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Rapid & Complete In Situ Bioremediation of

Chlorinated Solvents Using

Enhanced Anaerobic Dechlorination (EAD)

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1) Its All About Delivery: Our ISD™ systems provide a powerful delivery platform to support site-wide anaerobic degradation of chlorinated solvents

Roadmap

ISDIn Situ

Systems

TMDelivery

2) Full-scale Case Study: Field applications of our ISD groundwater recirculation approach validates this remediation strategy

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ISD Concept

Effective substrate delivery via 24/7 GW recirculation - NO SLUG INJECTIONS Highly soluble substrate, plus nutrients, to grow active biomass in porespace

Max. microbial activity, ↓ ORP, methanogenic cond., ↑ dissolution, no rebound

Ground Surface

VADOSE ZONE

SATURATEDZONEConfining Layer

ISD SystemSubstrateNutrientMetering

DeliverySystem

Contact between substrate and chlorinated solvents

Rapid SolventDegradation

Substrate-amended H2O

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EAD Process

FoodFood

Electron Electron donordonor

Chlorinated hydrocarbons:Chlorinated hydrocarbons:

PCEPCE

TCETCE

DCEDCE

VCVC

Competing electron Competing electron acceptorsacceptors::

OO22

NONO33--

MnMn4+4+

FeFe3+3+

SOSO442-2-

NN22

MnMn2+2+

FeFe2+ 2+

HH22SS

Ethene / EthaneEthene / Ethane

NUTRIENTSNUTRIENTS::

NN

PP

KK

Trace MetalsTrace Metals

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Advantages of Groundwater Recirculation w/ ISD™

– Programmable Automation– Direct hydraulic influence and capture– Contact – dissolved & adsorbed (source, distal plume)– Biomass generation, site-wide activity

Inexpensive Electron Donor - CarBstrate™

– Nutrient-amended Carbohydrate – low cost ($2/lb)

Installation/Interpretation Services

– Equipment installation & training– Monthly Interpretation/Evaluation of Data

Timeframe

– ISD results in months vs. years– Minimal O&M and cost (pulsed vs. continuous)

ETEC’s EAD Process

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Pilot-scale Data:

Industrial SiteEugene, Oregon

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OR Case Study Site Plan

Mobile ISDSystem

MW-1

Groundwater Flow Direction

Extraction Wells

LEGEND

Monitoring Wells

Injection Wells

MW-2

MW-3

MW-4

Extraction Flow Line

Injection Flow Line

15 m

9 m

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TMW-3 Results

Observations

– CAH concentrations increased 2-3 fold during 1st week, no PCE at TMW-3

– DCE from 360 to 2,000 ppb – Initial total CAH 3.8 μmol/L, with a high of 22.3 μmol/L – 8 months, no rebound, cis-DCE and VC (6 and <1 ppb)

TMW-3 Chlorinated Solvent and Ethene/Ethane Concentrations

0

200

400

600

800

1000

1200

1400

1600

1800

2000

DAYS

cis

-DC

E C

on

ce

ntr

atio

ns

(p

pb

)

0

20

40

60

80

100

120

140

160

PC

E,

TC

E,

VC

an

d E

the

ne

/Eth

an

e

Co

nc

en

tra

tio

ns

(p

pb

)

PCE

cis-DCE

TCE

VC

Ethene/Ethane

Operating Parameters

– 3 weeks – 178,000 liters recirculated – 180 kg of CarBstrate™

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Full-scale Case Study:

Industrial SiteEugene, Oregon

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2006 Full-scale RA• Solid pilot-test data showing rapid, complete

dechlorination of solvents supported full-scale in situ remedial action

• Full-scale conducted from June-Sept 2006 to remediate source area (122 m x 91 m x 6 m) using 31 Injection/extraction wells

• 150-lpm ISD system, touch-screen and flexible PLC system

• 12-18 month estimated timeframe to reduce CAHs by 90%, achieved goal in 6 months

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Full-scale system has 11 EWs and 20 IWs. To date, most data has been collected from EW-3, 6, 7, and 10. Samples collected from EW-7 shows source zone concentrations.

