Byproducts of chemical processes should therefore be recovered and used again in other processes.
Water contaminated by one process should be safely recycled for use in others, ideally returned to the
natural world in a cleaner state than when it entered industry. Examples of the “waste is food” product
design concept listed on McDonough's website include a form of nylon, called Nylon 6, which can be
de-polymerized and re-polymerized with a 99 percent energy and material recovery rate, as
chemicals firm BASF has done.39