Daily Soil Cover: A Preliminary Study of its Impact on the Landfill of Municipal Solid Waste

Olayiwola Oni
2009 Journal of Applied Scienes Research   unpublished
The changes in the hydro-physical properties of a municipal solid waste (MSW) fill owing to an intermediate soil layer were studied. Key parameters, including dry density, drainable porosity, and saturated hydraulic conductivity of waste samples with and without an intermediate soil layer were measured in conventional test cells under increasing overburden stresses. Ravelling of the soil grains (SG = 2.65) into the underlying waste layer, estimated to be up to 50%, appeared to increase the
more » ... ty of the waste fill, in effect, decreasing its permeability. The waste-only fill was more permeable than waste incorporating a soil cover; however, this reduced with increased vertical stress applied to the fills. The measured and calculated values of the saturated hydraulic conductivity of the composite layered fill differed up to a factor of 100 at low vertical stresses. The moisture routing, undertaken with a modified Hydrologic Evaluation of Landfill Performance (HELP) model, suggests that the use of daily cover soil may reduce leachate drainage, thus increasing the degree of moisture saturation in waste fills. Further, waste fills with daily cover may drain leachate for a longer time and require closer spacing of basal drains. However, appropriate use of daily cover soil was found to benefit the sustainable practice of MSW landfilling.