Drew has over 16 years’ experience in remediation design and implementation, project and team management, field support services, and environmental consulting. He is currently Senior Geologist at FRx, where he leads the company’s business development efforts and provides technical support on soil and groundwater remediation projects to clients in the US and Canada. Prior to joining FRx, Drew was the East Region Manager at REGENESIS, where he was responsible for managing sales and technical support associated with the company’s remediation products in the southeastern US. Drew spent his first 5 years in the industry with regional engineering firm Rogers & Callcott Environmental. Drew is based in Charlotte.
PLATFORM PRESENTER - It's All About Amendment Delivery: Are We There Yet?
DPT Jet Injection for Rapid ZVI Delivery in Low-Permeability Zones: Key Results Eighteen Months after Full-Scale Injection
While the deployment of innovative technologies is often presented along with encouraging but preliminary treatment results, longer-term remedial performance does not receive as much attention. We have previously disclosed a novel, patent-pending injection technique for rapid emplacement of remediation amendments in unconsolidated low-permeability soil using custom direct-push technology (DPT) tooling and advanced, high pressure, jet injection methodologies. The performance of DPT jet injection was most recently demonstrated during full-scale treatment of a chlorinated solvent source zone at a site in Denmark, where 49 tons of micro-scale zero valent iron (mZVI) blended with sand was injected into a clay till target treatment zone.
This project includes extensive post-injection characterization and up to 60 months of performance monitoring. Post-injection distribution of mZVI was documented with detailed geologic logging and magnetic susceptibility measurements of 79 soil borings comprising 1,000 meters core. The resulting dense dataset supports the conclusion that DPT jet injection can consistently create subhorizontal mZVI zones with a radius of injection of at least 3 meters. The findings of this work indicate that DPT jet injection is capable of achieving rapid, controlled emplacement of amendments in clay till, thus representing a substantial improvement in performance over conventional injection methods.
Performance monitoring has focused on contaminant destruction within and mass flux out of the treatment zone. Groundwater data indicate that trichloroethene mass discharge from the source area decreased post-injection by 71% after 12 months and 86% after 18 months. The in situ destruction of VOCs and ongoing reactivity of the mZVI has been documented with membrane interface probe (MIP) methods and conventional soil sampling during two post-injection monitoring events. Electrical conductivity measured by MIP have proven useful in identifying mZVI zones. Decreases in chlorinated solvents are co-located with many of these reactive zones, and the total estimated chlorinated solvent mass in soil decreased by 75% in 6 months and 84% in 18 months. The project demonstrates that penetrative distribution of reactive ZVI can effectively and quickly treat high-mass chlorinated solvent source areas in challenging, low-permeability formations.