Development of a control algorithm for air-scour reduction in membrane bioreactors for wastewater treatment

Authors

  • Giuliana Ferrero,

    1. ICRA (Catalan Institute for Water Research), Scientific and Technological Park of the University of Girona, H2O Building, c/Emili Grahit 101, E17003, Girona, Spain
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  • Hector Monclús,

    1. Laboratory of Chemical and Environmental Engineering (LEQUiA), Environmental Institute, University of Girona, Girona, E1707, Spain
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  • Gianluigi Buttiglieri,

    1. ICRA (Catalan Institute for Water Research), Scientific and Technological Park of the University of Girona, H2O Building, c/Emili Grahit 101, E17003, Girona, Spain
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  • Sara Gabarron,

    1. Laboratory of Chemical and Environmental Engineering (LEQUiA), Environmental Institute, University of Girona, Girona, E1707, Spain
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  • Joaquim Comas,

    1. Laboratory of Chemical and Environmental Engineering (LEQUiA), Environmental Institute, University of Girona, Girona, E1707, Spain
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  • Ignasi Rodríguez-Roda

    Corresponding author
    1. ICRA (Catalan Institute for Water Research), Scientific and Technological Park of the University of Girona, H2O Building, c/Emili Grahit 101, E17003, Girona, Spain
    2. Laboratory of Chemical and Environmental Engineering (LEQUiA), Environmental Institute, University of Girona, Girona, E1707, Spain
    • ICRA (Catalan Institute for Water Research), Scientific and Technological Park of the University of Girona, H2O Building, c/Emili Grahit 101, E17003, Girona, Spain.
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Abstract

BACKGROUND: Membrane bioreactors are used in an increasing number of wastewater treatment facilities because of their compactness and efficiency in solid-liquid separation, but energy requirements are still higher than other competitive technologies such as conventional activated sludge.

RESULTS: In this paper the development of an air-scour control algorithm based on short-term and long-term membrane permeability evolution is presented. An open loop calibration and partial validation was carried out in a semi-industrial scale pilot plant where manual changes in air-scour flow had been previously carried out. The control system was successfully tested in closed loop in an industrial scale pilot plant, defining a maximum daily air-scour decrease or increase of 6% of the air-scour recommended by membranes suppliers. An average air-scour saving of 13% and a maximum of 20%, calculated in terms of air flow saved, were achieved during the validation test without any apparent long-term effect on membrane permeability.

CONCLUSION: It was proven that the air-scour control system is an important tool capable of reducing operational costs in MBR systems. Copyright © 2011 Society of Chemical Industry

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