<p>This review addresses innovative synthetic approaches for creating nanomaterials sourced from different waste materials such as bio wastes crop residues, food waste and industrial wastes including spent battery waste and polythene waste etc. The discussion will cover the pre-treatment techniques employed to transform waste into valuable nanomaterials, including metallic/carbon nanoparticles, carbon nanotubes, nanosheets, and nano-activated carbon through chemical and thermal activation methods. This article also elaborates the application of these waste-derived nanomaterials in enhancing water quality and safety, particularly in wastewater treatment. The advantages and disadvantages of utilizing nanomaterials in the water treatment process were also examined. Future prospects regarding the application of nanomaterials in water treatment were also addressed. A critical finding of this article is that the use of nanomaterial presents a sustainable solution for the removal of heavy metals and micro contaminants from wastewater at a rate that surpasses conventional methods, although they exhibit poor mechanical stability. Further research is necessary since little is understood about the causes of toxicity; comprehensive studies must be conducted to elucidate the relationship between the physicochemical properties of nanoparticles (NPs) and their toxic effects in wastewater.</p>