Shortcut nitrification-denitrification and population dynamics of nitrifying bacteria in MUCT process treating domestic wastewater

doi:10.11949/j.issn.0438-1157.20151853

Abstract

Abstract:

Shortcut nitrification-denitrification and population dynamics of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) were investigated in a continuous flow MUCT reactor treating real domestic wastewater. Shortcut nitrification-denitrification was achieved by controlling low dissolved oxygen (DO) concentration of 0.5 mg·L^-1 and short hydraulic retention time (HRT) of 6 h. Nitrite accumulation ratios reached above 90%. TN removal in the phase of shortcut nitrification-denitrification was up to 90%, far higher than complete nitrification with 74% of TN removal. The results of quantitative real time PCR (QPCR) indicated that during complete nitrification-denitrification AOB abundance exhibited a decline tendency, decreasing from 1.69×10⁹ cells·(g dried sludge)^-1 to 3.76×10⁷ cells·(g dried sludge)^-1, and NOB abundance maintained at 10⁸ cells·(g dried sludge)^-1. During shortcut nitrification-denitrification, the abundance of AOB slightly increased from 3.17×10⁶ cells·(g dried sludge)^-1 to 1.32×10⁷ cells·(g dried sludge)^-1 accompanied with a slight increase of ratio of AOB to total bacteria. The abundance of NOB fluctuated in a range of 5.9×10⁷-1.78×10⁸ cells·(g dried sludge)^-1. The ratio of NOB to total bacteria dropped from 1.44% to 0.47%. Therefore, the abundance decrease and bioactivities inhibition of NOB were the important factors to achieve shortcut nitrification-denitrification in MUCT process treating real domestic wastewater. During shortcut nitrification-denitrification due to low DO concentration and short HRT, AOB abundance and their relative distribution did not increase, even descended. But that did not influence the removal of ammonia and total nitrogen.

Key words: domestic wastewater, ammonia oxidizing bacteria, nitrite oxidizing bacteria, shortcut nitrification- denitrification, complete nitrification-denitrification, real time quantitative PCR

摘要：

采用连续流MUCT工艺处理实际生活污水,研究短程生物脱氮的实现,并采用实时荧光定量PCR方法(quantitative real time PCR,QPCR)分析全程脱氮向短程脱氮转变过程中氨氧化细菌(ammonia-oxidizing bacteria,AOB)和亚硝酸盐氧化菌(nitrite-oxidizing bacteria,NOB)的动态变化。通过降低溶解氧浓度为0.5mg·L^-1和缩短水力停留时间为6h,实现短程硝化,亚硝酸盐积累率达到90%。在短程硝化稳定运行阶段总氮去除率高达90%以上,远远大于全程阶段的74%。QPCR结果表明全程脱氮阶段水力停留时间的缩短使AOB细胞数呈现下降的趋势,NOB细胞总数稳定维持在10⁸cells·(g dried sludge)^-1。短程脱氮阶段,AOB细胞数小幅度上升,由3.17×10⁶cells·(g dried sludge)^-1增长到1.32×10⁷cells·(g dried sludge)^-1,同时AOB占全菌的比例也小幅度增长。NOB的细胞数在5.9×10⁷~1.78×10⁸cells·(g dried sludge)^-1之间波动。NOB占全菌的比例由1.44%下降到0.47%。因此,MUCT工艺处理实际生活污水的系统中NOB丰度降低及活性抑制是实现并维持短程生物脱氮的重要原因。短程脱氮运行期间由于控制低溶解氧浓度和短的水力停留时间,AOB丰度及相对含量没有显著增加,甚至下降,但不会影响氨氮和总氮的去除。

关键词: 生活污水, 氨氧化细菌, 亚硝酸盐氧化菌, 短程脱氮, 全程脱氮, 实时荧光定量PCR

CLC Number:

X703.1

ZENG Wei, ZHANG Jie, JI Zhaohua, WANG Anqi, PENG Yongzhen. Shortcut nitrification-denitrification and population dynamics of nitrifying bacteria in MUCT process treating domestic wastewater[J]. CIESC Journal, 2016, 67(6): 2533-2541.

曾薇, 张洁, 纪兆华, 王安其, 彭永臻. MUCT工艺处理生活污水短程脱氮的实现及硝化菌群动态变化[J]. 化工学报, 2016, 67(6): 2533-2541.

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