Energy and material flow of waste-processing operations

Although waste continues to be produced in large quantities—the rate of increase in waste production being more or less in line with the rate of growth in the economy—society is still grappling with the problem of sustainable waste management. One of the best ways to assess sustainability is in terms of mass and energy balance. A project at the University of Southampton looked at the ‘energy footprint’ for waste management. The project brought together data from existing work on waste quantities, materials flow and mass balance studies for a range of materials including paper, glass, plastics, metals and organics. These data have been combined with information on the energy requirements for different types of collection and processing systems for reuse, recycling, recovery and disposal of such materials. Taking into account energy benefits from any of these options, the information has been used to produce an energy and materials balance, and the results show the energy footprint and materials output of the current waste management practices in Southampton. This work allows exploration of alternative methods and highlights areas where insufficient information is available, or where improvements in collection or processing technologies could have a significant impact on the final energy and material balance. The greater Southampton area was used as a case study, but the methods developed could be applied to other areas by modifying the input data