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

摘要

There is great interest in the potential use of solubility-enhancing agents for subsurface remediation of non-aqueousphase organic liquid (NAPL) contamination. Cyclodextrin was demonstrated to be effective for NAPL removal during a recentpilot-scale field study. The study provides an opportunity to investigate the mechanisms controlling mass transfer between a multicomponent NAPL and an enhancedflushing agent solution at the field scale. A relationship is developed to describe enhanceddissolution of a multiple-component NAPL and is used to analyze the field data. While NAPL dissolution behavior was generally complex during the cyclodextrin flush, the initial peak and final effluent concentrations for most of the target contaminantswere within a factor of 2 of the equilibrium values predicted using the ideal enhanced-dissolution theory. This suggests that the dissolution of the multicomponent NAPL during the cyclodextrin flush may be approximately treated, at least for practicalpurposes, as an ideal, equilibrium process. It appears that the dissolution theory successfully predicted the observed behavior for this system. Thus, it may be useful for assisting in the planning, design, and evaluation of other enhanced-flushingapplications involving multicomponent NAPL.