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Evapotranspiration covers for landfills and waste sites - Chapter 3

Chương này mô tả các tính chất của bãi chôn lấp bao gồm trong đó là sử dụng rộng rãi và lựa chọn thay thế để bao gồm các luận án thông thường. Một phần quan trọng của chương này là một bản tóm tắt của các phép đo hiệu suất cho bao gồm các bãi rác; CHÚNG Cung cấp Hướng dẫn Về rò rỉ thông qua cho phép bao gồm các bãi rác. 3,1 Bãi rác thông thường Covers Hầu hết các bãi chôn lấp bao gồm tại chỗ ngày nay là thông thường, bao gồm rào cản Bởi vì tiểu bang. | 3 Conventional and Alternative Covers This chapter describes the properties of landfill covers that are in widespread use and alternatives to these conventional covers. An important part of this chapter is a summary of performance measurements for landfill covers they provide guidance regarding allowable leakage through landfill covers. 3.1 CONVENTIONAL LANDFILL COVERS Most landfill covers in place today are conventional barrier covers because both state and federal regulatory officials have readily accepted them in the past. They include one or more barrier layers within the cover and they meet the presumptive requirements for containment. The intention is that the barrier should oppose the forces of nature and prevent water from moving downward in response to the force of gravity. A common misconception is that the barrier layers are impermeable this is seldom if ever true. The goal is that the conventional barrier landfill cover should provide protection for decades or centuries however they have actually been tested for a fraction of their intended life. This chapter provides an overview of barrier covers. Several authors provide indepth discussion of conventional landfill covers US EPA 1991 1993 1996 McBean et al. 1995 Ankeny et al. 1997 Koerner and Daniel 1997 Gill et al. 1999 Weand et al. 1999 . 3.1.1 RCRA Subtitle c Barrier Cover Conventional RCRA Subtitle C covers employ barrier technology and typically include five or more layers above the waste Figure 3.1 US EPA 1991 Koerner and Daniel 1997 . The top layer consists of cover soil that supports a grass cover to provide wind and water erosion control. The second layer is a drainage layer its purpose is to remove water that accumulates above the barrier layer. The barrier layer consists of either a single low-permeability barrier or two or more barriers in combination. The gas collection layer permits removal and safe disposal of gas trapped under the barrier. The foundation layer of variable thickness .