This page provides a step-by-step description of how to enter and edit information on the methane generated and emitted from industrial waste landfills as required by Subpart TT of the Greenhouse Gas Reporting Program (GHGRP).

Subpart TT requires industrial waste landfills to report methane (CH

_{4}) generation and emissions quantities. First, provide the information requested in the Landfill Details page and e-GGRT will determine what additional information is required for reporting based on the information that you provide about your landfill (e.g., whether or not your landfill has Gas Collection System). Next, identify each waste stream placed into the landfill and provide the associated information requested by e-GGRT.

##### If there is no Gas Collection System at your Landfill

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From the Subpart Overview page, click the OPEN button located opposite “Methane Generation and Emissions for Landfills without LFG Collection Systems.”

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This page displays a summary of the CH_{4} data calculated by e-GGRT. Click NEXT to move on to the next page.

For each equation:

- Hover over an element in the equation to read a definition of that element as needed.
- On these equation pages, you will have the option to use the result calculated by e-GGRT or enter your own result by clicking on one of the following radio buttons at the bottom of the page:
- "Use the calculated result rounded"
- "Enter my own result (value will be rounded)"

__Methane Oxidation Fraction__

Please note that the Methane Oxidation Fraction may only be provided for RY2013 and later. Prior to RY2013, the default of 0.10 was used in all cases and the following methane oxidation fraction page is not available.

Please provide the Methane Oxidation Fraction for your landfill using the screen below. For assistance in determining the methane oxidation fraction, please consult the Methane Flux Calculation Spreadsheet.

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Click NEXT to move on to the "Equation TT-1 Summary and Result" page.

Equation TT-1 Summary and Result

On this page, e-GGRT will calculate the modeled annual methane generation (G_{CH4}) in metric tons per year (the output of Equation TT-1) for each waste stream identified. e-GGRT will calculate your total annual modeled CH_{4} generation with Equation TT-Q by summing each waste stream-specific Equation TT-1 result, rounding the value according to e-GGRT rounding rules, and storing both the rounded and unrounded values in the database.

e-GGRT will also allow you to report the modeled annual methane generation (G_{CH4}) in metric tons per year (the output of Equation TT-1). To enter a value, click the "Enter my own result" button and enter your result in the box that shows up below the question. e-GGRT will store your estimated value of modeled annual methane generation (G_{CH4}) in metric tons per year (the output of Equation TT-1), round the value to the nearest metric ton, and store the rounded value and the facility-entered unrounded value in the database.

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Click NEXT to move on to the "Equation TT-6 Summary and Result" page.

Equation TT-6 Summary and Result

On this page, e-GGRT will calculate the landfill's annual methane generation adjusted for oxidation using Equation TT-6. e-GGRT will then round the result according to e-GGRT rounding rules and store both the rounded and unrounded values in the database.

You may use this result or enter your own value by clicking the "Enter my own result" button. Enter your result in the box that shows up below the question. e-GGRT will store your estimated value, round the value to the nearest metric ton (integer), and store both the rounded and unrounded value in the database.

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When you have entered the information, click FINISHED. This will save the information reported on this page and take you to the summary page. Then click Subpart Overview to return to the Subpart Overview page.

Note: If you click NEXT at the bottom of Methane Generation and Emissions page, you will be taken back through all of the pages related to the equations listed in the gray box. Click SUBPART OVERVIEW to exit this loop.

##### If there is a Gas Collection System at your Landfill

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__Estimated Waste Depths Overview__

From the Subpart Overview page, press the OPEN button located opposite “Estimated Waste Depths.”

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For landfills with a gas collection system in place, the following information must be entered on the estimate waste depths (in meters) and surface areas (in square meters) for each area below (as listed in Table HH-3). If an area type, A1 through A5, is not found at the facility, enter zero for the surface area and waste depth for that area type. For each area type, A1 through A5, for which the surface area or waste depth is zero, enter a zero in that data field:

**A1:**Depth and surface area of area with no waste in place. Note: In many cases, the depth of area with no waste in place will be zero.**A2:**Depth and surface area of area without active gas collection, regardless of cover type.**A3:**Depth and surface area of area with daily soil cover and active gas collection.**A4:**Depth and surface area of area with an intermediate soil cover, or a final soil cover not meeting the criteria for A5 and active gas collection.**A5:**Depth and surface area of area with a final soil cover of 3 feet or thicker of clay and/or geomembrane cover system and active gas collection.

