A modern approach to Site
Investigation and monitoring
Using the conceptual site model
and modern technologies
Leen Rubberecht (MWH Mechelen)
Robert-jan Stuut (MWH Arnhem)
Contents
ƒ Traditional Approach
ƒ What about innovative / new
technologies
ƒ Are these techniques really
innovative??
ƒ EPA-TRIAD approach
Traditional Approach
High uncertainty in results!
70 tot 90 % due to heterogeneity of soil matrix,
only 10 to 30% due to analytical process!!!
“new” technologies
ƒ Determine lithology (CPT, GPR, HRS)
ƒ (on-site) screening techniques (MIP,
ROST, XRF)
ƒ Sampling techniques (hydrasleeve,
sorbicell, ...)
4
Why should we also use
innovative / new technologies?
ƒ Better understanding of lithology (and relation with
contaminants)
ƒ Minimize sampling influences
ƒ Efficient sampling and monitoring
ƒ Representative measurements
ƒ Define preferential pathways
ƒ Minimize failure costs
Determine Lithology : But WHY?
THE PROBLEM IS HETEROGENITY?
Soils are heterogeneous
Samples are a small subset
Can’t sample everything!
Determine lithology
ƒ Drilling
ƒ Cone Penetrometer Technology
ƒ Geophysical Techniques
7
Sampling techniques : minimize
sampling influences
Sampling techniques : efficient
sampling and monitoring
Diffusion sampler
Sorbicell
On-site screening :
representative measurements
Vertical Scale 1:200
MIP 24
Monitoring Well 41
PCE < 0,1 µg/l
TCE < 0,1 µg/l
DCE 37.250 µg/l
VC 14.000 µg/l
10
20
30
40
50
60
70
0
2
4
6
8
10
0,0
DELCD [V]
0,1
0,2
PID [V]
0,3
0,4 0,0
0,1
0,2
FID [V]
0,3
0,4 0,00
0,05
0,10
0,15
0,20
0
1
0
1
2
2
3
3
4
4
5
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41
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43
Depth in m bgs.
Depth in m bgs.
Cone Resistance in MPa Friction Ratio in % [Conductivity mS/m*5)
0
Filter 3.2
PCE < 0,1 µg/l
TCE < 0,1 µg/l
DCE < 0,1 µg/l
VC < 0,1 µg/l
Filter 3.3
PCE < 0,1 µg/l
TCE 0,11 µg/l
DCE 4,6 µg/l
VC
54 µg/l
Filter 3.4
PCE < 0,1 µg/l
TCE < 0,1 µg/l
DCE 12 µg/l
VC
2,2 µg/l
4
3
2
1
0
MIP2
30
29
28
27
26
25
24
23
22
21
20
19
Dynamic GW-Table Depth [m bgs.]
41
40
39
38
37
36
35
34
33
32
31
6
5
1
0
0,0
6
5
4
3
2
Friction ratio [%]
1,0
0,5
7
1,5
6
5
4
3
2
1
0
18
17
16
15
14
13
12
11
10
9
8
7
30
29
28
27
26
25
24
23
22
21
20
19
DELCD [V]
41
40
39
38
37
36
35
34
33
32
31
On-site screening : define preferential pathways
m u. GOK (0,00 m NN)
-1
-2
-3
-4
-5
6
5
4
3
2
1
0
10
9
8
7
18
17
16
15
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12
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m
-6
MIP2
Dynamic GW-Table Depth [m bgs.]
-6
-5
-4
-3
-2
-1
0
1
DELCD [V]
Friction ratio [%]
2
3
4
5
6
0
1
2
3
4
5
6
7
0,0
0,5
1,0
0
1
2
3
4
5
6
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41
Höhenmaßstab: 1:250
1,5
0
1
2
3
4
5
6
7
8
9
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39
40
41
Blatt 1 von 1
Minimize failure costs 1
Traditional SI, > 5 years, pilot
remediation
38 MIP (50 m) + 33 Bat-samples, determine
preferential pathway in 6 weeks
Minimize failure costs 2
Groundwater Extraction Well
ur
DELCD
PID
[V]
[V]
FID
[V]
Teufe [m u. GOK]
50 mg/l TCE- 5 years Pump and Treat
led to 4 mg/l TCE
0
1
2
3
4
5
0
1
2
3
4
5 0,0
0,3
0,6
0,9
1,2
1,5
0
1
2
3
4
5
MIP 39
6
7
92 mg/l TCE
8
9
10
11
12
13
14
MIP 56
156 mg/l TCE
15
“Oops - I’m the
Source Area”
ur
DELCD
PID
[V]
[V]
FID
[V]
Teufe [m u. GOK]
0
1
2
3
4
5
0
1
2
3
4
5 0,0
0,3
0,6
0,9
1,2
1,5
0
1
2
3
MIP 61
4
5
TCE-NAPL
6
7
8
9
10
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The TRIAD approach
ƒ What is TRIAD?
ƒ How do I use TRIAD?
ƒ Modern tools for chlorinated sites.
ƒ What problems are there?
ƒ What are the benefits?
WHAT IS TRIAD?
Site specific systematic
planning
Real Time Sampling
and
Analytical Techniques
Adaptive Ground
Investigation / Dynamic
Work Strategies
Front end planning
Field based assessment
Good field data management
Decision making by field staff
How do I use the TRIAD
approach?
ƒ What is the point of the
work?
ƒ What shall I use the results
for?
ƒ How shall I change my
plans?
ƒ What level/detail of
information do I need?
ƒ How fast do I want the
results?
ƒ What’s my site set-up?
ƒ What’s the most
appropriate field test
method?
Modern tools for chlorinated sites
ƒ Soilgas sampling
- Active
- Passive
ƒ In-situ screening (MIP-CPT,
Enissa-MIP, Geoprobe-MIP)
ƒ In-situ soil and groundwater
sampling (Geoprobe and
CPT-equipment)
ƒ Passive
groundwatersampling
(Sorbicell, hydrasleeve, ect)
WHAT PROBLEMS ARE THERE?
Advantages of innovative / new technologies?
ƒ Many data points at lower cost per point
More complete site characterisation
ƒ Project uncertainty
remediation success rate
Bat sampler
Source: Environmental Resources Management
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Questions? Remarks?
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