Numerous mathematical models have been developed to simulate processes
governing leachate occurrence and behaviour in landfills. The emphasi
s 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 methanogen
esis 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 assoc
iated with estimating model parameters that can adequately describe th
e complex biological, chemical, and physical processes in landfills. T
hey become increasingly useful as more field data are obtained and use
d for calibration and validation purposes. This paper presents a revie
w 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 techniqu
es.