Disinfection of urban effluents using solar TiO2 photocatalysis: A study of significance of dissolved oxygen, temperature, type of microorganism and water matrix

I. García-Fernández, I. Fernández-Calderero, M. Inmaculada Polo-López, P. Fernández-Ibáñez

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    69 Citations (Scopus)

    Abstract

    The enhancement of current technologies used to treat polluted water is one of the most important challenges in water research. The application of physico-chemical treatments could reduce the load of chemical and biological pollutants present in WW reducing the pressure over water requirements, allowing the reclaim of the treated water. Advanced Oxidation Processes (AOPs) and, in particular, photocatalysis using titanium dioxide (TiO2) have shown a great potential for chemicals removal as well as for pathogens reduction in water. Moreover, the use of solar Compound Parabolic Collectors (CPC) reactors has been also shown to be very effective for water treatment purpose by solar photocatalysis. Nevertheless, the effects of some key parameters in photocatalytic disinfection have not been already investigated at pilot scale in solar reactors; like dissolved oxygen concentration, water temperature, water matrix composition and the type of microorganism. The roles of these parameters in photocatalytic processes are individually known for chemicals degradation, but their relative significance in water photocatalytic disinfection has been never studied at pilot scale. The aim of this work was to investigate the influence of these parameters on the disinfection efficiency using a solar 60 L-CPC reactor with suspended TiO2 (100 mg/L). The following variables were experimentally evaluated: injection of air in the reactor (160 L/h); different controlled temperatures (15, 25, 35 and 45 °C); two very different models of water pathogen, Escherichia coli (model of fecal water contamination) and Fusarium solani spores (a highly phytopathogenic fungus); and the chemical composition of the water comparing urban WW effluents (UWWE) and simulated urban WW effluent (SUWWE). The increase of water temperature (from 15 to 45 °C) had a benefit on the disinfection rate for both pathogens in all the experimental conditions evaluated. The air injection led to an important enhancement on the inactivation efficiency, which was stronger for F. solani spores, the most resistant microorganisms to TiO2 photocatalysis. The composition of the water matrix significantly affected the efficiency of the photocatalytic treatment, showing a better inactivation rate in SUWWE than for UWWE.
    Original languageEnglish
    Pages (from-to)30-38
    Number of pages9
    JournalCatalysis Today
    Volume240
    Issue numberPart A
    Early online date13 Apr 2014
    DOIs
    Publication statusPublished - 1 Feb 2015

    Bibliographical note

    The authors wish to thank the Spanish Ministry of Economy and Competitiveness for financial support under the AQUASUN project (reference: CTM2011-29143-C03-03). We also acknowledge the contribution of Elisa Ramos and Agustín Carrión in the experimental work. IGF would like to thank the University of Almería and CIEMAT-PSA for her PhD research grant.

    Keywords

    • Fusarium solani
    • Escherichia coli
    • TiO2 photocatalysis
    • WW treatment
    • Temperature
    • Dissolved oxygen

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