METHOD FOR OPERATING A WATER TREATMENT PLANT WITH CORRECTION OF CHARACTERISTIC CALIBRATION CURVES

摘要

The invention relates to a method for operating a water treatment plant (31), having a softening device (35), which comprises in particular an ion exchanger resin (38), a conductivity sensor (34), an automatically adjustable mixing unit for mixing a mixing water flow V(t)verschnitt composed of a first, softened partial flow V(t)teil1weich and a second, partial flow V(t)teil2roh conducting untreated water, the method comprising the following steps: determining the electrical conductivity (4) of the untreated, soft or mixed water by means of the conductivity sensor (34) and, based thereon, determining the overall hardness GLF of the untreated water by means of one or more characteristic calibration curves (K) stored in an electronic controller (43), controlling the adjustment position of the mixing unit (5) by means of the electronic controller (43) taking the determined overall hardness GLF of the untreated water into consideration so that the water hardness in the mixed water flow V(t)verschnitt is set to a predetermined target value (SW), wherein said method is characterized in that a mixed water hardness VNK is determined non-conductometrically (6) and compared (8) to the target value (SW), and one or more characteristic calibration lines (K) for determining the total hardness GLF of the untreated water are modified (10) if the deviation of the mixed water hardness VNK determined non-conductometrically from the target value (SW) exceeds a limit value. The invention makes it possible for the mixing unit to be automatically controlled with high precision and in a cost-effective manner with a variety of untreated water compositions.