Activated sludge systems are wastewater treatment systems that produce an activated mass of microorganisms (also known as sludge) capable of aerobically degrading waste.

The purpose of this document is to help wastewater professionals acquire a greater knowledge of the activated sludge process, calculate performance metrics, and improve the efficiency and ease of their operations. It can serve as both informational and as a reference for future use.

This guide includes

  • A condensed summary of the different treatment systems and operational parameters
  • A list of commonly-used abbreviations and terms with definitions
  • A list of formulas used to calculate different wastewater metrics