Modelling the upgrade of an urban waste disposal system

The waste intermodal station of Clyde, in the city of Sydney, Australia, is in the heart of a complex network of terminals connected by road and rail to transport urban waste from its first collection to its final disposal. The amount of waste the network is projected to handle in 2015 will increase from about 340,000 tonnes/year in 2006 up to about 1.5 million tonnes/year, following population and consumption raise. The paper proposes a discrete-event model to represent Clyde Transfer Station (TS) and its relations with the other terminals. Such a model allows one to evaluate the effects of different expansion plans of the station structures as well as different policies of the collection service. The results show that, as often happens, a careful consideration of management alternatives can decrease the necessity of structural enlargement, which is normally much more expensive, if at all possible.