Wastes generated in a community can be a valuable energy and material resource. However, past and current waste disposal and treatment practices consume energy and have led this resource to become a serious environmental burden. Fortunately, being a resource as well as a burden has generated some extremely creative and economically attractive waste-to-energy systems to utilize wastes while mitigating their environmental impact. It is hoped that this book will promote an appreciation of the environmental problems, energy demand and resources, the economics and risks involved that are essential to define the role of these systems in the future. The problems of urban air pollution, acid rain, global greenhouse effect and surface and groundwater degradation all can be tied directly or indirectly to how we produce and utilize energy and dispose of wastes. All communities have wastes, be they wastewater, municipal solid wastes, industrial or agricultural wastes, and the community must deal with them. It is possible to consolidate many of these wastes to gain real benefits in terms of the environment, economics, energy supply and conservation and materials recovery. This text summarizes s