### Membrane bioreactors in Organic Micropolultants Removal  
Conventional wastewater treatments targeting OMP removal face challenges with possible human health risk and risk to the environment [36; 37]. The most widely utilized physical and chemical treatment processes are very financially demanding [38]. Current WWTPs are not designed to eliminate or degrade OMPs completely, many of these OMPs can pass through the treatment system and enter into the natural aquatic system because of their persistence [39; 40]. The presence of refractory OMPs and their biodegradation by-products adversely affects biodegradation potential of bacteria present in activated sludge [34]. In addition, OMPs concentrations are uncertain in sewage and conventional wastewater treatment facilities are unable to efficiently remove OMPs to the extent for reuse applications [2]. For example, commonly detected OMPs such as ibuprofen showed biodegradable removal of 75% whereas Estrone (E1) and 17-\(\alpha\)-Ethinyl estradiol (EE2) achieved 83% and 44% removal [41]. Furthermore, advanced OMP removal or destruction options include adsorption or ion exchange using activated carbon and ion exchange resins, ultraviolet (UV) disinfection and advanced oxidation processes (AOP) such as hydrogen peroxide oxidation, electrochemical advanced oxidation processes (EAOPs) such as Anodic oxidation (AO) and electro-Fenton (EF) [42] and photocatalytic degradation. However these processes involve high capital and energy costs and also require disposal of highly contaminated exhausted sorbent or problematic residues [33]. Further, membrane-based treatment processes such as membrane bioreactor, reverse osmosis, nanofiltration, forward osmosis and membrane distillation are promising alternative for OMP removal. Microfiltration (MF)/ultrafiltration (UF) MBRs are techno-economically feasible and a most promising option in wastewater treatment. In MBRs, flatsheet or hollowfiber (HF) membranes are immersed into a bioreactor to achieve excellent and consistent micropollutant removal, compared to conventional activated sludge systems [3; 14; 18; 43; 44; 45]. The worldwide suppliers and key players of MBRs include SUEZ Water Technologies & Solutions (formerly GE Water & Process Technologies) (France), Kubota (Japan), Beijing Origin Water Technology (China), Evoqua Water Technologies (US), Mitsubishi Chemical Aqua Solutions (Japan), Toray Industries (Japan), CITIC Envirotech Ltd. (Singapore), Koch Membrane Systems (US), Alfa Laval (Sweden), Triqua International (Netherlands), Veolia (France) and Newterra Canada ([[https://www.Marketsandmarkets.com/Market-Reports/membrane-bioreactor-market-484.html](https://www.Marketsandmarkets.com/Market-Reports/membrane-bioreactor-market-484.html)]([https://www.Marketsandmarkets.com/Market-Reports/membrane-bioreactor-market-484.html](https://www.Marketsandmarkets.com/Market-Reports/membrane-bioreactor-market-484.html))). In 2017, SUEZ Water Technologies & Solutions acquired GE Water & Process Technologies, which strengthened the company's position in the water treatment field [46]. Kubota (Japan) was one of the early pioneers of the MBR concept and as of 2017 Kubota has supplied 5500 MBR systems of these 1500 MBR's are used in industrial wastewater treatment. Suez technology (formerly Zenon) produced four times better performance than Kubota in sewage treatment [47; 48]. Several literature reviews report the removal efficacies of MBR systems in both sewage and industrial waste treatment [49; 50; 51; 52]. However, this review aims at summarizing the recent advances, principally from 2015 to present, in standalone membrane biologic systems of MBRs and anaerobic MBRs (AnMBRs). This review further discusses factors affecting OMP removal by MBRs such as physicochemical properties of OMPs and operating parameters affecting MBR performance in OMP removal, referring to the most recent reports. Recently, high-retention membrane bioreactors (HRMBR) systems have been gaining momentum in wastewater treatment.