A pilot trial-based life cycle assessment of self-forming dynamic membrane bioreactor (SFDMBR) and comparative analysis with conventional treatment processes

Rapid urbanization has an increased urban wastewater discharge, necessitating the improvement of wastewater treatment plants (WWTPs) in terms of water quality and capacity. Conventional technologies, such as conventional activated sludge processes (CASPs) and membrane bioreactors (MBRs), face limitations like cost, environmental impact, and urban land space. This study investigates the feasibility of self-forming dynamic membrane bioreactor (SFDMBR) technology as a sustainable alternative for the retrofitting of WWTPs. A pilotscale SFDMBR test (around 100 m3/d) in a municipal WWTP aeration tank showed 68 % lower turbidity and 51 % lower total suspended solids than secondary sedimentation tank effluent, indicating a promising filtration performance. A comparative life cycle assessment (LCA) using data from the pilot test and a WWTP simulator revealed that retrofitting with SFDMBR resulted in 18-24 % lower cumulative energy demand (CED) and toxicities than CASP, with comparable global warming potential (GWP) and eutrophication potential. Compared to flat-sheet and hollow-fiber MBRs, SFDMBR had 23-87 % and 3-56 % lower GWP, CED, and toxicities. Sensitivity analysis demonstrated that SFDMBR technology maintained its environmental advantages over CASP even when increasing WWTP treatment capacities or when treating influents of varying strengths. These findings highlight SFDMBR technology's considerable environmental benefits as a viable and sustainable option for WWTP retrofitting.