pH值与曝气对硝化细菌硝化作用的影响

EFFECT OF PH AND AERATION ON NITRIFICATION OF NITROBACTERIA

目的探讨硝化细菌最佳工作条件 ,为应用和生产提供依据。方法通过人工调节液体培养基的pH值和充气 ,检测氨氮和亚硝酸盐氮转化率。结果分离的亚硝酸细菌在转化氨氮为亚硝酸盐氮的过程中产生大量强酸 ,可使pH值下降到 5 .6或更低 ,必须不断加入碱性物质给予中和。实验表明 ,培养过程中不加碱组氨氮转化率为 2 0 %左右 ,加碱组氨氮转化率则可达到99%左右。而硝酸细菌则产酸不明显 ,pH维持在 7.8～ 8.1。培养基连续充气可使氨氮在亚硝酸细菌的作用下去除率增加 89%左右 ,亚硝酸盐氮在硝酸细菌作用下去除率增加 85 %左右。结论硝酸细菌与亚硝酸细菌均为好氧菌 ,不断曝气给予充足的溶解氧 ,pH值维持在 7.5～ 9.0 ,才能更好地发挥其硝化作用。

Objective To study the best conditions of nitrification for nitrobacteria so as to provide the basis for nitrobacteria production and application. Methods Ammonia nitrogen(NH 3-N) and nitrite nitrogen(NO 2-N) transformation rates were measured by ajusting the pH and giving aeration to the culture medium. Results Ammonia-oxidizing bacteria produced much acid as it converted NH 3-N to NO 2-N,which could make pH lower than 5.6. Ammonia transformation rate was about 20% without alkali addition,whereas the rate was about 99% with alkali addition.Nitrite-oxidizing bacteria did not produce acid evidently,and the range of pH was 7.8～8.1. The elimination rates of NH 3 N by ammonia-oxidizing bacteria and NO 2-N by nitrite oxidixing bacteria were increased by about 89% and 85% respectively after continuous aeration to the culture.Conclusion Ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were aerobic bacteria. Nitrification of nitrobacteria would be more efficient when aeration was continuously given to supply soluble oxygen and the range of pH was kept at 7.5～9.0.