This text offers a systematic review and summary on the development of biological nutrient removal (BNR) in fundamental research and practical applications. It provides the latest information about state-of-the-art BNR technology in wastewater treatment, including new filtration and membrane systems. This guide presents extensive coverage of several basic BNR biochemical processes (nitrification, denitrification, and EBPR), three types of BNR processes (conventional single sludge systems, recently developed two sludge systems, and MBR BNR systems), recently widely used process modeling and simulation technology, and key aspects of process design, operation, and control.