Full-scale simultaneous partial nitrification, anammox, and denitrification for the efficient treatment of carbon and nitrogen in low-C/N wastewater

Water Res X. 2024 Dec 2:26:100288. doi: 10.1016/j.wroa.2024.100288. eCollection 2025 Jan 1.

Abstract

A full-scale simultaneous partial nitrification, anaerobic ammonia oxidation (anammox), and denitrification (SNAD) reactor was initiated to address the problem of high energy consumption for the treatment of low C/N wastewater. The SNAD system achieved a nitrogen removal rate of 0.9 kg/(m3·d) at an influent NH₄+-N concentration of 500 mg/L after 450 days of stable operation. Partial nitrification was achieved by maintaining free ammonia levels at 0.8 ± 0.3 mg/L and dissolved oxygen concentrations between 0.3 mg/L and 1.2 mg/L, which resulted in synergistic nitrogen removal, with anammox contributing 61 % and denitrification contributing 39 %. Microbiological analyses indicated that the dominant microorganisms were Candidatus Brocadia, Thauera, Denitratisoma, and Nitrosomonas. In conclusion, study provides a solid foundation for the broader implementation of the SNAD process in wastewater treatment systems.

Keywords: Anammox; C/N; Denitrification; Partial nitrification; SNAD.