Environmental Engineering Reference
In-Depth Information
Table 9.5
Multi-criteria evaluation matrix and weighting rating system for options evaluation according
to criteria.
Risk
Economic Economic
reduction
Emission
costs
benefits
technology
Technological Environmental
from the
(energy,
(future
Health Social Weighted
alternatives
efficiency
efficiency
technology duration) utilization) benefit benefits average
“0'' option
0
0
0
4
0
0
0
0.08
Doing nothing
Dig and
5
0
3
1
10
5
8
4.05
dump
Pump and
2
3
8
3
4
5
4
4.25
treat
In situ
6
7
8
10
7
7
5
7.60
bioventilation
Enhanced
8
8
9
7
9
8
6
8.1
in situ
bioventilation
In situ
8
6
9
7
9
9
7
7.8
chemical
oxidation
Weighting
10%
20%
20%
20%
20%
5%
5%
100%
percentage
for criteria
0: maximum negative impact; 10: maximum positive impact.
meaning in practice that the table containing the columns of criteria and the rows of
measures (this is the so-called impact scoring matrix, see Table 9.5) must not con-
tain empty cells, i.e. neutral, missing or insignificant impacts. Every stakeholder
fills out one matrix with quantitative or verbal descriptions;
-
A descriptor is required to each criterion
, e.g., “technological efficiency is the RR
rate, calculated from the eliminated percentage of the contaminant within one
year.'' The evaluation team should determine the weight of the criteria, given in
percent as shown in Table 9.5 and the scoring scales (e.g., 0-10) for every criterion
with accurate rating. In the example the eliminated percentage of the contaminant
is rated as follows: 10%: 1; 20%: 2; 30%: 3, etc. The qualitative rating of the
social benefits, e.g., residential services and recreation: present status: 0; useable
for commercial services within 1 year: 4; usable for residential services in one year:
8; usable for residential services and recreation in one year: 10, etc.;
-
Analysis of the impacts
of the alternative measures combining quantitative estima-
tion and qualitative description of the impacts. Evaluation criteria and measures
are organized into a multi-criteria evaluation matrix. Two methods are widely
used:
◦
Compensation method
attributes a weight to each criterion (last row in the
table), then calculates a global score for each measure in the form of a weighted
arithmetic average of the scores. Contradictory criteria may compensate each
other, and this may result in no difference between the alternatives;
◦
Outranking method
is used where the criteria are not commensurable, i.e.,
one criterion takes priority over another. The analysis is based on multiple
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