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Full-Scale Bioremediation at Multiple Sites: Recirculation versus Passive DistributionFull-Scale Bioremediation at Multiple Sites: Recirculation versus Passive Distribution

Randy Kurth, Shaw E&I

Rebecca Rogers, Belinda Price, Dirk Pohlmann, Tarek Ladaa, Shaw E&ILori Combass, Restoration Program Manager, Moody AFB

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22

OutlineOutline

Anaerobic BioremediationImplementationMoody Air Force Base

Site DescriptionAnaerobic Bioremediation Treatment AreasDesign and ImplementationPerformance Monitoring Results

Comparison of Active versus Passive DistributionLessons Learned

Anaerobic BioremediationImplementationMoody Air Force Base

Site DescriptionAnaerobic Bioremediation Treatment AreasDesign and ImplementationPerformance Monitoring Results

Comparison of Active versus Passive DistributionLessons Learned

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Anaerobic BioremediationAnaerobic BioremediationDefn: Addition of an electron donor (i.e. carbon source) and/or microorganisms within subsurface to stimulate anaerobic biodegradation of chlorinated ethenes

Defn: Addition of an electron donor (i.e. carbon source) and/or microorganisms within subsurface to stimulate anaerobic biodegradation of chlorinated ethenes

Add microbial consortium containing viable Dehalococcoides sp.

Incomplete Dechlorination

Add buffer (bicarbonate)Low pH

Add nutrients (ammonia and phosphate) Limited Nutrients

Add carbonLimited Carbon

Add carbon – aerobic biodegradation of carbon will consume the dissolved oxygen present

Aerobic Conditions

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ImplementationImplementation

• Active vs. Passive Distribution– Series of injection/extraction wells

- “Pull” or recirculate carbon through treatment zone– Multiple injection points

- Distribution achieved by ambient groundwater flow

• Distribute carbon/microorganisms in treatment zone- Utilize existing extraction wells, where possible- Reduce field time associated with injection- Reduce potential for follow-up injections- Distribution time less than in situ longevity of carbon source

• Active vs. Passive Distribution– Series of injection/extraction wells

- “Pull” or recirculate carbon through treatment zone– Multiple injection points

- Distribution achieved by ambient groundwater flow

• Distribute carbon/microorganisms in treatment zone- Utilize existing extraction wells, where possible- Reduce field time associated with injection- Reduce potential for follow-up injections- Distribution time less than in situ longevity of carbon source

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Moody Air Force Base, Valdosta, GeorgiaMoody Air Force Base, Valdosta, Georgia

Site Characteristics

• Chlorinated Ethenes- TCE from 100 – 10,000 µg/L- Little or no cis-1,2-DCE, VC

• Aquifer Conditions - DO >1 mg/L- ORP >200 mV- pH between ~4.5 – 6.5

• Active Remediation Performance Standards- TCE/DCE 50 – 1,000 µg/L

Chlorinated Ethene Sites Treated with Anaerobic Bioremediation

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Golf Course Area (SS-39)Anaerobic Bioremediation Pilot Study

Golf Course Area (SS-39)Anaerobic Bioremediation Pilot Study

A pilot study was initiated in December 2003 to evaluate the use of anaerobic bioremediation using a groundwater recirculation system.

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Golf Course Area (SS-39)Pilot Study Results

Golf Course Area (SS-39)Pilot Study Results

TCE concentrations in DEC 03(prior to system start-up)

TCE concentrations in JAN 05(two years post system start-up)

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Golf Course Area (SS-39)Expanded Groundwater Recirculation System

Golf Course Area (SS-39)Expanded Groundwater Recirculation System

Expanded System

• TCE > 500 µg/L

• 10 Injection Wells

• 8 Extraction Wells

• Carbon SourceSodium Lactate

• BioaugmentationSDC-9

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Former Fire Training Area (FT-07)Anaerobic Bioremediation Pilot Study

Former Fire Training Area (FT-07)Anaerobic Bioremediation Pilot Study

• HRC injection November 2002

• HRC injection December 2003

• Bioaugmentation June 2004

A pilot study was initiated in November 2002 to evaluate direct injection and distribution via ambient groundwater flow.

