SUITABILITY OF BIOREMEDIATION AT A FORMER SOLVENT RECYCLING SITE

摘要

The shallow aquifer at a former solvent recycling site is contaminated with mineral spirits, a variety of volatile aromatic and chlorinated solvents, and semivolatile organic compounds. Field monitoring was conducted to evaluate existing natural attenuation processes. Monitoring results and evaluation of historical data determined that the site is methanogenic, reductive dechlorination is actively occurring, and the plume is at steady state. However, an unacceptable time frame would be required to meet cleanup levels required for clean closure of this former RCRA treatment, storage, and disposal facility. Monitoring results further indicate that anaerobic biodegradation processes are unlikely to be enhanced by amendments such as electron donors. Laboratory treatability studies were conducted on other in situ alternatives, including surfactant flushing, chemical oxidation, and thermal treatment. Surfactant flushing appeared successful in contaminant removal, however treatment of the extracted surfactant-laden water would be very costly. Site contaminants, especially in soil, were not effectively degraded by chemical oxidation. Thermal treatment at high enough temperatures was successful in reducing contaminant concentrations to required cleanup levels. Although thermal treatment is very costly it appears to be the most promising of the technologies reviewed that would result in a clean closure for the site within a reasonable time frame.