Schematic Representation of Activated Sludge Models

Parametric models used in simulation software for the design of wastewater treatment plants involve a number of processes and state variables that can be best represented in a matrix format (e.g. ASM1, ASM2D, ASM3, General ASDM). These models often use different symbols for identical variables and some models are becoming increasingly complex making it difficult to visualize the relationships between the various processes. A standardized notation is first proposed for the major current parametric models which is then used to draw schematic representations of these models. These schematics should constitute useful learning tools, that should facilitate comparisons between various models and provide a better appreciation of the potential and limitations of each model to ensure a better use of activated sludge models by design engineers.