Hydrodynamic Cavitation: Principles, Applications, and Challenges in Wastewater Treatment

Refractory and recalcitrant contaminants are typically found in industrial wastewater and are challenging to eliminate using standard physical, chemical, and biological methods. Because HC may produce a locally intense system with high levels of temperature, pressure, and reactive radicals, it has been one of the most promising AOPs in recent decades. Complex contaminants in sewage may oxidize as a result of vapor bubbles collapsing in a liquid. This paper has covered the fundamentals of HC in great detail, including reactor components, cavitation mechanisms, and the chemical reaction pathways involved in HC. A comprehensive review has also been carried out relating to practical applications of HC in the treatment of wastewater of some industrial processes in terms of advancements achieved in reducing toxicity removal of color and reduction of chemical oxygen demands. Additionally, the synergistic effects of HC in the presence of oxidizing agents such as ozone and hydrogen peroxide, that shown a significant increase in treatment efficiencies, are discussed. Hydrodynamic cavitation is offered as a sustainable, energy-efficient, and very promising technique for advanced industrial wastewater treatment, despite current issues with reactor erosion, scale-up restrictions, and regulation of cavitation intensity.