Page 1 of 31

Subpart TT—Industrial Waste Landfills

§ 98.460 Definition of the source category.

(a) This source category applies to industrial waste 

landfills that accepted waste on or after January 1, 1980, and 

that are located at a facility whose total landfill design 

capacity is greater than or equal to 300,000 metric tons.

(b) An industrial waste landfill is a landfill other than a 

municipal solid waste landfill, a RCRA Subtitle C hazardous 

waste landfill, or a TSCA hazardous waste landfill, in which 

industrial solid waste, such as RCRA Subtitle D wastes (nonhazardous industrial solid waste, defined in 40 CFR 257.2), 

commercial solid wastes, or conditionally exempt small quantity 

generator wastes, is placed. An industrial waste landfill 

includes all disposal areas at the facility.

(c) This source category does not include:

(1) Construction and demolition waste landfills.

(2) Industrial waste landfills that only receive one or 

more of the following inert waste materials:

(i) Coal combustion or incinerator ash (e.g., fly ash).

(ii) Cement kiln dust.

(iii) Rocks and/or soil from excavation and construction 

and similar activities.

(iv) Glass.

(v) Non-chemically bound sand (e.g., green foundry sand).
Page 2 of 31

(vii) Clay, gypsum, or pottery cull.

(viii) Bricks, mortar, or cement.

(ix) Furnace slag.

(x) Materials used as refractory (e.g., alumina, silicon, 

fire clay, fire brick).

(xi) Plastics (e.g., polyethylene, polypropylene, 

polyethylene terephthalate, polystyrene, polyvinyl chloride).

(xii) Other waste material that has a volatile solids 

concentration of 0.5 weight percent (on a dry basis) or less.

(xiii) Other waste material that has a DOC value of 0.3 

weight percent (on a wet basis) or less. DOC value must be 

determined using a 60-day anaerobic biodegradation test 

procedure identified in §98.464(b)(4)(i).

(d) This source category consists of the following sources 

at industrial waste landfills: Landfills, gas collection systems 

at landfills, and destruction devices for landfill gases 

(including flares).

§ 98.461 Reporting threshold.

You must report GHG emissions under this subpart if your 

facility contains an industrial waste landfill meeting the 

criteria in §98.460 and the facility meets the requirements of

§98.2(a)(2). For the purposes of §98.2(a)(2), the emissions from 

the industrial waste landfill are to be determined using the 

methane generation corrected for oxidation as determined using 
Page 3 of 31

Equation TT–6 of this subpart times the global warming potential 

for methane in Table A–1 of subpart A of this part.

§ 98.462 GHGs to report.

(a) You must report CH4 generation and CH4 emissions from 

industrial waste landfills.

(b) You must report CH4 destruction resulting from landfill 

gas collection and destruction devices, if present.

(c) You must report under subpart C of this part (General 

Stationary Fuel Combustion Sources) the emissions of CO2, CH4, 

and N2O from each stationary combustion unit associated with the 

landfill gas destruction device, if present, by following the 

requirements of subpart C of this part.

§ 98.463 Calculating GHG emissions.

(a) For each industrial waste landfill subject to the 

reporting requirements of this subpart, calculate annual modeled 

CH4 generation according to the applicable requirements in 

paragraphs (a)(1) through (a)(3) of this section. Apply Equation 

TT–1 of this section for each waste stream disposed of in the 

landfill and sum the CH4 generation rates for all waste streams 

disposed of in the landfill to calculate the total annual 

modeled CH4 generation rate for the landfill.

(1) Calculate annual modeled CH4 generation using Equation 

TT–1 of this section.
Page 4 of 31

  























        





    

1

( 1) ( )

4

12

16 T

x S

k T x k T x

CH x x F G W DOC MCF DOC F e e (Eq. TT-1)

Where:

GCH4 = Modeled methane generation in reporting year T 

(metric tons CH4).

X = Year in which waste was disposed.

S = Start year of calculation. Use the year 1960 or 

the opening year of the landfill, whichever is 

more recent.

T = Reporting year for which emissions are 

calculated.

WX = Quantity of waste disposed in the industrial 

waste landfill in year X from measurement data 

and/or other company records (metric tons, as 

received (wet weight)).

DOCX = Degradable organic carbon for waste disposed in 

year X from Table TT–1 to this subpart or from 

measurement data [as specified in paragraph 

(a)(3) of this section], if available [fraction 

(metric tons C/metric ton waste)].

DOCF = Fraction of DOC dissimilated (fraction); use the 

default value of 0.5. If measured values of DOC 

are available using the 60-day anaerobic 

biodegradation test procedure identified in 

§98.464(b)(4)(i), use a default value of 1.0.

