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异养硝化细菌Pseudomonas aeruginosa YL的脱氮过程及N2O产生特性

本站小编 Free考研考试/2021-12-31

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napAnirKnosZ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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