Isolation And Denitrification Characteristics Of Aerobic Denitrifier

This study aims at the isolation of an aerobic denitrifier with high nitrogen removal ability from caprolactam sewage and its denitrifying characteristics.Five aerobic denitrifier with good denitrifying performance were isolated from the sample by BTB medium preliminary screening and nitrate degradation analysis.AD-9 was selected after the further performance detecting.We used morphological and physiological characteristics as well as its 16 S rDNA sequences to identify this strain.Effects of culture conditions,such as carbon sources,C/N ratio,nitrogen source concentration,temperature,initial pH and DO were evaluated regarding denitrifying capacity under aerobic condition.The highly effective strain AD-9 was identified as Pseudomonas citronellolis.Studies of degradation characteristics showed that the most efficient nitrate removal rate for AD-9 was occurred at C/N = 12 when sodium succinate or sodium acetate was supplemented as the carbon source,and the nitrogen source concentration ranged from 100 to 1000mg/L.The optimum temperature for B-5 was 30-35?,the optimum pH ranged 6 to 7,and the best shaking speed is 150r/min.Most aerobic denitrifying bacteria own the ability of heterotrophic nitrification.The study found that five screened aerobic denitrifying bacteria also have that ability.Experiments showed that the optimum pH for heterotrophic nitrification capacity of AD-9 was 8 and the optimum temperature was 25-30?.Mix the other four strains with AD-9 respectively.The study found that there was a slight growth on TN removal of all these synthetic bacteria compared with AD-9 alone,and the denitrification performance of compound bacteria of AD-1 and AD-9 was the best.Treat the petrochemical sewage with the multiple microorganisms and the result showed that the total nitrogen removal rate of CAST and acid hydrolysis pool effluent reached about 85% and 80% respectively.