The Screening And Identification Of Heterotrophic Nitrification Bacteria And The Study Of Denitrification

At present,the eutrophication has become a global environmental issues,and the governance of nitrogen pollution at home and abroad is growing importance. Because of the rapid and the security of the biological denitrification technology, it is favored.Heterotrophic nitrification as a new biological denitrification technology,in some respects,has some unique advantages compared with traditional biological denitrification technology,and it is becomeing a hot research.In this paper,against the features of heterotrophic denitrifying bacteria, I have isolated a highly efficient nitrification heterotrophic strain from paddy soil by using dilution method.From the characteristics of the strain in the preliminary study,I found that this strain could use different carbon and nitrogen for its growth,but the growth of the strain is not the same in different carbon and nitrogen sources.While the strain of life cycle is short,and grows fast;when the oxygen content up to 4 mg / L,it still could grow.In simulation experiment of nitrogen-containing wastewater,when the ammonia concentration is up to 105 mg / L,nitrite concentration is to 95 mg / L and nitrate concentration is 69 mg / L,at this time,the strains on the removal of ammonia is to 53.2%,the removal of nitrite to 73.5%and nitrate to 89.4%.And it is confirmed that the effect of nitrogen of the strain is the best,when the PH value is Partial alkaline medium,the temperature is 35℃,dissolved oxygen is 4.12 mg / L that is the speed of shaker is 200r/min and C/N is 15.This not only confirmed the heterotrophic nitrification of strain,but also provides a basis for the future of the experimental study.It is determined by a microscope that the bacteria B9 is a Bacillus and its shape are nemaline,dyeing is Gram-positive and with bacillus.The results of the physiological and biochemical tests of the strain are that the strain can not use lactose,could liquefy the gelatin,return nitrate to original state, hydrolisis starch and secretes the rhzomorph to suppress the pathogenic bacterium. The determination for this strain is Bacillus Licheniformis through a series of physiology and biochemistry experiment.Under laboratory simulation experiment premise,,the strain is vaccinated in the cultivation sewage,through 7 day-long raise,finally it ascertain that the Ammonia nitrogen elimination rate is to 54.02%and nitrite elimination rate is to 68.42%.Therefore,further confirmation is that this separation strain is a highly effective denitrogenation Bacterium.