Mass Balance Technique
Material Cycles
Water Cycle
Carbon Cycle
Nitrogen Cycle
Sulfur Cycle
Oxygen Cycle
Industrial Use of Materials
Industrial Ecology
Industry as an Ecological System
Industry as an Economic System
Decision Making Techniques of Industrial Ecology
Internet Links
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Industry as an Ecological System

As the outlook changed from waste management as the environmental objective to pollution prevention, looking at the "ecology" of and industry in a group of industries began to be advanced. Graedel and Allenby, (1994) in the first textbook published on Industrial Ecology, writes:

"Industrial Ecology is the means by which humanity can deliberately and rationally approach and maintain a desirable carrying capacity, given continued economic, cultural, and technological evolution. The concept requires that an industrial system be viewed not in isolation from its surrounding systems, but in context with them. It is a systems view in which one seeks to optimize the total materials cycle from virgin material, to finished material, to component, to obsolete product, and to ultimate disposal. Factors to be optimized include resources, energy, and capital." (Graedel and Allenby)

The "deliberate", "internal" approach means that we need to understand the underlying science, technology and decision-making aspects so that each of these can be adjusted and the whole system optimized, not just for performance of the product to meet the needs of the user, but also to minimize the environmental damage caused by the life cycle of the product.

The systems approach would help us make a transition from thinking of industry solely as an economic system to a more holistic framing of the industry as an ecology, compatible with the ecology of nature.

In the unit on Ethical Systems, we discuss the gradual dawning of the philosophy of Industrial Ecology. (I.E.) The main focus of I.E. is to look at the whole system of production, use and disposal. The major focus of I.E., writes Ayres, is to:

"identify opportunities for reducing wastes and pollution in the materials-intensive sections by exploiting opportunities for using the low-value byproducts (i.e. wastes) of certain processes as raw materials for others. Technical feasibility is the primary criterion for initial consideration." (Ayres 6). This view is an engineering perspective.

A more global approach to Industrial Ecology (I.E.) would be to plan and carry out all industrial and related activities including consumer use, in a way as to minimize environmental harm, to think of ecology as a guiding principle for our economic-technological systems. Very briefly, the principles of nature's ecology are: cycling, a web of interaction and interdependence among parts; stability, and diffuse boundaries. These are discussed in more detail in the unit on Ecological Systems.

Student Exercise: What do these principles of ecology mean if we are to apply it to a particular industry? Take the example of paper or plastic and outline how that industry could go about applying these principles of nature's ecology.

Figure ___ shows a scheme of the entire industrial - ecological system as represented by Bob Ayres and Kneese in the early 1970's. It is a beautiful representation of this system. It shows the two basic inputs: sunlight incorporated into natural materials through photosynthesis, and minerals from the earth. Starting with those two inputs, and adding air and water, we get quite a complex system of materials and energy in our industrial society. Note the large amounts of "residuals", or wastes.



Figure IE1. Scheme of Industrial - Ecological System


This flow of materials and energy is called Industrial Metabolism, taking the analogy from biology. "Metabolism" of materials in industry uses energy, labor, capital and information or knowledge.

Putting all these ideas together, we have a new framework for the ecology of industry. In the book Ecology of Industry [link], Deanna Richards and Robert Frosh introduces this idea with the following statement.

"...industry's ecology is defined by the metabolism of materials (the flow of materials through industrial systems, including their transformations during flow); the use of energy, labor and capital; and the application of information or knowledge. A characteristic of ecological systems is that they evolve. The evolution of industrial systems and their use (and storage) of resources are affected by the introduction of new technologies, decisions made in design, preferences of consumers, regulating dictates, and the like...Indeed "industrial ecology" has become jargon for describing systems of production and consumption networks that have a minimal impact on the environment as a primary objective and have an overarching objective of environmentally sustainable economic expansion."
  -Deanna J. Richards and Robert A. Frosch in The Ecology of Industry






  ©Copyright 2003 Carnegie Mellon University
This material is based upon work supported by the National Science Foundation under Grant Number 9653194. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.