Performance of a hybrid membrane bioreactor treating a low strength and alkalinity wastewater

• Published in: Process biochemistry (1991) Vol. 66; pp. 176 - 182
• Main Authors: Silva-Teira, Alvaro, Vázquez-Padín, José Ramón, Weiler, Rosa, Fernández-González, Roberto, Rogalla, Frank, Garrido, Juan Manuel
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01-03-2018; Elsevier BV
• Subjects: Alkalinity; Biofilms; Bioreactors; Denitrification; Fouling; Granular materials; Hybrid; Low alkalinity; MBR; Membrane permeability; Membrane processes; Moving bed bioreactor; Municipal wastewater; Nitrogen removal; Permeability; pH effects; Raw wastewater; Studies; Variability; Wastewater; Wastewater treatment; Water treatment; Hybrid; Moving bed bioreactor; Permeability; MBR; Municipal wastewater; Low alkalinity
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2017.12.015

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•A low alkalinity played an essential role on the system’s performance.•Influent variability limited denitrification especially in valley COD stages.•Membrane filtration performed remarkably even when severe conditions were present.•Biowin accurately predicted the steady state of the hybrid system.
A pilot-scale Hybrid Membrane Bioreactor (HMBR) containing both suspended biomass and biofilm was tested for the treatment of a low strength municipal wastewater. The wastewater fed was characterized by a high variability throughout the day, low BOD5/TN ratio and low alkalinity (302 ± 52 mgCaCO3/L). For limiting membrane fouling, an innovative abrasive granular material has been proven in the Microdyn-Nadir membrane. Permeability ranged from 126 to 291 L/(h m2 bar) during the operational period, achieving a maximum flux of 24 L/(m2 h). A low BOD5/TN ratio of the raw wastewater, led to insufficient denitrification, with an average nitrogen removal of 49%. This fact, in turn, caused a decrease in the pH due to the lack of alkalinity. This study underlined that wastewaters characterized by high variability throughout the day, low BOD5/TN ratio and/or low alkalinity content require carefully design of the MBR systems. It was shown that a low pH in the HMBR led to a strong membrane fouling increasing cake resistances.