Perchlorate reduction from a highly contaminated groundwater in the presence of sulfate-reducing bacteria in a hydrogen-fed biofilm

Authors

  • Aura Ontiveros-Valencia,

    1. Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, 1001 South McAllister Ave. Tempe, Arizona
    2. School of Sustainability, Arizona State University, Tempe, Arizona
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  • Youneng Tang,

    1. Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, 1001 South McAllister Ave. Tempe, Arizona
    2. University of Illinois at Urbana-Champaign, Urbana, Illinois
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  • Rosa Krajmalnik-Brown,

    1. Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, 1001 South McAllister Ave. Tempe, Arizona
    2. School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona
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  • Bruce E. Rittmann

    Corresponding author
    1. Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, 1001 South McAllister Ave. Tempe, Arizona
    2. School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, Arizona
    • Correspondence to: B. E. Rittmann

      telephone: +1-480-727-0434

      fax: 1-480-727-0889

      e-mail: rittmann@asu.edu

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ABSTRACT

We used a hydrogen (H2)-based biofilm to treat a groundwater contaminated with perchlorate (ClO4) at ∼10 mg/L, an unusually high concentration. To enhance ClO4 removal, we either increased the H2 pressure or decreased the electron-acceptor surface loading. The ClO4 removal increased from 94% to 98% when the H2 pressure was increased from 1.3 to 1.7 atm when the total acceptor surface loading was 0.49 g H2/m2 day. We then decreased the acceptor surface loading stepwise from 0.49 to 0.07 g H2/m2 day, and the ClO4 removal improved to 99.6%, giving an effluent ClO4 concentration of 41 µg/L. However, the tradeoff was that sulfate (SO42−) reduction occurred, reaching 85% conversion at the lowest acceptor surface loading (0.07 g H2/m2 day). In two steady states with the highest ClO4 reduction, we assayed for the presence of perchlorate-reducing bacteria (PRB), denitrifying bacteria (DB), and sulfate-reducing bacteria (SRB) by quantitative polymerase chain reaction (qPCR) targeting characteristic reductases. The qPCR results documented competition between PRB and SRB for space within the biofilm. A simple model analysis for a steady-state biofilm suggests that competition from SRB pushed the PRB to locations having a higher detachment rate, which prevented them from driving the ClO4 concentration below 41 µg/L. Biotechnol. Bioeng. 2013;110: 3139–3147. © 2013 Wiley Periodicals, Inc.

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