| Water is the source of life. Drinking water safety directly relates to people’s life and health, and it is essential for social stability and economic development. Disinfection process is the most critical and final barrier to protect the microbiological safety of drinking water. Aiming to solve the problem of microbial contamination in drinking water, we carry out researches on drinking water disinfection by active oxygen radicals and application in this paper. We investigate the formation efficiency and impact factors of active oxygen radicals based on strong electric field discharge and hydrodynamic cavitation using a homemade experimental system. We carry out tests with synthetic microbial-contaminated water and source water in different seasons, and evaluate the inactivation efficiency, inactivation mechanism, changes of general water quality, and potential disinfection byproducts. Results show that:(1) Atmospheric electric field discharge combined hydrodynamic cavitation technology can generate active oxygen radicals efficiently. Discharge power, raw gas flow, reactive oxygen species flow, and water flow have effects on the generation efficiency. There are higher than 8 mg/L of active oxygen radicals and 33μmol/L of hydroxyl radicals formed in water, while the discharge power is 80 W and the reactive oxygen species flow is 1.0 L/min.(2) Active oxygen radicals generated by atmospheric electric field discharge combined hydrodynamic cavitation can kill bacteria efficiently in water,100% inactivation ratio for 104～106 cfu/mL of E.coil is obtained by 0.5～0.7 mg/L of active oxygen radicals in 3～10 seconds. Hydroxyl radicals play the most crucial role in the sterilization process.(3) Strong oxidation of active oxygen radicals can damage the barrier function of bacterial cell walls and membranes, resulting in leakages of intracellular materials. While entering the interior of cells, the active oxygen radicals will degradate intracellular proteins, destruct protective enzymes, and ultimately cause bacteria death.(4) Drinking water disinfection method of active oxygen radicals has good applicability on surface source water. Reservoir water can meet the microbial standards for drinking water after treated by 0.8～1.2 mg/L of active oxygen radicals in 1 min. Meanwhile, the turbidity and color degree of source water decrease significantly. The values of UV254 are declined 68%～76% by active oxygen radicals.In addition, there are no disinfection byproducts (such as formaldehyde, bromate, trihalomethanes and trihaloacetic acid) in treated water. |
