Effect of zero-valent iron (ZVI) on nitrogen and Fe(II) metabolism in anammox-hydroxyapatite (HAP) system under low-temperature stress

• Published in: Journal of environmental chemical engineering 2024-10, Vol.12 (5), p.113998, Article 113998
• Main Authors: Liu, Lingjie, Mo, Shaoqing, Wang, Shaopo, Chang, Jing, Zhao, Jianhui, Yu, Jingjie
• Format: Article
• Language: English
• Subjects: Anammox; Iron metabolism; Low-temperature shock; Metagenomic analysis; Zero-valent iron
• ISSN: 2213-3437
• DOI: 10.1016/j.jece.2024.113998

Low temperatures could inhibit the activity of anaerobic ammonium oxidizing bacteria (AnAOB). This study investigated the effect of exogenous zero-valent iron (ZVI) on Anammox-hydroxyapatite (HAP) system at 17 ± 1 °C. The results showed that long-term addition of ZVI increased the nitrogen removal efficiency by 8.59 %, and alleviated the inhibition of AnAOB under the condition of low temperature. After addition of ZVI, the activity of AnAOB and the heme c content increased by 58.20 % and 4.83 %, respectively. Moreover, the functional enzyme activities of NIR, HZS, and HZO increased by 94.12 %, 36.36 %, and 16.67 %, respectively. The concentrations of quorum sensing molecules, i.e., C6-HSL and C8-HSL, increased by 191.17 % and 41.54 %, respectively, after ZVI addition. Metagenomic analysis revealed that the addition of 5 g/L ZVI stimulated the relative abundance of Fe(II) metabolism-related genes in AnAOB at 17 ± 1 °C, thereby contributing to the uptake, transport, utilization, and storage of Fe(II). In summary, the addition of ZVI could improve the nitrogen removal performance of the anammox-HAP system at the low temperature. [Display omitted] •5 g/L ZVI promoted the nitrogen removal performance of Anammox-HAP system at 17°C.•Microbial quorum sensing was enhanced after ZVI addition under low-temperature shock.•ZVI could enhance utilization, transport, utilization, and storage of Fe(II) in anammox consortia.