Study On The Removal Of Copper,zinc And Chromium From Water By A Strain Separated Serratia Bizio And Microcolus Vaginatus

The electroplating industry has become an important part of industrial production,the each process of which involve the discharge of heavy metals,especially a large number of heavy metals in waste water.If they are not disposed in a qualified way,the environment will be permanently polluted.Recent years,the technology of using microorganisms and microalgae to remove heavy metals from water bodies has become a hot research topic,for its advantages of high efficiency and environmental protection.This study explores the process that the microorganisms and algae successively remove the heavy metals from electroplating wastewater,the conclusions of which are shown as follows:?1?A sulfate-reducing bacterium that is resistant to copper,zinc and chromium was screened from electroplating wastewater and named DW7-3.The 16S rDNA sequence of DW7-3 was compared and analyzed,and combined with the results of physiological and biochemical characteristics experiment.It was determined that the strain Dw7-3 belonged to the genus Mycobacterium?Serratia Bizio?.The Colony morphology formed by Dw7-3 on solid foundation medium was opaquely milky yellow thallus with moist surface and rough edge.The bacterial single bacterium was rod-shaped under the electron microscope.All these indicated that DW7-3 had the greatest growth activity at 30?,and the pH value of its optimum growth was about 7.7.?2?The removal effects of DW7-3 on heavy metals(Cu²⁺,Zn²⁺and Cr⁶⁺)showed that the removal effect of dw7-3 on Cu²⁺,Zn²⁺and Cr⁶⁺was obvious,and the standard of discharge can be achieved in 24h.Besides,the alkaline environment was more favorable to the removal of Cr⁶⁺,while the neutral environment was more favorable to the removal of Cu²⁺Zn²⁺,and the fastest removal rate was under the temperature of 30?.?3?Microcolus vaginatus as the experimental material,its optimum growth temperature and the removal effect of it on heavy metals(Cu²⁺,Zn²⁺and Cr⁶⁺)in electroplating wastewater under different temperatures were studied.The results showed that the optimum growth temperature of Microcolus vaginatu was 30?,and it had certain removal effect on Cu²⁺,Zn²⁺and Cr⁶⁺,and the best removal efficiency was achieved under the temperature of 30?.?4?DW7-3 and Microcolus vaginatus could produce flocculation phenomenon.And when the mixing ratio is 1:1,the flocculation effect is the most.It was indicated that microalgae could be used as a flocculation to separate the DW7-3 from the solution.?5?By small-scale actual production experiments on electroplating wastewater,it was showed that DW7-3 and the microalgae reduced the concentration of Cu²⁺,Zn²⁺and Cr⁶⁺.The treated the electroplating wastewater was released under the discharge standard.And the number of bacteria in the supernatant was significantly reduced after filtration.