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Parameterestimation in oxidation ditch modelling

The oxidation ditch is becoming increasingly popular in the United Kingdom for comparatively low-load domestic waste treatment situations. It has found widespread use for larger-scale waste treatment in Europe, especially in Holland. The original oxidation ditch concept is over 20 years old, and much research work has been carried out on the sludge characteristics and chemical processes. As a result of ever-increasing operational costs and more stringent effluent quality standards, the need has now arisen for a detailed study of the dynamics of the oxidation ditch process. This paper forms part of an overall model identification study and intends to examine the possibility of on-line parameter estimation using the Extended Kalman Filter. The first part of the paper develops a non- linear, conceptual, dynamic model of dissolved oxygen (DO)/biological oxygen demand (BOD) interaction in the oxidation ditch. The model is employed together with an arbitrary set of parameters, in the synthesis of a series of noise-corrupted process data. The second part of the paper gives the Filter equations and the third part presents the results of the parameter estimation study.