Multi-Site Performance Review of Colloidal
Carbon for Groundwater Treatment
Chad Northington, PE – REGENESIS Southeast District Manager
Overview
• Technology Development, Modes of Action & Applications
• Multi-Site Performance Review
• PFAS Containment
• Addressing Back Diffusion
Physical Differences Between PAC vs LAC
Carbon Type Particle Size (micrometers)
Granular Activated Carbon 400-1000
Powdered Activated Carbon 50-250
Micron-Scale Activated Carbon 1-2
*Pore throat diameters of typical aquifer materials range (Nelson, 2009):
Grain Size Pore Throat Diameter (micrometers)
Medium Sand 8-50
Fine Sand 5-20Silt 3-8
PlumeStop Powdered Activated Carbon
The Reagent – what it is
• A highly dispersive, injectable sorbent and microbial growth matrix
• Colloidal activated carbon (1 – 2 µm)• Size of a bacterium – suspends as ‘liquid’
• Huge surface area – extremely fast sorption
• Proprietary anti-clumping / distribution supporting surface treatment (patent applied for)
• Core innovation
• Enables wide-area, low-pressure distribution through the soil matrix without clogging
PlumeStop Mode of Action
Contaminant sorbs to sites available on PlumeStop
particle
Microbes biodegrade
sorbed contaminants
Sorption sites become available
for additional contaminant
©2015 All Rights Reserved. REGENESIS and REGENESIS product(s) are registered trademarks of REGENESIS Remediation Products.
– CVOCs including ethenes
and ethanes
– Petroleum Hydrocarbons
(TPH, BTEX, etc.)
– MTBE
– Pesticides
– PFAS
What it Treats
©2015 All Rights Reserved. REGENESIS and REGENESIS product(s) are registered trademarks of REGENESIS Remediation Products.
• Aerobic Treatment
• Electron Acceptor Addition, Sparging…
• Anaerobic Treatment
• Slow release electron donors
• Lactate, recirculation systems
• Enhanced Monitored Natural Attenuation
• Containment (PFAS)
Colloidal Carbon – A Technology Platform
©2015 All Rights Reserved. REGENESIS and REGENESIS product(s) are registered trademarks of REGENESIS Remediation Products.
+
+
1. When time is critical
2. As a long-term barrier
3. To achieve stringent cleanup standards
4. To address matrix back diffusion
5. When remediation is “flat lining”
When/Where to Use
©2015 All Rights Reserved. REGENESIS and REGENESIS product(s) are registered trademarks of REGENESIS Remediation Products.
- performance analytics -
chlorinated ethanes (TCA, DCA, CA etc.)
chlorinated ethenes (PCE, TCE, DCE, VC etc.)
Freon-11® (CFC)
MTBE
BTEX
TPH
PAHsChlorobenzene (MCB)
• >95% reduction within 90 days - 65% (typically to < MDL)
• >90% reduction within 90 days - 70%
• >80% reduction within 90 days - 90%
• <65% reduction within 90 days - 10%
Stability to date?
Data Set: Long term is up to 738 daysAverage is 199 days
70% show no change or drop further85% remain within 10% of initial result
The remainder (bar one) were pilot tests
Data Set: Long term is up to 738 daysAverage is 199 days
In Situ Containment of PFAS
17
Per- and Polyfluorinated Alkyl Substances: PFAS
• Complex mixture of fluorinated compounds– PFOS & PFOA (C8 species)
• Have been used in many consumer products, fire fighting foams
• Probable links to human health issues
Sensitive Receptors at Risk• Bodies of water
• Drinking water supplies
• Neighborhoods
• Property Boundaries
Can we protect these areas with
an in situ barrier?
Dose Response: Isotherms
©2015 All Rights Reserved. REGENESIS and REGENESIS product(s) are registered trademarks of REGENESIS Remediation Products.
PlumeStop & Shorter Chain PFAS Compounds
1
10
100
1,000
10,000
100,000
Control PlumeStop Treated
PFA
S (n
g/L)
PFAS Treatment by PlumeStop
PFOS
PFOA
PFHpA
PFBS
EPA Health AdvisoryLimit
Batch sorption test• PFOA (C8 chain)
• PFOS (C8 chain)
• PFHpA (C6 chain)
• PFBS (C4 chain)
Relative sorption: • PFOS > PFOA > PFHpA > PFBS
• PFBS will breakthrough first– PFBS was removed from
96,000 ng/L to 190 ng/L
– 99.8% sorption
Engineering the Retardation factor
Groundwater velocity
The Retardation Factor (Rf) determines how fast a contaminant moves relative to the groundwater.
