Environmental Field Services was contracted by an Illinois-based engineering company to provide in-situ chemical reduction (ISCR) treatment services for a site located in Michigan. The site formerly housed commercial dry cleaning operations from the 1950s through 1980. Evidence of solvent impacts were detected in soils, groundwater, and within indoor air of adjacent properties including schools, churches, and residences. Prior remediation efforts consisting of demolition, source removal, installation of a soil vapor extraction system, and installation of a groundwater pump and treatment system were performed between 2007 and 2013. The ISCR scope of work was proposed in order to enhance the effectiveness of the pump and treat system and to reduce the overall time to meet the site objectives for groundwater.
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®) to promote the complete dechlorination of chlorinated ethenes.
EFS completed the application utilizing direct push injection equipment to successfully deliver the reagents to the targeted intervals between 15 and 65 feet below grade over an approximately 15,000 square foot area. EFS installed 72 injection points to deliver 122,000 pounds of EHC® and 1,500 gallons of eZVI to the desired intervals within the plume. EFS also injected 160 liters of KB-1® at 133 boring locations within and outside of the treatment zone to further promote bioaugmentation within the groundwater. The project was completed within budget and the injection activities were completed in 12 weeks.