Membrane Bioreactors

Membrane Bioreactors (MBR) are a technology that combines elements from both the activated sludge process and membrane separation. In wastewater treatment, this commonly used approach involves identical procedures to conventional methods, eliminating the need for secondary or tertiary processes. Membrane bioreactors (MBR) utilize gentle filtration methods such as microfiltration or ultrafiltration, offering numerous advantages like exceptional effluent quality, a compact physical footprint, and precise differentiation between hydraulic retention time (HRT) and solids retention time (SRT). However, a notable downside is their considerable energy consumption. The MBR process primarily consists of two major steps: first, the degradation of contaminants by microorganisms within the bioreactor, and second, the separation of these microorganisms from the treated water using a membrane. MBRs can be employed in two different configurations: either as a submerged system or as a side-stream system. The submerged configuration has demonstrated greater cost-effectiveness when compared to the alternative setup. Another option is a biofilm membrane reactor (BF-MBR) that replaces the active sludge membrane bioreactor (AS-MBR). The BF-MBR holds promise in addressing the issue of membrane fouling resulting from high biomass concentrations. While it excels in eliminating soluble organic matter, it poses a significant risk of clogging when dealing with wastewater containing substantial particle matter. Anaerobic membrane bioreactors (AnMBR) represent a different type of MBR, known for their cost-effectiveness due to the absence of oxygen requirements and reduced sludge generation compared to aerobic methods. Alongside these mentioned configurations, there exists a diverse array of other MBR variations, including the osmotic membrane bioreactor (OsMBR), membrane distillation bioreactor (MDBR), and many more. This review delves into fundamental principles of MBR (Membrane Bioreactor) plants, followed by an exploration of recent advancements in various aspects related to MBR plants. It provides an in-depth analysis of the features of the bioreactor treatment procedure and conducts a thorough assessment of the membrane separation technique. Furthermore, it extensively discusses fouling as a major obstacle to the widespread use of MBR plants, along with the most recent approaches to reduce fouling.