Optimal Activated Sludge Design under Uncertainty

by Arthur R. Tarrer, Asst.Prof.; Dept. of Civ. Engrg., Auburn Univ., Auburn, Ala.,
Lowell B. Koppel, Prof. and Head; School of Chemical Engrg., Purdue Univ., West Lafayette, Ind.,
Henry C. Lim, Prof.; School of Chemical Engrg., Purdue Univ., West Lafayette, Ind.,
C. P. Leslie Grady, Jr., Visiting Scholar; Dept. of Chemical Engrg., Univ. of Texas, Austin, Tex., and Assoc. Prof., School of Civ. Engrg., Purdue Univ., West Lafayette, Ind.,

Serial Information: Journal of the Environmental Engineering Division, 1976, Vol. 102, Issue 3, Pg. 657-673

Document Type: Journal Paper


A mathematical model of the liquid process train (primary settler, aeration basin, final settler, chlorination) of the activated sludge process was developed and used to obtain the optimum design required to meet specified criteria for effluent soluble organics and suspended solids concentrations with a desired degree of confidence. Provisions were made for incorporating the uncertainty associated with experimentally determined parameters. The final settler model included both clarification and thickening functions and it was found that the clarification term exerted a strong effect upon the final design. Liquid-solid separation parameters were found to be as important as biological kinetic parameters in determining the optimum design. Treatment cost was found to be relatively insensitive to the mean cell residence time or the suspended solids removal efficiency, although those items exerted significant effects upon the sizes of the individual unit operations. Considerable conservatism could be incorporated into optimum designs with relatively small cost penalties.

Subject Headings: Parameters (statistics) | Activated sludge | Uncertainty principles | Turbidity | Mathematical models | Hydrologic models | Aeration | Basins

Services: Buy this book/Buy this article


Return to search