Overcoming carbamazepine (CBZ) recalcitrance in wastewater: A critical review of membrane bioreactor (MBR) performance, limitations, and optimization strategies

Carbamazepine (CBZ), a widely prescribed antiepileptic drug, is among the most persistent and frequently detected pharmaceutical contaminants in wastewater treatment plant (WWTP) effluents and surface waters worldwide. Due to its high chemical stability, low sorption affinity, and resistance to biodegradation, CBZ often passes through conventional treatment systems, posing ecological and human health risks. As a result, developing effective treatment strategies capable of removing CBZ from wastewater has become a critical priority, particularly through biological methods. Membrane bioreactors (MBRs) have gained significant attention as a promising method to remove recalcitrant compounds such as CBZ. This review critically examines the current state of MBR technology for CBZ removal, highlighting the influence of microbial communities, operational parameters, and membrane fouling dynamics on the treatment efficiency. Furthermore, integrated MBR systems, combining MBRs with advanced oxidation processes (AOPs), adsorption techniques, or biofilms, are evaluated for their potential to overcome the limitations of standalone MBR systems. Although these integrated approaches significantly improve CBZ removal and mitigate fouling, they face operational, economic, and scalability challenges. This review highlights the need for biologically optimized MBR configurations and the strategic enrichment of specialized microbial communities, including bacteria and fungi, capable of CBZ biotransformation. The findings offer a comprehensive perspective on advancing MBR-based technologies toward more efficient, resilient, and sustainable wastewater treatment systems.