Rf = 10
Rf = 2
Contaminant velocityRf = 1
aGuelfo and Higgins, 2013. Environ. Sci. Technol.
Natural Rf:
PFOA = 3a
PFOS = 19a
Rf with PlumeStop for PFOA and PFOS:
500 – 5,000
PlumeStop® Integration with Fate & Transport Models
Incorporate PlumeStop isotherm
parameters into models
Predict longevity of PlumeStop dose
Optimize the dose to meet desired
longevity
0 10 20
Scale, in meters
PFOA,PFOS concentrations in ng/L.
Location: CanadaSoil: Silty sandDTW: 4 ftGW velocity: 2-3 ft/dayHistory: • Hydrocarbon spill• Former fire training area
GW Flow
Baseline Contamination:PFOS: 0.3 – 1.5 mg/LPFOA: 0.5 – 3.3 mg/L
BTEX: <0.5 – 264 mg/LTPH: <25 – 6,000 mg/L<20, <20
540,370
1340,780
1050,5703260,1450
1250,970
<20, <20
<20, <20 <20, <20
<20, <20
490,280
Case Study
Site
bo
un
da
ry
<20, <20 <20, <20
<20, <20
<20, <20 <20, <20
<20, <20
0 10 20
Scale, in meters
PFOA,PFOS concentrations in ng/L.
GW Flow
ResultsPFOS: ND (<20 ng/L)
PFOA: ND (<20 ng/L)
BTEX: ND (<0.5 mg/L)
TPH: ND (<25 mg/L)
Through 3, 6, and 15-month (May ‘17) monitoring events<20, <20
<20, <20
<20, <20 <20, <20
<20, <20
540,3701340,780
1050,5703260,1450
1250,970
490,280
Remedial Technology Used:
Case Study
• Ability to turn the subsurface into an activated carbon filter• Injectable at low pressures, wide centers, at depth• Uninterrupted groundwater flow• Engineer the retardation factor
• Passive plume control & containment• Prevent expansion of the problem• Avoid pump & treat costs and complications
PlumeStop Benefits – Management of PFAS Plumes
• Potential to couple this technology down the road with any new developments in a destructive technology
Back Diffusion Tank Study
27
Back Diffusion
• Contaminants slowly diffuse out of the low permeability zones
• Long-lasting source of low-level contamination• Several years to decades
• Current solutions require indefinite number of treatments
• PlumeStop offers a longer-term solution
Back Diffusion
Back diffusion
Simulated Back-Diffusion Tank Study
Collaboration with: • Kevin Saller, CDM Smith• Tom Sale, Colorado State University
Investigators in a SERDP funded project: “Treatment of Contaminants in Low Permeability Zones”• Used this tank set-up to simulate back diffusion and
evaluate different remediation treatments (SERDP
Project ER-1740)
Our study goal: • Compare the performance of a PlumeStop treatment
under similar test conditions to ERD
Tank Set-up
• 0.5m x 1.0m x 2.54cm• 9 alternating high and low k zones• Low k:
– Silt from F.E. Warren AFB, WY (not sterile)
– Conductivity = 1 x 10-4 cm/sec– Foc = 0.3%
• High k: – 80% med. Sand, 20% sandy loam– Conductivity ~1 x 10-2 cm/sec
• Tank flow: bottom to top– ~0.33 PV/day
31
CLE
AN
WAT
ER(B
ack
dif
fusi
on
)
Experimental Design
1. “TCE Spill”
a. TCE saturated water flowed through tanks (~12 PV)
2. Back diffusion:
a. Influent switched to clean water until effluent TCE <5 mg/L
3. Inject remediation treatments
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
TCE
(mg
/L)
Timeline TCE
SATU
RAT
ED T
CE
Am
en
dm
en
ts
Am
en
dm
en
ts
Am
en
dm
en
ts
0 30 60 90Pore Volumes
Treatments
Tank 1 Control, no treatment
Tank 2 PlumeStop only
Tank 3 ERD Treatment➢ Lactate + DHC
Tank 4 PlumeStop + ERD➢ PlumeStop, lactate, DHC
0
2
4
6
8
10
12
14
30 50 70 90
Co
nce
ntr
atio
n (m
M)
Pore Volumes
0
2
4
6
8
10
12
14
30 50 70 90
Co
nce
ntr
atio
n (m
M)
Pore volumes
Tank Study: Effluent Results4: PlumeStop + ERD Treatment3: ERD Treatment
= Lactate/DHC applications = PlumeStop application
qPCR Data: Water
1.0E-01
1.0E+00
1.0E+01
1.0E+02
1.0E+03
1.0E+04
1.0E+05
DHC BVC TCE VCR
cells
/mL
Enhanced DHC + functional gene populations measured in PlumeStop + ERD tank.
