Technology:
Electrokinetics
- Pilot-scale testing was conducted in two adjacent treatment cells one for arsenic extraction and one for arsenic stabilization each measuring 30 ft long by 20 ft wide by 31 ft deep (18,600 ft3)
- Each treatment cell had three anodes spaced 10 feet apart and one cathode located 30 feet from the middle anode; the cathode was made of carbon steel and inserted to a depth of 31 feet
- In the first cell, a depolarizing agent was pumped in at the cathode to create a neutral to slightly basic catholyte
- In the second cell, proprietary reactive anodes were used to inject an arsenic-binding compound into the soil mass
- The first cell (extraction) required 80 kW-hr per yd3; the second cell (stabilization) 74 kW-hr per yd3; for each cell, the pH was 5 and moisture content was 25%
- Prior to the pilot- scale tests, bench scale studies were conducted using soil samples from several substation sites located in the southeastern U.S.
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Cleanup Authority:
Not identified
Site Contact:
Not identified | Regulatory Authority:
Not Identified |
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Contaminants:
Arsenic
- Concentrations ranged from 1 - 1,400 mg/kg |
Waste Source:
Herbicide use |
Type/Quantity of Media Treated:
Soil
- Silty sands without heavy clay
- Soil properties include pH of 5 and hydraulic conductivity of 6 x 10-5 cm/sec |
Purpose/Significance of Application:
First field demonstration of electrokinetic remediation in the U. S. by Electrokinetics, Inc. |
Regulatory Requirements/Cleanup Goals:
- Assess the performance of extraction and stabilization systems, and determine which configuration would yield the best results for extracting arsenic and preventing off-site migration |
Results:
- Bench-scale test results showed that >99% of arsenic was extracted; tests of arsenic-binding compounds showed that soil passed both the TCLP and SPLP leachability tests
- A final report for the pilot-scale demonstration had not yet been submitted, and performance results are not available for release to the public
- Results are expected to be available in the first quarter of 2000 |
Cost Factors:
- Cost data are not yet available for release to the public; these are expected to be available in the first quarter of 2000 |
Description:
A large southern U.S. power company performed bench- and pilot-scale studies of electrokinetic extraction and electrokinetic stabilization for selected arsenic contaminated sites. After extensive analysis of both the results of bench-scale studies on representative soils and site conditions at several substations, one active power substation site (confidential location) was selected for pilot-scale electrokinetic treatment. Both electrokinetic extraction and electrokinetic stabilization configurations were explored at this site.
The pilot scale demonstration was performed using one treatment cell for arsenic extraction, that used a depolarizing agent, and one cell for arsenic stabilization, that used proprietary reactive anodes. Results from the bench-scale tests showed extraction of >99% of the arsenic from the soil, and that soil passed both TCLP and SPLP leachability tests. Results from the pilot-scale tests are not yet publicly-available, but are expected to be made available in the first quarter of 2000. |
