Source: adapted from USGS Fact Sheet FS-068-98, June 1998.
Supply chains are part of complex material flow cycles that start with extracting renewable and nonrenewable resources, becoming part of the resource supply system. Through a forward logistics process, these resources are transformed by the manufacturing sector to become final consumption goods. All forward logistics processes generate wastes and discards that enter the reverse logistics cycle. What can be recycled will reenter the resource supply cycle, while what remains will be put into a sink, most commonly a landfill. The circular economy concept tries to establish sourcing, manufacturing, and distribution strategies that limit discarded goods and parts.