Title: Design of horizontal trenches for leachate recirculation in bioreactor landfills using two-phase modelling

Authors: Krishna R. Reddy; Rajiv K. Giri; Hanumanth S. Kulkarni

Addresses: Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL 60607, USA ' Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL 60607, USA ' Department of Civil and Materials Engineering, University of Illinois at Chicago, 842 West Taylor Street, Chicago, IL 60607, USA

Abstract: Horizontal trenches (HTs) are the simplest form of leachate recirculation systems (LRSs), constructed by excavating a trench to a desired depth and length along the length of a municipal solid waste (MSW) landfill. The performance of HTs is mainly based on few empirical studies. Moreover, previous mathematical models often either considered the MSW as saturated than unsaturated or assumed incorrect MSW properties. Hence, those studies lack the accuracy needed for the efficient design of HT. In this study, parametric studies are performed to develop design charts for HTs considering real field MSW conditions. Heterogeneous-anisotropic MSW resulted in an increase in wetted width and area and a decrease in the pore pressures developed than homogeneous-isotropic waste. Normalised design charts are provided to estimate wetted width, wetted area and pore water pressure at steady-state for a given leachate injection rate, hydraulic conductivity and the dimension and location of HT from a LRS.

Keywords: moisture distribution; horizontal trenches; design charts; wetted areas; two-phase flow; pore water pressures; leachate recirculation; bioreactor landfills; flow modelling; municipal solid waste; MSW landfills; hydraulic conductivity.

DOI: 10.1504/IJEWM.2015.069962

International Journal of Environment and Waste Management, 2015 Vol.15 No.4, pp.347 - 376

Received: 09 Feb 2014
Accepted: 23 Dec 2014
Published online: 16 Jun 2015 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article