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Evaluating Risk of Heritage LNAPL Bodies
International Petroleum Environmental Conference
10/14/14
Evaluating Risk
Source ITRC after Huntley and Beckett 2002
What is a Heritage LNAPL Body
• One or many of the following:
– Significantly aged LNAPL body
– Inherited LNAPL site with no prior remediation
– Prior remediation but no source reduction data
What is a Heritage LNAPL Body
• One or many of the following:
– Significantly aged LNAPL body
– Inherited LNAPL site with no prior remediation
– Prior remediation but no source reduction data
Remediation History ‒ 3 Vacuum Wellpoint Systems ‒ No LNAPL Recovery Data ‒ Total Flow, but Not from Individual Pumping
Wells
Evaluating Risk
• Vapor Pathway
• Direct Contact Pathway
• LNAPL Migration Pathway
• Dissolved Phase Pathway
Evaluating Risk
• Vapor Pathway
• Direct Contact Pathway
• LNAPL Migration Pathway
• Dissolved Phase Pathway
Vapor Pathway Page 1 of 1 (1)
Stieglitz Park ITF, Whiting Refinery
Sample ID : 145A
Acquired : May 30, 2012 13:43:24
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Torkelson Geochemistry, Inc.
Weathered diesel range fuel, small concentrations of finished gasoline product
Evaluating Risk
• Vapor Pathway
• Direct Contact Pathway
• LNAPL Migration Pathway
• Dissolved Phase Pathway
Evaluating Risk
• Vapor Pathway
• Direct Contact Pathway
• LNAPL Migration Pathway
• Dissolved Phase Pathway
Direct Contact Pathway
567
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Evaluating Risk
• Vapor Pathway
• Direct Contact Pathway
• LNAPL Migration Pathway
• Dissolved Phase Pathway
Evaluating Risk
• Vapor Pathway
• Direct Contact Pathway
• LNAPL Migration Pathway
• Dissolved Phase Pathway
LNAPL Migration Pathway
• New Monitoring Wells • Geologic Classification and TPH Grab Sampling • Undisturbed Cores and Discrete Interval TPH
Subsampling
LNAPL Migration Pathway
0
2
4
6
8
10
12
14
0 0.05 0.1 0.15 0.2 0.25D
ep
th
LNAPL Saturation
Water Table
LNAPL Migration Pathway
0
2
4
6
8
10
12
14
0 0.05 0.1 0.15 0.2 0.25D
ep
th
LNAPL Saturation
Water Table
Fine to Medium(SW)
Poorly GradedSand, fine tomedium (SP)
Well GradedSand withGravel, mediumto coarse (SW)
Well GradedSand, fine tomedium, tracegravel (SW)
LNAPL Migration Pathway
0
2
4
6
8
10
12
14
0 0.05 0.1 0.15 0.2 0.25D
ep
th
LNAPL Saturation
Sn Grab
Water Table
Fine to Medium(SW)
Poorly GradedSand, fine tomedium (SP)
Well GradedSand withGravel, mediumto coarse (SW)
Well GradedSand, fine tomedium, tracegravel (SW)
LNAPL Migration Pathway
0
2
4
6
8
10
12
14
0 0.05 0.1 0.15 0.2 0.25D
ep
th
LNAPL Saturation Sn Grab
Water Table
Screen Length
Fine to Medium(SW)
Poorly GradedSand, fine tomedium (SP)
Well GradedSand withGravel, mediumto coarse (SW)
Well GradedSand, fine tomedium, tracegravel (SW)
LNAPL Migration Pathway
PFS PFS TPH O/W Pc PFS PFS TPH O/W Pc PFS PFS PFS
• Undisturbed Cores Sampled for Pore Fluid Saturation Data and Capillary Pressure – Saturation Curves
LNAPL Migration Pathway
0
2
4
6
8
10
12
14
0 0.05 0.1 0.15 0.2 0.25D
ep
th
LNAPL Saturation Sn Grab
Sn Core
Water Table
Screen Length
Fine to Medium(SW)
Poorly GradedSand, fine tomedium (SP)
Well Graded Sandwith Gravel,medium to coarse(SW)
Well GradedSand, fine tomedium, tracegravel (SW)
LNAPL Migration Pathway
0
2
4
6
8
10
12
14
0 0.05 0.1 0.15 0.2 0.25D
ep
th
LNAPL Saturation Sn Grab
Sn Core
Sn API RP 40
Water Table
Screen Length