When you have entered the information, click SAVE. You will be brought back to the top of the page at which time you may check over the information you entered. When you have completed your check, click Subpart Overview to return to the Subpart Overview page.

__Emissions Reporting Overview for Landfills with Gas Collection System__

From the Subpart TT Overview page, click the OPEN button located opposite “Methane Generation and Emissions for Landfills with LFG Collection Systems.”

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On the first page, the following information is collected:

- Total volumetric flow of landfill gas collected for destruction (in scf)
- Indicate if a missing data procedure was used to determine the volume of the landfill gas collected for destruction (information about appropriate procedures for estimating missing data is found in §98.345.
- If a missing data procedure was used, enter the number of days when substitute data were used to determine the volume of the landfill gas collected for destruction

- Annual average concentration of CH
_{4}of landfill gas collected for destruction - Indicate if a missing data procedure was used to determine the concentration of CH
_{4}in landfill gas collected for destruction (information about appropriate procedures for estimating missing data are found in §98.345).- If a missing data procedure was used and the CH
_{4}concentration is monitored continuously, enter the number of days substitute data were used to determine the annual average CH_{4}concentration of landfill gas collected for destruction - If a missing data procedure was used and the CH
_{4}concentration is monitored monthly, enter the number of months substitute data were used to determine the annual average CH_{4}concentration of landfill gas collected for destruction - In the case of multiple measurement locations, you may enter values for both days and months when CH
_{4}concentration is measured continuously at some locations and monthly at others.

- If a missing data procedure was used and the CH
- Indicate (yes/no) if temperature was incorporated into internal calculations run by the collection system’s monitoring equipment
- If temperature was not incorporated into the internal calculations run by the collection system’s monitoring equipment, enter the average monthly temperature at which the landfill gas flow was measured (in degrees Rankine) for each month of the reporting year.

- Indicate (yes/no) if pressure was incorporated into internal calculations run by the collection system’s monitoring equipment
- If pressure was not incorporated into the internal calculations run by the collection system’s monitoring equipment, enter the average monthly pressure at which the landfill gas flow was measured (in atmospheres) for each month of the reporting year.

- Indicate whether landfill gas flow was measured on a wet or a dry basis and whether CH
_{4}concentration was measured on a wet or a dry basis- If landfill gas flow was measured on a wet basis and CH
_{4}concentration was measured on a dry basis, or gas flow was measured on a dry basis and CH_{4}concentration was measured on a wet basis, provide the monthly average moisture content (expressed as a decimal fraction) for each month of the reporting year.

- If landfill gas flow was measured on a wet basis and CH
- Indicate whether landfill gas destruction occurred at the facility (on-site), off-site, or both.

Please note that for reports submitted for reporting years RY2010 through RY2012, data detailing on-site destruction efficiency and operating hours are also collected on this page. For RY2013 and later, these data are collected on the Equation HH-4 Landfill Gas Measurement Locations Page.

When you have entered the information, click SAVE. You will be brought back to the top of the page at which time you may check over the information entered. When you have completed your check, click NEXT to be taken to the next page for equation information.

__Emissions Reporting Equations for Landfills with Gas Collection Systems__

Landfills that have a landfill gas collection system are required to report two sets of CH_{4} generation and CH_{4} emissions values. Many of the equations for deriving these values for Industrial Waste Landfills are the same as those used by Municipal Solid Waste Landfills under Subpart HH, per §98.463(b)(3) of the rule. The Subpart HH equations are referenced below, as appropriate. CH_{4} generation, adjusted for oxidation must be reported as calculated using both Equations TT-5 and HH-7, and CH_{4} emissions must be calculated using both Equations HH-6 and HH-8.

