May 2016 - EPOC

May 2016

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Treatment of Contaminated Sites with In Situ Chemical Oxidation

Brant A. Smith P.E., Ph.D.Technical Applications Manager: ISCO

PeroxyChem

Presentation Overview

• Principles of Remediation

• Concepts of Chemical Oxidation

• Primary Chemical Oxidation Technologies

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– Catalyzed Hydrogen Peroxide (Fenton’s Reagent)

– Permanganate

– Klozur® Persulfate

• Potential Issues

• Conclusions

Principles of Remediation

• Remediation methods work to exploit a characteristic of the contamination– Vapor pressure

• Air Sparging/Soil Vapor Extraction (AS‐SVE)

– Boiling point/vapor pressure: • Thermally enhanced SVE

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• Thermally enhanced SVE

– Chemical transformations• Bioremediation• Chemical oxidation• Nucleophilic transformation• Chemical reduction• Chemical precipitation/Metals stabilization

• Remediation methods often selected based on chemical characteristics and site conditions that favor a particular method

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Reaction Pathways

• Oxidative

– Electrons are taken from contaminants CO2

• Reductive

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– Electrons are donated to the contaminants CH4

• Nucleophilic

– Substitution reaction (electron neutral)

IN SITU CHEMICAL OXIDATION: OVERVIEW

What is ISCO

• In Situ Chemical Oxidation (ISCO)– Transform/degrade contamination in

place in the subsurface

Massive supply of thermodynamically powerful electron acceptors

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• Addition of chemicals that take electrons from, or oxidizing, contaminants of concern (COCs)

• Reductive (electron donating) and nucleophilic pathways are also present with certain technologies– Allows for treatment of multiple types of contaminants

– Technology and activation method specific

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Why ISCO?

• Many in situ remediation technologies to choose from, why pick ISCO?– Cost: Often the lowest cost alternative

Time P id lt i kl ll ithi

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– Time: Provides results quickly, usually within weeks to months of an application

– Effectiveness: ISCO can treat a wide assortment of typical COCs

– Contaminant Mass: ISCO can treat a wide variety of contaminant concentrations including heavily impacted areas that may inhibit bioremediation

Compounds Degraded by ISCO

Chlorinated SolventsPCE, TCE, DCETCA, DCAVinyl chlorideCarbon tetrachloride

TPHBTEXGRODROORO

ChlorobenzenesChlorobenzeneDichlorobenzeneTrichlorobenzene

PesticidesDDTChlordaneHeptachlorLindane

Examples of Contaminants Destroyed by Klozur Persulfate (not all ISCO reagents treat all compounds listed)

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ChloroformChloroethaneChloromethaneDichloropropaneTrichloropropaneMethylene chloride

creosote

OxygenatesMTBETBA

PhenolsPhenolChlorophenolsNitrophenols

PerflourinatedFreonPFOSPFOAPFBA

ToxapheneMCPABromoxynil

PAHsAnthraceneBenzopyreneStyreneNaphthalenePyreneChryseneTrimethylbenzene

OthersCarbon disulfideAniline1,4‐Dioxane

EnergeticsTrinitrotoluene (TNT) Dinitrotoluene (DNT)RDX

Where is ISCO Applied?

• ISCO is a mass reduction technology usually used to target low mg/Kg to greater than 10,000 mg/Kg contamination– GW concentrations depend upon solubility

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• ISCO can be used to target– Source area (typical)– Plume (often depends on contaminant concentration)

• To treat both oxidized and reduced contamination

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Key to Success for Field Applications

• Reactions are known to take place on the laboratory scale

– 100% contact between ISCO and contamination

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ISCO works by establishing contact between a sufficient mass of activated oxidant with the contaminant mass in the subsurface

ISCO works by establishing contact between a sufficient mass of activated oxidant with the contaminant mass in the subsurface

Field Applications

Sufficient Mass of Oxidant

1. Target demand1. Contaminant type and mass

2. Non‐target demand

Establishing Contact

• Site Geology

• Contaminant distribution

• Reagent distribution

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3. Uncertainties and variability1. Target Demand

2. Non‐target demand

3. Contaminant distribution

• Remedial goals

• Reagent distribution

• Injection network

• Injection strategy

• Injection volume

• Contact time

• Groundwater velocity

Progression to a Field Application

Typical Path

• Path

– Bench scale tests

– Design Optimization (Pilot

Bench Scale Tests

• Evaluate potential interactions between the site geochemistry and the ISCO process chemistry

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scale tests)

– Full scale applications

– Achievement of goals or transition to another technology as part of a treatment train approach

ISCO process chemistry

• Objectives include:– Developing design

parameters

– Confirm treatment efficacy

– Satisfy regulatory concerns

• Specific tests will vary for each ISCO technology

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Design Optimization (Pilot Scale Test)

• Target Area– Typically a subset of the full

scale area – For a small area, may be the

first application in the entire area

• Critical Field Parameters– Treatment efficacy– Injection rate– Injection pressure– Distribution of reagents

• Active oxidant

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area

• Objective– Older Objective: Proof of

concept for new and emerging technologies

– Current Objective: Confirming site specific performance and design parameters

• Active oxidant• Inactive oxidant

– Potential issues

• Monitoring program– Typically more extensive than

full scale– Intended to monitor

treatment efficacy and field parameters

Full Scale Applications

Full Scale Application

• Objective

– Progress toward remedial goals

Expectations

• Is 99 percent reduction a success?

• Mass reduction– Will depend upon

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• Monitoring Program

– Monitor progress toward remedial goals

– Monitor effect of each ISCO application

• Mass reduction not always represented by groundwater concentrations

• Dosage/ability to contact contamination

• Initial concentrations

• Typically 80 to 99 percent per successful application

• Multiple applications and, potentially, multiple technologies are typically necessary for greater than 1 to 2 order of magnitude reductions

Combined Remedies/Treatment Train

• ISCO can be used as a mass reduction technology and be followed by:– Monitored natural attenuation– In situ bioremediation– In situ biogeochemical remediation

• ISCO used following:Thermal technologies

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– Thermal technologies– Surfactant/solvent enhanced extraction– Extraction systems (dual phase extraction)

• Treatment train approach works to maximize the strengths of different technologies to reflect the changing site situation– ISCO: Mass reduction (fast acting, large quantities of oxidant in injection

solution) when contact can be established– ISB/ISCR/etc: Persistence

• 6 months to 1 year following ISCO

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Monitoring Programs

• Critical aspect to ISCO design

• Objectives– Progress toward remedial goals– Assessing effectiveness of ISCO

application

• Frequency– Allow time:

• ISCO to react• Groundwater, soil and NAPL re‐

equilibrate• Can have biotic activity following ISCO

– Minimum 2‐3 months post application recommended

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• Monitoring Phase– Soil and groundwater typical– Phase monitored may be different for

each objective– Progress of ISCO best measured by

total mass reduced (GW mass plus Soil mass)

• Soil– Discrete/grab– Composite

application recommended– Multiple monitoring events

recommended

• Parameters– Contaminant– Residual oxidant– Geochemical parameters

• DO, temperature, conductivity, pH, ORP

– Others, as needed

IN SITU CHEMICAL OXIDATION:TECHNOLOGIES

MGP Site in Illinois

• Contaminant:

– ~17,000 mg/Kg TPH

– ~45,000 g/L Benzene– ~140 g/L Naphthalene

di l l

• Results:

– Less than 2,500 mg/Kg TPH

– Benzene in groundwater reduced by greater than 98 percent

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• Remedial goals:– TPH to less than 9,000 mg/Kg

– Reduce benzene in groundwater by greater than 90 percent

• Applied 46,200 lbs of AAP to site over 3 applications

– 32 g Klozur per Kg soil

percent

– State of Illinois issue a No Further Action letter

Courtesy of XDD, LLC

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Active Industrial Site

• PCE, 1,1,1‐TCA, and 1,4‐dioxane (DNAPL source)

• AAP does not produce gas during treatment

h

Contaminants

Average Contaminant Concentrations (g/L)

BaselinePost 1st

ApplicationPost 2nd

Application

Total Percent

Reduction

PCE 11,987 4,819 113 99.1

1,1,1‐TCA 8,736 5,698 64 99.3

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• Treated with two applications totaling 31,000 Kg Klozur®– 25 g Klozur per Kg soil

• Remedial goal of less than 1 mg/L for each contaminant

1,4‐Dioxane 410 1,029 165 59.8

Courtesy of XDD, LLC

Primary ISCO Oxidants

• Hydrogen Peroxide (aka Fenton’s reagent, catalyzed hydrogen peroxide)

• Permanganate

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Permanganate

• Persulfate (activated)– Alkaline

– Iron

– Heat

– Hydrogen Peroxide

Hydrogen Peroxide (Fenton’s Reagent)

• Hydrogen Peroxide is catalyzed by transition metals to form the hydroxyl radical

Fe2+ + H2O2 Fe3+ + OH. + OH‐

OH + H2O2 HO2 + OH‐ + H+

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Fe3+ + H2O2 Fe2+ + HO2 + H+

HO2 O2‐ + H+ (pKa 4.8)

Fe3+ + O2‐ Fe2+ + O2

• Forms: – Hydroxyl radical: Powerful oxidant (2.6 V) – Superoxide radical: Reductant (‐0.33 V) and nucleophile– Hydroperoxide: Nucleophile

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Hydrogen Peroxide: Key Characteristics

• Characteristics– Capable of degrading most types of contamination– Relatively inexpensive– Forms oxidants, reductants, and nucleophiles– Decomposes to water and oxygen

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• Common Issues– Sensitive to subsurface conditions (can decompose in minutes or persist for days)

• If an issue, can impede successful distribution• Stabilization agents

– Gas and heat evolution– Hydroxyl radical can be scavenged by naturally occurring carbonates

Hydrogen Peroxide: Bench Tests

• Acid buffering capacity of soils– Look for presence of carbonates (pKa 6.1)

