Experimental study of the porosity and permeability of municipal solid waste

Abstract

Permeability is a very important parameter to evaluate the landfill gas (LFG) transport properties of municipal solid waste (MSW). Waste permeability is largely dependent on pore structure, which is affected directly by compression stress and degradation. In this article, laboratory tests were conducted to determine the permeability of MSW under different stresses and degradation phases. Test results showed that porosity and permeability values were in the range of 0.11–0.65 and 8.7 × 10−14–7.29 × 10−12 m2, respectively. The porosity of waste samples declined exponentially with the increase of compacted density and linearly with the increase in water content. Permeability decreased significantly with stress and degradation because of the increase in compacted density and finer particles of the waste, which led to low porosity of the samples. The influence of stress on permeability was in the scope of 1.6 × 10−12–3.7 × 10−12 m2, whereas porosity was 0.23–0.34. However, the effect of coupled stress and degradation on permeability was reduced to more than an order of magnitude. The power model was found to be suitable for fresh and degradation wastes, whereas Kozeny–Carman model was only suitable for old wastes. This study provides theoretical and practical significance for environmental pollution control and resource utilization of LFG in landfills. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1694–1699, 2017