Formatted Title
The Anatomy of a Defensible Case Study
Background/Objectives
There are many case studies prepared and published in the remediation by consultants, chemistry vendors, and injection/turnkey contractors. This presentation will focus on injection/turnkey contractors to provide clarity on what a defensible case study should include, so that the results can be effectively evaluated to make sound decisions on remediation approaches.
Approach/Activities
When developing a case study, the following detail should be provided.
- How was the site characterized?
- How was contaminant mass distribution determined? Traditional or high resolution
- Were all phases of contamination quantified (soil, groundwater, NAPL, vapor)
- How were target remediation intervals selected and impact on remediation goals?
- Hydraulic conductivity of target interval and supporting well logs?
- Seepage velocity of target interval and how determined?
- Degree of heterogeneity of target interval?
- Any unsaturated soil or smear zone contamination addressed?
- Any source mass not addressed, e.g., underneath a building?
- Basis for chemistry selection?
- Baseline concentrations (max,avg) vs remediation goals?
- Dosing Calculations and were safety or confidence factors used?
- Were all contaminants and scavenging reactions considered?
- Persistence and injectability of chemistry?
- Was a bench scale test performed?
- Overall lbs of chemistry used and cost?
- Previous remediation approaches at the site and results.
- Basis for the injection approach?
- If bioaugmentation used, overall mixing and injection approach.
- Pressure and flow regulatory limitations?
- Injection pump pressure, flow, and solid slurry capacity?
- Mixing technology and approach?
- Radius of Influence Basis
- Chemistry injection concentrations?
- Injection tooling in relation to target intervals?
- For DPT, Top-Down or Bottom-Up?
- Overall Injection days and costs
- During and Post Remediation Performance Monitoring
- Proximity of Injection locations versus monitoring well network?
- Were chemistries detected in monitoring wells and how did that impact the start of performance monitoring?
- How many months of performance monitoring data is provided and how much is required by regulators.
- Was soil data included and what approach used to ensure soil samples were representative of the site.
Results/Lessons Learned
Cascade will also present an in situ remediation case study that includes these items.