In situ characterization of temperature and gas production using membrane interface probe (MIP) and hydraulic profiling tool (HPT) in an operating municipal solid waste landfill

A modern Municipal Solid Waste (MSW) landfill is a renewable energy resource to produce a significant amount of heat and methane used for generating electricity. However, it is difficult to use those sources effectively because active and post-closure MSW landfills are heterogeneous spatially and temporally and exposed to complex environments with varying pressure and moisture in the landfill. With regard to the prediction of the sources, the analysis of in situ MSW properties is an alternative way to reduce the uncertainty and to understand complex processes undergoing in the landfill effectively. A Hydraulic Profiling Tool (HPT) and Membrane Interface Probe (MIP) measures the continuous profile of MSW properties with depth, including hydraulic pressure, temperature, hydraulic conductivity, electrical conductivity (EC), and concentration of selected volatile organic compounds and methane. In this study, we conducted a series of MIP with HPT tests to investigate the MSW characteristics of a landfill in Nebraska. The results of the test showed an increase in hydraulic pressure and temperature with depth. The EC profile showed a variety of different waste constituents and MIP results showed the methane trapped beneath the top cover. The results in terms of hydraulic properties, temperature and EC obtained from different sites can be used to estimate the waste age and help designing energy recovery systems.