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Appendix C - LandGEM - Forward_1954 2033 (Part 1)12/29/2022 <br />Summary Report <br />Landfill Name or Identifier: Forward Landfill LandGEM (1954 - 2033) <br />Date: <br />First-Order Decomposition Rate Equation: <br />Where, <br />QCH4 = annual methane generation in the year of the calculation (m 3 /year ) <br />i = 1-year time increment Mi = mass of waste accepted in the ith year (Mg ) <br />n = (year of the calculation) - (initial year of waste acceptance) <br />j = 0.1-year time increment <br />k = methane generation rate (year -1 ) <br />Lo = potential methane generation capacity (m 3 /Mg ) <br />tij = age of the jth section of waste mass Mi accepted in the ith year <br />(decimal years , e.g., 3.2 years) <br />LandGEM is considered a screening tool — the better the input data, the better the estimates. Often, there are limitations with the available data <br />regarding waste quantity and composition, variation in design and operating practices over time, and changes occurring over time that impact <br />the emissions potential. Changes to landfill operation, such as operating under wet conditions through leachate recirculation or other liquid <br />additions, will result in generating more gas at a faster rate. Defaults for estimating emissions for this type of operation are being developed to <br />include in LandGEM along with defaults for convential landfills (no leachate or liquid additions) for developing emission inventories and <br />determining CAA applicability. Refer to the Web site identified above for future updates. <br />Thursday, December 29, 2022 <br />LandGEM is based on a first-order decomposition rate equation for quantifying emissions from the decomposition of landfilled waste in <br />municipal solid waste (MSW) landfills. The software provides a relatively simple approach to estimating landfill gas emissions. Model defaults <br />are based on empirical data from U.S. landfills. Field test data can also be used in place of model defaults when available. Further guidance on <br />EPA test methods, Clean Air Act (CAA) regulations, and other guidance regarding landfill gas emissions and control technology requirements <br />can be found at http://www.epa.gov/ttnatw01/landfill/landflpg.html. <br />Description/Comments: <br />Tonnages for 1954 thorugh 2022 based on site records. The projected waste disposal quantities assume a 1.4% growth <br />rate. Waste tonnage in 2025 was calculated by taking the estimated 2025 tonnage and subtracting 407,674 tons, which is <br />75% of the organic waste disposed in 2014. A closure date of 2043 was utilized based on the remaining volumetric <br />capacity. <br />About LandGEM: <br />REPORT - 1