Fe(0)-Based-Bioremediation of RDX-Contaminated Groundwater
IOWA UNIV IOWA CITY DEPT OF CIVIL AND ENVIRONMENTAL ENGINEERING
Pagination or Media Count:
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 Fe0 permeable reactive barrier, with focus on investigating RDX mechanisms and the sustainability and robustness of an integrated microbial-Fe0 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 Fe0 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.
- Hydrology, Limnology and Potamology
- Ammunition and Explosives
- Water Pollution and Control