| 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. ITlag, first order reaction rate constant, ITtail 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.
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