• Stability (half life) in presence of site soils– Stabilized

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– Unstabilized– Activated

• Gas and heat evolution• Treatment efficacy• Degradation ratio

– Mass oxidant consumed per mass of contaminant degraded

Permanganate

• Sodium or potassium permanganate

KMnO4 or NaMnO4 MnO4‐

MnO4‐MnO2 (s)

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4 2 ( )

• Dark purple at >0.5 g/L and pink even at 1 mg/L• Permanganate has a redox potential of 1.7 V• Primarily used for chloroethenes (TCE and PCE)

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Permanganate Characteristics

• Characteristics and Common Issues– Direct oxidative pathway

– Reactive with:• Chlorinated ethenes (TCE, PCE, etc), some PAHs, etc

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• Little to no reaction with many other compounds (chloromethanes, chloroethanes, benzene, MTBE, etc)

– Kinetically aggressive reactions

– Field solubility:• Potassium permanganate ~30 g/L

• Sodium permanganate >400 g/L (typical application < 200 g/L)

– Very stable, can persist for months to years, if oxidant demand is met

Permanganate Reactivity

100

1000

10,000

100,000

1,000,000

f L

ife,

hr

1 Day

1 Month

1 YearMTBE 1, 4-Dioxane

Toluene

m-XyleneEthylbenzen

Benzene

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0.000001

0.00001

0.0001

0.001

0.01

0.1

1

10

1 10 100 1000 10,000 100,000

Co

nta

min

ant

Hal

f

KMnO4 Concentration at Contact Point, ppm

1 Day

1 Hour

TCE

PCE

p-Cresol

nzene

1 Min.

1 Sec.

Aldicarb

Dichlorvos2,3-Dichlorophenol

Klozur® Persulfate is:• Based on the sodium persulfate molecule

• A strong oxidant used for the destruction of contaminants in soil and groundwater

Activated Klozur® Persulfate

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• Aggressive and fast acting chemistry with extended subsurface lifetime (weeks to months) and little to no heat or gas evolution

• Applicable across a broad range of organic contaminants

•Highly soluble in water (significant oxidant mass is smaller volumes)

Field solubility of more than 500 g/L

possible

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Why Activate?

Persulfate Anion

• Relatively stable

• Kinetically slow– Persistence of weeks to

Radicals

• Kinetically aggressive

• Oxidative, reductive and nucleophilic pathways

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Persistence of weeks to months

– May not be kinetically aggressive with targeted contaminants

• Oxidative pathway – May not react with all

contaminants

p p y– Reacts with wide assortment

of common contaminants of concern:

– Oxidants more powerful than persulfate anion

Radical Formation

• Common activation methods include:– Alkaline activation

• (OH, SO4‐, O2‐)

– Nascent iron iron or iron

OxidantStandard Reduction Potential (V)

Reference

Hydroxyl radical (OH) 2.59 Siegrist et al.

Sulfate radical (SO4‐) 2.43 Siegrist et al.

Ozone 2.07 Siegrist et al.

Persulfate anion 2.01 Siegrist et al.

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Nascent iron, iron or iron chelate activation

• (SO4‐)

– Heat activation • (Temperature dependent: OH, SO4‐, O2‐)

– Hydrogen peroxide activation

• (OH, SO4‐, O2‐)

Hydrogen Peroxide 1.78 Siegrist et al.

Permanganate 1.68 Siegrist et al.

Chlorine (HOCl) 1.48 CRC (76th Ed)

Oxygen 1.23 CRC (76th Ed)

Oxygen 0.82 Eweis (1998)

Fe (III) reduction 0.77 CRC (76th Ed)

Nitrate reduction 0.36 Eweis (1998)

Sulfate reduction ‐0.22 Eweis (1998)

Superoxide (O2‐) ‐0.33 Siegrist et al.

ZVI ‐0.45 CRC (76th Ed)

Compounds Degraded by Klozur Persulfate

Chlorinated SolventsPCE, TCE, DCETCA, DCAVinyl chlorideCarbon tetrachloride

TPHBTEXGRODROORO

ChlorobenzenesChlorobenzeneDichlorobenzeneTrichlorobenzene

PesticidesDDTChlordaneHeptachlorLindane

Examples of Contaminants Destroyed by Klozur Persulfate

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ChloroformChloroethaneChloromethaneDichloropropaneTrichloropropaneMethylene chloride

creosote

OxygenatesMTBETBA

PhenolsPhenolChlorophenolsNitrophenols

PerflourinatedFreonPFOSPFOAPFBA

ToxapheneMCPABromoxynil

PAHsAnthraceneBenzopyreneStyreneNaphthalenePyreneChrysenetrimethylbenzene

OthersCarbon disulfideAniline1,4‐Dioxane

EnergeticsTrinitrotoluene (TNT) Dinitrotoluene (DNT)RDX

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Activated Persulfate

• Key Design Characteristics– Dosing persulfate in excess of contaminant and non‐target

demand– Accounting for site uncertainties (safety factor)– Radicals and reaction pathways formed depend upon activation

method

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method• Depending upon activation method, can react with most common contaminants of concern

– Highly soluble• Field > 500 g/L• Injection concentration of 200 g/L or more

– High stability in the subsurface (weeks to months) if oxidant demand is met

• Slow reaction with water

– Acid formation during decomposition• If needed, can be neutralized (alkaline activated persulfate)

Persulfate: Bench Scale Tests

• Key Bench Scale Tests:

– Base buffering capacity ‐pH > 10.5‐Alkaline activation only

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– Non target demand

– Treatment efficacy

– Degradation ratio

General Oxidant Niches• Permanganate

– Mostly chlorinated ethenes– Cost effective injection concentrations and number of applications– 10‐30 g/L potassium permanganate– High concentrations of sodium permanganate at small sites

H d id

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• Hydrogen peroxide– Most contaminants– Suitable soils (persistence/gas evolution)– 4‐10 percent stabilized hydrogen peroxide

• Activated persulfate– Applicable at most sites– Most contaminants and masses– 50‐250 g/L Klozur Persulfate– Activator pulsed or inline injected

At this time, the distribution issues due to the stability of hydrogen peroxide has severely limited its wide scale use.

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POTENTIAL ISSUES

Secondary MCLs

• Sulfate (250 mg/L)– Has not typically been an issue

– Several fate mechanisms for sulfate depending upon site geochemical conditions

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site geochemical conditions• Persistence

• Precipitation as a sulfate such as CaSO4

• Reduction and potential precipitation as metallic sulfide (FeS)

• Manganese (0.05 mg/L)– Under neutral pH, permanganate becomes solid Mn04– Under acidic conditions, reaction can result in Mn (II)

Metals Mobilization

• Metals solubility tends to follow pe‐pH diagrams

• As geochemical conditions return to baseline, metal concentrations should also return

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– Will conditions return to baseline?

• If concerned, could be evaluated in the bench or design optimization phases– If bench, may need to mimic site returning to

baseline conditions– If field, monitor long enough for geochemical

conditions to recover

• Combined remedial– Reduction technology (ISB/ISCR) could

mitigate metals mobilization, if present

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Summary

• ISCO consists of a series of technologies with decades of history of successfully remediating a wide variety of common

i f

• Common keys to success: Establishing contact of sufficient activated oxidant mass with the contamination

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contaminants of concern

• Each technology has unique characteristics that should be considered in the selection and design phases

• Bench tests can be used to determine key design parameters

ISCO Resources

• SERDP‐ESTCP (ER‐0623‐Siegrist, Crimi, and Simpkin)– Video Short Course/Workshop

– Design Tool

– Monograph: Siegrist et al (2011)“In Situ Chemical Oxidation for G d t R di ti ” SERDP ESTCP M h S i

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Groundwater Remediation” SERDP‐ESTCP Monograph Series, Springer (ISBN: 978‐1‐4419‐7825‐7)

• Huling & Pivetz (2006) “In‐Situ Chemical Oxidation‐Engineering Issue” (EPA/600/R‐06/072)

• Watts & Teel (2006) “Treatment of Contaminated Soils and Groundwater Using ISCO” J. Environ. Eng (10) 2‐9

CASE STUDY

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Background

• Located in the Chelsea neighborhood of New York City.

• Site uses included lumber yard, metal works facility auto repair

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metal works facility, auto‐repair facility, coal yard, piano manufacture, livery car service, and gasoline station.

• Leaking underground storage tanks observed at site.

Contractor: XDD, LLCConsultant: Fleming‐Lee Shue

Target Area

• Approximately 6,500 ft2

(185 ft x 35 ft).

l f

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• Treatment Interval of 9 to 14 ft bgs.

• Sandy and silty‐sandy material.

Contaminants of Concern

• Average Concentration of Petroleum Hydrocarbons:

– 3,000 g/L BTEX

– 140 g/L Naphthalene

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g/ p

– 1,400 mg/kg GRO +

DRO

• DRO and GRO up to 3,760 and4,180 mg/kg, respectively.

• Variable GRO to DRO distribution indicated possible multiple releases.

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Bench‐Scale Tests

• Evaluated catalyzed hydrogen peroxide (CHP) and alkalineactivated persulfate (AAP).

• CHP eliminated as peroxide decomposed rapidly even withstabilizing reagents, likely limiting subsurface distribution and

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stabilizing reagents, likely limiting subsurface distribution andresulting in rapid release of gas.

• Alkaline activated persulfate selected for effectiveness andchemical compatibility.– Reduced BTEX by 64‐77%.

– Reduced total TPH by 50%, with 50% percent of persulfate massremaining.

Field Application Design

• Designed based on multiple applications with emphasis onachieving remedial goals in single application.

• Injection wells installed to be accessible upon completion.

• Design called for 100,000 to 180,000 lbs of persulfate.

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– 72,700 lbs in first application

– 60,300 lbs of 50% sodium hydroxide

– Approximately 35,000 gallons of reagent solution (250 g/Lpersulfate)

• Design incorporated the RemMetrik process utilizing Wavefronttechnology.

Field Application Logistics

• Difficult spatial constraints from construction activities

• Temporarily closed lane of W. 28th St. each day for batching. R d d i ST

.

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Road was open during injection.

