| A2/O与倒置A2/O工艺低温条件下的氨氮去除能力解析 |
| 摘要点击 6257 全文点击 842 投稿时间：2020-11-18 修订日期：2021-01-10 |
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| 中文关键词 倒置A2/O 氨氧化细菌 克隆文库 COD负荷 低温 |
| 英文关键词 inverted A2/O ammonia-oxidizing bacteria clone library COD load low temperature |
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| 中文摘要 |
| 对相同进水、平行运行的A2/O与倒置A2/O工艺的冬季氨氮（NH4+-N）去除能力进行了全面解析.在运行水温为14℃时，倒置A2/O工艺表现出更低的NH4+-N容积去除负荷［0.13 kg·（m3·d）-1和0.29 kg·（m3·d）-1］和氨氧化速率（AOR）［0.07 kg·（kg·d）-1和0.11 kg·（kg·d）-1］，而26℃时两个工艺则相差无几.两个平行工艺中的氨氧化菌（AOB）种群定量结果几乎始终相等（倒置A2/O工艺为3.2%±0.24%，A2/O工艺为3.4%±0.31%）.克隆文库分析的结果表明，造成低温时倒置A2/O工艺中具有较低氨氮去除能力的原因是其AOB优势种属为AOR较慢的慢生型（K-生长策略）亚硝化螺菌属（Nitrosospira），而在A2/O工艺中则为AOR较快的快生型（r-生长策略）亚硝化单胞菌属（Nitrosomonas）；而在26℃环境下两个工艺中的优势种属则均为Nitrosomonas.结合对污染物沿程去除过程的全面分析，发现尽管温度是决定AOB优势种属演替的首要原因，但由于倒置A2/O的工艺结构变化造成其好氧单元具有较高的COD负荷和高NH4+-N浓度等不利于AOB生长的因素，决定了其可以在常规城市污水的条件下出现K-生长策略型的优势AOB种属.因此倒置A2/O针对异养菌（聚磷菌与反硝化菌）的工艺构造变化却通过COD负荷等间接影响到自养型氨氧化菌的种群分布与演替，并最终造成工艺在低温条件下硝化能力的减弱. |
| 英文摘要 |
| Ammonia nitrogen (NH4+-N) removal capacities of the A2/O and inverted A2/O processes were analyzed with the same inlet and parallel operation during winter. When the operating water temperature was 14℃, the inverted A2/O process exhibited lower NH4+-N removal from the volumetric load[0.13 kg ·(m3 ·d)-1vs. 0.29 kg ·(m3 ·d)-1] and a lower ammonia oxidation rate (AOR)[0.07 kg ·(kg ·d)-1 vs. 0.11 kg ·(kg ·d)-1] than the A2/O process, whereas the two processes exhibited similar performance at 26℃.The quantitative results for the ammonia oxidizing bacteria (AOB) population were almost the same in the two parallel processes (3.2%±0.24% for the inverted A2/O process and 3.4%±0.31% for the A2/O process). Clone library analysis showed that at low temperatures, the inverted A2/O process had a lower capacity for ammonia nitrogen removal than A2/O process. This is because the particular AOB species[spirillum (Nitrosospira)] facilitated the slower AOR type (K-growth strategy) of nitrosation in the inverted A2/O process, whereas in the A2/O process, the faster AOR type (r-growth strategy) of nitrosation was facilitated by bacterium (Nitrosomonas). At 26℃, the dominant species in the two processes were Nitrosomonas. Through comprehensive analysis of the pollutants during the removal process, we found that although temperature is the leading cause of AOB advantage in species succession, the changes in the inverted A2/O process structure, caused by the aerobic unit, resulted in high COD load and high NH4+-N concentration, which were unfavorable for the growth of AOB. This shows that under conventional sewage conditions, the K-growth strategy is advantageous for the AOB species. Therefore, the structure of the inverted A2/O process for heterotrophic bacteria (phosphorus accumulating bacteria and denitrifying bacteria) indirectly affects the population distribution and succession of autotrophic ammonia-oxidizing bacteria, through COD load and other factors, thereby leading to weakened nitrification capacity at low temperatures. |
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