Solute Effects in Aquifer Cleanup/Hazardous Waste Treatment by Oxy-Radical Processes

Ground water which has been contaminated by improper disposal of organic chemicals is usually cleaned up either by air stripping or granular activated carbon adsorption, both of which still leave a pollution problem when "treatment" is completed. Several Illinois Superfund sites are candidates for cleanup of ground water, and Illinois EPA is now facing the problem of how best to clean these sites, using as much on-site technology as possible. Oxy-radical processes have been shown to be powerful methods for the destruction of organic compounds in water. Photolytic ozonation, in particular, has been proven effective for the complete conversion of organic compounds to carbon dioxide and water, organochlorine to chloride, etc. However, some solutes present in ground water (e.g. sulfate, phosphate, and bicarbonate) are known hydroxyl radical scavengers and may interfere with treatment, if present in high concentrations. On the other hand, the scavenging products, which are radical anions, are known to react preferentially with some organic compounds. The purpose of the research was to investigate the extent of natural solute interference/enhancement of important treatment reactions, to determine concentration ranges in which the effects become dominant upon the kinetics of oxy-radical treatment processes, and to identify any classes of compounds for which treatment reactions may actually be enhanced by the presence of such solutes.