• Over 400 daily construction personnel

• Total access window of 9 days.

WELLFIELD

MIXING & DIST. SKID

CHEMICAL BATCHING & STORAGE

W. 28THS

May 2016

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Batching

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Mixing and Distribution Areas

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Well Field

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May 2016

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Field Application

• Occurred May 7 to 17, 2013

• Performed by XDD in cooperation with ZEBRA Environmental and Fl i L Sh

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Fleming‐Lee Shue.

• 72,372 lbs of alkaline activated Klozur persulfate injected in 35,432 gallons of solution.

• Completed on schedule and within budget, with no impact to construction activities.

Groundwater Results

• Monitoring conducted approximately 5 months after the application in three quarterly events.

• BTEX and naphthalene GW concentrations decreased

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by 92 to 95%.

Rebound was Not Observed

Soil Results

• Soil sampled approximately 5 months after the application.

• BTEX concentrations reduced by 99.9%.

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BTEX concentrations reduced by 99.9%.

DRO/GRO Soil Concentrations were

reduced by an Average of 99.2

percent

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Conclusions

• Single application of alkaline activated persulfate effectively treated BTEX, DRO and GRO

Up to 4 000 mg/Kg DRO and GRO

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– Up to 4,000 mg/Kg DRO and GRO

• No rebound observed after 3 quarterly monitoring events.

• Site closed by NY‐DEC

Questions

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Brant Smith, P.E., [email protected]

Brant Smith, P.E., [email protected]

May 2016

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In Situ Chemical Reduction (ISCR)

Fundamentals related to selection, design and distribution of ISCR technologies at contaminated sites

Ravi Srirangam P.E., Ph.D.Ravi Srirangam P.E., Ph.D.

PeroxyChem Environmental Solutions

Design and Application of Insitu Treatment Technologies

CT/MA

May 2016

BASIC PRINCIPLES OF ISCR

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The beginning of ISCR for soil and groundwater applications

“Rediscovery” of McCarty and Vogel Postulated Abiotic Pathways – “oxidation, reduction, substitution, and dehydrohalogenation reactions occur abiotically or in microbial systems”

Started with an interest in Abiotic MNA

B tler E Ha es K 2000 Kinetics of the transformation of halogenated

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Butler, E., Hayes, K., 2000. Kinetics of the transformation of halogenated aliphatic compounds by iron sulfide. Environ. Sci. Technol. 34, 422–429.

Lee, W., Batchelor, B., 2002. Abiotic reductive dechlorination of chlorinated ethylenes by iron bearing soil minerals. 1. Pyrite and magnetite. Environ. Sci. Technol. 36, 5147–5154.

Wilson, J. T. (2003). Abiotic reactions may be the most important mechanism in natural attenuation of chlorinated solvents. Presented at the AFCEE Technology Transfer Workshop, Brooks AFB, San Antonio, TX.

May 2016

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What is ISCR?

• Reduction adds electrons to the contaminant (need an electron donor)…… Oxidation removes electrons from the contaminant (need an electron acceptor)

• ISCR involves transfer of electrons to contaminants from reduced metals (ZVI, ferrous iron) or reduced minerals (magnetite, pyrite etc.)

• ISCR of CVOCs occurs via both abiotic as well as abiotic

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• ISCR of CVOCs occurs via both abiotic as well as abiotic pathways....because both processes occur simultaneously in the subsurface

• Chlorinated Solvents

PCE, TCE, cis-DCE, 1,1-DCE, VC

1,1, 2,2-TeCA, 1,1,1-TCA

CT, CF

• Pesticides

Toxaphene Chlordane Dieldrin Pentachlorophenol

Examples of Contaminants Destroyed

Contaminants Treated via ISCR

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Toxaphene, Chlordane, Dieldrin, Pentachlorophenol

• Energetics

TNT, DNT, RDX, HMX, Perchlorate

• Heavy Metals

Examples of Contaminants That Require Organic Amendment to ZVI for Destruction

• Chlorinated Solvents 1,2-DCA DCM, CM

Direct Dechlorination Reactions

Reactions:

Fe0 Fe2+ + 2e-

6

Fe0 Fe2 + 2e

2H2O 2H+ + 2OH-

2H+ + 2e- H2(g)

R-Cl + H+ + 2e- R-H + Cl-

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Role of ZVI and DVI (Fe(II)

• Significantly reduced half-lives of CVOCs in the presence of ZVI

• Requires direct contact with ZVI surface

• Reaction is abiotic reductive dehalogenation; minimizes/eliminates DCE/VC

• ZVI provides a long-term source of DVI to promote indirect chemical reduction of CVOCs (formation of reactive iron and iron sulfide minerals)

• β-elimination is the dominant pathway (~90%); ZVI generates hydrogen so some biotic reductive reactions are supported

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DCE/VCpp

Typical CVOC Half-lives (Room temperature)

0

1

2

3

PCE TCE cDCE tDCE 11DCE VC CT TCM 111TCA112TCA

Ha

lf-l

ife

(h

rs))

ISCR CONFIGURATION AND CASE STUDIES

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Common ISCR Implementation Methods

Hydraulic fracturing/injection (120 ft, 37 m)

Pneumatic

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soil mixing

(40 ft, 12 m)

pneumatic fracturing

(90 ft, 27 m)

NitrogenGas Source

Overburden

Treatment ZoneInjector

Atomized Slurry in Gas Stream

Packer

Pneumatic Injection Module

Ferox InjectionTrailer

Direct injection (30ft,9m)

continuous trenching

(35 ft, 11 m)

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Expansion of Granular Iron Grain

Size Range

• 0.25 to 2 mm (-8 to +50 US mesh) fortrenched PRBs

• 0.07 to 1.7 mm (-12 to +200 US mesh)for hydraulic fracturing

• Pneumatic/hydraulic injection(microscale, D90 of 140 micron)

• mixed into clean soil backfill following excavation of contaminated soils

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g(0.25 to 2 mm)

• physical mixing of iron and clay into the contaminated zone ( -50 mesh)

• 10 to 70 micron material in conjunction with other biological amendments-Injections

• Nanoscale materials (50-300 nm)

Commercial Facility, Mississauga, ON(February 2008)

• Former dry cleaner• Risk‐assessment to address source and on‐site contamination

• PRB to prevent off‐site migration

• Continuous trencher• Depth of 9 m• 125 m long

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First ZVI PRB Installation in the Netherlands

Start of trenching

Continuous Backfill of Iron/sand

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• Continuous trencher (CT) was used to install 120 m long PRB, with 0.3 m trench width (1.0 m to 5.5 m bgs).

• Two 30 m long HDPE wing sections were also installed using the CT.

• The PRB consisted of a granular iron and sand mix with 40% ZVI (v/v).

trenching Iron/sand

Outline of the installed Iron/sand PRB

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Netherlands PRB-February 2007 Results

0

20

40

60

80

Upgradient Downgradient

Con

cent

ratio

n (u

g/L)

Transect 1

Transect 2cDCE

0

10

20

30

40

Upgradient Downgradient

Con

cent

ratio

n (u

g/L)

Transect 1

Transect 2VC

Advantages

• 13 year operating record at oldest commercial facility

• possible benefits due to hydrogen gas, low Eh conditions (microbial activity)

• at most sites, if 5 to 8 years can pass before rejuvenation or

Long Term Performance of Commercial Systems

replacement, then technology is economically attractive

Disadvantages

• Contact -very critical

• Passivation of Iron surfaces

• Increasing implementation costs with Depth

Engineered ISCR?

Simple carbon donors

ZVIComplex carbon donors/ISRM

Engineered ISCR

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Bacterial inoculation

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Engineered Reductants

Engineered ISCR:

• Amendments that combine chemical reductants (especially ZVI) withmaterials that stimulate microbial activity (organic carbon in variousforms) are available as commercial products. The products includeEHC® and Daramend®(PeroxyChem), ABC® + (Redox Tech, LLC),

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( y ), ( , ),and emulsified zero-valent iron (EZVI) (National Aeronautics and SpaceAdministration).

• This approach relies on taking advantage of synergies offered by ZVIand organic carbon to further enhance the ISCR mechanism.

EHC® Reagent Composition

EHC is delivered as a dry powder and includes:

Micro-scale zero valent iron powder(standard ~40%)

Controlled-release, food grade, complex carbon (plant fibers) (standard ~60%)

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Major, minor, and micronutrients

Food grade organic binding agent

Sustainable Solutiono By-product ZVIo Food production by-products

Mechanisms Zone of Influence

Bacteria

VFAsN trients

Direct Chemical Reduction requires contact with ZVI particle

Extended Zone with Biological Reduction and Indirect Iron Effects

Advection and Dispersion

NutrientsFe+2 H2

Diffusion between Solid ISCR seams

H2Fe+2

Fe+2 H2

H2

VFAs

VFAs

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Hypothesized reaction Pathways

Biotic AbioticPCE

TCE

Cis 1,2‐DCE Trans 1,2‐DCE

PCE

TCE

cis1,2‐DCE

Dichloroacetylene

VC

Ethene

Ethane

VC

Ethene

Ethane

Chloroacetylene

Acetylene

Hydrogenolysisβ‐elimination

CO2 – CH4 – H2OCO2 – CH4 – H2O

Hydrogenation

DESIGN AND IMPLEMENTATION OF ENGINEERED ISCR

20

Remediation Strategy

Source Area/Hotspot Treatment

Injection PRB for Plume Control

Plume Treatment

21

May 2016

8

1. What should the strategy be based on the site-specific goals?

• Residual source area treatment / Plume treatment / PRB

2. Which product to use, how much, how frequent ?

• Make up of target contaminants

• Desired reduction in concentration of CVOCs?

• Estimated mass of CVOCs

• Prevailing geochemistry (DO ORP)

Key Design Questions?

