Advances in Biological Wastewater Treatment Systems covers different recent advanced technologies, including green technologies, for biological wastewater treatment and wastewater reuse. These technologies involve novel biological processes and/or modified processes coupled with nanomaterials for improving the performance of the existing treatment processes. The book also describes treatment strategies for the current pollution from complex organic matter, nutrients, toxic substances, microplastics, and emerging micropollutants in different water resources. The treatment processes describe the recently developed technologies for wastewater treatment and reuse such as biological nutrient removal, bioreactors, photobioreactors, membrane bioreactors, wetlands, algae-bacteria process, natural treatments, integrated/hybrid biosystems. The novel biosystems include aerobic, anaerobic, facultative operation modes with various types of microorganisms. Key Features, Provides updated information on biological nutrient removal from wastewater, Includes anaerobic and aerobic wastewater treatment processes, Provides state-of-art information on design and operation of novel systems, including membrane bioreactors, Describes hybrid treatment processes