After primary and secondary treatment processes, disinfection is necessary to eliminate pathogens present in the treated wastewater. Chlorine has been a traditional disinfectant in sewage treatment, but due to concerns about chlorine by-products and their environmental impact, alternative disinfectants like ozone and ultraviolet (UV) light have gained popularity. Ozone is a powerful oxidant that effectively kills bacteria and viruses, while UV light offers a chemical-free disinfection method. The choice of disinfectant depends on various factors, including cost, effectiveness, and environmental considerations.