The Basics of Automated Activated Sludge Process Control: Keep It Simple

Activated sludge is a versatile process that can be used to provide different levels of wastewater treatment from BOD-only removal to full biological nutrient removal (BNR). No matter what level of treatment is required, the common requirements for good plant performance are dissolved oxygen (DO) and solids wasting control. Once the DO concentration and solids wasting processes are properly controlled, the activated sludge process will efficiently remove BOD, oxidize ammonia and, in advanced treatment systems, denitrify and remove phosphorus. However, if there is insufficient DO or if the solids are over wasted, the process will fail. These are the basics of activated sludge process control.This paper discusses the reasons for considering automated process control and the elements that must be considered in both DO and solids wasting control systems.