Aquifer Solutions, Inc. Clarkson University · Definitions and ISCO Fundamentals (cont.) •...

Is ISCO Right for Your Site?Is ISCO Right for Your Site?gg

Michelle CrimiMichelle CrimiClarkson University Clarkson University

Fritz KrembsFritz KrembsAquifer Solutions, Inc.Aquifer Solutions, Inc.

RITS Fall 2010

*In Situ Chemical Oxidation (ISCO)

SDMS DOCID#1142175

Presentation Overview

• Introduction to ISCO

• ISCO Technology Practices Manual (TPM):ESTCP Project Background and Overview of Results

• ISCO Screening

ISCO Conceptual Design• ISCO Conceptual Design

• ISCO Detailed Design, Implementation, and Monitoring

• Case Studies

• Summary

2

• Summary

RITS Fall 2010: Is ISCO Right for Your Site?

Definitions and ISCO Fundamentals

• ISCO: In situ chemical oxidation (formerly ChemOx)– Delivery of oxidants into the subsurface to destroy contaminants

in groundwater

– Chemical reactions occur primarily in aqueous phase though some treatment of NAPL and sorbed phases may occur

• COCs: Contaminants of concern

• NAPL (DNAPL): non-aqueous phase liquid (dense) ( ) q p q ( )

• NOD/SOD: natural or soil oxidant demandM f id t d f di t t d

3

– Mass of oxidant consumed per mass of media contacted

RITS Fall 2010: Is ISCO Right for Your Site?Introduction to ISCO

Definitions and ISCO Fundamentals (cont.)

• Chemical oxidants can rapidly destroy many contaminants of concern (COCs)co ce (COCs)

– Chlorinated hydrocarbons, fuel related compounds, phenols and PAHs, energetics, pesticides, etc.El t t f– Electron transfer C2HCl3 + 2MnO4

- 2MnO2 + 3Cl- + 2CO2 + H+

– Free radical oxidation Fe2+ + H2O2 Fe3+ + OH- + OH●

• Common oxidants• Common oxidants– Permanganate (electron transfer)– Activated persulfate (free radical)Activated persulfate (free radical)– Catalyzed hydrogen peroxide (CHP or Modified Fenton’s reagent)

(free radical)O (b h l f d f di l)

4

– Ozone (both electron transfer and free radical)



• Oxidant Dose: ISCO design parameter R ti f f id t d li d t f l i di i t t t – Ratio of mass of oxidant delivered to mass of geologic media in treatment zone, typically reported in units g oxidant/kg of treatment zone

• Pore Volumes (PVs) Delivered: ISCO design parameter – Ratio of volume of oxidant solution injected to volume of pore space in

treatment zone, unitless parameter

T t t l• Treatment goals– MCLs: Maximum contaminant levels (EPA or state regulatory levels)– ACLs: Alternative Concentration Limits (risk-based)ACLs: Alternative Concentration Limits (risk-based)– Mass flux: Rate of contaminant release from a source zone (mass discharge)– Percent concentration or mass reduction

5 RITS Fall 2010: Is ISCO Right for Your Site?Introduction to ISCO


• TPM: Technology Practices Manual– Funded by ESTCP to enable more predictable, cost-effective

application of ISCOWill be available at SERDP/ESTCP Web site– Will be available at SERDP/ESTCP Web site

• DISCO: Database for ISCO • ISCO Protocol components

– ISCO Screening– ISCO Conceptual Design– ISCO Detailed Design and Planning

6

– ISCO Implementation and Performance MonitoringIntroduction to ISCO RITS Fall 2010: Is ISCO Right for Your Site?


• Application of ISCO requires delivery of oxidants into and throughout a target treatment zone (TTZ) t oug out a ta get t eat e t o e ( )

– Delivery methods • Direct-push probes, drilled wells, or specialized injectors, with some use of fracturing

or mixing techniques; Reactive barriers recirculation schemes multiple delivery or mixing techniques; Reactive barriers, recirculation schemes, multiple delivery modes, or other strategies

– Viability of a given delivery method depends on the oxidant used and site-specific conditionssite specific conditions

• Remedial action objectives and site cleanup goals have varied– Reduce the concentration or mass by some percentage (e.g., ≤90%)Reduce the concentration or mass by some percentage (e.g., ≤90%)– Achieve a target concentration (e.g., ≤100 µg/L or ≤1 mg/kg)– Achieve a concentration in a plume at some compliance plane

d di t f

7

downgradient from a source zone


ISCO Performance

• At some sites, clean up goals have been met in a di t bl t ff ti d ti l i ISCOpredictable, cost-effective and timely manner using ISCO

• At other sites, ISCO performancehas not met expectations

– Inability to achieve site cleanup goalsbased on predictions for the ISCOsystem that was designed andimplementedp e e ted

– So-called “rebound” in groundwaterconcentrations following the end of

8

active ISCO operations


Reasons for Poor Performance

• Poor performance is often attributed to…Site heterogeneities and low permeability zones– Site heterogeneities and low permeability zones

– Excessive oxidant consumption by soil and aquifer media– Presence of large masses of contaminants (e.g., NAPLs)Presence of large masses of contaminants (e.g., NAPLs)– Poor design: Insufficient oxidant DOSE or VOLUME

• Example regulator comments on ISCO case studyp g y– “Residual DNAPL in the soil appears to inhibit the

success of the injected solutions.”“Th h t b d d ti Actual Injection– “The source has not been removed and continues as a source for groundwater contamination.”

– “Insufficient quantities of [ISCO product trade name]ma limit the s ccess of the treatment ”

Actual Injection Conditions:

Injected Volume = 0.00012 PV

9

may limit the success of the treatment.”


Dose = 0.002 g/kg

Reasons for Poor Performance (cont.)

• Common mistakesf f– Not fully identifying or understanding site conditions

• Geochemistry, geology, contaminant mass distribution, etc.

Underestimating interaction of oxidants with natural media– Underestimating interaction of oxidants with natural media• Not conducting oxidant demand or oxidant persistence evaluations

– Trying to achieve unrealistic goalsy g g• For example: treatment of NAPL sites to MCLs

– Assuming a single application will do the job– Not delivering enough mass of oxidant

• This does not mean increasing concentration will necessarily do the job!

10 RITS Fall 2010: Is ISCO Right for Your Site?

– Not delivering enough volume of oxidant

Introduction to ISCO

ISCO's Sweet Spot

• ISCO performs well when adequate contact with contaminants occursoccurs

– Hydrogeology• Permeable media• Homogeneous media

– Heterogeneous media meets treatment goals less frequently, costs more, and experiences more frequent reboundexperiences more frequent rebound

– Contaminant characteristics• Dissolved phase and low sorbed mass

– Adequate design• Oxidant volume and mass

11

• Delivery frequency and duration





• ISCO Screening



• Case Studies

• Summary

12

• Summary


ISCO Technology Practices Manual (TPM)

• ESTCP funded development of a TPM including protocols d t l t bl it ifi i i f ISCOand tools to enable site-specific engineering of ISCO

(ER-0623)S C O f G– “In Situ Chemical Oxidation for Groundwater Remediation –

Technology Practices Manual”, will be available at SERDP/ESTCP Web site

• Project focus and overall goalTh l i t bl di t bl t ff ti li ti – The goal is to enable more predictable, cost-effective application at DoD sites by providing knowledge and know-how within an ISCO TPM

13 RITS Fall 2010: Is ISCO Right for Your Site?ISCO Technology Practices Manual

ISCO TPM Foundation and Description

ISCO ISCO TPM Contents

I. ISCO processes and techniquesII P t l f ISCO t TPMTPMII. Protocols for ISCO system

selection, design, and implementation

III. Field applications, case study d t b d l i l database and analysis, lessons learned

IV. FAQ guide

Literature review

Case study Technology

practicesSERDP/

Literature review


practicesSERDP/


analysis practices workshop

ESTCP projects


ESTCP projects

ISCO Literature

• Critical review of the literature relevant to ISCO science and technologytec o ogy

