| 单级和多级A/O工艺中氮的去除效果及N2O的产生特性 |
| 摘要点击 2398 全文点击 1048 投稿时间：2016-03-20 修订日期：2016-09-07 |
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| 中文关键词 单级A/O 多级A/O 脱氮 氧化亚氮(N2O) 亚硝酸单胞菌属 |
| 英文关键词 single-stage A/O multi-stage A/O nitrogen removal nitrous oxide (N2O) Nitrosomonas |
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| 中文摘要 |
| 利用SBR反应器模拟单级和多级A/O工艺，在进水水质、水力停留时间（HRT）、泥龄（SRT）、温度、缺氧好氧时间比（A/O比）均相同的条件下，考察了两种脱氮系统中氮的去除效果及N2O的释放情况.结果表明，对于与城市污水水质相当的进水水质，单级A/O工艺和多级A/O工艺对COD、氨氮的去除率均在95%以上，二者无明显区别，但是前者对TN的去除效率高于后者，二者的总氮去除率分别为72.1%和52.2%.在氮素的转化过程中，典型周期内（3 h）单级A/O工艺和多级A/O工艺中N2O的产生量分别为16.95 mg和3.59 mg，其转化率（即N2O的产量与TN的去除量之比）分别为11.47%和4.11%，且N2O的产生和释放主要发生在好氧段（硝化阶段），缺氧段（反硝化阶段）基本无N2O释放.单级A/O工艺比多级A/O工艺更有利于硝化细菌（AOB、NOB）的生长，在相同的运行条件下，两工艺中AOB的优势菌种皆为Nitrosomonas，但前者的相对丰度高于后者；单级A/O工艺中NOB的种类和相对丰度也明显多于多级A/O工艺.在实际运行中采用合适的A/O分区或供氧方式既可以较好地去除污水中氮素污染，又可以减少N2O的释放对大气造成二次污染. |
| 英文摘要 |
| 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 N2O 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 N2O were 16.95 mg and 3.95 mg, respectively. The conversion rate, which is the ratio of N2O yield and TN removal, was respectively 11.47% and 4.11%. N2O production and emission occurred mainly in aerobic (nitrification) phase while there was little N2O emission in anoxic (denitrification) phase. Although the dominant species of AOB was both Nitrosomonas 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 Nitrosomonas. 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 N2O to the atmosphere. |
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