Biomedical Engineering Reference
In-Depth Information
100%
Final increment very costly
Contaminant
removal
efficiency
Cost-effectiveness decreasing exponentially
Removal very cost-effective
0%
Cost
100%
Final increment again very
costly
Contaminant
removal
efficiency
Cost-effectiveness again decreasing
exponentially
Innovative treatment technique
95%
Cost
Figure
10.2
Prototypical contaminant removal cost-effectiveness curve. In the top diagram, during the first phase, a relatively
large amount of the contaminant is removed at comparatively low costs. As the concentration in the environmental media
decreases, the removal costs increase substantially. At an inflexion point, the costs begin to increase exponentially for each unit
of contaminant removed, until the curve nearly reaches the steady state where the increment needed to reach complete removal
is very costly. The top curve does not recognize innovations that, when implemented, as shown in the bottom diagram, can make
a new curve that will again allow for a steep removal of the contaminant until its cost-effectiveness decreases. This concept is
known to economists as the law of diminishing returns
to achieve, i.e., a desired outcome, or something we would like to avoid, i.e., an adverse outcome. In
particular, engineering is “utilitarian,” to the extent that we are called upon “to produce the most good
for the most people.”
25
However, engineers are also duty bound to our codes of ethics, design criteria,
regulations, and standards of practice. In this way, engineering is a type of “deontology.”
26
Engineers
must, to the best of their abilities, consider all possible design outcomes, planned or otherwise. But this
is not easy because the most appropriate “benchmarks” for success in engineering projects are moving
