CYCLODEXTRIN-ENHANCED IN-SITU FLUSHING OF MULTIPLE-COMPONENT IMMISCIBLE ORGANIC LIQUID CONTAMINATION AT THE FIELD-SCALE - MASS REMOVAL EFFECTIVENESS

The feasibility of ''enhanced-solubility'' remediation technologies, d esigned to enhance the removal of nonaqueous-phase organic liquids (NA PLs) from the subsurface, must be tested at the field scale. Herein ar e reported the results of an experiment designed to evaluate the effec tiveness of a cyclodextrin(sugar) solution for enhanced-solubilization removal of a multicomponent NAPL from an aquifer. This effort is the first field test of this innovative technology, termed a ''complexing sugar flush'' (CSF). The saturated zone within an enclosed cell was fl ushed with 8 pore volumes of a 10 wt % cyclodextrin solution. The cycl odextrin solution increased the aqueous concentrations of all the targ et contaminants to values from about 100 to more than 20 000 times the concentrations obtained during a water flush conducted immediately pr ior to the CSF. The degree of solubility enhancement was greater for t he more-hydrophobic contaminants. Conversely, the relative mass remova l was greater for the less-hydrophobic compounds due to their generall y higher apparent solubilities, which effected a significant reduction in the initial mass during the relatively short experiment. The avera ge reduction in soil-phase concentrations for the target contaminants was 41%. This mass-removal percentage corresponds well to the results- of partitioning-tracer tests, which indicated a 44% reduction in the a verage NAPL saturation.