Up-Flow Anaerobic Sludge Bed Reactors for Sustainable Wastewater Management: Challenges, Innovations, and Future Directions

Abstract

The up-flow anaerobic sludge bed (UASB) reactor is a high-efficiency system capable of carrying out anaerobic digestion with shorter hydraulic retention times than traditional anaerobic digesters. This review highlights recent advancements in UASB reactor applications and key aspects such as microbial community dynamics and reactor hydrodynamics that could drive future developments. More specifically, this review evaluates the working principles of UASB reactors, explores strategies to optimize reactor efficiency, and examines technological advancements aimed at overcoming temperature constraints, managing emerging pollutants and micropollutants, and addressing scum accumulation, odor emission, and nutrient recycling challenges. Furthermore, it addresses concerns about the lack of a skilled workforce and energy loss in biomethane. The UASB reactor demonstrates high potential for enhancing global wastewater management while holding the promises of enhancing circular economic objectives, promoting efficient biogas utilization, and reducing greenhouse gas emissions.