LABORATORY STUDY OF AIR SPARGING - AIR-FLOW VISUALIZATION

Laboratory flow visualization experiments. using glass beads as the porous medium, were conducted to study air sparging, an innocative technology for subsurface contaminant remediation. The purpose of these experiments was to observe how air flows through saturated porous media and to obtain a basic understanding of air plume formation and medium heterogeneity effects. The experiments indicate that air flow occurring in discrete, stable channels is the most probable flow behavior in medium to fine grained water saturated porous media and that medium heterogeneity plays an important role in the development of air channels. Several simulated scales of heterogeneities, from pore to field, have been studied. The results suggest that air channel formation is sensitive to the various scales of heterogeneities. Site-specific hydrogeologic settings have, to be carefully reviewed before air sparging is applied to remediate sites contaminated by volatile organic compounds.