Guo Chang-Zi, Zhang Feng-Yan, Liu Fu-Yu, Zhu Chao, Pei Li-Ying
School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China.
Huan Jing Ke Xue. 2017 Feb 8;38(2):647-653. doi: 10.13227/j.hjkx.201603152.
The single-stage A/O and multi-stage A/O processes were simulated by sequencing batch reactors (SBRs) with alternate stirring and aeration. The removal efficiency of nitrogen and the release mechanism of NO were studied under the identical conditions of influent quality, hydraulic retention time (HRT), sludge retention time(SRT), temperature and anoxic/oxic (A/O) retention time ratio. Experimental results showed that COD or ammonia-nitrogen removal had no significant difference between the single-stage and the multi-stage A/O processes for the influent quality equivalent to municipal wastewater. However, TN removal efficiency of the former was better than the later with 72.1% and 52.2%, respectively. In the conversion of total nitrogen, during the typical cycle in the single-stage A/O and multi-stage A/O processes, the yields of NO were 16.95 mg and 3.95 mg, respectively. The conversion rate, which is the ratio of NO yield and TN removal, was respectively 11.47% and 4.11%. NO production and emission occurred mainly in aerobic (nitrification) phase while there was little NO emission in anoxic (denitrification) phase. Although the dominant species of AOB was both in the single-stage A/O and the multi-stage A/O processes under the same operating conditions, it was more conducive to the growth of nitrifying bacteria (AOB, NOB) in the single-stage A/O process with the greater abundance of . Meanwhile, the type and abundance of NOB in the single-stage A/O process were significantly more than in the multi-stage A/O process too. Therefore, it is more competitive to deal with the high-strengthening ammonia-nitrogen wastewater in the single-stage A/O process. In the actual operation of wastewater treatment, using appropriate partitions of A/O or oxygen-supplying modes can not only result in better nitrogen removal but also decrease the secondary pollution caused by NO to the atmosphere.
采用序批式反应器（SBR），通过交替搅拌和曝气模拟单级A/O和多级A/O工艺。在进水水质、水力停留时间（HRT）、污泥停留时间（SRT）、温度和缺氧/好氧（A/O）停留时间比相同的条件下，研究了氮的去除效率和NO的释放机制。实验结果表明，对于相当于城市污水的进水水质，单级和多级A/O工艺在COD或氨氮去除方面没有显著差异。然而，前者的TN去除效率优于后者，分别为72.1%和52.2%。在总氮转化过程中，单级A/O和多级A/O工艺的典型周期内，NO的产量分别为16.95mg和3.95mg。转化率（即NO产量与TN去除量之比）分别为11.47%和4.11%。NO的产生和排放主要发生在好氧（硝化）阶段，而在缺氧（反硝化）阶段几乎没有NO排放。尽管在相同运行条件下，单级A/O和多级A/O工艺中AOB的优势菌种相同，但单级A/O工艺中硝化细菌（AOB、NOB）的丰度更高，更有利于其生长。同时，单级A/O工艺中NOB的种类和丰度也明显多于多级A/O工艺。因此，单级A/O工艺处理高浓度氨氮废水更具竞争力。在污水处理的实际运行中，采用合适的A/O分区或供氧方式，不仅可以实现更好的脱氮效果，还可以减少NO对大气造成的二次污染。
