www.urscorp.com field-scale application of in situ reductive dechlorination for high concentrations...
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Field-Scale Application of in situ Reductive Dechlorination for High Concentrations of Mixed Solvents in Complicated Conditions
– Northern France
Dr Richard Sumner – URS Corporation (Paris)Dr Jeremy Birnstingl – Regenesis Ltd. (UK)
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Background Former Dry Cleaner Site Contaminated area: 1.000 m2
Representative concentrations Chlorinated ethenes (TCE etc) – 20.000 µg/L Chlorinated ethanes (TCA etc) – 10.000 µg/L Chlorinated methanes (DCM) – 5.000 µg/L
Buildings covering ~50% of plume
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Complications
Practical – access and disturbance
Geotechnical – risk of subsidence
Geological – risk of pathway exacerbation
Public health – proximity of human receptors Requirement to ensure full dechlorination (no VC
stall)
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Practical Complications
Built-up area – noise / nuisance concerns
50% of plume located beneath site buildings
Source zone adjacent to residential properties
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Geotechnical Complication
Dual Phase Extraction initially considered
Geotechnical assessments undertaken
Risk of fines wash-out leading to subsidence
Advection-based in situ remediation high risk
Diffusive in situ remediation selected – HRC®
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Source Area
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Source area adjacent to occupied residential properties
Disturbance issues Risk / receptor issues Subsidence issues –
overcome by selection of passive technology
Measures adopted: Vadose vapour monitoring
and venting installation Noise monitoring and
management during injection
TCE ≤ 20.000 µg/LTCA ≤ 10.000 µg/LDCM ≤ 5.000 µg/L
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Hydrogen Hydrogen Release Release
CompoundCompound®®
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Formation of an Ester
Glycerol Polylactate Ester = HRC®
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Why?Why? Accelerated Remedial Closure:
Hydrogen creates anaerobic plume and accelerates biodegradation 10x – 100x
Time Release of Hydrogen saves money: Reduced installation costs (simple to apply) NO remedial hardware:
Design costs Equipment capital costs Equipment O&M costs Ongoing site disturbance
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Geological Complication Shallow gravelly silt 0.75 – 3.0 mbgl
Medium permeability Heavy contamination
Silty sand layer 3.0 – 5.5 mbgl Low permeability Medium contamination
Coarse gravels 5.5 – 10 mbgl High permeability Low – medium contamination (still requires treatment)
Risk of Pathway Creation – 92 HRC® injection points
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Solution: ‘Top down’ and
‘bottom up’ injection
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Application by GeoProbe®
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HRC®
directlyinjected usinggrout pump
41 kg HRC per point92 injection points 6 vertical metres
~ 0.15% of pore volume
Easy injection, minimal hydrogeological
disruption
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Treatment Results
Predicted results (theory based on other sites)
Actual results (field performance of this site)
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Redox
PCE
Chlorinated Ethenes
cis-1,2-DCE
TCE
VC Ethene
Distance Downgradient (barrier treatment) Time (plume treatment)
Results – predicted
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Results – actual (Cl-ethenes)
Source Area - Well PW2
0
1,000
2,000
3,000
4,000
5,000
6,000
06 October 2003
25 November 2003
14 January 2004
04 March 2004
23 April 2004
12 June 2004
01 August 2004
20 September 2004
09 November 2004
29 December 2004
17 February 2005
Co
nce
ntr
atio
n (
ug
/L)
TCE
Cis-DCE
VC
HRC Injection #1
HRC Injection #2
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Results – actual (Cl-ethenes) Source Area - Well PP1
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
oct.-03
nov.-03
janv.-04
mars-04
avr.-04
juin-04
août-04
sept.-04
nov.-04
déc.-04
févr.-05
Co
nce
ntr
atio
n (
ug
/L)
TCE
Cis-DCE
VC
HRC Injection #1
HRC Injection #2
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Source Area - Well PZ3 / PZ3 bis.
