In the developed world, 75% of the population live in urban areas, a figure projected to rise to nearly 83% by 2030, while in the developing world, the rate of urbanisation is even faster. One of the most important environmental problems associated with urbanisation is the amount of waste that is generated at a rate that outstrips the ability of the natural environment to assimilate it and authorities to manage it. If, therefore, we are to deliver a more sustainable economy, we must do more with less by making better use of resources and putting these materials to good use. The use of municipal solid waste to produce energy or fuel is not only an important waste treatment option in itself but it also cuts down on the use of fossil fuels and hence can help meet renewable energy targets, address concerns about global warming and contribute significantly to achieving Kyoto Protocol commitments. This paper reviews the state-of-the-art technologies used in the thermal treatment processes of waste including com...