Temperature effects on nitrogen removal and N2O emissions in anammox reactors

Xiaolong Yu; Fumitake Nishimura; Taira Hidaka; Zi-Ang Du; Feng Wang

doi:10.1016/j.biortech.2024.132022

Temperature effects on nitrogen removal and N₂O emissions in anammox reactors

Bioresour Technol. 2024 Dec 26:132022. doi: 10.1016/j.biortech.2024.132022. Online ahead of print.

Authors

Xiaolong Yu¹, Fumitake Nishimura², Taira Hidaka³, Zi-Ang Du³, Feng Wang⁴

Affiliations

¹ College of Environment and Resources, Xiangtan University, Xiangtan 411105, China; School of Environmental Science and Engineering, Southern University of Science and Technology, No.1088, Xueyuan Road, Nanshan District, Shenzhen 518055, China. Electronic address: yuxiaolong@xtu.edu.cn.
² Research Center for Environmental Quality Management, Graduate School of Engineering, Kyoto University, 1-2 Yumihama, Otsu 520-0811, Japan.
³ Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, C1, Kyoto daigaku-Katsura, Kyoto 615-8540, Japan.
⁴ Shanghai Municipal Engineering Design Institute (Group) Co., Ltd., Shanghai 200092, China.

PMID: 39732374
DOI: 10.1016/j.biortech.2024.132022

Abstract

Mainstream anammox faces challenges in adapting to non-optimal temperatures and managing greenhouse gas emissions. This study investigates nitrogen removal and N₂O emissions in attached-growth anammox reactors subjected to rapid temperature shifts (15 - 55 °C). Temperature reductions to 15 - 25 °C had minimal impact on the anammox bacterial populations, with nitrogen removal rates of 0.37 ± 0.11 gN/(L•d) and 0.88 ± 0.10 gN/(L•d) at 15 °C and 25 °C, respectively. In contrast, increasing temperatures to 45 - 55 °C significantly diminished both anammox biomass and bioactivity. The reactor at 35 °C exhibited the lowest N₂O emissions (< 1.0 mgN/(L•d)), while emissions rose to approximately 5.0 mgN/(L•d) at 15 °C and 3.4 mgN/(L•d) at 55 °C (during 295-395 d), primarily due to denitrification performed by coexisting ammonia-oxidizing bacteria and denitrifying microbes. This study provides insights into temperature adaptability and N₂O emission risks, supporting mainstream anammox applications.

Keywords: Anammox bioactivity; Fast adaptation; Greenhouse gas; Mainstream treatment; Temperature shifts.