Mechanistic insights into CO2 pressure regulating microbial competition in a hydrogen-based membrane biofilm reactor for denitrification

作者：Jiang, Minmin; Zhang, Yuanyuan; Zheng, Junjian^*; Li, Haixiang^*; Ma, Jinxing; Zhang, Xingran; Wei, Qiaoyan; Wang, Xueye; Zhang, Xuehong; Wang, Zhiwei

来源：Chemosphere, 2022, 303: 134875.

DOI：10.1016/j.chemosphere.2022.134875

• Denitrification
• CO2 allocation
• Microbial structure
• Microbial activity

CO2 is a proven pH regulator in hydrogen-based membrane biofilm reactor (H-2-MBfR) but how its pressure regulates microbial competition in this system remains unclear. This work evaluates the CO2 pressure dependent system performance, CO2 allocation, microbial structure and activity of CO2 source H-2-MBfR. The optimum system performance was reached at the CO2 pressure of 0.008 MPa, and this pressure enabled 0.18 g C/(m(2).d) of dissolved inorganic carbon (DIC) allocated to denitrifying bacteria (DNB) for carbon source anabolism and denitrification-related proton compensation, while inducing a bulk liquid pH (pH 7.4) in favor of DNB activity by remaining 0.21 g C/(m(2).d) of DIC as pH buffer. Increasing CO2 pressure from 0.008 to 0.016 MPa caused the markedly changed DNB composition, and the diminished DNB population was accompanied by the enrichment of sulfate-reducing bacteria (SRB). A high CO2 pressure of 0.016 MPa was estimated to induce the enhanced SRB activity and weakened DNB activity.

• 单位
  同济大学; 桂林电子科技大学; 桂林理工大学; 广东工业大学