紫外/臭氧复合杀灭水中细菌性能研究

为开发一种高效灭菌方法,研究了UV/O3的复合灭菌性能,对紫外辐射、臭氧和羟基自由基等在体系中的各自作用进行探讨,同时考察pH值、温度等对灭菌效果的影响.结果表明,UV/O3较单独紫外或臭氧灭菌时效果有所提高,在初始臭氧质量浓度为5.02mg·L-1,液面紫外辐射强度为6.5mW·cm-2,灭菌时间1.5～9.0s时,UV/O3对细菌总数灭菌率达3.6～6.4,单独紫外时为1.8～4.7,单独臭氧时仅为1.6～3.0.羟基自由基的产生是复合灭菌效果增加的主要原因.随紫外辐射强度和臭氧投加量的增加,复合灭菌作用得到提高.pH值在5.5～8.5变化时,UV/O3灭菌效果随原水pH值的增加略有提高.温度由10℃上升到27℃时,灭菌效果稍有下降.由此可见,UV/O3是一种高效可行的水体灭菌技术。

Effect of UV radiation and ozone combined on water sterilization

In order to develop a high efficiency sterilization method,the inactivation efficiency of combined UV/ozone process was evaluated,and the effect of ultraviolet intensity,ozone concentration,hydroxyl radical,pH value,and temperature on inactivation of total bacteria was investigated.Results indicated that compared with individual unit processes of ozone or UV,the inactivation of total bacteria and coliform group by the combined ozone/UV process was enhanced under identical conditions.With an initial ozone concentration of 5.02 mg·L-1,a UV fluence rate of 6.5 mW·cm-2,and a sterilization time ranged from 1.5 to 9 s,the inactivation ratio of UV/O3 process reached 3.6-6.4,while using only UV and ozone alone reached 1.8-4.7 and 1.6-3.0 respectively.The presence and absence of hydroxyl radical experiment demonstrated that the formation of hydroxyl radical was the main reason for the enhancement of inactivation efficiency.With the ultraviolet intensity and ozone concentration increasing,the sterilization efficiency was improved.When the pH value ranged from 5.5 to 8.5,the sterilization efficiency increased with the pH value,while the temperature increased from 10 ℃ to 27 ℃,the efficiency of sterilization decreased a little.These suggest that UV/O3 process has potential for water sterilization.