MCF = Methane correction factor (fraction). Use the 

default value of 1 unless there is active 

aeration of waste within the landfill during the 

reporting year. If there is active aeration of 

waste within the landfill during the reporting 

year, use either the default value of 1 or select 

an alternative value no less than 0.5 based on 

site-specific aeration parameters.

F = Fraction by volume of CH4 in landfill gas 

(fraction, dry basis, corrected to 0% oxygen). If 

you have a gas collection system, use the annual 

average CH4 concentration from measurement data 

for the current reporting year; otherwise, use 

the default value of 0.5.
Page 5 of 31

k = Decay rate constant from Table TT–1 to this 

subpart (yr−1). Select the most applicable k 

value for the majority of the past 10 years (or 

operating life, whichever is shorter).

(2) Waste stream quantities. Determine annual waste 

quantities as specified in paragraphs (a)(2)(i) through (ii) of 

this section for each year starting with January 1, 1960 or the 

year the landfills first accepted waste if after January 1, 

1960, up until the most recent reporting year. The choice of 

method for determining waste quantities will vary according to 

the availability of historical data. Beginning in the first 

emissions reporting year (2011 or later) and for each year 

thereafter, use the procedures in paragraph (a)(2)(i) of this 

section to determine waste stream quantities. These procedures 

should also be used for any year prior to the first emissions 

reporting year for which the data are available. For other 

historical years, use paragraph (a)(2)(i) of this section, where 

waste disposal records are available, and use the procedures 

outlined in paragraph (a)(2)(ii) of this section when waste 

disposal records are unavailable, to determine waste stream 

quantities. Historical disposal quantities deposited ( i.e., 

prior to the first year in which monitoring begins) should only 

be determined once, as part of the first annual report, and the 

same values should be used for all subsequent annual reports, 

supplemented by the next year's data on new waste disposal.
Page 6 of 31

(i) Determine the quantity of waste (in metric tons as 

received, i.e., wet weight) disposed of in the landfill 

separately for each waste stream by any one or a combination of 

the following methods.

(A) Direct mass measurements.

(B) Direct volume measurements multiplied by waste stream 

density determined from periodic density measurement data or 

process knowledge.

(C) Mass balance procedures, determining the mass of waste 

as the difference between the mass of the process inputs and the 

mass of the process outputs.

(D) The number of loads (e.g., trucks) multiplied by the 

mass of waste per load based on the working capacity of the 

container or vehicle.

(ii) Determine the historical disposal quantities for 

landfills using the Waste Disposal Factor approach in paragraphs 

(a)(2)(ii)(A) and (B) of this section when historical production 

or processing data are available. If production or processing 

data are available for a given year, you must use Equation TT–3 

of this section for that year. Determine historical disposal 

quantities using the method specified in paragraph (a)(2)(ii)(C) 

of this section when historical production or processing data 

are not available, and for waste streams received from an offsite facility when historical disposal quantities cannot be 
Page 7 of 31

determined using the methods specified in paragraph (a)(2)(i) of 

this section.

(A) Determining Waste Disposal Factor: For each waste 

stream disposed of in the landfill, calculate the average waste 

disposal rate per unit of production or unit throughput using 

all available waste quantity data and corresponding production 

or processing rates for the process generating that waste or, if 

appropriate, the facility, using Equation TT–2 of this section.

Where:

WDF = Average waste disposal factor as determined for 

the first annual report required for this 

industrial waste landfill (metric tons per 

production unit).

X = Year in which waste was disposed. Include only 

those years for which disposal and production 

data are both available; the years do not need to 

be sequential.

Y1 = First year in which disposal and 

production/throughput data are both available.

Y2 = First year for which GHG emissions from this 

industrial waste landfill must be reported.

N = Number of years for which disposal and 

production/throughput data are both available.

Wx = Quantity of waste placed in the industrial waste 

landfill in year X from measurement data and/or 

other company records (metric tons, as received 

(wet weight)).

Px = Quantity of product produced or feedstock 

entering the process or facility in year X from 

measurement data and/or other company records 

(production units). You must use the same basis 
Page 8 of 31

for all years in the calculation. That is, Px must

be determined based on production (quantity of 

product produced) for all “N” years or Px must be 

determined based on throughput (quantity of 

feedstock) for all “N” years.

(B) Calculate waste: For each waste stream disposed of in 

the landfill, calculate the waste disposal quantities for 

historic years in which direct waste disposal measurements are 

not available using historical production data and Equation TT–3 

of this section.

Where:

X = Historic year in which waste was disposed.

Wx = Calculated quantity of waste placed in the 

landfill in year X (metric tons).

WDF = Average waste disposal factor from Equation TT–2 

of this section (metric tons per production 

unit).

