## 3 High Retention Membrane bioreactors (HRMBR)
### Membrane Distillation Bioreactor (MDBR) for OMPs Removal
 & **References** \\ \cline{2-6}  & **Operating Conditions** & **Feed** & **P permeate** & & \\ \hline \hline \multirow{9}{*}{
\begin{tabular}{c} **C.1** \\ **C.2** \\ **C.3** \\ **C.4** \\ **C.5** \\ **C.6** \\ **C.7** \\ **C.8** \\ **C.9** \\ **C.  
[PERSON] et al. (2014) concluded that both the salt accumulation and high temperature in bioreactor negatively influenced recalcitrant OMP removal in a membrane distillation-thermophilic bioreactor (MDBR). The hydrophilic compounds containing EWGs showed as low as 0 to 53% removal in thermophilic reactor due to their refractory nature during biologic process. Overall, MDBR process successfully removed more than 95% OMPs. However, all OMPs investigated were highly removed (>95%) by the MDBR system having more than 70% OMP removal by biodegradation. Membrane distillation contributed for certain OMPs rejection (42 to 94%) such as triclosan, fenoprop, atrazine, clofibric acid, diclofenac and carbamazepine. The authors further report that triclosan and octocrylene persistent hydrophobics were adsorbed on to the sludge led to better removal [75]. The synergy between the activated sludge and the MD membrane rejection contributed to 76% to complete removal of all 26 selected OMPs by the hybrid AnMBR-MD system. MD played a significant role in efficiently removing poorly degraded compounds from AnMBR such as primidone, ibuprofen, diclofenac and bisphenol A [83]. In another OMBR study, by integrating biologic process membrane distillation, the OMBR\(-\)MD combined system efficiently treated 30 OMPs successfully to extract reclaimed wastewater [97]. OMPs possessing EWG (e.g., -Cl\({}_{2}\), -NH\({}_{2}\) and -NO\({}_{2}\)) in the molar configuration are non-biodegradable to biologic process. The removal of these persistent OMPs such as carbamazepine, clofibric acid, fenoprop, primidone, diclofenac, carbamazepine and atrazine were less than 40% by conventional MBR. Despite their persistence, more than 60% of removal was achieved due to the extended retention of such refractory OMPs in the OMBR-MD hybrid system [97]. Significant fouling of the MD unit and continuous flux decline was noticed due to the complete retention of SMP and EPS fractions and the inorganic salts accumulated in the MD feed solution [83]. Another development is Laccase based enzymatic membrane bioreactor. Laccase can catalyze the degradation of a broad spectrum of pollutants including aromatic hydrocarbons, aliphatic amines and OMPs by using dissolved oxygen as a co-substrate. However, its larger-scale application is restricted by the lack of a reactor system, which can prevent washout of enzymes along with treated effluent [108]. In a recent study, [PERSON] et al. (2017) developed a novel membrane distillation-laccase based enzymatic membrane bioreactor (MD-EMBR) system capable to retain laccase for OMP removal evaluation. They achieved 80 to 99% removal by biologic process in the MD-EMBR for oxybenzene and diclofenac, respectively [20]. In MD-EMBR operation at short HRT (12 h) significantly enhanced biodegradation was achieved due to lacassae presence. Compared to conventional biologic process 40% higher removal was noted specifically for refractory compounds such as carbamazepine. Moreover, MD-EMBR could achieve better OMP removal as compare to UF-OMBR. This is due to the retention of lacassae by MD-EMBR however UF-EMBRs could not retain lacase [20, 108]. Similarly, in another such study, MD-EMBR achieved over 99% removal of some OMPs including 4-tert-octylphenol (pKH/logD = 0.98), octocrylene (pKH/log D = 1.21), 4-tert-butyl phenol (pKH/log D = 1.51), benzophenone (pKH/log D =1.83) and oxybenzene (pKH/log D = 2.1). This significant improvement can be attributed to the efficient degradation of these OMPs by laccase in MD-EMBR [108].