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In-Situ Chemical Reduction Treatment Services

Drilling, Project | Mar 18th, 2020

EFS was contracted by a client to provide in-situ chemical reduction (ISCR) treatment services for a site in Ohio. The design remedy consisted of the application of EHC® – a reagent consisting of controlled release carbon, zero-valent iron (ZVI), and nutrients for stimulating the chemical reduction process of organic compounds within groundwater – combined with emulsified ZVI (), and the application of microbes containing dehalococcoides (KB-1®).

This project was performed to promote the reduction of concentrations of chlorinated compounds within groundwater as a result of historical releases from a former dry-cleaning operation at the property. As part of this work scope, a permeable reactive barrier was created utilizing the injected ZVI solution to establish the reductive environment followed by the delivery of dehalococcoides using the KB-1 solution downgradient of the suspected source area to assist in the reductive dechlorination of the groundwater contaminants prior to migrating off-site. Initial injection activities were unable to meet the desired radius of influence (ROI) objectives, therefore, EFS worked with the client to develop an alternate ZVI injection scenario using a different compound (Ferox Plus®) in order to meet and exceed the ROI requirements for the project.

The scope of services provided by EFS included:

  • Preparation of Health and Safety Plans and Project Implementation Plans.
  • Establishment of site perimeter fencing and installation of erosion control measures.
  • Installation of 400 borings over a 40,000 square foot target area to deliver 70,000 pounds of EHC® and 140,000 pounds of Ferox Plus® using DPT equipment
  • Installation of over 100 borings to verify ROI of reagent.
  • Installation of 30 directional injection borings to deliver reagents beneath the occupied building.
  • Installation of 39 borings for the application of KB-1® to promote the complete dechlorination of chlorinated ethenes

All site activities were performed in accordance with USEPA and Ohio EPA concurrence and in accordance with all OSHA requirements. Despite a change in the schedule to overcome initial reagent delivery challenges, EFS was able to complete the project below the budgeted cost.

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