A H∞H∞ control for optimizing the advanced oxidation processes—Case of a catalytic ozonation reactor

• The closed-loop control for water treatment by AOP gives significant reagent savings.
• We address the problem of disturbance attenuation through the H∞H∞ synthesis.
• The set-point tracking is achieved by PI controllers.
• A closed-loop stability analysis with respect to time delays is developed.
• All developments are applied to a catalytic ozonation pilot.

In wastewater treatment, advanced oxidation processes are largely accepted as efficient technologies. Unfortunately, in general, these approaches present a high operating cost due to an open-loop implementation, i.e.   the inlet reagent is introduced in excess in order to respect discharge standards. Therefore a mixture between automatic control techniques and chemical engineering expertise should significantly improve and expand their industrial applications via closed-loop implementations. More precisely, the present paper deals with a catalytic ozonation reactor where the main objective is to reduce the oxygen consumption by minimizing the ozone overproduction. For this end, a H∞H∞ control strategy is used in order to obtain a significant abatement of the pollutant, and by the way illustrates the gain one can expect when applying such techniques to this kind of process.