Page 1 of 26

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 (non-hazardous 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).

(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).
Page 2 of 26

(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 

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 
Page 3 of 26

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.

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)].
Page 4 of 26

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.

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 
Page 5 of 26

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.

(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 off-site facility when 

historical disposal quantities cannot be 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 
Page 6 of 26

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 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. 
Page 7 of 26

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-4b of this 

section when data are available for sporadic (non-consecutive) 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.
Page 8 of 26

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.

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.

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.
Page 9 of 26

(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 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 
Page 10 of 26

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. 

(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 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. 
Page 11 of 26

(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: 

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).
Page 12 of 26

(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.

(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). 
Page 13 of 26

(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 

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 
Page 14 of 26

“Total, Fixed, and Volatile Solids in Solid and Semisolid Samples” (incorporated by reference; 

see §98.7).

(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 consensus-based 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 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.
Page 15 of 26

(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.

Where:

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:
Page 16 of 26

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 stream as initially placed in the 

landfill using the methods specified in paragraph (c)(1) or (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 (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.
Page 17 of 26

(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 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:
Page 18 of 26

F = Fraction by volume of CH4 in landfill gas (fraction, dry basis, corrected to 0% 

oxygen).

CCH4 = Measured CH4 concentration in landfill gas (volume %, dry basis).

20.9c = Defined O2 correction basis, (volume %, dry basis).

20.9 = O2 concentration in air (volume %, dry basis).

%O2 = Measured O2 concentration 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.

(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.
Page 19 of 26

(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:

(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 
Page 20 of 26

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 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) Reserved.

(ii) The year of the data used in Equation TT-2 for the waste disposal quantity and 

production quantity, for each year used in Equation TT-2 of § 98.463 to calculate the average 

waste disposal factor (WDF).

(iii) Reserved.

(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).
Page 21 of 26

(ii) The cumulative quantity of waste placed in the landfill for the years for which 

disposal quantities are 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:

(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.
Page 22 of 26

(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 TT6 of this subpart, reported in metric tons CH4.

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

(3) All information required under 40 CFR 98.346(i)(1) through (7) and 40 CFR 

98.346(i)(9) through (12).

§ 98.467 Records that must be retained.

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

(a) 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 (xiii) or used to determine waste stream-specific DOCX 

values for use in Equation TT-1 of § 98.463.

(b) Verification software records. You must keep a record of the file generated by the 

verification software specified in § 98.5(b) for the applicable data specified in paragraphs (b)(1) 
Page 23 of 26

through (3) of this section. Retention of this file satisfies the recordkeeping requirement for the 

data in paragraphs (b)(1) and (2) of this section.

(1) Quantity of each product produced or feedstock entering the process or facility per 

waste stream per year, from measurement data and/or other company records. You must use the 

same basis for all years in the calculation (i.e., based on production or based on quantity of 

feedstock) (metric tons) (Equation TT-2 of § 98.463).

(2) [Reserved].

§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 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 
Page 24 of 26

mass to determine its design capacity, the calculation must include a site-specific 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. 

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 of Part 98—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)
Page 25 of 26

Food Processing (other than 

industrial sludge)

0.22 0.0

6

0.12 0.1

8

Pulp and Paper Industry:

Boiler Ash 0.06 0.0

2

0.03 0.0

4

Wastewater Sludge 0.12 0.0

2

0.04 0.0

6

Kraft Recovery Wastesb0.025 0.0

2

0.03 0.0

4

Other Pulp and Paper Wastes 

(not otherwise listed)

0.20 0.0

2

0.03 0.0

4

Wood and Wood Product (other 

than industrial sludge)

0.43 0.0

2

0.03 0.0

4

Construction and Demolition 0.08 0.0

2

0.03 0.0

4

Industrial Sludge (other than pulp 

and paper industry sludge)

0.09 0.0

2

0.04 0.0

6

Inert Waste [i.e., wastes listed in 

§98.460(c)(2)]

0 0 0 0

Other Industrial Solid Waste (not 

otherwise listed)

0.20 0.0

2

0.04 0.0

6

a

The 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
Page 26 of 26

Alternatively, landfills that use leachate recirculation can elect to use the k value for wet 

climate rather than calculating the recirculated leachate rate.

bKraft Recovery Wastes include green liquor dregs, slaker grits, and lime mud, which 

may also be referred to collectively as causticizing or recausticizing wastes.