Field test of cyclodextrin for enhanced in-situ flushing of multiple-component immiscible organic liquid contamination: Comparison to water flushing

A pilot-scale field experiment was conducted to compare the remediation effectiveness of an enhanced-solubilization technique to that of water flushing for removal of multicomponent nonaqueous-phase organic liquid (NAPL) contaminants from a phreatic aquifer. This innovative remediation technique uses cyclodextrin, a sugar (glucose)-based molecule, to enhance the apparent aqueous solubility of organic contaminants. The cyclodextrin solution significantly increased not only the apparent solubility for several target contaminants, but also the rate of dissolution. As a result of these effects, the time required for cleanup of NAPL contamination at this field site may be greatly reduced by using cyclodextrin-enhanced flushing. For example, it was estimated that more than 70,000 pore volumes of water flushing would be required to remove the undecane mass that was removed in the 8-pore volume cyclodextrin flush, and for trichloroethene, which exhibited the smallest solubility enhancement, about 350 pore volumes of water flushing would be required.