22

• Prevailing geochemistry (DO, ORP)

• Pathways required to treat the suite of CVOCs

• Product longevity

• Product distribution under the site-specific geologic/hydrogeologic conditions (depth, geology)

• Demand from CEAs

• Site-Specific Design Factor

3. Are other additives required (buffer, bioaugmentation etc.)?

• Potassium bicarbonate / dolomite

• SDC-9 / KB-1

1. Can the required product be applied in one event or multiple events are required?

• Available pore volume v/s injected volume

2. Application Method

• DPT

Injection Wells

Key Implementation Questions

23

• Injection Wells

• Fracturing

• Soil Blending

3. ROI and number of injection points?

• ROI increases with permeability-less injection points

• ROI increases with high pressure injections

1. Distribution of Slurries (all engineered ISCR products contain ZVI)

• Top Down / Bottom Up for DPT

• Fracturing (pneumatic/hydraulic)

2. Mixing / Pump Requirements

• Good mixing to eliminate clogging

• Positive displacement pumps/ high flow rate

Key Implementation Questions

24

3. Injection Spacing (horizontal/vertical)

• It is not only about how far you can distribute the reagent

4. Verification of Distribution

• Magnetic separation

• Visual inspection of cores

May 2016

9

Methods to Validate ROI

Verification of direct product placement:

Visual observation of fractures in soil cores.

Magnetic separation of ZVI from soil cores.

Monitoring of ground deformation using uplift stakes or tilt meters (usually used during fracturing).

25

Extended zone of influence:

Groundwater Indicator Parameters (TOC, Fe, geochemical parameters)

How Far is Substrate Distributed?

26

Solid ISCR® Design Calculation Steps

1. Calculate quantity of EHC required

• Hydrogen demand from CEAs and CVOCs in the treatment area

• Multiply the hydrogen demand by specific hydrogen capacity of EHC (94 g H2/kg of EHC),

• Multiply the theoretical EHC demand by a site-specific design factor (1 to 10)

• If the calculated demand is less than the default value, use the default value

• Recommended default values are:

• 0.15 to 0.25% by wt of soil for plume treatment

• 0.25 to 1.0% by wt. for source area treatment

8 out of 10 times selected dosage is based


27

y

• 0.50 to 1.5% by wt. for a PRB

2. Assess if the quantity estimated can be injected

• If required EHC slurry volume is less than 15% of the total porosity in the treatment zone, the quantity can be injected.

• If more than 15%, multiple injection events may be required spaced 6 months apart.

• If slurry volume is less than 10%, increase the volume by diluting the slurry to inject at a minimum 10% of the PV.

gon default values

gon default values

May 2016

10

Liquid ISCR Design Calculation Steps

1. Calculate quantity of substrate required

1. Hydrogen demand from CEAs and CVOCs in the treatment area

• Multiply the hydrogen demand by amount of H2 produced per unit quantity of substrate eg: (0.141 HRC , 0.0145 –Lactate 0.322 -EHC Liquid, 0.359 -soy bean oil

• Multiply the theoretical demand by a site-specific design factor (1 to 10)

• Calculate the required concentration of TOC in pore water. If the calculatedconcentration is less than the default value, use the default value

• Recommended default values are: 8 t f 108 t f 10

28

Recommended default values are:

• 1,000-5,000 mg/L for plume treatment

• 5000-10,000 mg/L for residual source area treatment

• 10,000-15,000 mg/L for source area and PRB

2. Assess if the quantity estimated can be injected

• If required substrate volume after X dilution is greater than 15% but less than 30% of the total porosity in the treatment zone, the quantity can be injected.

• If it is more than 50%, the dilution factor can be reduced to inject a concentrated solution or perform multiple applications.

• If it is less than 15%, increase the volume by diluting the solution or increasing the application rate.


on default values


on default values

SOLID-ISCR CASE STUDIES

29

EHC® Case Study – Source Area / Grid Injection

• Site: Former Dry Cleaner, OR

• Contaminants: PCE ~ 22,000 ug/L

TCE ~ 1,700 ug/L

DCE ~ 3,100 ug/L

VC ~ 7 ug/L

30

• Treatment: 10K lbs (4.5 kg) in 5 days32 injection ptsTarget area = 825 ft2 x 20 ft deep Vertical Interval = 10 to 30 ft bgs

Low permeability lithologyLarge seasonality in GW flow

Application rate - 0.6% by wt. to soil

• Material Cost: $1.24/ft3, ~$20,000

May 2016

11

EHC® Case Study Results -Indicator Parameters

0

1

2

3

4

5

6

0 5 10 15 20 25 30 35 40C

onc.

(m

g/L)

Time post EHC injection (months)

Dissolved Oxygen

-300-250-200-150-100-50

050

100150

0 5 10 15 20 25 30 35 40

OR

P (m

V)


ORP

31

NW sampling cluster NE sampling cluster

SW sampling cluster SE sampling cluster

05

10152025303540

0 5 10 15 20 25 30 35 40

Con

c. (

mg/

L)


Sulfate

0

5

10

15

20

25

0 5 10 15 20 25 30 35 40

Con

c. (

mg/

L)


Methane

EHC®

Case Study Results

PCE

TCE0

5,000

10,000

15,000

20,000

25,000

30,000

-18 0 1 5 8 12 14 18 22 24 31 34

Con

c. (

ug/

L)

NW sampling cluster

0

1,000

2,000

3,000

4,000

5,000

6,000

-18 0 1 5 8 12 14 18 22 24 31 34

Con

c. (

ug/

L)

NE sampling cluster

32

c-DCE

VC

0

2,000

4,000

6,000

8,000

1 5 8 12 14 18 22 24 31 34

Con

c. (

ug/

L)

Time post injections (months)

SE sampling cluster

0

2,000

4,000

6,000

8,000

10,000

12,000

1 5 8 12 14 18 22 24 31 34

Con

c. (

ug/

L)

Time post injections (months)

SW sampling cluster

Time post injections (months) Time post injections (months)

Upstate NY Case Study

ISCR pilot and Full scale Injections• Manufacturing site with DCE stall historically• An ISCR (EHC) pilot test was previously

conducted in the CVOC source area in Feb 2011.

• Full scale injections were designed as multiple events spread over 2 years both in the source area and downgradient (PRB) to prevent offsite plume migration

Design parameters:• The injections were conducted around

monitoring wells MW-11, MW-17 and MW-07 in Sep 2011 and Apr 2013

• Bioaugmentation was done using SDC-09 at the end of each injection event

33

May 2016

12

EHC®

Case Study Results

34

EHC®

Case Study Results

35

• Site: Confidential Site, KS

• Contaminant: Carbon Tetrachloride

2600 ft / 800 m plume

• Treatment: 48K lbs (21.7kgs) EHC PRB

• Application PRB installed down-gradient of St t

ISCR PRB- Plume Treatment

36

Strategy: source area

Installed line of injection points 10 ft / 3 m apart

PRB extends width of plume =

270 ft / 90 m long

Installed in 12 days using direct inject

Courtesy of Malcolm Pirnie (Arcadis)

discharges into small creek

May 2016

13

44<1

<1

120067

25<1 <1

19

May 2010

60<1

<1

57062

31<1 <1

21

October 2009

70<1

<1

1400130

29<1 <1

21

April 2009

150<1

<1

620170

49<1 <1

37

October 2008

82<1

<1

1400300

57<1 <1

13

April 2008

98<1

<1

1600170

27<1 <1

14

August 2007

36<1

<1

2700620

33<1 <1

17

February 2007

47<1

<1

770140

100011 <1

140

March 2005

ISCR - PRB

37

1575

16

72<1

5.825

<1

EHC Treatment Zone

Monitoring well andCT concentration (ug/L)

N

Property Line

0 300 600

SCALE IN FEET

1635

21

120<1

1334

<1

EHC Treatment Zone


N

Property Line

0 300 600

SCALE IN FEET

2117

62

260<1

1589

<1

EHC Treatment Zone


N

Property Line

0 300 600

SCALE IN FEET

1254

110

490<1

28170

<1

EHC Treatment Zone


N

Property Line

0 300 600

SCALE IN FEET

1946

380

650<1

25280

<1

EHC Treatment Zone


N

Property Line

0 300 600

SCALE IN FEET

94140

610

540<1

82190

<1

EHC Treatment Zone


N

Property Line

0 300 600

SCALE IN FEET

150380

610

410<1

2.485

<1

EHC Treatment Zone


N

Property Line

0 300 600

SCALE IN FEET

140

49067

280

4606.4

3798

<1

EHC Treatment Zone


N

Property Line

0 300 600

SCALE IN FEET

LIQUID ISCR CASE STUDIES

38

E-ZVI Case Study

39

May 2016

14

Baseline Concentrations

40

Approach (cont.)

41

Injection design

42

May 2016

15

December 2004 TCEContours

Depth 30-50Feet

April 2008 TCE Depth 30-50Contours Feet

TCE Concentration (ppb)

≥ 10,000 ppb

1,000 ppb

≥ 100 ppb

≥ 10 ppb

Treatment Area

TCE Groundwater Cleanup Target Level is 3.0 ppb

Monitoring Well with Screen Interval

Multi-Chamber Monitoring Well

Case Study #3 – Patrick AFB, Florida RITS Spring 2009: EZVI Treatment of Chlorinated Solvents43

Concord NWS Case Study

Enhanced Reductive Dechlorination Pilot Test:• An Enhanced Reductive Dechlorination (ERD) pilot test

was previously conducted in the TCE source area from 2011 to 2014.

• The ERD pilot test used buffered emulsified vegetable oil substrate which was augmented with dechlorinating microbial consortium (SDC-9™).

ISCR Pilot Study:• The test was conducted in the TCE source area wells

44

• The test was conducted in the TCE source area wells (S29MW01 and S29MW03) not affected by the ERD pilot test.

• The aquifer was first primed for substrate distribution by fracturing the aquifer using the ELS and bioaugmentation solution.

• Following confirmation of fracture development, ZVI suspended in guar was injected into the interval followed immediately by the lactate, ELS solution and bioaugmentation culture.

• Monitoring was then conducted to verify the degradation of TCE.

