More than a year ago, the U.S. Department of Energy's Office of Environmental Management established five focus areas for remediation and waste management. Now, the research and development activities of DOE's Office of Technology Development are directed at five areas of primary concern and three specializations relevant to all five focus areas. Initiatives interviewed Jaffer Mohiuddin, the Office of Technology Development's program manager for the landfill stabilization focus area, on April 14, 1995.

The primary goals of the landfill stabilization focus area are to manage the environmental contamination caused by DOE's past waste disposal practices and improve the department's current waste management practices.

It is estimated that DOE's landfills contain three million cubic meters of buried wastes that include construction and demolition materials, laboratory equipment, hand tools, greases, paper, rags, and plastic bags. The waste is buried on pads or in trenches, sumps, ponds, pits, cribs, heaps and piles, auger holes, caissons, and sanitary landfills.

Approximately half the waste was disposed of before 1970 when regulations permitted transuranic, low-level radioactive, and hazardous wastes to be mixed. The wastes were either disposed of directly or in containers such as steel drums, wooden boxes, and cardboard cartons. According to Mohiuddin, a study found that some of the containers had breached, contaminating large volumes of surrounding soil with radionuclides, polychlorinated biphenyls, heavy metals, organic solvents, reactive compounds, and other chemicals. "We have so many specific chemicals involved that we haven't been able to identify all of them," Mohiuddin explains. "This study was done in the late 70s, so it is safe to presume that a lot more drums and barrels have deteriorated enough since then to cause concern for the environment."

The landfill stabilization focus area works in several technical areas: assessment; retrieval; containment and stabilization; and treatment and disposal.

Assessment

There are two types of assessments: site and waste. Site assessment involves creating a site contamination map that shows the location of buried objects such as drums. It also includes determining the degree and extent of soil contamination. In the past, boring, drilling, and excavation have been used to assess sites, but recent emphasis has been on non-invasive methods for characterizing radioactive and mixed waste contaminated sites. After a site has been characterized, waste assessment is done to determine the types and concentrations of contamination found there. As with site assessment, the landfill stabilization focus area is working on developing and demonstrating non-invasive methods for characterizing waste rather than excavating samples of waste and media for analysis off site.

Retrieval

After assessment, the waste and surrounding soil may be excavated for treatment or disposal. Although conventional drilling and excavation methods have been used to retrieve waste in the past, the landfill stabilization focus area is working with OTD's robotics program (see Initiatives, August 1994) to develop remote retrieval capabilities.

Dig-face characterization and the contamination control unit are technologies that will be used to assist with retrieval.

Containment and stabilization

Containment refers to creating barriers around what is in the landfill so it doesn't leak out and damage the groundwater and other elements of the environment. Stabilization means taking steps to prevent airborne emissions during waste retrieval and changing the physical, chemical, or toxicological properties of contaminants in-situ to reduce the risk to human health or the environment.

Mohiuddin says, "In the short-term, we will be placing more emphasis on containment and stabilization. The reason is the cost. Containment and stabilization are a lot cheaper than retrieval and treatment." For waste containment, the landfill stabilization focus area is looking at surface caps. Mohiuddin explains that surface caps are, "... made of materials that have long-term integrity that rain water and other sources of water cannot penetrate." In addition, the landfill stabilization focus area is working on a system to ensure the integrity of barriers placed around buried waste.

Treatment and disposal

If waste and contaminated soils are excavated, they have to be treated. They may be treated and disposed of at the same site or taken to another site. The landfill and mixed waste focus areas are working together on several treatment technologies. Minimum Additive Waste Stabilization--or MAWS--is a technology being developed to reduce the amount of waste that must be disposed of after treatment.

Stakeholder involvement

The landfill stabilization focus area and its predecessor programs have been working to involve stakeholders such as the Western Governors' Association and the Federal Advisory Committee to Develop On-Site Innovative Technologies (DOIT). The focus area has also sponsored seminars, workshops, and public meetings such as the open house held in February at Idaho State University in Pocatello. The purpose of the event was to explain the Radiological and Hazardous Materials Measurement System, a system being developed to evaluate the contents of up to four drums of waste per hour without opening the drum. There are more than 100,000 drums of waste at DOE's Idaho site that must be evaluated before they can be shipped for long-term storage. In an interview with KIDK News 3, Ellie Hamilton, a local citizen who attended the open house summed up the importance of stakeholder involvement saying, "If we don't get involved as private citizens, then we have no right to complain about what is done or not done ... I think that there are a lot of good things to come from nuclear energy and radioactive isotopes, so I don't want to see all things connected with radioactivity immediately condemned just because they are radioactive and we don't understand them so well."

On July 23-24, the landfill stabilization focus area will hold a larger meeting that will be open to the public, industry, regulators, and other people in DOE. The workshop will also include an exposition of technologies being developed within the landfill stabilization focus area. The workshop will be held in Idaho Falls, Idaho. Contact Kevin Kostelnik of Lockheed Idaho Technologies Company, (208) 526-9642, for more information.

Focus area management

DOE's Savannah River Operations Office has been selected as the lead organization and implementation team for the landfill stabilization focus area. As with other focus areas, landfill stabilization activities will be coordinated by representatives from DOE's Offices of Environmental Restoration, Waste Management, and Technology Development in consultation with the Site Technology Coordination Groups (see Initiatives, April 1995).

If you are developing a technology that might be useful to DOE's landfill focus area, contact Jim Brown at Savannah River, (803) 725-2760; Jaffer Mohiuddin of the Office of Technology Development, (301) 903-7965; Paul Zielinski of the Office of Environmental Restoration, (301) 903-7645; or David Mark of the Office of Waste Management, (301) 903-7132.

Photo by Judy Schwab