Screening And Characterization Of Aerobic Denitrifying Bacteria

Water resources shortage and serious water pollution in our country,the traditional biological denitrification technology due to the high cost of infrastructure,such as large energy loss causes all restrict the biological denitrification technology applied in industry,especially for refining wastewater with large amounts of toxic and harmful substances,is still the key difficulties in the field of water treatment,reform the traditional biological denitrification process,solve the denitrification refining waste water is very important.This paper was isolated from activated sludge refining wastewater denitrification advantages were screened,on the physiological and biochemical identification and gene sequence detection,analysis and evaluation of nitrifying and denitrifying denitrification performance,studies the environmental factors affect the performance of bacterial proliferation and denitrification,nitrification and denitrification of bacterial species functional genes were tested,and the determination of the activity of enzyme gene function,and finally in the best condition to filter good aerobic denitrifying bacteria is applied to actual refining waste water treatment,so as to provide theoretical basis for solving the problem of refinery wastewater treatment and technical support.The results showed that the aerobic denitrifying strain Y3 was gram-negative,and the bacterium was pseudomonas scheier.With ammonium chloride as the only nitrogen source,TN removal rate was 93.3%,NH₄⁺removal rate was 97%,and with potassium nitrate as the only nitrogen source,TN removal rate was 88.7%,NO₃^-removal rate was100%,and COD removal rate was 94.3%within 48 hours,indicating that the bacteria had strong nitrogen removal ability.The optimal environmental conditions are p H range 7-9,rotational speed is 160 r/min,C/N is 25,high-quality carbon source is sodium succinate,temperature is 30?.From the one-week denitrification effect diagram of the refractory carbon source,it can be seen that strain Y3 has low efficiency of using the refractory carbon source,and can add high-quality carbon source to improve the denitrification ability.Nitrification denitrification functional genes are successful amplification,and nitrogen metabolism path is:under the action of ammonia nitrogen in ammonia single oxygenase oxidation for hydroxylamine,further oxidized under the action of the hydroxylamine oxidase,nitrate nitrogen,nitrate nitrogen under the action of nitrate reductase,reduction of nitrate nitrogen,the last under the effect of nitrite reductase reduction for nitrogen gas;In the actual treatment of refining wastewater,the removal rate of NH₄⁺,NO₃^-,TN,COD and nitrous nitrogen was 92.5%,88.9%,73.7%and 56.4%within 24 hours,respectively.Therefore,the application of aerobic denitrifying bacteria in denitrification of refinery wastewater has a broad prospect.