– Extensive search of published literature revealedabout 600 ISCO-relevant publicationsS h li it d t id t– Search limited to common oxidants

• Permanganate• Persulfate• Hydrogen Peroxide• Ozone

S i iti ll h t i d d l ifi d d th th hl B. Petri

– Sources initially characterized and classified and then thoroughly reviewed for key findings

– Literature review forms the basis for part of the Technology Practices Man al

15

Manual

RITS Fall 2010: Is ISCO Right for Your Site?ISCO Technology Practices Manual

ISCO Literature (cont.)Study TypesA – Reaction Chemistry, Water PhaseB – Reaction Chemistry, Soil PhaseC – Transport and ModelingD Technology Coupling

Catalyzed Hydrogen Peroxide (CHP)n = 239

Ozonen = 82

D – Technology CouplingE – Field Case StudiesF – Application Guidance

A32%

E13%

F5%

A36%

E10%

F10%

200

250

of xida

nt Permanganate

CHP

B28%

C6%

D16%

B6%

C21%

D17%

100

150

ativ

e N

umbe

r St

udie

s by

Ox CHP

Persulfate

Ozone

8% 6%

A26%E

F9%D

2%

E2%

F11%

Persulfaten = 44

Permanganaten = 207

0

50

1988 1990 1992 1994 1996 1998 2000 2002 2004 2006

Cum

ulLi

tera

ture

26%

C

E23%

B25%

2%

C0%

Year ISCO Literature Published


B15%

C18%D

9%

A60%

ISCO Case Studies

• Critical analysis of ISCO case studies f SCO f– Design of the ISCO database, obtain and extract project information,

populate database and analyze information– ISCO database includes 242 ISCO projects (42 states, 7 nations)p j ( , )

• Federal sites (46)• Manufacturing/Industrial facilities (45)• Dry cleaners (45)• Service stations (25)• Former manufactured gas plants (11)• Former manufactured gas plants (11)• Others

– Database available as “DISCO”

17

• ISCO design vs. site conditions vs. cost and performance…

RITS Fall 2010: Is ISCO Right for Your Site?ISCO Technology Practices Manual

F. Krembs

ISCO Case Studies (cont.)

Oxidants used vs. timen = 182

ISCO applications to different site conditionsn = 149

A34

E9

F8

70

80

90

ts b

y O

xida

nt

PermanganateCHPPersulfateOzone

B3

D21

30

40

50

60

ber o

f Pro

ject Ozone

PercarbonatePeroxone

C740

10

20

1995 1997 1999 2001 2003 2005 2007mul

ativ

e N

um

A - Permeable and Homogeneous; B - Impermeable and HomogeneousC - Permeable and Heterogeneous; D - Impermeable and Heterogeneous

E - Fractured Rock w/low matrix porosity; F - Fractured Rock w/high matrix porosityPermeable K>10-5cm/s = 0 028ft/d

Cum Year ISCO Project Completed


Permeable K>10-5cm/s = 0.028ft/dHomogeneous Kmax/Kmin < 1,000 (modified from NRC 2004)

Workshop of ISCO Professionals

• Technology practices workshop convened at Colorado School of Minesconvened at Colorado School of Mines

– 2-day workshop included 43 participants representing chemical companies, In Situ Chemical Oxidation for

R di ti f C t i t drepresenting chemical companies, technology vendors, environmental consultants, academics, RPMs

P t ti l i d b k t

Remediation of ContaminatedGround Water

Summary Proceedingsof an

ISCO Technology Practices Workshop

• Presentations, panel sessions, and breakout sessions

• Exercise where 6 scenarios were used to obtain

Convened at the

Colorado School of MinesGolden, Colorado

March 7-8, 2007

views regarding ISCO design and performance

• A proceedings document has been published


Source: Siegrist et al. 2008

ISCO TPM Foundation and Description

ISCO ISCO TPM Contents

I. ISCO processes and techniquesII P t l f ISCO t TPMTPMII. Protocols for ISCO system

selection, design, and implementation

III. Field applications, case study d t b d l i l database and analysis, lessons learned

IV. FAQ guide

Literature review


practicesSERDP/

Literature review


practicesSERDP/



ESTCP projects


ESTCP projects

Introduction to ISCO Protocol

• ComponentsTraditional Cleanup Process Systematic Design of ISCO

Preliminary Assessment

– Screening ISCO as an Option for a Site

Site Inspection

Remedial Investigation ISCO Screening

– ISCO Conceptual Design

– Detailed Design and Pl i

Remedial Design ISCO Detailed Design d Pl i

ISCO Conceptual Design

Record of Decision

Feasibility Study

Planning

– Implementation and Performance Monitoring

Remedy in Place

g

Remedial Action Construction

and Planning

ISCO I l t tiPerformance Monitoring Remedial Action Operations

Monitoring and Performance Assessment

Implementation and Performance

Monitoring


Monitored Natural Attenuation and/or Long-Term Monitoring

Response Complete




• ISCO Screening



• Case Studies

• Summary

22

• Summary


How does ISCO work?

• Electron transfer

– Simpler chemistry, more predictable, less powerfulOxidant + Contaminant → Innocuous Byproducts

• Free radical oxidationOxidant + Activator → Radicals

– More complex chemistry less predictable more powerful

Oxidant + Activator → Radicals Radicals + Contaminant → Innocuous Byproducts

More complex chemistry, less predictable, more powerful

Matching the oxidant and delivery system to the CONTACT CONTACT CONTACT!

23 RITS Fall 2010: Is ISCO Right for Your Site?ISCO Screening

g y ycontaminants of concern and site conditions is

critical to achieving performance goals

What goals can ISCO achieve?

• Large concentration reductions (e.g., 90-99%+) are achievable

• Significant risk reduction and mass flux reduction goals are achievable

Frequency of Goals • Ability to meet goals

depends onContaminant mass

Goal% Meeting

Goaln = 122

q ySET for Sites

Evaluate Effectiveness/Optimize

– Contaminant massand distribution

– Hydrogeology

n 122

MCLs 21%

ACLs 44%

R d b X% 33%

MCLsReduceMass/TTC

– Proper designReduce by X% 33%

Reduce Mass/TTC 82%

Eval. Effectiveness/Optimize 100%

ACLs

TTC


OptimizeReduce by X%

When does ISCO work best?

• Hydrogeology– Permeable media with range of distribution approaches; lower

heterogeneity

• Contaminant characteristics– Dissolved phase and low sorbed mass

When appropriate delivery and

contact occur!p

• Proper designCorrect reagent at adequate mass and– Correct reagent at adequate mass andvolume

– Adequate number and frequency of


– Adequate number and frequency ofdelivery events

ISCO Screening

What conditions are challenging for ISCO?

• Significant NAPL mass – Particularly trapped in fractured rock

• HOWEVER reduction of mass flux is feasible

– Particularly when present as highly saturated pools• HOWEVER ISCO is a viable polishing step following source removal

• Treatment to MCLs in source areas

• Large diffuse plumes• Large, diffuse plumes

• Presence of natural materials that arehi hl ti ith id t


highly reactive with oxidants

ISCO Screening

Is pre- or post-ISCO treatment beneficial?

• Pre-ISCO mass recovery or Post-ISCO polishing↑ b bilit f ti l ↓ t ↓ ti↑ probability of meeting goals; ↓ costs; ↓ time

• Examples from case histories– Pre-ISCO excavation, pump & treat, and soil-vapor extraction are

most common (in that order)

– Post-ISCO enhanced bio and Monitored Natural Attenuation (MNA) are most common

• MNA used post-ISCO at 19% of sites in database, likely an underestimate

– Post-ISCO coupling more common at DNAPL sites


What ISCO chemistry options are out there?

