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From preface to “Materials and Energy Recovery from Urban Wastes”

The rapid growth of urban population and economic development since the middle of the nineteenth century has resulted in the annual generation of billions of tons of urban wastes. Since antiquity, such wastes were disposed in landfills. In modern time, this practice has become untenable because of the scarcity of land near urban centers, the environmental impacts of large-scale landfilling, and the need to conserve nonrenewable resources. Technology advances have made possible the enormous increase in materials and energy consumption; technology can also help mitigate the adverse effects of dealing with the discards of society: The “wastes”generated by humanity can be transformed to useful resources by means of recycling (materials recovery) or thermal processing (energy recovery). This is the subject of this volume and is an essential part of what has been defined by the United Nations as “sustainable development.”

An obvious example of what has been called the “ecological imperialism” of humanity over all other species is the massive transformation of greenfields and forests to landfills. In the past, landfills were located near population centers. In recent times, cities, like New York, have run out of landfill space and transport their wastes hundreds of kilometers away to mega-landfills. This is made possible by waste transfer stations, diesel trucks, and other technological equipment and also by the fact that cities are generally more affluent than the communities where the new mega-landfills are created. Currently, the global use of land for landfilling urban wastes is estimated at over one billion tons per year. If all urban waste landfills were located at one place, they would use up, each year and forever, a surface area of 100 km2, equivalent to the surface area of metropolitan Paris.