Analysis of endogenous process behaviour

In this paper an autonomous four-compartment model that describes the endogenous respiration in a aerobe biodegradation process is proposed and analysed theoretically. First the multi-time scale of the system's behaviour, to be taken into account in subsequent analyses, is emphasized. Then, an identifiability study, given measurements of MLVSS (mixed liquor volatile suspended solids) and respiration rate, is performed for use under practical circumstances such as in parameter estimation. It appears that the process is not fully identifiable. Hence, for the identification of some of the model parameters additional measurements or experiments, also indicated in the paper, have to be performed. Furthermore, it is shown that, under quasi-steady state conditions which in general appear shortly after initialization of an endogenous respiration experiment, the model can be reduced significantly.