Technology:
Soil Washing Materials Handling - Selective excavation of metals-contaminated soil using visual inspection, confirmed using on-site X-ray fluorescence Soil Washing System - Four components - screening, separation, froth flotation, sludge management; rated feed capacity of 25 tons/hour - Screening - multiple screens; coarse screen (>8 inches) and process oversize (>2 inches); wet screening of <2 inch materials - Separation - hydroclones separate coarse and fine-grained materials - Froth flotation - air flotation treatment units - Sludge management - overflow from hydroclones sent through clarifier, sludge thickener, filter press; filter cake disposed off site; water reused for wet screening
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Cleanup Authority:
CERCLA
- ROD Date: 9/28/90 - PRP Lead
SIC Code:
4953 (Sanitary Services,
Refuse Systems) | Point of Contact:
John Gorin
Remedial Project Manager
U.S. EPA Region 2
26 Federal Plaza
New York, NY
(202) 264-7592 |
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Contaminants:
Metals - Beryllium, chromium, copper, nickel, zinc, lead, mercury - Highest metals concentrations in sediments - chromium (8,010 mg/kg), copper (9,070 mg/kg), mercury (100 mg/kg) - Highest metals concentration in sludge - chromium (11,300 mg/kg), copper (16,300 mg/kg), lead (389 mg/kg), nickel (11,100 mg/kg) |
Waste Source:
Surface Impoundments/Lagoons |
Type/Quantity of Media Treated:
Soil and Sludge - 19,200 tons of soil and sludge - Moisture content of approximately 15% - pH of approximately 6.5 |
Purpose/Significance of Application:
EPA's first full-scale application of soil washing to remediate a Superfund site. Innovative on-site monitoring technique; selective excavation techniques, including use of X-ray fluorescence, to screen soil for cleanup. |
Regulatory Requirements/Cleanup Goals:
1990 ROD identified soil cleanup levels for 11 metals - Arsenic (190 mg/kg), beryllium (485 mg/kg), cadmium (107 mg/kg), chromium (483 mg/kg), copper (3,571 mg/kg), lead (500 mg/kg), mercury (1 mg/kg), nickel (1,935 mg/kg), selenium (4 mg/kg), silver (5 mg/kg), zinc (3,800 mg/kg) |
Results:
- Cleanup goals were met for all 11 metals - Cleanup goals were achieved in less than 4 months |
Cost Factors:
- Total cost of $7,700,000 (including off-site disposal cost) |
Description:
The King of Prussia (KOP) Technical Corporation Superfund site had been used as a waste recycling facility from 1971 to 1974. An estimated 15 million gallons of liquid industrial waste were processed in six lagoons. These activities resulted in soil and sludge contamination at the site. The primary constituents of concern were chromium (at levels up to 11,300 mg/kg), copper (at levels up to 16,300 mg/kg), and nickel (at levels up to 11,100 mg/kg). The ROD, signed in September 1990, specified complete excavation of soils, sediments, and sludges from these lagoons and use of contaminant extraction (soil washing) to achieve the specified soil cleanup levels for 11 metals.
The soil washing system at KOP was selected based on the results of a treatability study and data from a demonstration run using KOP soil at a full-scale unit in the Netherlands. The soil washing system was operated at KOP from June 1993 to October 1993. The system consisted of a series of hydroclones, conditioners, and froth flotation cells. Approximately 19,200 tons of contaminated soil and sludge were treated during this application. The soil washing system achieved the specified soil cleanup levels for all 11 metals, and the treated soil was used as backfill at the site. Of note for this full-scale cleanup was the use of selective excavation techniques to screen contaminated soil and sludge for treatment. Selective excavation was performed through visual examination confirmed using on-site X-ray fluorescence, and resulted in fewer tons of soil requiring treatment.
The total cost for this application was $7,700,000, including off-site disposal costs for the sludge cake. Selective excavation reduced the overall costs for the application by reducing the amount of soil requiring treatment by a factor of two. Further, the data from the demonstration run expedited the design schedule of the full-scale unit by more than a year. |
