【作者】 张胜华；

【导师】 吴春笃；

【作者基本信息】 江苏大学 ， 环境工程， 2009， 博士

【摘要】 我国水资源稀缺，开发中水、利用中水迫在眉睫。城市中水由于其污染程度轻，水量稳定，故回用作生活杂用水最具发展前途。功率超声通过其机械作用、空化作用、热作用改变物质的物理、化学或生物特性。功率超声应用于回用中水消毒时，能够改变水中颗粒污染物的粒径组成、对细胞膜造成物理破坏、其空化现象产生的羟基自由基能够破坏微生物的细胞结构，但存在难以找到合适的超声源、单独作用时消毒不彻底、消毒物品的量不能太大等问题。紫外线消毒具有广谱杀菌、无二次污染等特点，但也存在着如微生物由于对紫外线的抗性而要求较高的辐照剂量、消毒效果依赖于进水水质、灭菌后存在光复活现象等缺点。功率超声与紫外协同作用对回用中水进行消毒，能够降低紫外辐射剂量，提高紫外消毒效果，有效抑制微生物的光复活现象。本研究以大肠杆菌、枯草芽孢杆菌、中水中大肠杆菌、中水中细菌总数为研究对象，考察超声、紫外、超声协同紫外的灭菌消毒效能；研究复合纳米光催化剂CoPcS／TiO₂对鲁米诺声致发光的增敏作用，并对声致空化的灭菌机制进行研究；通过生物学手段，对各种处理方式的灭菌机制进行研究。研究内容主要包括：（1）回用中水超声灭菌效能及机制研究实时荧光定量PCR技术与PMA结合，PMA可以通过破损的细胞膜进入死菌内部，与DNA交联，并发出红色荧光；通过平板计数法测定的细菌存活量与通过实时荧光定量PCR结合PMA测定的存活量之间具有良好的线性相关性，荧光定量PCR结合PMA技术可以替代平板计数法对超声的灭菌效果进行客观准确的评价。固定低频超声灭菌时，超声的功率密度越大，灭活速率越大，相同的作用时间内，超声的功率密度越大，灭活率越大；各目标处理物的最大相对功效值对应的工况的功率密度均为7．18W．cm^-2。变频超声灭菌时，超声的频率越大，灭活速率越小；大肠杆菌和枯草芽孢杆菌达到最大相对功效都是在20kHz超声作用6min，中水中大肠杆菌和细菌总数达到最大功效是在20kHz超声作用7min。高功率密度的超声处理对于大肠杆菌的细胞结构破坏比低功率密度的超声严重，低频率的超声处理对于枯草芽孢杆菌的细胞结构破坏比高频率的超声严重；在各种功率及各种频率的超声作用下，大肠杆菌的DNA都不能被破坏；固定频率（变频）超声作用时，超声的功率密度（频率）越大（小），反映大肠杆菌TFC脱氢酶活性的吸光度的减小速率越大。纳米CoPcS／TiO₂对鲁米诺声致发光具有增敏作用；在相同的作用时间内，超声作用的功率越大，超声空化场的蓝光范围越大、亮度越大；在相同的功率密度下，高频超声的发光强度大于低频超声，比低频超声作用产生更多的自由基，超声作用时产生的物理作用，即对细菌细胞膜、细胞壁的剪切作用，强于由于自由基氧化产生的灭活作用。（2）回用中水紫外消毒效能及生物学机制研究中水中的大肠杆菌对于UV的抗性大于大肠杆菌菌液，其灭活速率K值分别为0．0726min^-1、0．1min^-1。UV辐照枯草芽孢杆菌的IT_lag、一级反应K值、IT_tail分别为24mJ·cm^-2、0．03min^-1、>84mJ·cm^-2；中水中细菌总数的IT_tail、一级反应K值、IT_tail分别为12mJ·cm^-2、0．05min^-1、>96mJ·cm^-2，枯草芽孢杆菌对于紫外的较强的抗性是自身结构导致的。Chick一级反应动力学模型能够体现出大肠杆菌的灭活特性，Collins-Selleck和Hom模型能够体现出枯草芽孢杆菌和中水中细菌总数的灭活特征。各紫外辐照剂量下的大肠杆菌均发生了光复活现象，在相同的紫外辐照剂量下，中水中的大肠杆菌的光复活率小于菌液中大肠杆菌的光复活率；枯草芽孢杆菌光复活现象不明显；中水中的细菌总数的光复活率低于中水中的大肠杆菌的光复活率。一定时间内的紫外线辐照不能改变细菌的细胞形态结构；各紫外辐照剂量及不同的光复活时间下，T₄核酸内切酶V酶切后产生的ESS的含量能够反映出大肠杆菌灭活率，二聚体的形成是紫外线对DNA分子的主要损伤方式：反映大肠杆菌ITC脱氢酶的吸光度值随着紫外辐照剂量的增加而减小，在紫外的作用下，体系的TTC脱氢酶的活性被减弱。（3）回用中水超声协同紫外消毒效能及生物学机制研究超声协同处理后，紫外灭菌的反应速率增大，枯草芽孢杆菌和中水中细菌总数的IT_lag减小、一级反应K值增大、IT_tail值增大，使灭活反应更早脱离停滞区，反应速率增大，更晚到达拖尾区。欲达到相同的处理目标，超声协同作用时所需紫外剂量的减小幅度在18％-76％之间，在相同的紫外剂量下，超声与紫外协同作用强化百分比为18％-97％之间；对于四种目标处理物，超声与紫外协同作用的灭活速率及强化百分比大小顺序均为US／UV>US-UV>UV-US，枯草芽孢杆菌在各个协同方式下的强化百分比最大。超声与紫外协同处理后，大肠杆菌依然发生了光复活现象；超声与紫外协同作用比单独紫外作用的光复活率低，且US／UV的光复活速率最低。超声与紫外同时作用的协同方式对细胞形态结构的破坏最严重、产生的二聚体最多、反映大肠杆菌TTC脱氢酶的吸光度值的减小速率最大。从生物学角度说明超声的协同作用大大强化了紫外消毒效果。更多还原

【Abstract】 Water resource in our country is scarce, and the reuse of urban wastewater is necessary. It is urgent to develop and utilize recycled water. As slightly pollution and stable water quantity, it is attractive for urban greywater to reuse as domestic miscellaneous water.Power ultrasonic can alter the physical, chemical and biological feature of matters by mechenical, cavitation and themal effect. Power ultrasonic can change the grain size distribution of partical pollution, destroy bacterial membrane and structure by hydroxyl radical. UV dose can be reduced, disinfection result can be improved and photoreactivation can be controlled by UV disinfection with ultrasonic pre-treatment. UV disinfection is a kind of physical disinfection technology, which can disinfect extensively and without