Environmental Engineering Reference
In-Depth Information
Table 10.3 Contaminant properties and calculated attenuation factors for Case study 2.
Calculated results
TPH
Benzene
Toluene
Ethylbenzene Xylene
Average half-life in soil (days)
30
30
90
30
300
Average half-life, water (days)
12
15
5
15
25
Average half-life, air (days)
2
7
1
5
1
log K ow
3-8
2.1
2.6
3.1
3.0
log K oc
3-7
2.1
2.1
2.7
2.1
AF biodegradation (pessimistic)
4
4
1.5
4
1.2
AF biodegradation (greatly pessimistic)
2
2
1
2
1
AF partition (pessimistic)
40
25
40
50
40
AF partition (greatly pessimistic)
4
2.5
4
5
4
DF (dilution factor in the soil)
2.5
2.5
2.5
2.5
2.5
AF aggregated (pessimistic)
400
250
150
500
120
AF aggregated (greatly pessimistic)
20
12.5
7.5
25
24
Measured initial concentration ( µ g/L)
8350
7330
11 000
1110
8300
Calculated concentration in the creek
21
30
73
2.2
70
inflow point (pessimistic) ( µ g/L)
Calculated concentration in the creek
420
586
1467
44
346
inflow point (greatly pessimistic) ( µ g/L)
Intervention value for ground water ( µ g/L)
600-2000
20-30
80-130
80-150
70-80
Calculated concentration in the creek
1.0
1.5
3.6
0.1
3.5
(pessimistic) ( µ g/L)
Calculated concentration in the creek)
20
29
73
2.2
17
(greatly pessimistic) ( µ g/L)
WQC for surface waters ( µ g/L)
600
600
180
50
200
(ANZECC, 2000)
WHO drinking water EQC ( µ g/L)
10
700
300
500
(WHO, 2008)
-
The calculated time necessary for the advection of the plume from source to creek
is about 100 days. Partition between soil solid and liquid and half-life in soil are
the most influencing properties of the contaminant constituents, while soil organic
matter content and soil microbial activity are significant parameters concerning
the soil. As partition and degradation take place only on the plume's surface, its
geometry, the surface-volume ratio influence attenuation to a large extent.
-
Dilution factor (DF) calculated by hydraulic modeling based on equation [2] due
to transversal water flow from the source toward the creek in the plume without
degradation and partition: DF
=
2.5
-
Attenuation including dilution, partition and degradation in the soil was deter-
mined as the product DF dilution *AF biodegradation *AF partition and was estimated in
moderately and greatly pessimistic ways by using transport and fate models.
Evaluation of Case study 2
-
Tier 1
Taking only dispersion into consideration, the 2.5-fold dilution along the plume
(DF p ) is not sufficient to fulfill any quality criteria, not even the highest intervention
 
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