Life Cycle Assessment of ISTD

and Improving the Sustainability

of Source Removal

Ralph S. Baker (rbaker@terratherm.com) and Steffen Griepke Nielsen

(TerraTherm, Inc., Gardner, MA, USA)

Gitte Lemming

(Technical University of Denmark, Lyngby, Denmark)

Maiken Faurbye, Niels Ploug and Jesper Holm

(Krüger A/S, Søborg, Denmark)

Overview

• Reerslev Site Description

• Life Cycle Assessment

• Remedy Selection

• ISTD Design and Implementation

• Results

• Conclusions

2

Reerslev – near Copenhagen, Denmark

3

Well Field

Source

Plume –

secondary

aquifer

Plume –

primary aquifer

Reerslev, Denmark Reerslev – Locus

4

Solhøj Municipal Well Field Supplied 50,000 homes 5

Conceptual Site Model

1.600 mg/m3

Well Field

Clayey till: 0-8 m

Secondary aquifer

Clay: 23-25 m

Chalk Primary aquifer

Hot spot

area

<1 µg/l 13 µg/l

400 µg/l

Sand: 8-23 m

6

Initial Remedies

SVE system

P&T system

Well field

Clayey till

SandSecondary aquifer

Clay

Chalk

Primary aquifer

Hot spot area

SVE system

P&T system

Hot spot area

7

Reerslev – Site Description

8

Legend:

Risk of DNAPL

High soil

concentrations

Diffuse

contamination -

not to be treated

Houses

Technology Evaluation

• Excavation and off site treatment

• In Situ Thermal Desorption (ISTD)

• Cutting off hotspot by Soil Vapor Extraction

(SVE)

9

Evaluation parameters

Activities Impacts Effects

Se

ttin

g-u

p

Transport Excavation Drilling Building equipment Commissioning

Con

sum

able

s

Power Fuel/gas Plastic Concrete Iron/steel Activated carbon

Reso

urc

es

Inadequate raw materials Metals Sand/gravel Water

Op

era

tion

Operation period Electrical effect Supervision Service

Em

issio

ns

CO2, CO, NOx, SO4 VOC’s Noise and vibrations Dust or odor

En

vir

on

men

t

Global warming Acidification Toxicity Landfill Dangerous waste

Dis

man

tlin

g

Transport Waste

Exp

osu

re

Risk of fire or explosions Dangerous work Inconvenience/disturbance of neighbors

Hum

an

Working environment Inconvenience/disturbance of neighbors

Life Cycle Assessment (LCA) (Pfeilschifter et al. 2007)

10

LCA, cont. (Pfeilschifter et al. 2007)

Carbon footprint – ton CO2 equivalents

ton

CO

2 e

qu

iva

len

ts

Excavation SVE

30 years SVE

100 years

ISTD

8 months ISTD

12 months 80 km

11

LCA, adjusted for: Actual ISTD Duration; Transport Distance

Carbon footprint – ton CO2 equivalents

ton

CO

2 e

qu

iva

len

ts

Excavation SVE

30 years SVE

100 years ISTD

8 months

ISTD

12 months 5.5 months 140 km

12

LCA, cont. (Pfeilschifter et al. 2007)

Environmental Impacts

Excavation and off site treatment

SVE (30 years)

ISTD (8 months)

ISTD (12 month)

SVE (100 years)

Emissions Toxicity Waste

1 PE = 8.7 ton CO2

13

Comparison of Methods

“Most likely” scenarios are marked

Green = best environmental performance

Red = worst performance

Yellow = intermediate environmental performance

LCA, cont. (Pfeilschifter et al. 2007)

Factoring in all considerations, heating was

selected as the preferred remedy 14

Modelling objectives – size of area to be treated using ISTD and flux-reduction to be achieved

25 900 32.4

10 400 1.6

1 1500 0.5

0.1 2100 0.1

Concentration Area Flux

34.6 kg/y is the

current flux of PCE

into the vadose

zone underlying

the source area

(mg-PCE/kg) (m2) (kg/y)

Remediation scenarios considered:

• Reduction to 10 mg/kg (900 m2) Flux 2.2 kg/y

• Reduction to 1 mg/kg (1300 m2) Flux 1.2 kg/y

• Reduction to 0.1 mg/kg (1300 m2) Flux 0.7 kg/y

• Reduction to 0.1 mg/kg ( 2800 m2) Flux 0.2 kg/y (original

design)

• Reduction to 0.1 mg/kg ( 6000 m2) Flux 0.07 kg/y (complete

remediation)

Scenario should achieve < 1 µg-PCE /l at well field

Selection of Remedial Goals

15

ISTD Stats

• 11,500 m3 soil treated

• 1,300 m2

• 147 heater wells

• 21 extraction points

• 30 thermocouple wells

• 240 temperature

monitoringpoints

• 169 days of heating

16

17

18

19

20

ISTD Temperature Progression I

21

ISTD Temperature Progression, cont.

