Discovering dominant ammonia assimilation: Implication for high-strength nitrogen removal in full scale biological treatment of landfill leachate
Discovering dominant ammonia assimilation: Implication for high-strength nitrogen removal in full scale biological treatment of landfill leachate
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发现主要的氨同化作用：对垃圾渗滤液全面生物处理中高强度脱氮的影响
DOI：
10.1016/j.chemosphere.2022.137256
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发表时间：
2022
期刊：
影响因子：
8.8
通讯作者：
Gang Xue
中科院分区：
文献类型：
--
作者：
Lei Xu;Yuting Chen;Zheng Wang;Yu Zhang;Yueling He;Ai Zhang;Hong Chen;Gang Xue
生活垃圾填埋过程中会产生含有高浓度氮的垃圾渗滤液。以硝化反硝化为基础的缺氧好氧工艺（AO）已成为生物脱氮的主流工艺。但高浓度的有机物以及好氧出水回流可能会改变AO设计和运行的生化环境。针对垃圾渗滤液两级AO处理厂的氮平衡，研究发现，总氮（TN）和氨氮（NH 4 +-N）的去除约90%集中在一级缺氧和好氧阶段。同时，好氧出水中较少的硝酸盐和亚硝酸盐不能维持反硝化或厌氧氨氧化（anammox）。从好氧到缺氧工艺的高回流使得缺氧和好氧工艺单元中的微生物群落和功能基因相似。然而，在所有的过程单元中，涉及氨同化的功能基因表现出最高的丰度相比，与其他BNR途径，包括硝化和反硝化，同化和异化硝酸盐还原，固氮和厌氧氨氧化。氨同化作用对TN和NH 4 +-N的去除起主导作用，而非其他生物固氮机制。优势氨同化作用的认识有利于揭示AO填埋场渗滤液BNR的真实机理，从而指导工程设计和运行的优化。
Landfill leachate containing high-strength nitrogen is generated in domestic waste landfilling. The integration of anoxic and aerobic process (AO) based on nitrification and denitrification, has been a mainstream process of biological nitrogen removal (BNR). But the high-strength organics as well as aerobic effluent reflux might change the biochemical environment designed and operated as AO. In view of the nitrogen balance in a full scale landfill leachate treatment plant with two-stage AO, we found that approximately 90% removal of total nitrogen (TN) and ammonia (NH4+-N) focused on primary anoxic and aerobic stage. Meanwhile, the less nitrate and nitrite in the aerobic effluent were incapable of sustaining denitrification or anaerobic ammonia oxidation (anammox). The high reflux flow from aerobic to anoxic process enabled the similar microbial community and functional genes in anoxic and aerobic process units. However, the functional genes involving ammonia assimilation in all process units showcased the highest abundance compared to those correlated with other BNR pathways, including nitrification and denitrification, assimilatory and dissimilatory nitrate reduction,nitrogen fixation and anammox. The ammonia assimilation dominated the removals of TN and NH4+-N, rather than other BNR mechanism. The insight of dominant ammonia assimilation is favorable for illustrating the authentic BNR mechanism of landfill leachate in AO, thereby guiding the optimization of engineering design and operation.