Presentation Date: October 12, 2023
Stringent clean-up standards for benzene and other gasoline range organics can prevent many sites from achieving either no further action or site closure. Often one type of remediation strategy is selected, designed and implemented, with the goal of a longer term “treatment train” strategy towards the end of the project. An example of this is deploying a chemical oxidant such as persulfate. This reagent has many remedial benefits; however, one drawback is the persistence of rebound; sorbed contaminants back diffuse from subsurface sediments and re-contaminate the groundwater. It is common at low concentration sites to allow MNA (monitored natural attenuation) to carry forward for many years eventually reaching the regulatory clean-up standards. Combining two well established technologies ISCO and bioremediation in one implementation can help reduce the timeframe for achieving regulatory compliance. In the summer of 2020 we conducted an injection of a combined remedy that included sodium persulfate and calcium peroxide (ISOC and Bio) to effectively reduce benzene to less than 1 ug/L in 6 months. This presentation will cover the remedial techniques, methods and results, so that other practitioners can attempt a similar strategy at their sites.
Brad Elkins specializes in the application of in situ remediation strategies to treat hazardous compounds in soil and groundwater. He earned a Master’s degree in Geology from East Carolina University and is a registered professional geologist in NC.