Embed Size (px)
Citation preview
OCTOBER 26-28, 2020
Colloidal Activated Carbon used to Reduce PFAS and Chlorinated Solvent Concentrations
Ryan E. Moore, CHMM
REGENESIS, Sr. Technical Manager/PFAS Program Manager
OCTOBER 26-28, 2020
• Multiple PFAS point sources
• Comingled with PCE plume
• Identified at the property boundary and migrating off-site
• Many potential downgradient receptors
• Limited budget for field testing of remedial technologies
• Question:
Can CAC be used to mitigate the risk of PFAS to the sensitive receptors?
Problem Statement
OCTOBER 26-28, 2020
Grayling Army Airfield
Grayling, MI
OCTOBER 26-28, 2020
Site Description
• Founded 1913
• 147,000 acres
• Largest National Guard training center in the country
• Training facility for military, emergency responders, and private-sector from all over the world
• Home to the Grayling Army Airfield
Grayling Army Airfield (GAAF)
• 900-acre
• Built during World War II
Site Location:Camp Grayling Joint Maneuver Training Center
OCTOBER 26-28, 2020
Former Bulk Fuel Storage Area
GAAF
N
Aquifer:• Sand & Gravel with some clay
layers• ~250’/yr gw seepage velocity• Treatment Interval 15-27’bgs
Contaminant levels:• 10 µg/L PCE• 130 ng/L Total PFAS ( PFOS,
PFHxS)
Sensitive Receptors:• Residential areas• Surface water bodies• Property Boundary
OCTOBER 26-28, 2020
Former Bulk Fuel Storage Area
*1994 Photo
OCTOBER 26-28, 2020
Remediation History
Diesel fuel release, GW extraction, GAC, and
reinjection/infiltration for diesel fuel replaced by
1984
1988
GW extraction /ex situ bio-film treatment system to
improve diesel fuel remediation, not effective on newly discovered volatiles,
replaced by
GW extraction, GAC treatment for PCE
1992
1999
Air Sparge/ Soil Vapor Extraction system installed to address identified PCE source
areas
AS/SVE system expanded and operated continually until
2002
2001
2004
Recovery well network and GAC system expanded
GAC replaced by air stripper, which is still active
2006
2016
PFAS first discovered in monitoring wells; Precise dates
and locations are not known, but suspected from AFFF
VAP conducted at boundary fence identified PFAS at
property boundary
2017
2018
CAC Field Test Initiated in the Former Bulk Fuels
Storage Area
OCTOBER 26-28, 2020
Colloidal Activated Carbon
• Size: 1 – 2 µm• 2-3 OOM smaller than GAC (500-1,000 µm)
• Size of a red blood cell
• Suspended in water/polymer
• Distributes widely at low pressure
• Huge surface area that allows for extremely fast sorption
• Converts polluted aquifer into purifying filter
OCTOBER 26-28, 2020
Why Colloidal Activated Carbon?
• Limited destructive options
• Low Cost• No O&M costs or generated waste• Reapplication only after years/decades
• Localized containment/concentration of PFAS• Pair with future destructive technologies?
• In Situ Sequestration • Preventing contaminant migration • Removes exposure → removes the immediate
risk
OCTOBER 26-28, 2020
Treatment of Flux Zones and Control of Back Diffusion
OCTOBER 26-28, 2020
CAC: Modes of Action
• Mode of Action with PFAS:• Dynamic adsorption
• Not a permanent immobilization
• Effect: Increases the retardation of a PFAS plume• Groundwater retardation factor of 1
• Natural retardation factors for PFAS: 3-20
• Retardation factors achievable with CAC: 10,000• Containment for decades
• PlumeForce Modeling™
• Third Party Modeling (scientific articles available)
OCTOBER 26-28, 2020
Longevity-Third Party Review
• University of Waterloo, Waterloo, Ontario, Canada
• University of Toronto, Toronto, Ontario, Canada
• Porewater Solutions, Ottawa, Ontario Canada
• In Situ Remediation Services Ltd., St. George, Ontario, Canada
Longevity-Conclusions:• Increased by CAC concentration injected
• Length of treatment area
OCTOBER 26-28, 2020
Simple Plume Cut-Off Barrier
OCTOBER 26-28, 2020
Modeling in the Design Process
Considerations• Soil Type/Porosity
• Groundwater Seepage Velocity/Mass Flux
• Vertical Variations
• Barrier Thickness
• Carbon Demand
• Time
PlumeForce™• Long-Term Prediction Model
• Competitive Sorption and Degradation (if applicable)
• Compound Specific Isotherms
• VOCs, PFAS, etc.
