine the NMOC concentration using the following sampling procedure. The owner shall install at least two sample probes per hectare of landfill surface that has retained waste for at least two years. If the landfill is larger than 25 hectares in area, only 50 samples are required. The sample probes should be located to avoid known areas of nondegradable solid waste. The owner shall collect and analyze one sample of landfill gas from each probe to determine the NMOC concentration using Reference Method 25C of Appendix A of 40 CFR Part 60 or Reference Method 18 of Appendix A of 40 CFR Part 60. If using Reference Method 18 of Appendix A of 40 CFR Part 60, the minimum list of compounds to be tested shall be those published in the "Compilation of Air Pollutant Emission Factors (AP-42)" (see 9VAC5-20-21). If composite sampling is used, equal volumes shall be taken from each sample probe. If more than the required number of samples are taken, all samples shall be used in the analysis. The owner shall divide the NMOC concentration from Reference Method 25C of Appendix A of 40 CFR Part 60 by six to convert from C_NMOC as carbon to C_NMOC as hexane.

a. The owner shall recalculate the NMOC mass emission rate using the equations provided in subdivision B 1 a or B 1 b of this section and using the average NMOC concentration from the collected samples instead of the default value in the equation provided in subdivision B 1 of this section.

b. If the resulting mass emission rate calculated using the site-specific NMOC concentration is greater than or equal to (i) 23 megagrams per year in the Northern Virginia Volatile Organic Compound Emissions Control Area or (ii) 50 megagrams per year in the remaining areas of the Commonwealth, then the owner shall either comply with 9VAC5-40-5820 C 2, or determine the site-specific methane generation rate constant and recalculate the NMOC emission rate using the site-specific methane generation rate using the procedure specified in subdivision B 4 of this section.

c. If the resulting NMOC mass emission rate is less than (i) 23 megagrams per year in the Northern Virginia Volatile Organic Compound Emissions Control Area or (ii) 50 megagrams per year in the remaining areas of the Commonwealth, the owner shall submit a periodic estimate of the emission rate report as provided in 9VAC5-40-5880 D 1 and retest the site-specific NMOC concentration every five years using the methods specified in this section.

4. Tier 3. The site-specific methane generation rate constant shall be determined using the procedures provided in Reference Method 2E of Appendix A of 40 CFR Part 60. The owner shall estimate the NMOC mass emission rate using equations in subdivision B 1 a or B 1 b of this section and using a site-specific methane generation rate constant k, and the site-specific NMOC concentration as determined in subdivision B 3 of this section instead of the default values provided in subdivision B 1 of this section. The owner shall compare the resulting NMOC mass emission rate to the following emission rate applicability criteria: (i) in the Northern Virginia Volatile Organic Compound Emissions Control Area, 23 megagrams per year or (ii) in the remaining areas of the Commonwealth, 50 megagrams per year.

a. If the NMOC mass emission rate as calculated using the site-specific methane generation rate and concentration of NMOC is greater than or equal to (i) 23 megagrams per year in the Northern Virginia Volatile Organic Compound Emissions Control Area or (ii) 50 megagrams per year in the remaining areas of the Commonwealth, the owner shall comply with 9VAC5-40-5820 C 2.

b. If the NMOC mass emission rate is less than (i) 23 megagrams per year in the Northern Virginia Volatile Organic Compound Emissions Control Area or (ii) 50 megagrams per year in the remaining areas of the Commonwealth, then the owner shall submit a periodic emission rate report as provided in 9VAC5-40-5880 D 1 and shall recalculate the NMOC mass emission rate annually, as provided in 9VAC5-40-5880 D 1 using the equations in subdivision B 1 of this section and using the site-specific methane generation rate constant and NMOC concentration obtained in subdivision B 3 of this section. 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.

5. The owner may use other methods to determine the NMOC concentration or a site-specific k as an alternative method required in subdivisions B 3 and B 4 of this section if the method has been approved by the board.

C. After the installation of a collection and control system in compliance with 9VAC5-40-5850, the owner shall calculate the NMOC emission rate for purposes of determining when the system can be removed as provided in 9VAC5-40-5820 C 2 e, using the following equation:

M_NMOC = 1.89 X 10^-3 Q_LFG C_NMOC

where

M_NMOC = mass emission rate of NMOC, megagrams per year

Q_LFG = flow rate of landfill gas, cubic meters per minute

C_NMOC = NMOC concentration, parts per million by volume as hexane

1. The flow rate of landfill gas, Q_LFG, 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 § 4 of Reference Method 2E of Appendix A of 40 CFR Part 60.

2. The average NMOC concentration, C_NMOC, 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 Reference Method 25C or Reference Method 18 of Appendix A of 40 CFR Part 60. If using Reference Method 18 of Appendix A of 40 CFR Part 60, the minimum list of compounds to be tested shall be those published in the "Compilation of Air Pollutant Emission Factors (AP-42)" (see 9VAC5-20-21). The sample location on the common header pipe shall be before any condensate removal or other gas refining units. The owner shall divide the NMOC concentration from Reference Method 25C of Appendix A of 40 CFR Part 60 by six to convert from C_NMOC as carbon to C_NMOC as hexane.

3. The owner may use an alternative method to determine landfill gas flow rate and NMOC concentration if the method has been approved by the board.

D. When calculating emissions for prevention of significant deterioration purposes, the owner of each MSW landfill subject to the provisions of this article shall estimate the NMOC emission rate for comparison to the prevention of significant deterioration major source and significance levels in Article 8 (9VAC5-80-1700 et seq.) of Part II of 9VAC5 Chapter 80 using the "Compilation of Air Pollutant Emission Factors (AP-42)" (see 9VAC5-20-21) or other measurement procedures acceptable to the board. If a collection system, which complies with the provisions in 9VAC5-40-5820 C 2 is already installed, the owner shall estimate the NMOC emission rate using the procedures provided in subsection C of this section.

E. For the compliance test required in 9VAC5-40-5820 C 2 c (2), Reference Method 25 or Reference Method 18 of Appendix A of 40 CFR Part 60 shall be used to determine compliance with 98 weight-percent efficiency or the 20 ppmv outlet concentration level, unless an alternative method to demonstrate compliance has been approved by the board as provided by 9VAC5-40-5820 C 2 a (2). If using Reference Method 18 of Appendix A of 40 CFR Part 60, the minimum list of compounds to be tested shall be those published in the "Compilation of Air Pollutant Emission Factors (AP-42)" (see 9VAC5-20-21). The following equation shall be used to calculate efficiency:

Control Efficiency = (NMOC_in - NMOC_out)/(NMOC_in)

where

NMOC_in = mass of NMOC entering control device

NMOC_out = mass of NMOC exiting control device