22

ISTD operation

0

200

400

600

800

1000

1200

1400

1600

1800

2000

17-maj 06-jul 25-aug 14-okt 03-dec 22-jan

PCE [mg/m3]

0

10

20

30

40

50

60

70

80

90

100

oC

PCE [mg/m³]

Avg. Temp

0

200

400

600

800

1000

1200

1400

1600

1800

2000

17-maj 06-jul 25-aug 14-okt 03-dec 22-jan

PCE [mg/m 3]

0

10

20

30

40

50

60

70

80

90

100

oC

PCE [mg/m³]

Avg. Temp

Extracted PCE during ISTD

2,500 kg of PCE removed 23

Results of ISTD Heating

0

1

2

3

4

5

6

7

8

0,001 0,01 0,1 1 10 100 1000 10000

Concentration Reerslev [mg/kg]

De

pth

[m

bg

s]

D.L. DK soil criteriaCleanup criteria

0

1

2

3

4

5

6

7

8

0,001 0,01 0,1 1 10 100 1000 10000

Concentration Reerslev [mg/kg]

De

pth

[m

bg

s]

D.L. DK soil criteriaCleanup criteria

0

1

2

3

4

5

6

7

8

0,001 0,01 0,1 1 10 100 1000 10000

Concentration Reerslev [mg/kg]

De

pth

[m

bg

s]

D.L. DK soil criteriaCleanup criteria

Actual heating time: 5.5 months

24

Conclusions

• LCA selected ISTD over excavation and cold SVE

• Actual ISTD Heating Time = 5.5 months (46% of the

LCA estimate of 1 year)

• Energy consumption ~ 340 kWh/m3 (72% of the

LCA estimate)

• PCE concentrations were reduced 17 times below

cleanup criteria 99.99%

• Total ISTD budget = $3.8M (88% of LCA est.)

25

Sustainability in Context of Source Removal

26

The carbon footprint associated with electrically heating 1 m3 of contaminated soil digging and hauling it 140 km (85 mi)

Meanwhile, in-situ treatment has a lower neighborhood impact, and is environmentally friendly

With In Situ Thermal Remediation (ISTR), liability is eliminated, not merely moved to another location

Certain outcome; short time-frame; highly sustainable

Hotspots Improvement initiatives Total reduction potential and division

between initiatives

IST

D

Electricity use • Heating 12h/d Environmental

impacts:

10%

Resource

depletion:

20%

Above grade

materials

• Vapor cap (concrete sandwich)

• Biobased activated carbon

Well field

materials

• Substitution in nickel and stainless

steel

SE

E

Energy use • Change to condensing boiler Environmental

impacts:

21%

Resource

depletion:

9%

Above grade

materials

• Vapor cap (concrete sandwich)

• Biobased activated carbon

Well field

materials

• Change to fiberglass liners

ET

-DS

P

Electricity use • Heating 12h/d Environmental

impacts:

13%

Resource

depletion:

8%

Above grade

materials

• Vapor cap (concrete sandwich)

• Biobased activated carbon

Transportation • Use of experts and equipment from

Denmark

ET-DSP: Electro-Thermal Dynamic Stripping Process

Heating 12h/d

Vapor cap

Biobased AC

Heating 12h/dVapor capBiobased ACNi and SS alloys

Heating 12h/dVapor capBiobased ACTransport

Heating 12h/dVapor capBiobased ACTransport

Summary of conclusions for ISTD, SEE and ET-DSP

(Lemming et al. 2012) 27

References Baker, R.S., T. Burdett, S.G. Nielsen, M. Faurbye, N. Ploug, J. Holm, U. Hiester, and V. Schrenk. 2010. “Improving the

Sustainability of Source Removal.” Paper C-027, in K.A. Fields and G.B. Wickramanayake (Chairs), Remediation of

Chlorinated and Recalcitrant Compounds—2010. Seventh International Conference on Remediation of Chlorinated and

Recalcitrant Compounds (Monterey, CA; May 2010). Battelle Memorial Institute, Columbus, OH.

Faurbye, M., Jensen, M., Rugge, K., Nielsen, S.G., Heron, G., Baker, R.S., Johansen, P., Tolstrup Karlby L. 2009.

“Thermal in-situ remediation – a sustainable choice.” Green Remediation Conference, Copenhagen.

Lemming, G., P. Bjerg, K. Weber, J. Falkenberg, S. Nielsen, R. Baker, G. Heron, M. Terkelsen and C. Jensen. 2012.

“Environmental Optimization of In Situ Thermal Remediation Technologies using Life Cycle Assessment (I).” In: In:

Remediation of Chlorinated and Recalcitrant Compounds – 2012. Eighth International Conference on Remediation of

Chlorinated and Recalcitrant Compounds (Monterey, CA; May 2012). Battelle Memorial Institute, Columbus, OH.

Pfeilschifter, E., E. Søgaard, G. Lemming, and M. Møller. 2007. LCA of three soil remediation technologies for PCE

contamination at MW Gjøesvej, Reerslev. Unpublished report, Course 42372: Life Cycle Assessment of Products and

Systems, Dec. 6, 2007, Technical University of Denmark, Lyngby, Denmark.

Ploug, N., M. Jensen, J. Holm, P.J. Jensen, H.E. Steffensen, S.G. Nielsen, and G. Heron. 2010. “Thermal Treatment –

How Close Can You Go and Is It Safe to Humans?” Paper E-013, in K.A. Fields and G.B. Wickramanayake (Chairs),

Remediation of Chlorinated and Recalcitrant Compounds—2010. Seventh International Conference on Remediation of

Chlorinated and Recalcitrant Compounds (Monterey, CA; May 2010). Battelle Memorial Institute, Columbus, OH.

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