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Industrial Ecology/Symbiosis. Metabolic Systems. What comes to mind when you think of a “metabolic system” or a “metabolism”?. Metabolic Systems. Cities as Metabolic Systems.
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Metabolic Systems What comes to mind when you think of a “metabolic system” or a “metabolism”?
Cities as Metabolic Systems It is however possible to conceive of entire communities of different geographic scales (e.g., cities, regions, nations) in similar metabolic terms.
Sydney Cities as Metabolic Systems In other words, we can view a city is if were a “living system” (e.g., a body, an ecosystem) that takes in certain raw materials, processes these inputs, and generates outputs (or waste products).
Cities as Metabolic Systems Contemporary cities (as well as regions and nations) are essentially linear metabolic systems. Inputs are drawn in, processed, and then released as wastes.
Entropy The problem is that linear systems are massively entropic.
What is Entropy? Entropy is the normal tendency for a system to go from a state of higher organization to a state of lower organization.
Entropy in Practice Materials with high levels of order (minimum entropy) are degraded as they move through a city (and have energy applied to them) and change into forms that have relatively low levels of order (maximum entropy).
Entropy in Practice A unit of unburned hydrocarbons (low entropy).
Entropy in Practice A unit of refined hydrocarbons.
Entropy in Practice A unit of burned hydrocarbons.
Law of the Conservation of Mass The concept of entropy reminds us of the Law of the Conservation of Mass.
Law of the Conservation of Mass The mass of an closed system cannot be changed as a result of processes acting inside the system. In perhaps more familiar terms, mass cannot be created or destroyed, although it may be rearranged in space, and changed into different types of particles.
Mass Balance of an Urban Metabolism Just as mass balances are calculated to represent specific chemical reactions, we can construct mass balances of how materials flow through a city.
Cities as Circular Systems We can also consider alternative, more sustainable urban models. One option calls for recreating cities as relatively closed loops, or circular, metabolisms.
Circular Economy in China This notion of a circular metabolism has—perhaps surprisingly—taken root most deeply thus far in China where there is a government commitment to creating a “circular economy.”
Industrial Ecology We tend to interpret environmental risks in terms of overt pollution generated by industrial sources and have developed elaborate regulatory systems to limit the adverse risks to which we are exposed.
Industrial Ecology United States
Industrial Ecology This is terribly inadequate and does not begin to help us to move in the direction of more sustainable modes of production and consumption.
Industrial Processes as Metabolic Systems We can apply the concept of a metabolic system to industrial processes.
Industrial Processes as Metabolic Systems 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 concert 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 product, to obsolete product, and to ultimate disposal. Factors to be optimized include resources, energy, and capital.
Industrial Ecology at Kalundborg One of the most interesting real-world examples of a relatively closed-loop industrial system is in the Danish city of Kalundborg.
Life Cycle Analysis One of the primary tools of industrial ecology is Life Cycle Analysis/Assessment (LCA).
Basic Example of Life Cycle Analysis LCA is an engineering accounting procedure to assess the full range of environmental impacts across the entire lifespan of a product.
Basic LCA Example Disposable vs Cloth (home launder) vs Cloth (commercially launder)
Basic LCA Example Disposable vs Cloth (home launder) vs Cloth (commercially launder)
Basic LCA Example Energy Sources
Toyota Yaris Toyota Prius LCA of an Automobile Hybrid vs. Conventional Fuel Vehicles
LCA of an Automobile Hybrid vs. Conventional Fuel Vehicles Environmental impacts of materials manufacture Environmental impacts of vehicle assembly Environmental impacts of vehicle use + Environmental impacts of disposal (e.g., component recoverability) ________________________________________________________ Total life cycle impacts
LCA of an Automobile Hybrid vs. Conventional Fuel Vehicles
More on Life Cycle Analysis http://www.sciencenetwork.com/lca/intro_overview.cfm
Principles of Industrial Ecology 1. Products, processes, services, and operations can produce residuals, but not waste.
Principles of Industrial Ecology 2. Every molecule that enters a specific manufacturing process should leave that process as part of a sellable product.
Principles of Industrial Ecology 3. Materials used should be the least toxic for the purpose, all else equal.
Principles of Industrial Ecology 4. Industries should get most of their needed materials through recycling streams rather than through raw materials extraction.