Publications Details
Development of dry barriers for containment and remediation at waste sites
This paper describes a concept in which dry air is injected into an unsaturated formation to reduce the soil moisture content, referred to here as a dry (or sometimes tensiometric) barrier. The objective is to reduce the hydraulic conductivity of the unsaturated media to the point where liquid phase transport becomes negligible, thereby achieving containment. The concept could be applied in subsurface formations to provide containment from a leaking facility, or it could be incorporated into a cover design to provide redundancy for a capillary barrier. The air injection process could in principle be coupled with a vacuum extraction system to recover soil vapors, which would then provide a remediation process that would be appropriate if volatile organic compounds were present. Work to date has consisted of a combined theoretical, laboratory, and field research investigation. The objective of this research was to demonstrate the technical feasibility of the dry barrier concept by identifying the parameters which determine its effectiveness. Based on the results obtained for the experimental and theoretical studies, feasibility analyses were prepared for as a modification for a landfill cover design to prevent infiltration from atmospheric precipitation and for potential application of dry barriers to achieve subsurface containment and removal of volatile constituents. These analyses considered the technical as well as the economic aspects of the dry barrier concept.