Free nitrous acid and pH determine the predominant ammonia-oxidizing bacteria and amount of N2O in a partial nitrifying reactor
Free nitrous acid and pH determine the predominant ammonia-oxidizing bacteria and amount of N2O in a partial nitrifying reactor
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DOI：
10.1007/s00253-016-7961-2
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发表时间：
2017-02
影响因子：
5
通讯作者：
C. T. Kính;Johwan Ahn;T. Suenaga;Nakanya Sittivorakulpong;P. Noophan;T. Hori;Shohei Riya;M. Hosomi-M.-Hosom
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作者：
C. T. Kính;Johwan Ahn;T. Suenaga;Nakanya Sittivorakulpong;P. Noophan;T. Hori;Shohei Riya;M. Hosomi-M.-Hosom
在实验室规模的序批式反应器中，研究了游离氨（FA）和游离亚硝酸（FNA）浓度对优势氨氧化菌（AOB）和氧化亚氮（N2 O）排放的影响.该反应器的操作与逐步增加的NH 4+负荷率，这导致在最大FA浓度为29.3 mg-N/L，在pH 8.3。之后，FNA随着pH的逐渐降低而增加，在pH 6.3时达到其最大浓度4.1 mg-N/L。荧光原位杂交表明，AOB仍然占主导地位，在操作过程中，实现特定的硝化速率为1.04和0.99克-N/克-VSS/天，在最高积累的FA和FNA，分别。这些速率与> 84%的部分硝化效率相结合。在pH 7.0时，NH 4+氧化的N2 O排放因子为0.90%，高于FA和FNA浓度最高时的pH 8.3（0.11%）和pH 6.3（0.12%）。16 S核糖体RNA基因的高通量测序表明，FNA的增加大大改变了主要的AOB物种，虽然增加FA没有产生显着的变化。本研究表明，FNA浓度和pH值的主要驱动因素，决定了主要的AOB物种和N2 O排放的部分硝化生物反应器。
We investigated the effects of free ammonia (FA) and free nitrous acid (FNA) concentrations on the predominant ammonia-oxidizing bacteria (AOB) and the emission of nitrous oxide (N2O) in a lab-scale sequencing batch reactor for partial nitrification. The reactor was operated with stepwise increases in the NH4+loading rate, which resulted in a maximum FA concentration of 29.3 mg-N/L at pH 8.3. Afterwards, FNA was increased by a gradual decrease of pH, reaching its maximum concentration of 4.1 mg-N/L at pH 6.3. Fluorescence in situ hybridization indicated that AOB remained predominant during the operation, achieving specific nitrification rates of 1.04 and 0.99 g-N/g-VSS/day at the highest accumulations of FA and FNA, respectively. These rates were in conjunction with partial nitrification efficiencies of >84%. The N2O emission factor of oxidized NH4+was 0.90% at pH 7.0, which was higher than those at pH 8.3 (0.11%) and 6.3 (0.12%), the pHs with the maximum FA and FNA concentrations, respectively. High-throughput sequencing of 16S ribosomal RNA genes showed that increases in FNA drastically changed the predominant AOB species, although increased FA produced no significant changes. This study demonstrates that the FNA concentration and pH are the main drivers that determine the predominant AOB species and N2O-emission in a partial nitrifying bioreactor.