The one-stage partial nitritation-anammox (PN-A) process is considered an efficient process for low-cost nitrogen removal. In this study, the nitrogen removal performance of different-sized granules in a one-stage PN-A reactor was studied. The total autotrophic nitrogen removal rate (TANRR) of the granular sludge increased as the granule size increased, and the TANRR of granular sludge with a radius larger than 500 μm reached 0.14 kgN kgVSS-1 d-1. High-throughput sequencing revealed that the abundance of ammonium-oxidizing bacteria and anaerobic ammonium-oxidizing (anammox) bacteria in granular sludge of different sizes differed, indicating that the bacterial community structure was affected by the granule size. The TANRR of different-sized granules was affected by the volumes of aerobic micro-zone and anaerobic micro-zone inside the granule. Appropriate micro-zone volumes inside the granules could be regulated by the dissolved oxygen (DO) concentration of the reactor, which are favourable for achieving a balance between partial nitritation and anammox and then satisfactory nitrogen removal. Small-volume variations in the range of micro-zones have a significant influence on the balance between partial nitritation and anammox. The proper DO concentration required for different-sized granules to achieve better nitrogen removal differed. This study provides a novel perspective for understanding the effect of micro-zones of granular sludge on one-stage PN-A nitrogen removal.

中文翻译：

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评价颗粒污泥的微区对一阶段部分硝化-氨氧化氮去除的影响。

一阶段的部分硝化-厌氧氨（PN-A）工艺被认为是低成本脱氮的有效工艺。在这项研究中，研究了一级PN-A反应器中不同尺寸颗粒的脱氮性能。颗粒污泥的总自养氮去除率（TANRR）随颗粒尺寸的增加而增加，半径大于500μm的颗粒污泥的TANRR达到0.14 kgN kgVSS-1 d-1。高通量测序表明，不同大小的颗粒污泥中氨氧化细菌和厌氧铵氧化（anammox）细菌的丰度有所不同，这表明细菌群落结构受颗粒大小的影响。不同大小颗粒的TANRR受颗粒内部需氧微区和厌氧微区体积的影响。颗粒内部适当的微区体积可以通过反应器的溶解氧（DO）浓度来调节，这有利于实现部分硝化和厌氧氨氮之间的平衡，然后实现令人满意的脱氮。微区范围内的小体积变化对部分硝化和厌氧氨氧化之间的平衡有重大影响。为实现更好的脱氮效果，不同大小的颗粒所需的合适的溶解氧浓度有所不同。这项研究为理解颗粒污泥的微区对一级PN-A脱氮的影响提供了新的视角。有利于在部分硝化和厌氧氨氮之间取得平衡，然后令人满意地脱氮。微区范围内的小体积变化对部分硝化和厌氧氨氧化之间的平衡有重大影响。为实现更好的脱氮效果，不同大小的颗粒所需的合适的溶解氧浓度有所不同。这项研究为理解颗粒污泥的微区对一级PN-A脱氮的影响提供了新的视角。有利于在部分硝化和厌氧氨氮之间取得平衡，然后令人满意地脱氮。微区范围内的小体积变化对部分硝化和厌氧氨氧化之间的平衡有重大影响。为实现更好的脱氮效果，不同大小的颗粒所需的合适的溶解氧浓度有所不同。这项研究为理解颗粒污泥的微区对一级PN-A脱氮的影响提供了新的视角。