[Stability of the CANON Process Based on Real-Time Control Technologies]

Area of Science:

• Environmental Science
• Water Treatment Engineering
• Microbiology

Background:

• The Conventional Activated Nitrification-Nitrogen (CANON) process is crucial for removing ammonia nitrogen from wastewater.
• Optimizing the CANON process is essential for stable water quality and efficient nitrogen removal.
• Real-time control strategies are needed to enhance the stability and performance of the CANON process.

Purpose of the Study:

• To investigate the stability of the CANON process water quality under real-time control in a Sequencing Batch Reactor (SBR).
• To identify reliable control parameters for optimizing ammonia nitrogen removal efficiency and ensuring water quality stability.

Main Methods:

• Experiments were conducted in an SBR reactor with temperature controlled at 30℃±1℃ and pH maintained at 7-8.
• A real-time control strategy was formulated based on the relationship between indirect parameters and nitrogen pollutants.
• The performance of direct ammonia nitrogen sensors versus indirect parameters (pH, Dissolved Oxygen (DO), Oxidation-Reduction Potential (ORP)) was evaluated.

Main Results:

• A residual ammonia nitrogen concentration of 6 mg·L⁻¹ was identified as a viable control parameter for influent concentrations of 917-1540 mg·L⁻¹, but direct sensors proved costly and error-prone.
• Characteristic points and platforms of pH, DO, and ORP values were found to be effective automatic control parameters.
• The CANON process demonstrated long-term stable operation with an average ammonia nitrogen removal rate exceeding 99% and stable effluent quality.

Conclusions:

• Indirect parameters like pH, DO, and ORP are reliable and cost-effective for real-time control of the CANON process in SBRs.
• Utilizing these indirect parameters ensures stable operation, high ammonia nitrogen removal efficiency (>99%), and consistent effluent quality.
• This study provides a robust control strategy for optimizing wastewater treatment through the CANON process.