| 高盐高碱环境下硝化反硝化过程及N2O产生特征 |
| 摘要点击 1340 全文点击 477 投稿时间：2018-11-06 修订日期：2019-03-04 |
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| 中文关键词 高盐高碱 硝化反硝化 N2O 序批式生物膜反应器(SBBR) 高通量测序 |
| 英文关键词 saline and alkaline conditions nitrification and denitrification N2O sequencing batch biofilm reactor (SBBR) high-throughput sequencing |
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| 中文摘要 |
| 采用稳定运行在高盐高碱环境厌氧/好氧/缺氧（An/O/A）模式下的序批式生物膜反应器（SBBR），考察在不同碳氮比（C/N）条件下，硝化反硝化过程及N2O产生特征.结果表明，在C/N为5、2和对照组（C/N=0）时，总氮去除率分别为（98.17±0.42）%、（65.78±2.47）%和（44.08±0.27）%； N2O的产生量分别为（32.07±2.03）、（21.81±0.85）和（17.32±0.95） mg·L-1； N2O转化率（N2O产生量在去除总氮中的比例）分别为（29.75±0.93）%、（30.04±2.17）%和（41.69±0.80）%.高盐高碱条件下，亚硝酸盐氧化菌（NOB）受到很强的抑制作用，硝化过程基本停留在亚硝酸盐阶段.由于高盐高碱环境对N2O还原酶活性的抑制，使得异养反硝化过程产生了大量N2O，随着碳氮比的增大，有更多的碳源用于反硝化过程，因而总氮去除率和N2O产生量均随之增加.随着碳氮比的增大，N2O转化率随之降低，这可能是由于异养反硝化过程氮素还原酶对电子的竞争所形成的，碳氮比越高，电子竞争越弱.高通量测序表明：在SBBR中，氨氧化细菌（AOB）被富集，而几乎不存在NOB；优势异养反硝化菌属主要是Thauera、Azoarcus和Gemmobacter. |
| 英文摘要 |
| A sequencing biofilm batch reactor (SBBR) running continuously in an anaerobic/aerobic/anoxic (An/O/A) mode was adopted to study the characteristics of nitrification and denitrification process and nitrous oxide (N2O) production under high saline and alkaline conditions. Different carbon and nitrogen ratios (C/N) were also investigated. An influent C/N ratio of 5, 2, and 0 (control), achieved the following results:TN removal efficiency was (98.17±0.42)%, (65.78±2.47)%, and (44.08±0.27)%, respectively; total N2O production was (32.07±2.03) mg·L-1, (21.81±0.85) mg·L-1, and (17.32±0.95) mg·L-1, respectively; and the N2O conversion rate (i. e., the ratio of total N2O production to total nitrogen removal) was (29.75±0.93)%, (30.04±2.17)%, and (41.69±0.80)%, respectively. The nitrification process proceeded normally during the nitrite stage, and nitrite-oxidizing bacteria (NOB) were strongly inhibited under the high saline and alkaline conditions. Due to the inhibition of N2O reductase under these conditions, N2O production was higher during the heterotrophic denitrification process than during the ammonia oxidation process. With an increase in the carbon to nitrogen ratio, more carbon sources were available for denitrification meaning that the total nitrogen removal rate and N2O production were both increased. As the ratio of carbon to nitrogen was increased, the N2O conversion rate decreased, which may have been caused by electron competition among the nitrogen oxide reductases during the denitrification process; the higher the ratio of carbon to nitrogen, the weaker the electron competition. High-throughput sequencing indicated that ammonium-oxidizing bacteria (AOB) were enriched and NOB were almost entirely absent in the SBBR. Thauera, Azoarcus, and Gemmobacter were the dominant heterotrophic denitrifying bacteria identified in the system. |
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