Px = Quantity of product produced or feedstock 

entering the process or facility in year X from 

measurement data and/or other company records 

(production units). You must use the same basis 

for Px(either production only or throughput only) 

as used to determine WDF in Equation TT–2 of this 

section.

(C) For any year in which historic production or processing 

data are not available such that historic waste quantities 

cannot be estimated using Equation TT–3 of this section, 

calculate an average annual bulk waste disposal quantity using 

either Equation TT–4a of this section when data are available 

consecutively for the most recent disposal years or Equation TT–
Page 9 of 31

4b of this section when data are available for sporadic (nonconsecutive) years.

Where:

WX = Quantity of waste placed in the landfill in year 

X (metric tons, wet basis). This annual bulk 

waste disposal quantity applies for all years 

from “YrOpen” to “YrData” inclusive.

LFC = Capacity of the landfill used (or the total 

quantity of waste-in-place) at the end of the 

“YrData” from design drawings or engineering 

estimates (metric tons). For closed landfills for 

which waste quantity data are not available, use 

the landfill's design capacity.

YrData = The year prior to the year when waste disposal 

data are first available for all subsequent years 

from company records or from Equation TT–3 of 

this section. For landfills for which waste 

quantity data are not available, the year in 

which the landfill last received waste.

YrOpen = Year 1960 or the year in which the landfill first 

received waste from company records, whichever is 

more recent. If no data are available for 

estimating YrOpen for a closed landfill, use 1960 

as the default “YrOpen” for the landfill.

YrLast YrOpen NYrData

WIP W

W

NYrData

n

meas n

x

  







1

1

,

(Eq. TT-4b)

Where:

WX = Quantity of waste placed in the landfill in year 

X (metric tons, wet basis). This annual bulk 

waste disposal quantity applies for all years for 

which waste quantity data are not available from 

company records or from Equation TT–3 of this 

section.
Page 10 of 31

WIP = Quantity of waste in-place at the start of the 

reporting year from design drawings or 

engineering estimates (metric tons). For closed 

landfills for which waste in-place quantities are 

not available, use the landfill's design 

capacity.

Wmeas,n = Annual quantity of waste placed in the landfill 

for the nth measurement year from company records 

or from Equation TT–3 of this section.

YrLast = The last year, prior to the reporting year, that 

the landfill received waste.

YrOpen = Year 1960 or the year in which the landfill first 

received waste from company records, whichever is 

more recent. If no data are available for 

estimating YrOpen for a closed landfill, use 1960 

as the default “YrOpen” for the landfill.

NYrData = The number of years for which annual waste 

disposal quantities are available from company 

records or from Equation TT–3 of this section 

from YrOpen to YrLast inclusive.

(3) Degradable organic content (DOC). For any year, X, in 

Equation TT–1 of this section, use either the applicable default 

DOC values provided in Table TT–1 of this subpart or determine 

values for DOCx as specified in paragraphs (a)(3)(i) through (iv) 

of this section. When developing historical waste quantity data, 

you may use default DOC values from Table TT–1 of this subpart 

for certain years and determined values for DOCx for other 

years. The historical values for DOC or DOCx must be developed 

only for the first annual report required for the industrial 

waste landfill; and used for all subsequent annual reports ( 

e.g., if DOC for year x=1990 was determined to be 0.15 in the 
Page 11 of 31

first reporting year, you must use 0.15 for the 1990 DOC value 

for all subsequent annual reports).

(i) For the first year in which GHG emissions from this 

industrial waste landfill must be reported, determine the DOCx

value of each waste stream disposed of in the landfill no less 

frequently than once per quarter using the methods specified in 

§98.464(b). Calculate annual DOCx for each waste stream as the 

arithmetic average of all DOCx values for that waste stream that 

were measured during the year.

(ii) For subsequent years (after the first year in which 

GHG emissions from this industrial waste landfill must be 

reported), either use the DOCx of each waste stream calculated 

for the most recent reporting year for which DOC values were 

determined according to paragraph (a)(3)(i) of this section, or 

determine new DOC values for that year following the 

requirements in paragraph (a)(3)(i) of this section. You must 

determine new DOC values following the requirements in paragraph 

(a)(3)(i) of this section if changes in the process operations 

occurred during the previous reporting year that can reasonably 

be expected to alter the characteristics of the waste stream, 

such as the water content or volatile solids concentration. 

Should changes to the waste stream occur, you must revise the 

GHG Monitoring Plan as required in §98.3(g)(5)(iii) and report 

the new DOCx value according to the requirements of §98.466.
Page 12 of 31

(iii) If DOCx measurement data for each waste stream are 

available according to the methods specified in §98.464(b) for 

years prior to the first year in which GHG emissions from this 

industrial waste landfill must be reported, determine DOCx for

each waste stream as the arithmetic average of all DOCx values

for that waste stream that were measured in Year X. A single 

measurement value is acceptable for determining DOCx for years 

prior to the first reporting year.

