Resumen de Contribución al modelado e implementación de un control avanzado para un proceso de cloración de una estación de tratamiento de agua potable
The effective disinfection in chlorination tanks of drinking water treatment plants depends on many factors that must be taken into account when designing a suitable control system. The chemical characteristics of the water to be treated, the possible flow disturbances or the contact time of the chlorine with the outgoing water must be taken into account in order to establish a control strategy that contemplates adaptation to the different possible scenarios. An excessive dosage of chlorine, or on the other hand a deficit in the dose, may lead to a legal failure to comply with the existing regulations that establish obligatory limit values. Likewise, an overdose generates an unnecessary expenditure of chlorine and, as a collateral effect, problems due to an increase in the maximum values allowed for by-products such as trihalomethanes. The contribution of the present work regarding chlorination in drinking water treatment tanks is divided into two areas: simulation and control. The studies and field work have been carried out on one of the largest drinking water treatment plants in southern Europe. The design and implementation of a simulator has made it possible to reproduce the behaviour of the system to test the proposed controller without the need to interfere in the production process, thus avoiding possible effects on the supply. The control implemented at the Plant is based on a control advance that compensates the disturbance of ammonium and other compounds and a feedback with planned gains depending on the flow rate and the temperature and origin of the water to be treated. The two control blocks (feedforward and feedback) are supervised by a diffuse system that, depending on the characteristics of the water to be treated, combines a control feedforward with a gains planning on a PI control.The simulation and experimental results obtained have been validated with real plant data from the Supervision System database. The control presented in this work has been integrated into the current Plant Control System. The results obtained, apart from being satisfactory, have allowed the Plant Control Room operator to move from the role of Process Control to that of Supervision of the Chlorination Process.
