Wastewater treatment is a process used to remove contaminants from the wastewater in order to convert it into an effluent that can be returned to the water cycle. Some common wastewater treatment technologies include advanced oxidation processes (AOPs), nanotechnology, membrane filtration technology, and automatic variable filtration (AVF) technology. There are various researches being performed in the field of nanotechnology for developing advanced treatments that can decompose toxic substances. The upcoming technologies for wastewater treatment and reuse include fabrication of nanomaterial membranes, using catalysts for decomposing noxious compounds, and using mixed oxides, bimetallic nanoparticles, carbon compounds, metals and zeolites. This book includes some of the vital pieces of works being conducted across the world, on various topics related to wastewater treatment and reuse technologies. The various studies that are constantly contributing towards advancements in this field have been examined in detail. The book will serve as a valuable source of reference to graduate and postgraduate students.