(iv) For historical years for which DOCx measurement data, 

determined according to the methods specified in §98.464(b), are 

not available, determine the historical values for DOCx using the 

applicable methods specified in paragraphs (a)(3)(iv)(A) and (B) 

of this section. Determine these historical values for DOCx only

for the first annual report required for this industrial waste 

landfill; historical values for DOCx calculated for this first 

annual report should be used for all subsequent annual reports.

(A) For years in which waste stream-specific disposal 

quantities are determined (as required in paragraphs (a)(2) 

(ii)(A) and (B) of this section), calculate the average DOC 

value for a given waste stream as the arithmetic average of all 

DOC measurements of that waste stream that follow the methods 

provided in §98.464(b), including any measurement values for 

years prior to the first reporting year and the four measurement 

values required in the first reporting year. Use the resulting 
Page 13 of 31

waste-specific average DOC value for all applicable years (i.e., 

years in which waste stream-specific disposal quantities are 

determined) for which direct DOC measurement data are not 

available.

(B) For years for which bulk waste disposal quantities are 

determined according to paragraphs (a)(2)(ii)(C) of this 

section, calculate the weighted average bulk DOC value according 

to the following: Calculate the average DOC value for each waste 

stream as the arithmetic average of all DOC measurements of that 

waste stream that follows the methods provided in §98.464(b) 

(generally, this will include only the DOC values determined in 

the first year in which GHG emissions from this industrial waste 

landfill must be reported); calculate the average annual 

disposal quantity for each waste stream as the arithmetic 

average of the annual disposal quantities for each year in which 

waste stream-specific disposal quantities have been determined; 

and calculate the bulk waste DOC value using Equation TT–5 of 

this section. Use the bulk waste DOC value as DOCx for all years 

for which bulk waste disposal quantities are determined 

according to paragraphs (a)(2)(ii)(C) of this section.

Where:
Page 14 of 31

DOCbulk = Degradable organic content value for bulk 

historical waste placed in the landfill (mass 

fraction).

N = Number of different waste streams placed in the 

landfill.

n = Index for waste stream.

DOCave,n = Average degradable organic content value for 

waste stream “n” based on available measurement 

data (mass fraction).

Wave,n = Average annual quantity of waste stream “n” 

placed in the landfill for years in which waste 

stream-specific disposal quantities have been 

determined (metric tons per year, wet basis).

(b) For each landfill, calculate CH4 generation (adjusted 

for oxidation in cover materials) and CH4 emissions (taking into 

account any CH4 recovery, if applicable, and oxidation in cover 

materials) according to the applicable methods in paragraphs 

(b)(1) through (b)(3) of this section.

(1) For each landfill, calculate CH4 generation, adjusted 

for oxidation, from the modeled CH4 (GCH4 from Equation TT–1 of 

this section) using Equation TT–6 of this section.

Where:

MG = Methane generation, adjusted for oxidation, from 

the landfill in the reporting year (metric tons 

CH4).

GCH4 = Modeled methane generation rate in reporting year 

from Equation TT–1 of this section (metric tons 

CH4).

OX = Oxidation fraction from Table HH-4 of subpart HH 

of this part.
Page 15 of 31

(2) For landfills that do not have landfill gas collection 

systems operating during the reporting year, the CH4 emissions 

are equal to the CH4 generation (MG) calculated in Equation TT–6 

of this section.

(3) For landfills with landfill gas collection systems in 

operation during any portion of the reporting year, perform all 

of the calculations specified in paragraphs (b)(3)(i) through 

(iv) of this section.

(i) Calculate the quantity of CH4 recovered according to the 

requirements at §98.343(b).

(ii) Calculate CH4 emissions using the Equation HH–6 of 

§98.343(c)(3)(i), except use GCH4 determined using Equation TT–1 

of this section in Equation HH–6 of §98.343(c)(3)(i).

(iii) Calculate CH4 generation (MG) from the quantity of CH4

recovered using Equation HH–7 of §98.343(c)(3)(ii).

(iv) Calculate CH4 emissions from the quantity of CH4

recovered using Equation HH–8 of §98.343(c)(3)(ii).

§ 98.464 Monitoring and QA/QC requirements.

(a) For calendar year 2011 monitoring, the facility may 

submit a request to the Administrator to use one or more best 

available monitoring methods as listed in §98.3(d)(1)(i) through 

(iv). The request must be submitted no later than October 12, 

2010 and must contain the information in §98.3(d)(2)(ii). To 

obtain approval, the request must demonstrate to the 
Page 16 of 31

Administrator's satisfaction that it is not reasonably feasible 

to acquire, install, and operate a required piece of monitoring 

equipment by January 1, 2011. The use of best available 

monitoring methods will not be approved beyond December 31, 

2011.

