Leachate Collection System Performance Analysis

Abstract

The sensitivity of a waste disposal impoundment's leachate collection system performance to a range of design parameter values is investigated based on a computer modeling study. The piezometric head distribution in a vertical cross section of the impoundment is simulated using the finite element method to solve the combined equation of motion and continuity for two‐dimensional flow through a saturated anisotropic porous media. The design parameters studied include saturated waste depth; ground slope; underdrain spacing; and the hydraulic conductivities of the waste, clay liner, drainage blanket, and drain filter. The emphasis in this investigation is on the effect of the design parameters on the hydraulic pressure distribution directly above the clay liner which underlies the waste. The results of the study indicate that the three key parameters controlling the hydraulic pressure on the liner are the underdrain spacing and the hydraulic conductivities of the underdrain filter and the drainage blanket between the waste and clay liner.