For each equation:

- Hover over an element in the equation to read a definition of that element as needed.
- The equation may be calculated by e-GGRT itself or by using a spreadsheet tool provided. Spreadsheets are also available for calculating inputs to the equations. For example, use the Subpart TT-1, TT-2/TT-3, and TT-4a/TT-4b spreadsheets to calculate inputs to Equation TT-6 as needed.
- If a spreadsheet tool is available for download on the page, download the spreadsheet tool by clicking the link labeled “Use TT-n or HH-n spreadsheet to calculate.”
- Fill in the spreadsheet completely using the instructions provided in the tool.
- After completing the spreadsheet, copy the value of CH
_{4}calculated by the spreadsheet to this page in the corresponding box. - On most equation pages, you will have the option to use the result calculated by e-GGRT or enter your own result by clicking on one of the following radio buttons at the bottom of the page:
- "Use the calculated result rounded"
- "Enter my own result (value will be rounded)", you click this radio button, you must enter an alternative value

Subpart HH is the subpart for Municipal Solid Waste landfills. The rule directly references Subpart HH for all monitoring requirements and calculations related to landfill gas collection systems at industrial waste landfills. If an industrial waste landfill has a gas collection system, the subpart HH equations must be followed to complete the methane generation and emissions calculations. The results of these calculations are then entered into the subpart TT module of e-GGRT.

There will be a series of pages for these equations. You will have to click the NEXT button to get to the next equation page or you can use the links in the gray box at the top of each page to hop from equation to equation.

CH4 Emissions (for Landfills With a Gas Collection System)

For RY2013 and later, after clicking the NEXT button, you will be brought to the "CH_{4} Emissions (for Landfills With a Gas Collection System)" page.

Please provide the Methane Oxidation Fraction for your landfill using the screen below. You must select from one of the values provided in the drop down menu. For assistance in determining the appropriate methane oxidation fraction from Table HH-4 of this subpart to use for your facility for each equation, please consult the Methane Flux Calculation Spreadsheet.

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Click NEXT to move on to the "Equation TT-1 Summary and Result" page.

Equation TT-1 Summary and Result

On this page, e-GGRT will calculate the modeled annual methane generation (G_{CH4}) in metric tons per year (the output of Equation TT-1) for each waste stream identified. e-GGRT will calculate your total annual modeled CH_{4} generation with Equation TT-1 by summing each waste stream-specific Equation TT-1 result, rounding the value according to e-GGRT rounding rules, and storing both the rounded and unrounded values in the database.

e-GGRT will also allow you to report the modeled annual methane generation (G_{CH4}) in metric tons per year (the output of Equation TT-1). To enter a value, click the "Enter my own result" button and enter your result in the box that shows up below the question. e-GGRT will store your estimated value of modeled annual methane generation (G_{CH4}) in metric tons per year (the output of Equation TT-1), round the value to the nearest metric ton, and store the rounded value and the facility-entered unrounded value in the database.

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Click NEXT to move on to the "Equation in Table HH-3 Summary and Result" page.

Equation in Table HH-3 Summary and Result

On this page, e-GGRT will calculate the estimated gas collection efficiency ("CEave1") using the equation provided within Table HH-3 to Subpart HH of Part 98 (Landfill Gas Collection Efficiencies) and round the result to two digits right of the decimal. If you have filled in the "Estimated Waste Depths" page, e-GGRT will pre-populate the "Equation in Table HH-3 Summary and Result" page for you and show a calculated result.

You may use this result or enter your own value by clicking the "Enter my own result" button. Enter your result in the box that shows up below the question. e-GGRT will store your estimated value, round the value to two digits to the right of the decimal, and store both the rounded and unrounded value in the database.

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Click NEXT to move on to the "Equation HH-4 Landfill Gas Measurement Locations" page.

Equation HH-4 Landfill Gas Measurement Locations

You are required to provide the annual quantity in metric tons of recovered CH_{4} calculated using Equation HH-4. Prior to RY2013, e-GGRT could not calculate this result because not all inputs to Eq. HH-4 were reported. For RY2012 and earlier, use the calculation spreadsheet link provided under the data entry box to do this calculation, and then enter the value into the box highlighted in red. e-GGRT will store your estimated value, round the value to the nearest metric ton, and store both the rounded and unrounded value in the database.

