Journal article
Sustained and Complete Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (RDX) Degradation in Zero-Valent Iron Simulated Barriers under Different Microbial Conditions
Environmental Technology, Vol.26(10), pp.1115-1126
10/01/2005
DOI: 10.1080/09593332608618474
PMID: 16342534
Abstract
Flow-through columns packed with "aged" zero-valent iron (ZVI) between layers of soil and sand were constructed to mimic a one-dimensional permeable reactive iron barrier (PRB). The columns were continuously fed RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine, ca. 18 mg l
−1
) for over one year. Two columns were bioaugmented with dissimilatory iron reducing bacteria (DIRB) Shewanella algae BrY or Geobacter metallireducens GS-15 to investigate their potential to enhance the reactivity of aged iron by reductive dissolution of passivating iron oxides or via production of biogenic reactive minerals. A third column was not bioaugmented to evaluate colonization by indigenous soil microorganisms. [
14
C]-RDX was completely removed in all columns at the start of the iron layer, and concentration profiles showed rapid and sustainable RDX removal over one year; however, a phylogenetic profile conducted after one year using DGGE analysis of recovered DNA did not detect S. algae BrY or G. metallireducens in their respective columns. Bacterial DNA was recovered from within the ZVI. Several unidentified
14
C-labeled byproducts were present in the effluent of all columns. Dissolved
14
C removal and the detection of dissolved inorganic
14
C in these columns (but not in the sterile control) suggest microbial-mediated mineralization of RDX and sorption/precipitation of degradation products. Enhanced RDX mineralization in bioaugmented columns was temporary relative to the indigenously colonized column. However, shorter acclimation periods associated with bioaugmented PRBs may be desirable for rapid RDX mineralization, thereby preventing breakthrough of potentially undesirable byproducts. Overall, these results show that high RDX removal efficiency by ZVI-PRBs is achievable and sustainable and that the efficacy and start-up of ZVI-PRBs might be enhanced by bioaugmentation.
Details
- Title: Subtitle
- Sustained and Complete Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (RDX) Degradation in Zero-Valent Iron Simulated Barriers under Different Microbial Conditions
- Creators
- J. D ShroutP Larese-CasanovaM. M SchererP. J Alvarez
- Resource Type
- Journal article
- Publication Details
- Environmental Technology, Vol.26(10), pp.1115-1126
- Publisher
- Taylor & Francis Group
- DOI
- 10.1080/09593332608618474
- PMID
- 16342534
- ISSN
- 0959-3330
- eISSN
- 1479-487X
- Language
- English
- Date published
- 10/01/2005
- Academic Unit
- Civil and Environmental Engineering
- Record Identifier
- 9983992059102771
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