Effect of ethanol on BTEX biodegradation kinetics: aerobic continuous culture experiments

Lovanh, Nanh; Hunt, Craig S.; Alvarez, Pedro J. J.

doi:10.1016/s0043-1354(02)00090-8

Cited by 81 publications

(58 citation statements)

References 23 publications

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“…1,2 Functional changes may include preferential degradation of more labile carbon substrates over other biodegradable and more toxic compounds present (e.g., benzene (B), toluene (T), xylene (X), and ethylbenzene (E)). 3 A growing body of work has examined the influence of ethanol on the natural attenuation and biodegradation of BTEX under both aerobic and anaerobic conditions [4][5][6][7][8] These studies suggest that simultaneous introduction of ethanol and BTEX will result in decreased BTEX attenuation rates and longer contaminant plumes. The majority of previous results, however, are based on microcosm or column experiments 4,5,8 or on small sets of observational field data comparing contaminated aquifers exposed or not exposed to ethanol.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ethanol on Microbial Community Structure and Function During Natural Attenuation of Benzene, Toluene, and o-Xylene in a Sulfate-reducing Aquifer

Feris

Mackay

Sieyes

et al. 2008

Environ. Sci. Technol.

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SynopsisIn a continuous release field experiment, ethanol altered microbial community structure/function, lowered the redox state, and slowed biodegradation of coreleased BTo-X in an anaerobic aquifer. AbstractEthanol (EtOH) is a commonly used fuel oxygenate in reformulated gasoline and is an alternative fuel and fuel supplement. Effects of EtOH release on aquifer microbial ecology and geochemistry have not been well characterized in situ. We performed a controlled field release of petroleum constituents (benzene (B), toluene (T), o-xylene (o-X) at ∼1-3 mg/L each) with and without EtOH (∼500 mg/L). Mixed linear modeling (MLM) assessed effects on the microbial ecology of a naturally sulfidic aquifer and how the microbial community affected B, T, and o-X plume lengths and aquifer geochemistry. Changes in microbial community structure were determined by quantitative polymerase chain reaction (qPCR) targeting Bacteria, Archaea, and sulfate reducing bacteria (SRB); SRB were enumerated using a novel qPCR method targeting the adenosine-5′-phosphosulfate reductase gene. Bacterial and SRB densities increased with and without EtOH-amendment (1−8 orders of magnitude). Significant increases in Archaeal species richness; Archaeal cell densities (3-6 orders of magnitude); B, T, and o-X plume lengths; depletion of sulfate; and induction of methanogenic conditions were only observed with EtOH-amendment. MLM supported the conclusion that EtOH-amendment altered microbial community structure and function, which in turn lowered the NOT THE PUBLISHED VERSION; this is the author's final, peer-reviewed manuscript. The published version may be accessed by following the link in the citation at the bottom of the page.

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Section: Introductionmentioning

confidence: 99%

Effect of Ethanol on Microbial Community Structure and Function During Natural Attenuation of Benzene, Toluene, and o-Xylene in a Sulfate-reducing Aquifer

Feris

Mackay

Sieyes

et al. 2008

Environ. Sci. Technol.

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“…Supply of ethanol at low concentrations (1.5 mg/L) was found to be beneficial for benzene degradation due to enhanced growth of the degraders (Lovanh et al, 2002). When ethanol was present in large quantities (> 5 mg/L), Lovanh et al (2002) noticed inhibition of benzene degradation due to high consumption of electron acceptors and other necessary nutrients during ethanol degradation. This was not the case in the present study as sufficient amount of nutrients were constantly supplied through the influent.…”

Section: Twenty Five Day Benzene Absence Periodmentioning

confidence: 99%

“…Ethanol presence could have either maintained or increased the biomass in the PRBBs (Lovanh et al, 2002). However, the retained bacterial culture preferred toluene over benzene.…”

Section: Bacterial Community Examinationmentioning

confidence: 99%

In situ Groundwater Remediation Using Enricher Reactor – Permeable Reactive Biobarrier

Kasi¹,

McEvoy²,

Padmanabhan³

et al. 2010

proc water environ fed

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Permeable reactive biobarrier (PRBB) is a flow-through zone where microorganisms degrade contaminants in groundwater. Discontinuous presence of contaminants in groundwater causes performance loss of a PRBB in removing the target contaminant. A novel enricher reactor (ER) -PRBB system was developed to treat groundwater with contaminants that reappear after an absence period. ER is an offline reactor for enriching contaminant degraders, which were used for augmenting PRBB to maintain its performance after a period of contaminant absence. The ER-PRBB concept was initially applied to remove benzene that reappeared after absence periods of 10 and 25 days. PRBBs without ER augmentation experienced performance losses of up to 15% higher than ER-PRBBs.The role of inducer compounds in the ER to enrich bacteria that can degrade a mixture of benzene, toluene, ethylbenzene, and xylene (BTEX) was investigated with an objective to minimize the use of toxic chemicals as inducers. Three inducer types were studied: individual BTEX compounds, BTEX mixture, and benzoate (a non toxic and a common intermediate for BTEX biodegradation). Complete BTEX removal was observed for degraders enriched on all three inducer types; however, the removal rates were dependent on the inducer type. Degraders enriched on toluene and BTEX had the highest degradation rates for BTEX of 0.006 to 0.014 day -1 and 0.006 to 0.012 day -1 , respectively, while degraders enriched on benzoate showed the lowest degradation rates of 0.004 to 0.009 day -1 .The ER-PRBB technique was finally applied to address the performance loss of a PRBB due to inhibition interactions among BTEX, when the mixture reappeared after a iv 10 day absence period. The ER-PRBBs experienced minimal to no performance loss, while PRBBs without ER augmentation experienced performance losses between 11% and 35%. Presence of ethanol during the BTEX absence period increased the performance loss of PRBB for benzene removal. PRBBs augmented with degraders enriched on toluene alone overcame the inhibition interaction between benzene and toluene indicating that toluene can be used as a single effective inducer in an ER. The ER-PRBB was demonstrated to be a promising remediation technique and has potential for applications to a wide range of organic contaminants.v ACKNOWLEDGEMENTS

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“…The preferential degradation of these compounds (or other common substrates that are degraded through central metabolic pathways) appears to be related to catabolite repression and metabolic flux dilution, which hinder the rate of BTEX degradation per unit cell (Lovanh et al, 2002;Lovanh and Alvarez, 2004;Da Silva and Alvarez, 2010). Acetate accumulation during the anaerobic degradation of ethanol can also make the fermentative biodegradation of BTEX endergonic, thus hindering the thermodynamic feasibility of anaerobic natural attenuation (Corseuil et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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

Silva

Gómez

Alvarez

2013

Journal of Contaminant Hydrology

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Effect of ethanol on BTEX biodegradation kinetics: aerobic continuous culture experiments

Cited by 81 publications

References 23 publications

Effect of Ethanol on Microbial Community Structure and Function During Natural Attenuation of Benzene, Toluene, and o-Xylene in a Sulfate-reducing Aquifer

Effect of Ethanol on Microbial Community Structure and Function During Natural Attenuation of Benzene, Toluene, and o-Xylene in a Sulfate-reducing Aquifer

In situ Groundwater Remediation Using Enricher Reactor – Permeable Reactive Biobarrier

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

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