Implementation of a
Nanoscale Zero Valent Iron
Remediation Demonstration
Keith W. Henn, P.G.,
Tetra Tech NUS, Inc.
Dan Waddill, PE, PhD.
NAVFAC EFD South
U.S. EPA Workshop on Nanotechnology for Site Remediation
October 20, 2005
Tetra Tech NUS, Inc.
Overview of presentation
Ø Overview of Nanoscale Iron
Ø Full Scale Pilot Study, NAS Jacksonville
Ø Summary and Conclusions
2
October 2005
1
Nanoscale Zero Valent Iron
Dehalogenation Schematic
C2 Cl3
Other Contaminants
•Chlorinated VOCs
•Nitrates
•Metals (e.g, Cr, As)
•Chlorinated Pesticides
C2 H6 + 3Cl-
eFe2+
Base metal
- Electron donor
Noble Metals:
- forms galvanic cells
- catalyze hydrogenation
~10-600 nm
Base Metal
Noble Metal
Fe 0
Pd
Source: modified after Lehigh University
MW-28
Site Background
N
MW-33
Ø Small area (1050 sq ft)
MW-32
MW-30
MW-37
Ø Utility corridor
MW-8
MW-29
Ø Geology
MW-34
• Silty to fine sand from
0 to 24 feet bgs
MW-31
MW-36
• Dense clay from 24 to
54 ft bgs
MW-38
MW-01
Ø
Hydrogeology
• Flow toward southeast
• Water table at 7 feet bgs
Groundwater flow
direction
• Hyd. Conduct. ~2 ft/day
0
4
5
10 15
MW-39
October 2005
2
Site Contamination
Summary
GW Flow
Hangar 1000, NAS Jacksonville
Maximum Total VOC
550 mg/kg in soil
80 mg/L in groundwater
Chemical oxidation
conducted in 2001
Full Scale Pilot Study Design
• Remedial Goal as defined in the Work Plan
– Reduce contaminant mass 40 to 50%
– Not expected to reach groundwater MCLs
– MNA anticipated as next step
• How much iron is needed?
–
–
–
–
Reaction Capactity (VOCs : Nano Fe) = ~1:5-10 by wt.
CVOC mass estimated: 42 to 125 lbs
Need an estimated 210 to 1250 lbs
Injected 300 lbs
• Two injection methods:
– Strategic DPT injections
– Recirculation Process
Source: U.S. Navy
6
October 2005
3
Tetra Tech NUS, Inc.
Recirculation Setup
7
October 2005
8
October 2005
Nanoscale Iron
– Polymer Supported
w/Palladium Catalyst
– No carbon substrate
4
Recirculation:
Hydraulic Results
•Keep iron in
source
•Good mixing
Before
•Good iron
distribution
(Dec 29th)
During
(Jan 21st )
After
(Jan 23rd)
Injections #1 and #2
October 2005
Chlorinated Ethene
150
Source Well
H10MW37
Molar Concentrations
Injections #1 and #2
VC
CIS-1,2-DCE
TCE
100
PCE
75
50
25
Chlorinated Ethane
0
4
/03 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 3/0 /04 /04 /04 /04 /04 /04 /04 /04 /04
/20 /02 1/15 1/28 2/10 2/23 3/07 3/20 4/02 4/15 4/28 5/11 5/24 6/06 6/19 7/02 7/15 7/28 8/10 8/2 9/05 9/18 0/01 0/14 0/27 1/09 1/22 2/05 2/18
12 01
0 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1 1
1
1
1
0
30
Molar Concentration (uM/L)
Molar Concentration (uM/L)
ETHENE+ETHANE
125
3
6
Date
Months
9
12
25
20
ETHENE+ETHANE
15
1,2-DCA
VC
10
1,1-DCE
CA
5
1,1-DCA
1,1,1-TCA
0
/03 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04
