菌株qy37的异养硝化/好氧反硝化机制比较及氨氮加速降解特性研究

Comparison of Heterotrophic Nitrification and Aerobic Denitrification System by Strain qy37 and Its Accelerating Removal Characteristic of NH_4^+-N

筛选出1株耐盐异养硝化-好氧反硝化菌qy37,通过形态观察、生理生化试验和16S rDNA序列分析,确定其为假单胞菌属(Pseudomonas).研究了异养硝化-好氧反硝化菌qy37的脱氮特性.在以NH4Cl为氮源的异养硝化系统内,该菌32 h内使NH 4+-N由138.52 mg/L降至7.88 mg/L,COD由2 408.39 mg/L降至1 177.49 mg/L,NH2 OH最大积累量为9.42 mg/L,NO 2--N最大积累量仅为0.02 mg/L,推测该菌将NH2OH直接转化为N2O和N2从系统中脱除.在以NaNO2为氮源的好氧反硝化系统内,该菌24 h内使NO 2--N由109.25 mg/L降至2.59 mg/L,NH2OH最大积累量为3.28 mg/L.好氧反硝化系统与异养硝化系统相比菌体生长量高,TN去除率低,COD消耗量低,NH2OH积累量低,并且检测到NO 3--N的积累.认为好氧反硝化在菌体生长和能量利用方面比异养硝化更有效率.在异养硝化-好氧反硝化混合系统内,16 h NH 4+-N去除速率比异养硝化系统提高了37.31%.混合系统的NH2 OH积累量低于异养硝化系统和好氧反硝化系统,但N2 O产出量高于二者.

The characterization in nitrogen removal of a heterotrophic nitrification-aerobic denitrification bacteria（qy37）was studied.A strain coded as qy37 which had simultaneous heterotrophic nitrifying and aerobic denitrifying ability was screened.In the light of its morphological and physiological characters as well as their sequence analysis of the 16S rDNA,strain qy37 was identified as Pseudomonas sp..In heterotrophic nitrifying system utilized ammonium chloride as nitrogen source,the concentration of NH 4＋-N reduced from 138.52 mg/L to 7.88 mg/L and COD reduced from 2 408.39 to 1 177.49 mg/L by strain qy37 in 32 hours,the maximum accumulation of NH2 OH and NO 2--N were 9.42 mg/L and 0.02 mg/L respectively,it was speculated that NH2 OH was transformed to N2 O and N2 directly by strain qy37.In aerobic denitrifying system utilized sodium nitrite as nitrogen source,the concentration of NO 2--N reduced from 109.25 mg/L to 2.59 mg/L by strain qy37 in 24 hours,and the maximum accumulation of NH2 OH was 3.28 mg/L.Compared with heterotrophic nitrifying system,aerobic denitrifying system had a higher bacterial growth whereas the lower removal rate of TN and COD,as well as the accumulation of NH2 OH.NO 3--N was also detected in aerobic denitrifying system.It is considered that the upgrowth of bacterium and utilization of energy in aerobic denitrifying system were more efficient than that in heterotrophic nitrifying system.In heterotrophic nitrification-aerobic denitrification system,the removal rate of NH 4＋-N improved 37.31% in 16 hours than that in heterotrophic nitrifying system,the accumulation of NH2 OH was less but N2 O was higher than that in both heterotrophic nitrifying system and aerobic denitrifying system.