• Permanganate• Catalyzed hydrogen peroxide (CHP or Modified Fenton’s reagent)• Catalyzed hydrogen peroxide (CHP, or Modified Fenton’s reagent)

– Natural iron– Chelated-iron (wide range of chelating agents)( g g g )– Iron + low pH

• Persulfate/Activated Persulfate– Alkaline pH (i.e., base)– Chelated-iron– Hydrogen peroxide (H O )– Hydrogen peroxide (H2O2 )– Heat

• Ozone

28

• Others (e.g., Peroxone, Percarbonate)RITS Fall 2010: Is ISCO Right for Your Site?ISCO Screening

What ISCO delivery options are out there?

• Most common Delivery Method (n=148) Count Percent

– Vertical well injection

– Direct push probe

y ( )

Injection Wells 53 35.8

Direct Push 35 23.6

• OthersOften due to CONTACT

Sparge Points 24 16.2

Infiltration 17 11.5

Injectors 11 7 4– Often due to CONTACTlimitations

Injectors 11 7.4

Recirculation 9 6.1

Fracturing 8 5.4g

Mechanical Mixing 3 2.0

Horizontal Wells 2 1.4


How do I choose the best option?

• Understand site conditions!– Ability to degrade COCs

– Deliverability with respect to site-specific hydrogeology and geochemistry

A i l f i – Appropriate treatment goals for site conditions

There is no one oxidant and/or delivery approach that works

for all contaminant, hydrogeology & geochemical


hydrogeology, & geochemical conditions!

ISCO Screening: Lessons Learned

• Successful ISCO depends on:– Understanding site conditions

• Basic geology, geochemistry, contaminant mass and its distribution

– Selecting the correct oxidant for the site contaminants and geochemical conditions

Selecting the correct delivery approach for the oxidant and site – Selecting the correct delivery approach for the oxidant and site hydrogeological conditions

– Appropriate treatment goals for site conditionspp p g• Understanding ISCO’s ability to meet these goals

– Coupling ISCO with other pre- or post-ISCO conditions appropriately

31

– Appropriate design: mass, volume, frequency, duration

RITS Fall 2010: Is ISCO Right for Your Site?ISCO Conceptual Design

ISCO Screening ProcessSTART:

1. ISCO Screening

Data Collection: Characterization data, COCs, risk pathways,

PRGs/RAOs preliminary target 1Is ISCO applicable to site COCs and A

No

Is the CSMadequately defined

for screening

PRGs/RAOs, preliminary target treatment zones

1conditions?

STOP:Evaluate other technologies

No

Yes

B

purposes?

ISCO Screening Process:Determine viable ISCO options

Consider pre-ISCO technologies/processes 2 C

Are pre-ISCO processes previously implemented,

required or already

Yes

Yes

technologies/processes

Detailed ISCO Screening 3

required or already occurring?

No

Determine if value is added by couplinga pre- or post-ISCO process

4

Are viable ISCO ti il bl ?

DSTOP: Evaluate other technologies or review

No viable options

options available?

Is data support adequate? E

technologies or review site approach

No

Viable options exist


Proceed to conceptual design with a limited number (e.g., 1–3) of higher scoring options

for ISCO and/or coupled approaches

Yes

Data CollectionSTART:

1. ISCO Screening



No

• Data– Conceptual Site Model (CSM)


for screening


1conditions?


No

Yes

BConceptual Site Model (CSM)• Contaminant • Hydrogeology

purposes?




required or already

Yes

Yes

• Geochemistry• Goals and objectives• Site plan




No

• Site plan

– ISCO-specific • Collect soil and groundwater to


4



No viable optionsg

store if ISCO is even a remote possibility

–For oxidant demand/persistence d t t bilit l ti

options available?



No


33

and treatability evaluations

RITS Fall 2010: Is ISCO Right for Your Site?ISCO Screening



Yes

Basic ScreeningSTART:

1. ISCO Screening



No


for screening


1conditions?


No

Yes

B

purposes?




required or already

Yes

YesCategory 1

Contaminant classes highly amenable to effective

degradation by commonly

Category 2Contaminant classes

degradable by common ISCO oxidants but effectiveness is

Category 3Contaminant classes not

amenable to ISCO treatmenttechnologies/processes



No

degradation by commonly used ISCO oxidants

oxidants but effectiveness is less certain

Chloroethenes Chloroethanes Heavy metalsBTEX Chlorinated/brominated methanes Radionuclides


4



No viable options

TPH Explosives (RDX, TNT, etc.) Inorganic saltsPAHs Organic herbicides or pesticides Perchlorate

Chlorobenzenes NDMA Nutrients (nitrate, ammonia, h h t )options available?



No


phosphate)Phenols (e.g., chlorophenols) Ketones

Fuel oxygenates (MTBE, TAME) PCBsAlcohols Dioxins/Furans




Yes1,4-dioxane

Basic Screening (cont.)START:

1. ISCO Screening



No


for screening


1conditions?


No

Yes

BLow Contaminant Concentration/MassConcentration purposes?




required or already

Yes

YesType of ISCO Treatment Goal:

Concentration Reduction Mass Reduction Mass Flux Reduction

Removal magnitude (%) 50-90 90-99 99-99.9 50-90 90-99 99-99.9 50-90 90-99 99-99.9Unconsolidated mediaHomogeneous permeable 1 1 2 1 1 2 1 1 2Heterogeneous permeable 1 2 2 1 1 2 1 1 2




No

Homogeneous low permeability 1 2 2 1 1 2 1 1 2Heterogeneous low permeability 1 2 2 1 1 2 1 1 2Consolidated media (fractured)Sedimentary 1 2 2 1 1 2 1 1 2Igneous/metamorphic 1 2 3 1 2 3 1 1 2Karst 1 2 3 2 2 3 1 2 3


4



No viable options

Karst 1 2 3 2 2 3 1 2 3High Contaminant Concentration/Mass

Type of ISCO Treatment Goal:Concentration

Reduction Mass Reduction Mass Flux ReductionRemoval magnitude (%) 50-90 90-99 99-99.9 50-90 90-99 99-99.9 50-90 90-99 99-99.9

Unconsolidated mediaoptions available?



No


Homogeneous permeable 1 1 2 1 1 2 1 1 2Heterogeneous permeable 1 2 3 1 1 2 1 2 3Homogeneous low permeability 1 2 3 1 2 3 1 2 3Heterogeneous low permeability 1 2 3 1 2 3 1 2 3

Consolidated media (fractured)Sedimentary 1 2 3 1 2 3 1 1 2




YesSedimentary 1 2 3 1 2 3 1 1 2Igneous/metamorphic 2 2 3 2 3 3 1 2 3Karst 2 3 3 3 3 3 2 3 3

Basic Screening(cont.)

