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 Managercnorthington@regenesis.com

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 Managercnorthington@regenesis.com

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