(b) For each waste stream placed in the landfill during the 

reporting year for which you choose to determine volatile solids 

concentration and/or a waste stream-specific DOCX, you must 

collect and test a representative sample of that waste stream 

using the methods specified in paragraphs (b)(1) through (b)(4) 

of this section, as applicable.

(1) Develop and follow a sampling plan to collect a 

representative sample (in terms of composition and moisture 

content) of each waste stream placed in the landfill for which 

testing is elected.

(2) Determine the percent total solids and the percent 

volatile solids of each sample following Standard Method 2540G 

“Total, Fixed, and Volatile Solids in Solid and Semisolid 

Samples” (incorporated by reference; see §98.7).

(3) For the purposes of §98.460(c)(2)(xii), the volatile 

solids concentration (weight percent on a dry basis) is the 

percent volatile solids determined using Standard Method 2540G 

“Total, Fixed, and Volatile Solids in Solid and Semisolid 

Samples” (incorporated by reference; see §98.7).
Page 17 of 31

(4) Determine DOC value of a waste stream by either using 

at least a 60-day anaerobic biodegradation test as specified in 

paragraph (b)(4)(i) of this section or by estimating the DOC 

value based on the total and volatile solids measurements as 

specified in paragraph (b)(4)(ii) of this section.

(i) Perform an anaerobic biodegradation test and determine 

the DOC value of a waste stream following the procedures and 

requirements in paragraphs (b)(4)(i)(A) through (E) of this 

section.

(A) You may use the procedures published by a consensusbased standards organization to conduct a minimum of a 60-day 

anaerobic biodegradation test. Consensus-based standards 

organizations include, but are not limited to, the following: 

ASTM International (100 Barr Harbor Drive, P.O. Box CB700, West 

Conshohocken, Pennsylvania 19428–B2959, (800) 262–1373, 

http://www.astm.org), the American National Standards Institute 

(ANSI, 1819 L Street, NW., 6th floor, Washington, DC 20036, 

(202) 293–8020, http://www.ansi.org), the American Society of 

Mechanical Engineers (ASME, Three Park Avenue, New York, NY 

10016–5990, (800) 843–2763, http://www.asme.org), and the North 

American Energy Standards Board (NAESB, 801 Travis Street, Suite 

1675, Houston, TX 77002, (713) 356–0060, http://www.api.org).

(B) Use a minimum of four samples: Two waste stream 

samples, a control sample using a known substrate (such as 
Page 18 of 31

ethanol), and a digester sludge blank sample. Each waste stream 

sample must be appropriately ground to ensure the waste material 

is fully exposed to the anaerobic digester sludge.

(C) Determine the net mass of carbon degraded in the 

control sample as the difference in the results of the control 

sample and the digester sludge blank sample. Determine the net 

mass of carbon degraded in each waste stream sample as the 

difference in the results of each waste stream sample and the 

digester sludge blank sample.

(D) Determine the fraction of carbon degraded in the 

control sample as the net mass of carbon degraded in the control 

sample divided by the mass of carbon added via the substrate 

material in the control sample. If less than 50 percent of the 

theoretical mass of carbon in the control sample is degraded, 

the test run is invalid.

(E) Determine the DOC of each waste sample using Equation 

TT–7 of this section. If the DOC values for the two waste stream 

samples differ by more than 20 percent, the test run is invalid.

The DOC of the waste stream is determined as the average DOC 

value of the two waste stream samples determined during a valid 

test.

sample,x

sample,x

x M

MCD

DOC  (Eq. TT-7)

Where:
Page 19 of 31

DOCX = Degradable organic content of the waste stream in 

Year X (weight fraction, wet basis)

MCDsample,x = Mass of carbon degraded in the waste stream sample 

in Year X as determined in paragraph (b)(4)(i)(C) 

of this section [milligrams (mg)].

Msample,x = Mass of waste stream sample used in the anaerobic 

degradation test in Year X (mg, wet basis).

(ii) Calculate the waste stream-specific DOCx value using 

Equation TT–8 of this section.

Where:

DOCX = Degradable organic content of waste stream 

in Year X (weight fraction, wet basis)

FDOC = Fraction of the volatile residue that is 

degradable organic carbon (weight 

fraction). Use a default value of 0.6.

% Volatile SolidsX = Percent volatile solids determined using 

Standard Method 2540G Total, “Fixed, and 

Volatile Solids in Solid and Semisolid 

Samples” (incorporated by reference; see 

§98.7) for Year X [milligrams (mg) 

volatile solids per 100 mg dried solids].

