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Ms. Polly Kratman 17 January 2007 Page 2 approximately 38 acres in total footprint, has a 60-mil thick high-density polyethylene (HDPE) geomembrane single liner. The Infill Area has : (i) a single composite liner comprised of a 60- mil thick HDPE geomembrane placed on top of 2-ft thick compacted clay liner over a 5 -acre area between Segment 1 and Segment 2; and (ii) a 60-mil thick textured HDPE geomembrane single liner over the 7 . 5 acres of the eastern side slopes of the closed Segment 1 landfill . Leachate from the lined Segment 1 eastern side slopes, Segment 2, and Infill Area is collected through a combination of leachate collection system (LCS) drainage media and HDPE pipes, and conveyed to a pump station located at the northwest corner of Segment 2 . The leachate is then transferred through a force main to the West Regional Wastewater Treatment Plant for treatment and disposal. GeoSyntec also understands that the IRCL facility is currently regulated under the New Source Performance Standards (HSPS) for municipal solid waste (MSW) landfills as identified in Subpart WWW of 40 CFR, Part 60 (Subpart WWW) . The NSPS states that MSW landfills that exceed certain size thresholds (waste-in-place of more than 2 . 5 million Mg or 2. 5 million m3) or emission thresholds (emissions of non-methane organic compounds of greater than 50 Mg/yr) are required to collect and control its landfill gas . Currently, the IRCL does not exceed the thresholds prescribed by NSPS ; however, the IRCL has an active gas collection system in place, which includes 40 vertical gas collection wells and 13 horizontal gas collectors. The SWDD would like to implement a GCCS design that accounts for the future waste placement that will occur in the existing Segment 1 , Segment 2, and Infill Area and ties into the existing GCCS . In June 2005 , the Florida Department of Environmental Protection (FDEP) issued the SWDD with an expansion permit for the disposal of C&D debris over the south and west slopes of the closed Segment 1 landfill using 3 horizontal to 1 vertical (3H : 1 V) side slope geometry. The westward top slopes of the C&D expansion would extend to elevation (El .) 129 . 5 ft National Geodetic Vertical Datum (NGVD) and grade to the east at a 5 percent slope . The Segment 2 and Infill Area were also permitted to have 3H : 1 V waste slopes from El . 55 to El . 140 ft NGVD. In August 2006, FDEP issued the SWDD with an expansion permit for placement of C&D debris over the north slope of the closed Segment I landfill using 3H : 1 V side slope geometry, extending the elevation to approximately 125 ft NGVD . The C&D debris placement over the slopes of the previously-closed Segment 1 landfill would reach final grades by January 2008 and thereby requiring closure in accordance with the FDEP solid waste regulations. However, in order to improve aesthetics at the IRCL facility, the SWDD has voluntarily elected to place cover soil and sod over portions of the C &D debris that had reached final grades in a "close-as-you-go" manner. This temporary closure system will have to be verified and certified to meet the closure requirements of the solid waste regulations. XL06230.%01 -17-2007 1L70002 .doc en ineer5 I scientists I innovators