(2) Method
The indicator weights and scores for hazard evaluation or environmental risk
assessment of MSWLFs are determined using the analytic hierarchy process (AHP),
literature reference and expert scoring method.
(a) Indicator weights and scores
The AHP method is applied to determine the weights of MSWLFs hazard indicators, which involves threes steps: to establish the hierarchical structure; to construct
pairwise comparison matrixes; and to calculate the relative weight.
The weights of MSWLFs hazard indicators are calculated, as shown in
Table 3.2, and their scores are as shown in Table 3.3.
(b) Rating and evaluation
The hazard scoring equation for MSWLFs is established based on indicator weights
and scores:
S ¼ b 1 Y 1 þ b 2 Y 2 þ b 3 Y 3 þ b 4 Y 4 þ b 5 Y 5 þ b 6 Y 6
ð3:1Þ
Table 3.2 Weights of MSWLFs hazard indicators
Indicator
Y1
Y2
Y3
Y4
Y5
Y6
Weight
0.3130
0.2049
0.1707
0.1262
0.0993
0.0861
Table 3.3 Scores of MSWLFs hazard indicators
Landfill
volume
Landfill
period
Leachate
production
Landfill type
Seepage control
Leachate treatment
Y1
(Â10
4 m
3
)
Y2 (a)
Y3
(Â10
4 m
3
/
a)
Y4
Y5
Y6
! 50 10 <5
10 >10
10 Toxic
substance
10 Natural soils
10 No collection
system
10
40–
50
8
5–10 8
5–10
8
MSW
8
Clay seepage
control
5
Only
collection
system
4
30–
40
6
10–
15
5
1–5
6
MSW and
construction
waste
6
Single-layer
composite seepage
control
3
Collection
and
processing
system
1
20–
30
4
! 15 1
0.5–l
4
Rural solid
waste
4
Double-layer
composite seepage
control
1
20 2
0.5 2
Construction
waste
2
44
3 Rating and Evaluation of Pollution Source Intensity …