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Thermal Remediation Services, Inc.

Thermal Remediation Services, Inc.

Electrical Resistance Heating for

In-Situ Remediation of Soil & Groundwater

December 10, 2002 Greg Beyke

(770) 794-1168gbeyke@thermalrs.com

www.thermalrs.com

SOLVENT

SAND

CLAY

BEDROCK

WATER TABLE

GROUNDWATER FLOW

2

PCU

3

GAC Filter

4

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Why Electrical Resistance Heating?

Why Electrical Resistance Heating?

Heating is uniform with no bypassed

regions

Heating is rapid – months vs. years

Steam is produced in-situ

Preferentially heats tight soil lenses and

DNAPL hot spots

Cost effective: most commercial, full-

scale sites range from $40-$100 per yds3

Heating is uniform with no bypassed

regions

Heating is rapid – months vs. years

Steam is produced in-situ

Preferentially heats tight soil lenses and

DNAPL hot spots

Cost effective: most commercial, full-

scale sites range from $40-$100 per yds3

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ApplicationsApplications

Low permeability & heterogeneous lithologies

DNAPL & LNAPL cleanups by aquifer and smear zone heating

Heavy hydrocarbon mobilization

Degradation enhancement (hydrolysis, bio)

Remediation underneath operating facilities, in the presence of buried utilities and hazardous waste drums

Low permeability & heterogeneous lithologies

DNAPL & LNAPL cleanups by aquifer and smear zone heating

Heavy hydrocarbon mobilization

Degradation enhancement (hydrolysis, bio)

Remediation underneath operating facilities, in the presence of buried utilities and hazardous waste drums

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In-Situ Steam Generation

In-Situ Steam Generation

HEATEDZONE

ELECTRODE ELECTRODENEUTRAL

2. Steam generation is uniform through the heated zone

1. Soil grains act as electrical resistors

150 V to600 V

<15 V

3. Discrete intervals can be heated

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Surface EquipmentSurface Equipment

Steam Condenser

500 kW PCU

Operating Electrode

Photo Courtesy of Brown and Caldwell

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Vapor Recovery System

Vapor Recovery System

ERH Power Control Unit

Water Storage TankOr Sewer

VacuumPump

Carbonor

Catox

Condenser

1

23

4

5 6

T

T

>99% of the contaminant mass

remains in the vapor state

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ERH Equipment Staging

ERH Equipment Staging

Baker Tank

500 kW PCU Steam Condenser

GAC Vessels Vacuum

Blower

CPVC pipe from wells

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Full-Scale DNAPL Cleanup the Problem*

Full-Scale DNAPL Cleanup the Problem*

DNAPL (TCE & TCA) covering about 1 acre of an industrial site

ENSR performed remediation for about 5 years and removed 30,000 pounds of TCE & TCA

DNAPL remained in four areas, mostly under a large warehouse building

Goal: Reach Tier III RBCA Cleanup Levels over entire site

DNAPL (TCE & TCA) covering about 1 acre of an industrial site

ENSR performed remediation for about 5 years and removed 30,000 pounds of TCE & TCA

DNAPL remained in four areas, mostly under a large warehouse building

Goal: Reach Tier III RBCA Cleanup Levels over entire site

*Data from the 1999 EPA Cost and Performance Report

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Full-Scale DNAPL Cleanup Site Map*Full-Scale DNAPL Cleanup Site Map*

10’ deepwaste drain

Cast ironroof drain

TCE and TCAtanks

Storm drain

Power Control Unit

Semiconductor Building

DNAPL

107 electrodes

*Data from *Data from 1999 EPA 1999 EPA Cost and Cost and

Performance Performance ReportReport

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ERH Remediation Beneath a BuildingERH Remediation Beneath a Building

Electrode

Vapor Recovery Pipe

Limited overhead

access

Photo Courtesy of Brown and

Caldwell

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Full-Scale DNAPL CleanupSubsurface Cross-SectionFull-Scale DNAPL CleanupSubsurface Cross-Section

BuildingSlab

Fill

7’

20’

HeatedZone

Electrode

Sandy Silt

Silty Clay

DNAPL

SVEWell

Clay Aquitard

SVEWell

DNAPL Pools

Electrode

18’

