Automatic control strategy for step feed anoxic/aerobic biological nitrogen removal process.

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Process Control

Background:

• Effective wastewater treatment relies on precise control of activated sludge process parameters.
• Sludge age and mixed liquor suspended solids (MLSS) are critical for optimizing treatment efficiency.
• Variations in influent characteristics can challenge process stability.

Purpose of the Study:

• To develop a nonlinear dynamic model for a step-feed activated sludge process.
• To implement a control strategy for sludge age and MLSS in the final aerator.
• To evaluate the model's performance under varying influent conditions.

Main Methods:

• Development of a nonlinear dynamic model for the step-feed activated sludge process.
• Control of sludge age by adjusting sludge recycle flow rate.
• Control of MLSS concentration by adjusting sludge wastage flow rate.
• Simulation of the process under dynamic influent characteristics.

Main Results:

• The developed model maintained a stable sludge age of approximately 16 days despite influent variations.
• Mixed liquor suspended solids in the final aerator were consistently regulated at the target of 2500 g/m³.
• The control strategy proved effective in maintaining desired operational parameters.

Conclusions:

• The nonlinear dynamic model provides robust control for step-feed activated sludge systems.
• The proposed control approach ensures stable wastewater treatment performance.
• This model is valuable for optimizing and managing activated sludge processes.