Remediation of DNAPL pools using dense brine barrier strategies

Although dense nonaqueous phase liquid (DNAPL) pools are an important sourc e of groundwater contamination, little experimental data have been generate d to develop a mature level of understanding of the problem, and few strate gies specifically aimed at remediation have been advanced. We discuss the d ominant importance of these features in subsurface systems, present novel t wo- and three-dimensional heterogeneous experimental systems, and show resu lts from two evolving strategies for remediating DNAPL pools. These strateg ies involve the joint use of a dense brine barrier and controlled mobilizat ion of trapped DNAPL using small-volume surfactant flushes. These experimen ts demonstrate a controlled, substantial reduction of entrapped DNAPL in bo th two- and three-dimensional heterogeneous domains, using less than a sing le pore volume of flushing solution in some cases.