Low Contaminant Concentration/MassType of ISCO Treatment Goal: Concentration Reduction Mass Reduction Mass Flux Reduction

Removal magnitude (%) 50-90 90-99 99-99.9 50-90 90-99 99-99.9 50-90 90-99 99-99.9Unconsolidated mediaHomogeneous permeable 1 1 2 1 1 2 1 1 2H t bl 1 2 2 1 1 2 1 1 2(cont.) Heterogeneous permeable 1 2 2 1 1 2 1 1 2Homogeneous low permeability 1 2 2 1 1 2 1 1 2Heterogeneous low permeability 1 2 2 1 1 2 1 1 2Consolidated media (fractured)Sedimentary 1 2 2 1 1 2 1 1 2Igneous/metamorphic 1 2 3 1 2 3 1 1 2Karst 1 2 3 2 2 3 1 2 3

High Contaminant Concentration/Mass

Type of ISCO Treatment Goal: Concentration Reduction Mass Reduction Mass Flux ReductionRemoval magnitude (%) 50-90 90-99 99-99.9 50-90 90-99 99-99.9 50-90 90-99 99-99.9

Unconsolidated mediaHomogeneous permeable 1 1 2 1 1 2 1 1 2

Heterogeneous permeable 1 2 3 1 1 2 1 2 3Homogeneous low permeability 1 2 3 1 2 3 1 2 3Heterogeneous low permeability 1 2 3 1 2 3 1 2 3Heterogeneous low permeability 1 2 3 1 2 3 1 2 3

Consolidated media (fractured)Sedimentary 1 2 3 1 2 3 1 1 2Igneous/metamorphic 2 2 3 2 3 3 1 2 3Karst 2 3 3 3 3 3 2 3 3

High Contaminant Concentration/Mass

Type of ISCO Treatment Goal:Concentration

Reduction Mass Reduction Mass Flux ReductionRemoval magnitude (%) 50-90 90-99 99-99 9 50-90 90-99 99-99 9 50-90 90-99 99-99 9Removal magnitude (%) 50-90 90-99 99-99.9 50-90 90-99 99-99.9 50-90 90-99 99-99.9

Unconsolidated mediaHomogeneous permeable 1 1 2 1 1 2 1 1 2Heterogeneous permeable 1 2 3 1 1 2 1 2 3Homogeneous low permeability 1 2 3 1 2 3 1 2 3


Homogeneous low permeability 1 2 3 1 2 3 1 2 3Heterogeneous low permeability 1 2 3 1 2 3 1 2 3

START:1. ISCO Screening



NoPre-ISCO Processes


for screening


1conditions?


No

Yes

B

purposes?




required or already

Yes

Yes

Pre-ISCO Advantages Disadvantagestechnologies/processes



No

Technology Advantages Disadvantages

Excavation • Rapid implementation• Easy to apply oxidant at

the infiltrative surface

• Hotspots may remain• Preferential flow may occur

through backfillDetermine if value is added by coupling

a pre- or post-ISCO process4



No viable options

the infiltrative surface• Soil mixing approaches

may be more easily implemented

through backfill• Contaminated or highly

organic backfill may cause excessive oxidant demandOxidant treatment of clean options available?



No


• Oxidant treatment of clean backfill represents inefficient oxidant use




Yes

ISCO Screening

START:1. ISCO Screening



No

Screening Tool for Si S ifi


for screening


1conditions?


No

Yes

B

Site-Specific Conditions

purposes?




required or already

Yes

Yes




No


4



No viable options

options available?



No





Yes

Screening Tool for Site-Specific Conditions (cont.)

• Site factorsBasic geology– Basic geology

– Contaminants and co-contaminants– Geochemistry (e.g., pH, alkalinity, chloride, organic carbon content)Geochemistry (e.g., pH, alkalinity, chloride, organic carbon content)– Aquifer hydrology parameters (e.g., permeability and heterogeneity)

• Lookup categoriesp g– Appropriate oxidant and activation approaches for

contaminant(s)A i t id t d ti ti h f

Options

– Appropriate oxidant and activation approaches for geochemistry

– Appropriate delivery approach for viable oxidants

39

– Appropriate delivery approach for geology


Screening Tool for Site-Specific Conditions (cont.)

• Outputf f f– Narrower range of viable options for the site based on site-specific

factors– These are the options that can be carried to the Conceptual Design p p g

phase

• NOTE– There is room for practitioner experience and expertise in the process!– Other key considerations in selecting the oxidant and delivery

approachapproach–Issues of implementability

• Are there operations/activities or structures that cannot be disrupted?

40

• Are there subsurface utilities that must be considered?





• ISCO Screening



• Case Studies

• Summary

41

• Summary


How many injection points?

• Function of– Oxidant characteristics – reaction and/or decomposition

– Oxidant depletion/decomposition rate

– Delivery duration and rate

– Delivery volumeTO WHAT EXTENT ARETHESE VALUES WELLUNDERSTOOD WHENDelivery volume

– Porosity

Contaminant mass and mass distribution

UNDERSTOOD WHENINITIATING ISCO DESIGN?

– Contaminant mass and mass distribution

42 RITS Fall 2010: Is ISCO Right for Your Site?ISCO Conceptual Design

How many injection events?

• Typical number of injections is 2-3– Average number of injection events in case study database is ~3

– Survey of professionals: 78% said 2 or more injection rounds was their average experience of ISCO for dissolved plumes in sandy media (Cooper et al., 2006)

• Will not know exact number of events before project start

• Observational approach is critical component of executionpp p– Forms basis for decision based on site-specific experiences


What volume of oxidant?

• More successful sites tend to have longer injection duration per injection event AND greater total volume of oxidant deliveredinjection event AND greater total volume of oxidant delivered

• Review of case histories– PCE sites with >90% reduction = 0.51 PV

– PCE sites with <90% reduction = 0.24 PV

– TCE sites with >90% reduction = 0.49 PV

– TCE sites with <90% reduction = 0.24 PV

• Survey of professionals– 10-30% of PV is average injected volume specified in design

44

g j p g(Cooper et al., 2006)


What are treatability and pilot tests?

• Treatability tests are:– Laboratory-scale ISCO simulations

– Also called “bench tests”

– Batch reactors or flow-through columns/tanks

– Used to evaluate ISCO chemistry issues (additional details to follow)Used to evaluate ISCO chemistry issues (additional details to follow)

• Pilot tests are:– Initial ISCO application performed at field site

– Generally smaller scale than anticipated full scale application


– Used to evaluate oxidant delivery issues (additional details to follow)


Why perform lab treatability tests?

• Improve understanding of system chemistry– Contaminant destruction extent and rate under idealized

conditions

– Oxidant depletion extent and rate

– NAPL destruction

– Byproducts/intermediates and other geochemical impacts(e.g., metals mobilization)

• Optimize reaction chemistry– Oxidant dose and/or activation approach

Basic oxidant demand test and contaminant treatability test: typically under $10-20KDuration: 1 week to 2 monthsMore complexity = greater cost and longer duration


O da t dose a d/o act at o app oac


p y g g• Byproducts/intermediates analysis, transport evaluations, complex contaminant mixtures,

extensive number of reaction conditions

Why perform lab treatability tests? (cont.)

• Will the oxidant sterilize the soil and prevent future i bi l d d ti f t i t ?microbial degradation of contaminants?

C ISCO b d t i hibit h bi ?NO!

• Can ISCO byproducts inhibit or enhance bioprocesses?

Does ISCO mobilize metals?BOTH!

• Does ISCO mobilize metals?

• What other effects does ISCO have?Be aware of and prepare for possibility

• What other effects does ISCO have?pH, solids, gas, temperature, DO, specific conductanceTHESE ARE GREAT MARKERS OF DELIVERY…


Why perform field pilot-scale tests?

• To assessAbilit f f ti t t l f id t d/ t f d li– Ability of formation to accept volume of oxidant and/or rate of delivery

– Impact of heterogeneities on oxidant distribution– Radius or zone of influence of oxidant– Radius or zone of influence of oxidant– Design uncertainty– Treatment effectiveness– Rebound potential– BONUS: initial contaminant mass destruction

• Example from case histories– In heterogeneous media with DNAPL, the percentage reduction of

48

chlorinated VOCs was greater at full-scale sites that performed pilot tests


What does ISCO cost?

• What are typical or expected costs?$ / 3 ( )– Median: $94/yd3 (n=33)

– Median total project cost: $220,000 (n=55)

f ?• What are the primary determinants of cost?– COC group

C t i t l bilit d h d h bi it M di b f d li• Contaminant solubility and hydrophobicity• Amenability to biodegradation

– Geology

Median number of delivery events = 2 (n=27)

Median duration of delivery events = 8 days (n=19)Geology

• Permeability and heterogeneity

– Contaminant mass density

events = 8 days (n=19)Median PVs = 0.2 (n=21)

(above includes only sites with unit cost data, and omits ozone projects,

49

• DNAPL treated at higher cost


p jwhich typically last longer but are

automated systems)

What does ISCO cost relative to other technologies?

