Abstract:
Remediation of contaminated groundwater at hazardous waste sites is undergoing a tremendous shift from the conventional "pump and treat" containment remedies to more effective and aggressive source area technologies in combination with Monitored Natural Attenuation (MNA). This paper presents information on the latest trends in groundwater remediation for Chlorinated Volatile Organic Chemicals (cVOCs) and compares some of the "hottest" technologies. An example conceptual site model is presented, with focus on cVOCs in a sandy shallow aquifer. Contaminant "states" shown include mobile/pooled Nonaqueous Phase Liquid (NAPL) (free product), residual NAPL, sorbed contaminants, and dissolved contaminants. General strategies for groundwater remediation are applied to source zones, plumes, and a combination of the two. Source zone strategies include containment, aggressive source zone treatment, and partial mass removal from source zones. Strategies for the plume include containment, complete plume treatment, plume "hot spot" treatment with MNA for rest of the plume, and MNA for the entire plume. Applied source zone and plume technologies are discussed; some of them are common and others are relatively new technologies. After a qualitative comparison of these technologies, example applications are presented on two in situ strategies: electrical resistive heating coupled with enhanced reductive dechlorination (bioremediation) and Zero Valent Iron/clay-soil mixing.
