Innovative Kuntze analyzer resolves disinfectant feed control challenges in a northwest ground drinking water system

Background information

A public ground drinking water system (DWS) located in the Pacific Northwest serves about 15,387 connections. The spring sources are used all year, while some of their wells are typically used in spring and summer to meet higher drinking water demands. The DWS treats the spring water with chlorine gas and for the seasonal-operated wells either liquid or solid chlorine systems are used. Benefits of the solid disinfectant system is safe means of handling, decreased risk of chemical leakage, and its reduced packaging waste volume.

Challenge

Well #33 of the DWS had an old chlorine tablet feeder, which was replaced by Correct Equipment – an integrated engineering company – in spring 2017. The well is used from May through September and has a constant flow rate of about 180 GPM. The goal was to maintain a free chlorine residual between 0.4 and 0.7 ppm. The operators manually measured the chlorine residual directly after the disinfectant feed-point and further downstream in the distribution system a few times per day on each work week (on average approximately 11 measurements per week).

Each measurement included a manual DPD test (which takes less than five minutes) and about 25 minutes of driving time to the sample location, translating to about 5.5 operator hours per week. A few months after the start-up of the chemical feeding system the operators had to shut down the equipment since the target residual range could not be met consistently. The well was not used in 2018 due to the tablet feeder issues and started up again in 2019. Due to the re-occurrence of the tablet feeder issues the DWS considered replacing the tablet feeder with an $8,000 liquid chlorine feeding system.

Results

Well #33 has been operating with little difficulty for over eight months. The Krypton® Multi system has consistently maintained a free chlorine residual within the target range of 0.4 to 0.6 ppm.

The operator workload for manual DPD testing was reduced by 55 % saving three operator hours per week.

Kuntze Solution

Correct Equipment suggested the installation of a Kuntze Krypton® Multi analyzer to continuously measure and control the disinfectant residual. The DWS installed the analyzer in the beginning of 2020, which controls the speed signal of the chlorinator. The analyzer was also connected to Kuntze’s Cloud Connect® via a Kuntze Gateway, enabling the DWS to remotely monitor the residual and be notified if the chlorine residual approached the out of compliance (OOC) range. Their Krypton® Multi system also featured Kuntze’s ASR® Automatic Sensor Cleaning technology which prevented the sensor from fouling. For compliance reporting reasons, the operators still had to take one manual reference measurement test in the distribution system per day.

Conclusion

The Kuntze Krypton® Multi system reliably controls the disinfectant residual, enabling the DWS to use Well #33 and to continue using Correct Equipment’s preferred chlorine tablet system.

Installing a Kuntze analyzer reduced the time spent on manual DPD field tests by 55 % saving 66 operator hours per season (May through September).
The labor savings can now be invested into other critical operational service tasks. Kuntze’s Cloud Connect® monitoring alert system provides the DWS a reliable way to maintain a consistent residual. Based on this very positive experience, the DWS decided to replace the other 3 chlorine analyzers on-site with Kuntze systems.