Hydrodynamic cavitation as a promising route for wastewater treatment - A review

As one of the advanced oxidation processes, the cavitation-based process has become a promising technology for treating industrial effluents due to the advantages of cost-effectiveness in operation, higher energy efficiencies, and large-scale operation. In hydrodynamic cavitation (HC), cavities are generated as a result of local pressure drops caused by various constrictors or by mechanical rotation of the vortex diode and other rotating-type devices. The study on the influence of various geometric parameters of different kinds of HC reactors and the operation conditions is popular among researchers. In the present work, we systematically introduced the formation of HC and the mechanism of degradation of pollutants by HC. Further, for various cavitating devices, the influence of various geometrical and operating parameters affecting the cavitation conditions was discussed in detail. Overviews of earlier work based on the different types of HC reactors including venturi, orifice plate, rotating-type HC devices, and vortex diode were elaborated. Moreover, a detailed summary of HC-based hybrid technologies employed in recent work was presented to better show the synergetic index of different processes. Some recommendations for future work have been proposed.

Automated summary

The cavitation-based process is a promising technology for treating industrial effluents due to its cost-effectiveness, high energy efficiency, and large-scale operation capability. Researchers are exploring the influence of different geometric parameters and operating conditions on cavitation reactions in various HC reactors. The study introduced the formation of HC, the mechanism of pollutant degradation by HC, and the factors affecting cavitation conditions in different cavitating devices.