Research On The Isolation And Aerobic Denitrification Characteristics Of Aerobic Denitrifer

Now, ammonia nitrogen is the primary indicator for the quality of surface waterand has been incorporated into the binding index of nations major water pollutantemissions. In water nitrogen pollution will cause water eutrophication and beharmful to human health. The ways of degradation of ammonia havephysical-chemical methods and biological methods. Owe to these advantages: beeconomical, efficient, no secondary pollution, handling large etc., the biologicalmethod are widely used.The theory of traditional biological denitrification is aerobic nitrifying bacteriaoxidize ammonia nitrogen to nitrate nitrogen, then nitrate nitrogen is reduced tonitrogen by anaerobic denitrifying bacteria. The traditional technology of biologicalnitrogen removal are separated the aerobic and anaerobic zones, it played a certainrole on wastewater denitrification, but it has some disadvantages, for example: largeenergy consumption, weaked impact resistance ability etc.. In recent years,researcher found that aerobic denitrification phenomenon and isolated aerobicdenitrifying bacteria. These offer a new way of thinking for biological nitrogenremoval, and promote simultaneous nitrification and denitrification process appear.In this paper,29bacteria with aerobic denitrification ability were isolated fromactivated sludge of aeration tank in ShengYang North Sewage treatment plant. Thestudy of biodegradation capability showed that N6was the effective aerobicdenitrifying bacteria. The colonial morphology of strain N6is round, surface smooth,the color is milky white. Gram stain of N6is negative, no spore, bacteria size is(0.4-0.5)×(2.4-3.0)μm. According to physiological and biochemical characteristicsand16SrDNA, the bacterium N6is identified as Pseudomonas sp..The study on growth and aerobic denitrification capacity of N6shows that theoptimal temperature, pH, C/N and the inoculum for strain N6are15℃,7,15:1and10%. The type of carbon source have a great impact on the denitrification,denitrification best carbon source for N6is sodium succinate. When the nitrate concentration is500mg/L, the degradation rate is90%and no accumulation ofnitrite in48h. The study on ammonia degradation shows that stain N6can reducedammoniato gaseous products independently. The growth and aerobic denitrificationcharacteristics of N6provides theory and technical support for its application in areal environment.