Review of Characterization and Remediation Technologies for NAPL's in Groundwater

The principal legislation dealing with contaminated sites in the United States was enacted in 1980. It dealt with abandoned hazardous waste dumps; since then additional legislation has been passed to deal with corrective action from releases at operating industrial facilities, leaking underground gasoline storage tanks, and redevelopment and renewal of central urban areas thought to be contaminated (i.e. the restoration of Brown fields). As each of these programs has been implemented, the engineering community has worked with technology developers to utilize new technologies to solve these problems. This paper describes some of the major techniques and approaches that have evolved over the last 25 years and the information resources that are now available to those in other countries facing these contaminated soil and groundwater problems for the first time. This paper discusses the current technologies being used, primarily with data from the U.S. Superfund program, and then, with particular emphasis on the detection and clean up of dense non-aqueous phase liquids (DNAPL’s), reviews the latest groundwater monitoring and assessment approaches as well as remediation technologies. Finally, there is a brief discussion of new and emerging approaches being explored in the U.S.