A Review of Advanced Membrane Bioreactor (MBR) Technologies for the Removal of Contaminants of Emerging Concern (CECs) from Wastewater: Modified Photocatalytic Membrane and Microalgal Integration for Non-Potable Water Reclamation

As the use of products containing contaminants of emerging concern (CECs) is gradually amplifying through daily progression, the accumulation of these pollutants in wastewater continues to increase. The characteristics of these components, which persist in water for long periods, mean that they have various negative impacts on humans and the environment. Although many research studies are being conducted to find solutions for the removal of CECs from wastewater, there is still a gap regarding this issue. In order to promote green technology and sustainability, and to support sustainable development goals, this paper discusses a novel immobilised microalgae–photocatalytic membrane system for future research and further refinement. This system is expected to provide a deeper understanding of the mechanisms for CEC removal. The correlations between photocatalytic membranes, with up to 90% removal, and microalgae, with >99% removal of CECs, are elucidated. This review also focuses on system optimisation, including the selection of membrane materials and nanoparticles, the types of microalgae used and their efficiency, and the operating conditions. The proposed integrated system is conceptually aligned with the concept of the circular economy: the aim is to enhance CEC removal and produce high-quality treated water that could contribute to future non-potable water reclamation. However, its suitability has not been experimentally demonstrated and requires intensive study to prevent long-term impact of CECs on humans and the environment.