Enhanced nitrogen removal and microbial synergy in a low-energy vibration-assisted membrane bioreactor for urban wastewater treatment

Guiquan Du; Kai Tang; Canhui Song; Hang Yu; Yuheng Zhu; Faqian Sun; Chongjun Chen

doi:10.1016/j.envres.2025.122242

Enhanced nitrogen removal and microbial synergy in a low-energy vibration-assisted membrane bioreactor for urban wastewater treatment

Environ Res. 2025 Jun 25:122242. doi: 10.1016/j.envres.2025.122242. Online ahead of print.

Authors

Guiquan Du¹, Kai Tang¹, Canhui Song², Hang Yu¹, Yuheng Zhu¹, Faqian Sun³, Chongjun Chen⁴

Affiliations

¹ School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China.
² Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aoba, Aramaki-Aza, Sendai, Miyagi 980-8579, Japan; Suzhou Suke Environmental Protection Technology Co., Ltd, Suzhou 215009, PR China.
³ College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, PR China.
⁴ School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, PR China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, PR China. Electronic address: chongjunchen@163.com.

PMID: 40578735
DOI: 10.1016/j.envres.2025.122242

Abstract

Membrane bioreactor (MBR) offers promising solutions for municipal wastewater treatment; however, challenges related to energy consumption and nitrogen removal efficiency persist. In this study, a low-energy partial nitrification MBR (LEP-N-MBR) system-including conventional aeration MBR (AMBR) and equipped with membrane vibration MBR (VMBR)-were evaluated during startup for pollutant removal performance, extracellular polymeric substances (EPS) dynamics, and microbial community structure. Both systems achieved high chemical oxygen demand (COD) and NH₄⁺-N removal, but the VMBR exhibited superior total nitrogen (TN) removal (54.7%) compared to the AMBR (34.2%) due to enhanced denitrification under vibration-induced anoxic conditions. EPS analysis revealed lower protein (PN) content in aerobic pools and increased polysaccharide (PS) accumulation in the MBR compartments, reflecting microbial adaptation and improved sludge floc stability. High-throughput sequencing showed shared enrichment of Proteobacteria and Bacteroidota, while VMBR fostered greater functional bacterial interactions and niche specialization, particularly among denitrifying genera. The novelty of this article lies in linking vibration-induced hydrodynamic conditions to enhanced denitrification through microbial niche specialization and EPS adaptation. This improves the nitrogen removal capacity of energy-efficient MBR systems, increases the potential for microbial resilience, and provides a basis for future large-scale process applications.

Keywords: LEP-N-MBR; microbial community; nitrogen and carbon removal; startup; urban domestic wastewater.