OCTOBER 26-28, 2020
Modeling in the Design Process
Inputs• GW 219 feet/year
• Infinite Source
• PFOS 110 ng/L
• PFOA 8 ng/L
• PFHxA -HpA – HxS 112 ng/L
• Other PFAS 9 ng/L
• PCE 10 ug/L
• No degradation of any PFAS compound or CVOC’s
• Time (>75yrs)
Groundwater Flow
CAC
OCTOBER 26-28, 2020
Field Test Layout
2
1
3
4 5
6
7
8
9
GW Flow
5.8’
MW-29a (15’-20’) MW-29b (21’-26’)
MW-29e (15’-20’)MW-29d (21’-26’)
MW-29 (15’-20’)
MW-29c (21’-26’)
Existing monitoring well
New monitoring well
Direct-push injection location
10’
10’
6’
42’
OCTOBER 26-28, 2020
Field Test Layout
OCTOBER 26-28, 2020
Field Test Layout
2
1
3
4 5
6
7
8
9
GW Flow
sb9-4
sb1-2.5
5.8’
sb7-2.5
sb8-2.5
sb9-2.5
sb2-2.5
sb5-2.5
MW-29a (15’-20’) MW-29b (21’-26’)
MW-29e (15’-20’)MW-29d (21’-26’)
MW-29 (15’-20’)
MW-29c (21’-26’)
Existing monitoring well
New monitoring well
Direct-push injection location
Direct-push searcher core
10’
10’
6’
42’
OCTOBER 26-28, 2020
CAC-Distribution Confirmation
30 feet bgs
15 feet bgs
27 feet bgs
0 feet bgs
OCTOBER 26-28, 2020
Soil Vial Shake Test
CAC-Distribution Confirmation
OCTOBER 26-28, 2020
CAC-Distribution Confirmation
30 feet bgs
15 feet bgs
27 feet bgs
0 feet bgs
OCTOBER 26-28, 2020
Soil Vial Shake Test
CAC-Distribution Confirmation
OCTOBER 26-28, 2020
Field Test KitSample MW-29c
CAC-Distribution Confirmation
OCTOBER 26-28, 2020
Field Test Layout
2
1
3
4 5
6
7
8
9
GW Flow
sb9-4
sb1-2.5
5.8’
sb7-2.5
sb8-2.5
sb9-2.5
sb2-2.5
sb5-2.5
MW-29a (15’-20’) MW-29b (21’-26’)
MW-29e (15’-20’)MW-29d (21’-26’)
MW-29 (15’-20’)
MW-29c (21’-26’)
Existing monitoring well
New monitoring well
Direct-push injection location
Direct-push searcher core
CAC present in searcher core
10’
10’
6’
42’
OCTOBER 26-28, 2020
CAC-Distribution Confirmation
OCTOBER 26-28, 2020
OCTOBER 26-28, 2020
OCTOBER 26-28, 2020
2
1
3
4 5
6
7
8
9
sb9-4
sb1-2.5
5.8’
sb7-2.5
sb8-2.5
sb9-2.5
sb2-2.5
sb5-2.5
MW-29a (15’-20’) MW-29b (21’-26’)
MW-29e (15’-20’)MW-29d (21’-26’)
MW-29 (15’-20’)
MW-29c (21’-26’)
Existing monitoring well
New monitoring well
Direct-push injection location
Direct-push searcher core
CAC present in searcher core
10’
10’
6’
42’
Wells for water-level monitoring
to evaluate true flow-paths
New nested downgradient monitors
MW-29M
(15’-20’)
MW-29K
(15’-20’)
MW-29N
(15’-20’)
26’
45’
MW-29f (21’-26’)MW-29G (15’-20’)
MW-29h (21’-26’)
MW-29j (15’-20’)
GW Flow
OCTOBER 26-28, 2020
OCTOBER 26-28, 2020
OCTOBER 26-28, 2020
OCTOBER 26-28, 2020
Summary
• Very Successful Test• Verified distribution of CAC
• Sustained reductions of PFAS and PCE over time
• Anticipated to last for decades
• Low cost alternative for possible remediation
• ANSWER: Yes, CAC can be used to eliminated risk to potential multiple receptors!
OCTOBER 26-28, 2020
PFAS Research Articles
• In-Situ treatment of PFAS-impacted groundwater using colloidal activated carbon
• http://www2.regenesis.com/pfas-wiley-article
• Evaluating the longevity of a PFAS in situ colloidal activated carbon remedy
• http://www2.regenesis.com/grant-carey-wiley-remediation-journal
OCTOBER 26-28, 2020
Thank you
Patricia Byrnes LymanInvestigation/Remediation ManagerEnvironmental Section, JFHQMichigan Army National [email protected]
OCTOBER 26-28, 2020
Thank you!QUESTIONS?
• Ryan Moore, CHMM
• Sr. Technical Manager/PFAS Program Manager
