Ronald W. Falta
Dr. Falta’s primary teaching and research interests are in hydrogeology, contaminant transport/remediation, and multiphase heat and fluid flow in porous media. Research projects have largely focused on environmental remediation of hazardous waste sites, geologic sequestration of carbon dioxide, and mathematical modeling of contaminant transport and remediation.
Thermal Remediation Behavior in High and Low Permeability Systems
Thermal remediation is a well-established method for removing volatile and semi-volatile organics from the subsurface. Heat is added by injecting steam in wells, by passing an electrical current through the ground, or by direct conductive heating using heaters. The movement of heat and fluids, and subsequent contaminant removal depends on the heating method, subsurface characteristics, and system design.
In high permeability systems, heat is often delivered as steam due to the high heat injection rates that are possible. Applications that occur below the water table require special consideration of possible gravity override which may occur when injected steam moves upward rather than outward from the injection well. Numerical modeling and a field example show how this phenomenon occurs, and how it can be managed through engineering design.
In low permeability systems, heat is usually delivered by electrical current flow, or by direct conductive heating. Laboratory experiments and numerical modeling results show that little contaminant removal occurs until active boiling occurs in the porous media. Once a connected steam vapor pathway is established, volatile contaminants are removed quickly and only a fraction of the pore water must be boiled away.