title: COD and nitrogen removal and microbial communities in a novel waterfall biofilm reactor operated at different COD/TN ratios.
abstract: The aim of this study was to characterize the pollutant removal efficiency and the microbial communities that arose in a newly designed waterfall biofilm reactor (WFBR) at different chemical oxygen demand/total nitrogen (COD/TN) ratios. The reactor was operated continuously for 28 days at different COD/TN ratios, and its efficiency was evaluated. Results showed that as the thickness of the biofilm increased, the structure of the biofilm encouraged anaerobic-aerobic, anoxic-anaerobic, and fully anaerobic conditions in one reactor. The COD/TN ratios used had a significant effect on the removal of COD and nitrogen components. At a COD/TN ratio of 14, the ammonium nitrogen removal efficiency reached its highest value (99%), but the COD removal efficiency remained at approximately 90%. High-throughput sequencing revealed that the highest community diversity and richness were seen at a COD/TN ratio of 18, and the major phyla were Proteobacteria (average abundance of 47%), Actinobacteria (24%), and Bacteroidetes (13%). As the COD/TN ratios increased from 7 to 18, the abundance of Proteobacteria gradually increased from 25% to 68%. These results could provide important guidance for the design of new wastewater treatment systems and also enrich our theoretical understanding of microbial ecology.
authors: a School of Bioscience and Bioengineering, South China University of Technology , Guangzhou , China.
authors: Siyao
authors: S
authors: Wang
authors: a School of Bioscience and Bioengineering, South China University of Technology , Guangzhou , China.
authors: Yuewu
authors: Y
authors: Pu
authors: b School of Architecture, South China University of Technology, State Key Laboratory of Subtropical Building Science , Guangzhou , China.
authors: Cheng
authors: C
authors: Wei
mesh_terms: D018441:Biofilms; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D058440:Denitrification; D006801:Humans; D009584:Nitrogen / Q000737:chemistry*; D062065:Wastewater; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods
chemical_list: D009584:Nitrogen; D062065:Wastewater
keywords: Biofilm reactor; COD/TN ratios; high-throughput sequencing; microbial community