Adaptive predictive expert (ADEX) control: application to wastewater treatment plants

This paper presents the application of a new adaptive predictive expert (ADEX) control methodology to the biological phase of a residual water treatment plant. The ADEX methodology adds an expert block into the operation of previously known adaptive predictive control systems. This expert block, based on rules and in the evolution of the process variables, determines and/or modifies the operations of the driver block, control block and adaptive feedback mechanism of the previous art, in order to improve the performance, robustness and stability of the overall control system. The biological process has an inherent multivariable, time-varying and nonlinear dynamic nature, and is submitted to stochastic and discontinuous perturbations, such as significant changes in the flow rate of residual water and its load of dirtiness. The integration of ADEX controllers within a control and optimization strategy, implemented in the local PLC, allowed the new control system to achieve a precise control of the oxygen levels and to optimize the process operation.