Nitrogen removal and nitrous oxide (N₂O) emission in a lab-scale constant-flow multiple anoxic (A) and aerobic (O) process, combined with the addition of suspended carriers, were investigated. Under steady state, 99.9% of ammonia nitrogen (NH₄-N), 76.8% of orthophosphate, and 80.2% of total inorganic nitrogen removal efficiency was achieved. The N₂O emission factor during nitrification was 0.8–1.9% of the oxidized NH₄-N. The emission factor increased to 7.4–45.9% with the coexistence of heterotrophic activities. Extending the anoxic time from 30 to 90 min reduced the N₂O emission factor from 1.6 to 1.0%. N₂O emission was stimulated with nitrite (NO₂-N) as the electron acceptor, with the N₂O emission factor of 5.2–5.6%. Denitrification with internal organic carbon contributed 6.8% of reduced NO₂-N to N₂O. NO₂-N might exert a crucial role in N₂O emission independent of carbon source. For the acclimated microbial communities, Nitrospira and Nitrosospira were the dominant nitrifiers and responsible for the N₂O emission during nitrification. Azospira, Dechloromonas, Flavobacterium, Pseudomonas, and unclassified genus of family Comamonadaceae might be responsible for N₂O emission during denitrification. These findings may guide the design of multiple AO process for controlling N₂O emission.

研究了实验室规模恒流多重缺氧 (A) 和好氧 (O) 工艺中的脱氮和一氧化二氮 (N ₂ O) 排放，并结合添加悬浮载体进行了研究。在稳定状态下，氨氮（NH ₄ -N）的去除率达到了99.9%，正磷酸盐的去除率达到了 76.8%，无机氮去除率达到了 80.2%。硝化过程中的 N ₂ O 排放因子是氧化的 NH ₄ -N 的0.8-1.9% 。随着异养活动的共存，排放因子增加到7.4-45.9%。将缺氧时间从 30 分钟延长到 90 分钟，N ₂ O 排放因子从 1.6%降低到 1.0%。N ₂ O 排放受亚硝酸盐（NO ₂-N) 作为电子受体，N ₂ O 排放因子为 5.2–5.6%。内部有机碳的反硝化作用将 6.8% 的 NO ₂ -N还原为 N ₂ O。NO ₂ -N 可能在 N ₂ O 排放中发挥关键作用，与碳源无关。对于驯化的微生物群落，Nitrospira和Nitrosospira是主要的硝化菌，负责硝化过程中的 N ₂ O 排放。固氮螺菌属、脱氯单胞菌属、黄杆菌属、假单胞菌属和毛毛藻科未分类属可能是反硝化过程中N ₂ O 排放的原因。这些发现可以指导用于控制 N ₂ O 排放的多个 AO 工艺的设计。