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Former Fire Training Area (FT-07)Pilot Study Results

Former Fire Training Area (FT-07)Pilot Study Results

VOC and Ethene Trends in Well TW02 at FT-07Moody Air Force Base, Valdosta, Georgia

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

Oct-02 May-03 Sep-03 May-04 Jan-05 5-Oct

cis

-DC

E C

onc.

( μ

g/L)

0

50

100

150

200

250

300

TCE,

VC

& E

then

e C

onc.

( μ

g/L)

cis-DCE TCE VC Ethene

November 2002, 1st HRC Application,

June 2004, Lactate and SDC-9 Application

November 2003, 2cd HRC Application

1,000 μg/L Active remediation Performance

August and Nove 2005, Lactate and SDC-9

(230 ug/L) (45 ug/L) (0.97 ug/L)

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1111

Former Fire Training Area (FT-07)Expanded Passive Delivery System

Former Fire Training Area (FT-07)Expanded Passive Delivery System

Expanded Treatment Area

• cis-1,2-DCE > 1,000 µg/L• 57 Injection Wells• 20-ft Grid Spacing• Carbon Source – Sodium Lactate• Bioaugmentation – SDC-9

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1212

Former Fire Training Area (FT-07)Lactate Distribution via Gravity Feed

Former Fire Training Area (FT-07)Lactate Distribution via Gravity Feed

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1313

Flightline Storm Drain Outfall & Mission Lake (SD-16)Full-Scale Anaerobic Bioremediation

Flightline Storm Drain Outfall & Mission Lake (SD-16)Full-Scale Anaerobic Bioremediation

Treatment Area

• TCE > 100 µg/L

• 118 Injection Wells

• 25-ft Grid Spacing

• Carbon SourceEmulsified Oil

• pH BufferSodium Bicarbonate

• BioaugmentationSDC-9

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1414

Flightline Storm Drain Outfall & Mission Lake (SD-16)Grid Application of Emulsified Oil and Bioaugmentation

Flightline Storm Drain Outfall & Mission Lake (SD-16)Grid Application of Emulsified Oil and Bioaugmentation

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1515

Flightline Storm Drain Outfall & Mission Lake (SD-16)Performance Monitoring Results

Flightline Storm Drain Outfall & Mission Lake (SD-16)Performance Monitoring Results

Carbon, Metabolic Acids, and pH Trends over TimeMonitoring Well SD16-MW111

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1616

Flightline Storm Drain Outfall & Mission Lake (SD-16)Performance Monitoring Results

Flightline Storm Drain Outfall & Mission Lake (SD-16)Performance Monitoring Results

Geochemical Trends over TimeMonitoring Well SD16-MW111

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Flightline Storm Drain Outfall & Mission Lake (SD-16)Performance Monitoring Results

Flightline Storm Drain Outfall & Mission Lake (SD-16)Performance Monitoring Results

VOC Concentration Trends over TimeMonitoring Well SD16-MW111

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Flightline Area (SS-38)Full-Scale Anaerobic Bioremediation

Flightline Area (SS-38)Full-Scale Anaerobic Bioremediation

Treatment Areas

• TCE and 1,1-DCE > 400 µg/L

• Locations 1 and 5Passive Distribution

• Location 3 Groundwater Recirculation

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Flightline Area (SS-38)Grid Application of Emulsified Oil and Bioaugmentation

