Research On Biological Characteristics And The Killing Effect Of Emerging Pathogenic Bacteria In Municipal Sewage

The pathogenic microorganism in the urban water body, which is a latent risk of biological pollution and harmful to public health, has aroused the widespread attention especially monitoring and safety assessment in the urban water body. In this thesis, the species of the pathogenic microorganism isolated in the water body was investigated by amplicating bacterium's 16S rDNA gene, the massive pathogenic microorganism physiological and biochemical characteristics. Then the origin of the dominant microflora in the water body was explored and the effect had been appraised in removing the pathogenic microorganisms by the existing sewage treatment process. All the research provided the essential data for control the pathogenic microorganism pollution in the urban water body and also indicated the direction for the source control the pathogenic microorganism. The research mainly obtained the following conclusion:(1)The pathogenic microorganisms were identifed by extracting the bacterial DNA and amplifying 16S rDNA gene fragment using PCR. Combining the modern molecular biology technology methods and traditional physiology biochemistry experiment we found that, there were many kinds of pathogenic microorganisms in the Zhenjiang urban water body and 6 speices of bacterium were identified. They were respectively JD16, Aeromonas hydrophila, JD17, Acinetobacter rhizosphaerae, JD18, Myroides odoratus, JD25, Vagococcus fluvialis, JD27, Brevundimonas diminuta, JD32, Shewanella putrefaciens.(2) Then the growth curves and growth factors (temperature, oxygen and pH) of Aeromonas hydrophila and Myroides odoratus were determined. The results showed that Aeromonas hydrophila and Myroides odoratus were in a better growth around 30℃, and were more suitable growing in sewage of pH values of about 7. Aeromonas hydrophila and Myroides odoratus both had strong resistance toβ-lactam antibiotics such as Ampicillin, Cephalosporins and CCDA.(3) By calculating the survival rate we researched the survival laws of Aeromonas hydrophila and Myroides odoratus in municipal wastewater, urban sewage and river water, departly. The results showed that in different sewages, Aeromonas hydrophila and Myroides odoratus were more suitable at a lower temperature and both growed slowly in first few days and higher temperature was unfavorable for both. The Aeromonas hydrophila and Myroides odoratus strains respectively suvived well in the pH value of 5-8.5,5-11.5 in urban sewage relatively.(4) For Aeromonas hydrophila and Myroides odoratus as the target pollutants, the killing effects of ultraviolet radiation and ozone were studied, and the killing effect dynamic models were established. To killed Aeromonas hydrophila in culture medium and in regenerate water, the best exposure time of UV were 16min (2.3081g) and 10min (3.0191g), While to kill Myroides odoratus were 12min (3.941g), 10min (3.0991g), respectively. The optimal concentrations of ozone in water to kill Aeromonas hydrophila and Myroides odoratus were 18mg/mL (3.1191g) and 16.67 mg/mL (4.2831g), respectively. UV and ozone water killed the two new pathogens laws were both accored to the Collins-Selleck model.