Description:

Confined disposal facilities (CDFs) are engineered structure enclosed by dikes and designed to retain dredged materials. A CDF may have a large cell for material disposal, and adjoining cells for retention and decantation of turbid, supernatant water. A variety of linings have been used to prevent seepage through the dike walls. The most effective are clay or bentonite-cement slurries, but sand, soil, and sediment linings have also been used.

Location and design are two important CDF consideration. Terms to consider in the location of a CDF are the physical aspects (size, proximity to a navigable waterway), the design/construction (geology/hydrology), and the environmental (current use of the area, environmental value, and environmental effects). The primary goal of a CDF design is minimization of contaminant loss. Caps are the most effective way to minimize contaminant loss from CDFs, but selection of proper liner material is also an important control on CDFs. Finally, CDFs require continuous monitoring to ensure structural integrity.

Operation and maintenance duration lasts as long as the life of the facility.

Synonyms:

Applicability:

Limitations:

• Generation of fugitive emissions may be a problem during operations.
• The distance from the contaminated site to the nearest disposal facility with the required permit(s) will affect cost.
• Depth and composition of the media requiring excavation must be considered.
• Transportation of the soil through populated areas may affect community acceptability.
• Disposal options for certain waste (e.g., mixed waste or transuranic waste) may be limited. There is currently only one licensed disposal facility for radioactive and mixed waste in the United States.
• Contaminants can potentially migrate from CDF from several pathways, including effluent discharge to surface water, rainfall surface runoff, leachate into ground water, volatilization to the atmosphere, and dike uptake.
• CDFs can develop odor problems as well as mosquito and insect problems without proper design and maintenance.

Data Needs:

The type of contaminant and its concentration will impact off-site disposal requirements. Soil characterization as dictated by land disposal restrictions (LDRs) are required. Most hazardous wastes must be treated to meet either RCRA or non-RCRA treatment standards prior to land disposal. Radioactive wastes would have to meet disposal facility waste form requirements based on waste classification.

Performance Data:

The rate of excavation depends on a number of factors, including the number of loaders and trucks operating. The excavation of 18,200 metric tons (20,000 tons) of contaminated soil would typically require about 2 months. Disposal of the contaminated media is dependent upon the availability of adequate containers to transport the hazardous waste to a permitted facility.

CERCLA includes a statutory preference for treatment of contaminants, and excavation and off-site disposal is now less acceptable than in the past. The disposal of hazardous wastes is governed by RCRA (40 CFR Parts 261-265), and the U.S. Department of Transportation (DOT) regulates the transport of hazardous materials (49 CFR Parts 172-179, 49 CFR Part 1387, and DOT-E 8876).

DOE has demonstrated a cryogenic retrieval of buried waste system, which uses liquid nitrogen (LN2) to freeze soil and buried waste to reduce the spread of contamination while the buried material is retrieved with a series of remotely operated tools. Other excavation/retrieval systems that DOE is currently developing include a remote excavation system, a hydraulic impact end effector, and a high pressure waterjet dislodging and conveyance end effector using confined sluicing.

Cost:

Additional cost information can be found in the Hazardous, Toxic, and Radioactive Wastes (HTRW) Historical Cost Analysis System (HCAS) developed by Environmental Historical Cost Committee of Interagency Cost Estimation Group.

References:

Innovative Remediation Technologies:  Field Scale Demonstration Project in North America, 2nd Edition

Abstracts of Remediation Case Studies, Volume 4,  June, 2000, EPA 542-R-00-006

Guide to Documenting and Managing Cost and Performance Information for Remediation Projects - Revised Version, October, 1998, EPA 542-B-98-007

DOE, 1995. Technology Catalogue, Second Edition, Office of Environmental Management and Office of Technology Development, DOE/EM-0235.

EPA, 1991. Survey of Materials-Handling Technologies Used at Hazardous Waste Sites, EPA, ORD, Washington, DC, EPA/540/2-91/010.

EPA, 1992. McColl Superfund Site Demonstration of a Trial Excavation, EPA RREL, series include Technology Evaluation EPA/S40/R-92/015, PB92-226448; Applications Analysis, EPA/540/AR-92/015; and Technology Demonstration. Summary, EPA/540/SR/-92/015.

EPA, 1997. Best Management Practices (BMPs) for Soil Treatment Technologies: Suggested Operational Guidelines to Prevent Cross-media Transfer of Contaminants During Clean-UP Activities, EPA OSWER, EPA/530/R-97/007.

• EPA Demo: Carter Industrial, MI; Shaver's Farm, GA; Hopkinsville, KY
• EPA Demo:IN, MI, OH, SD, VA, WI
• DOE Integrated Demo: (1,2) Chemical and Mixed Waste Landfills, Albuquerque, NM; (3) Mixed Waste Landfill at Kirkland AFB, NM
• DOE Integrated Demo: Fernald Environmental Project Cincinnati, OH

General FRTR Agency Contacts

Government Web Sites

Non Government Web Sites

A list of vendors offering Soil Excavation, Retrieval, and Off-Site Disposal Treatment is available from  EPA REACH IT which combines information from three established EPA databases, the Vendor Information System for Innovative Treatment Technologies (VISITT), the Vendor Field Analytical and Characterization Technologies System (Vendor FACTS), and the Innovative Treatment Technologies (ITT), to give users access to comprehensive information about treatment and characterization technologies and their applications.

Government Disclaimer

Hazard Analysis