Background

The objective of this study is to assess the effects of adding soluble divalent iron (DVI) to emulsified electron donor mixtures to promote the biogeochemical destruction of four common chlorinated ethenes – perchlorethylene, trichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride (VC)-as part of electron donor mixture enhanced reductive dechlorination treatments in groundwater. Twenty-four project sites were studied, comprising 100 performance monitoring wells across the U.S. Wells that received DVI treatment showed increased dechlorination rates, improved contaminate reduction, and limited daughter product formation relative to the wells that did not receive DVI treatment. Following injection of electron donor treatments and DVI, the time required for a well to reach 90% reduction from a peak concentration was improved for the 25, 50, and 75% confidence intervals for the four chlorinated ethenes studied relative to an approach using electron donor mixture treatments alone. The total improvement in time to degrade chlorinated ethenes through VC was also improved. Daughter product formation was also less for wells where DVI was added to the electron donor mixture. The cost to add a DVI amendment was less than $3 per cubic yard as applied.

Addition of Divalent Iron To Electron Donor Mixtures For Remediation Of Chlorinated Ethenes: A Study Of 100 Wells