% Total SolidsX = Percent total solids determined using 

Standard Method 2540G “Total, Fixed, and 

Volatile Solids in Solid and Semisolid 

Samples” (incorporated by reference; see 

§98.7) for Year X (mg dried solids per 100 

mg wet waste).

(c) For each waste stream that was historically managed in 

the landfill for which you choose to determine volatile solids 

concentration and/or a waste stream-specific DOCX, you must 

determine volatile solids concentration or DOCX of the waste 
Page 20 of 31

stream as initially placed in the landfill using the methods 

specified in paragraph (c)(1) or (c)(2) of this section, as 

applicable.

(1) If you can identify a similar waste stream to the waste 

stream that was historically managed in the landfill, you must 

determine the volatile solids concentration or DOCX of the 

similar waste stream using the applicable procedures in 

paragraphs (b)(1) through (b)(4) of this section.

(2) If you cannot identify a similar waste stream to the 

waste stream that was historically managed in the landfill, you 

may determine the volatile solids concentration or DOCX of the 

historically managed waste stream using process knowledge. You 

must document the basis for the volatile solids concentration or 

DOCX value as determined through process knowledge.

(d) For landfills with gas collection systems, operate, 

maintain, and calibrate a gas composition monitor capable of 

measuring the concentration of CH4 according to the requirements 

specified at §98.344(b).

(e) For landfills with gas collection systems, install, 

operate, maintain, and calibrate a gas flow meter capable of 

measuring the volumetric flow rate of the recovered landfill gas 

according to the requirements specified at §98.344(c).

(f) For landfills with gas collection systems, all 

temperature, pressure, and if applicable, moisture content 
Page 21 of 31

monitors must be calibrated using the procedures and frequencies 

specified by the manufacturer.

(g) For landfills electing to measure the fraction by 

volume of CH4 in landfill gas (F), follow the requirements in 

paragraphs (g)(1) and (g)(2) of this section.

(1) Use a gas composition monitor capable of measuring the 

concentration of CH4 on a dry basis that is properly operated, 

calibrated, and maintained according to the requirements 

specified at §98.344(b). You must either use a gas composition 

monitor that is also capable of measuring the O2 concentration 

correcting for excess (infiltration) air or you must operate, 

maintain, and calibrate a second monitor capable of measuring 

the O2 concentration on a dry basis according to the 

manufacturer's specifications.

(2) Use Equation TT–9 of this section to correct the 

measured CH4 concentration to 0% oxygen. If multiple CH4

concentration measurements are made during the reporting year, 

determine F separately for each measurement made during the 

reporting year, and use the results to determine the arithmetic 

average value of F for use in Equation TT–1 of this part.

Where:

F = Fraction by volume of CH4 in landfill gas 

(fraction, dry basis, corrected to 0% oxygen).
Page 22 of 31

CCH4 = Measured CH4 concentration in landfill gas 

(volume %, dry basis).

20.9c = Defined O2correction basis, (volume %, dry 

basis).

20.9 = O2concentration in air (volume %, dry basis).

%O2 = Measured O2concentration in landfill gas 

(volume %, dry basis).

(h) The facility shall document the procedures used to 

ensure the accuracy of the estimates of disposal quantities and, 

if the industrial waste landfill has a gas collection system, 

gas flow rate, gas composition, temperature, pressure, and 

moisture content measurements. These procedures include, but are 

not limited to, calibration of weighing equipment, fuel flow 

meters, and other measurement devices. The estimated accuracy of 

measurements made with these devices shall also be recorded, and 

the technical basis for these estimates shall be provided.

§ 98.465 Procedures for estimating missing data.

(a) A complete record of all measured parameters used in 

the GHG emissions calculations is required. Therefore, whenever 

a quality-assured value of a required parameter is unavailable 

(e.g., if a meter malfunctions during unit operation or if a 

required fuel sample is not taken), a substitute data value for 

the missing parameter shall be used in the calculations, in 

accordance with paragraph (b) of this section.
Page 23 of 31

(b) For industrial waste landfills with gas collection 

systems, follow the procedures for estimating missing data 

specified in §98.345(a) and (b).

§ 98.466 Data reporting requirements.

In addition to the information required by §98.3(c), each 

annual report must contain the following information for each 

landfill.

(a) Report the following general landfill information:

(1) A classification of the landfill as “open” (actively 

received waste in the reporting year) or “closed” (no longer 

receiving waste).

(2) The year in which the landfill first started accepting 

waste for disposal.

(3) The last year the landfill accepted waste (for open 

landfills, enter the estimated year of landfill closure).

(4) The capacity (in metric tons) of the landfill.