Analytical Results

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

-100 0 100 200 300 400 500 600

Sta

nd

ard

Un

its

ISCR vs Biotic Only Treatment ComparisonpH

S29MW10 - Biotic Only


S29MW01 - ISCR

S29MW03 - ISCR

-600

-500

-400

-300

-200

-100

0

100

200

300

400

-100 0 100 200 300 400 500 600

mV

ISCR vs Biotic Only Treatment ComparisonOxidation-Reduction Potential



S29MW01 - ISCR

S29MW03 - ISCR

45

Days Days

May 2016

16

Analytical Results

46

Concord NWPS – Total Chlorinated Ethenes

47

Amended and Unamended Field Half Lives

Amended and Unamended Field Half Lives

5,736 5,736 6,648 6,648 6,648

2,112 2,112

456552

41

400

200

400

50

500

200

100

1,000

10,000

alf

Lif

e (h

ou

rs)

CHC (field application rate by weight)

Engineered ISCR‐treated plumes degrade with half lives one to two orders of magnitude faster

than that seen under anaerobic natural attenuation

14

3

14 13

41

2 2 2 2 2

20 20

1

10

PCE (10%) PCE (0.5%) TCE (10%) TCE (1%) TCE (0.5%) Vinyl Chloride(10%)

Vinyl Chloride(1%)

CarbonTetrachloride

(0.5%)

Chloroform(0.5%)

Ha

Anaerobic Natural Attenuation Rates (Alvarez & Ilman, 2006)Injected PRB Field Half LifeTrench PRB Field Half LifeGranular ZVI (Abiotic)

May 2016

17

Latest Developments

1. Integrated Emulsified Lecithin + ZVI

• Full-scale application at Concord NWS in 2014

2. Ferox Plus by Hepure

• ZVI plus emulsified vegetable oil (SRS)

3. Magnetic Susceptibility Analysis

49

• Allows us to determine the capacity of the aquifer to intrinsically support abiotic ISCR

4. Combined Remedies

• Sequential ISCO/ISCR (Klozur Persulfate /EHC)

• ERH/ISCR (CDMSmith, Hunters Point Naval Shipyard)

Bench, Pilot, and Design Optimization Tests

1. Bench tests typically recommended only for unique combination of CVOCs, CVOCs that have not been tested before, CVOCs concentrations outside the previously tested range or unique geochemical conditions (e.g. high sulfate)

2. Pay close attention to how you scale up from bench test data (i.e. the ratio of water to soil used in the bench is usually skewed compared to what it is in the aquifer)

50

3. Perform pilot test to answer questions around distribution, injectability, and full-scale design

4. Pilot test must be small enough to be cost effective, and add value to the full-scale, at the same time broad enough to collect sufficient data. As a general rule, be prepared to collect a lot more data in the pilot then you will during full-scale application

Lessons Learned

1. Geochemistry is important but it is relatively easy to overcome limiting geochemical conditions

2. It is important to know where the majority of the target contamination resides….specially for source and residual source areas

3. Distribution is the key to success, so engage a qualified injection contractor during the design phase

51

contractor during the design phase

4. Adopt newer site characterization tools to optimize implementation and achieve desired goals

5. Employ recommended injection pumps, mixing equipment and procedures

6. Allow flexibility in the design to address unforeseen conditions in the field

May 2016

18

CHAPTER 10IN SITU CHEMICAL REDUCTION FOR SOURCEREMEDIATIONPaul G. Tratnyek,1 Richard L. Johnson,1 Gregory V. Lowry2 and Richard A. Brown3

B.H. Kueper et al. (eds.), Chlorinated Solvent d

Reference Documents

52

Source Zone Remediation,doi: 10.1007/978‐1‐4614‐6922‐3_10, # Springer Science+Business Media New York 2014

Questions???

Ravi Srirangam, Ph.D.Technical Manager, Environmental SolutionsPeroxyChem, LLCOne Commerce Square2005 Market Street, Suite 3200Philadelphia, PA 19103P: 312.480.5250| E:[email protected]/remediation

May 2016

1

Combined Remedies for In Situ Treatment of Contaminants in Soil & Groundwater

Fayaz Lakhwala Ph DFayaz Lakhwala, Ph.D.

1. PeroxyChem Environmental Solutions 2.

Design and Application of In Situ Treatment Technologies

CT/MA

May 2016

Presentation Outline

Combined Remedies Initiative (CRI) – USEPA and National Groundwater Association (NGWA)

Why CRI?

Principles for CRI

Guidelines

2

Combined Remedies ‐ Spatial/Temporal

Combined Remedies – In Situ

Reagents for Combined Remedies

Case Studies

Discussions

Combined Remedies Initiative (CRI) –USEPA and NGWA

•In 2014, USEPA and National Groundwater Association formed a panel of regulators, academicians, consultants and technology vendors to study the application of combined remedies for soil and groundwater treatment

• 2015 Workshops in Boston, Kansas City and Denver

3

•Combined Remedies Sessions at RemTech and Battelle Bioremediation in 2015

•Workshops in Los Angeles and Seattle planned in 2016

•Special Issue of Groundwater & Monitoring Journal on Combined Remedies in 2016

May 2016

2

Why CRI?

The goal of the CRI is to advance the practice of combined remediation

The last 10‐15 years have seen several significant developments:

A larger remediation tool box

Increased awareness that contamination occurs in different phases ‐ e.g., NAPL, sorbed, dissolved

In different sub‐surface compartments – e.g., vadose, transmissive and

4

storage zones

Under different geochemical conditions at the site

All remediation technologies have strengths and weaknesses, which differ from one technology to another

Employing technologies in suitable combination can enable strengths to be combined and weaknesses overcome

This in turn can increase efficiency, improve performance, and thereby save time, money and resources

Principles for PracticingCombined Remedies

While the use of combinations of technologies has become more prevalent, there seem to be opportunities to improve the state of practice

Realization that for many, perhaps most sites, a combination of technologies is likely to be the most suitable remediation approach

Proactive vs Reactive

Clear identification of remedial objectives and metrics that provide guidelines including technology transition points is essential

5

guidelines, including technology transition points, is essential

The selection of each technology should consider how each stage of remedial effort will affect contaminant and subsurface conditions

Inclusion of contingencies in decision‐documents will allow course corrections as new information is generated

Combined remedies can be applied spatially, temporally, or both

In the case of in situ treatment reagents can be combined / reagents engineered to provide multiple treatment pathways

Goal: Develop guidelines to practice application of Combined Remedies

“Ground rules” for selection

Technical basis for integration

Integration benefits

Challenges of managing integration

6

Challenges of managing integration

Contractual certainty vs. the evolving Conceptual Site Model

Technology transition points — the science, the engineering, and the

contract

May 2016

3

Combined Remedies for In Situ Treatment

• In Situ remediation technologies can be broadly grouped into three categories – physical (extraction/thermal), chemical (ISCO/ISCR) and biological (ISB/MNA)

• Generally speaking, these groups commonly exhibit their greatest efficiency t hi h di d l t i t t ti ti l

Practitioners Principles

7

at high, medium and low contaminant concentrations, respectively

• Their combined usage may therefore similarly follow the physical, chemical, biological sequence as remediation progresses and concentrations are reduced

What, When, Where and How?

8

Combined Remedies - Spatial

Source Area ‐ Unsaturated Zone

•Excavation, ISCO w/soil mixing, Soil Vapor Extraction (SVE) , Bioventing

Source Area ‐ Saturated Zone

•Excavation, soil mixing, Air sparging ‐ Soil Vapor Extraction (AS/SVE), Multi‐phase Extraction (MPE), Dual‐Phase Extraction (DPE), Thermal, ISCO, ISCR, In Situ Bioremediation (ISB), In Situ Solidification/Stabilization (ISS)

Pl A (R id l S Z / Di l d Ph Pl

9

Plume Area (Residual Source Zone/ Dissolved Phase Plume

•Pump and Treat (P&T), AS/SVE, DPE, ISCO, ISCR, ISB, Phytoremediation, Monitored Natural Attenuation (MNA)

Off‐Site Migrating Plume

•P&T, Permeable Reactive Barriers (PRBs), MNA

May 2016

4


10


11

Transport in saprolite and bedrock

Max TCE concentration 1,200 mg/L

Very little biodegradation

14.8 acres


ZVI Injection

KMnO4

Injection

12

ZVI Injection

KMnO4

Injection

110 ft

May 2016

5


13


14


15

May 2016

6


Primary Injection ( Aug 2013)

7 New borings

29 Injection intervals

21 Saprolite

5 Transition

3 Bedrock

38.3 Tons KMnO4/sand blend

Supplemental Injection (July 2014)

16

Supplemental Injection (July 2014)

10 Injection wells

5 New

5 Existing


33 Saprolite

4 Transition

11 Bedrock

31 Tons KMnO4/sand blend

Scale = 40 ft


17

15 Monitoring wells:

• 8 are ND

• 4 are >99.9% reduction from July 2014

• 3 are 88.6-99.9% reduction from July 2014


18

May 2016

7


3 PRBs (508’, 441’, 219’)

62 Borings

652 Tons ZVI


157 Saprolite

106 T iti

19

106 Transition zone

105 Bedrock


20


21

May 2016

8


22

Combined Remedies – Temporal

ISCO can be used as a mass reduction technology followed by: In situ bioremediation In situ biogeochemical remediation In situ chemical reduction Monitored natural attenuation

23

ISCO can be used following: Thermal treatment Surfactant/solvent enhanced extraction Extraction systems (dual phase extraction)

ISCR can be used as a mass reduction technology followed by: In situ bioremediation In situ biogeochemical remediation Monitored natural attenuation

In Situ Combined Remedies: Transition Points

Asymptotic trend in contaminant concentration

Reach order of magnitude (OOMs) reduction in contaminant mass or contaminant concentration

Shift in geochemical conditions to support the next step in the

24

g pp ptreatment train

Treatment of partial suite of contaminants is achieved…… the rest has to be treated by an alternative method

May 2016

9

In Situ Combined Remedies: Products that Promote Multiple Treatment Pathways

Klozur‐CR ®

Oxidation, aerobic degradation and anaerobic degradation

Applicable for mixed CVOCs and TPH contamination

EHC ®, DARAMEND ®, EHC® Liquid, Ferox Plus ™, EZVI

Ch i l d ti d bi bi d d ti f CVOC

25

Chemical reduction and anaerobic biodegradation of CVOCs

EHC®Metals, MetaFix ®

Chemical reduction and anaerobic biodegradation of CVOCs and Metals

BOS 100 ® , BOS 200 ®, PlumeStop ®

Aerobic and anaerobic bioremediation with adsorption

Chemical reduction with adsorption

gw flow

Injection Zone:

•Chemical oxidation (2‐3 months):source mass removal

• Extended elevated dissolved O2 for up to a year supports aerobic bioremediation

Klozur® CR Coupling ISCO with Bioremediation

Klozur CR Composition:

• 50% Klozur persulfate

• 50% PermeOx Plus

MechanismsContaminant plume

26

source polishing

Down gradient effects:

• dissolved O2 aerobic bio

• sulfate + dissolved organic fragments anaerobic oxidation

59‐01‐EIT‐DL

Conceptual Timeline

Persulfatechemical oxidation

Oxygen releaseaerobic bioremediation

Residual sulfateanaerobic oxidation

Sulfate Enhanced Biodegradation

27

May 2016

10

Effect of Klozur-CR on Contaminant Oxidation, Sulfide Production and Cinnabar (HgS) Precipitation.

