Optimization of activated sludge reactor configuration: kinetic considerations

Area of Science:

• Environmental Engineering
• Biochemical Engineering
• Wastewater Treatment

Background:

• Effective design of staged activated sludge systems necessitates accurate biomass requirement calculations.
• Biomass requirements are influenced by system kinetics and specific treatment objectives.

Purpose of the Study:

• To develop a procedure for determining the optimal reactor configuration in staged activated sludge systems.
• To analyze the impact of various operational parameters on biomass requirements and system design.

Main Methods:

• Development of a procedure to determine optimum reactor configuration for activated sludge systems.
• Utilizing dimensionless plots to visualize minimum biomass requirements and optimal tank sizing for series configurations.
• Analysis across a range of influent/effluent substrate concentrations, half-saturation coefficients, and number of tanks.

Main Results:

• Dimensionless plots illustrate the minimum biomass requirement for series configurations compared to a single continuous stirred-tank reactor (CSTR).
• The results highlight optimal relative sizing of tanks within a series system.
• Identified that three tanks in series generally offers the best performance.

Conclusions:

• The developed procedure and plots are directly applicable to the design of staged activated sludge systems.
• Increased influent substrate concentrations and stricter effluent requirements enhance the advantages of staging.
• Optimal, non-equal tank sizing significantly improves system efficiency over equal-sized tanks.