供水系统中蠕虫的强化氧化灭活机理及灭活效果

As one of the obvious problems of drinking water quality in current water supply system, the appearance of worms, which will result in aquatic organism and microorganism risks, can not only induce sensory discomfort, but also carry pathogens and opportunistic pathogens. Though inactivation by oxidants is the favorite control technology of worms’ risk, its inactivation efficiency is difficult to meet the required standard because of worms’ biochemical and physiological properties, and special requirements of water supply system to water quality and supply cost. Based the increase of worm inactivation efficiency by oxidants as cut-in point, the barrier effect of worm epidermis on oxidants, and the injury and damage effect of oxidants on worm’s antioxidant system are studied in this research. Meanwhile, the extinction and enhancement effect of UV on worm barrier effect and antioxidant system’s damage respectively, are also discussed. This research is mainly aimed at elucidating penetration process of oxidants in worm epidermis, revealing promoting mechanism of UV to oxidants’ penetration process, definiting the injury way and damage effect of oxidants on worm’s antioxidant system, uncovering the enhancement mechanism of UV to worm antioxidant system’s damage, establishing high performance control technology of worm risk by combining UV and oxidants inactivation, and getting optimal operation conditions of the combined technology. The research will provide a theoretical basis on and technical support to worms risk control in water supply system, and ensure aquatic organism and microorganism safety of drinking water quality.

作为当前供水系统的突出水质问题之一，蠕虫的出现不但引起感官不适，还常携带大量病原菌和机会致病菌，引发水生生物和微生物风险。氧化灭活是目前的主流蠕虫控制技术，但由于蠕虫自身生理生化特性和供水系统对水质与成本的特殊要求，其灭活效果往往难以达到要求。本项目以提高蠕虫氧化灭活效率为切入点，研究蠕虫表皮层对氧化剂的屏障效应和氧化剂对蠕虫抗氧化系统的破坏损伤效应，探讨紫外对屏障效应的削弱和对抗氧化系统破坏损伤的增强作用；阐明氧化剂在表皮层的透过过程，揭示紫外对氧化剂的促透作用机理；判明氧化剂对抗氧化系统的破坏途径和损伤效应，探明紫外对抗氧化系统破坏损伤的强化机理；建立紫外和氧化灭活联用的蠕虫风险高效控制技术方法，并获得优化运行条件。该研究可为供水系统蠕虫风险控制提供科学的理论指导和直接的技术支持，保障供水水质的水生生物和微生物安全性。

城市供水系统中蠕虫的出现会引发水质恐慌。由于蠕虫对消毒剂耐受性较强，很难被消毒工艺灭活。本研究以颤蚓为研究对象，通过分析氧化灭活效果、表皮超微组织结构和抗氧化系统变化，研究了氧化剂对蠕虫的灭活动力学过程，解析了蠕虫对氧化剂的应激行为，剖析了紫外照射对氧化灭活效果的强化机理。主要成果如下：1）探明了蠕虫对氧化剂胁迫的应激行为，主要包括表皮层的屏障效应、脂质层的阻碍，以及由SOD、CAT和GPX等组成的抗氧化系统的保护。2）阐明了氧化剂对蠕虫的灭活动力学过程和机理，次氯酸钠和二氧化氯对蠕虫的灭活动力学过程符合伪一级延迟Chick-Watson模型，灭活反应活化能分别为8754.31 J/mol和9959.84 J/mol；氧化剂对蠕虫的灭活作用机理，除与自身的强氧化性有关外，还与氧化剂对蠕虫的脂质过氧化作用和对O2-、H2O2等含氧自由基的诱导相关。3）揭示了紫外照射对氧化剂灭活蠕虫的强化作用机制，包括紫外照射对蠕虫的脂质过氧化作用和对抗氧化酶系统的破坏作用。紫外照射剂量为80 mJ/cm2时，蠕虫体内MDA浓度提高近3倍，同时SOD活性显著降低，CAT活性的显著增加。4）建立了紫外照射和氧化灭活联用的蠕虫风险高效控制技术方法，具体技术方案为“紫外照射+氧化”顺序灭活，优选的紫外照射剂量为40 mJ/cm2，次氯酸钠CT为60 mg min/L时，提高pH值和降低浊度、CODMn有助于灭活效果提升。以上研究为城市供水系统蠕虫风险控制提供了理论依据和技术支持，保证居民饮水安全。