Environmental Engineering Reference
In-Depth Information
TABLE 11.2
Site Breakdown by Contaminant Type and Cost
Total Number
of Sites
Number of
Groundwater Sites
Number of Free
Product Sites
Cost (Million
Dollars)
Contaminant
PAHs
76
8
6
6.4
LNAPL VOCs
72
33
15
253.9
DNAPL VOCs
67
37
0
215.9
Lead
25
0
0
7.4
PCBs
14
0
0
14.6
Chromium VI
12
6
0
57.2
Mercury
7
0
0
10.8
Perchlorate
3
2
0
1.1
Arsenic
2
1
0
4.8
Chlordane
2
0
0
0.2
Total
280
87
21
572.3
TABLE 11.3
Breakdown of Soil Remediation
Number
of Sites
Frequency
Selected (%)
Soil Remediation Technology
Excavation
259
93.5
Risk assessment
85
32.8
Institutional controls
70
25.1
SVE
49
17.6
Capping
48
17.2
Thermal treatment
5
1.8
In situ chemical treatment
5
1.8
TABLE 11.4
Breakdown of Groundwater Remediation
Number
of Sites
Frequency
Selected (%)
Soil Remediation Technology
Risk assessment
73
84.1
Institutional controls
63
72.4
In situ chemical treatment
41
47.1
Pump and treat
35
40.2
MNA or NA
31
35.6
Air sparging
8
9.2
Thermal treatment
2
2.4
soil or contaminated soil with excavation impediments. The multiple use of remedial tech-
nologies was also selected when groundwater was impacted, especially with Chromium
VI or DNAPL. As shown in Table 11.4, groundwater pump and treat is not currently a pre-
ferred remedial method. The exception here occurs when there is free product or an incom-
patible overlapping multicompound contaminant plume (e.g., heavy metals and DNAPL).
In situ chemical treatment is currently the preferred remedial method for chromium VI and
DNAPL contaminated groundwater (e.g., calcium polysulfide, ferrous sulfate).
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