2012-09-06_REVISION - M2008070 (24)

Home Browse Search

Design and Operations Plan Western Gravel E & P Waste Disposal Facility October 24, 2011 Page 1 of 1 Waiver Request — Regulations Section 3.5.3(A)(1) Final Cover Permeability A waiver from CDPHE solid waste Regulations Section 3.5.3(A)(1) — regarding final cover permeability not exceeding that of the liner is requested in accordance with Section 1.5 of the Regulations. Information requested under Section 1.5.1 (A -E) of the Regulations is provided in D &O Plan Section 1 and for Regulations Section F in D &O Plan Sections 2 and 3. The intent of the Regulation is to prevent elevated head forces on the liner system that could compromise system integrity. The cell liner engineering design is considered very robust, consisting of not only a double synthetic HDPE liner but leak detection and leachate collection recovery systems (See Sections 3.4.4, 3.4.5, and 3.4.6). The leachate collection recovery system (LCRS) is designed to maintain less than a 12 -inch depth of leachate over the barrier layer and promote leachate transport from the most distant point of the system to the leachate removal system in less than a 12 month period assuming saturated flow. The LCRS is designed to operate in perpetuity and control head forces on the liner system. In addition, the LCRS will be accessible in order to remove additional head from the liner system. Final cover will be designed to minimize infiltration in order to reduce head forces on the liner system. In accordance with Regulation Section 1.5.2, the following information is provided. Because the double liner system is so robust, a final cover permeability that does not exceed or is not more permeable than the liner system is considered impractical if not impossible. The designed LCRS system will control head forces on the liner system and provide access for additional head removal and final cover will minimize infiltration. The final cover using more permeability than the liner system is deemed adequate for the intent of the Regulations. Therefore, WG proposes that benefits derived from meeting the standard do not bear a reasonable relationship to economic, environmental, or other factors particular to the facility. In addition, the requested waiver is consistent with purposes of the Act and Regulations, is not deemed to constitute a major variation from regulation requirements, and will not cause or allow violation of any air or water quality standard or federal or local restriction NWCC, Inc.