Drinking water disinfection based on strong electric field discharge and hydrodynamic cavitation

Reactive oxygen species (ROS, e.g., ·OH, ·O₂^-, ¹O₂, H₂O₂, O₃) produced in advanced oxidation technologies (AOT) are well accepted to be one of the most lethal factors that are responsible for bacteria inactivation during the drinking water treatment. However, the low production of ROS by existing AOT technologies (such as photocatalysis, ozonation) limits their widely applications in water treatment. In this study, an efficient method for reactive species producing and waterborne pathogens eliminating was developed, which consist of strong electric field discharge and hydrodynamic cavitation. The critical factor of reactive oxygen species for bacteria inactivation was investigated. Escherichia Coli as typical bacteria was used to evaluate the disinfecting efficiency. A serials of experiments were carried out to verify the effect of hydrodynamic cavitation on the cultivability of Escherichia Coli bacterial cells. The morphology and microstructure of Escherichia Coli during the treatments were also examined to better understand the inactivation mechanism of reactive species generated by the developed system. As a result, through strong electric field discharge and hydrodynamic cavitation, total oxidants (TO) producing in the water could reach a concentration higher than 10 ppm. 106 cfu/mL of Escherichia Coli could be completely eliminated in 5 s at a low TO concentration of 0.3 ppm. Hydroxyl radicals (·OH) produced with the method were supposed to be the critical factor for bacteria inactivation during the treatment. Owning the high production of ROS, the developed method as a clean water treatment technology can offer additional advantages over a wide range of applications.