Sustainability relates with Economics, Society, and Environment. However, one common fact that links them all is the generation of waste. This chapter is divided into two: The first part analyses the current generation of waste as well as its treatment. The second intends to establish policies for the future treatment of waste or, better yet, for ceasing the generation of waste. This first part begins by raising some capital questions: What is waste? Which are the components of waste? Where is waste generated? and How is waste treated? The second part will deal with: Why is waste produced? and What is society doing to correct this problem? 2. 2 First part: Current generation and treatment of waste 2. 2. 1 What is waste? The dictionary defines ‘waste’ as something useless, unwanted, or defective and the word ‘by-product’ as something produced in an industrial or biological process in addition to the principal product. From the point of view of sustainability, the word ‘waste’ does not have that meaning as, though it may be unwanted, it is not something useless and is certainly not defective. Even if in a manufacturing process a product or part of it does not conform to the manufacturer’s quality specs, it does not thereby become waste, but is, rather scrap material that is usually brought back to its original state and then processed again.