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Crab Orchard Site 36
Project Information
- Project Location:
- Marion, IL
- Approx Contract:
- $4,000,000
- Status:
- Completed
- Structure Type:
- Government
References
- Client:
- U. S. Department of the Interior, Bureau of Reclamation
Scope Of Work
The Site 36-Miscellaneous Areas Operable Unit Remediation Project, involved the closure of a 21-acre Wastewater Treatment Plant (WWTP) located at the Crab Orchard National Wildlife Refuge in Marion, Illinois. The WWTP was constructed as part of the Illinois Ordnance Plant (IOP) in the 1940s and was operated continuously until recently. The site covered about 50 acres and included both recently used treatment facilities and others that had not been used for some time, plus adjacent ground and drainage channels.
For years during weapons production at the facility, upstream industrial processes produced wastes that contained PCBs and heavy metals. The remediation scope of work included the removal of all contaminated soils, sludge, and sediments, as well as the demolition and removal all WWTP lagoons and structures.
Pangea self-performed all significant work on this project. Pangea carefully planned the sequence of work necessary to complete the fieldwork in the initial four-month period. The initial scope of work included the following:
Removal and dewatering of sludge from the anaerobic digester, cleaning and testing the digester, and disposing of approximately 990 CY of the sludge. PCB concentrations in the sludge are > 50 milligrams per kilogram (mg/kg) (dry weight) and the sludge was disposed of in a chemical waste landfill in accordance with 40 CFR 761.
Removal and dewatering of approximately 350 CY of sludge from the treatment plant. The dewatered sludge had PCB concentrations < 50 mg/kg and was disposed of in an offsite landfill permitted under Subtitle D of RCRA ("Subtitle D landfill").
Demolition of the wastewater treatment plant and disposal of the waste concrete materials in a Subtitle D landfill.
On-site treatment of approximately 690,000 gallons of water to meet State of Illinois General Use Surface Water Quality Standards and discharge to a nearby stream under the facility’s NPDES permit.
Removal and dewatering of approximately 1750 CY of sludge from the East Pond and disposal in a chemical waste landfill.
Removal and dewatering of approximately 11,000 CY of sludge from the Primary and Secondary lagoons and disposal in a Subtitle D landfill.
Site restoration of approximately 24 acres, including re-grading, topsoil replacement, and re-establishment of vegetation.
As the project progressed, it was discovered that substantially increased volumes of PCB contaminated sediments and soils were present on the site. The final volume of contaminated sludge, sediments, and soils removed from the site totaled over 30,000 cubic yards. In addition, approximately 350 cubic yards of soil contaminated with cadmium were excavated and transported for disposal. The project performance period was extended by approximately six months to accommodate the expansion of work scope.
