The creation of three nanoparticles and their use in the photocatalytic degradation of organic contaminants found in dairy effluent is reported here using a sustainable and repeatable process. Physicochemical techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray, were used to characterize the materials. The photocatalytic degradation of methyl violet using three nanoparticles is investigated using a UV–Vis spectrophotometer. Solar radiation and nanoparticles were investigated to improve photocatalysis procedures. The study aimed to determine the effects of concentrated sunlight and combined catalysts on chemical oxygen demand (COD), biochemical oxygen demand (BOD), and bacterial inactivation. The concentrated sun approach achieved 90% and 95% COD and BOD removal efficiency. Comparing all the metal oxide nanoparticles, the combined nanoparticles ZnO/CdS/SnO2 demonstrate significantly better performance in the photocatalytic process. The main objective is to treat dairy wastewater for reuse for various social purposes.