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Over 3 months:

Recirculated over >8.7 million liters in 3 months

Introduced 3,720 kg substrate

1-visit/week

Minimal down time

Minimal Fouling

Some LNAPL (diesel and Bunker C)

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14

Touch Screen PLC:

Alarm Conditions,

Troubleshooting

Flexible injection times

Auto-dialer/Telemetry

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2006 Results

– Cis-DCE increased significantly, then began to decline. A max concentration of 500 ppb PCE should generate 291 ppb of cis-DCE, but we see up to 1,300 ppb.

EW-03

0

100

200

300

400

500

600

0 20 40 60 80 100 120 140 160

DAYS

PC

E, T

CE

, VC

, E

the

ne

/eth

an

e (

pp

b)

0

200

400

600

800

1000

1200

1400

cis

-DC

E C

on

ce

ntr

ati

on

(p

pb

)

PCE

TCE

VC

ethene/ethane

cis-DCE

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EW-3 Molar Concentrations

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

0 16 22 48 83 154

Time- Days

Mo

lar

Co

nc

en

tra

tio

n

um

ol/

L

PCE

TCE

cis-DCE

VC

Ethene/ethane

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2006 ResultsEW-6

0

50

100

150

200

250

300

350

400

450

500

0 20 40 60 80 100 120 140 160

Days

PC

E, T

CE

, VC

, et

hen

e/et

han

e C

on

cen

trat

ion

s (p

pb

)

0

500

1000

1500

2000

2500

3000

3500

cis-

DC

E C

on

cen

trat

ion

(p

pb

)

PCE

TCE

VC

ethene/ethane

cis-DCE

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EW-6 Total Molar Concentrations

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 16 22 48 83 154

Time- Days

To

tal

Mo

lar

Co

nc

en

tra

tio

ns

u

mo

l/L

PCE

TCE

cis-DCE

VC

Ethene/ethane

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EX-7Date PCE

(ppb)TCE (ppb)

cis-DCE (ppb)

VC (ppb)

Ethene/ethane (ppb)

8/22/06 Day 48

6,700 4,400 10,000 <200 50

9/26/06 Day 83

330 <100 3,500 1,100 763

12/6/06

Day 154

220 55 160 22 5.1

Observations

– First sample event shows significant concentrations of PCE/TCE even after 48 days of recirculation, with dechlorination to cis-DCE ongoing during this time.

– No significant VC after 48 days, and ethene still low.

– VC increased significantly, but nothing compared to the parent concentrations

– Generated biomass expected to continue to stimulate dechlorination for another year

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Chlorinated EthanesEW-3

Chlorinated Ethanes Mole Fractions

0

10

20

30

40

50

60

70

80

Time

Mo

le F

rac

tio

n (

Pe

rce

nt)

1,1,1-Trichloroethane 29.2 53.1 16.6 4.3 1.9 1.7

1,1-Dichloroethane 15.1 30.3 55.2 66.5 57.4 24.3

Chloroethane 55.8 16.6 28.2 29.3 40.8 73.9

7/5/2006 (B) 07/21/06 07/27/06 08/22/06 09/26/06 12/07/06

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Full-scale Comments• Approach rapidly transforms ppm levels SITE-WIDE!• Enhanced desorption observed during recirculation• No downgradient change in cVOC concentrations;

hydraulic capture successful!• LNAPL did not prevent implementation• Nutrient demand (N and P) higher than calculated• Results very similar to pilot-test. Shut-down Sept.

2006, TOC low at all locations, now biomass acting as substrate over the next several months/years. No cost associated with this, except analytical/sampling labor.

• Chlorinated Ethanes treated site-wide• Overall Costs ~$270K, treatment area 68,000 CM:

$4/CM

CONCLUSIONS• Soluble substrate + nutrients + recirculation + infrastructure = rapid

dechlorination• Works w/ varying conditions (low/high flow, ppm or ppb, co-mingled

or not) • Control subsurface conditions/microbial needs (NOT ABOUT THE

BUGS)• Total Mass of Solvents is Higher, Desorption is crucial to achieve low

level remedial goals• Nutrient Concerns (rapid uptake), higher than theoretical• Limited Biofouling (pressure inj., pulsed delivery)• Site Characterization & Infrastructure are CRITICAL!• Nitrate/phosphate, some metals (hex chrome), perchlorate, 1,4-

dioxane, treatment possible with this approach• Cost Range is cheaper than excavation/disposal ($2-8/CM)• Time comparison is like no other biological approach, kinetics much

higher