Treatment of cosmetic industry wastewater by submerged membrane bioreactor with consideration of microbial community dynamics

• Aerobic submerged MBR was proposed for the treatment of cosmetic wastewater.
• High and consistent removal of COD and anionic surfactants was achieved.
• Organic loading increase significantly affected microbial community dynamics.
• The study revealed that most organics in the influent were removed by MBR process.

A pilot scale aerobic submerged membrane bioreactor (MBR) for treating cosmetic wastewater was operated for 205 days. During the operation, increasing organic loading rates (OLR) were applied in the MBR. The effects of the applied OLR (from 0.25 to 2 g COD l-1 d-1) were evaluated regarding chemical oxygen demand (COD) and anionic surfactant (AS) removal efficiencies. At an optimal volumetric OLR of 1.52 g COD l-1 d-1, the MBR achieved the highest COD and AS removal efficiencies (83.73% and 98.13%, respectively). The influence of the OLR on filtration performance was assessed, including GC/MS analysis of raw and treated wastewater. The denaturing gradient gel electrophoresis (DGGE) analysis was used to monitor the dynamics of the bacterial communities inside the bioreactor. Major bands of DGGE patterns of sludge samples were further sequenced. Phylogenetic analysis indicated that the majority of the sequences obtained were affiliated with α-Proteobacteria, Actinobacteria and Fimicutes.