Technology:
Electrokinetics
- Demonstration system used 15 electrodes - three rows of electrodes positioned one meter apart, with each row consisting of five electrodes spaced every two meters
- Electrodes were installed 2.4 meters bgs for a total soil volume of 38.4 cubic meters
- An acidic solution was maintained at a pH of 4 - 5 in the electrode cells, and solution was removed for processing and recovery above-ground
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Results:
- In most soil layers, the system met the cleanup goal, however, in the most contaminated layer of soil (the interface between soil and concrete), the system did not meet the cleanup goal of 30 mg/kg of chromium in soil
- Electrokinetics removed 12% of the total chromium based on pre- and post-treated soil data, and only 1% based on total chromium recovered in the electrode solution
- During the demonstration, the water table dropped below design specifications and bentonite seals were used to maintain the electrode solution; this modification was projected to have decreased system performance by as much as 50 percent |
Cost Factors:
- The demonstration had a cost of $194,291, or $4,318/cubic yard, for vendor-supplied services
- It was projected that a full-scale system would have treatment costs of $90/cubic yard |
Description:
Alameda Point had a former aircraft rework facility plating shop that operated from 1942 to 1990. During plating operations, chromium leaked into the soil beneath the shop. The Navy, in coordination with the Bay Area Defense Conversion Action Team (BADCAT) Environmental Technology Partnership (ETP), conducted a demonstration of electrokinetics at this site. The BADCAT is a public-private partnership of several organizations in the San Francisco area, including the Bay Area Economic Forum, Bay Area Regional Technology Alliance, California EPA, San Francisco State University, EPA, and Navy.
Electrokinetic remediation was performed for four months using 38.4 cubic meters of soil. Treatment removed 12% of the total chromium based on pre- and post-treated soil data, and only 1% based on total chromium recovered in the electrode solution. In most soil layers, the system met the cleanup goal, however, in the most contaminated layer of soil (the interface between soil and concrete), the system did not meet the cleanup goal. The demonstration had a cost of $194,291, or $4,318/cubic yard, for vendor-supplied services. It was projected that a full-scale system would have treatment costs of $90/cubic yard |
