This was presented at the 2019 Clemson Hydrogeology Symposium. Its full title is Conceptual Site Model Development and Environmental Molecular Diagnostics Use for PlumeStop(R) Liquid Activated Carbon(TM) Application at a Trichlorofluoromethane Groundwater Plume.

1. The logo and ANTEA are registration trademarks of Antea USA, Inc.
Conceptual Site Model Development and
Environmental Molecular Diagnostics Use
for PlumeStop® Liquid Activated Carbon™
Application at a Trichlorofluoromethane
Groundwater Plume
Robert R. Thompson, III, PG, RSM
Clemson Hydrogeology Symposium
Clemson, SC
April 4, 2019

2. Site Setting
Piedmont Geology & Hydrogeology–Remediation Focused on TZ
Large Dissolved VOC Plume – 1,200 ft
Mass Flux Estimated At 210 kg/year
2 Source Areas: 1. Methylene Chloride, 2. Floor Drains Inside (ongoing)
Remediation Since 1992; Antea Group Active Since 2007
50 Acre Manufacturing Facility In North Carolina Since 1960’s

3. Site Layout and Groundwater Flow Direction
Pilot Study
Area
PlumeStop® Bio
Barrier
Methylene
Chloride
Source Area
Floor
Drain
Source
Area

4. Pre-Remedial Design Investigation
Passive Soil Gas Survey Surface Resistivity Survey
A
A’
A A’

5. 5
What Geochem Data Can Tell You
Where the site is on the REDOX
ladder
What microbial populations are likely
dominating
If one or more parameter
excessive/outside the norm
Aids in the refinement of the CSM
Critical to troubleshooting poorly performing sites

6. Pilot Study
• Pilot study using DPT
• 3,600 lbs. PlumeStop®
• 330 lbs. HRC®
• Design verification
• Soil VOC data
• Groundwater data
• Soil geotechnical data
• One year monitoring, per
NCDEQ
• State-wide use of
PlumeStop® approved
• Final Design
GW Flow

7. DO & ORP – February 2019
Dissolved Oxygen – Aerobic Conditions Oxidation-Reduction Potential – Reducing Conditions

8. Results: Post-Injection Pilot Study Data
0
500
1,000
1,500
2,000
2,500
3,000
0
2
4
6
8
10
12
9/18/2014 4/6/2015 10/23/2015 5/10/2016 11/26/2016 6/14/2017 12/31/2017 7/19/2018 2/4/2019
Freon11(µg/L)
PCE,TCE,and1,4-DioxaneConcentrations
(µg/L)
Date
15 Feet Downgradient From Pilot Study
PCE (µg/L) PCE 2L Standard
TCE (µg/L) 1,4-Dioxane (µg/L)
TCE and 1,4-Dioxane 2L Standard PlumeStop Pilot Study
Freon 11 (µg/L) Phase I PlumeStop Injection
Freon 11 2L Standard

9. Results: Post-Injection Pilot Study Data
0
100
200
300
400
500
600
700
800
900
1000
0
20
40
60
80
100
120
140
160
180
200
9/18/2014 4/6/2015 10/23/2015 5/10/2016 11/26/2016 6/14/2017 12/31/2017 7/19/2018 2/4/2019
Freon11and1,4-Dioxane(µg/L)
PCEandTCEConcentrations(µg/L)
Date
PCE (µg/L) PCE 2L Standard
TCE (µg/L) TCE and 1,4-Dioxane 2L Standard
PlumeStop Pilot Study 1,4-Dioxane (µg/L)
Freon 11 (µg/L) Freon 11 2L Standard
Phase I PlumeStop Injection
100 Feet Downgradient From Pilot Study

10. QuantArray-Chlor
MW-12S
December
2014
(pre-pilot study)
MW-12S
September
2018
Aerobic
(co)metabolic
species

11. Dehalobacter spp.
Dehalobacter spp. in Cross-Section
GW Flow Direction

12. Microbial Community Cross-Section
GW Flow Direction
GW Flow Direction

13. Total Eubacteria – Phase 2 Area
GW Flow Direction

14. Full Scale Phase 1 PlumeStop®
• Largest PlumeStop® application
for Freon 11 plume in the world
• 32,400 lbs. PlumeStop® applied
into injection wells
• 5,700 lbs. PlumeStop® applied by
DPT
• 5,400 lbs. HRC-X®
• 5,400 lbs. HRC Primer®
• 33 injection well locations
• 10 DPT locations

15. The Chemistry - Tools

16. Total VOCs October 2012
Total VOCs November 2018 Total VOCs February 2019
Total VOCs November 2014

17. Results – Post Injection Barrier Area
0
500
1,000
1,500
2,000
2,500
3,000
3,500
0
5
10
15
20
25
30
35
10/13/2013 4/11/2014 10/8/2014 4/6/2015 10/3/2015 3/31/2016 9/27/2016 3/26/2017 9/22/2017 3/21/2018 9/17/2018 3/16/2019
Freon11andTotalVOCs(µg/L)
PCE,TCE,1,4-DioxaneConcentrations(µg/L)
Date
Upgradient -- Downgradient
MW-24S PCE (ug/L) MW-24S TCE (ug/L)
PlumeStop Pilot Study MW-24S 1,4-Dioxane (ug/L)
MW-19S PCE MW-19S TCE
MW-19S 1,4-Dioxane MW-24S Freon 11 (ug/L)
Phase I PlumeStop Injection MW-24S Total VOCs (µg/L)
MW-19S Freon 11 MW-19S Total VOCs
Upgradient
Downgradient

18. Groundwater Plume Visualization-Freon 11

19. 3D Cross Sections
Total VOCs - 2014
Freon 11 - 2019
GW Flow Direction
GW Flow Direction

20. Freon 11 Cross Section – February 2019
GW Flow Direction

21. Summary
Robust data collection
is needed
Data collection during
RI pays off in the long
run
Consider all the tools
available for use
Performance
monitoring is key
Field awareness keeps
everyone safe
Preparedness
improves project
quality
Remedial design leads
to surgical placement
Consider options that
yield results and save
funds

22. Thank You
Jack Sheldon
Senior Professional, Antea Group
Jack.Sheldon@anteagroup.com
515.971.8329
If you don’t have time to do it right the first time, what makes you think
you’ll have time (and resources) to do it right the second time?
Robert R. Thompson, III, PG, RSM
Senior Professional, Antea Group
Rob.Thompson@anteagroup.com
704.324.7046
We do more than effectively
solve client challenges; we
deliver sustainable results for a
better future.