INNOVATIVE APPROACHES FOR GROUNDWATER REMEDIATION USING NATURAL ATTENUATION AND PHYTOREMEDIATION

摘要

This paper presents innovative approaches that use phytoremediation and natural attenuation together to treat a mixture of contaminants in surficial aquifer systems. Two case studies are presented that explore the potential of these technologies when used together. The first case study evaluates the remediation potential of indigenous microorganisms, wetlands, and trees. Investigations showed that the indigenous tree species, which lined the edges of the site, were in part responsible for preventing the offsite spread of groundwater contaminants. The second case study shows approaches for a chlorinated solvent contaminated karst system that used soil vapor extraction to reduce the contamination source; stormwater runoff improvements to limit infiltration in the source area; and the installation of eastern cottonwood trees to contain and treat the contaminated groundwater from migrating offsite and into the limestone formation. Natural attenuation alone was determined to be ineffective in containing the plume because the hydraulics of the karst groundwater were unpredictable and biotransformation of the solvents incomplete. As demonstrated by these case studies, when properly evaluated and combined with contaminant source removal, phytoremediation and natural attenuation can be viable treatment methods for toluene, ethylbenzene, and xylenes (TEX) and chlorinated contaminants in shallow surficial aquifers.