G360 PROJECT TEAM: Dr. Beth Parker, Dr. Peeter Pehme, Steven Chapman, Ryan Kroeker, Maria Gorecka, Jessica Bulova & Brent Redmond (MASc Candidate)
The objective of this project, sponsored by ESTCP (Project ER-201630), is to complete a comprehensive, robust, scientific evaluation of the use of the FLUTe™ Activated Carbon Technology (FACT™) as a low-cost contaminant screening tool for fractured bedrock environments. The evaluation includes developing context and guidelines for interpreting FACT results in a dual porosity system in which groundwater flow and contaminant transport occur in the secondary porosity, and contaminant storage (in solute and sorbed phases) occurs in the primary porosity. Several other complementary methods in the suite of G360 tools in the Discrete Fracture Network – Matrix (DFN-M) Approach will also be employed for evaluation of and comparison with the FACT results. These include: high resolution rock core sampling for contaminant mass distribution in the matrix; Passive Flux Meters (PFMs) deployed behind liners for groundwater and contaminant flux measurement; deployment of button porewater sampling devices (PSDs) and transducers behind liners for groundwater concentrations and hydraulic head characterization, respectively; Active-Distributed Temperature Sensing (A-DTS) and transmissivity profiling for groundwater flow characterization under ambient and stressed conditions, respectively; and installation of different types of multilevel monitoring systems (MLS) for hydraulic head monitoring and groundwater sampling for target contaminants and hydrochemistry.
The detailed performance assessment is being conducted at the former Naval Air Warfare Center (NAWC) site in New Jersey, where the bedrock aquifer is comprised of bedded siltstone/mudstone. Another objective is to assess how varying primary matrix parameters (i.e. porosity and sorption) affects the results through complementary studies at sites in different geologic environments (e.g. granite site in Sweden, sandstone site in California). Other evaluations will include deployment of FACT and other techniques in existing versus newly drilled boreholes to evaluate cross-connection and drilling disturbance effects, and use of different drilling methods (e.g. rapidly drilled air rotary borehole versus slower cored hole). If FACT results are shown to provide a useful measure of the in-situ contaminant distribution / mass flux then this screening tool can be used to improve the quality of site characterizations and conceptual site models (CSMs) while reducing the cost of characterization, which in turn translates into more efficient and effective remedies.