Using pH as a single indicator for evaluating/controlling nitritation systems under influence of major operational...

Area of Science:

• Environmental Microbiology
• Water Treatment Engineering
• Biochemical Engineering

Background:

• Nitritation is a crucial step in biological nitrogen removal.
• Controlling nitritation performance is complex due to interacting operational parameters.
• pH monitoring offers a potential single-indicator solution for system evaluation.

Purpose of the Study:

• To investigate the efficacy of pH as a sole indicator for nitritation system performance.
• To identify optimal operational conditions for nitritation under varying parameters.
• To develop process control schemes using pH for efficient ammonium removal.

Main Methods:

• Conducted fifteen batch tests to evaluate nitritation performance.
• Manipulated key operational parameters: carbon to nitrogen (C/N) ratio, temperature, and sludge/water ratio.
• Utilized pH as the primary indicator for system assessment.

Main Results:

• Significant interactions were observed between operational parameters and pH in the nitritation system.
• An optimal C/N ratio of 2.0 was identified for efficient ammonium removal.
• Fastest reaction times (150 min) were achieved at 20°C with C/N = 0 and a sludge/water ratio of 1:1.
• Adjusting C/N ratio to near zero at 10°C, with weakened heterotrophic bacteria and sufficient biomass, proved effective.
• C/N ratio of 4.0 and sludge/water ratio of 1:3 were suitable for low-temperature conditions and organic matter impact.

Conclusions:

• pH can serve as a reliable single indicator for evaluating and controlling nitritation systems.
• Optimal operational schemes can be proposed to mitigate negative impacts of parameter fluctuations.
• The findings provide insights into optimizing nitritation processes for enhanced nitrogen removal.