Process improvement and energy saving in a full scale wastewater treatment plant: Air supply regulation by a fuzzy logic system

Achieving good performance in air supply control is an important goal in the management of wastewater treatment plants, whose highly nonlinear behaviour makes the application of conventional control techniques problematic. This paper presents the development and experimentation of a fuzzy logic system for air supply regulation in a full scale municipal wastewater treatment plant. The system is composed of two main modules, one devoted to continuously adjusting the DO set point on the basis of the current effluent NH4+-N concentration (on-line measurement), and the other devoted to achieve the DO set point by controlling air supply devices. The experiment was carried out on the plant for about one year, leading to significant advantages in terms of both process stability and energy saving.