Experimental analysis of municipal solid waste samples

Abstract

In the analysis of municipal solid waste consolidation, large-scale devices are usually used to measure the compression and hydraulic conductivity parameters. The use of those devices is justified due to difficulties in probing undisturbed samples and the heterogeneity of the sample recovered. In this thesis, an experimental analysis was performed to compare consolidation, compression and permeability parameters of municipal solid waste samples resulting from different scale experimental devices. Two different scale devices were tested: the standard device used for consolidation in soils and a large-scale device constructed for the present investigation. A municipal solid waste sample was obtained from a pit dug in the College Station, Texas landfill. The large-scale and the standard-scale cells were filled with the oldest available municipal solid waste from the sample, which were estimated to be 10-years old. The specimens were subjected to known pressures simulating layers of 10 to 30m deep refuse fixed for 2 to 15 days. A falling head permeability test was conducted during the application of the known pressures, which simulate actual over burden conditions of the refuse in a landfill. The scale-effect in the consolidation behavior is significant. However similar behavior between the large-scale and the standard-scale test is observed. Permeability tests in large-scale cells are required to adequately describe hydraulic conditions in the field. Further testing of more scale devices is recommended to establish the optimum scale to obtain realistic parameters. More time for testing is also recommended to take into account degradation of the refuse. Consolidation behavior results provide justification for further work in this area. Conducting a larger set of experiments to establish a scale factor relating large-scale to small-scale devices is needed.