For RY2013 and later, the inputs to Eq. HH-4 have been added to the reported data elements. These inputs are collected through a series of pages that follow.

You must characterize each land fill gas measurement location. Start by clicking "ADD a Measurement Location".

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For each measurement location, you must identify the measurement location and provide an optional description for the location. In addition, for each measurement location you must provide:

- Annual quantity of recovered CH4 associated with that location
- Annual operating hours for the measurement location.
- Identify all destruction devices used to destroy recovered landfill gas from that measurement location.

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If you indicated that the collected landfill gas was destroyed either at the facility or both, the option to add a destruction device for each measurement location is made available. To add a destruction device associated with a given measurement location, click "Add a Destruction Device" to open the Destruction Device page. If multiple destruction devices are associated with one measurement location, the destruction devices must be added one at a time. For each destruction device associated with a measurement location, you must provide:

- Name or ID for each Destruction Device
- Annual operating hours for the destruction device
- Destruction efficiency used (report the lesser of the manufacturer’s specified destruction efficiency or 0.99).

If you indicated that the collected landfill gas was destroyed both on-site and off-site, you must provide the information mentioned directly above for the destruction devices located on-site. For the destruction devices that are located off-site, you should still add the destruction device and report the total hours in the reporting year (8760 or 8784 if it is a leap year) and report a value of 1 for the destruction efficiency. If you add a measurement location, but do not add an associated destruction device, a validation message will appear in your validation report and e-GGRT will make the assumption that the values for the destruction efficiency (DE) and the fraction of hours the destruction device associated with each measurement location was operating (f_{DEST}) for this measurement location are both 1. Reporting this information for the off-site destruction devices will eliminate the validation message.

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After adding the data supporting each measurement location and each destruction device associated with each location, click SAVE. Upon completion of these data, your Equation HH-4 Summary and Result show a summary of the Eq. HH-4 results for each measurement location and the total amount of recovered CH_{4} at the facility (Total R_{n}), as shown in the example provided below.

After adding a measurement location, f_{REC} is calculated from the value of the annual operating hours reported for that measurement location divided by the annual operating hours in the year (i.e., f_{REC} = annual operating hours/8760 [or 8784 if a leap year]).

If the collected landfill gas is destroyed on-site or both, the DE can be directly reported for each destruction device through each respective destruction device page. A destruction device can be added through a Measurement Location page. If more than one destruction device is associated with a given measurement location, the arithmetic average of the DE values for all destruction devices associated with a particular measurement location is presented. If all of the collected landfill gas is destroyed off-site, the option to add a destruction device is not made available and a value of 1 is shown in the Equation HH-4 summary table and used in the calculations.

The f_{DEST} is calculated from the value of the reported annual operating hours for a specific destruction device divided by the total hours in the year (i.e., f_{DEST} = annual operating hours/8760 [or 8784 if a leap year]). If more than one destruction device is associated with a given measurement location, e-GGRT may not be able to correctly calculate a value for f_{DEST }because the rule does not require the number of hours flow was sent to each destruction device to be reported. Therefore, when more than one destruction device is associated with one measurement location, e-GGRT assumes f_{DEST,n }= 1 and that value is shown in the Equation HH-4 summary table and used in the calculations.

Values for DE and f_{DEST }will only appear in the table if at least one destruction device has been associated with a specific measurement location.

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Click NEXT to move on to the "Equation TT-6 Summary and Result" page.

Equation TT-6 Summary and Result

On this page, e-GGRT will calculate the landfill's annual methane generation adjusted for oxidation using Equation TT-6. e-GGRT will then round the result according to e-GGRT rounding rules and store both the rounded and unrounded values in the database.

You may use this result or enter your own value by clicking the "Enter my own result" button. Enter your result in the box that shows up below the question. e-GGRT will store your estimated value, round the value to the nearest metric ton (integer), and store both the rounded and unrounded value in the database.