/20 /02 /15 /28 /10 /23 /07 /20 /02 /15 /28 /11 /24 /06 /19 /02 /15 /28 /10 /23 /05 /18 /01 /14 /27 /09 /22 /05 /18
12 01 01 01 02 02 03 03 04 04 04 05 05 06 06 07 07 07 08 08 09 09 10 10 10 11 11 12 12
0
3
6
Date
Months
9
12
5
Injections #1 and #2
Chlorinated Ethene
ETHENE+ETHANE
Source Well
H10MW34
Molar Concentrations
Molar Concentration (uM/L)
100
CIS-1,2-DCE
75
TCE
PCE
50
25
0
Chlorinated Ethane
Injections #1 and #2
VC
4
4
4
4 4
4
/03 /04 /0 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /0 /04 /04 /0 /04 /04 /0 /0 /04 /0
/20 /02 /15 /28 /10 /23 /07 /20 /02 /15 /28 /11 /24 /06 /19 /02 /15 /28 /10 /23 /05 /18 /01 /14 /27 /09 /22 /05 /18
12 01 01 01 02 02 03 03 04 04 04 05 05 06 06 07 07 07 08 08 09 09 10 10 10 11 11 12 12
0
20
3
6
Date
Months
ETHENE+ETHANE
18
12
1,2-DCA
16
Molar Concentration (uM/L)
9
VC
1,1-DCE
14
12
CA
1,1-DCA
10
1,1,1-TCA
8
6
4
2
0
/03 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04 /04
/20 /02 /15 /28 /10 /23 /07 /20 /02 /15 /28 /11 /24 /06 /19 /02 /15 /28 /10 /23 /05 /18 /01 /14 /27 /09 /22 /05 /18
12 01 01 01 02 02 03 03 04 04 04 05 05 06 06 07 07 07 08 08 09 09 10 10 10 11 11 12 12
0
3
6
Date
Months
9
12
Injections #1 and #2
Butane
5
Beta-Elimination
Pathway
4
Concentrations (mg/L)
6.6 mg/L
3
2
Acetylene, Butane, & Isobutane
0
Injections #1 and #2
12
/2
0/0
01 3
/0
5/0
01 4
/2
1/0
02 4
/0
6/0
02 4
/22
/0
03 4
/0
9/0
03 4
/25
/0
04 4
/10
/0
04 4
/26
/0
05 4
/12
/0
05 4
/28
/0
06 4
/1
3/0
06 4
/29
/0
07 4
/1
5/0
07 4
/3
1/0
08 4
/1
6/0
09 4
/0
1/0
09 4
/17
/0
10 4
/03
/0
10 4
/19
/0
11 4
/04
/04
11
/20
/0
12 4
/06
/0
12 4
/2
2/0
4
Injections #1 and #2
1
Acetylene
Time
0.2
Concentrations (mg/L)
3
2
0.1
1
0
12
/20
/0
01 3
/05
/04
01
/2
1/0
02 4
/0
6/0
02 4
/2
2/0
03 4
/09
/0
03 4
/2
5/0
04 4
/1
0/0
04 4
/2
6/0
05 4
/12
/0
05 4
/28
/0
06 4
/13
/04
06
/2
9/0
07 4
/1
5/0
07 4
/3
1/0
08 4
/16
/0
09 4
/0
1/0
09 4
/1
7/0
10 4
/0
3/0
10 4
/19
/0
11 4
/04
/0
11 4
/20
/0
12 4
/0
6/0
12 4
/2
2/0
01 4
/07
/05
0
0
3
6
Months
Time
9
12
12
/20
/0
01 3
/05
/0
01 4
/21
/0
02 4
/06
/04
02
/22
/0
03 4
/09
03 /04
/25
/0
04 4
/10
/0
04 4
/26
/04
05
/12
/0
05 4
/28
/0
06 4
/13
06 /04
/29
/0
07 4
/15
/0
07 4
/31
/04
08
/16
/0
09 4
/01
/0
09 4
/17
10 /04
/03
/0
10 4
/19
/0
11 4
/04
/04
11
/20
/0
12 4
/06
12 /04
/22
/04
Concentrations (mg/L)
Isobutane
Isobutane
4
0
3
6
Time
Months
9
12
6
Round 1
(baseline)
TCE isoconcentrations
13
October 2005
14
October 2005
Round 3
(after
inject)
TCE isoconcentrations
7
Round 11
(after
inject)
TCE isoconcentrations
15
October 2005
Injections #1 and #2
Dissolved Oxygen
3
Oxygen & ORP
2.5
Concentrations (mg/L)
Geochemistry
Results
2
1.5
1
0.5
0
Injections #1 and #2
Oxidation-Reduction Potential
250
4
4
/03 /04 /04 /04 /04 /04 /04
/04 /04 /04 /04 3/0 /04 /04 /04 /04
