Extensive laboratory and field studies have shown that EOS® will support anaerobic biodegradation for three to five years depending on the amount of substrate injected and site conditions. In a laboratory column study, Long and Borden (2005) showed that a single injection of emulsified soybean oil can support complete reductive de-chlorination of 10,000 µg/L to PCE to ethene for up to seven years. Field tests of the emulsified oil technology by the Air Force Center for Environmental Excellence (AFCEE) have shown that emulsified edible oils have lasted over three and one-half years at Dover Air Force Base (AFB), over three years at Edwards AFB, and over two and one-half years at Altus AFB. A recent biobarrier project supported by the Environmental Security Technology Certification Program demonstrated that a single EOS injection lasted over one and one-half years while reducing influent perchlorate concentrations to below detection (over 99.9% reduction) with concurrent reduction of 1,1,1-TCA to non-toxic end-products (Zawtocki et al., 2004). Monitoring is continuing to evaluate the effective life of this barrier.
Based on bench scale and field studies, proper application of EOS® should last at least three to five years in the aquifer. As part of the engineering design criteria, you control the life expectancy of the remediation. Your EOS Remediation representative can assist you with designing sufficient substrate life for your project.