Heterotrophic bacterium, the strain JQ1004 exhibiting simultaneous nitrification and aerobic denitrification were isolated from activated sludge and identified as Acinetobacter by 16S rDNA. This study was focused on the characteristics of nitrogen removal under aerobic condition by Acinetobacter sp. JQ1004. Clearly, a significant decrease of ammonium and COD was observed by 33h, with 99.45% and 92.54% removal efficiency respectively while NH4+-N was used as sole N-source and sodium succinate was used as organic carbon source. Besides, while the strain utilized NO3--N as nitrogen source, the removal efficiency of NO3--N was 84.42% and total 93.11% of COD was decreased during 34h of incubation. It was interesting to note that higher C/N ratio was required in the degradation of nitrate than ammonium with the same initial concentration under aerobic conditions. Based on the description by modified Compertz model for the experimental data, it was found the isolate using ammonium as a sole nitrogen source showed higher rate of converting nitrogen than using nitrate, with 7.93mg/(L·h) and 4.08mg/(L·h) respectively. Response surface methodology (RSM) experiments proved that efficient nitrogen removal and growth of strain JQ1004occurred with succinate as the carbon source, pH 7.33, 31.80℃, and high C/N ratio of 7.76and dissolved oxygen (with shaking speed of 154.54r/min).%从北京市高碑店污水处理厂BBR(Bacillus Bacteria Bioreactor)中试设备的活性污泥样品中分离得到一株异养硝化-好氧反硝化菌株JQ1004,利用16S rDNA对其进行同源性分析,初步鉴定其为不动杆菌属(Acinetobacter sp.).在好氧条件下,以丁二酸钠为碳源,分别以氨氮和硝酸盐氮为氮源,研究其脱氮特性,发现该菌株在33h时氨氮去除率达到99.45%,COD去除率达到92.54%;在34h时,硝酸盐氮去除率达到84.42%,而COD去除率达到93.11%.另外通过研究发现,与降解氨氮相比,菌株JQ1004在降解硝酸盐氮时需要更高的C/N.利用Compertz模型对其脱氮特性进行拟合发现,菌株对氨氮的最大降解速率明显高于降解硝酸盐氮的最大降解速率,分别为 Rm=7.93mg/(L·h)和Rm=4.08mg/(L·h).利用响应面法进行实验设计,优化其脱氮条件,得到最佳脱氮条件为:pH=7.33;温度=31.80℃;转速=154.54r/min;C/N=7.76.
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