Fine to Medium(SW)
Poorly GradedSand, fine tomedium (SP)
Well GradedSand withGravel, mediumto coarse (SW)Well GradedSand, fine tomedium, tracegravel (SW)
LNAPL Migration Pathway
• Monitoring Wells with Mobile LNAPL • Tn Tests Completed (Manual Skim or Baildown)
LNAPL Migration Pathway
0
1
2
3
4
5
65.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
6/16/14 0:00 6/17/14 0:00 6/18/14 0:00 6/19/14 0:00 6/20/14 0:00 6/21/14 0:00 6/22/14 0:00 6/23/14 0:00
AN
T (f
t)
Dep
th (
ft)
Time (minutes)
Baildown Test
DTW (blue), Water Table (purple), DTP (red), ANT (green)
LNAPL Migration Pathway
LNAPL Migration Pathway
T=2 ft2/day T=1 ft2/day T=0.5 ft2/day
T=0.25 ft2/day
T=0.125 ft2/day
T=0.0625 ft2/day
T=0.03125 ft2/day
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Norm
aliz
ed D
raw
dow
n (
s/s i
nitia
l) (
ft/f
t)
Time (min)
API LNAPL Transmissivity WorkbookCalculation of LNAPL Transmissivity from Baildown Test Data
Mean LNAPL Transmissivity (ft2/d)
0.25
Standard Deviation (ft2/d)
0.08
Coefficient of Variation0.30
STEP 3: CHOOSE WELL CONDITIONS
STEP 1: RESET OUTPUT SUMMARY
STEP 4: LNAPL TRANSMISSIVITY SUMMARY
STEP 2: ENTER DATA & VIEW FIGURES
Unconfined
Confined
Perched
RESET
Output Summary
0
2
4
6
8
10
12
14
0 0.05 0.1 0.15 0.2 0.25D
ep
th
LNAPL Saturation
Sn Grab
Sn Core
Sn API RP 40
Water Table
Residual Sn
Screen Length
Fine to Medium(SW)
Poorly GradedSand, fine tomedium (SP)
Well Graded Sandwith Gravel,medium to coarse(SW)Well Graded Sand,fine to medium,trace gravel (SW)
LNAPL Migration Pathway
Evaluating Risk
• Vapor Pathway
• Direct Contact Pathway
• LNAPL Migration Pathway
• Dissolved Phase Pathway
Dissolved Phase Pathway
803A
Chemical Name Screening Level
(µg/L) 9/23/1991 9/23/2013
Benzene 5 5 U 0.50 U
Methylene Chloride 5 5.0 U
1-Methylnaphthalene 9.7 10 U 1.2 U
Bis(2-ethylhexyl) phthalate 6 28 12 U
Naphthalene 1.4 10 U 1.2 U
804
Chemical Name Screening Level
(µg/L) 10/14/1991 10/3/2013
Benzene 5 1100 0.50 U
Methylene Chloride 5 122 J 5.0 U
1-Methylnaphthalene 9.7 0.95 U
Bis(2-ethylhexyl) phthalate 6 100 U 9.5 U
Naphthalene 1.4 12 J 0.95 U
806
Chemical Name Screening Level
(µg/L) 9/24/1991 10/30/2013
Benzene 5 7 0.50 U
Methylene Chloride 5 5.0 U
1-Methylnaphthalene 9.7 13 0.96 U
Bis(2-ethylhexyl) phthalate 6 13 B 9.6 U
Naphthalene 1.4 14 0.96 U
809
Chemical Name Screening Level
(µg/L) 9/26/2013
Benzene 5 0.24 J
Methylene Chloride 5 5.0 U
1-Methylnaphthalene 9.7 5.0 U
Bis(2-ethylhexyl) phthalate 6 50 U
Naphthalene 1.4 5.0 U
• Dissolved phase sampling: September and October 2014
Dissolved Phase Pathway
• Full Dissolved Phase Plume Analysis: 2013/2014
Dissolved Phase Pathway
Next Steps
• Evaluate recent dissolved phase data
• Modeling dissolved phase contaminant transport without system pumping
• Evaluate natural attenuation using CO2 flux study, temperature profile study and evaluation of bioavailable electron acceptors
Preliminary Conclusions
• Vapor risk minimal
• Direct contact risk must be addressed by future remedy at isolated areas of high water table
• LNAPL mobility testing showed localized areas of potentially recoverable volumes but minimal risk reduction by LNAPL recovery
• Dissolved phase data suggests low risk but data gaps must be filled
Evaluating Risk
Source ITRC after Huntley and Beckett 2002
Unknown
Approaching Residual
Low Risk
Thank You
Questions
Colin McLeod colin.mcleod@urs.com
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