The remedial amendments and bioaugmentation cultures commercially available today are the result of considerable research and development. However,
there’s not a universal approach to enhanced biodegradation as each site presents its own unique challenges. For example, even after a successful
amendment injection, elevated contaminant concentrations could inhibit contaminant-degrading microorganisms or low contaminant concentrations may
not be able to sustain an active population of degraders. Bioaugmentation cultures enriched in the laboratory may have survivability issues in the field, and there are still many contaminants that are not addressed by commercial cultures. Three case studies will be presented where in situ bioreactors (ISBRs) built on existing Bio-Sep® bead technology have been shown to address these issues.

The ISBRs are designed to fit within a 2-inch monitoring well and can be adapted for aerobic and anaerobic treatment applications. The ISBRs are filled
with Bio-Sep® beads, which provides a matrix of powdered activated carbon (PAC) and Nomex® that can be rapidly colonized by the active portion of a
microbial community. The PAC adsorbs contaminants and nutrients present in the aquifer and serves to concentrate indigenous degraders for treatment
purposes. Groundwater flow through the bioreactor induce by air lift allows for microorganisms from within the bioreactor to migrate into the formation
beyond the wellbore area to further promote biodegradation in the aquifer. Amendments can be delivered into the unit via topside equipment.
ISBRs have been used to treat both petroleum hydrocarbons and chlorinated solvents as well as other contaminants of concern. This presentation will
provide data from ISBR applications at an industrial site with toluene concentrations exceeding 200 mg/L, a heating oil release with low, yet persistentBTEX concentrations (<100 μg/L), and a chlorinated solvent site where an ISBR was seeded with indigenous microorganisms from a well with a robust population of Dehalococcoides and deployed in another area of the site where reductive dechlorination was limited. Primary Author / Conference Presenter:
Kerry Sublettte
University of Tulsa
Tulsa, Oklahoma, USA

Co-Authors:
Dora Taggart, Microbial Insights, Inc.
Kate Clark, Microbial Insights, Inc.
Sam Rosolina, Microbial Insights, Inc.
Eric Raes, Microbial Insights, Inc.