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<br /> <br />Forward Landfill – SIR 8 www.scsengineers.com <br /> <br />8 GAS CONTROL AND MONITORING SYSTEMS (GCCS) <br />The current GCCS consists of a system owned and operated by Forward, Inc. LFG is collected from <br />areas of the landfill with waste in-place 2 years or more at final grade and 5 years or more at interim <br />grade, respectively. Forward, Inc. system consists of vertical extraction wells and horizontal <br />collectors, a collection system consisting of corrosion resistant piping which is used to convey the <br />collected LFG, and a blower/flare station (BFS) used to destruct the collected LFG. The current GCCS <br />consists of two (2) flares, and have a combined maximum capacity of approximately 5,400 cubic feet <br />per minute (CFM). An LFG-to-Energy Facility (LFGTE) is also located on Site, which is owned and <br />operated by a separate entity. The LFGTE is owned and operates their own permits, separate from <br />the Site. The GCCS is designed to be expanded as waste fill operations proceed. The GCCS layout is <br />included as Figure 3. <br />As previously noted in Section 6 – Volumetric Capacity, a reduction in organic waste received at the <br />Landfill equates to a reduction in yearly airspace consumption and associated increase in the life of <br />the Landfill. No changes are anticipated to the GCCS design and monitoring practices at the Site. <br />Improvements events would continue to be performed at the Site to meet applicable regulations, <br />engineering standards and to address impacts resulting from organics intake reduction at the Site <br />through closure. <br />9 GAS GENERATION <br />9.1 LANDGEM MODEL <br />Based on historical and future waste disposal conditions, the peak LFG generation was estimated <br />using Equation 1 (referenced as equation 6 in 40 CFR §63.1959(b)(2)(ii)(C)(1)) in the United States <br />(U.S.) Environmental Protection Agency’s (EPA’s) LandGEM model. The LandGEM model requires that <br />waste intake be input for every year (past and future) to use Equation 1. Historic and future disposal <br />rates input to the LandGEM models were obtained from the following sources and based on the <br />following assumptions: <br /> Waste acceptance rates from historical Site records were used for 1954 through 2013; <br /> CalRecycle records were used for 2014 through 2021; <br /> A growth rate of 1.4% was used for 2022 tonnages through closure (2036); <br /> The closure year for the LandGEM was calculated by based on the site life calculations <br />presented in the JTD. <br /> <br />Based on the model outputs, the peak LFG generation, with a closure date of 2036, was expected to <br />occur in 2037 with a generation rate of approximately 7,955 scfm. <br />9.2 LANDGEM MODEL WITH ORGANIC DISPOSAL REDUCTION <br />SCS calculated the maximum expected gas generation flow rate from the Landfill as part of the SIR <br />using LandGEM. Historic and future disposal rates input to the 2022 LandGEM models were obtained <br />from the following sources and based on the following assumptions: <br /> Waste tonnages from 1992-2021 based on site records; <br /> An annual growth rate of 1.4% was utilized for 2022 and beyond;