Optimization of partial nitritation in a continuous flow internal loop airlift reactor.

Area of Science:

• Environmental Engineering
• Biotechnology
• Wastewater Treatment

Background:

• Partial nitritation (PN) is crucial for nitrogen removal in wastewater treatment.
• Optimizing PN processes enhances efficiency and reduces operational costs.
• Continuous flow internal loop airlift reactors offer advantages for PN.

Purpose of the Study:

• To optimize the partial nitritation (PN) process in a continuous flow internal loop airlift reactor.
• To determine the optimal influent ammonium (NH4(+)-Ninf), dissolved oxygen (DO), and alkalinity/ammonium ratio (Alk/NH4(+)-N).
• To maximize effluent nitrite to ammonium molar ratio and nitrite accumulation ratio.

Main Methods:

• Response Surface Method (RSM) was employed for process optimization.
• Reduced cubic and quadratic models were developed to predict optimal conditions.
• Confirmation trials were conducted to validate the model predictions.

Main Results:

• Optimal DO: 1.1-2.1 mg L(-1)
• Optimal Alk/NH4(+)-N ratio: 3.30-5.69
• Optimal NH4(+)-Ninf: 608-1039 mg L(-1)
• Bicarbonate identified as the superior alkalinity source.

Conclusions:

• The study successfully identified optimal operating parameters for PN in airlift reactors.
• RSM is an effective tool for optimizing complex biological wastewater treatment processes.
• Bicarbonate is recommended as the preferred alkalinity source for enhanced PN performance.