Challenges Associated with Large-Scale Enhanced Anaerobic Dechlorination near Sao Paulo, Brazil

摘要

Background/Objectives. The application of enhanced anaerobic dechlorination (EAD) to remediate groundwater impacted with chlorinated volatile organic compounds (CVOCs) at a an active manufacturing facility near Sao Paulo posed challenges with respect to hydrogeology, low aquifer pH, contaminant distribution, and on-site/off-site access. A subsurface investigation of this industrial facility conducted in 2007 revealed two separate plumes of groundwater impacted with tetrachloroethene (PCE) and its degradation products, which cover an approximate 12-acre area and extend to depths of approximately 60 feet below ground surface. Based on technical feasibility, cost, and implementability criteria, active groundwater remediation using EAD technology has been implemented at this site. The implementation strategy consisted of a two-phased approach. Phase 1 was implemented in late 2012 and was designed to expeditiously restrict migration of impacted groundwater onto hydraulically downgradient properties. Phase 2 was implemented in 2013 and was designed to meet groundwater remedial objectives modeled in a 2011 Human Health Risk Assessment.