Current Status and Future Prospects of Membrane Bioreactors (MBRs) and Fouling Phenomena: A Systematic Review

Abstract

Membrane bioreactors (MBRs) have been widely used for municipal and industrial wastewater treatment around the world due to their advantages, which include higher efficiency, smaller footprint, and lower sludge production over other conventional activated sludge (CAS) processes. However, membrane fouling that results from physicochemical interactions between the membrane and the components of the mixed liquor still remains the most challenging matter preventing the broad application of MBR technology. Recently, a considerable number of experimental and modelling investigations have been conducted concerning MBRs and membrane fouling. Despite the development of low‐fouling membrane systems, more research and engineering activities with a focus on surface modification, wastewater specifications, pre‐treatment and treatment conditions, and efficient fouling control and remedy strategies are still needed to minimize the probability of the occurrence of fouling. It is vital to investigate important aspects of the characterization and mechanisms of the fouling phenomenon to find reliable and long‐term solutions. This review provides a detailed survey of the main aspects of the MBR processes, configurations, advantages and disadvantages, fouling phenomenon, and fouling control strategies in MBRs. Past research and engineering activities in this area are critically reviewed such that pros and cons of recent developments in fouling inhibition and mitigation approaches are also discussed. The main practical and theoretical challenges for the effective utilization of MBRs in various municipal and industrial sectors are then addressed. At the end, we offer useful practical guidelines and recommendations for the better design and operation of MBRs in industrial and public communities.

Fouling Mitigation by Cationic Polymer Addition into a Pilot-Scale Anaerobic Membrane Bioreactor Fed with Blackwater

“…Furthermore, some studies suggest that floc size had no effect on fouling mitigation, or even had a negative effect, which the author attributed to a decrease in the extracellular polymeric substances (EPS) [ 49 ] and to changes in the structure of the flocs [ 19 ]. Nevertheless, the Carman-Kozeny equation and thermodynamic approaches suggest that floc size directly affects membrane fouling, and that small flocs have a stronger effect than large flocs [ 40 , 41 ]. Therefore, floc size might have a significant effect on membrane fouling for small flocs, whereas further increasing the size of already large particles might have a negligible effect on fouling mitigation.…”

Electrokinetic Membrane Bioreactors

“…Due to the high cost and biomass separation issues of the conventional treatment processes, MBR was developed to overcome the bottlenecks of the conventional processes. The general advantages of MBR technology over the conventional processes are high effluent quality, low sludge production, easy construction, Small operational volume needed (due to the combination of the membrane filtration and biological treatment), low energy consumption, and low cost [6]. In treatment processes such as flat bioreactor and activated sludge, microalgae can be washed out which causes further cost to cultivate and increase the microalgae population [7].…”

“…Therefore, the presence of the membrane filtration in MBR technology helps this process to prevent the washout issue. Despite the fact that the MBR technology has been widely used for municipal and industrial wastewater treatment in full-scale plants, membrane fouling is a major challenge that hinders a wide application of MBRs [6]. The fouling of membranes in MBRs has received much attention as a result of the major role of the membrane's life span in the performance of MBRs [8,9].…”

A critical review on nanomaterials membrane bioreactor (NMs-MBR) for wastewater treatment

“…Membrane bioreactors (MBRs) have proven to be one of the most effective technologies globally for treating wastewater from different sources [1][2][3] . In MBRs operation, wastewater treatment is carried out via a combination of biological unit (for the biodegradation of waste streams) and membrane filtration unit (for the separation of treated water from biosolids using membrane module).…”