Recovery of Materials and Energy from Urban Waste, Introduction

Some of the “wastes” generated by humanity can be transformed to useful resources by means of recycling (materials recovery) or thermal processing (energy recovery). The subject of resource recovery from the discards of society is an essential part of what has been defined by the United Nations as “sustainable development” (Brundtland Commission, 1983). Before the second half of the twentieth century, the consumption of materials and energy by humanity was a small fraction of what it is today. An example of the rapid growth in consumption is the use of copper, a metal that has been known since the beginning of history: A 1995 study by the author showed that more copper was consumed between 1945 and 1995 than in the preceding six millennia. In 2016, the author updated this graph by adding the copper consumption by 2015 (Fig. 1). Consumption of copper between 1995 and 2015 increased linearly to 23 million tons. In fact, if it were not for the increased rate of recycling, humanity...