Formatted Title
Characterization of Target Treatment Zones Using Direct Mass Flux Measurements: A Five-Site Study
Background/Objectives
Background/Objectives. Utilizing flux measurement devices provides essential data that significantly enhances the effectiveness of permeable reactive barrier (PRB) designs. These devices offer a direct measurement of contaminant mass in milligrams that interact with the PRB surface, measured in square meters over a known time period measured in days.
Apart from offering valuable data for PRB design, standard direct flux measurements provide an intricate vertical profile that records the groundwater velocity and contaminant migration rates within the screened interval of a target treatment zone (TTZ). With careful analysis and interpretation, these findings can enhance a practitioner's comprehensive knowledge of the TTZ sections that influence the plume's dimension and configuration. This enables a more targeted application of remedial reagents and optimization of the overall remedial design.
Two of the most critical variables for the successful implementation and performance of PRBs are an accurate groundwater velocity and corresponding contaminant mass flux; however, accurately quantifying these crucial variables poses a challenge when relying on conventional site investigation methods. An accurate understanding of the groundwater velocity and contaminant flux profile can be obtained using in-well flux devices to obtain direct measurements. Direct measured flux results are shown to provide critical input parameters for the development of remedial designs and improve remedial outcomes. These attributes make flux device results useful in design as well as remedial characterization of the TTZ. The results provided by these tools are directly translatable to remedial reagent application programs.
Standard direct measurement flux study results provide a detailed vertical profile of the TTZ’s groundwater velocity and contaminant migration rates across a well’s screened interval. When properly analyzed and interpreted, these results can improve a practitioner’s overall understanding of those sections of the saturated zone that are very likely controlling the size and shape of the plume. Allowing a more focused delivery of remedial reagents as well as optimizing the overall remedial design.
Approach/Activities
Approach/Activities. This presentation will provide direct measurement flux data collected from five sites and will demonstrate the correlations between the presented flux data, site geologic logs, field screening methods (PID logs) and MiHPT. The presentation will highlight how understanding of the TTZ was improved by the addition of mass flux measurements and what implications those changes have on a PRB design.
Results/Lessons Learned
Results/Lessons Learned. Evidence supports that direct flux measurements provide a detailed and accurate assessment of the aquifer and the contaminant plume. Substantial differences exist between traditional site investigative tool results and those obtained using direct measure flux devices, these variances will be graphically illustrated. The incorporation of direct measure flux devices provides significant value in terms of providing characterization at a usable remediation scale as well as directly informing designs which leads to improved remedial outcomes.