| Abstract |
Solidification/stabilization (S/S) is an established technology that has been used for almost 20 years to treat a variety of wastes at Superfund remedial sites throughout the country. Historically, S/S has been one of the top five source control treatment technologies used at Superfund remedial sites. To provide interested stakeholders such as project managers, technology service providers, consulting engineers, site owners, and the general public with the most recent information about S/S applications at Superfund sites, as well as information about trends in use, specific types of applications, and cost, the U.S. Environmental Protection Agency (EPA) performed a review and analysis of S/S applications and prepared this summary. Highlights of S/S use at Superfund remedial sites include: Trends in Use - S/S is one of the top five source control treatment technologies used at Superfund remedial sites, having been used at more than 160 sites since FY 1982. The frequency with which S/S was selected as a remedy increased during the late 1980s and early 1990s, reaching a peak in FY 1992, and then generally decreasing through FY 1998. Project Status - Many of the S/S projects (62 percent) have been completed, with an estimated 21 percent in the predesign/design stage. Overall, completed S/S projects represent 30 percent of all completed projects in which treatment technologies have been used for source control. In addition, the average operational time for S/S projects was 1.1 months, which is shorter than other technologies such as soil vapor extraction, land treatment, and composting. Types of Applications - A majority of S/S projects at Superfund remedial sites are ex situ applications where inorganic binders and additives were used to treat metal-containing waste. Organic binders were used for specialized waste such as radioactive wastes and those containing specific hazardous organic compounds. S/S was used to treat wastes containing only organics for a small number
(6 percent) of the projects. Performance - Most performance testing for S/S waste products is conducted after curing is completed, and only limited data are available on long-term performance of S/S at Superfund remedial sites. Available performance data for metals for these projects showed that S/S met the established performance goals. Only limited data were available on organics; however, S/S met the established performance goals for several projects. Cost - Information about the cost of using S/S to treat wastes at Superfund remedial sites was available for 29 completed projects. The total cost ranged from $75,000 to $16 million. The average cost per cubic yard for these S/S projects was $264, including two projects with relatively high costs (approximately $1,200 per cubic yard each). Excluding those two projects, the average cost per cubic yard for S/S was $194. |