secondary pollution. UV disinfection still has some disadvantage, such as needing high UV dose because of the resistance of bacteria to UV, result of disinfection depending on influent quality and photoreactivation occouring after disinfection.Propidium monoazide （PMA） was combined with real time fluorescence quantity PCR to realize accurate and rapid detection to the disinfection effect by ultrasonic. E.Coli, B. subtilis, E.Coli in reclaimed water and total bacteria in reclaimed water were taken as research object, and effect of disinfection and photoreactivation controlling under UV, US and US combined with UV were studied, and the optimal operating condition were determined. The mechnisim of photoreactivation of E.Coli controlled by US effectively was investigated by microbiological method. Sensitizing effect of composite nano-CoPcS/TiO₂ to luminol sonoluminescene was researched. Inactivation mechanism of cavitation induced by sound was investigated by the phenomenon of luminol sonoluminescene. By means of molecular biology, the mechanism of UV disinfection and enhanced by US, photoreactivation were studied. The main conclusions included the following items:（1） Research on efficiency and mechanism of reclaimed water disinfection under USPropidium monoazide （PMA） was combined with real time fluorescence quantity PCR to detecte the inactivation rate of E.Coli and B. subtilis by ultrasonic. Through microscopic examination, which could be observed that PMA combined with DNA through forewom membrane, and red fluorescene sent out under UV. There was liner relationship between survival amounts detected by PCR combined with PMA and plate counting method, and the correlation coefficient were 0.8918 and 0.8899, which could confirm that it was objective and exact to detect inactivation effect under US by PCR combined with PMA.The power intensity was important to inactivation result under US with fixed low frequency, and the optimal operating condition all were: volume 50mL, power intensity 21.3Wcm^-2, action time 60S. Under variable frequency, influence order all were frequency>action time>powerintensity, and these three factors all had not statistical significance. The bigger the power intensity was, the bigger the inactivation speed was. Under the same action time, the bigger the power intensity was, the bigger the inactivation rate was. The bigger the frequency was, the less the inactivation speed was.The power intensity corresponding to the biggest relative efficiency value under low frequency US was 7.18W·cm^-2. Under variable frequency, the biggest relative efficiency value of E.Coli and B. subtilis occurred under US of 20kHz 6min, and that of E.Coli in reclaimed water and total bacteria occurred under US of 20kHz 7min. US of higher power intensity could damage bacterial structure of E.Coli more seriousely than that of lower intensity. US of lower frequency could damage bacterial structure of B. subtilis more seriousely than that of higher frequency; DNA