OPTIMAL-CONTROL OF THE ACTIVATED-SLUDGE PROCESS

This paper describes an application of modern optimal control theory techniques in the regulation of the activated sludge process. The process is simulated using multicomponent biological reactor and dynamical thickening models. The control problem is formulated with recycle and wastage rates as control variables and is characterized by high dimensionality and system model nonlinearity. The solution is obtained by a Newton-type successive approximations control method. In the case study, this approach is compared with (1) the commonly proposed recycle ratio control strategy and (2) a constant recycle and wastage rate stategy. Wastage regulation is shown to be a much more effective control input than recycle for reducing effluent organic variability. The control framework proposed can be extended to include other regulation schemes and account for process and input uncertainties. © 1990.