Hybrid membrane technology with renewably derived biological and photocatalytic systems for wastewater treatment.

Numerous physical, chemical, and biological treatment strategies for removing pollutants from wastewater have been studied for several decades. Nevertheless, these methodologies possess some constraints. Since the early 2000s, membrane-based hybrid technology has been increasingly recognized and adopted due to advancements in manufacturing and casting methods, as well as membrane modification techniques. Membrane-based treatment technology, coupled with other semi-renewable treatment technologies such as advanced oxidation processes (photocatalysis), bioreactors, and hybrid membrane bioreactors, is adopted as an substitute to conventional wastewater treatment due to its ease of operation and superior performance. In this study, a thorough examination of these attractive hybrid technologies is conducted. Additionally, this study also assorted the stand-alone methods and techniques associated with membrane reactors, photocatalytic membrane reactors (PCMRs), and membrane bioreactors (MBRs). MBRs and PCMRs deliver effective and sustainable wastewater treatment by integrating biological processes or photocatalysis with membrane filtration, yielding high-quality effluents suitable for reuse. The benefits of these renewably derived integrations include their compact design, diminished sludge generation, and capacity for water recycling. However, fouling remains significant challenges, primarily resulting from foulant adherence, pore clogging, creation of a cake layer, and the temporal alogn with spatial changes in the structure of foulants are identified as key processes that contribute to fouling in PCMRS. The interaction of bacteria, membrane surfaces, and the secretion of extracellular polymeric substances are responsible for biofouling in MBRs. Incorporating AOP (photocatalysts) into MBR membranes presents a novel approach to mitigate fouling. The integration of catalysis and membrane filtration systems can stretch membrane lifespan, eliminate membrane surface contamination, and decompose organic pollutants simultaneously, thereby enhancing wastewater treatment efficiency. This study offers a thorough examination of contemporary research regarding membrane modification utilizing photocatalysts in MBR systems, emphasizing the prevailing challenges and future opportunities in this domain. Notwithstanding these possible benefits, studies aimed at enhancing MBR membrane effectiveness via photocatalysis are limited. To preserve the sustainability of this technology, it is imperative to consider key factors, including reactor configuration, kinetics, fouling processes, economic viability, and scaling challenges.