Use of Biotracer Tests to Evaluate the Impact of Enhanced-Solubilization Flushing on In-Situ Biodegradation.

Abstract

Biotracers were used in a pilot-scale field study to evaluate the effect of a complexing sugar flush (CSF) on petroleum hydrocarbon biodegradation. Technicalgrade hydroxypropyl-p-cyclodextrin was used during the CSF study, which was conducted in a hydraulically isolated cell. Biodegradation potential was assessed with the use of biotracers. Saturated zone tracer studies employing benzoate, ethanol, and hexanol as chemical analogues for selected petroleum hydrocarbons were conducted prior to and immediately following the CSF study. Biotracer results indicate that cyclodextrin flushing had a negligible effect on the biodegradation of benzoate (representative of toluene), but enhanced the biodegradation of ethanol and hexanol (representative of lower molecular weight alkanes). A microbial evaluation conducted after the experiment indicates that active microbial populations were present following the CSF. This study indicates that biotracers can be used to evaluate the impact of enhanced-solubilization flushing on in-situ biodegradation.