The illustration left, shows, from top to bottom, 7 resource efficiency methods with decreasing cost-effectiveness and increasing environmental impact. (Click on the thumbnail for a more detailed version of this image).
Clearly the most desirable and value-creating approach is to remove the need for a resource, or to reduce or minimise use as far as practicable. The next method, to “re-source“, meets the remaining need with a material with a lowest ecological impact. We then get into how we handle waste. Reuse in the same process is better than recycling or “down-cycling” into a different process. If neither can be achieved, it may be possible to recover some part of the waste – for example converting embedded energy into heat by burning waste. The least desirable option is to reject or dispose of the waste into the environment.