Klozur-CR study conducted by Western Michigan University

Three different doses of Klozur®CR (persulfate activated with calcium peroxide) were added to slurry reactors containing sediment from the Kalamazoo River Superfund site contaminated with PAHs, PCBs, and mercury (in methylated and inorganic form)

28

The three test reactors and a control reactor were maintained for a period of 20 weeks

The purpose of these studies was to investigate the affect of Klozur-CR on indigenous sulfate-reducing bacteria (SRB) and chemical oxidation of PAHs, PCBs, and methylmercury (MeHg),

And on the ability of SRB to produce sulfide and precipitate cinnabar (HgS) after persulfate oxidation


29


30

May 2016

11


31


32


Conclusions

Klozur‐CR was effective at chemical oxidation of the contaminants in the sediments tested, removing 91% of PCBs and 88% of PAHs at the highest dose tested (20 g/kg sediment). All doses removed over 99% of the MeHg in the sediments, and after 20 weeks

The results from the measurements of most probable number (MPN) and the relative abundance (RA) of oligonucleotide probes of SRB in the sediments clearly h h l l kill d i hibi d b ddi i f l ®

33

show that SRB were not completely killed or inhibited by addition of Klozur®CR

In fact, after an initial decrease in MPN, the lowest dose of Klozur®CR resulted in a higher MPN of SRB relative to the control

Within weeks after the exhaustion of the persulfate, sulfide was produced by the activity of the SRB. This resulted in precipitation of significant amounts of cinnabar (HgS)

May 2016

12

Case Study – Combined ISCO/ISCR

Optimization of In Situ Chemical Oxidation and Enhanced In Situ Bioremediation to Treat a Dilute Chlorinated Solvent Plume

Stephen Rosansky and Ramona Darlington (Battelle, Columbus, Ohio, USA)Heather Rectanus and Deepti Nair (Battelle, San Diego, California, USA)Brant Smith (XDD, Stratham, New Hampshire, USA)

34

Lora Battaglia (Navy BRAC PMO, San Diego, California, USA)

A‐71, in: H.V. Rectanus and R. Sirabian (Chairs), Bioremediation and Sustainable Environmental Technologies—2011.International Symposium on Bioremediation and Sustainable Environmental Technologies (Reno, NV; June 27–30, 2011).ISBN 978‐0‐9819730‐4‐3, Battelle Memorial Institute, Columbus, OH. www.battelle.org/biosymp

35

36

May 2016

13

37

38

39

May 2016

14

40

41

42

May 2016

15

43

44

Biogeochemical Formation of Reactive Iron Sulfide Mineralsat Hickam AFB, Pearl Harbor HI

• Unconsolidated calcium carbonate aquifer• Ambient aerobic groundwater• Very high sulfate concentrations (up to 3,000 mg/L)• Very high concentrations of chlorinated ethenes

(PCE,TCE, DCE,VC) (up to 550 mg/L TCE)• Efficient dechlorinating microbial culture present• EVO pilot test established reducing conditions but result was incomplete dechlorination, accumulation f DCE d VC d littl th ti

45

of DCE and VC, and very little ethene generation.

Daniel Leigh for AFCEE, 2011

• Change to ISCR treatment with organic substrate (lactate) and ferrous iron

• Examination of mineral precipitates one year after application of treatment

• Electron microprobe analyses of the precipitates (elemental characterization of newly‐formed minerals after 1 year)

May 2016

16

FeS present as fine (ca. 3 - 5 µm) coatingIs this important?

46Daniel Leigh P.G. CH.G. for AFCEE, 2011

Estimate: each 1.0 L of groundwater with sulfate at 3,000 mg/L reduced to 3.0 µm thick FeSprecipitates will yield about 1.2 ft2 of very reactive surface – YES, it is important!

How long will reactive minerals last? Influence of pH on Fe+2 release from FeS

47Hayes et al., 2009. SERDP ER-1375

Upflow columns packed with FeS coated sand. Effluent Fe+2 between 1 µg/L and 5 µg/L indicates that thin layers of FeS will last for 16 years under the pH 5.5 condition and 15 cm/day GW velocity. About 2% Fe released over 60 PV.

Evaluation of In Situ Chemical Reduction to Treat Chlorinated Ethenes in High

Sulfate Aquifers

48

Contaminated Site Management: Sustainable

Remediation and Management of Soil, Sediment and Water 2014

Daniel Leigh, Daniel E. Johnson and Keith L. Etchells

May 2016

17

High Sulfate Aquifer

• Large built structures prevent access to plume ( 500’ wide mall, street, garage) and make remediation infrastructure expensive

• Low seepage velocity challenging for passive treatment and active both. PRB longevity considerations in design

• Elevated PCE >2000 μg/L

Site Conditions/Constraints

49

• Aerobic Aquifer (DO ~5.0 mg/L)• Sulfate up to 3,000 mg/L• Previous bio only pilot tests unsuccessful• Incomplete degradation of PCE• Potential sulfide inhibition• Skeptical regulators: enhanced reductive dechlorination not

viewed feasible or applicable based on different technology

Objective

Determine if In Situ Chemical Reduction (ISCR) is capable of Treating PCE in aerobic, high sulfate aquifer

Determine if of soluble ferrous iron in EHC®‐Liquid can enhances precipitation of iron sulfide.

50

Does removal of sulfate/sulfide result in dechlorination of PCE?

Approach: Conduct bench test to evaluate two ISCR products

EHC®

EHC®Liquid + Soluble Fe2+

EHC-Liquid: Reaction Chemistry

Like EHC, EHC-L supports degradation of organic constituents by enhancing:

anaerobic bioremediation processes abiotic reduction reactions

Iron reducing microbes will continuously regenerate ferrous minerals and a cycle is

As bacteria feed on the soluble carbon, they consume dissolved oxygen and other electron acceptors, thereby reducing the redox potential in groundwater.

51

The soluble carbon provides molecular hydrogen (H2) for biologically mediatedenhanced reductive dechlorination (ERD)

Fe+2 Fe+3

Bacterial extraction of electrons from carbon restores Ferric (Fe+3) to Ferrous (Fe+2)

e‐

ISCR reactions of Fe+2

with contaminants andformation of Fe+3

PCE Ethene

Ferrous iron may also control dissolved phase heavymetals by promoting formation of insoluble forms (e.g.,arsenopyrite from arsenic).

established.

The soluble ferrous iron (Fe2+) combines with sulfide (S‐) togenerate reactive iron sulfide (FeS) species in situ

May 2016

18

Microcosm Setup

Sulfate – 1,800 mg/L Spiked to 2,300 mg/L

PCE – 170 μg/L Spiked to 1,800 μg/L

SDC‐9TM Dhc ~ 1X108 cells/L

Sediment and groundwater samples collected from source area wells

Bench Test Conducted at PeroxyChem’s laboratory Mississauga, ON

52

EHC‐Liquid 10 g/L + additional 14 g/L soluble iron

EHC – 10 g/L

Precipitation of Sulfide

Day 6

EHC‐LEHCControl

Day 34

EHC‐LEHCControlEHCEHC‐L

53

Day 60

EHC EHC‐LControl

Day 124

EHC‐LEHCControl

Day 182

EHC EHC‐LControl

Precipitation of Sulfide

54

May 2016

19

Analytical Results

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

0 50 100 150 200

pH (Units)

pH

Control

EHC

EHC‐L +Fe2+

‐600

‐400

‐200

0

200

400

600

0 50 100 150 200

MilliVolts

ORP

Control

EHC

EHC‐L +Fe2+

55

0

500

1,000

1,500

2,000

2,500

3,000

0 50 100 150 200

Concentraation )mg/L)

Days

Sulfate

Control

EHC

EHC‐L +Fe2+

0 50 100 150 200Days

0 50 100 150 200Days

0

1

2

3

4

5

6

7

8

0 50 100 150 200

Concentration (mg/L)

Days

Nitrate

Control

EHC

EHC‐L +Fe2+

VOC Analytical Results

0

5

10

15

20

25

30

35

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

0 100 200

Concentration ethne, ethane,

acetylene (μg/L)

Concentration PCE, TCE, DCE VC

(μg/L)

EHC ‐Mass Concentration

0

2

4

6

8

10

12

0 50 100 150 200


(μMol/L)

EHC ‐Molar Concentration

56

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

0 50 100 150 200

Concentration ethne, ethan

e,

acetylene (μg/L)


(μg/L)

Days

EHC Liquid + Fe2+ ‐Mass Concentration

0

2

4

6

8

10

12

0 50 100 150 200


(μMol/L)

Days

EHC Liquid + Fe2+ ‐Molar Concentration

0 100 200

Days Days

FeS Precipitation and Summary

FeS does not fill pore space

0.56 cm3 Mackinawite (FeS, 4.9 g/cm3) ~0.05% of volume of pore space

0.38 cm3 Pyrite (FeS2, 4.8 to 5.0 g/cm3) ~ 0.04% of volume of pore space

Reduction of 1 Liter of 3,000 mg/L of sulfate and precipitation as ferrous sulfide produces:

Significant reductions in hydraulic conductivity would not be expected from FeSprecipitation

57

precipitation

Addition of EHC and EHC‐Liquid will reduce sulfate to sulfide

Sulfide precipitates as ferrous sulfide

Removal of sulfate and sulfide allows for complete reductive dechlorination of PCE

FeS promotes biogeochemical degradation of chlorinated ethenes

ISCR is a highly effective process for treating chlorinated ethenes in high sulfate aquifers

May 2016

20

First Order Rate Constants for Reactive Iron and Sulfur Minerals

58

Degradation of carbon tetrachloride on reactive iron and sulfur minerals in laboratory experiments. The pseudo first order rate constant is normalized to the concentration of the mineral (units of L g-1 day-1) or to the surface area of the mineral presented to water (L m-2 day-1).

