The performance of a drinking-water treatment plant is determined by the control of the plant. To design the appropriate control system, a control-design methodology of five design steps is proposed, which takes the treatment process characteristics into account. For each design step, the necessary actions are defined. Using the methodology for the pellet-softening treatment step, a new control scheme for the pellet-softening treatment step has been designed and implemented in the full-scale plant. The implementation resulted in a chemical usage reduction of 15% and reduction in the maintenance effort for this treatment step. Corrective actions of operators are no longer necessary.
Keywords: control design, drinking water