A New Framework for Accelerated Site Closure: Dynamic Remedy Implementation
The presented case study illustrates the application and performance of Directed Groundwater Recirculation (DGR). The most important difference between DGR and conventional P&T is the reliance on the CSM to develop a hydraulic flushing framework, a dynamic operation plan, and the approach for continuous adaption based on actual remedial performance. The DGR system is operating at 65gpm to remediate the diffuse plume and overcome the challenges of advection and stagnation. The system began operation in December 2014 with 29-extraction-wells and 58-extraction-wells with contractually driven goals, to allow property transfer within 18 months, and regulatory goals thereafter. The DGR system removed most of mass within 8 months, meeting contractual obligations for property transfer everywhere. Regulatory criteria in the shallow portion of the aquifer have been met. Details will be presented to discuss lingering, low-concentration exceedances in deep portions of the aquifer, required further efforts to achieve stringent criteria for vinyl chloride (2µg/L).