SERDP ER-1376 Enhancement of In Situ Bioremediation of Energetic Compounds by Coupled Abiotic/Biotic Processes:Final Report for 2004 - 2006

Szecsody, James E.; Comfort, Steve D.; Fredrickson, Herbert L.; Boparai, Hardiljeet K.; Devary, Brooks J.; Thompson, Karen T.; Phillips, J. E.; Crocker, Fiona H.; Girvin, D.C.; Resch, Charles T.; Shea, Patrick J.; Fischer, Ashley E.; Durkin, Lisa

doi:10.2172/936767

Cited by 4 publications

(4 citation statements)

References 60 publications

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“…TNT is biodegradable under both aerobic and anaerobic conditions (Won and Borden, 2016). Under anaerobic conditions, transport is limited by covalent binding of transformation products to soil surfaces (Szecsody et al, 2007; Kalderis et al, 2011).…”

mentioning

confidence: 99%

Natural and Enhanced Attenuation of Explosives on a Hand Grenade Range

2017

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2,4,6-Trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (Royal Demolition Explosive, or RDX) deposited on hand grenade training ranges can leach through the soil and impact shallow groundwater. A 27-mo field monitoring project was conducted to evaluate the transport and attenuation of high explosives in variably saturated soils at an active grenade range located at Fort Bragg, NC. Two approaches were evaluated: (i) natural attenuation in grenade Bay C; and (ii) enhanced attenuation in Grenade Bay T. There was no evidence of TNT accumulation or leaching in surface soils or pore water in either bay, consistent with parallel laboratory studies showing aerobic and anaerobic biodegradation of TNT. In the untreated Bay C, the low saturated hydraulic conductivity () combined with high rainfall and warm summer temperatures resulted in reducing conditions (low oxidation-reduction potential), an increase in dissolved Mn, and a rapid decline in nitrate and RDX. In Bay T, the somewhat greater and lower soil organic C level resulted in more oxidizing conditions with greater RDX leaching. A single-spray application of glycerin and lignosulfonate to the soil surface in Bay T was effective in generating reducing conditions and stimulating RDX biodegradation for ∼1 yr.

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confidence: 99%

Natural and Enhanced Attenuation of Explosives on a Hand Grenade Range

2017

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“…Under these conditions, the activity of the indigenous microbial population is significantly reduced and the populations may not be able to recover from the chemical treatment. Similarly, measurements of total microscopic counts (acridine orange staining) and 14 C-acetate mineralization rates have shown an order of magnitude lower cell counts and a 10-time reduction in acetate mineralization rates as a result of a 2*di/Fe ratios (Szecsody et al 2007a). In contrast to NDMA, the dithionite treatment stimulated the mineralization of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) by the microbial populations as a result of a combined abiotic/biotic transformation of the energetics (Szecsody et al 2007a).…”

Section: 34mentioning

confidence: 92%

“…If the carbon mass is not in aqueous solution (i.e., the aqueous measurement accounts for all aqueous species, additional chromatograph separation is needed to measure 14 C-NDMA, as described in Section 4.0), it could be present in the headspace as volatile compounds that are not sequestered in the CO 2 trap (i.e., 1-M NaOH). A carbon trap (i.e., activated carbon) in the headspace can be used to trap any of these volatile organic compounds, as was previously reported for RDX mineralization (Szecsody et al 2007a). …”

Section: Carbon Mass Balance In Reduced Systemsmentioning

confidence: 99%

Abiotic and Biotic Mechanisms Controlling In Situ Remediation of NDMA

Szecsody¹,

McKinley²,

Breshears³

et al. 2009

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Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. REPORT DATE MAY 20092. REPORT iii Executive SummaryThis project was initiated to investigate whether in situ coupled abiotic/biotic degradation of N-nitrosodimethylamine (NDMA, an emerging contaminant) could be used as a permeable reactive barrier for remediation at the Aerojet, California site, where groundwater contains up to 36-ppb NDMA. The sediment mainly used in experiments is from the Aerojet groundwater aquifer (260-ft depth), with additional sediments from other groundwater aquifers (i.e., not shallow soils, Ft. Lewis, Washington, 60-ft depth, Puchack, New Jersey, 273-ft depth). Different in situ remediation processes were compared in this study: a) biostimulation (oxic, anaerobic, iron-reducing, sulfate-reducing), b) abiotic iron-reducing environment (by dithionite reduction of sediment or zero valent iron addition), c) coupled abiotic/biotic remediation (iron-reducing environment), and d) sequential iron-reducing, then oxic, biostimulation. The overall goal was to understand and optimize the combined effects of abiotic and biotic processes to degrade NDMA to nontoxic products. Iron-reducing conditions were created by chemical reduction of a sediment using sodium dithionite, and in a few cases, a natural reduced aquifer sediment or sediment with zero valent iron addition.When subsurface sediments are chemically or naturally reduced, abiotic surface phase(s) rapidly degraded NDMA (8-hour half-life for high reduction, slower for low reduction) to nontoxic dimethylamine (DMA). Experiments showed up to 80% conversion of NDMA to DMA, with further degradation to nitrate (up to 40% molar conversion), formate (trace concentration) and carbon dioxide (up to 82% molar conversion). Methylamine and formaldehyde (likely intermediates) were not detected. Experiments with 100 and 10 ng/L NDMA starting concentration had a rapid degradation half-life (4.7 hours), and NDMA was degraded to <3 ng/L (detection limit). Although degradation to DMA is sufficient for remediation (DMA is not toxic at <5 mg/L), because NDMA mass was degraded further to more toxic intermediates, NDMA mineralization (i.e., to CO 2 ) was considered the lowest risk product, and was the main focus of this study. NDMA degradation was most rap...

