Dense Non-Aqueous Phase Liquids (DNAPLs): Review of Emerging Characterization and Remediation Technologies

摘要

Because of the mounting interest from ITRC member states in addressing DNAPL contaminant problems, ITRC was asked for input on several sampling and analysis plans commissioned by the Interagency DNAPL Consortium (IDC) as part of its DNAPL demonstration project at Cape Canaveral Air Station in Florida. Initially formed in 1999 to review these documents, the ITRC DNAPL Work Team was expanded to address emerging issues in DNAPL characterization and remediation. The team has prepared this technology overview document to summarize recent developments in this field. The purpose of this document is to educate regulators and project managers about the DNAPL problem and to spotlight a selection of emerging characterization and remediation technologies for DNAPLs. Traditionally, sites with DNAPL were often dealt with through a ground water containment strategy whereby the recalcitrant source material and/or the resultant plume of dissolved contaminants are physically contained and monitored over the long term to keep them from migrating further. Emerging in situ technologies are now being developed that actively target these DNAPL sources for elimination or substantial reduction. DNAPL Source Characterization. Because the DNAPL source is targeted, additional characterization efforts, focused in the known or suspected source zone, are often needed to go beyond the conventional techniques typically used to delineate a dissolved plume. In addition to modifications of conventional soil and water sampling methods, innovative field characterization methods may in some cases reasonably provide higher reliability in the detection and quantification of DNAPL. Three general types of emerging DNAPL characterization technologies are presented in this document: geophysical techniques (noninstrusive to minimally intrusive), direct push technologies employing one or a variety of DNAPL screening/sampling devices; and in situ, large-volume chromatography using chemical tracers.