Disinfection in wastewater treatment: From conventional to emerging technologies

Wastewater disinfection constitutes the final barrier in wastewater treatment plants (WWTPs), thereby protecting ecosystems and human health. Conventional methods such as chlorination, ultraviolet (UV) radiation, and ozonation are well established, yet their performance is increasingly challenged by complex wastewater matrices, the presence of antibiotic-resistant bacteria and genes, and the formation of disinfection byproducts (DBPs). This review provides a critical synthesis of both conventional and emerging wastewater disinfection technologies, discussing their mechanisms of action, operational parameters, advantages, and limitations. Particular attention is given to advanced oxidation processes (AOPs) and hybrid systems, which offer the combined capacity for microbial inactivation and micropollutant removal. In parallel, we examine the growing role of real-time monitoring and artificial intelligence (AI) tools in predicting disinfection performance and optimizing chemical usage. Finally, current challenges and future prospects are discussed, highlighting the need to reconcile microbial safety, byproduct control, energy efficiency, and economic feasibility. The convergence of advanced treatment technologies with intelligent monitoring is expected to play a central role in ensuring safe and sustainable wastewater reuse under increasingly demanding regulatory frameworks.