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“…Similarly, measurements of total microscopic counts (acridine orange staining) and 14 C-acetate mineralization rates have shown an order of magnitude lower cell counts and a 10-time reduction in acetate mineralization rates as a result of a 2*di/Fe ratios (Szecsody et al 2007a). In contrast to NDMA, the dithionite treatment stimulated the mineralization of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) by the microbial populations as a result of a combined abiotic/biotic transformation of the energetics (Szecsody et al 2007a). …”

Section: 34mentioning

confidence: 92%

SERDP ER-1421 Abiotic and Biotic Mechanisms Controlling In Situ Remediation of NDMA: Final Report

Szecsody¹,

McKinley²,

Crocker³

et al. 2009

Self Cite

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Executive SummaryThis project was initiated to investigate whether in situ coupled abiotic/biotic degradation of N-nitrosodimethylamine (NDMA, an emerging contaminant) could be used as a permeable reactive barrier for remediation at the Aerojet, California site, where groundwater contains up to 36-ppb NDMA. The sediment mainly used in experiments is from the Aerojet groundwater aquifer (260-ft depth), with additional sediments from other groundwater aquifers (i.e., not shallow soils, Ft. Lewis, Washington, 60-ft depth, Puchack, New Jersey, 273-ft depth). Different in situ remediation processes were compared in this study: a) biostimulation (oxic, anaerobic, iron-reducing, sulfate-reducing), b) abiotic iron-reducing environment (by dithionite reduction of sediment or zero valent iron addition), c) coupled abiotic/biotic remediation (iron-reducing environment), and d) sequential iron-reducing, then oxic, biostimulation. The overall goal was to understand and optimize the combined effects of abiotic and biotic processes to degrade NDMA to nontoxic products. Iron-reducing conditions were created by chemical reduction of a sediment using sodium dithionite, and in a few cases, a natural reduced aquifer sediment or sediment with zero valent iron addition.When subsurface sediments are chemically or naturally reduced, abiotic surface phase(s) rapidly degraded NDMA (8-hour half-life for high reduction, slower for low reduction) to nontoxic dimethylamine (DMA). Experiments showed up to 80% conversion of NDMA to DMA, with further degradation to nitrate (up to 40% molar conversion), formate (trace concentration) and carbon dioxide (up to 82% molar conversion). Methylamine and formaldehyde (likely intermediates) were not detected. Experiments with 100 and 10 ng/L NDMA starting concentration had a rapid degradation half-life (4.7 hours), and NDMA was degraded to <3 ng/L (detection limit). Although degradation to DMA is sufficient for remediation (DMA is not toxic at <5 mg/L), because NDMA mass was degraded further to more toxic intermediates, NDMA mineralization (i.e., to CO 2 ) was considered the lowest risk product, and was the main focus of this study. NDMA degradation was most rapid with high sediment reduction. These sediments had a higher mass of ferrous surface phases (ferrous oxides, carbonates, sulfides, adsorbed ferrous iron, green rust) and a more alkaline pH (pH increased from 9.1 to 10.5). The NDMA reactivity of these different iron phases showed that adsorbed ferrous iron was the dominant reactive phase that promoted NDMA reduction. Alkaline hydrolysis by itself (no sediment, pH 11) did not degrade NDMA, nor did alkaline hydrolysis with anaerobic sediment (a potential catalyst). Iron sulfides, while present in the reduced sediment, did not change the NDMA degradation rate. Iron(II) carbonate (siderite) also showed little reactivity with NDMA, as its removal did not influence NDMA degradation. Although magnetite itself (with no sediment) did not promote NDMA degradation, magnetite removal from the reduced sediment...

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SERDP ER-1376 Enhancement of In Situ Bioremediation of Energetic Compounds by Coupled Abiotic/Biotic Processes:Final Report for 2004 - 2006

Cited by 4 publications

References 60 publications

Natural and Enhanced Attenuation of Explosives on a Hand Grenade Range

Natural and Enhanced Attenuation of Explosives on a Hand Grenade Range

Abiotic and Biotic Mechanisms Controlling In Situ Remediation of NDMA

SERDP ER-1421 Abiotic and Biotic Mechanisms Controlling In Situ Remediation of NDMA: Final Report

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