Incorporating Submerged MBR in Conventional Activated Sludge Process for Municipal Wastewater Treatment: A Feasibility and Performance Assessment

A pilot-scale submerged membrane bioreactor (MBR) was incorporated in a conventional activated sludge (CAS) process for more than 100 days in order to assess the feasibility and performance on the municipal wastewater treatment. After a stabilization period of 50 days, the MBR unit was operated under various temperatures (21 ± 4°C), mixed liquor suspended solids (MLSS) concentrations (14000 ± 1800 mg L-1), and different aeration intensities (3 to 6 m3 h-1). No significant deterioration in membrane flux was observed while operating with high biomass concentration. From the results, the removal of total suspended solids (TSS), chemical oxygen demand (COD), total phosphorus (TP) were enhanced using MBR. However, due to some limiting operational conditions, the total nitrogen (TN) removal was less efficient in MBR than in CAS. The MBR unit was 100% effective in removing E. coli and enterococcus, as well as noroviruses and adenovirus, making it more efficient than CAS. Also, the removal of most of the trace organic compounds (TrOCs) including personal care products, pharmaceuticals, steroid hormones and perfluorinated compounds were enhanced after the incorporation of MBR to CAS, as well as for many heavy metals in MBR.