Measuring and control concepts are a cost-saving and environmental friendlier alternative to the extension of reactor volume and are an excellent solution to adapt the plant to different loadings. A draw-back is that a controlled plant is driven to the limits of its capacity and subsequently equipment failures (sensors and actuators), unexpected changes in the influent or environmental conditions can cause severe effluent limit violations if unsuitable control concepts are used. Thus, the aim of Lluis' project was to design a control system in a way that it is able to deal with different loading situations as well as handling sensor or actuator failures. This was linked to several modelEAU projects (monEAU, NEPTUNE, SRO) and also with the BENCHMARK IWA Task Group.