Wastewater treatment represents a continuous challenge for engineers, environmental scientists and regulators. Today, an increasing number of new contaminants are being found such as pharmaceuticals, personal care products, and nanomaterials. In this book, the authors present current research in the study of the biological methods, technology and environmental impact of wastewater treatment processes. Topics include anaerobic membrane bioreactors for wastewater treatment; ecotoxicological approaches to assess wastewater's environmental impact to saltwater; EBPR for wastewater treatment; innovative sequencing batch reactors for industrial wastewater treatment; PAHs in the water environment; and cationic tannins as a coagulatnt/flocculant agent.