(5) An indication of whether leachate recirculation is used 

during the reporting year and its typical frequency of use over 

the past 10 years (e.g., used several times a year for the past 

10 years, used at least once a year for the past 10 years, used 

occasionally but not every year over the past 10 years, not 

used).

(b) Report the following waste characterization and 

modeling information:
Page 24 of 31

(1) The number of waste steams (including “Other Industrial 

Solid Waste (not otherwise listed)” and “Inerts”) for which 

Equation TT–1 of this subpart is used to calculate modeled CH4

generation.

(2) A description of each waste stream (including the types 

of materials in each waste stream) for which Equation TT–1 of 

this subpart is used to calculate modeled CH4 generation.

(3) The fraction of CH4 in the landfill gas, F, (volume 

fraction, dry basis, corrected to 0% oxygen) for the reporting 

year and an indication as to whether this was the default value 

or a value determined through measurement data.

(4) The methane correction factor (MCF) value used in the 

calculations. If an MCF value other than the default of 1 is 

used, provide a description of the aeration system, including 

aeration blower capacity, the fraction of the landfill 

containing waste affected by the aeration, the total number of 

hours during the year the aeration blower was operated, and 

other factors used as a basis for the selected MCF value.

(5) For each waste stream, the decay rate (k) value used in 

the calculations.

(c) Report the following historical waste information:

(1) [Reserved]

(2) For each waste stream identified in paragraph (b) of 

this section, the method(s) for estimating historical waste 
Page 25 of 31

disposal quantities and the range of years for which each method 

applies.

(3) For each waste stream identified in paragraph (b) of 

this section for which Equation TT–2 of this subpart is used, 

provide:

(i) The total number of years (N) for which disposal and 

production data are both available.

(ii) The year, the waste disposal quantity and production 

quantity for each year used in Equation TT–2 of this subpart to 

calculate the average waste disposal factor (WDF).

(iii) The average waste disposal factor (WDF) calculated 

for the waste stream.

(4) If Equation TT–4a of this subpart is used, provide:

(i) The value of landfill capacity (LFC).

(ii) YrData.

(iii) YrOpen.

(5) If Equation TT-4b of this subpart is used, provide: 

(i) WIP (i.e., the quantity of waste in-place at the start 

of the reporting year from design drawings or engineering 

estimates (metric tons) or, for closed landfills for which waste 

in-place quantities are not available, the landfill's design 

capacity).

(ii) The cumulative quantity of waste placed in the 

landfill for the years for which disposal quantities are 
Page 26 of 31

available from company record or from Equation TT-3 of this 

part.

(iii) YrLast.

(iv) YrOpen.

(v) NYrData.

(d) For each year of landfilling starting with the “Start 

Year” (S) and each year thereafter up to the current reporting 

year, report the following information:

(1) The calendar year for which the following data elements 

apply.

(2) The quantity of waste (WX) disposed of in the landfill 

(metric tons, wet weight) for the specified year for each waste 

stream identified in paragraph (b) of this section.

(3) For each waste stream, the degradable organic carbon 

(DOCX) value (mass fraction) for the specified year and an 

indication as to whether this was the default value from Table 

TT–1 to this subpart, a measured value using a 60-day anaerobic 

biodegradation test as specified in §98.464(b)(4)(i), or a value 

based on total and volatile solids measurements as specified in 

§98.464(b)(4)(ii). If DOCx was determined by a 60-day anaerobic 

biodegradation test, specify the test method used.

(e) Report the following information describing the 

landfill cover material:
Page 27 of 31

(1) The type of cover material used (as either organic 

cover, clay cover, sand cover, or other soil mixtures).

(2) For each type of cover material used, the surface area 

(in square meters) at the start of the reporting year for the 

landfill sections that contain waste and that are associated 

with the selected cover type.

(f) The modeled annual methane generation (GCH4) for the 

reporting year (metric tons CH4) calculated using Equation TT–1 

of this subpart.

(g) For landfills without gas collection systems, provide:

(1) The annual methane emissions (i.e., the methane 

generation (MG), adjusted for oxidation, calculated using 

Equation TT–6 of this subpart), reported in metric tons CH4.

(2) An indication of whether passive vents and/or passive 

flares (vents or flares that are not considered part of the gas 

collection system as defined in §98.6) are present at this 

landfill.

(h) For landfills with gas collection systems, in addition 

to the reporting requirements in paragraphs (a) through (f) of 

this section, provide: 

(1) The annual methane generation, adjusted for oxidation, 

calculated using Equation TT-6 of this subpart, reported in 

metric tons CH4.
Page 28 of 31

(2) The oxidation factor used in Equation TT-6 of this 

subpart.

(3) All information required under 40 CFR 98.346(i)(1) 

through (i)(7) and 40 CFR 98.346(i)(9) through (i)(12). 

