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Activated Metal Treatment System for Paints
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Field Demonstrations
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NASA's Activated Metal Treatment System (AMTS) has been demonstrated at multiple sites, including NASA's Marshall Space Flight Center, Cape Canaveral Air Force Station, and Badger Army Ammunition Plant. The Cape Canaveral and Badger demonstrations were conducted as part of the Department of Defense's (DoD's) Environmental Security Technology Certification Program (ESTCP). The objectives of these ESTCP projects were to
- Refine and demonstrate a safe, cost-effective, in-situ treatment method for the removal and destruction of polychlorinated biphenyls (PCBs) found on DoD structures,
- Formulate AMTS for various PCB-containing materials based on site-specific conditions,
- Demonstrate the effectiveness of AMTS on a wide range of actual contaminated structures at multiple sites,
- Develop appropriate on-site safety protocols for AMTS application, and
- Develop full-scale cost and performance reports for DoD facility end-users to employ when addressing PCBs found on existing structures.
Details on the ESTCP projects, as well as preliminary results, are provided below. Field work for these projects has been completed, with release of the final report anticipated later in 2009.
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| Cape Canaveral Air Station, FL |
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The Cape Canaveral demonstration was conducted at the facility's Space Launch Complex 19. At this location, PCB-laden paints were found in launch structures as well as the hanger building—referred to as the Vertical Integration Building (VIB, Figure 1). Dismantling of the VIB started in May 2007. Large structural components, including I-beams, panels, and doors, were removed from the site and transported to a nearby building for treatability testing. Analysis showed significant disparities between PCB concentrations within the three layers of paint from the structure surfaces, as well as between the different locations where the components were sampled. Baseline PCB concentrations in the various paint samples ranged from 3 to 14,000 milligrams per kilogram (mg/kg).
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Figure 1: Vertical Integration Building at
Cape Canaveral Air Station
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Figure 2: Application of AMTS
to
a Painted Beam
Figure 3: Sealant Sprayed on
Top of AMTS
Figure 4: Less Viscous AMTS Formula Being Spray-Applied to a Painted Panel
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AMTS was manufactured at the Cape Canaveral site by combining an activated metal with a solvent system and a thickening agent to form a paste. In this case, the activated metal consisted of a bimetal made from palladium and magnesium, and the solvent system consisted of various ratios of ethanol and limonene. The paste was applied using a hand trowel to the VIB structural components (Figure 2). A sealant, in the form of an aerosol spray, was applied over the paste to prevent the solvent component from drying out (Figure 3). Two different commercial-off-the-shelf sealants (a silicone and a vinyl polymer) were evaluated during this study. After treatment times ranging from one to several weeks, paint samples were removed from the structural components and tested for PCB content.
A less viscous AMTS formula was also manufactured and tested as part of the VIB demonstration. Whereas the AMTS paste mentioned above required hand application using a trowel, the alternate formula could be applied using a spray gun (Figure 4). This method proved to be a more efficient way of applying the product to many of the structural components at the site. As with the paste formula, a commercial-off-the-shelf sealant was sprayed on top of the alternative AMTS formula. Paint samples were removed from the components after varying treatment times and then tested for PCB content.
The AMTS technology involves two primary processes:
- the extraction of PCBs from the painted surface into the AMTS paste, and
- the subsequent degradation of the PCBs inside the AMTS paste.
To evaluate the amount of time for the extraction process alone, a non-active paste was tested at the Cape Canaveral site. The non-active paste had the same chemical formula as the active paste, except that no activated metals were added. In this manner, extraction rates of the AMTS could be measured independently of degradation rates.
Preliminary results from the Cape Canaveral demonstration are shown in Tables 1 and 2 below.
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Table 1: Preliminary Performance Data for ATMS during
Cape Canaveral Demonstration
(Test Results with Active Paste)
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| Location |
Starting Concentration (mg/kg) |
Finishing Concentration (mg/kg) |
% Removal |
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Week 1 |
| Panel 8 Sample 5 |
72.12 |
15.88 |
78% |
| Panel 8 Sample 6 |
65.24 |
15.8 |
76% |
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Week 2 |
| Panel 8 Sample 6 |
65.24 |
27.14 |
58% |
| Panel 8 Sample 7 |
69.55 |
23.63 |
66% |
Table 2: Preliminary Performance Data for Non-active Paste
during Cape Canaveral Demonstration
(Extraction Rates Alone-Not Degradation Rates) |
| Location |
Starting Concentration (mg/kg) |
Finishing Concentration (mg/kg) |
% Removal
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Week 1 |
| Panel 3 Sample 7 |
94.17 |
33.01 |
65% |
| Panel 3 Sample 8 |
102.47 |
30.64 |
70% |
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Week 2 |
| Panel 3 Sample 9 |
80.40 |
14.16 |
82% |
| Panel 3 Sample 10 |
88.59 |
13.94 |
84% |
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Week 3 |
| Panel 3 Sample 1 |
72.14 |
2.21 |
97% |
| Panel 3 Sample 2 |
65.70 |
1.61 |
98% |
| Panel 3 Sample 3 |
72.34 |
3.01 |
96% |
| Panel 3 Sample 4 |
71.00 |
3.11 |
96% |
| Panel 3 Sample 5 |
86.80 |
1.79 |
98% |
| Panel 3 Sample 6 |
85.82 |
1.61 |
98% |
| Panel 3 Sample 11 |
80.28 |
1.48 |
98% |
| Panel 3 Sample 12 |
74.02 |
1.63 |
98% |
| Badger Army Ammunition Plant, WI | |
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Figure 5: AMTS Testing at Badger
on Metal Surfaces (Press Equipment)
with PCB-laden Paints
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Figure 6: AMTS Testing at Badger
on a Concrete Structure
with PCB-laden Paints
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Unlike the Cape Canaveral site, PCB-laden paints at Badger were found on not only metal surfaces (Figure 5), but also on wood and concrete surfaces (Figure 6). PCB concentrations in paint samples from the facility ranged from 30 to 55,000 mg/kg. Similar to the Cape Canaveral demonstration, several different AMTS formulas (with a bimetal as the catalyst) were tested, as well as two different commercial-off-the-shelf sealants. AMTS was applied as a paste using a hand trowel in some test areas at Badger and as a less viscous formula using a liquid sprayer (i.e., paint gun) in other areas at the site.
Researchers discovered that the porous nature of the wood and concrete being tested at Badger caused the AMTS solvent to be absorbed into these substrates. As a result, the AMTS was less effective. To address this issue, researchers modified the formula to include an adsorbent, which served as a reservoir for the solvent. One of the most effective adsorbent materials was found to be cellulose pulp filler-the same material used in super-absorbing baby diapers
Although the field work has been completed at the Badger site, data is not yet available for this site. However, preliminary results have been positive. Initial results also indicate that AMTS is effective at temperatures below freezing (e.g., -6° Celsius and -10° Celsius). Additional details and results from this study will be available in the final ESTCP report (expected to be released later in 2009).
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