Artesian Landfill Liner System: Optimization and Numerical Analysis

Abstract

Conventional landfill design attempts to control the downward seepage of leachate by using low permeability liners. The rate of leachate seepage into the underlying ground-water system can be controlled by decreasing the permeability of soil liners and/or by using synthetic membranes to form an additional barrier to leachate migration. However, loss of leachate from conventional landfills is likely to occur due to the inherent limitations of natural materials and the inevitable imperfections of installing synthetic liners. The artesian landfill liner system eliminates the downward seepage by reversing the direction of the hydraulic gradient so that seepage occurs into, and not out of, the landfill. A conceptual cost model incorporates the trade-offs between the capital cost of constructing robust liners and the operational costs of supplying recharge water and treating additional leachate produced by the artesian hydraulics. In addition, a two-dimensional, transient finite-element flow model demonstrates that the reverse hydraulic gradient limits the loss of leachate even if the integrity of the landfill liner is imperfect or deteriorates over time.