A nano-Al2O3 modified polypropylene hollow fiber membrane with enhanced biofilm formation in membrane aerated biofilm reactor application

Membrane Aerated Biofilm Reactor (MABR) stands out as an innovative technology for wastewater treatment. However, biofilm formation poses a significant challenge in its implementation. Surface modification emerges as a viable strategy to enhance biofilm development. In this study, biofilm formation was effectively promoted by coating polydopamine (PDA) and loading aluminum oxide nanoparticles (Al2O3 NPs) onto a polypropylene (PP) hollow fiber membrane, aiming to improve wettability and potential. Results from the bacterial attachment assay demonstrated a significantly higher bacterial attachment rate on the membrane loaded with Al2O3 NPs compared to PDA/PP and PP membranes. A comprehensive investigation into the MABR process was conducted, assessing both short-term and long-term (72 days) performance. In the short-term process, the Al2O3 NPs-PDA modified membrane exhibited superior removal efficiency for chemical oxygen demand (COD), ammonium nitrogen (NH4+-N), and total nitrogen (TN) compared to other membranes. Transitioning to the long-term process, the start-up period for the Al2O3 NPs(10)-PDA/PP membrane was notably shortened to 27 days, surpassing the start-up times of PP and PDA/PP membranes by 13 and 5 days, respectively. Throughout the long-term operation, when the influent COD, NH4+-N, and TN concentrations increased, the Al2O3 NPs-PDA/PP membrane consistently maintained removal efficiency above 95%, 98%, and 85% for COD, NH4+-N, and TN, respectively, demonstrating excellent resistance to shock loading.