Quantitative Comparison between Settlement Observed in MSW Biodegradation and Sand-Salt Dissolution Tests

The in situ and laboratory MSW biodegradation is a long-term process, thus the assessment of its performance can be arduous. A sand-salt mixture is often used to replace an MSW specimen for simplification or approximation, with dissolution representing biodegradation. However, the effectiveness of this approximation still needs to be confirmed, and the effects of the initial properties and test conditions such as unstable fraction, size ratio, initial compaction, and vertical stress on the accuracy of this approximation are unknown. In this study, supplementary dissolution tests of sand-salt mixtures are first conducted to construct a dataset for sand-salt mixtures and MSW specimens. Then, the settlement, one of the most important characteristics in practice, is chosen to be the indicator to compare the suitability of this approximation based on test groups with different unstable fractions, while the effects of other initial properties and conditions are also investigated. Overall, the effectiveness of the approximation largely depends on the biodegradable fraction and salt fraction, while other properties only pose limited effects.