Environmental Engineering Reference
In-Depth Information
environment. A pig is economically attractive but not environmentally friendly and needs to
be redesigned to be promoted to a star, and a frog is environmentally friendly but the produc-
tion cost needs to be reduced (García-Serna et al., 2007).
The x/y plot presented in Figure 4.8 can be also used to compare the performance of differ-
ent products or alternatives. It is a useful tool to evaluate what alternatives to manufacture a
product are better and what products need improvement. For instance, alternative 4 is better
than 3, 3 is better than 2, and 2 is better than 1. For readers with further interest in the topic
recommended sources are Saling et al. (2002) and BASF's web site.
Ecological footprint with spider web diagrams
Spider web diagrams are well-known tools used for the representation of multidimensional
results in a single plot. In a spider web diagram, multiple series of values are plotted in axes
that irradiate from a center point. It is a useful tool to represent environmental data for the
purpose of comparison.
BASF has adopted spider web diagrams to represent the ecological fingerprint of products
or processes. As an illustration, a generic diagram is presented in Figure 4.9 that shows six
indicators of environmental performance and four generic processes.
In Figure 4.9, alternative 1 has been taken as a reference and for that reason its value is
standardized to 1.00. From this diagram, alternatives 2, 3, and 4 have the same impact on land
use and at the same time they are all better than alternative 1. Overall, alternative 4 is the best
option when comparing all indicators except for the factor of land use. Alternative 3 is better
than 2 for most of the factors except for emissions.
Energy
consumption
1.00
Materials
used
Land use
0.50
0.00
Risk
potential
Emissions
Toxicity
Alternative 1
Alternative 2
Alternative 3
Alternative 4
Figure 4.9
Spider web diagrams for six environmental indicators and four hypothetical alternatives.
Adapted from García-Serna et al., 2007.