Control
PlumeStop
ERD
PlumeStop + ERD
Reporting Limit
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
1.0E+08
High k zone Low k zone
cells
/g
4: PlumeStop + ERD Treatment
qPCR Data: Soil
Reporting Limit
Over 2 orders of magnitude DHC population increases in presence of PlumeStop
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
1.0E+08
High k zone Low k zone
cells
/g
3: ERD Treatment DHC
BVC
TCE
VCR
FLO
WPermanganate Treatment1 PlumeStop Treatment
PlumeStop Transport – Comparison to Permanganate
Hi k Low k
5 cm
Hi k Low k
1 K. Saller, T. Sale. 2013. Treating Low k Zones in Management of Contaminants Stored In Low Permeability Zones, SERDP Project ER-1740.
Demonstrated:
• Ability to distribute into the low k soils
• PlumeStop showed improved containment of back diffusing contaminants over ERD treatments alone
• Minimal daughter products observed with PlumeStop
• Orders of magnitude increase in Dehalococcoides + functional genes in the presence of PlumeStop
Simulated Back Diffusion Tank Study Recap
This presentation is the property of REGENESIS Remediation Products and its owner. You may not publish, transmit, reuse or re-post the content of this presentation for public or commercial purposes, including, without limitation, text, images and related content made available to you without the expressed permission of REGENESIS Remediation Products.
Chad Northington, PE - Southeast District [email protected]
864-884-4346
Multi-Site Performance Review of Colloidal Carbon for Groundwater Treatment
Design Verification Testing
40
Organization and Position of COC Storage Units and Transport Units
• Fine grained units - storage
• Coarse grained units – transport
Vertical and Lateral relationships between fine- and
coarse-grained units
We care about sand; how much and where is it located
REMEDIATION PRACTITIONERS NEED TO KNOW….
Mass Storage and Distribution
– Plume architecture is an expression of the organization of fine- and coarse- grained units
COC distribution is controlled by soil type positional relationships
– Determination of vertical and lateral relationships between low and high Kh zones are critical
– Remediation is target zone-specific prescription
• Most sites have several target zones based on mass, constituents, hydrogeology, etc.
SEDIMENTARY PROCESSES CONTROL RELATIONSHIPS BETWEEN FINE- AND COARSE- GRAINED UNITS
DESIGN VERIFICATION TESTING (DVT) – WHAT?
• What is DVT?– Pre-application process of data collection and analysis to verify design
assumptions of a site’s chemical and geological conditions and the viability of in situ injection(s).
– Localized, high-density identification of COC transport zones
– It is NOT just additional site assessment, different objectives
• Objective: Maximize reagent-contaminant contact– Field-verification of remedial design parameters & delivery rates
– Identification of contaminant transport strata and distribution
– Ensure accurate, efficient placement of reagents for maximum flux-interception and performance
Assists Designer in:
• Reagent Selection and Overall Approach
– Will the Original Approach Meet Objectives
• Calibrating the reagent
– COC Mass vs Reactivity
• Calibrate TTZ’s accommodation rates and volumes
– ID Hydraulic Limitations
– Can we fit the reagent in the TTZ?
• Identification of “Technical Blind Spots”
– Refines design assumptions
DESIGN VERIFICATION PROCESS - PURPOSE
DVT Elements
Soil Physical
Properties
Soil Borings-Physical Soil Description
$$Identification of physical soil properties and geology types.
Soil Settling Tube Test
$Field test to determine sand, silt and clay content.
Grain Size Analysis
$Lab analysis of soil sample particle sizes. Can be used to accurately determine soil type.
