Estimation of landfill properties through simulation

Abstract

The total content of dry substance (DS) and readily biode gradable material (RBM) in waste streams directed to six landfill test cells were estimated. These estimates were neces sary for the evaluation of the performance of the test cells and were used to both express methane production rates on a dry matter basis, and to obtain a measurement related to acido genesis. A hierarchial description of the test cell content was used for the calculation of DS and RBM. Test cells were treated as mixtures of different waste streams, and these, in turn, were divided into composite materials, each of which was assigned values of the emphasized properties; DS and RBM. A variety of information sources (entrance registra tions, sortmgs, visual inspections and estimates of waste stream fractions) were utilized and a method, which included both matrix calculations and simulation, was developed which included the standard deviation (SD) of each fraction. In this way, SD values for the total content of DS and RBM could be quantified. Exaggerations of the SD of estimated fractions affected the results to only a limited extent since the dispersion was leveled out by the multitude of compounds. The SD of the total content of DS and RBM were, therefore, sufficiently low to produce useful results. In comparison to the moisture contents measured after the final covering of the test cells, the results indicate that the material was dried during construction.