Advanced Oxidation Processes and Their Applications

As a result of rising industrialization, wastewater production has increased dramatically,

necessitating effective treatment to safeguard ground and surface water

pollution (Khan et al., 2015). On the other hand, the heightened demand for water

reclamation and reuse requires innovative treatment techniques. Besides, the stringent

discharge standards further enhance the requirement for advanced treatment

options. The ineffective treatment creates many problems for the environment and

pollutes the water bodies, which is problematic for aquatic life and public health

(Mahtab et al., 2021). In recent years, trace organic compounds (TOrCs) have been

reported in the aquatic environment, including pharmaceuticals, consumer items,

and industrial chemicals (Khan et al., 2021). Aside from urban and agricultural

run-offs, wastewater treatment plant effluents are thought to be the largest source of

TOrC emissions (Gros et al., 2010; Luo et al., 2014). Because conventional physical

and biological wastewater treatment can only partially remove TOrCs, they remain

in wastewater treatment plant effluents released into surface waters (Luo et al., 2014).

As a result, environmentalists and researchers are concerned about their suitable

treatment. Advanced oxidation processes (AOPs) are considered highly effective and

viable choices for the degradation and removal of a wide range of contaminants and

TOrCs in these situations (Comninellis et al., 2008; Klavarioti et al., 2009; Yang

et al., 2014; Stefan, 2018; Hussain et al., 2020; Hussain et al., 2021).

AOPs form powerful oxidants in situ to oxidize organic compounds (Huang

et al., 1993; Hussain et al., 2020). These include processes that use OHradicals (●OH),

which account for most AOPs, and those that use other oxidizing species, such as

sulfate or chlorine radicals. Figure 5.1 depicts various oxidizing agents. Hydroxyl

radical-based treatments have multiple advantages, as widely documented in earlier

research. The hydroxyl radicals (●OH) are the principal reactive species in AOPs, and

Figure 5.2 depicts several favorable characteristics of the hydroxyl radicals (●OH).

A comprehensive analysis of AOPs regarding running costs, sustainability, and

general viability make selecting the most appropriate treatment techniques among

AOPs challenging. Several AOPs are well-established and in full-scale operation in

drinking water treatment and water reuse facilities, notably those involving ozonation

and UV irradiation. Various researchers are constantly presenting innovative

investigations of a range of evolving AOPs for water treatment (for example, electrochemical

AOPs, plasma, electron beam, ultrasound, or microwave-bas

Anwar Khursheed