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Click NEXT to move on to the "Equation HH-6 Summary and Result" page.

Equation HH-6 Summary and Result

On this page, e-GGRT will calculate the landfill's annual methane emissions (the output of Equation HH-6), round the value according to e-GGRT rounding rules, and store both the rounded and unrounded values in the database.

You may use this result or enter your own value by clicking the "Enter my own result" button. Enter your result in the box that shows up below the question. e-GGRT will store your estimated value, round the value to the nearest metric ton (integer), and store both the rounded and unrounded value in the database.

Recall that Equation HH-6 is constructed so that the greater of the modeled methane generation rate from Equation TT-1 or the quantity of recovered methane from Equation HH-4, is used for the G_{CH4} term. e-GGRT automatically chooses the larger of the two. This is so that the result of Equation HH-6 is not a negative value.

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Click NEXT to move on to the "Equation HH-7 Summary and Result" page.

Equation HH-7 Summary and Result

On this page, e-GGRT will calculate the landfill's annual methane generation adjusted for oxidation (output of Equation HH-7), round the value according to e-GGRT rounding rules, and store both the rounded and unrounded values in the database.

You may use this result or enter your own value by clicking the "Enter my own result" button. Enter your result in the box that shows up below the question. e-GGRT will store your estimated value, round the value according e-GGRT rounding rules, and store both the rounded and unrounded value in the database.

Part 98 currently does not require a value for f_{REC} used in Equation HH-7 to be reported. e-GGRT automatically calculates a value for f_{REC} based on the fraction of hours the recovery system was operating at each measurement location. If you have multiple measurement locations at your facility, e-GGRT may not calculate a matching value for f_{REC} used in your calculations. Please review the value for Equation HH-7 calculated by e-GGRT and select "Enter your own result" if the results do not match.

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Click NEXT to move on to the "Equation HH-8 Summary and Result" page.

Equation HH-8 Summary and Result

On this page, e-GGRT will calculate the landfill's annual methane emissions (output of Equation HH-8), round the value according to e-GGRT rounding rules, and store both the rounded and unrounded values in the database.

You may use this result or enter your own value by clicking the "Enter my own result" button. Enter your result in the box that shows up below the question. e-GGRT will store your estimated value, round the value according e-GGRT rounding rules, and store both the rounded and unrounded value in the database.

Part 98 currently does not require a value for f_{DEST} or f_{REC} used in Equation HH-8 to be reported. e-GGRT automatically calculates a value for f_{DEST} and f_{REC} based on data provided by the reporter on the measurement locations and destruction devices at the facility. If you have multiple destruction devices at your facility or select both (at the facility and off-site) as the location where landfill gas is destroyed, e-GGRT may not calculate a matching value for f_{DEST or }f_{REC} used in your calculations. Please review the value for Equation HH-8 calculated by e-GGRT and select "Enter your own result" if the values do not match.

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Note for Equations HH-6, HH-7, and HH-8: The calculation spreadsheet file for Equations HH-6, HH-7, and HH-8 has several tabs which are appropriate for different numbers of destruction devices and monitoring/measurement locations at the landfill. Please consult the “Using Subpart HH Calculation Spreadsheets" help screens to ensure appropriate use of the various tabs.

When finished with the equation pages, click FINISHED on the "Equation HH-8 Summary and Result" page. This will bring you back to the emissions overview information page. You will see that the "Summary and Result" section of that page is filled in with the information stored from the equation pages.

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You will be allowed to elect to use either the rounded result of Equation HH-6 (as calculated and rounded by e-GGRT, unless entered by the user) or the rounded result of Equation HH-8 (as calculated and rounded by e-GGRT, unless entered by the user) to roll up into your total CO_{2} e emissions from facility subparts as required by 98.3(c)(4)(i). If you make no election, e-GGRT will use the larger of the two rounded values.

When you are satisfied with the information shown, click SAVE. You will be brought back to the top of the emissions overview information page at which time you may check over the information entered. When you have completed your check, click Subpart Overview to return to the Subpart Overview page.