"Report date February 1972." Includes bibliographical references (pages 89-93). United States Environmental Protection Agency Contract No. Contract Number: 14-12-194.

The final clarifier in the activated sludge process performs a vital role in secondary waste treatment systems. The purpose of the project was to develop a mathematical model to predict the solids concentration of both the underflow and overflow of a final clarifier as a function of the mixed liquor characteristics. It was concluded that neither the effluent suspended solids nor the return sludge concentration can be estimated with good accuracy from those parameters which are normally available to the design engineer. Recommendations for future work which would enable a more realistic approach to the preliminary design of final clarifiers are made.