Validation and implementation of model based control strategies at an industrial wastewater treatment plant

In this paper, the practical implementation and validation of advanced cont rol strategies, designed using model based techniques, at an industrial was tewater treatment plant is demonstrated. The plant under study is treating the wastewater of a large pharmaceutical production facility. The process c haracteristics of the wastewater treatment were quantified by means of trac er tests, intensive measurement campaigns and the use of on-line sensors. I n parallel, a dynamical model of the complete wastewater plant was develope d according to the specific kinetic characteristics of the sludge and the h ighly varying composition of the industrial wastewater. Based on real-time data and dynamic models, control strategies for the equalisation system, th e polymer dosing and phosphorus addition were established. The control stra tegies are being integrated in the existing SCADA system combining traditio nal PLC technology with robust PC based control calculations. The use of in telligent control in wastewater treatment offers a wide spectrum of possibi lities to upgrade existing plants, to increase the capacity of the plant an d to eliminate peaks. This can result in a more stable and secure overall p erformance and, finally, in cost savings. The use of on-line sensors has a potential not only for monitoring concentrations, but also for manipulating flows and concentrations. This way the performance of the plant can be sec ured.