/04 /04 3/0 /04
/04 /04
/04 /04
/20 1/05 1/21 2/06 2/22 3/09 3/25 4/10 4/26 5/12 5/28 6/1 6/29 7/15 7/31 8/16 9/01 9/17 0/0 0/19 1/04 1/20 2/06 2/22
12
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
0
3
6
Time
Months
9
12
ORP (millivolts)
150
50
H10MW10
(upgradient well)
H10MW32
(source well)
-50
H10MW34
-150
H10MW37
-250
(source well)
H10MW38
(down grad. well)
H10MW39
(down grad. well)
12
/20
/0
01 3
/05
/0
01 4
/21
/0
02 4
/06
/0
02 4
/22
/04
03
/09
/0
03 4
/25
/0
04 4
/10
/0
04 4
/26
/0
05 4
/12
/0
05 4
/28
/0
06 4
/13
/04
06
/29
/0
07 4
/15
/0
07 4
/31
/0
08 4
/16
/04
09
/01
/0
09 4
/17
/0
10 4
/03
/0
10 4
/19
/0
11 4
/04
/0
11 4
/20
/0
12 4
/06
/0
12 4
/22
/04
-350
(source well)
0
3
6
Months
9
12
8
12
/2
0/0
01 3
/05
/0
01 4
/2
1/0
02 4
/06
/0
02 4
/2
2/0
03 4
/0
9/0
03 4
/2
5/0
04 4
/1
0/0
04 4
/26
/0
05 4
/1
2/0
05 4
/28
/0
06 4
/1
3/0
06 4
/2
9/0
07 4
/15
/0
07 4
/3
1/0
08 4
/16
/0
09 4
/0
1/0
09 4
/1
7/0
10 4
/03
/0
10 4
/1
9/0
11 4
/04
/04
11
/2
0/0
12 4
/06
/0
12 4
/22
/0
01 4
/0
7/0
5
Concentrations (ug/L)
12
/2
0/0
3
01
/0
5/0
01 4
/2
1/0
4
02
/0
6/0
02 4
/22
/04
03
/0
9/0
03 4
/25
/04
04
/1
0/0
04 4
/26
/04
05
/1
2/0
4
05
/2
8/0
06 4
/1
3/0
4
06
/2
9/0
07 4
/15
/04
07
/3
1/0
08 4
/16
/04
09
/0
1/0
09 4
/17
/04
10
/0
3/0
4
10
/1
9/0
11 4
/0
4/0
4
11
/2
0/0
12 4
/06
/04
12
/2
2/0
4
Concentrations (mg/L)
25
0
12
/2
0/0
01 3
/0
5/0
01 4
/21
/0
02 4
/06
/0
02 4
/22
/04
03
/0
9/0
03 4
/2
5/0
04 4
/10
/0
04 4
/26
/0
05 4
/12
/04
05
/2
8/0
06 4
/1
3/0
06 4
/29
/0
07 4
/15
/04
07
/3
1/0
08 4
/1
6/0
09 4
/01
/0
09 4
/17
/0
10 4
/03
/04
10
/1
9/0
11 4
/0
4/0
11 4
/20
/0
12 4
/06
/04
12
/2
2/0
4
Injections #1 and #2
0
3
Time
0
6
Months
Geochemistry
Results
Carbon Dioxide, Methane
& pH (stable from 6-7)
Injections #1 and #2
2500
3
6
Months
Concentrations (mg/L)
12
/20
/0
01 3
/05
/0
01 4
/21
/0
02 4
/06
/0
02 4
/22
/0
03 4
/09
/0
03 4
/25
/0
04 4
/10
/0
04 4
/26
/0
05 4
/12
/0
05 4
/28
/04
06
/13
/0
06 4
/29
/0
07 4
/15
/0
07 4
/31
/04
08
/16
/0
09 4
/01
/0
09 4
/17
/0
10 4
/03
/04
10
/19
/0
11 4
/04
/0
11 4
/20
/0
12 4
/06
/0
12 4
/22
/0
01 4
/07
/05
Geochemistry
Results
Dissolved Iron & Sulfate
3000
9
Concentrations (ug/L)
Injections #1 and #2
12000
15
10
5
9
Injections #1 and #2
0
0
3
2000
1000
500
Dissolved Iron
14000
10000
26,000 ug/L
8000
6000
4000
Sulfate
2000
0
3
6
Months
Time
6
Months
9
9
12
20
H10MW10
(upgradient well)
H10MW32
(source well)
H10MW34
(source well)
H10MW37
(source well)
H10MW38
(down grad. well)
0
H10MW39
(down grad. well)
12
250
Carbon Dioxide
200
150
100
Methane
50
12
4750 ug/L
Time
1500
H10MW10
(upgradient well)
H10MW32
(source well)
H10MW34
H10MW37
(source well)
(source well)
H10MW38
(down grad. well)
0
H10MW39
(down grad. well)
Time
12
9
Is there evidence for biological activity?