§ 98.467 Records that must be retained.

In addition to the information required by §98.3(g), you 

must retain the calibration records for all monitoring 

equipment, including the method or manufacturer's specification 

used for calibration, and all measurement data used for the 

purposes of paragraphs §98.460(c)(2)(xii) or (c)(2)(xiii) or

used to determine waste stream-specific DOCX values for use in 

Equation TT-1 of this subpart.

§ 98.468 Definitions.

Except as provided below, all terms used in this subpart 

have the same meaning given in the CAA and subpart A of this 

part.

Construction and demolition (C&D) waste landfill means a 

solid waste disposal facility subject to the requirements of 

subparts A or B of part 257 of this chapter that receives 

construction and demolition waste and does not receive hazardous 

waste (defined in §261.3 of this chapter) or industrial solid 

waste (defined in §258.2 of this chapter) or municipal solid 

waste (defined in §98.6 of this part) other than residential 

lead-based paint waste. A C&D waste landfill typically receives 
Page 29 of 31

any one or more of the following types of solid wastes: roadwork 

material, excavated material, demolition waste, 

construction/renovation waste, and site clearance waste.

Design capacity means the maximum amount of solid waste a 

landfill can accept. For the purposes of this subpart, for 

landfills that have a permit, the design capacity can be 

determined in terms of volume or mass in the most recent permit 

issued by the state, local, or Tribal agency responsible for 

regulating the landfill, plus any in-place waste not accounted 

for in the most recent permit. If the owner or operator chooses 

to convert the design capacity from volume to mass to determine 

its design capacity, the calculation must include a sitespecific density. If the design capacity is within 10 percent of 

the applicability threshold in §98.460(a) and there is a change 

in the production process that can reasonably be expected to 

change the site-specific waste density, the site-specific waste 

density must be redetermined and the design capacity must be 

recalculated based on the new waste density.

Industrial sludge means the residual, semi-solid material 

left from industrial wastewater treatment processes or wet air 

pollution control devices (e.g., wet scrubbers). Industrial 

sludge includes underflow material collected in primary or 

secondary clarifiers, settling basins, or precipitation tanks as 

well as dredged materials from wastewater tanks or impoundments. 
Page 30 of 31

Industrial sludge also includes the semi-solid materials 

remaining after these materials are dewatered via a belt 

process, centrifuge, or similar dewatering process.

Solid waste has the meaning established by the 

Administrator pursuant to the Solid Waste Disposal Act (42 

U.S.C.A. 6901 et seq.).

Waste stream means industrial solid waste material that is 

generated by a specific manufacturing process or client. For 

wastes generated at the facility that includes the industrial 

waste landfill, a waste stream is the industrial solid waste 

material generated by a specific processing unit at that 

facility. For industrial solid wastes that are received from 

off-site facilities, a waste stream can be defined as each waste 

shipment or group of waste shipments received from a single 

client or group of clients that produce industrial solid wastes 

with similar waste properties.

Table TT–1 to Subpart TT—Default DOC and Decay Rate Values for 

Industrial Waste Landfills

Industry/Waste Type

DOC

(weight 

fraction, 

wet basis)

k

[dry 

climatea]

(yr−1)

k

[moderate 

climatea]

(yr−1)

k

[wet 

climatea]

(yr−1)

Food Processing

(other than 

industrial sludge)

0.22 0.06 0.12 0.18

Pulp and Paper (other 

than industrial 

sludge)

0.20 0.02 0.03 0.04
Page 31 of 31

Wood and Wood Product

(other than 

industrial sludge)

0.43 0.02 0.03 0.04

Construction and 

Demolition

0.08 0.02 0.03 0.04

Industrial Sludge 0.09 0.02 0.04 0.06

Inert Waste [i.e.,

wastes listed in 

§98.460(c)(2)]

0 0 0 0

Other Industrial 

Solid Waste (not 

otherwise listed)

0.20 0.02 0.04 0.06

aThe applicable climate classification is determined based on the annual 

rainfall plus the recirculated leachate application rate. Recirculated 

leachate application rate (in inches/year) is the total volume of leachate 

recirculated from company records or engineering estimates and applied to the 

landfill divided by the area of the portion of the landfill containing waste 

[with appropriate unit conversions].

(1) Dry climate = precipitation plus recirculated leachate less than 20 

inches/year

(2) Moderate climate = precipitation plus recirculated leachate from 20 

to 40 inches/year (inclusive)

(3) Wet climate = precipitation plus recirculated leachate greater than 

40 inches/year

Alternatively, landfills that use leachate recirculation can elect to 

use the k value for wet climate rather than calculating the recirculated 

leachate rate.