A combined transfer-function noise model to predict the dynamic behavior of a full-scale primary sedimentation tank

Studying how and to what extent effluent TSS and COD are related to influent TSS, COD, and flow in a primary sedimentation process is the objective of this paper. The analysis is based on data collected hourly over two periods of sampling, each lasted 1 week at an Edmonton, Alberta sewage treatment plant. In order to establish a dynamic model for the system, the methodology of Box and Jenkins (Time series Analysis: Forecasting and Control, Holden-Day, Oakland, CA, 1976) was utilized. With this approach, stochastic and transfer-function components can be combined to form a dynamic model and the relative importance of these two components can be quantitatively assessed. The models were able to explain the data very well. Using the models as parts of a real-time control scheme was also discussed.