The Greening of Industrial Ecosystems (1994) / Chapter Skim
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Industrial Metabolism: Theory and Policy
Industrial Metabolism: Theory and Policy
Pages 23-37
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From page 23... ...
The process also necessarily involves excretion or exhalation of waste outputs, consisting of degraded, highentropy materials. There is a compelling analogy between biological organisms and industrial activities- indeed, the whole economic system not only because both are mater~als-processing systems driven by a flow of free energy (Georgescu-Roegen, 1 971 )
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From page 24... ...
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From page 25... ...
It keeps financial accounts for all its external transactions; it is also relatively easy to track physical stocks and flows across the "boundary" of the firm and even between its divisions. THE MATERIALS CYCLE A third way in which the analogy between biological metabolism and industrial metabolism is useful is to focus attention on the "life cycle" of individual "nutrients." The hydrological cycle, the carbon cycle, and the nitrogen cycle are familiar concepts to earth scientists.
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From page 26... ...
A closed system becomes a closed cycle if the system is also in steady-state, that is if the stocks in each compartment are constant and unchanging, at least on the average. The materials balance condition implies that the material inputs to each compartment must be exactly balanced (on the average)
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From page 27... ...
short of ultimate thermodynamic equilibrium that could be reached with the help of a feasible technological "fix"?
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From page 28... ...
the oxygen generated by anaerobic photosynthesis was captured by dissolved ferrous iron molecules, and sequestered as insoluble ferric oxide or magnetite, with the help of another primitive organism, the stromatolites. The resulting insoluble iron oxide was precipitated on the ocean bottoms.3 (The result is the large deposits of high-grade iron ore we exploit today.)
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From page 31... ...
steady-state industrial economy would necessarily be characterized by near-total recycling of intrinsically toxic or hazardous materials, as well as a significant degree of recycling of plastics, paper, and other materials whose disposal constitutes an environmental problem. Heavy metals are among the materials that would have to be almost totally recycled to satisfy the sustainability criterion.
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From page 32... ...
In fact, it is easy to verify that most chemical products belong in the third category, except those physically embodied in plastics, synthetic rubber, or synthetic fibers. From the standpoint of elements, if one traces the uses of materials from source to final sink, it can be seen that virtually all sulfur mined (or recovered from oil, gas, or metallurgical refinenes)
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From page 33... ...
It follows from materials balance considerations that sulfur is entirely dissipated into the environment. Globally, about 61.5 million metric tons of sulfur as sulfur not including gypsum were produced in 1988.
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From page 34... ...
For lead, the ban on using tetraethyl lead as a gasoline additive (an inherently dissipative use) is entirely responsible.
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From page 35... ...
It is a consequence of the law of conservation of mass that the total quantity of materials extracted from the environment will ultimately return thence as some sort of waste residuals or "garbojunk" (Ayres and Kneese, 1969, 19891. Yet environmental protection policy has systematically ignored this fundamental reality by imposing regulations on emissions by medium.
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From page 36... ...
In fact, there is a tendency for suboptimal choices to get "locked in" by widespread adoption. Large investments in so-called clean coal technology would surely extend the use of coal as a fuel an eventuality highly desired by the energy establishment but would also guarantee that larger cumulative quantities of sulfur, fly ash (with associated toxic heavy metals)
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From page 37... ...
A major materials substitution within a sector can result in the use of one material increasing, at the expense of others, of course. The substitution of plastics for many structural materials, or of synthetic rubber for natural rubber, would exemplify this sort of substitution.
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