Holistic insight mechanism of ozone-based oxidation process for wastewater treatment

Abstract

The world is facing water crises because freshwater scarcity has become a global issue due to rapid population growth, resulting in the need for more industries, agriculture, and domestic sectors. Therefore, it is challenging for scientists and environmental engineers to treat wastewater with cost-effective treatment techniques. As compared to conventional processes (physical, chemical, and biological), advanced oxidation processes (AOP) play an essential role in the removal of wastewater contaminants, with the help of a powerful hydroxyl (OH•) through oxidation reactions. This review study investigates the critical role of O₃-based Advanced Oxidation Processes (AOPs) in tackling the complex difficulties of wastewater treatment. Effective treatment methods are critical, with wastewater originating from various sources, including industrial activity, pharmaceutical manufacturing, agriculture, and a wide range of toxins. O₃-based AOPs appear to be powerful therapies capable of degrading a wide range of pollutants, including stubborn organics, medicines, and pesticides, reducing environmental and human health risks. This review sheds light on their efficacy in wastewater treatment by explaining the underlying reaction mechanisms and applications of several O₃-based AOP processes, such as O₃, O₃/UV, and O₃/H₂O₂. Ozone, a powerful oxidizing agent, stimulates the breakdown of complex chemical molecules by oxidation processes, which are aided further by synergistic combinations with ultraviolet (UV) radiation or hydrogen peroxide (H₂O₂). Notably, while ozonation alone may not always produce the best outcomes, it acts as an essential pretreatment step prior to traditional treatments, increasing total treatment efficiency. Furthermore, O₃-based AOPs' transformational capacity to convert organic chemicals into simpler, more stable inorganic forms with little sludge creation emphasizes its sustainability and environmental benefits. This study sheds light on the processes, uses, and benefits of O₃-based AOPs, presenting practical solutions for sustainable water management and environmental protection. It is a valuable resource for academics, engineers, and politicians looking for new ways to combat wastewater contamination and protect water resources.

Keywords: Advanced oxidation process (AOPs); Freshwater scarcity; Sustainable water management; Wastewater treatment; Water crises.