Fe(0)-Based-Bioremediation of RDX-Contaminated Groundwater

RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) is an explosive compound that is gaining notoriety as a recalcitrant and toxic groundwater contaminant at many military installations. Batch and flow-through column studies suggest that permeable reactive iron barriers (PRBs) should effectively intercept...

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Bibliographic Details
Main Authors: Shrout, Joshua D, Sutton, Brett, Sherburne, Leslie, Larese-Casanova, Phil, Scherer, Michelle M, Parkin, Gene F, Valentine, Richard L, Just, Craig L, Alvarez, Pedro J
Format: Report
Language:English
Subjects:
ACETOBACTERIUM PALUDOSUM
Ammunition and Explosives
BACTERIA
Biochemistry
BIODEGRADATION
FE-BASED-BIOREMEDIATION
GROUND WATER
Hydrology, Limnology and Potamology
IRON
PRB(PERMEABLE REACTIVE IRON BARRIERS)
RDX
RDX-CONTAMINATED GROUNDWATER
Water Pollution and Control
WATER TREATMENT
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Summary:RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) is an explosive compound that is gaining notoriety as a recalcitrant and toxic groundwater contaminant at many military installations. Batch and flow-through column studies suggest that permeable reactive iron barriers (PRBs) should effectively intercept and degrade RDX plumes, and that treatment efficiency could be enhanced by some biogeochemical interactions. This project addresses the potential to enhance RDX degradation by bioaugmentation of an Fe(0) permeable reactive barrier, with focus on investigating RDX mechanisms and the sustainability and robustness of an integrated microbial-Fe(0) treatment system. Activities completed this year included chemical characterization including assessing the subsequent degradability of unknown soluble metabolites formed during RDX transformation. Such byproducts were mineralized faster and to a greater extent to carbon dioxide than the parent RDX compound. A significant fraction of carbon from RDX formed under abiotic conditions was confirmed to be formaldehyde. We also continued to run flow-through column studies to investigate the sustainability of these systems. The RDX degradation profile for columns containing aged iron was determined and these columns were characterized with respect to their microbial communities and iron oxides formed along the length of the simulated Fe(0) barrier. Lastly, our investigation with the homoacetogen Acetobacterium paludosum has indicated that RDX can serve as a nitrogen source for this bacterium. This report details the importance, relevance, and scope of this work and the achievement of milestones for this research in 2003.