• McDade et al., 2005 study found median costs of treatment at DNAPL source zones of:sou ce o es o

– Bioremediation $29/yd3

– Thermal $88/yd3

– ISCO $125/yd3

– Surfactant/Cosolvent Flushing $385/yd3

• Industry thinking is that total costs are: Bioremediation < ISCO < Thermal

• Industry thinking is that total time required to achieve treatment is:

Th l < ISCO < Bi di ti

50

Thermal < ISCO < Bioremediation


What do ISCO reagents cost relative to other options?

• Approximate ISCO Reagent Costs– Permanganate $2/lb

– Persulfate $2/lb

– Hydrogen Peroxide $0.5/lb (50% to 67% water)

– Ozone costs depend on generatorOzone costs depend on generator

• Approximate Bioremediation Reagent Costs– Molasses $0.4/lb

– Sodium Lactate $1/lb


– Emulsified Oils $1 to $2/lb (~50% water)


ISCO Conceptual Design: Lessons Learned

• Successful ISCO depends on:Understanding interaction of oxidants with natural media– Understanding interaction of oxidants with natural media

• Relationship of rate of oxidant depletion to rate of oxidant delivery

– Applying the appropriate mass, concentration, and volumepp y g pp p , ,• Increasing delivery volume has been associated with success

– Planning for multiple delivery events– Understanding design uncertainty

• If focused on chemistry/geochemistry, reduce uncertainty with lab tests• If focused on issues of deliverability, reduce uncertainty with pilot testsIf focused on issues of deliverability, reduce uncertainty with pilot tests

– Understanding cost variables and appropriately reducing cost uncertainty

• Costs are minimized through solid design and real time decision making

52

• Costs are minimized through solid design and real-time decision making


Ti 1 C t l

START:2. Conceptual Design

Select Target Treatment Zone (TTZ) 1

Tier 1 ConceptualDesign: CompareISCO alternatives (e.g., 1-3 options from screening)

Select design tool input parameters 2

Mass balance and experience

3a Spreadsheet design tool

3b

STOP:Reconsider treatmentISCO Conceptual

Is at least one technologically and

economically feasible option

available?

A

Reconsider treatment objectives, TTZ, CSM

certainty, ISCO assessment tool input

and outcome (screening process), and coupling

approaches

No

Yes

ISCO Conceptual Design Process

Tier 2 Conceptual Design: Iteratedesign tool to refine design

Is cost and performance B

Rank and select oxidantand delivery approach options based on certainty of delivery and effectiveness, and cost

4

Yesrefine design. p

confidence acceptable?

B

Consider additional data needs 5STOP:

If fatal design

No

Consider additional modeling needs 6

Refine design with new information 7

Perform FS cost estimation 8

If fatal design flaw is identified

during data collection

and/or modeling efforts


Proceed with remediation alternatives comparison or

detailed design and planning

Ti 1 C t l



Tier 1 Conceptual





3b

STOP:Reconsider treatmentTier 1 Conceptual

Design: Design ToolIs at least one

technologically and economically

feasible option available?

A




approaches

No

Yes

Tier 2 Conceptual Design: Iteratedesign tool to refine design



4

Yesrefine design. p

confidence acceptable?

B


If fatal design

No










Example: Radial Flow

Radial Flow 1-D Column Flow Radial Flow & Drift

Choose your Flow Type

p

Tier 1 Conceptual Design Tool

Value Units

61 days1 day30 ft5 days

50 mg/L

Model Set Up (see "Model Description" worksheet)

Minimum Oxidant Concentration to Calc ROI

Modeling DurationTime Step

Model LengthTarget Number of Days to Calc ROI

• Soil and oxidant demand characteristics

Design Tool g

30 ft bgs40.00 ft bgs

10 ft5.0000 ft0.30 L/L

Hydrogeologic Characteristics

Thickness of Mobile Zone (Z)

Top of Injection Interval

Porosity

Bottom of Injection IntervalAquifer Thickness

• Injection design parameters– Concentration

Duration

3.0000 ft10.00 ft/day

15 ft

1.60 Kg/L3.0 g MnO4/Kg

Bulk Density

Longitudinal Dispersivity

Total NOD

Soil and NOD Characteristics

Depth to Water TableHydraulic Conductivity (k)

– Duration– Rate

• Desired outcomes

0.500.0030 L/mmol - d

Potassium Permanganate158.03 g/mol0.00 mg/L

Fraction Instantaneous

Oxidants Information

Name of Oxidant

Initial Oxidant Concentration

2nd Order Slow NOD Consumption Rate (K2S)

Molecular Weight of Oxidant

– Concentration at radius of influence (ROI) perimeter

– Duration for oxidant to Borden et al., 2009

TCE131.40 g/mol1.00 mg/L

Contaminants Information

Name of Contaminant

Initial Contaminant ConcentrationMolecular Weight of Contaminants

Period 1

Injection Condition


remain at that point


,Duration 4 DaysContaminant Conc. 0.004 mMol/LMnO4 Conc. 35.23 mMol/LInjection Rate 68,137.41 L/Day

Tier 1 Conceptual Design Tool (cont.)

Oxidant Concentration vs. Radial Distance

7000

8000

(mg/

L)

3 days

5 days

33 days

4000

5000

6000

7000

ncen

tratio

n 61 days

Target Oxidant Conc.

1000

2000

3000

4000

Oxi

dant

Con

00 5 10 15 20 25 30 35

Radial Distance (ft)

O

50 mg/L


Tier 1 Conceptual Design Tool: Examples

• Base case60 day model duration; minimum oxidant concentration to achieve = 50 mg/L– 60 day model duration; minimum oxidant concentration to achieve = 50 mg/L

– Treatment area = 50’ x 75’– Injecting into 10’ thickness at 30-40’ depth interval WELL DELIVERY

• 5 foot mobile zone within the 10 foot thickness– Longitudinal dispersivity = 3 ft– Hydraulic conductivity = 10 ft/day

• 2” well • 25 psi inj. pressure• 10 hours/day

= 6 000 gpd/well– Hydraulic conductivity = 10 ft/day – Natural oxidant demand = 1 g MnO4

-/kg porous media• Fraction instantaneous = 0.5

= 6,000 gpd/well

• 2nd order rate for slower fraction = 0.003 L/mmol-d– Radius of influence (ROI) overlap desired = 20%– Five days of injection (2 injection events)


Five days of injection (2 injection events)– 5,000 mg/L oxidant concentration


Tier 1 Conceptual Design Tool: Examples (cont.)


