This book includes the general information on the selected treatment techniques that used to solve a particular wastewater problem. Adsorption has proved that it is the best process of water treatment technologies, because of its significant advantages. Green synthesis of nanoparticles approach has been actively pursued in recent years as an alternative, efficient, inexpensive, and environmentally safe method for producing nanoparticles with specified properties. Molecular imprinting technology (MIT) today is also considered as a viable synthetic approach to design robust molecular recognition materials able to mimic natural recognition entities. On the other hand, advanced oxidation processes ( AOPs), in a broad sense, refers to a set of chemical treatment procedures designed to remove organic (and sometimes inorganic) materials in water and wastewater by oxidation. A new a class of crystalline porous materials possessing ordered structures, high surface area, adjustable functional groups and numerous active metal sites, metal-organic frameworks (MOFs) could be promising candidates in pollutant removal. In this book, a panoptic survey of techniques has been compiled.