Bacterial inactivation kinetics, regrowth and synergistic competition in a photocatalytic disinfection system using anatase titanate nanofiber catalyst

Meng Nan Chong, Bo Jin, Huaiyong Zhu, Chris Saint

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Abstract

This work studied the inactivation kinetics, bacterial regrowth and synergistic competition in the photocatalytic disinfection of a sewage isolated Escherichia coli (ATCC 11775) in an annular slurry photoreactor (ASP) system using anatase titanate nanofibers catalyst (TNC). The inactivation performance and disinfection kinetics of the TNC-ASP system were investigated with respect to operation conditions: TNC loading, pH, aeration rate and inoculums size. At the optimum conditions, a 99.999% inactivation of 7 × 106 CFU mL-1 E. coli was achieved in 60 min. The modified Hom model was used to perfectly-fit the sigmoid-shaped disinfection kinetic profile. The residual disinfecting effect was evaluated by post-irradiation Fenton reaction. It was found that the 1.0 mg L-1 Fe2+ in conjunction with low chemical oxygen demand (COD) was able to initiate the post-photocatalytic Fenton reaction, where substantial bacterial regrowth was suppressed after 24 h treatment. Studies on the synergistic effect of COD concentration on the inactivation and the bacterial regrowth potential revealed that the E. coli could regrowth at a COD concentration over 16 mg L-1. Thus, significant removal of COD has to be ensured in a photocatalytic disinfection process to successfully maintain the biostability of the treated water.

Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume214
Issue number1
DOIs
Publication statusPublished - 5 Jul 2010
Externally publishedYes

Keywords

  • Annular reactor
  • Bacterial inactivation
  • E. coli
  • Fenton reaction
  • Nanofibers
  • Photocatalysis
  • Post-disinfection
  • Synergistic competition
  • TiO

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