Designing, Assessing, and Demonstrating Sustainable Bioaugmentation for Treatment of DNAPL Sources in Fractured Bedrock
Technical Report,01 Apr 2012,01 Jan 2017
CB and I Federal Services, LLC. Lawrenceville United States
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Bioaugmentation was applied to treat the DNAPL sources present in the fracture zones that were targeted for investigation using the partitioning tracer testing. Nine months of active treatment using groundwater re-circulation with electron donor and nutrient delivery was followed by a 10-month rebound period. While enhanced dissolution of the DNAPL sources was observed in both the shallow and deep fractures intervals, a greater extent of DNAPL mass removal approximately 100 was observed in the shallow fracture zone, while only 45 of the DNAPL was removed in the deep zone. The difference in DNAPL mass removal between the two zones was attributed to the DNAPL architecture, as the flow field in the deep zone was more complex, and a greater extent of the DNAPL was present in mass transfer controlled zones. Furthermore, while no increases in chlorinated ethenes or ethene was observed in the shallow zone during the 10-month rebound period, data suggest the sum of chlorinated ethenes and ethene concentrations were increasing during rebound in the deep zone, likely due to the persistence of residual DNAPL sources. This highlights the relationship between DNAPL architecture and remedial performance.
- Environmental Health and Safety