Superfund sites cleanup process

The dehalogenation process has been approved by the EPA s Office of Toxic Substances for PCB treatment and has been experimentally implemented for the cleanup of PCB-contaminated soil at the following three Superfund sites Wide Beach in Erie County, New York (1985) Re-Solve in Massachusetts (1987) and Sol Lynn in Texas (1988). The glycolate process has been used to successfully treat contaminant concentrations of PCBs from less than 2 ppm to reportedly as high as 45,000 ppm. Using this technology, Helland et al. (1995) investigated reductive dechlorination of carbon tetrachloride with elemental iron and found that the rate of dechlorination to chloroform and methylene chloride was a fast first-order process. 

The National Priority List (NPL) is part of the Superfund cleanup process and is updated periodically. Sites are listed on the NPL upon completion of a hazard ranking, public solicitation of comments about the proposed site, and after all comments have been addressed. 

Terra-Vac, Inc., developed the In-Situ Vacuum Extraction process, which removes volatile organic constituents (VOCs) from the unsaturated zone of soils through extraction wells. The extracted gases and water proceed to a vapor-liquid separator and an emission control system. The process has been employed at over 60 sites. Four case studies, including three Superfund sites, have been documented. The process represents a viable technology to fully remediate sites contaminated with volatile organics. Considerations for use include contaminent volatility, site-specific cleanup level, and soil properties. The process works well with most soil types. The air-filled porosity of a soil is an important criterion to indicate whether vacuum extraction will work. Soils with low permeability but with... 

General Electric (GE) Corporation produced polychlorinated biphenyls (PCBs) at its plants in Eort Edward and Hudson Falls, New York, for use as dielectrics and coolant fluids in transformers, capacitors, and electric motors. From 1947 through 1977, they discharged the runoff from this process into the Hudson River. In 1983, theU.S. Enviromnental Protection Agency declared 200 miles of the Hudson River a superfund site, and sought to develop a cleanup and remediation plan to remove the PCBs that contaminated the sediment at the bottom of the river. Phase 1 cleanup was completed in 2009, at a cost to GE of 460,000,000. A projected Phase 2 effort will be even larger and more expensive (Highlight 1.3). 

In some applications, the waste material may directly contain dioxins and furans, or it may contain halogens that could lead to the formation of dioxins and furans. Many of the U.S. Superfund cleanup sites contain soil that has been contaminated with halogenated compounds. One common method to clean the soil is to process it through an incinerator which reduces the contaminants to trace levels (see Chapter 8). 

In many cases, OEC may also increase the revenue for waste processors. They may be able to treat waste that they were previously unable to process. This might include things like sewage sludge and other types of low-heating-value, high-moisture-content wastes. At Superfund cleanup sites, the waste processor can usually increase profits by cleaning up the contaminated waste faster than scheduled. Examples of this have already been discussed. 

The opposition to the use of incineration is described in detail in a prior NRC report (NRC, 2002). Reasons for it include the perceived instability of the process, the potential for explosion, and the potential for unplanned releases of undesirable compounds. This public opposition to incineration is also evident in the U.S. Environmental Protection Agency s Superfund program for cleanup of hazardous waste sites, where both on-site and off-site incineration were selected less frequently as treatment technologies as the years passed (EPA, 2004). For example, on-site incineration was selected four, seven, six, and four times in 1987, 1988, 1989, and 1990, respectively, for source control for remedial... 

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