耐热脱氮菌株的分离鉴定及性能研究

Isolation,identification and characterization of two mesophilic strains for nitrogen removal

摘要:

[目的]为了解决高温的煤化工废水生物脱氮效率不高的技术难题。[方法]本研究从上海某能化集团有限公司的煤化工废水处理系统的活性污泥中筛选得到一株耐热氨氧化细菌A1和一株耐热反硝化细菌D1。[结果]通过形态学观察、生理生化特征及16S rRNA基因序列分析,菌株A1初步鉴定为Aquamicrobium ahrensii,菌株D1初步鉴定为Pseudomonas stutzeri。采用单因子优化实验研究发现,菌株A1和D1的最适生长温度分别高达42℃和40℃。在模拟实际废水处理的初始NH₄⁺-N浓度100 mg/L和42℃的条件下,构建了由菌株A1和D1 (W/W,20%/10%)组成的共培养物,探究该共培养物在不同pH和C/N对短程硝化反硝化脱氮及N₂O的释放效应。结果表明,该共培养物在42℃、pH 9.0–10.0和初始C/N为2:1时,处理模拟废水的氮素去除率达>99.0%,最大N₂O得率高达51.3%。[结论]本研究的结果可为高温煤化工废水的生物处理提供技术支撑及菌种储备,同时也为高温污水处理过程中N₂O的释放规律提供理论参考。

关键词:煤化工废水;耐热氨氧化菌;耐热反硝化菌;分离鉴定;脱氮

Abstract:

[Objective] To address the low efficiency of biological nitrogen removal from high-temperature coal chemical wastewater.[Methods] In this study,a mesophilic ammonia-oxidizing bacterial strain A1 and a mesophilic denitrifying bacterial strain D1 were isolated from the activated sludge of the coal chemical wastewater treatment system of an energy and chemical group Co.Ltd.in Shanghai.[Results] Based on the morphological,physiological,and biochemical characteristics and 16S rRNA gene sequence,strain A1 was preliminarily identified as Aquamicrobium ahrensii and strain D1 as Pseudomonas stutzeri.The single factor experiments showed that the optimal growth temperatures of strains A1 and D1 were as high as 42℃ and 40℃,respectively.Then,we simulated the wastewater treatment at the initial NH₄⁺-N concentration of 100 mg/L and 42℃,and established a co-culture composed of strains A1 and D1(W/W,20%/10%) to explore the effects of the co-culture on shortcut nitrification and denitrification and N₂O release at different pH and C/N ratios.At 42℃,pH 9.0–10.0,and initial C/N ratio of 2:1,the co-culture showed a nitrogen removal rate above 99.0% and the maximum N₂O yield of 51.3%.[Conclusion] This study can provide technological support and strain resources for the biological treatment of high-temperature coal chemical wastewater,and help to reveal the law of N₂O release in the treatment of high-temperature wastewater.

Key words:wastewater of coal chemical industry;mesophilic ammonia-oxidizing bacteria;mesophilic denitrifying bacteria;isolation and identification;nitrogen removal