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ITRC Guidance Document: Optimizing Injection Strategies and In Situ Remediation Performance
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An introduction to the Interstate Technology and Regulatory Council (ITRC) Optimizing Injection Strategies and In Situ Remediation Performance Technical Regulatory Guidance Document will be presented.

The comprehensive web-based interactive regulatory guidance document and companion web-based training were developed to guide remediation practitioners through the design and implementation of successful in situ remedies.

In situ remediation technologies have advanced to mainstream acceptance and can offer performance, cost, and schedule advantages over many ex situ soil and groundwater treatment approaches. Developing a detailed, site-specific strategy is critical to the success of such in situ remedies. Central to this strategy is the collection of site characterization information sufficient to develop a conceptual site model (CSM) that is detailed enough to guide in situ design – amendment selection, delivery approach, and performance monitoring program. In the interest of developing expedited solutions, many in situ remediation projects have been executed based on an incomplete understanding of site geology, hydrogeology, geochemistry, microbiology, and contaminant nature and extend. Some sites have undergone multiple rounds of in situ injections but have not progressed toward closure. Better strategies and minimum design standards are required to decrease uncertainty and improve remedy effectiveness.

The remedial design process is commonly represented and approached as a linear sequence of steps that begin with the conceptual site model. In practice, a properly executed in situ remedial design process is iterative and cyclical with feedback loops at each step connecting to earlier and/or later steps. The remedial design process involves combining an understanding of site characteristics (including contaminant properties and distribution), the physical properties of amendments, amendment delivery method and dose. When developing a remedial design, it is important to consider the following:

  • The data set for a site upon which to develop a conceptual site model and corresponding design will never be perfect or fully complete;
  • Factors that influence design cross many orders of magnitude in scale, from the molecular level to the site-wide level;
  • Site conditions change at timeframes that range from minutes to decades;
  • Although site models and designs often assume hydrogeologic homogeneity of the subsurface, heterogeneity is the rule; and

Distribution is dependent on the site geology, hydrogeology, and delivery method but amendment transport in the subsurface often appears chaotic due to small scale heterogeneities.

The Optimizing Injection Strategies and In Situ Remediation Performance guidance identifies challenges that may impede or limit remedy effectiveness and describes strategies for developing specific actions that can be applied to optimize the design and performance of in situ remediation projects. The guidance document and presentation will include case studies and a review of commonly encountered field and design issues and resolutions.

Publication Summary

  • Geosyntec Authors: Suzanne O'Hara
  • All Authors: Suzanne O'Hara
  • Title: RPIC 2021
  • Event or Publication: Event
  • Practice Areas: Contaminated Site Assessment and Cleanup
  • Citation: Geosyntec, Savron (a Geosyntec company), and SiREM (a Geosyntec company practitioners will present virtually at the Workshop from November 15-18, 2021.
  • Date: November 15-18, 2021
  • Location: Online
  • Publication Type: Platform Presentation