Yes, it is the best topic for you, without UV disinfection, effluent can retain a mass of hazardous pathogens that could infect the natural water, causing potentially serious environmental health issues. UV light deactivates pathogens so that they cannot survive in clean water, meaning they cannot replicate and infect future waterways. Greywater treatment by UVC/H(2) O(2) is the best technology to the removal of chemical oxygen demand (COD). It can be reduced COD 223-250 to 20-25 ppm. Most of the contaminants can be removed by oxidation since only 13-15 % COD is removed by settlement. The main advantage of using UV/H2O2 for water and wastewater systems resides in the fact that UV radiation can work simultaneously as a disinfectant, by physically inactivating microorganisms, and helping in the photolysis of peroxide, breaking it into the highly reactive hydroxyl radical species. It combines a deep theoretical basis with a chemical engineering approach for both theoretical and practical applications of the UV/H2O2 oxidation process. At the longer wavelengths, the gas phase absorptivities are significantly larger than the corresponding values in condensed phase.