Geophysical Borehole Logging
$$$The use of Gamma-Ray, Conductivity, Resistivity and other logs for identifying the bedrock type
CPT $$$Uses a DPT rig for cone penetrometer testing for identifying soil properties and soil type
Soil & GW Chemistry
Soil Sample for COCs (TPH, VOCs)
$Samples to determine residual contaminant sorbed mass.
Fraction Organic Carbon (foc)-Soil
$ Natural organic carbon level.
List of Groundwater Parameters*
$$
Lab tests for dissolved metals and other parameters that can affect PlumeStop distribution and performance.
Installation of Additional Monitoring Wells
$$Wells to target specific intervals of GW plume.
Injection Rates &
Distribution Testing
Grain Size Analysis
$Lab analysis of soil sample particle sizes.
Hydraulic Conductivity/Pump Test
$$Field test conducted by the consultant. Significant factor in contaminant migration rates.
Clear Water Injection
Test$$
Field test conducted by RRS or Tech Services to verify injection rates, pressures and distribution
Tracer Injection
$$Field test conducted by Tech Services to verify distribution
Field Calibration
Test$
Injection testing immediately prior to full scale injection
Pilot Test $$$An injection test with Regenesis products weeks or months before the full scale application.
Transport Zones & COC Flux
Soil Borings $$Physical identification of transport zones and back diffusion zones.
Soil Settling Tube Test
$Field test to determine sand, silt and clay content.
Passive Diffusion
Bags$$
Identify transport zones contaminant concentrations.
Geophysical Logging
$$$The use of Gamma-Ray, Conductivity, Resistivity & other logs for bedrock analysis
Passive Flux Meters
$$$Sample contaminant concentrations over time to determine rate of flux.
MIP $$$DPT with interface probe to obtain high volume qualitative measurements of COCs
DESIGN VERIFICATION: PROCESS – SOIL SETTLING TUBES
Field Technique that provides semi-quantitative data to trained field geologist
Visual Determination
- Soil particle size %
- Sand, Silt, Clay
- Sand: grain size and sorting
- Enables better evaluation of particle size
- Lessens ambiguity and corrects discrepancies
- e.g. Silty sand, silty clayey sand, etc.
- High density, 1 foot vertical spacing typical
DESIGN VERIFICATION: CLEAR WATER INJECTION TEST
• Test helps document TTZ’s capacity to accept designed injection volumes
• Assists in application decisions
– Injection wells
• Screened intervals
– DPI
• top-down vs bottom-up
• Data often differs greatly from the hydraulic conductivity volume estimates
- PERFORMANCE ANALYTICS -
DESIGN VERIFICATION: EVALUATION/ANALYSIS
Site N=30
Contaminant
– 35% Petroleum
– 61% cVOC’s
• X% 1,4-Dioxane
– 4% Comingled
General Soil Type
– 50% Fine grained (Clays & Silts)
– 50% Coarse grained (Sand & Gravel)
DVT - Regenesis PlumeStop® Strategy of Success
• What’s the outcome?
– ~80% of tests to date have found unanticipated results (technical blind spots)
– 62% of preliminary designs were modified / refined
– Most of design changes have been cost-neutral
18%
18%
21%
25%
46%
HIGHER CONTAMINANT CONCENTRATIONS
THICKER CONTAMINANT ZONE
UN-IDENTIFIED CONTAMINANT TRANSPORT ZONE
LOWER INJECTION RATES/ROI
UN-IDENTIFIED HYDROGEOLOGICAL CONDITIONS
0% 10% 20% 30% 40% 50%
DVT RESULTS → DESIGN CHANGES
38% No Changes
35% Few Changes
8% Moderate Changes
8% Significant Changes
11% Injection Canceled
This presentation is the property of REGENESIS Remediation Products and its owner. You may not publish, transmit, reuse or re-post the content of this presentation for public or commercial purposes, including, without limitation, text, images and related content made available to you without the expressed permission of REGENESIS Remediation Products.
Chad Northington, PE - Southeast District [email protected]
864-884-4346
Multi-Site Performance Review of Colloidal Carbon for Groundwater Treatment
$ $ $ $BIO THERMAL
Mechanical SystemsIn Situ Injections
ISCO
REMEDIAL LIFE CYCLE COST SPECTRUM