Analytical model for BTEX natural attenuation in the presence of fuel ethanol and its anaerobic metabolite acetate

Silva, Marcio L. B. Da; Gómez, Diego E.; Alvarez, Pedro J. J.

doi:10.1016/j.jconhyd.2012.12.006

Cited by 8 publications

(2 citation statements)

References 35 publications

(37 reference statements)

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“…Furthermore, contaminated sites commonly contain mixtures of co-contaminants that make it more difficult to predict the overall effect that biodegradation has on water quality and human health. For example, the addition of ethanol to hydrocarbon plumes containing BTEX, either by addition to transport fuels or via accidental release, can impact BTEX biodegradation rates and mechanisms. − The addition of labile organic matter can also cause the reduction of Fe(III) and the release of trace elements associated with Fe(III) to groundwater. , …”

Section: Introductionmentioning

confidence: 99%

Rates of As and Trace-Element Mobilization Caused by Fe Reduction in Mixed BTEX–Ethanol Experimental Plumes

Ziegler

McGuire

Cozzarelli

2015

Environ. Sci. Technol.

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Biodegradation of organic matter, including petroleum-based fuels and biofuels, can create undesired secondary water-quality effects. Trace elements, especially arsenic (As), have strong adsorption affinities for Fe(III) (oxyhydr)-oxides and can be released to groundwater during Fe-reducing biodegradation. We investigated the mobilization of naturally occurring As, cobalt (Co), chromium (Cr), and nickel (Ni) from wetland sediments caused by the introduction of benzene, toluene, ethylbenzene, and xylenes (BTEX) and ethanol mixtures under iron- and nitrate-reducing conditions, using in situ push-pull tests. When BTEX alone was added, results showed simultaneous onset and similar rates of Fe reduction and As mobilization. In the presence of ethanol, the maximum rates of As release and Fe reduction were higher, the time to onset of reaction was decreased, and the rates occurred in multiple stages that reflected additional processes. The concentration of As increased from <1 μg/L to a maximum of 99 μg/L, exceeding the 10 μg/L limit for drinking water. Mobilization of Co, Cr, and Ni was observed in association with ethanol biodegradation but not with BTEX. These results demonstrate the potential for trace-element contamination of drinking water during biodegradation and highlight the importance of monitoring trace elements at natural and enhanced attenuation sites.

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Section: Introductionmentioning

confidence: 99%

Rates of As and Trace-Element Mobilization Caused by Fe Reduction in Mixed BTEX–Ethanol Experimental Plumes

Ziegler

McGuire

Cozzarelli

2015

Environ. Sci. Technol.

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“…Aerobic biodegradation relies on dissolved oxygen (DO) as the electron acceptor used by the subsurface microorganisms. Anaerobic processes refer to a variety of biodegradation mechanisms that use nitrate, ferric iron [Fe(III)], sulfate, and carbon dioxide (CO 2 ) as terminal electron acceptors [4,5]. Natural remediation processes include physical, chemical, and biological transformation (e.g., aerobic/anaerobic biodegradation, cometabolism, dispersion, volatilization, oxidation, reduction, and adsorption) [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Effects of Aquifer Heterogeneity and Geochemical Variation on Petroleum-Hydrocarbon Biodegradation at a Gasoline Spill Site

Lien

Lee

et al. 2014

AMR

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In subsurface environment, small-scale heterogeneities usually cause the reduction of the applicability of in situ remedial techniques. Biogeochemical heterogeneities and preferential groundwater flow paths create complex hydrogeologic conditions at most contaminated sites. A thorough understanding of the resulting three-dimensional distribution of contaminants is a necessity prior to determining a need for remediation. In this study, a gasoline spill site was selected to examine the effects of aquifer heterogeneities and geochemical variations on petroleum hydrocarbon biodegradation via different oxidation-reduction process. At this site, two multilevel sampling wells were installed to delineate the lateral (5 m) and vertical (0.5 m) distribution of contaminant concentrations and different biogeochemical parameters. Two 5-cm (I.D.) continuous soil cores [from 4 to 8 m below land surface (bls)] were collected within the gasoline plume to evaluate the distribution of the microbial population in soils. Results show that high microbial activities were observed in soil samples based on the following evidences: (1) high petroleum hydrocarbon degradation rate, and (2) high microbial biomass. Each soil section was used for chemical extraction, microbial enumeration, and grain size distribution. Results show that the soil sections with more permeable sediment materials corresponded with higher biomass (total anaerobes > 2 x 106cells/g) and significant contaminant degradation. However, those sections with less permeable sediments contained lower microbial population. Results indicate that the subsurface microorganisms were distributed unevenly in the aquifer, and some regions were devoid of microorganisms and biodegradation activities. Spatial distribution of microorganisms, soil materials, and biogeochemical characteristics in the subsurface soils control the extent and kinetics of contaminant biodegradation. Thus, using blended aquifer materials for measurement of in situ biodegradation rates may not achieve representative results.

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Bioremediation via in situ Microbial Degradation of Organic Pollutants

Vogt

Richnow

2013

Advances in Biochemical Engineering/Biotechnology

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Contamination of soil and natural waters by organic pollutants is a global problem. The major organic pollutants of point sources are mineral oil, fuel components, and chlorinated hydrocarbons. Research from the last two decades discovered that most of these compounds are biodegradable under anoxic conditions. This has led to the rise of bioremediation strategies based on the in situ biodegradation of pollutants. Monitored natural attenuation is a concept by which a contaminated site is remediated by natural biodegradation; to evaluate such processes, a combination of chemical and microbiological methods are usually used. Compound specific stable isotope analysis emerged as a key method for detecting and quantifying in situ biodegradation. Natural attenuation processes can be initiated or accelerated by manipulating the environmental conditions to become favorable for indigenous pollutant degrading microbial communities or by adding externally breeded specific pollutant degrading microorganisms; these techniques are referred to as enhanced natural attenuation. Xenobiotic micropollutants, such as pesticides or pharmaceuticals, contaminate diffusively large areas in low concentrations; the biodegradation pattern of such contaminations are not yet understood.

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Analytical model for BTEX natural attenuation in the presence of fuel ethanol and its anaerobic metabolite acetate

Cited by 8 publications

References 35 publications

Rates of As and Trace-Element Mobilization Caused by Fe Reduction in Mixed BTEX–Ethanol Experimental Plumes

Rates of As and Trace-Element Mobilization Caused by Fe Reduction in Mixed BTEX–Ethanol Experimental Plumes

Effects of Aquifer Heterogeneity and Geochemical Variation on Petroleum-Hydrocarbon Biodegradation at a Gasoline Spill Site

Bioremediation via in situ Microbial Degradation of Organic Pollutants

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