Improvement of denitrifying reaction rate by enhanced substrate transport within a cell-immobilized space by electrophoresis

Satoshi Tsuneda, Shuichi Kaku, Hiroshi Hayashi, Satoshi Ohgushi, Akihiko Terada, Akira Hirata

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    In order to improve the microbial reaction rate within a cell-immobilized space, this study experimentally investigated enhanced substrate transport by electrophoresis of a specific ion. Batch-mode and continuous feeding denitrification tests were carried out in an autotrophic denitrifying bioreactor using sulfur-oxidizing microbes as a model system. Seed sludge and powdered sulfur were immobilized on fibrous carrier medium, and an electric field was applied through the cell-immobilized zone via inert electrodes on both sides of vessel. In batch-mode denitrification tests, nitrogen removal rate reached 1.99 g-N·m-3·h-1 when the electric field of 18V was reversed at intervals of 30min, as compared with 0.40g-N·m -3·h-1 when the electric field was not applied. These findings demonstrated that the denitrification rate was increased by promoting the transport of NO3 - ions across the cell-immobilized zone by electrophoresis. In addition, no reduction of NO 3 - to NO2 - occurred, indicating that decrease of nitrogen compound was due to biological reaction. Mathematical simulation analysis using a model involving Monod-type reaction kinetics and the Stokes formula for NO3 - mobility was in general agreement with the experimental results. The results of the continuous feeding test also indicated that electrophoresis improved the nitrogen removal rate.

    Original languageEnglish
    Pages (from-to)507-513
    Number of pages7
    JournalKagaku Kogaku Ronbunshu
    Issue number6
    Publication statusPublished - 2006



    • Bacterial cell immobilization
    • Biological wastewater treatment
    • Denitrification
    • Electrophoresis
    • Fibrous slag

    ASJC Scopus subject areas

    • Materials Science (miscellaneous)

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