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Full-Scale DNAPL CleanupOperations & Results*

Full-Scale DNAPL CleanupOperations & Results*

Operations Heating (107 electrodes) started June

4, 1998 Aquifer reached boiling in 60 days Maintained above the boiling point of

TCE (73ºC) for the next 3 months

Results Tier III levels by late November 1998;

the site is now closed >15,000 pounds of VOCs removed

Operations Heating (107 electrodes) started June

4, 1998 Aquifer reached boiling in 60 days Maintained above the boiling point of

TCE (73ºC) for the next 3 months

Results Tier III levels by late November 1998;

the site is now closed >15,000 pounds of VOCs removed

*Data from 1999 EPA Cost and Performance Report*Data from 1999 EPA Cost and Performance Report

16Average Groundwater Concentrations Seven Most

Contaminated Wells*

Average Groundwater Concentrations Seven Most

Contaminated Wells*

March 1998

November 1998

cis 1,2-DCE 1,1,1-TCA TCE

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

ug/l

98.3% 99.9% 98.9%

October 1998*Data from *Data from 1999 EPA 1999 EPA Cost and Cost and

Performance Performance ReportReport

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0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

mg/l

Aa6 Ba3 D3 D7 D9 E5 F9 F13 G3 ave

Monitoring Wells

May-99

Dec-99

May-00

Do Groundwater Concentrations Rebound after

ERH Remediation?

Do Groundwater Concentrations Rebound after

ERH Remediation?

Average Additional Decrease

= 23%

two wells increased

seven wells decreased

Data from Data from ENSR reportENSR report

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Polishing MechanismsPolishing Mechanisms

Hydrolysis of Halogenated Alkanes Compounds such as TCA have a hydrolysis half-life of

less than one day at steam temperatures.

Iron Reductive Dehalogenation Steel shot used as electrode backfill provides an iron

source for reductive dehalogenation (iron filing wall)

Temperature Accelerates Reactions The above reaction rates are increased by factor of

thousands at 100°C (Arrhenius Equation)

Bioremediation by Thermophiles Thermophilic bacteria are the most effective solvent

dehalogenators and prefer 40-70°C

Hydrolysis of Halogenated Alkanes Compounds such as TCA have a hydrolysis half-life of

less than one day at steam temperatures.

Iron Reductive Dehalogenation Steel shot used as electrode backfill provides an iron

source for reductive dehalogenation (iron filing wall)

Temperature Accelerates Reactions The above reaction rates are increased by factor of

thousands at 100°C (Arrhenius Equation)

Bioremediation by Thermophiles Thermophilic bacteria are the most effective solvent

dehalogenators and prefer 40-70°C

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Full Scale DNAPL CleanupCost & Performance Data*Full Scale DNAPL CleanupCost & Performance Data*

Effectiveness Total operations took 18 weeks, five days Treated approximately 30,000 cubic yards Since completing, average groundwater VOC

concentrations have continued to decrease

Costs Total project costs were $32/cubic yard The total includes electrical costs of $6.50/cubic yard Vapor treatment was not required. If vapor treatment

had been required, the cost would have been about $41 per cubic yard.

Effectiveness Total operations took 18 weeks, five days Treated approximately 30,000 cubic yards Since completing, average groundwater VOC

concentrations have continued to decrease

Costs Total project costs were $32/cubic yard The total includes electrical costs of $6.50/cubic yard Vapor treatment was not required. If vapor treatment

had been required, the cost would have been about $41 per cubic yard.

*Data from the 1999 EPA Cost and Performance Report*Data from the 1999 EPA Cost and Performance Report

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TCE DNAPL RemediationAir Force Plant Four

Fort Worth, Texas

TCE DNAPL RemediationAir Force Plant Four

Fort Worth, Texas

Photo Courtesy of

URS

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ERH Remediation BeneathAir Force Plant Four

ERH Remediation BeneathAir Force Plant Four

SVE piping

electrical c

able electrode

SVE well

Photo Courtesy of

URS

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Lowry Landfill System Layout

Lowry Landfill System Layout

South Waste Pit

2000 kW PCU

Thermal Oxidizers

Cables to the Electrode

Field

Electrode Field