Provisional equations for determining leachate leakage rate through composite barriers from compromised geomembrane

Abstract: From years ago to present date the equations available for determining the rate of leachate leakage through composite barriers from geomembrane (GM) failures necessitated the use of graphs to attain the value of one of the terms of the equations for the case where the leachate head is larger than the thickness of the low-permeability soil medium of the composite barrier. This work reveals that the terms requiring graphs can be expressed analytically, which shows a new set of equations that leads to an entirely analytical approach of determining the rate of leachate leakage through composite barriers. The provisional set of equations is principally beneficial when the leachate level is large as against the thickness of the low-permeability soil medium of the composite barrier. This is usually the case when the low-permeability soil medium allied with the GM to form a composite barrier is a geosynthetic clay liner (GCL). Whether the failure in the GM is small or large or where the leachate level on top of the barrier is large as against the thickness of the low-permeability soil layer of the composite system, a provisional equation can be used to determine the leakage rate through the system. Although in such a scenario, graphs are essential in attaining the value of one of the terms of the equations. Therefore, this paper shows that the graphs can be replaced by equations, which proceeds to the generation and utilization of an entirely analytical method of determining the rate of leachate leakage through a failed composite waste containment barrier, irrespective of the leachate level overlying the system