Non-aqueous phase liquid (NAPL) spills in the subsurface are considered the single most important factor limiting remediation of organic-contaminated sites at military and industrial sites. The generally limited performance of conventional groundwater pump-and-treat systems has led to consideration of chemically enhanced-flushing methods, such as cyclodextrin enhanced flushing (CDEF). Cyclodextrins are non-toxic, modified sugars that form complexes with hydrophobic pollutants such as trichloroethylene (TCE). Because of its non-toxicity, CDEF technology is an attractive alternative to other chemical flushing agents, such as many surfactants or cosolvent formulations.

Cyclodextrin-enhanced in-situ flushing of contaminated porous media generally begins with the injection of a water-based cyclodextrin solution. This solution is flushed through the contaminated aquifer and then extracted. Conventional injection and extraction wells can be used to control the flowfield of the flushing solution. This application scheme is in principle similar to conventional pump-and-treat systems, but due to the advantageous solubility enhancing properties of the cyclodextrin solution, mass removal rates are faster and consequently remediation times should be shorter.

Funded by ESTCP, Dr. Boving and his team of students and collaborators conducted a full-scale demonstration of CDEF technology demonstration in summer 2002. The final report and a cost and performance report can be downloaded in .pdf format.

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