ANALYSIS OF ENDOGENOUS PROCESS BEHAVIOR IN ACTIVATED-SLUDGE

In this article, an autonomous four-compartment model that describes t he endogenous respiration in an aerobic biodegradation process is prop osed and analyzed theoretically. First, the multi-time scale of the sy stem's behavior, to be taken into account in subsequent analyses, is e mphasized. Then, an identifiability and observability study, given mea surements of MLVSS (mixed liquor volatile suspended solids) and respir ation rate, is performed for use under practical circumstances, such a s in state and parameter estimation. It appears that the process is ob servable, but not fully identifiable. Hence, for the identification of some of the model parameters, additional measurements or experiments, also indicated here, have to be performed. Furthermore, it is shown t hat, under quasi-steady state conditions which, in general, appear sho rtly after initialization of an endogenous respiration experiment, the model can be reduced significantly. Finally, results of parameter est imation from available data are presented and discussed. (C) 1998 John Wiley & Sons, Inc.