Nano-biotechnology is widely considered to be the most advanced technology of modern era and is viewed as a significant benefit in the academic, scientific, and industrial sectors. The authors aimed to overcome the problems related to traditional cosmetic products and water contamination by employing emerging nano-biotechnology. This book focused on nanotechnology in cosmeceuticals; wastewater treatment using photocatalysis and ozonation;nanoporous membranes in water purification; removal of recalcitrant organic compounds using advanced oxidation processes; biosynthesis of metal oxides nanoparticles; challenges and future perspectives of nanomaterials; green approach to treat and recycle effluents of dyeing industries; advanced green technologies for wastewater decontamination.