Applications of electrical field and discharge in safe sterilization of drinking water
电场与放电杀菌技术应用于饮用水安全消毒的研究

An air-insulated coaxial-falling film reactor was applied in drinking water sterilization in this study. The sterilization efficiency test results indicated that under the operational condition of 10 kV input voltage, 12.5 kHz frequency and 50 s treatment time, the sterilization efficiency of corona discharge could achieve 3.85 and 3.77 orders of magnitude reduction for electric field sterilization. The higher sterilization efficiency for discharge sterilization was attributed to higher energy utilization efficiency compared with electric field sterilization. Furthermore, flow cytometer (FCM) and fluorescence microscope tests were utilized to reveal the sterilization mechanism. The results confirmed that both discharge and electric field sterilization can cause protein damage. However, in the case of electric field sterilization, the membrane damage was reversible, which resulted in the existence of sub-lethal cells. While in the case of discharge sterilization, the membrane damage was irreversible. The safety assessment of drinking water sterilization was also conducted by radical generation measurements. Our results showed that no radical was generated during electric field sterilization. Thus, based on all above mentioned results, electric field sterilization is a promising drinking water sterilization technology.