Solvent Extraction 1
Solvent extraction does not destroy hazardous contaminants, but is a means of separating those contaminants from soils, sludges, and sediments, thereby reducing the volume of the hazardous material that must be treated. Generally it is used as one in a series of unit operations, and can reduce the overall cost for managing a particular site. It is applicable to organic contaminants and is generally not used for treating inorganic compounds and metals [1, p. 64]. 2 The technology generally uses an organic chemical as a solvent [2, p. 30], and differs from soil washing, which generally uses water or water with wash improving additives. Commercial-scale units are in operation. There is no clear solvent extraction technology leader because of the solvent employed, type of equipment used, or mode of operation. The final determination of the lowest cost/best performance alternative will be more site-specific than process dominated. Vendors should be contacted to determine the availability of a unit for a particular site. This chapter provides information on the technology applicability, the types of residuals produced, the latest performance data, site requirements, the status of the technology, and sources for further information.