Industrial metabolism : roots and basic principles

Terms such as "life cyele management," "industrial ecology," "industrial metabolism," and "industrial symbiosis" are common in the literature on enviwnmentally conscious production, but the precise definition of these concepts and the distinction between them varies with authors. For clarity on these topics, we wll present a brief review of the work done by authors who first proposed these disciplines of study and related concepts. We also intend to explain how industril ecology is embedded within the development of related disciplines. This approach is relevant because a multidisciplinary approach is followed in implementing industrial ecology. Because of its multidisciplinary character, the field that is covered by industrial ecology has been gradually extended to domains beyond its original concepts. Therefore, it might be useful to redefine industrial ecology while reconsidering the original definitions of this topic. The essential aspect in which industrial ecology differs from other approaches is in the comparison between the industrial system and the naturaJ ecological system. This comparison is not only of academic interest, but it is considered a tooI for the redesign of the industrial system on various levels of aggregation aimed at achieving i.ncreased sust.linability. Must of the industrial ecologists advocate the closing of the materials cycles as an essential path toward this end. The method of quantitative materials-and energy flow analysis - also called industrial metabolism, is the principal instrument for achieving this goal. Therefore, this chapter describes the basic concepts of industrial metabolism.