Evaluating the performance and stability of microalgal-bacterial granular sludge in municipal wastewater treatment plants

Yuting Shi; Chao Du; Bingheng Chen; Bingyi Ding; Anjie Li; Bin Ji

doi:10.1016/j.jenvman.2024.123912

Evaluating the performance and stability of microalgal-bacterial granular sludge in municipal wastewater treatment plants

J Environ Manage. 2024 Dec 27:373:123912. doi: 10.1016/j.jenvman.2024.123912. Online ahead of print.

Authors

Yuting Shi¹, Chao Du², Bingheng Chen², Bingyi Ding², Anjie Li³, Bin Ji⁴

Affiliations

¹ Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, China; Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources, School of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan, 430065, China.
² Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, China.
³ Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
⁴ Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan, 430065, China. Electronic address: binji@wust.edu.cn.

PMID: 39731956
DOI: 10.1016/j.jenvman.2024.123912

Abstract

The microalgal-bacterial granular sludge (MBGS) process shows potential for carbon-neutral wastewater treatment, yet its application in wastewater treatment plants remains underexplored. This study attempted to use a continuous-flow raceway reactor to treat real municipal wastewater using the MBGS process. The results showed that the removal efficiencies of organics peaked on the fifth day, while declining trends were observed for nitrogen and phosphorus removal. Microbial community and functional gene analyses indicated that the removal of organics, nitrogen, and phosphorus might be heavily influenced by Proteobacteria, suggesting that fluctuations in their abundance significantly impacted the performance of MBGS. Bacteroidota and Actinobacteria played a vital role in cellulose decomposition via the cbhA gene. Moreover, energy shortages caused by light attenuation due to wastewater turbidity and environmental fluctuations disrupted the microbial balance, shifting metabolic activity towards carbon pathways. Key challenges for the broader application of the MBGS process include managing wastewater turbidity and ensuring process stability. These findings highlight the need for pretreatment measures and robust operational strategies to mitigate environmental fluctuations and maintain system performance.

Keywords: Carbon metabolism; Environmental fluctuations; Light attenuation; Outdoor performance; Wastewater turbidity.