Comparison of Partial and Full Nitrification Processes Applied for Treating High-Strength Nitrogen Wastewaters: Microbial Ecology through Nitrous Oxide Production
Comparison of Partial and Full Nitrification Processes Applied for Treating High-Strength Nitrogen Wastewaters: Microbial Ecology through Nitrous Oxide Production
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DOI：
10.1021/es103534g
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发表时间：
2011-04-01
影响因子：
11.4
通讯作者：
Chandran, Kartik
中科院分区：
文献类型：
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作者：
Ahn, Joon Ho;Kwan, Tiffany;Chandran, Kartik
本研究的目的是比较的微生物生态，基因表达，bioketry，和N2 O排放量从一个实验室规模的生物反应器连续操作的全硝化和部分硝化模式。基于16 S rRNA和氨单加氧酶亚基A（amoA）基因的测序，氨氧化细菌（AOB）的人口在完全和部分硝化模式是不同的。AOB（X-AOB）的浓度和呼吸速率在完全硝化和部分硝化模式下统计学上相似，而亚硝酸盐氧化细菌（X-NOB）的浓度和呼吸速率在完全硝化切换为部分硝化后显著下降。从完全硝化到部分硝化的过渡导致了一氧化二氮（N2 O）和一氧化氮（NO）排放量的长期瞬态峰值，后来稳定下来。N2 O和NO排放的趋势与编码AOB中这些气体产生的nirK和norB基因表达的趋势相关。无论是瞬态和稳定的N2 O和NO的排放量在短程硝化过程中统计上高于那些在稳态完全硝化。基于这些结果，生物脱氮的部分硝化策略，虽然有吸引力的降低运营成本和能源需求，可能需要优化对较高的碳足迹归因于他们的N2 O排放。
The goal of this study was to compare the microbial ecology, gene expression, biokinetics, and N2O emissions from a lab-scale bioreactor operated sequentially in full-nitrification and partial-nitrification modes. Based on sequencing of 16S rRNA and ammonia monooxygenase subunit A (amoA) genes, ammonia oxidizing bacteria (AOB) populations during full- and partial-nitrification modes were distinct from one another. The concentrations of AOB (X-AOB) and their respiration rates during full- and partial-nitrification modes were statistically similar, whereas the concentrations of nitrite oxidizing bacteria (X-NOB) and their respiration rates declined significantly after the switch from full- to partial-nitrification. The transition from full-nitrification to partial nitrification resulted in a protracted transient spike of nitrous oxide (N2O) and nitric oxide (NO) emissions, which later stabilized. The trends in N2O and NO emissions correlated well with trends in the expression of nirK and norB genes that code for the production of these gases in AOB. Both the transient and stabilized N2O and NO emissions during partial nitrification were statistically higher than those during steady-state full-nitrification. Based on these results, partial nitrification strategies for biological nitrogen removal, although attractive for their reduced operating costs and energy demand, may need to be optimized against the higher carbon foot-print attributed to their N2O emissions.