8000

mg/

L)

3 days

5 days

33 days

3000

4000

5000

6000

7000

Con

cent

ratio

n (

61 days


Base Case (NOD = 1 g/kg)• ROI = 28 ft

0

1000

2000

3000

0 5 10 15 20 25 30 35

Oxi

dant

• wells needed = 2• Cost = $68,500

Oxidant Concentration vs. Radial Distance 3 daysRadial Distance (ft)

5000

6000

7000

8000

ntra

tion

(mg/

L) 5 days

33 days

61 days


NOD = 3 g/kg• ROI = 18 ft• wells needed = 5• Cost = $112,0001000

2000

3000

4000

Oxi

dant

Con

ce


00 5 10 15 20 25 30 35




8000

mg/

L)

3 days

5 days

33 days

Base Case (5 days injection)• ROI = 28 ft3000

4000

5000

6000

7000

Con

cent

ratio

n (

61 days



0

1000

2000

3000

0 5 10 15 20 25 30 35

Oxi

dant


5000

6000

7000

8000

ntra

tion

(mg/

L) 5 days

33 days

61 days


1 day injection• ROI = 12 ft• wells needed = 11• Cost = $88,0001000

2000

3000

4000

Oxi

dant

Con

ce


00 5 10 15 20 25 30 35




8000

mg/

L)

3 days

5 days

33 days

Base Case (5,000 mg/L MnO4-)

• ROI = 28 ft3000

4000

5000

6000

7000

Con

cent

ratio

n (

61 days



0

1000

2000

3000

0 5 10 15 20 25 30 35

Oxi

dant


5000

6000

7000

8000

ntra

tion

(mg/

L) 5 days

33 days

61 days


7,500 mg/L MnO4-

• ROI = 30 ft• wells needed = 2• Cost = $74,5001000

2000

3000

4000

Oxi

dant

Con

ce


00 5 10 15 20 25 30 35




8000

mg/

L)

3 days

5 days

33 days

Base Case (5,000 mg/L MnO4-)

• ROI = 28 ft3000

4000

5000

6000

7000

Con

cent

ratio

n (

61 days



0

1000

2000

3000

0 5 10 15 20 25 30 35

Oxi

dant


5000

6000

7000

8000

ntra

tion

(mg/

L) 5 days

33 days

61 days


2,500 mg/L MnO4-

• ROI = 21 ft• wells needed = 3• Cost = $73,7001000

2000

3000

4000

Oxi

dant

Con

ce


00 5 10 15 20 25 30 35


Tier 2 Conceptual DesignTi 1 C t l



• Tools available





3b

STOP:Reconsider treatment

– Treatability test procedures• Oxidant demand

Is at least one technologically and

economically feasible option

available?

A




approaches

No

Yes

– Pilot test procedures

• Sophisticated modelingTier 2 Conceptual Design: Iteratedesign tool to refine design



4

YesSophisticated modelingtools

• Refined cost estimation

refine design. pconfidence acceptable?

B


If fatal design

No

• Refined cost estimationtools













• ISCO Screening



• Case Studies

• Summary

63

• Summary


Are there regulatory issues for ISCO?

• Similar for all oxidantsR l t P

• Secondary containment• Regulatory Programs

– RCRA Hazardous Waste RSD forex-situ systems

• Occupational Safety and Health Administration (OSHA)

f f– CERCLA “release” or “process” definition

– EPCRA reporting

• Potential for exacerbation of indoor air exposure

Impacts to secondary water • State approval for materials

(variances have been granted)

• Impacts to secondary water quality standards

– Taste and odor• Underground injection control

(UIC)• Homeland Security Top Screen

• Manganese, sulfate, etc.

• Metals residuals after ISCO


• Homeland Security Top-Screen

ISCO Detailed Design, Implementation, and Monitoring

What are the important safety precautions?

• Careful health and safety planning, training, and monitoring is mandatorya dato y

• Common hazards– Chemical potential energyp gy– Exothermic reaction heat and gases– Chemical incompatibility – High pressure– Acids/bases– Electrical– Dust hazards

Leak potentials

65

– Leak potentials

RITS Fall 2010: Is ISCO Right for Your Site?ISCO Detailed Design, Implementation, and Monitoring

What should be monitored?

• Dynamic, adaptive, flexible• Real-time (optimization)

• Two phases

Real time (optimization)• Baseline, routine, closure

• Two phases– Delivery/Operational

Man of the prod cts of ISCO (e g pH gas dissol ed o gen solids etc ) • Many of the products of ISCO (e.g., pH, gas, dissolved oxygen, solids, etc.) are excellent indicators of successful delivery

• Delivery should be confirmed BEFORE treatment monitoring is initiated

– Treatment/Performance• Verification of desired COC treatment


• Can include sampling of groundwater and/or soil phases


How is design optimized real time?

• Triad Approachhttp://meso.spawar.navy.mil/Newsltr/Images/fy92_no1.gif

Marine Environmental Update, Vol FY 92, No. 1

Sequence of steps in the Observational Method

• Observational Method– Integrate performance monitoring

results and decision logic REAL-TIMEScoping

Scoping

Traditional RI/FSObservational Methodand comparison with the RI/FS process.

g• Operation/injection can be adapted

“as you go”– Relies on understanding of and

Determine response action

Establish site conditionsRemedial investigationg

planning for uncertainties• Reasonable bounds of conditions

and response plans

Probable condition and reasonable deviations

Feasibility study

Remedial investigation

Feasibility study, record of decision

• Techniques– Direct push technologies (DPT)

In sit sensors ith data loggers

Design remedial action

Implement remedial action

Design remedial action

Implement remedial action


– In situ sensors with data loggers(e.g., temperature, conductivity)


Respond to deviations Implement contingency plan

Is rebound a problem?

• Rebound defined– Increase in aqueous phase COC concentrations that occur after ISCO

following an initial reduction in concentration that resulted from the ISCO application: NOT influxpp

• CausesContaminant mass remains untreated– Contaminant mass remains untreated

• Post-ISCO equilibration/partitioning

• ATTRIBUTES• ATTRIBUTES– Marking transfer of contaminants to more treatable aqueous phase

C h l l t k NAPL/ b d

68

– Can help locate unknown NAPL/sorbed

RITS Fall 2010: Is ISCO Right for Your Site?ISCO Detailed Design, Implementation, and Monitoring

ISCO Detailed Design, Planning, Implementation and Monitoring: Lessons LearnedMonitoring: Lessons Learned• Successful ISCO depends on:

– Regulatory compliance– Understanding and planning for hazards associated with

handling oxidantshandling oxidants– Real-time, dynamic monitoring

• Delivery and treatment performance considered independently• Delivery and treatment performance considered independently

– Applying the Observational Method or Triad Approach• Real-time decision making and optimization• Real-time decision making and optimization• Contingency planning

– Planning for and exploiting “rebound” or contaminant

69

Planning for and exploiting rebound or contaminantre-equilibration

PreliminaryDesign

START:3. Detailed Design and Planning

Prepare preliminary basis of design report 1

STOP:

Meet and AgreeP i t P di

A

Is the preliminarydesign basis adequate for

detailed design?

Identify operational objectives and prepare ti d ti l

2

STOP:Perform data

collection, modeling, and/or pilot testing to

refine design and reduce uncertainty

Yes

No

ISCO Detailed D i d

Final Design

Prior to Proceeding

B

Is a performance-based contract

feasible and cost-

operation and contingency plan

Prepare performance specifications

3aPrepare detailed

design specs and drawings

3bNo Yes

Design and Planning Process

feasible and costeffective?

Is the project constructible

and biddable?

C

specificationsand drawings

Prepare a constructioncost/ engineer’s

estimate5

Refine preliminary basis of design report,

operation plan, and performance specs/

detailed design specs d d i

7

No

Yes

Is the projected cost

within the budget?

D

Perform value engineering or design optimization assess-

ment to improve constructibility and

biddability

4Perform value

engineering or design optimization

assessment to costs

and drawings

6

No

No

Yes

PlanningMeet and Agree Prior to Proceeding

Assemble procurement packages, conduct bid process,and select contractors

8

Prepare quality assurance, health and safety, and performance monitoring plans

9

70 RITS Fall 2010: Is ISCO Right for Your Site?ISCO Detailed Design, Implementation, and Monitoring

Proceed to implementation and performance monitoring

sa e y,a d pe o a ce o o g p a s

ISCO Detailed Design and Planning Process (cont.)

• Key features– Preliminary design

• Refine conceptual design– Rerun design tools with new data

– Detailed evaluation of logistics of well locations, oxidant delivery, etc.

• Document design in Design Basis Report• Document design in Design Basis Report

• Reassess adequacy of information

• Prepare contingency plans PreliminaryD i

START:3. Detailed Design and Planning

Prepare preliminary basis of design report 1Prepare contingency plans Design

A

Is the preliminarydesign basis adequate for

detailed design?

