Pioneering on single-sludge nitrification/denitrification at 50 °C.

Area of Science:

• Environmental Microbiology
• Wastewater Treatment Engineering
• Bioreactor Technology

Background:

• Thermophilic nitrification is established at 50°C in lab bioreactors.
• Integrating nitrification with denitrification and carbon removal for thermophilic nitrogen removal remains a challenge.

Purpose of the Study:

• To develop a single-sludge nitrification/denitrification process operating at 50°C.
• To assess the tolerance of nitrifying communities to anoxia and organic carbon.

Main Methods:

• Long-term membrane bioreactor (MBR) operation to test anoxia tolerance.
• Batch flask incubations to evaluate organic carbon impact on nitrification.
• Sequencing batch reactor (SBR) and MBR tests at increasing COD/N ratios.

Main Results:

• Nitrifying communities tolerated recurrent anoxia with >98% ammonium oxidation.
• Organic carbon sources did not inhibit thermophilic nitrification rates.
• Combined nitrification and denitrification achieved 92-100% nitrogen removal efficiency.

Conclusions:

• Thermophilic nitrifiers can adapt to redox fluctuations and organic carbon presence.
• Functional coexistence of nitrifiers and heterotrophs is possible.
• Single-sludge thermophilic nitrification/denitrification is achievable.