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Updated: Jan 9, 2026

Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
Advanced nitrogen removal in anaerobic/aerobic/anoxic system under seasonal cooling: enhancing anammox performance in
You Wu1, Hanbin Wang1, Xialian Shi1
1National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China.
Abstract:
The robustness of anaerobic/aerobic/anoxic (AOA) process under low temperature remains insufficiently understood. This study investigated a continuous-flow AOA system while temperature decreased from 27.8 to 15.9 °C. Treating municipal wastewater (total nitrogen (TN) ≈ 75 mg/L; C/N ≈ 3.5), the system achieved a nitrogen removal efficiency (NRE) of 94 % and effluent TN of 4.2 mg/L at 24.7°C. When temperature fell below ∼22 °C, switching Unit 4 from anoxic to aerobic extended the aerobic retention time and sustained an NRE of 87 %, with Unit 4 contributing 13.7 mg/L of nitrogen removal. This adjustment increased biofilm biomass and improved transcription of key anammox genes despite reduced anammox abundance. Kinetic assays showed nitrification supplied nitrite faster than endogenous denitrification. Microbial analysis revealed persistence of oxygen-tolerant Ca. Brocadia (OTU2598 > 97 %). Improved nitrite availability and elevated gene transcription jointly supported stable performance, demonstrating the feasibility of dual-pathway anammox for mainstream treatment in temperate regions.
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