Non-linear modelling and identification of a coagulant dosage system for water treatment plants

Non-linear modelling and estimation of a coagulant dosage system for water treatment plants based on Hammerstein-Wiener models is presented in this paper. Different configurations of the Hammerstein-Wiener model for the system are developed and compared with each other. The most suitable model configuration is selected and linearised at an estimated operating point. Simulation results further show that the Hammerstein-Wiener model configuration with both saturation and dead-zone as input channels and piecewise linear functions as output channels has remarkable improvement over Hammerstein, Weiner, other configurations of Hammerstein-Wiener and linear models. The proposed model is in a form that the widely used controllers in the industry could be applied to improve automatic control of coagulation process.