## 3 High Retention Membrane bioreactors (HRMBR)
### Osmotic Membrane bioreactor (OMBR) for OMPs Removal
\begin{tabular}{c} **Flux** \\ **(LMH)** \\ \end{tabular}  & \begin{tabular}{c} **Salinity** \\ **(g/L)** \\ \end{tabular}  & \begin{tabular}{c} **Micropollutants** \\ **Investigated** \\ \end{tabular}  & \ \begin{tabular}{c} **\%** \\ **Removal** \\ \end{tabular}  & **References** \\ \hline \hline \multirow{9}{*}{
\begin{tabular}{c} **Wastewater** \\ **Wastewater** \\ **Node, DS-1.5 M** \\ **NaCl, MLSS** \\ **3.4-3.7 g/L** \\ **NaCl, MLSS** \\ **3.4-3.7 g/L** \\ **NaCl, MLSS** \\ **NaCl,  
that \(>\)90% biodegradation was accomplished for all hydrophobic OMPs in OMBR-RO system [5]. [PERSON] et al. (2015b) in their MF-OMBR work also noticed that out of 30 OMPs eleven hydrophobic OMPs were efficiently removed in OMBR and MF-MBR system, whereas adsorption onto the sludge was considered a dominant removal mechanism. Furthermore, authors report that OMPs such as salicylic acid (hydrophilic OMP) and bisphenol A and octocrylene (hydrophobic OMP) showed poorer removal by forward osmosis membrane in OMBR than MF-MBR which could be linked to the cake enhanced concentration polarization due to foulants cake layer on the membrane surface. Indeed, detailed investigations for such phenomena need to be performed to confirm such results [76]. To achieve efficient biodegradation of C and N atoms, conventional activated sludge (CAS) system was separated into anaerobic, anoxic and aerobic compartments operated in different sequences. Usually multiple reactor configuration is the most common however single-compartment with varying redox conditions may be used to save space. In single reactor configuration, partition was made by inserting baffles to divide reactor in anoxic and oxic zones, also by setting aeration cycle time anoxic and aerobic conditions can be achieved in a single bioreactor. This unique redox condition leads to entirely different microbial consortia capable to accomplish carbon and nitrogen biodegradation and stripping-off carbon (carbon dioxide (CO\({}_{2}\))) and nitrogen (e.g., nitrogen (N\({}_{2}\)) and nitrous oxide (N\({}_{2}\)O)) gases [3]. [PERSON] et al. (2018) recently examined a novel baffled osmotic membrane bioreactor-microfiltration integrated process to study the removal of three OMPs employing inorganic and organic draw solutes. Model OMPs showed better removal with organic draw solutes and in general baffled OMBR showed very high total nitrogen (\(>\)85%) and excellent OMP removal. Atrazine, a very refractory molecule and pesticide compound, had shown enhanced removal under unique redox environment under extended anoxic cycle time of 1.5 h that may have developed very different microbial community responsible for different enzyme secretion [100]. [PERSON] et al. (2017) evaluated removal of 30 different hydrophilic and hydrophobic OMPs in OMBR employing two different CTA and TFC membranes. The authors report that TFC membrane outperformed CTA membrane for OMP rejection and reduced load on combined RO process. Moreover, \(>\)95% removal was observed for hydrophobic OMPs with both CTA and TFC membranes. However, \(<\)80% removal was noted for hydrophilic OMPs such as clofibric acid, fenopro, primidone, diclofenac, propoxur, carbamazepine, atrazine and amertime. The authors further linked this to the recalcitrant EWGs (-CI, -NO\({}_{2}\)) in hydrophilic OMPs than EDGs (-NH\({}_{2}\) and -OH) in hydrophobic OMPs [6]. Similarly, [PERSON] et al. (2018) observed that aquaporin FO membrane showed robustness and stability when integrated with activated sludge treatment. The authors report that OMBR achieved more than 80% removal for hydrophilic and refractory OMPs such as salicylic acid, ketoprofen, naproxen, metronidazoleze, ibuprofen, gemfibrozil, pentachlorophenol, DEET and amertime. However, certain OMPs such as clofibric acid, fenopro, rimidone, carbamazepine and atrazine showcased poor removals of less than 30% [104]. [PERSON] et al.