Which of the following is an advanced oxidation process (AOP) used in wastewater treatment?

Ozonation is recognized as an advanced oxidation process (AOP) used in wastewater treatment due to its ability to produce hydroxyl radicals, which are highly reactive species that can efficiently break down a wide range of organic contaminants present in wastewater. This process involves the injection of ozone gas into wastewater, leading to the oxidation of pollutants. Ozonation enhances the removal of refractory compounds that are often resistant to conventional biological treatment methods.

Advanced oxidation processes are characterized by their use of strong oxidants and their ability to generate hydroxyl radicals, which can effectively degrade complex organic molecules into simpler, less harmful substances. Ozonation meets these criteria, making it a suitable choice for improving effluent quality, particularly for wastewater containing persistent pollutants.

In contrast, the other options listed do not fit the criteria of AOPs. Filtration primarily focuses on the physical separation of suspended solids and does not involve oxidation. Chlorination, while effective for disinfection, does not create hydroxyl radicals and is primarily a chemical disinfection process. Activated sludge treatment is a biological method that relies on microorganisms to break down organic matter, rather than on advanced oxidative processes. Thus, ozonation stands out as the correct answer as it directly aligns with the definition and function of advanced oxidation processes