Optimized water softening systems thanks to quality-controlled regeneration

Novel water hardness monitoring
Ion exchange units with sodium chloride regeneration have been increasingly used for more than 50 years for the production of soft water. The course and dynamics of the softening process depend on the ion exchange resins used, the proper regenera¬tion processes, the removal quantities and their dynamics.
These processes do not run constantly in practice, which is why resin capacities are not exhausted in all water softening systems for reasons of variability and the lack of process monitoring. For this reason, the softening plants are traditionally regener¬ated in quantity or time. Investigations on this revealed capac¬ity reserves of 20% to 50% of the resin capacity used.
It would be desirable to constantly monitor the softening pro¬cess. The aim is to detect the desired degree of exhaustion and to perform the regeneration control of the water softening system dependent on the hardness. However, this is not possi¬ble with today’s largely traditional and known photometric measurement techniques.

Limits of conventional processes
In recent decades, the cyclic photometric measurement meth¬od has emerged as the technical standard for soft water mon¬itoring. The residual hardness is determined randomly by means of color change, the residual water hardness value determined is compared to the specified soft water limit value and the alarm is triggered when the limit value is exceeded.
With a larger number of measurements, the indicator consump¬tion and the mechanical wear of the measuring device increase, resulting in re-adjustment, cleaning and functional control with increased service costs. To avoid this, long measurement breaks with low indicator consumption and low measuring frequency are aimed for.
Regardless of this, however, aging processes occur, which lead to creeping problems that would not occur with increased mea¬surement frequency. In addition, manual control activities must be performed to verify the process-safe condition to compensate for lack of self-control.
Thus, a compromise between measurement frequency and sus¬ceptibility has to be found in order to limit operating and main¬tenance costs. However, a high level of process reliability and continuity is increasingly being sought.

Process-safe continuous soft water monitoring
By means of a novel soft water monitoring process, which was developed with the product line “Softcontrol” of the OFS GmbH, a measuring and control device with potentiometric measuring procedure for the permanent monitoring of the soft water is presented. This not only monitors the residual hardness and the measurement functionality very sensitively in cyclic circum¬stances, but also has intelligent self-monitoring.
Previous problems and obstacles of conventional measuring tech¬niques are solved, and a high reliability and economically contin¬uous measuring functionality is ensured over long periods of time.
The process principle is based on a calcium-magnesium-selec¬tive electrode, which constantly determines the difference in water hardness between hard and soft water and evaluates to a predetermined limit.
The applied differential method offers the possibility to exclude sensor drift and to monitor the sensor quality. Thus, the soft water hardness is monitored, so that a high process and control security is given. According to these possibilities not only limit value monitoring in soft water, but also optimal conditions for a quality-controlled regeneration of softening plants are prov¬en. Thus, a premature regeneration release is prevented by hardness and the soft water capacity is optimally utilized.

Effective capacity utilization
For the first time, this principle, with sensor life independent of the measuring cycles and lacking indicator means, enables continuous monitoring of water softening systems under eco¬nomically effective conditions.
Thus, according to different practical conditions, 20% to 50% fewer regeneration cycles could be achieved when switching from batch to quality-controlled operation of the water soften¬er. This reduced regeneration costs, kept the amount of soft water constant and the quality of the water high.

Conclusion
The presented measurement process provides an economical, process-safe alternative to monitoring the softening process. This ensures the full utilization of the capacity of the softening plants, so that resources are saved. So, rinse and salt water are significantly reduced and increases the amount of soft water. The device family leads to a high level of process reliability and, at the same time, ecological operation.

Christina Schellbach
c.schellbach@water-monitoring.com
+49 36602 5124 261

OFS Online Fluid Sensoric GmbH
https://www.water-monitoring.com
Heidelbergweg 9
07580 Ronneburg
Germany

OFS GmbH is a medium-sized company with decades of expertise in industrial water treatment. Our goal is the environmentally conscious handling of the resource water. Our products include process water analysis, monitoring and control systems of process water and cooling / climate water. Our requirements for operational and process reliability, economy and environmental friendliness set new standards. As a developer and plant manufacturer, we pull the strings and offer customized overall solutions.

This release was published on openPR.