Advances in immobilized microbial technology and its application to wastewater treatment: A review

[Display omitted] •The advantages and disadvantages of immobilization carriers for wastewater applications are reviewed.•Composite carriers, nanocarriers, metal-organic frameworks, and biochar have potential applications in wastewater treatment.•Layer-by-layer self-assembly and electrostatic spinning methods have great potential for future development.•The immobilization of Anammox bacteria and aerobic denitrifying bacteria can enhance nitrogen removal from wastewater.•Future trends and research directions of immobilized microbial technology are summarized. The use of immobilized microbial technology in wastewater treatment has drawn extensive attention due to its advantages of high colony density, rapid reaction speed, and good stability. Immobilization carriers are the core of immobilization technology. This review summarizes the types of immobilization carriers and their advantages and disadvantages, focusing on the potential for utilizing novel immobilization carriers (composite carriers, nanomaterials, metal–organic frameworks (MOFs), and biochar materials) in wastewater applications. The basic principles and technical advantages and disadvantages of novel immobilization methods (layer-by-layer self-assembly (LBL) and electrostatic spinning) are then summarized. Additionally, the research progress and application characteristics of immobilized anaerobic ammonia oxidizing (Anammox) and aerobic denitrifying (AD) bacteria for enhanced wastewater nitrogen removal are discussed. Finally, the current challenges of immobilized microbial technology are discussed, and its future development trends are summarized and prospected. This review provides guidance and theoretical support for the practical engineering application of immobilized microbial technology.