Putting Operators in Control – A Straightforward Approach to BNR Clarifier Operation

Successful operation of any activated sludge process depends on understanding the capacity of secondary clarifiers. As biological treatment facilities are operated to achieve biological nutrient removal (BNR), a careful balance must be made between reactor and secondary clarifier capacity to achieve the various treatment goals. This paper presents an approach to assist operators in determining the capacity of activated sludge secondary clarifiers using a straightforward graphical approach based on state point analysis. Analysis of performance at two facilities in Connecticut are presented documenting the validity of the graphical approach.