Applicability of Microaerobic Technology to Enhance BTEX Removal from Contaminated Waters
As the addition of low concentrations of oxygen can favor the initial degradation of benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds, this work verified the applicability of the microaerobic technology to enhance BTEX removal in an anaerobic bioreactor supplemented with high and low co-substrate (ethanol) concentrations. Additionally, structural alterations on the bioreactor microbiota were assessed throughout the experiment. The bioreactor was fed with a synthetic BTEX-contaminated water (~ 3 mg L−1 of each compound) and operated at a hydraulic retention time of 48 h. The addition of low concentrations of oxygen (1.0 mL min−1 of atmospheric air at 27 °C and 1 atm) assured high removal efficiencies (> 80%) for all compounds under microaerobic conditions. In fact, the applicability of this technology showed to be viable to enhance BTEX removal from contaminated waters, especially concerning benzene (with a 30% removal increase), which is a very recalcitrant compound under anaerobic conditions. However, high concentrations of ethanol adversely affected BTEX removal, especially benzene, under anaerobic and microaerobic conditions. Finally, although bacterial community richness decreased at low concentrations of ethanol, in general, the bioreactor microbiota could deal with the different operational conditions and preserved its functionality during the whole experiment.
KeywordsMonoaromatics Contaminated water Anaerobic treatment Microaerobic treatment Microaeration
The authors would like to thank Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (Process 481270/2010-8), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES (Process PNPD 3022/2010), and Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico – Funcap (Process 078.01.00/09) for the research grants and financial support.
Compliance with Ethical Standards
The authors indicate no potential conflicts of interest.
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