STOP:Perform data

collection, modeling, and/or pilot testing to

refine design and reduce uncertainty

No


Meet and AgreePrior to Proceeding

Identify operational objectives and prepare operation and contingency plan

2

yYes

ISCO Detailed Design and Planning Process (cont.)

• Key features (cont.) Final Design

Is a performance-b d t t

Prepare Prepare detailed No Yes

– Final design and planning

Bbased contract feasible and cost-

effective?

Is the project constructible

and C

performance specifications

3adesign specs and drawings

3b

Prepare a constructioncost/ engineer’s 5

Refine preliminary basis of design report,

operation plan, and 7

Yes

• Decide on contracting approach

• Evaluate constructability Is the

projected cost within the D

biddable?

Perform value engineering or design optimization assess-

ment to improve4

estimate

Perform value engineering or design

performance specs/ detailed design specs

and drawings

7

6

No

Noyand cost

• Prepare contracting packages and plans

PlanningMeet and Agree

within the budget?

ment to improve constructibility and

biddability

g g goptimization

assessment to costs

Assemble procurement packages, conduct bid process and select contractors

8

6

Yes

packages and plans Prior to Proceeding

Proceed to implementation

bid process, and select contractors

Prepare quality assurance, health and safety, and performance monitoring plans 9


Proceed to implementation and performance monitoring

ImplementationComplete pre-construction activities 1

START:4. ISCO Implementation and Performance Monitoring

Implementation and Performance Monitoring

Do baseline monitoring results confirm CSM and

affirm the path forward?

A

Install ISCO implementation infrastructure and complete baseline monitoring

2

Refine the CSM

3No

Review and modifyoperation and

contingency plan to account for learned site

conditionsMeet and agree

prior to proceeding

4

Performance Monitoring Process• Key features

forward?

Are site conditions significantly

different to require re-design?

BInitiate operation plan, including delivery,

process monitoring, and optimization programs

5No

Yes

Yes

• Key features– Re-assess approach after

baseline data collection

Delivery Performance MonitoringAre delivery monitoring

results meeting process

performance criteria?

C

Are modifications

achieving delivery

performance milestones?

D

Execute delivery

contingency plan

6No No

– Separate and highlight DELIVERY performance monitoring from Are

difi tiAre

treatment

Implement treatment performance monitoring program 7

Execute

STOP:Re-evaluate the ISCO approach

No

Yes

No

Yes

Yes

monitoring from TREATMENT performance monitoringNote contingency

modifications achieving

performance milestones?

Ftreatment

results meeting performance

criteria?

E

Havetreatment

objectives been G

treatment contingency

plan

8No

Yes

No

No


– Note contingency implementation


Treatment Performance Monitoring

STOP: ISCO Treatment Complete

objectives been achieved?

Yes




• ISCO Screening



• Case Studies

• Summary

74

• Summary


Case Study 1 – NTC Orlando OU-4 (2000 to 2003)

• COC ConditionsPCE d d d ti d t i t ti i GW PCE 26 000 – PCE and degradation products, maximum concentrations in GW: PCE 26,000 µg/L, TCE 13,000 µg/L, 3,900 µg/L cis-DCE, DNAPL assumed to be present

• Geologic Conditions– Fine to medium sand, average hydraulic conductivity (K) = 30 ft/day

• Project Goals– Attain Florida MCLs of 3 µg/L PCE and TCE, 70 µg/L cis-DCE in groundwater– Up to 99.99% concentration reduction required

• ISCO Full Scale Design– Permanganate recirculation

5 i t NOD b h t t il t d MODFLOW


– 5-minute NOD bench test, pilot, and MODFLOW

Case Study 1

Photo courtesy of M. Singletary, NAVFAC SE

Project Results

• Injection and extraction rates declined significantly over time Attributed to solid manganese dioxide (MnO ) precipitation– Attributed to solid manganese dioxide (MnO2) precipitation

– Well rehabilitation and alternative filtration efforts unsuccessful– Resulted in fewer than expected PVs recirculatedResulted in fewer than expected PVs recirculated– Outcome significantly different than that predicted by MODFLOW

• Project goals not achieved, and COCs persisted at j g , pconcentrations above MCLs

• Bioremediation with emulsified oil used in source area after ISCOISCO

• Subsequent 5-day NOD testing indicated high NOD (0.5 to 7 mg/kg) and reactive transport modeling indicated short to very

76

mg/kg) and reactive transport modeling indicated short to very short permanganate transport distances

RITS Fall 2010: Is ISCO Right for Your Site?Case Study 1 – NTC Orlando OU-4

Key Lessons Learned

• Results highlight the importance of NOD– Significant amount of oxidant consumed due to non-target

reactions

• Traditional groundwater models (e g MODFLOW) may not • Traditional groundwater models (e.g., MODFLOW) may not predict ISCO result

– Groundwater flow ≠ Oxidant flowGroundwater flow ≠ Oxidant flowbecause oxidant reacts during transport

– ISCO can change aquifer hydraulicpropertiesproperties

• Project goals were very aggressive, and unrealistic in most situations


and unrealistic in most situations

Case Study 1 – NTC Orlando OU-4

Photos courtesy of M. Singletary, NAVFAC SE

Case Study 2 – NAS South Weymouth Bldg. 81 (2000)

• COC ConditionsC i l d PCE d BTEX f UST d l t i – Commingled PCE and BTEX from UST and solvent use, maximum concentrations in GW: PCE 1,000 µg/L, 850 µg/L BTEX, DNAPL likely present

• Geologic Conditions– Fractured granite bedrock, average K = 0.4 ft/day– Fractures spacing generally less than 1 ft, though borehole geophysics

indicate that hydraulically significant fractures are more widely spacedindicate that hydraulically significant fractures are more widely spaced

• Project Goals– Reduce COC concentrations in GW by 90%Reduce COC concentrations in GW by 90%

• ISCO Pilot Design– 2 events of CHP into vertical wells, 1 PV of 50% H2O2 mixed with iron catalyst


2 events of CHP into vertical wells, 1 PV of 50% H2O2 mixed with iron catalyst

Case Study 2

Project Results

• Significant COC reductions observed in GW, followed by rebound rebound

– 90% reductions only achieved for short timeR b d d ithi i t l 2 th f i j ti– Rebound occurred within approximately 2 months of injection

– Rebound occurred in only one third of monitoring wells

• Project goals not achieved as COC reductions were not permanent

• Monitoring data indicated that oxidant solution may have flowed preferentially through larger fractures

79

• Another source zone remedy to be selected in 2011RITS Fall 2010: Is ISCO Right for Your Site?Case Study 2 – NAS South Weymouth Building 81

Key Lessons Learned

• ISCO can be performed in fractured rock, but significant challenges existchallenges exist

– Preferential flow through fractures– Diffusion of COCs out of rock matrix (“back-diffusion”) leading to Diffusion of COCs out of rock matrix ( back diffusion ) leading to

rebound– Very difficult to assess mass of COCs in non-aqueous phases, so mass

reduction calculations also very difficultreduction calculations also very difficult

• Rebound was limited to small portion (~33%) of treatment zoneSi il b ti t th ISCO f t d k li ti i – Similar observations at other ISCO fractured rock applications in DISCO

– May suggest that ISCO rebound data can help refine location of

80

y gg psubsurface hot spots

RITS Fall 2010: Is ISCO Right for Your Site?Case Study 2 – NAS South Weymouth Building 81

Case Study 3 – Allegheny Ballistics Lab., WV (2005)

• COC Conditions1 000 lbs TCE disposed of each month in unlined pits from 1970 to 1978 – 1,000 lbs TCE disposed of each month in unlined pits from 1970 to 1978 (96,00 lbs total?), GW concentrations up to 50,000 µg/L, DNAPL presence very likely

G l i C diti• Geologic Conditions– Heterogeneous sand and gravel alluvial deposits

Project goals • Project goals – Evaluation of ISCO as potential mass reduction technology

• ISCO Pilot Design• ISCO Pilot Design– Persulfate injected into vertical wells, activated by iron first, followed

by heat


– 0.4 g/kg oxidant dose, 0.007 PVs

Case Study 3

Project Results

• Modest reductions observed 3 weeks post-ISCOSi ifi t b d f 6 k t ISCO d i • Significant rebound from 6 weeks post-ISCO onwards, in some cases to concentrations equal to or greater than pre-ISCO concentrations

• No soil sampling performed, groundwater concentrations didn’t decline, how to assess mass reduction?