In Situ Biogeochemical Transformation (ISBGT)

59

Source: James Studer, InfraSur, LLC. The Biogeochemical Reductive Dehalogenation (BiRD) Groundwater Treatment Process: Presented at the FRC, Orlando, FL Oct 2015


60


May 2016

21


61



62


Oxygen O2 + 4H+ + 4e- 2H2O (Eh0 = +820)

Nitrate 2NO3- + 12H+ +10e- N2(g) + 6H2O (Eh

0 = +740)

Released

During ElectronTran

sfer

Manganese (IV) MnO2(s) + HCO3 +3H + + 2e ‐ MnCO3 (s) + 2H20

(Eh0 = +520)

d i l ( h0)

500

Aerobic

Anaerobic

1000

Arsenic (V) H3AsO4 + 2H+ +2e‐ H3AsO3 + H2O (Eh

0 = +559)

Chromium (VI ) Cr2O72- + 14H+ + 6e- 2Cr3++7H2O (Eh0 = +1330)

Anaerobic

ClO4− + 4H2O + 8e

− → Cl− + 8OH− (Eh0560)Perchlorate

Eh range for cholorinated ethene degradation

Range for EffectiveChlorinated Ethene

Degradation(chlororespiration)

↓Methanogenesis CO2 + 8H

+ + 8e‐ CH4 + 2H2O (Eh0 = ‐240)

Sulfate SO42‐ + 9H+ + 8e‐ HS‐ + 4H2O (Eh

0 = ‐220)

Iron FeOOH(s) +HCO3‐ + 2H+ e‐ FeCO3 + 2H2O (Eh

0 = ‐50)

Decreasing Amount of En

ergy R Redox Potential (Eh0)in Millivolts @ pH = 7

and T = 250C0

-250

0

PCE TCE

TCE DCE

DCE VC

VC Ethene

May 2016

22

H2 demand for select electron acceptors

Electron Acceptor Electron equivalents per mole

Oxygen 4

Nitrate 4

Sulfate 8

Carbon dioxide 8

64

Manganese (IV) 2

Ferric iron (III) 1

PCE ‐ tetrachloroethene 8

TCE – trichloroethene 6

DCE – dichloroethene 4

VC – vinyl chloride 2

Most CE mass may be attached to aquifer matrix

MetaFix® Reagents

MetaFix® is a new family of reagents designed to treat heavy metals in soil and groundwater using chemical reduction, precipitation, and adsorption.

Reagents do not rely on biological sulfate reduction or carbon metabolism so their performance is not inhibited by high toxicity (e.g., alkalinity, acidity, salts, high COI concentrations)

65

Composed of ZVI, iron sulfides, iron oxides, alkaline earth carbonates, and activated carbon

Treatment results in conversion of aqueous heavy metals to low solubility mineral precipitates with broad pH stability

Can also treat cVOCS via abiotic pathways

Unique made-to-order formulations for all commonly found metallic contaminants and site conditions

Composition of MetaFix® Reagents

ZVI: reductant, source of Fe+2

Iron Sulfides: source of sulfide and Fe+2, catalyst, provide both cationic and anionic adsorption surfaces, can make aqueous iron more reactive

Iron Oxides: provide both cationic and anionic surfaces, adatoms of ferrous iron are very reactive

66

CaCO3: pH balance and source of carbonate

Activated Carbon: strong adsorbent for organically-bound metals including arsenic, mercury, and nickel

Supplementary reagents: ion exchange, pH modification when needed, inclusion based on results of bench-scale optimization work

May 2016

23

Fe0.75Cr0.25(OH)3

Aqueous Solubilities of Heavy Metal Hydroxides, Iron Hydroxides, and Sulfides

67

EPA 625/8-80-003, 1980; Banerjee et al., 2013. Veolia Water Inc. Environ. Sci. Technol. 1988, 22, 972-977

Independent Evaluation of MetaFix Phase II Chromium Results: MetaFix

1,000

10,000

100,000

ntration [µg/L]

Bench‐scale Column Study Results SummaryMetaFix(TM) Column Cr+6 Concentration [µg/L]

68

10

100

InfluentMid‐Column

Effluent

Concen

Day1 Day3 Day6 Day9 Day12 Day16 Day19 Day20 Day21 Day22

Day23 Day24 Day 25 Day28 Day32 Day40 Day50 Day60 Day70

Independent Evaluation of MetaFixPhase II Nickel Results: MetaFix

1,000

10,000

ntration [µg/L]

Bench‐scale Column Study Results SummaryMetaFix(TM) Column Ni Concentration [µg/L]

69

10

100

Influent

Mid‐Column

Effluent

Concen

Day1 Day3 Day6 Day9 Day12 Day16 Day19 Day20 Day21 Day22

Day23 Day24 Day25 Day28 Day32 Day40 Day50 Day60 Day70

May 2016

24

Treatment of Mixed Metal/cVOC Plumes

Table 1. Influence of control and treatment on heavy metal concentrations.

Biotic Control

70Confidential Client, Independent Laboratory

MetaFix® I‐6

Mixed Metal/cVOC Plumes

Table 1. Influence of control and treatment on VOC concentrations in microcosms.

Biotic Control

71Confidential Client, Independent Laboratory

MetaFix® I‐6

Where do we go from here on CRI ?

•Identification of Best Management Practices (BMPs) – e.g., insights into opportunities for coupling technologies and indicia regarding transition points

•Identification of barriers ‐ informational, institutional, etc. ‐ to the use of combinations of technologies

Areas of possible contributions to the state of practice include:

72

•Identification and support of research for improved understanding of technology suitability and exploitation of synergies

•Publication of useful case study and research paper information and dissemination via appropriate multi‐media mechanisms

May 2016

25

Fayaz Lakhwala, Ph.D.Technology Applications Manager|Environmental SolutionsPeroxyChem, LLCOne Commerce Square2005 Market Street, Suite 3200Philadelphia, PA 19103P: 908.230.9567| E:[email protected]/remediation

Questions ?

p y

May 2016

1

High Resolution Remediation

Eliot CooperDirector of [email protected]

303‐669‐7443

1

303‐669‐7443

Design and Application of In Situ Treatment TechnologiesCT/MAMay 2016

Success is enough of chemistry cost effectivelydelivered in contact with contaminants for a longenoughperiod of time for effective destruction.

There is a Methodology For Success

2

“Contaminant Mass” => Chemistry matters

“Contact” => HRSC matters

– ID of lithology vs. contaminant mass vs. K < 1” resolution

What Really Matters?

resolution

“Delivered” Lithology Matters

– Fracturing and Injection

“Long Enough Period Time” => Residence Time Matters

– Seepage Velocity (K and gradient)

3

May 2016

2

Why High Resolution Site Characterization Matters

Moving On FromMonitoring Wells

• Monitoring Wells (MWs) yield depth‐integrated, flow‐weighted averaged data, with no vertical distribution of contaminants in the screened interval.

• Monitoring wells are holes in the ground that lie.

• MWs and 5 foot soil cores do not define the small scale heterogeneities controlling contaminant transport.

5

“Too Expensive”

Cost of an investigation that includes HRSC may be hi h h i l i i i i i i ll b h

Dispelling HRSC Myths

higher than a typical investigation initially, but the overall cost of the project will be lower due to:

• Reduced investigation phases

• More focused, appropriate, and cost effective remedy

6

May 2016

3

“Only for the most complex sites”

All sites can benefit from HRSC; the complexity

Dispelling HRSC Myths

of most sites is not known until many mobilizations have occurred using traditional

site characterization technologies

7

Remedies based on a flawed CSM may not perform as expected, increasing the time it takes to achieve remedial action objectives, and the

Risks of Faulty CSMs

j ,overall cost. Until the CSM reflects reality, investigation and cleanup will be costly.