Ø qPCR analysis for Dehalococcoides (GC/ML)
conducted in 3 wells:
Well
Baseline
(GC/ML)
12 months after
injection
(GC/ML)
H10MW10
500 U
18
H10MW37
500 U
25 U
H10MW39
174
1.65
19
October 2005
Soil Sampling Summary
Percent change: Soil data before & after study
Soil Boring
H1K -03
H1K -31
H1K -31
H1K -34
H1K -35
H1K -36
H1K -38
Depth ( feet-bgs)
19'
8'
20'
20'
22'
20'
20'
16'
-
-50%
-93%
-100%
-92%
-
-
-99%
1,1,1-TCA
H1K -39
1,1-DCA
5%
-
-
-84%
-43%
-
-91%
46%
1,1-DCE
-
-36%
-
-
-77%
-
-97%
-
Methylene
chloride
-
-
-
-100%
-
-
-
-
PCE
-
-28%
-100%
-
-99%
-
-
-
TCE
-100%
141%
-96%
-100%
-100%
-100%
-100%
-
-
-
-
-
-
-
-
-
cis-1,2-DCE
267%
-
1026%
174%
11%
-
-71%
18%
Total % Change
11%
8%
92%
92%
75%
94%
88%
25%
Vinyl chloride
RED/Yellow - indicates DECREASE in concentration
BLUE/ Gray - indicated INCREASE in concentration
20
October 2005
10
Mass Reduction Summary
Ø Total Mass Reduction before & after study
Ø Soil mass
Ø Dissolved mass
Ø Sorbed mass
Maximum
Most Likely
Minimum
Pre-Injection
(Baseline)
Post-Injection
(after Round 11)
Pounds
destroyed
Percent
Difference
125 lbs
61 lbs
42 lbs
47 lbs
47 lbs
35 lbs
78
14
7
62%
23%
16%
RED/Yellow - indicates DECREASE in concentration
BLUE/ Gray - indicated INCREASE in concentration
21
October 2005
How much was it?
Ø Total Cost to Implement: $260K (2004)
• Iron injection costs: $112K
• Nanoscale iron: $37K (late 2003) *
• Today this cost would have been $5 to 14K
• Monitoring costs: $111K
Ø Comparable to other technologies today…
•
•
•
•
Nanoscale iron: $185K (2005)
Chemical Oxidation: $145K
Bioremediation $ 150K - $175K
Excavation: $385K – $485K
* Pound per pound is not a good comparison
22
October 2005
11
Summary
Ø Data suggests favorable results
• Significant TCE & 1,1,1-TCA reductions across the site
• Generation of daughter products
• cis-1,2 DCE, 1,1-DCE, 1,1-DCA
• very little VC
• Mass destruction evident
• Good mass balance in some wells
• Ethene & ethene conentrations increased up to 2 order (770%)
• Acetylene and light hydrocarbons increased up to 2 order
• Longevity of iron: 6 to 9 months
23
October 2005
Summary (cont.)
Ø Data suggests favorable results (cont.)
•
•
Plume extent was reduced (MW-33 & MW-36)
At or below GCTLs levels in MW-39 (downgradient well)
• Reduced mass flux from source
Ø Concentrations in the ‘core’ returned (expected)
•
Elevated concentations returned in source wells
(MW-08, MW-32, MW- 37)
Ø Mass reduced between 16 and 63 %
•
•
We met the 40-50% reduction goal (regulators)
To be included in the ROD for site
Ø Further reductions could have been achieved
(not needed to meet project goals)
24
October 2005
12
Is this the Silver Bullet ?
Ø It works…but not in
all cases.
– Quick…Not much to do (no nutrients,
no pH issues)
– Good for small sources…not for very large ones
– Bioremediation may work better in some
environments
– An emerging science that is making strides
– Treatment trains and ‘combinations’
25
October 2005
Tetra Tech NUS, Inc.
Thanks for attending
Keith Henn, PG
Phone: 412-921-8146
Email: hennk@ttnus.com
26
October 2005
13