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
oct.-03
nov.-03
janv.-04
mars-04
avr.-04
juin-04
août-04
sept.-04
nov.-04
déc.-04
févr.-05
Co
nce
ntr
atio
n (
ug
/L)
TCE
Cis-DCE
VC
HRC Injection #1
HRC Injection #2
Results – actual (Cl-ethenes)
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Results – actual (Cl-ethanes) Source Area - Well PW2
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
Co
nce
ntr
atio
n (
ug
/L)
TCA
DCA
CA
HRC Injection #1
HRC Injection #2
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Source Area - Well PP1
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
2,000
oct.-03
nov.-03
janv.-04
mars-04
avr.-04
juin-04
août-04
sept.-04
nov.-04
déc.-04
févr.-05
Co
nce
ntr
atio
n (
ug
/L)
TCA
DCA
CA
HRC Injection #1
HRC Injection #2
Results – actual (Cl-ethanes)
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Results Summary
TCE Concentrations (µg/L) TCA Concentrations (µg/L)
Well Day 0 Day 430 % Red. Well Day 0 Day 430 % Red.
PP-1 6800 0.6 >99% PP-1 780 9 99%
PW1 37 10 73% PW1 3800 810 79%
PW2 4800 110 98% PW2 8200 68 >99%
PW3 41 1 98% PW3 260 6 98%
PW6 12 0 100% PW6 56 160 (increase)
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Results – actual (Cl-methanes)
Evolution des teneurs en DCM
0
1000
2000
3000
4000
5000
6000
7000
Oct-03
Nov-03
Jan-04
Mar-04
Apr-04
Jun-04
Aug-04
Sep-04
Co
nc
en
tra
tio
ns
en
µg
/l
PZ3 /PZ3bis
PW2
HRC Injection
Chloromethane non-detect throughout study (both wells)
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Dichloromethane (DCM) Results
Well PZ3 /PZ3bis Well PW2
Date µg/L Date µg/L
Oct-03 6100 Oct-03 3900
Dec-03 1500 Dec-03 220
Jan-04 0.1 Jan-04 0.1
Feb-04 1300 Feb-04 350
Mar-04 4000 Mar-04 520
Apr-04 3400 Apr-04 160
May-04 3200 May-04 92
Jun-04 1400 Jun-04 15
Aug-04 (no data) Aug-04 26
Oct-04 550 Oct-04 28
% Reduction 91% % Reduction 99%
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Cost Comparisons Total HRC project cost approx. €300.000
(Fieldwork, 2 years monitoring and reporting, HRC material)
Comparative dual-phase extraction cost approx.
€400.000 - €500.000 €100.000 system installation €100.000 per year O&M for 3-4 years
HRC project presented 25% - 40% cost saving
(Faster too?)
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Currently frozen
Client went into liquidation
All activities on hold
But discussions now restarting
Project Status
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Technology Applicability in France
Closing Comments (URS)1. A great, “text book” reductive dechlorination case
study
2. HRC worked very well – it has a place in the remedial tool kit
3. Would reach for this technology where machinery is impractical for reasons of noise and space, fouling (e.g. sparging, drip-feed donors) or wash-out / subsidence concerns, (and in low-permeability formations - Regenesis).
4. Also valuable where on-going operation is not attractive – ‘one-off’ field installation provides maintenance-free remediation for several years
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Closing Statistics This was the first HRC application in France
Also the first full scale reductive dechlorination project in France?
URS have completed approx. 30 HRC projects worldwide out of more than 100 projects using Regenesis products
Total worldwide HRC projects is > 1.500 – HRC is the most widely used electron donor in the world
Largest URS HRC project (currently underway) is 81.500 kg in US – >ten times larger (presented project is ca. 7.000 kg)
URS therefore offer significant corporate experience with this technology in France, Europe, and internationally
Regenesis provide free technical support and project assistance
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For More Information:
URS Corporation (Paris)
Dr. Richard Sumner +33 (0)1 55 69 20 [email protected]
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Regenesis Ltd. (UK)Dr. Jeremy Birnstingl+44 (0)1225 722 [email protected]
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