Flightline Area (SS-38)Grid Application of Emulsified Oil and Bioaugmentation

Location 1 Treatment Area

• 37 Injection Wells• 25-ft Grid Spacing• Emulsified Oil, Sodium

Bicarbonate, and SDC-9

Location 5 Treatment Area

• 9 Injection Wells• 25-ft Grid Spacing• Emulsified Oil, Sodium

Bicarbonate, and SDC-9

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2020

Flightline Area (SS-38)Performance Monitoring Results

Flightline Area (SS-38)Performance Monitoring Results

VOC Concentration Trends over TimeMonitoring Well SS38-MW078

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2121

Flightline Area (SS-38)Anaerobic Bioremediation w/ Groundwater Recirculation

Flightline Area (SS-38)Anaerobic Bioremediation w/ Groundwater Recirculation

Location 3 Treatment Area• 1 Horizontal Injection Well• 1 Horizontal Extraction Well• Carbon Source – Lactate• Bioaugmentation – SDC-9

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Flightline Area (SS-38)Performance Monitoring Results

Flightline Area (SS-38)Performance Monitoring Results

ORP Readings in Treatment Area Monitoring Wells

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2323

Flightline Area (SS-38)Performance Monitoring Results

Flightline Area (SS-38)Performance Monitoring Results

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2424

Flightline Area (SS-38)Performance Monitoring Results

Flightline Area (SS-38)Performance Monitoring Results

TCE concentrations in April 2005(prior to system start-up)

TCE concentrations in January 2006(9-months post system start-up)

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Northeast Landfill (LF-04)Full-Scale Barrier Application of Anaerobic Bioremediation

Northeast Landfill (LF-04)Full-Scale Barrier Application of Anaerobic Bioremediation

Treatment Areas

• TCE > 100 µg/L• 180 Injection Wells• 10-ft Spacing in Rows• 100-ft between Barriers• Carbon Source – EOS• Bioaugmentation – SDC-9

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Active versus Passive DistributionActive versus Passive Distribution

Performance Monitoring Data Not Yet AvailableLF-04 (passive)

Yes9-12 months3-6 monthsSS-38 (passive)

Yes< 3 months< 3 monthsSS-38 (active)

Yes9-12 months3-6 monthsSD-16 (passive)

OK3-6+ monthsNAFT-07 (passive)

Yes< 3 months< 3 monthsSS-39 (active)

Adequate Distribution

Daughter Products

Anaerobic Conditions

Site

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Active DistributionActive Distribution

Advantages+ Distribution of amendments < 3 months+ Reductive dechlorination initiated < 3 months+ Faster clean-up time+ Treat larger area with fewer injection wells+ Easy to perform follow-up carbon injections/bioaugmentation

Disadvantages- Higher O&M costs- Higher potential for biofouling in injection/extraction wells- Site access restrictions may prevent installation and/or operation

of a groundwater recirculation system

Advantages+ Distribution of amendments < 3 months+ Reductive dechlorination initiated < 3 months+ Faster clean-up time+ Treat larger area with fewer injection wells+ Easy to perform follow-up carbon injections/bioaugmentation

Disadvantages- Higher O&M costs- Higher potential for biofouling in injection/extraction wells- Site access restrictions may prevent installation and/or operation

of a groundwater recirculation system

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Passive DistributionPassive Distribution

Advantages+ Lower O&M costs+ Potential use in areas where site access restricts the installation

and/or operation of a groundwater recirculation system+ Less biofouling in injection wells

Disadvantages- Longer lag time associated with distribution of carbon and/or

microorganisms than in groundwater recirculation system - Longer clean-up time- Higher labor costs associated with follow-up injections

Advantages+ Lower O&M costs+ Potential use in areas where site access restricts the installation

and/or operation of a groundwater recirculation system+ Less biofouling in injection wells

Disadvantages- Longer lag time associated with distribution of carbon and/or

microorganisms than in groundwater recirculation system - Longer clean-up time- Higher labor costs associated with follow-up injections

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Lesson LearnedLesson Learned

What is the most effective delivery method for full-scale application?

Both active distribution and passive distribution are effective means for implementing anaerobic bioremediation.

The most effective method for a particular site depends upon:- site access restrictions- consideration of aquifer characteristics- treatment area dimensions- cleanup time

Effectiveness of anaerobic bioremediation is contingent upon achieving adequate distribution of amendments within the treatment zone.

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Questions?Questions?