[Complete nitritation process in an biofilm moving bed system by controlling pH]

Area of Science:

• Environmental microbiology
• Wastewater treatment technologies
• Biofilm processes

Context:

• Nitritation is crucial for nitrogen removal in wastewater treatment.
• Biofilm moving bed reactors offer efficient microbial processes.
• Optimizing operational parameters is key to system stability.

Purpose:

• To investigate the effects of nitrogen loading rate (NLR) and hydraulic retention time (HRT) on complete nitritation.
• To determine optimal conditions for stable nitritation in a biofilm moving bed system.
• To assess system performance under varying operational loads.

Summary:

• Complete nitritation was successfully established within 10 days by controlling pH (7.7-8.2) and other parameters (30°C, DO 1.5-2.0 mg/L, HRT 24h, ammonia 150 mg/L).
• Ammonia conversion exceeded 96% and nitritation rate was over 95% under optimal conditions.
• The system maintained stable nitritation with increased NLR (0.15-0.24 kg/m³·d), showing >90% ammonia conversion and 96% nitritation rate.

Impact:

• Demonstrates the robustness of biofilm moving bed systems for achieving complete nitritation.
• Provides insights into managing operational parameters like NLR and HRT for stable wastewater treatment.
• Highlights the system's ability to recover from process shifts, such as over-aeration, by adjusting HRT.