Nitrogen removal through "Candidatus Brocadia sinica" treating high-salinity and low-temperature wastewater with glycine addition: Enhanced performance and kinetics

Freshwater-derived anaerobic ammonia oxidation (anammox) bacteria ("Candidatus Brocadia sinica") were investigated to remove nitrogen from high-salinity and low-temperature wastewater with glycine addition. The reactor was operated at 15 ± 0.5 °C with influent pH of 7.5 ± 0.1. When glycine were 0.2, 0.4, and 0.6 mM, respectively, nitrite removal rate (NRR) increased by 27.7%, 47.3%, and 70.4% accordingly. Optimal ammonia removal rate (0.32 kg/(m³·d)) and NRR (0.45 kg/(m³·d)) were achieved at 0.8 mM glycine. Effect resulting from glycine on nitrite reductase was higher than hydrazine synthase. Moreover, ΔNO₂^--N/ΔNH₄⁺-N increased with glycine addition while ΔNO₃^--N/ΔNH₄⁺-N first increased and then decreased. The remodified Logistic model and modified Boltzmann model were appropriate to describe nitrogen removal with glycine addition. Kinetic parameter λ achieved through the remodified Logistic model revealed that "Candidatus Brocadia sinica" had a shorter lag phase than that of marine anammox bacteria.