The Determination of SRT in the Design of Step Aeration by Using Particle Swarm Optimization

The determination of the solid retention time(SRT) is key to successfully design the activated sludge,which was usually estimated based on experiences in the past.This paper presents an unconstrained optimization model with one single unknown element to determine the SRT of step aeration and employs particle swarm optimization(PSO) algorithm to solve this optimal problem.Calculating result of the example shows that the PSO algorithm can solve the SRT accurately and fast,providing a theoretical foundation for designing sewage treatment plants.