Highly integrated urban energy, water and waste systems

Urbanisation continues to bring socioeconomic well-being to an ever-growing global urban population. Nevertheless, there is an environmental and economic imperative for cities to use resources more sustainably. One way to achieve this is to take advantage of the fact that, in cities, resource management infrastructure from the energy, water and waste sectors is co-located, such that the wastes and by-products from one process become the inputs to another (for example, sending organic waste to anaerobic digestion to produce biogas for energy generation). This thesis helps planners and policy makers to begin realising these intersectoral synergies, through contributions to the field of urban metabolism. First, a conceptual model is developed which can describe how a city’s mix of processes affect is metabolism. Second, methods are needed which quantify how well different sectors work together to make an area’s metabolism more efficient; to that end, analysis on historic urban resource flows show the usefulness of exergy analysis and ecological network analysis. Third, data is required which shows the possibilities for one process’s wastes to become another’s inputs; for this, a database is assembled which records the resource consumption and production of various urban resource management process (made public under an open-source license). Fourth, the Processes, Resource and Qualities (PRaQ) model is developed; PRaQ is a mixed-integer linear programme which simultaneously chooses the mix of energy, water and waste management processes an area could use to minimise an objective (emissions, for example), thereby taking into account intersectoral synergies. Applying PRaQ to a new urban development in China shows how an area’s urban metabolism can be made measurably more efficient according to various metrics. In summary, this work advances the urban metabolism concept to support improvements to urban resource sustainability, by showing how a city’s mix of process affects its overall metabolic flows.Open Acces