5.3. & 5.4. PCSR 06-09-2009 - Laserfiche WebLink

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The site currently generates electricity from the methane gas extracted during the waste • degradation process. With the development of the SDA, the facility intends to add a second on- site electrical generation plant. The methane extraction system is developed with the landfill, and will continue operation after the landfill is final covered. The landfill gas extraction wells are constructed in accordance with industry standards. Depending on the selected end use plans for the site, modification of some of the gas extraction wells may be necessary, to locate the wellhead below grade. The modification will still allow access to the monitoring well for maintenance and monitoring, but will allow the well-head to be secured for the intended end-use. The SDA will be constructed in a series of phased construction projects. The timing of the projects will be dictated by incoming waste volumes and site operations. The following Table 1 indicates that anticipated SDA construction schedule based on current and anticipated waste volumes. Table 1. SDA Construction Phasing Cell Number Approximate Year of Construction Approximate Acres Constructed 18 2011 7.5 19 2013 7.5 20 2015 7.5 21 2017 7.7 22 2020 7.9 23 2022 8.1 24 2025 8.4 25A 2027 9.0 25B 2030 9.8 The Site Development Plan indicates the location of each of the phases of landfill development. Based on the above information and current waste flows, it appears that the final phase of the SDA will be constructed and closed during the time period from 2030-2033. 1.2.6 GRADING AND DRAINAGE PLAN The ERL has made it their priority to handle and control all stormwater generated on the SDA on- site. The grading and drainage plans are provided on the Subwatershed Map and Drainage Plan. The drainage calculations are presented in Exhibit 4. During the initial construction phases of the SDA, stormwater generated will be piped to an interim pond located south of the active cells. As construction and mining conditions dictate, permanent sedimentation basins will be constructed and put into service for treatment of runoff from the SDA. The sedimentation ponds will control and minimize the amount of sediment-laden runoff that leaves the SDA. If the designated area for the permanent ponds is not available, an equivalent sized temporary pond will be constructed in the mined area. Perimeter ditches of equivalent capacity to those shown on the final closure plans will route stormwater to the temporary ponds. • Elk River Landfill SDA ~ Section 1-6 Land Use Application «F^,~~~ ... , ~ Bonestroo ~WenCl<