Transitions - Sustainable Design: The Science of Sustainability and Green Engineering - page 122

liquid is flushed down a drain. In fact, millions of dollars are spent on pretreatment
systems in municipal plants to remove such chemicals that will kill the beneficial
microbes that do the work in cleaning waste-water. In this way, life-cycle analysis
is a type of systems engineering where a critical path is drawn and each decision
point is considered.
Using a sustainable design approach (e.g., design for the environment) re-
quires that the disposal of this solvent's containers must be incorporated as a
design constraint from a long-term risk perspective. The challenge is that every
potential and actual environmental impact of a product's fabrication, use, and
ultimate disposal must be considered. This is seldom, if ever, a “straight-line
projection.”
Intervention at the Point of Release
If the pollutant release is not completely eliminated early in the life cycle,
the next step is to intervene at the point at which the waste is released into
the environment. This point of release could be at the top of a stack or vent from
the source of pollution to a receiving air shed, or it could be a more indirect
release, such as from the bottommost layer of a clay liner in a hazardous waste
landfill connected to surrounding soil material. Similarly, this point of release
could be a series of points as a contaminant is released along a shoreline from a
plot of land into a river or through a plane of soil underlying a storage facility
(i.e., called nonpoint source ).
Intervention as a Contaminant Is Transported in the Environment
Wise site selection of facilities actually occurs early in the life cycle. For facilities
that generate, process, and store contaminants it is the first step in preventing
or reducing the likelihood that pollutants will move. For example, the distance
from a source to a receptor is a crucial factor in controlling the quantity and
characteristics of waste as it is transported.
Meteorology is a primary determinant of the opportunity to control atmo-
spheric transport of contaminants. For example, manufacturing, transportation,
and hazardous waste generating, processing, and storage facilities must be sited
to avoid areas where specific local weather patterns are frequent and persistent.
These avoidance areas include ground-based inversions, elevated inversions, valley
winds, shore breezes, and city heat islands. In each of these venues, the pollutants
become locked into air masses with little or no chance of moving out of the re-
spective areas. Thus, the concentrations of pollutants can quickly and greatly pose
risks to public health and the environment. In the soil environment the engineer
has the opportunity to site facilities in areas of great depth to groundwater as well