Comprehensive Model of Activated Sludge Wastewater Treatment System

Abstract

Comprehensive models of wastewater treatment systems are evolving and offer potential as tools for aiding engineers in developing cost‐effective designs. These tools can be used for examining tradeoffs among unit processes, as well as issues such as reliability, safety factors, energy efficiency, and regional wastewater management. This paper presents a comprehensive model of a typical activated sludge wastewater treatment system operated at steady state. It includes both the liquid and solids portions of the treatment system and recycle streams. The model can be used in either an analysis mode or an optimization model. Three optimization algorithms have been shown to be effective. A complete formulation is given for one of them, the generalized reduced gradient (GRG) algorithm. Two example solutions are shown; one was obtained using an analysis program and one using GRG. Discussions of the optimization methods and of the potential uses of the model are provided in companion works.