Microalgae-based wastewater treatment: Advances and challenges in membrane harvesting technologies

Current wastewater treatment methodologies are limited by the high costs and complexities involved in efficiently removing nitrogen and phosphorus. Microalgae-based treatment has emerged as a superior alternative, providing sustainable nutrient recovery while producing valuable biomass suitable for bio-refining. This review explores recent advancements in microalgae-based wastewater treatment, with a focus on membrane harvesting technologies. Each wastewater type offers potential for microalgae cultivation, but optimizing growth requires careful control of nutrient content, contaminants, and physical conditions. Key factors include optimizing C/N and N/P ratios for different microalgae species and utilizing pretreatment methods to reduce microbial load and inhibitory components. Tailored treatments and innovative approaches are crucial to unlocking the full potential of these systems. While membrane processes are efficient and straightforward to operate, membrane fouling remains a significant challenge. This review highlights advanced strategies to mitigate fouling, such as surface modifications, hybrid membrane systems, and novel low-energy processes like solid–liquid fluidization. The integration of membrane technologies with bioenergy production is presented as a promising pathway to enhance sustainability and economic viability. Despite notable progress, continued research and technological innovation are essential to overcome fouling and energy consumption challenges, ensuring scalability and cost-effectiveness in real-world applications of microalgae-based wastewater treatment.