Enhanced biological nutrient removal using MUCT-MBR system.

Area of Science:

• Environmental Science
• Microbiology
• Chemical Engineering

Background:

• Biological nutrient removal is crucial for wastewater treatment.
• Combined systems like modified University of Cape Town (mUCT) and membrane bioreactors (MBR) are employed for enhanced performance.
• Optimizing conditions for nutrient removal, particularly phosphorus, is an ongoing challenge.

Purpose of the Study:

• To investigate biological nutrient removal efficiencies in a combined mUCT-MBR system.
• To evaluate the impact of different electron acceptors (nitrite vs. nitrate) on nutrient removal and sludge yield.
• To determine the contribution of denitrifying phosphorus removal.

Main Methods:

• Utilized a combined modified University of Cape Town and membrane bioreactor system.
• Investigated performance across varying influent nutrient mass ratios (COD/TN/TP).
• Conducted batch tests to assess the proportion of denitrifying phosphorus-accumulating organisms.

Main Results:

• Achieved average removal efficiencies of 90% for COD, 81.6% for TN, and 75.2% for TP.
• Observed significant denitrifying phosphorus removal, especially when nitrite was the electron acceptor (99.8% phosphate uptake).
• Nitrite as electron acceptor resulted in lower sludge yield (0.28 kg VSS/kg COD) compared to nitrate (0.32 kg VSS/kg COD), while maintaining high nutrient removal.

Conclusions:

• The combined mUCT-MBR system effectively removes COD, TN, and TP.
• Using nitrite as the primary electron acceptor enhances denitrifying phosphorus removal and reduces sludge production.
• Denitrifying phosphorus-accumulating organisms play a dominant role (>80%) in phosphorus removal under optimal conditions.