Efficient, near-complete removal of DNAPL from three-dimensional, heterogeneous porous media using a novel combination of treatment technologies.

Remediation of porous media containing an entrapped dense nonaqueous phase liquid (DNAPL) is extremely difficult due to the heterogeneity and three-dimensional spatial nature of typical natural systems. A novel treatment technology based on surfactant- and gravity-induced mobilization, dense brine containment and collection, and a vapor-phase extraction polishing step is proposed as a means to remediate such systems. Laboratory experiments are performed using the suggested methodology applied to three-dimensional, heterogeneous systems, which are packed based upon a realization from a correlated random field. Entrapped DNAPL is effectively removed as a result of each component of the technology. Following vapor extraction, less than 1% of the original DNAPL mass remained in the system. While these results are very promising, several open issues must be resolved before this technology can be considered mature; both the investigation of some of these issues and a summary of remaining needs are addressed.