Effect of Solid Retention Time on Membrane Fouling In the Membrane Bioreactor Systems for Treating Synthetic Wastewater

In current years, the application of membrane bioreactor (MBR) instead of the conventional activated sludge process (CASP) is becoming more common. MBR has many advantages over the CASP such as high removal efficiency and the flexibility of operations. However, the major obstacle for MBRs is membrane fouling. Previous works showed that membrane fouling is related to the operating parameters such as HRT (Hazrati et al., 2016), sludge retention time (SRT), and sludge specifications (e.g. floc size, extracellular polymeric substance (EPS), soluble microbial product (SMP) and sludge viscosity) (Hazrati and Shayegan, 2016). It is well known that SRT is one of the important factors, which can change the state of biomass in an activated sludge system. Considering the aspects mentioned above, SRTs have significant effects on biological activity and membrane performance in MBR systems. In this study, a system was operated with synthetic wastewater. The main purpose of this study was to investigate the effect of SRT on specific biological activity and membrane fouling in a membrane bioreactor.