Modeling leachate generation and transport in solid waste landfills

Numerous mathematical models have been developed to simulate processes governing leachate occurrence and behaviour in landfills. The emphasis of these models have generally been on estimating leachate quantity and quality in order to control its associated environmental impacts, particularly on ground and surface water pollution, enhance methanogenesis and landfill stabilization, and provide guidance in the design of leachate control, recirculation and collection systems. These models have been successful to a limited extent, more in estimating leachate quantity than its composition, because of inherent uncertainties associated with estimating model parameters that can adequately describe the complex biological, chemical, and physical processes in landfills. They become increasingly useful as more field data are obtained and used for calibration and validation purposes. This paper presents a review of mathematical models designed to simulate leachate generation and transport in municipal solid waste landfills. The paper also describes future needs and potential improvements to current modelling techniques.