Permeability Index of Mechanically Biologically Treated Waste and Its Application in Bioreactor Landfills

Abstract

The hydraulic conductivity of waste is an important parameter that influences the design of leachate recirculation system in a bioreactor landfill. The hydraulic conductivity of waste varies with respect to depth and time in a landfill. These variations can be attributed to the settlement of waste, and the corresponding changes in the void ratio can be related to permeability. In this study, experiments were conducted to find the values of permeability index (Ck, the ratio of the slope of the void ratio—coefficient of permeability relationship) at four different placement densities of waste. The relation between the compression index (Cc) and Ck for waste is discussed. Estimation of permeability using Ck is presented and compared with the reported values in the literature. The effect of initial placement density of waste on the design of injection wells in a typical bioreactor landfill is presented to demonstrate the applicability of Ck and Cc values with the help of HYDRUS-2D simulations.