Cyclodextrin enhanced in situ flushing of multiple-component immiscible organic liquid contamination at the field scale: Analysis of dissolution behavior

There is great interest in the potential use of solubility-enhancing agents for subsurface remediation of non-aqueous-phase organic liquid (NAPL) cont amination. Cyclodextrin was demonstrated to be effective for NAPL removal d uring a recent pilot-scale field study. The study provides an opportunity t o investigate the mechanisms controlling mass transfer between a multicompo nent NAPL and an enhanced-flushing agent solution at the field scale. A rel ationship is developed to describe enhanced dissolution of a multiple-compo nent NAPL and is used to analyze the field data. While NAPL dissolution beh avior was generally complex during the cyclodextrin flush, the initial peak and final effluent concentrations for most of the target contaminants were within a factor of 2 of the equilibrium values predicted using the ideal e nhanced-dissolution theory. This suggests that the dissolution of the multi component NAPL during the cyclodextrin flush may be approximately treated, at least for practical purposes, as an ideal, equilibrium process. It appea rs that the dissolution theory successfully predicted the observed behavior for this system. Thus, it may be useful for assisting in the planning, des ign, and evaluation of other enhanced-flushing applications involving multi component NAPL.