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This study aims to investigate the effect of using Al2O3 nanoparticles (NPs) in membrane structure on the operation condition of the membrane bioreactor. To this end, alumina NPs as the high hydrophilic agents with an approximate size of 40 nm and a concentration of 0–3 wt.% were placed within the PAN polymeric membrane matrix structure with high hydrophilicity and high mechanical resistance over the others via the phase inversion method. Characterization of synthesized nanocomposite membranes was carried out by SEM analysis. In the presence of the alumina NPs, the porosity of the membranes improved. The water contact angle measurement confirmed the superior hydrophilicity of mixed PAN membranes compared to the pure polymeric membranes. The best nanocomposite membrane with better antifouling properties was selected to evaluate the MBR's performance in wastewater treatment and assessed in terms of the resistance, flux recovery, and COD removal rates. The result of a comparison with pure membrane showed that by increasing the Al2O3 amount up to 2wt.%, irreversible fouling resistance mitigated as much as 50%. Moreover, the flux recovery ratio was increased by 15%, and the COD removal rate was also raised as large as 16%. Our investigation illustrated that the presence of alumina NPs has improved the MBR performance and decreased the irreversible fouling resistance of the membrane. [ABSTRACT FROM AUTHOR]

Ensuring the effluent quality despite fluctuations in influent flow rate and organic load to municipal wastewater treatment plants is critical. This study investigated the performance of a membrane bioreactor (MBR) in handling hydraulic and organic loading shocks during wastewater treatment. The ability of the MBR to remove COD, BOD5, and turbidity from synthetic wastewater was evaluated at steady-state and after applying five levels of organic shock loads (1.5×-4×) and four levels of hydraulic shocks (1.2×-4.7×). Due to the short-term shock-loadings no discernible effect was observed on the mixed liquor suspended solids implying biological stability. The average COD removal in MBR exposed to organic and hydraulic shock loads was 93.8% and 94%, respectively, similar to average BOD5 removals of 94.4% and 93.6%. The membrane retained suspended particles well throughout the process. However, it became quickly fouled only by applying a strong hydraulic shock. The MBR guaranteed the quality of the effluent. [ABSTRACT FROM AUTHOR]