8

HRSC Tools ‐ General

• Advanced with direct push technology

• Rugged equipment down‐hole and sensitive equipment above ground

• Provides vertically dense data in strip log format

• Results are in real time to support dynamic work planning

• Data is mobile ‐ email

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May 2016

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High Resolution Characterization Technology Continually ImprovingProblem Solution

Inability of MIP to map VOC mass to K in same push

MiHPT

Inability to speciate PCE/TCE from DCE/VC with MIP

XSD/ECD

Need lower MIP detection limits for plume

Low Level MIP

DNAPL, LNAPL foul trunk lines Heated Trunk Line

Accurately collecting confirmation gw samples based on K

HPT Groundwater Sampler

Inability to see SVOCs NAPL with MIP

UVOST

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MiHPT System

11

MiHPT –Membrane Interface Hydraulic Profiling Tool

• Providing the Whole Picture

– Lithology: Electrical Conductivity (EC)(EC)

– VOC Mass: Membrane Interface Probe (MIP)

– Hydraulic Conductivity: Hydraulic Profiling Tool (HPT)

• 3 Tools – One Boring

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May 2016

5

MIP Log

-High EC: Fine grained soil-Baseline Response: No CVOC Mass Or < Detection Limits

EC mS/m XSD 1 x 105

MV

EC XSD

13

Limits

-Lower EC: Some course grained soil-MIP Detector Response: CVOC Mass Located in this Zone

HPT Log EC HPT Pressure

K HPT Log

EC Pressure Flow

14

MiHPT Log

-Lower EC-Lower HPT Pressure-No Hydrocarbon Mass-Higher K

EC HPT Pressure

KPID

Depth to GW

EC Pressure PID K

15

-Higher EC-Higher HPT Pressure-Hydrocarbon VOC Mass-Lower K

May 2016

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Dissipation Test

HydraulicConductivity

16

3D Imaged Source Area – PID > 1 x 106 microvolts

Evolution of HRSC

May 2016

7

Search and Destroy® Alive and Well

EC 0-150 ms/m PID 0-6 107 uV EC 100 – 1600 ms/m PID 0.1 – 2.5 106 uV

MiHPT Performance Monitoring

• NC Former retail gas station• Original design based on MW and

limited soil data• HRSC (MIP) and pilot testing

performed in same mobilization (4 days onsite)

HRSC Optimization Case Study

– SOD (0.5 g/kg) and buffering samples collected

– Injection tooling selected and distribution verified (using EC)

• Two full scale rounds of caustic ASP completed to date– 10‐15% SP, 75% mobile pore volume

20

HRSC Source ID

MW‐18

MW‐5

MW‐8

Former USTs

Approximate Well Screen

(10-20 ft)

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May 2016

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Targeted Injection Plan

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Project Summary

23

Delivery – Why Lithology Matters

May 2016

9

Lithology Specific Delivery Approaches

Scenario Tooling Screen Lengths

HomogeneousSands/Gravels

Wells or DPT 5 to 30 feet

HeterogeneousSands, Silts and

Top‐DownDPT

1 Foot

Clays

Silts and Clays Top Down ‐DPT

Fracturing

Sands Over Clays Bottom‐UpDPT

Fracturing

Clays Over Sand Top –Down DPT

Fracturing

Bedrock Wells, Open Bore Holes w Packers

5 to ?? Feet

DPT Tooling Retractable

26

DPT Tooling 1.5 – 2.25” Fixed Open

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May 2016

10

DPT Tooling Inner‐Hose

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DPT Fracturing

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DPT Injection Profile> Fracture Pressure

200 20

175 17.5

150 15

125 12 5

Flow Rae

PSI

Fracture Pressure

30

125 12.5

100 10

75 7.5

50 5

25 2.5

0 0

0 5 10 15 20 25 30 35 40

ate GPM P

ressure

Maintenance Pressure

Time Minutes

May 2016

11

DPT Rule Of Thumb

PImax = (DTI * 0.5PSI) + DTPc

DPT Injection < Fracture Pressure

DTI = Depth To Target Interval

DPTC = DPT Compaction Factor

DPTC= 0 to 75 PSI per soil type

31

DPT Injection Profile< Fracture Pressure

200 20

175 17.5

150 15

125 12 5

Flow Rae PSI

DPT Compaction Pressure

32

125 12.5

100 10

75 7.5

50 5

25 2.5

0 0

0 5 10 15 20 25 30 35 40

ate GPM P

ressure

Time Minutes

DPT Compaction Pressure

Compacted Zone Degrading

HRIT – Do You Need To Fracture

• Real‐Time High Resolution Injection Data:

– Electrical Conductivity

– Flow

– Up‐Hole Pressure

– Down‐Hole Pressure

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May 2016

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0123456789

14:10:53

11:21:42

11:23:21

11:25:03

11:26:43

11:28:24

11:30:04

11:31:42

11:33:25

11:35:06

11:36:45

11:38:25

Flow (GPM)2

0

10

20

30

40

50

60

14:10:53

11:21:42

11:23:21

11:25:03

11:26:43

11:28:24

11:30:04

11:31:42

11:33:25

11:35:06

11:36:45

11:38:25

Pressure Switch Above Ground (PSI)

0

5

10

15

20

25

14:10:53

11:21:42

11:23:21

11:25:03

11:26:43

11:28:24

11:30:04

11:31:42

11:33:25

11:35:06

11:36:45

11:38:25

Down_Hole Pressure

HRIT DPT – Target Interval Fracture AnalysisEstimated Vs Actual Down Hole Data

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0

1

2

3

4

5

6

7

8

9

0

10

20

30

40

50

60

14:10:53

11:21:42

11:23:21

11:25:03

11:26:43

11:28:24

11:30:04

11:31:42

11:33:25

11:35:06

11:36:45

11:38:25

Down_Hole Pressure Pressure Switch Above Ground (PSI) Flow (GPM)2

FLOW

(GPM)

PRESSU

RE (PSi)

Why Residence Time Matters

Contaminant mass distribution is based Water-Soil Equilibrium Partition theory….the ability of organic carbon in soil to absorb contamination.

35

Advection / Dispersion ROI

Additional ROI from Advection

/ Dispersion (Feet)

0.5 foot/day

Time Frame To Achieve


(Days)

ROIInjectable Pore Volume ROI

% of Injectable Volume

Pore Volume ROI

Reagent

Per Location + =

Vironex ROI CalculationsAssuming Darcy Flow High Seepage Velocity

8 feet 16 Days 11.5 feet20% 3.5 feet1675 gals

11.5 feet = 3.5 feet + 8 feet @ 16 days

23 ft

15’

Reagent Persistence > Kinetics ROI

May 2016

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Additional ROI from Advection

/ Dispersion (Feet)

1 foot/month

Time Frame To Achieve


(Days)

ROIInjectable Pore Volume ROI

% of Injectable Volume

Pore Volume ROI

Reagent

Per Location + =

Vironex ROI CalculationsAssuming Darcy Flow Low Seepage Velocity

8 feet 8 months 11.5 feet20% 3.5 feet1675 gals

11.5 feet = 3.5 feet + 8 feet @ 240 days

23’

15’

Reagent Persistence > Kinetics + ROI

ROI Design Considerations

ROI = Radius Of InfluenceROIT = Time To Achieve Radius Of InfluencePVI = % Pore Volume To Be InjectedGWSV = GW Seepage VelocityDGWSV = Distribution By GW Seepage VelocityT Ti R t Ki ti ll A ti

DesignRequirement

ROIT > Tk ROIT < RT

ROIT = TKROIT = RT

COCsUntreated

COCsUntreated

Chemistry ROIT > Tk ROIT < RTTK = Time Reagent Kinetically ActiveRT = Time To destruct Contaminant

PVI = ROI – DGWSV

ROIT = ROI‐PVI / GWSV

e s y O T k O T T

ISCO, Bio, ISCR

> Persistence > Persistence

Delivery ROIT > Tk ROIT < RT

Liquid Vs Solid

Inject Vs Fracture

Inject Vs Fracture

Grid Vs Barrier Vs Recirculation

Inject Vs Fracture

Inject Vs Fracture

Typical Spacing

High Seepage Velocity Impact on Spacing

10’ ROI @ 30% pore Volume

Advection Driven

Tighter spacing between points and larger spacing between rows.

May 2016

14

Key Takeaways

Chemistry selection and delivery are dependent on:

1. Contaminant type and mass distribution in relation to lithology and seepage velocity

2. Liquids can be injected effectively once target intervals are understood and seepage velocities and advective flow support reagent kinetics and residence times for grid or barrier applications

3. Solids can be fractured effectively once target intervals are understood and lithology or seepage velocities support grid or barrier applications

We Have Our Work Cut Out for Us

• Region 9 has adopted a short-term exposure guideline for TCE that assumes there is a teratogenic impact from TCE.

• The short-term exposure guidelines require “urgent” responses,

41

p g q g p ,including the possibility of evacuation, to concentrations as low 6 µg/m 3 in residences and 21 µg/m3 in commercial buildings for a ten hour shift.

• All of these actions are being taken by EPA Region 9 notwithstanding the lack of a uniform policy or nationwide standard equally applicable to all of the approximately 1,300 Superfund sites in the U.S.

ROI Exercise ‐ QuestionProject Name:

Date:

Site Info:

Treatment Area 80 by 55 = 4,400 ft^2

Treatment Interval to = 0 ft

% of Treatment Interval Injectable

Effective Porosity 30%

Mobile Porosity 20%

Vironex Workshop Training

Mobile Pore Volume 0 gal 7.48 gallons per cubic Foot

Injection Design Specifications:

Injection Volume gal

Radius of Influence (ROI) 10 ft

% Mobile Pore Volume Injected Achieve 25%

Number of Injection Locations

Volume/Location gal

Calculation Assumptions:

1.) Injection pressure is kept below the fracture pressure. Fracture pressure can be determined using the High Resolution Injection Tool (HRIT)

2.) The non‐transmissive zones are not targeted for remediation. If fracturing is necessary, see Fracturing ROI tab

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May 2016

15

ROI Exercise ‐ Question

43

ROI Exercise ‐ Answer

Target Interval 26’ to 31’

75% Injectable< 50 PSI

44

ROI Exercise ‐ Answer

Site Info:

Treatment Area 80 by 55 = 4,400 ft^2

Treatment Interval 26 to 31 = 5 ft

% of Treatment Interval Injectable 75%

Effective Porosity 30%

Mobile Porosity 20%

Mobile Pore Volume 24,684 gal

Seepage Velocity Calculation:

Hydraulic Conductivity (K) 50 ft/day

Gradient 0.001 ft/ft

Estimated Seepage Velocity 61 ft/yr

Injection Design Specifications:

Estimated Reagent Persistence 30 days

Injection Volume 6,275 gal

Radius of Influence (ROI) 10 ft

% Mobile Pore Volume Injected 25%

Number of Injection Locations 15

Volume/Location 418 gal

Distribution Assessment Calculations:

Injection Flow Distance 4.9 ft

Advective Flow Distance 5.0 ft

Total Flow Distance 9.9 ft

Ratio of Total to ROI 0.99

Injection Flow + Advective Flow > Design ROI? Yes

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May 2016 - EPOC

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