Nanotechnology deals with developing and using nano-sized materials in different applications. The nano-sized materials used in items ranging from surfacing to devices, are at least one dimension of the size 1-100 nanometers (1 nanometers = 10−9 meter). This book provides details of the experiments conducted to synthesize such nanoparticles. The ideas to synthesize such nanoparticles stem from the fact that CaO (ordinary dry lime) is an ubiquitous substance that finds applications from water treatment to pesticide. Ca(OH)2, CaO and CaS naoparticles were successfully synthesized and applied in wastewater remediation. The results point to the scopes of utilizing such nanomaterials not only wastewater treatment, as reported in the work, but also in using them for various other industrial applications.