Transitions - Sustainable Design: The Science of Sustainability and Green Engineering - page 121

risks to public health and the environment by utilizing technologies at this source
that are economically acceptable and based on applicable scientific principles and
sound engineering designs. Of course, if we are able to completely transition to
an alternative green process that does not generate the waste, our job would be
done.
In the case of an industrial facility producing hazardous waste as a necessary and
unpreventable by-product of a profitable item, as considered here, for example, the
engineer can take advantage of the growing body of knowledge that has become
known as life-cycle analysis. 11 In the case of a hazardous waste storage facility or
a spill, the engineer must take the source as a given and search for possibilities for
intervention at a later step in the sequence of steps, as discussed below.
Under the life-cycle analysis method of intervention, the environmental man-
ager considers the environmental impacts that could incur during the entire life
cycle of (1) all of the resources that go into the product, (2) all the materials
that are in the product during its use, and (3) all the materials that are avail-
able to exist from the product once it or its storage containers are no longer
economically useful to society. Few simple examples exist that describe how life
cycle analysis is conducted, but consider any of a number of household cleaning
products. Consider that a particular cleaning product, a solvent of some sort,
must be fabricated from one of several basic natural resources. Assume further
that this cleaning product is currently petroleum based. An engineer could inter-
vene at this initial step in the life cycle of this product, as the natural resource is
being selected, and consequently, the engineer could preclude the formation of a
source of hazardous waste by suggesting instead the production of a water-based
solvent.
Similarly, intervention at the production phase of this product's life cycle
and suggesting fabrication techniques can preclude the formation of a source
of certain contaminants from the outset. In this case the recycling of spent
petroleum materials could provide for more household cleaning products with
less or zero hazardous waste generation, thus controlling risks to public health and
the environment. Another example is that of cogeneration , which may allow for two
manufacturing facilities to colocate so that the “waste” of one is a “resource” for
the other. An example is the location of a chemical plant near a power generation
facility, so that the excess steam generated by the power plant can be piped to the
nearby chemical plant, obviating the need to burn its own fuel to generate the
steam needed for chemical synthesis. Another example is the use of an alcohol
produced from anaerobically treating a waste from one plant that is a source of a
reagent or fuel for chemical processes at another.
The design process must account for possible waste streams long before any
switches are flipped or valves turned. For example, a particular household cleaning
product may result in unintended human exposure to buckets of solvent mixtures
that fumigate the air in a home's kitchen or pollute a town's sewers as the bucket's