Nutrient removal in an A2O-MBR reactor with sludge reduction

Area of Science:

• Environmental Engineering
• Wastewater Treatment Technologies
• Resource Recovery

Background:

• Conventional wastewater treatment generates significant excess sludge.
• Phosphorus discharge from wastewater poses environmental risks.
• Integrated processes are needed for sustainable sludge and nutrient management.

Purpose of the Study:

• To develop and evaluate an advanced A2O-MBR process for simultaneous excess sludge reduction and phosphorus recovery.
• To assess the impact of integrated sludge digestion on overall treatment efficiency.
• To demonstrate the long-term operational stability of the proposed system.

Main Methods:

• An advanced anaerobic-anoxic-oxic Membrane Bioreactor (A2O-MBR) was operated for 210 days.
• Thermochemical sludge digestion was performed at pH 11 and 75°C for 25% COD solubilization.
• Released phosphorus was recovered via precipitation, with organics recycled to the anoxic tank.

Main Results:

• The A2O-MBR process effectively reduced excess sludge production.
• Phosphorus recovery was achieved through the integrated thermochemical digestion and precipitation.
• Chemical Oxygen Demand (COD) and Total Phosphorus (TP) removal efficiencies remained high.
• Membrane Bioreactor (MBR) transmembrane pressure remained stable throughout the operation.

Conclusions:

• The integrated A2O-MBR process offers a viable solution for reducing excess sludge in wastewater treatment.
• Simultaneous phosphorus recovery is feasible without negatively impacting effluent quality.
• The developed process configuration demonstrates potential for sustainable and efficient wastewater management.