中文关键词异养硝化细菌反硝化功能基因好氧反硝化脱氮N₂O释放 英文关键词heterotrophic nitrifying bacteriadenitrifying functional genesaerobic denitrificationnitrogen removalN₂O emission

作者	单位	E-mail
杨垒	西安建筑科技大学陕西省环境工程重点实验室, 西安 710055 西安建筑科技大学西北水资源与环境生态教育部重点实验室, 西安 710055	yangleixauat@126.com
崔珅	西安建筑科技大学陕西省环境工程重点实验室, 西安 710055 西安建筑科技大学西北水资源与环境生态教育部重点实验室, 西安 710055
任勇翔	西安建筑科技大学陕西省环境工程重点实验室, 西安 710055 西安建筑科技大学西北水资源与环境生态教育部重点实验室, 西安 710055	ryx@xauat.edu.cn
郭淋凯	西安建筑科技大学陕西省环境工程重点实验室, 西安 710055 西安建筑科技大学西北水资源与环境生态教育部重点实验室, 西安 710055
张志昊	西安建筑科技大学陕西省环境工程重点实验室, 西安 710055 西安建筑科技大学西北水资源与环境生态教育部重点实验室, 西安 710055
肖倩	中国恩菲工程技术有限公司成都分公司, 成都 610000
陈宁	西安建筑科技大学陕西省环境工程重点实验室, 西安 710055 西安建筑科技大学西北水资源与环境生态教育部重点实验室, 西安 710055
汪旭晖	西安建筑科技大学陕西省环境工程重点实验室, 西安 710055 西安建筑科技大学西北水资源与环境生态教育部重点实验室, 西安 710055

中文摘要 由于含氮废水的大量排放，水体富营养化日趋严重，如何高效去除废水中的氮素仍是亟待解决的问题.针对传统生物脱氮工艺流程复杂、能耗高、抗冲击能力弱以及释放温室气体N₂O等缺陷，本文基于高效异养硝化细菌Pseudomonas aeruginosa YL，通过探讨其生理生化特征、异养硝化-好氧反硝化脱氮过程和N₂O产生特性，进一步解析异养硝化脱氮理论.结果表明，菌株YL具有高效的异养硝化和好氧反硝化能力，24 h培养期100 mg·L^-1的NH₄⁺-N、NO₂^--N和NO₃^--N能够完全去除；异养硝化过程几乎无中间产物生成，但以NO₃^--N作为氮源时，NO₂^--N累积量高达25.55 mg·L^-1.同时，反硝化功能基因napA、nirK和nosZ基因的成功表达，进一步证实菌株YL具有好氧反硝化能力.菌株YL异养硝化-好氧反硝化过程气态氮产物约占去除TN的30%~40%，脱氮产物主要为N₂，当NH₄⁺-N、NO₂^--N和NO₃^--N分别为唯一氮源时，N₂生成量分别为3.46、3.49和3.36 mg.相比较，菌株YL脱氮过程仅生成微量的中间产物N₂O，以NH₄⁺-N为唯一氮源时的最终生成总量为6.63 μg，低于以NO₂^--N和NO₃^--N为唯一氮源时N₂O的生成量.此外，高C/N、低pH、高温以及高NH₄⁺-N和NO₂^--N环境均会导致N₂O的大量生成，但大多数环境因素对菌株YL的N₂O生成量影响较小，且其最高生成量显著低于短程硝化系统和自养硝化系统.以上研究结果表明菌株YL具有优异的脱氮、N₂O控逸和环境耐受能力，可有效避免水处理过程对大气的二次污染. 英文摘要 Because of the massive discharge of nitrogenous wastewater, the eutrophication of a water body is becoming increasingly serious, and how to effectively remove nitrogen from this wastewater remains an urgent problem to be solved. In this study, due to disadvantages in the traditional biological nitrogen removal process, such as complex and long procedures, high energy consumption, weak impact resistance, and N₂O release, the nitrogen removal theory by heterotrophic nitrification was further analyzed by discussing the physiological-biochemical, heterotrophic nitrification-aerobic denitrification, and N₂O production characteristics of a high-efficiency heterotrophic nitrifying bacteria Pseudomonas aeruginosa YL. Results show that the strain YL had an eminent heterotrophic nitrification and aerobic denitrification ability, and NH₄⁺-N, NO₂^--N, and NO₃^--N with concentration of 100 mg·L^-1 could be completely removed during the 24-hour incubation period. There was almost no intermediate product in the process of heterotrophic nitrification, however when NO₃^--N was used as nitrogen source, the accumulation of NO₂^--N reached 25.55 mg·L^-1. Meanwhile, the successful expression of denitrification genes napA, nirK, and nosZ further confirmed the aerobic denitrification ability of strain YL. Gaseous nitrogen products accounted for about 30%-40% of removed TN in the heterotrophic nitrification-aerobic denitrification process by strain YL, and N₂ was the main denitrification product. When NH₄⁺-N, NO₂^--N, and NO₃^--N were used as the sole nitrogen source, N₂ production amounted to 3.46, 3.49, and 3.36 mg, respectively. In contrast, only small amounts of N₂O were produced in the denitrification process by strain YL, and the total amount was 6.63 μg when NH₄⁺-N was the nitrogen source, which was much lower than in the cases of NO₂^--N and NO₃^--N as the sole nitrogen source. In addition, high C/N, low pH, high temperature, high NH₄⁺-N, and high NO₂^--N conditions could result in more N₂O generation. Nevertheless, most environmental factors had little effect on N₂O production of strain YL, and the maximum N₂O production was significantly lower than that of short-cut nitrification system and autotrophic nitrification system. These results demonstrated that strain YL exhibited excellent abilities of nitrogen removal, N₂O emission control, and tolerance to environmental conditions, and could be an effective candidate for treating wastewater without secondary air pollution.

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