Dynamic model of secondary process of urban wastewater treatment plants

Summary

This paper presents the methodology for obtaining equations which describe the secondary treatment of urban wastewater treatment plants.

The kinetics of the biodegradation reaction are shown, and a proposal is made to include the sludge age in the specific growth rate, in order to generalize from the classic process of activated sludge to that of extended aeration.

The application of a mass balance to the aerobic reactor is shown, in order to obtain equations which describe its behavior.

We will introduce a working hypothesis of the sludge settling mechanism to determine volumes of the clarification and sedimentation zones of the final clarifier, in order to obtain equations describing it.

A graphic demonstration is provided with the results of activated sludge process simulation using the mathematical model presented here.

Key words:

• Modeling
• Wastewater
• Activated Sludge
• Secondary Treatment
• Aerobic Reactor
• Aerobic Digester
• Mass Balance
• Secondary Decanter
• Final Clarifier