“ it h b f l t l t l ffi i b i – “…it may have been useful to evaluate removal efficiency by measuring concentrations of COCs in both soil and groundwater… it is possible that removal efficiency achieved by pilot test was underreported based solely on analytical results of groundwater samples.” (NAVFAC 2010)y y g p ( )

– Mass reductions generally greater, sometimes significantly greater, in soil phase relative to groundwater phase based on sites in DISCO

T t l t $407 000 $58/ d3 (NAVFAC 2010)


• Total cost $407,000, or $58/yd3 (NAVFAC 2010)

Case Study 3 – Allegheny Ballistics Laboratory, WV

Key Lessons Learned

• Performance monitoring program not ideal for project goals b l h l dbecause only aqueous phase was sampled

– Aqueous phase COC concentrations only tell a small part of the storstory

– Soil sampling can provide more comprehensive data, including:• Assessment of DNAPL, sorbed, and other phases

• Much stronger basis from which to perform mass reduction calculations

• ISCO project may have been under-designed– Known DNAPL disposal and very high TCE concentrations in GW

83

– Low oxidant dose and very low number of PVs deliveredRITS Fall 2010: Is ISCO Right for Your Site?Case Study 3 – Allegheny Ballistics Laboratory, WV

Case Study 4 – NAS Alameda Point Site 14 (2007 to 2009)

• COC ConditionsVi l hl id (VC) lti f l t t f ll d b ti l d ti – Vinyl chloride (VC) resulting from solvent storage followed by partial reductive dechlorination, maximum concentrations in GW: VC 380 µg/L, no DNAPL

• Geologic Conditions– Heterogeneous fine to medium sand fill materials, average K = 8 ft/day

• Project Goals– Risk-based VC concentration 15 µg/L in

groundwater

• ISCO Full Scale Design

IR Site 14IR Site 14

• ISCO Full Scale Design– Persulfate recirculation, 3 injection events– 1 to 3 g/kg oxidant dose, 1 to 2 PVs


1 to 3 g/kg oxidant dose, 1 to 2 PVs– Bench and pilot studies implemented

Case Study 4

Photo courtesy of T. Chaudhry, NAVFAC ESC

Project Results

• Maximum VC concentration in d t d d f 380 groundwater reduced from 380

to <40 µg/L

• 70% reduction in VC mass

• Remedial goal of 15 µg/L met g µgin 20 of 25 MWs, monitoring ongoing

• Total cost $1,850,000, or$54/yd3 (NAVFAC 2010)

Photo courtesy of T. Chaudhry, NAVFAC ESC

85 RITS Fall 2010: Is ISCO Right for Your Site?Case Study 4 – NAS Alameda Point Site 14

Key Lessons Learned

• ISCO design incorporated health & safety concernsIron activation selected over base activation after verification of – Iron activation selected over base activation after verification of comparable performance in bench study

• Attempted to reduce risk to nearby Oakland Inner Harbor– Clear persulfate solution chosen over dark purple permanganate after

both oxidants performed similarly in pilot study

Observational Method used to guide ISCO application• Observational Method used to guide ISCO application– GW sampling in between ISCO events helped target next phase of work– Recirculation rates modified based on field observations– Recirculation rates modified based on field observations– Extraction wells retrofitted with vacuum to enhance flow rates

• Cost data provide good example of “economies of scale” when

86

Cost data provide good example of economies of scale when treating large sites

RITS Fall 2010: Is ISCO Right for Your Site?Case Study 4 – NAS Alameda Point Site 14




• ISCO Screening



• Case Studies

• Summary– Take-Home Messages– Acknowledgements

87

• Summary


– References– Contact Information

Take-Home Messages

1. One or more oxidants can destroy most, if not all, of the common organic COCsorganic COCs

2. Effective in situ delivery is essential3. ISCO can successfully achieve treatment goalsy g4. ISCO has great potential for successful use at some, but not all sites5. ISCO can be, and often must be, synergized with other remedies6. ISCO will normally require two or more delivery events7. ISCO can temporarily perturb subsurface conditions8 Monitoring program must be consistent with project objectives8. Monitoring program must be consistent with project objectives9. So-called “rebound” will often occur, more so at some sites than

others

88

10.The cost of ISCO varies widely

RITS Fall 2010: Is ISCO Right for Your Site?Summary

Acknowledgments: ISCO TPM Project Team

• Principal Investigators • Project Team Members– Robert Siegrist, Ph.D., Colorado

School of Mines (CSM)

– Michelle Crimi, Ph.D., Clarkson

– Fritz Krembs (CSM)

– Ben Petri, M.S. (CSM)

G N (CH2M Hill), ,University

• Co-Principal Investigators

– Gene Ng (CH2M Hill)

– Michael A. Singletary, P.E. (NAVFAC)

– Junko Munakata Marr, Ph.D. (CSM)

– Thomas A. Palaia, P.E. (CH2M Hill)– Kathryn Lowe, M.S. (CSM)

– Nancy Ruiz, Ph.D. (NAVFAC ESC)– Thomas J. Simpkin, Ph.D. (CH2M Hill)

– Tissa Illangasekare, Ph.D., P.E., DEE (CSM)


(CSM)

Summary

References

• Cooper, E., A. Livadas, T. Hanna, J. McAssey, G. Burke, and M. Martin 2006 National Survey of In Situ Soil and Groundwater Martin 2006. National Survey of In-Situ Soil and Groundwater Chemical Oxidation Design Criteria. Fifth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey, CA.

• McDade, J.M., T.M. McGuire, and C.J. Newell 2005. Analysis of , , , yDNAPL Source-Depletion Costs at 36 Field Sites. Remediation, Spring: 9-18.

• National Research Council (NRC) 2004. Contaminants in the Subsurface: Source Zone Assessment and Remediation. The N ti l A d i P W hi t D C 372


National Academies Press, Washington, D.C., 372 pp.

Summary

References (cont.)

• NAVFAC ESC 2010. Technical Report TR-2333-ENV: Cost and Performance Report for Persulfate Treatability Studies, June.e o a ce epo t o e su ate eatab ty Stud es, Ju e

• Siegrist RL, Crimi ML, Petri B, Simpkin T, Palaia T, Krembs FJ, Munakata-Marr J, Illangasekare T, Ng G, Singletary M, Ruiz N. , g , g , g y ,2009. In Situ Chemical Oxidation for Groundwater Remediation: Site Specific Engineering and Technology Application. ER-0623 Final Report. Prepared for the ESTCP, Arlington, VA, USA. http://docs.serdp-estcp.org.

• Siegrist, R.L., B.G. Petri, F.J. Krembs, M.L. Crimi, S. Ko, T.J. Si ki d T A P l i 2008 I Sit Ch i l O id ti f Simpkin, and T.A. Palaia 2008. In Situ Chemical Oxidation for Remediation of Contaminated Groundwater: Summary Proceedings of an ISCO Technology Practices Workshop. ESTCP P j t ER 0623 J

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ESTCP Project ER-0623, June.

RITS Fall 2010: Is ISCO Right for Your Site?Summary

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