Long-term performance and fouling mitigation in industrial MBR systems: A systematic review of strategies and trade-offs

Membrane bioreactors (MBRs) are central to treating industrial wastewater, yet long-term operation is constrained by membrane fouling, which elevates operational and economic costs. While short-term anti-fouling strategies have been evaluated, it is unclear if they apply to long-term MBR operation. Web of Science and Scopus were searched to perform a systematic review of industrial studies evaluating performance >1 year up to 2025. Out of 1108 studies evaluated, 14 met this criterion. Sustained MBR performance without replacement was documented up to 18 years, with typical TMP slope reductions of 30–95% and COD removal efficiencies of 85–99% across included studies. Although strategies vary across industries, long-term effective MBR pretreatment included ozonation and anaerobic digestion. Tailored cleaning, such as using NaOCl for organic fouling and acids for scaling, reduced cleaning frequency by up to 60% relative to baseline. Operational adjustments (SRT ≈ 20–30 days, HRT > 20 h, nutrient control) further stabilized permeability and sustained effluent quality. There is a need for future industrial studies evaluating long-term performance across industries, as well as studies on emerging artificial intelligence-based monitoring strategies. The review identifies pragmatic strategies for operators and decision-makers across industries to sustain MBR performance and reduce costs in real-world applications.