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In-Situ Chemical Reduction

Project, Remedial Construction | Nov 25th, 2019

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 (eZVI), 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 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:

  • 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 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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