Partial denitrification (PD) can supply essential nitrite (NO₂^-) and is supposed to promote the application of Anammox. However, PD-related research mainly involves sequencing batch reactors and activated sludge. Here, we proposed establishing PD in a continuous-flow submerged biofilm module (PD-BfM). Benefiting from employing anoxic starvation treatment to quickly start PD and transferring enriched functional bacteria onto biofilms in time, the preparation work of PD-BfM was completed within a quite short period of 21 days. With the hydraulic retention time adjusted to 50 min, PD-BfM demonstrated an impressive efficiency in generating NO₂^-, achieving a nitrate-to-nitrite transformation ratio of over 75 %, even at the influent chemical oxygen demand to nitrate ratio of 4 condition. Meanwhile, the dominant genus in the biofilms was shifted from Thauera to Flavobacterium and Comamonadaceae family members. The gradient of substrate concentrations also possibly differentiated microbial communities between the top and bottom bio-carriers.

中文翻译：

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建立水力停留时间短的连续流部分反硝化生物膜模块


部分反硝化 （PD） 可以提供必需的亚硝酸盐 （NO₂^-），并应该促进厌氧氨氧化的应用。然而，PD 相关研究主要涉及序批式反应器和活性污泥。在这里，我们建议在连续流浸没式生物膜模块 （PD-BfM） 中建立 PD。得益于采用缺氧饥饿处理快速启动 PD 并及时将丰富的功能菌转移到生物膜上，PD-BfM 的制备工作在很短的 21 天内完成。将水力停留时间调整到 50 分钟后，PD-BfM 在生成 NO₂^- 方面表现出令人印象深刻的效率，即使在进水化学需氧量与硝酸盐比为 4 的条件下，硝酸盐转化为亚硝酸盐的转化率也超过 75%。同时，生物膜中的优势属从 Thauera 转移到 Flavobacterium 和 Comamonadaceae 家族成员。底物浓度的梯度也可能区分顶部和底部生物载体之间的微生物群落。