Numerical Evaluation of Landfill Stabilization by Leachate Circulation

This study compares various leachate management scenarios using a biologically reactive transport model, which is proposed in this study. The proposed model can be used to predict the contribution of biodegradation to contaminant attenuation and contaminant concentration in leachate over time. It can also be used to assess the extent of landfill stabilization in terms of local mass per bulk volume of remaining refuse available for transfer. A sensitivity analysis shows that landfill stabilization has significant sensitivity to most biokinetic parameters, the fluid-phase saturation constant, and the dissolution rate, in addition to the half-saturation constant and the retardation factor. The proposed model is applied to assess landfill stabilization under two control scenarios: leachate recycling versus continued input of clean water with no recirculation. The simulation results indicate that leachate recirculation provides more favorable conditions for development of an active anaerobic bacterial population and, hence, accelerates landfill stabilization.