Work

Significance of Influent C/N Ratios in Mainstream Anammox Process: Nitrogen Removal and Microbial Dynamics

Year: 2025

Type: article

Abstract: Achieving simultaneous anammox and denitrification is a feasible approach for enhancing nitrogen removal in mainstream anammox processes. Nevertheless, the optimal C/N range and microbial dynamics driving this process are still not fully understood. In this study, three mainstream anammox reactors were operated with varying influent C/N ratios. The results demonstrated a remarkable nitrogen removal of 92.6% achieved by combining partial denitrification and anammox with the C/N ratio set at 1.0. However, the nitrogen removal efficiency decreased when the C/N ratio was either 0.5 or 2.0, causing the accumulation of nitrate and ammonium in the effluent, respectively. These results suggest a narrow optimal range of the influent C/N for mainstream anammox processes. Additionally, a transition in the predominant denitrifier population from Denitratisoma to Thauera was noted when the C/N ratio increased. The denitrifying phenotype of Thauera was significantly influenced by the C/N ratio. Thauera can effectively collaborate with anammox bacteria only at a suitable C/N ratio, where it partially reduces the nitrate generated in the anammox reaction. With a high influent C/N, Thauera primarily performed nitrite reduction, notably inhibiting anammox activity. The results of this study are valuable for the optimal design of the mainstream anammox process.

Source: Water

DOI: 10.3390/w17040562

Authors: Yandong Yang, Shichong Liu, Lei Liu, Yanan Long, Chao Wang, Changqing Liu

Institution: Qingdao University of Technology

Language: English

Topic: Wastewater Treatment and Nitrogen Removal

Subfield: Pollution

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: gold

Estimated APC paid: $3,137