Prediction of Waste Settlement in Bioreactor Landfills Incorporating Waste Biodegradation

Only a few attempts of modeling settlement behavior of bioreactor landfills are reported in the literature. The use of soil compression based models to estimate the waste settlement in bioreactor landfills is questionable as waste decomposition influences waste settlement rates. Though these models may provide satisfactory prediction of settlement, several fundamental deficiencies were observed. A new model was proposed by considering the first-order reaction kinetics of waste biodegradation. Due to the absence of waste properties needed for detailed calculations, the new model was modified to a single equation that contains two model parameters. The simplified version of the model was validated using reported data from four pilot studies; two of them were laboratory lysimeter studies while the other two were field scale bioreactor landfills. The proposed model provided better settlement predictions especially the long-term performance of all four cases, when compared with the conventional that based on soil compression models.