of E.Coli could not be damaged under every power and frequency. Bigger was the power intensity （frequency）, bigger was the reducing rate of absorbance which reflected the activity of TTC-dehydrogenase.Nano-CoPcS/TiO₂ had obvious sensitizing effect to luminol sonoluminescene. During the same action time, bigger the power intensity was, the blue light of cavitation was more extensive and brighter. Under the same power intensity, luminescence intensity of high frequency US was bigger than that of low frequency, namely that the radicals produced by high frequency US was much than that of low frequency. The strengthening effect of US on UV disinfection mainly resulted from shearing destructive effect.（2） Research on efficiency and biological mechanism of reclaimed water disinfection under UVE.Coli in reclaimed water had stronger resistance to UV than E.Coli, and the inactivation rate were 0.0726 and 0.1 separately. IT_lag, first order reaction rate constant, IT_tail of B. subtilis were 24mJ·cm^-2, 0.03 and >84 mJ·cm^-2, of which for total bacteria in reclaimed water were 12mJ·cm^-2, 0.05 and >96mJ·cm^-2. The higher resistance of B. subtilis resulted from the bacterial structure. The first order reaction dynamic model of Chick Model could embody the inactivation feature of E.Coli, and the Collins-Selleck model and Horn model could embody the inactivation feature of B. subtilis and total bacteria in reclaimed water.Photoreactivation of E.Coli occurred under different UV dose. The photoreactivation rate of E.Coli in reclaimed water was less than that of E.Coli. The photoreactivation of B. subtilis was not obvious. The photoreactivation rate of total bacteria in reclaimed water was less than that of E.Coli in reclaimed water. UV radiation coule not change the bacterial structure. The content of ESS produced by T₄-EndoV digestion could embody inactivation rate of E.Coli under every operating condition, which demonstrated that it was reasonable to investigate the mechanism of UV disinfection by means of specific recognition of T₄-EndoV to CPDs. Bigger was the US dose, bigger was the reducing rate of absorbance which reflected the activity of TTC-dehydrogenase.（3） Research on efficiency and biological mechanism of of reclaimed water disinfection by US combined with USThe inactivation rates sequences under US combined with UV were all US/UV>US-UV>UV-US>UV. UV dose combined with US decreased 18%～76%. Under the same UV dose, the enhancement percentages were 18%～97%, that of B. subtilis was biggest. The synergistic effect of US and UV decreased the resistance of bacteria to UV.Photoreactivation of E.Coli still occurred after US combined with UV, and the photoreactivation rate decreased. The enzyme dimmers of photoreactivation after US combined with UV were more than UV, which demonstrated that US combined with UV controlled photolysis of enzyme dimmers. Under US/UV, the reducing rate of absorbance which reflected the activity of TTC-dehydrogenase was biggest.更多还原