pH和硝化细菌浓度对氨氮氧化速率的影响

为实现氨氮氧化速率的提高，以污水处理厂A2/O工艺回流污泥为菌源，利用细菌发酵罐，通过间歇运行方式实现了硝化细菌菌群的筛选和富集。实验中通过调节系统pH值考察不同游离氨（FA）水平对氨氮氧化速率、亚硝酸盐积累和硝酸盐生成的影响，以及通过沉淀排水保留污泥，反应有效容积缩小，等同于污泥浓度提高的方式考察了硝化细菌浓度变化对氨氮氧化速率的影响。结果表明在一定氨氮底物浓度条件下适合的pH值是实现氨氮高速率氧化的重要条件，同时硝化细菌浓度是高氨氮氧化速率实现的物质基础。通过FISH检测，证明了所得培养物中，氨氧化和亚硝酸盐氧化细菌菌群（AOB和NOB）占有绝对数量优势。

Effects of pH level and nitrifying bacteria concentration on ammonia oxidation rate

To promote the ammonia oxidation rate,the nitrifying bacteria community was enriched in a miniature fermenter by sequence batch processing using the activated sludge taken from the A2/O process of a wastewater treatment plant as the seed sludge. The effects of different levels of free ammonia (FA)at varying pHs on the ammonia oxidation rate,nitrite accumulation,and nitrate production were evaluated. The effects of nitrifying bacterial concentration on the efficiency of ammonia oxidation were also assessed. The results showed that a suitable pH level was crucial to increase the ammonia oxidation rate with a certain initial ammonia concentration,and a relatively high nitrifying bacteria concentration was necessary to improve the ammonia oxidation performance substantially. FISH analysis showed that ammonia-oxidizing and nitrite-oxidizing bacteria were the predominant bacterial groups in the selectively enriched sludge.