The University of Queensland, Advanced Water Management Centre, St Lucia, QLD 4072, Australia; College of Chemical Engineering, China University of Petroleum, Qingdao 266580, China.
The University of Queensland, Advanced Water Management Centre, St Lucia, QLD 4072, Australia.
Water Res. 2021 Apr 15;194:116963. doi: 10.1016/j.watres.2021.116963. Epub 2021 Feb 23.
Granular sludge exhibits unique features, including rapid settling velocity, high loading rate and relative insensitivity against inhibitors, thus being a favorable platform for the cultivation of slow-growing and vulnerable microorganisms, such as anaerobic ammonium oxidation (anammox) bacteria and nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) microorganisms. While anammox granules have been widely applied, little is known about how to speed up the granulation process of n-DAMO microorganisms, which grow even slower than anammox bacteria. In this study, we used mature anammox granules as biotic carriers to embed n-DAMO microorganisms, which obtained combined anammox + n-DAMO granules within 6 months. The results of whole-granule 16S rRNA gene amplicon sequencing showed the coexistence of anammox bacteria, n-DAMO bacteria and n-DAMO archaea. The microbial stratification along granule radius was further elucidated by cryosection-16S rRNA gene amplicon sequencing, showing the dominance of n-DAMO archaea and anammox bacteria at inner and outer layers, respectively. Moreover, the images of cryosection-fluorescence in situ hybridization (FISH) verified this stratification and also indicated a shift in microbial stratification. Specifically, n-DAMO bacteria and n-DAMO archaea attached to the anammox granule surface initially, which moved to the inner layer after 4-months operation. On the basis of combined anammox + n-DAMO granules, a practically useful nitrogen removal rate (1.0 kg N/m/d) was obtained from sidestream wastewater, which provides new avenue to remove nitrogen from wastewater using methane as carbon source.
颗粒污泥具有独特的特性，包括快速沉降速度、高负荷率和对抑制剂相对不敏感，因此是培养生长缓慢和脆弱的微生物的有利平台，如厌氧氨氧化（anammox）细菌和亚硝酸盐/硝酸盐依赖型厌氧甲烷氧化（n-DAMO）微生物。虽然 anammox 颗粒已被广泛应用，但对于如何加速生长速度比 anammox 细菌更慢的 n-DAMO 微生物的颗粒化过程知之甚少。在本研究中，我们使用成熟的 anammox 颗粒作为生物载体来嵌入 n-DAMO 微生物，在 6 个月内获得了同时具有 anammox 和 n-DAMO 功能的颗粒。全颗粒 16S rRNA 基因扩增子测序的结果表明 anammox 细菌、n-DAMO 细菌和 n-DAMO 古菌共存。通过冷冻切片-16S rRNA 基因扩增子测序进一步阐明了颗粒半径上的微生物分层，结果表明 n-DAMO 古菌和 anammox 细菌分别在内外层占主导地位。此外，冷冻切片-荧光原位杂交（FISH）的图像验证了这种分层，并表明微生物分层发生了变化。具体而言，n-DAMO 细菌和 n-DAMO 古菌最初附着在 anammox 颗粒表面，在 4 个月的运行后移动到内层。在同时具有 anammox 和 n-DAMO 功能的颗粒基础上，从侧流废水中获得了实际有用的脱氮速率（1.0 kg N/m/d），为利用甲烷作为碳源从废水中去除氮提供了新途径。
