A hospital requires precise control of chlorine dioxide levels in both hot and cold potable water loops to prevent Legionella and other waterborne pathogens. Effective disinfection is critical in sensitive areas like the cancer center, where patients are more vulnerable to infection.

Managing multiple water loops with different temperature conditions presents challenges in maintaining proper chlorine dioxide dosing. Hot water systems require sensors that can withstand high temperatures. The hospital also needs reliable alarm communication and future system scalability to enhance safety and control.

In one example, two separate disinfection systems were installed:

Cancer Center Hot Water Loop – A chlorine dioxide (ClO₂) generator produces a concentrated ClO₂ solution. Walchem EHE pumps, controlled by the Walchem Intuition-9 controller, adjust the pump outputs for the chlorine dioxide feed into the system. High temperature ORP and pH sensors monitor the outbound hot water, ensuring proper dosing at ~325 mV. A cooled sample loop on the return water utilizes an amperometric disinfection sensor measuring ClO₂ to prevent overdosing (>0.6 ppm).

Main Hospital Water System – Two ClO₂ sensors monitor the cold-water loops, while two ORP sensors track the hot-water loops. The Intuition-9 controller adjusts ClO₂ dosing as needed using Walchem EHE pumps. The controller also integrates discrete alarm inputs from the generator for improved monitoring

Future Enhancements – A future enhancement for both systems will be to add a ClO₂ gas analyzer, and input this to the Intuition-9 on an analog input for datalogging and alarm capabilities. The Intuition-9 is highly configurable and will allow for future expansion of sensor, analog, and digital inputs.

The new controllers communicate over the hospital network with their on-board Ethernet TCP/IP communication.

The operators at the hospital appreciate the documentation of system operation provided by the Inuition-9 controller, and the peace of mind knowing that operation is normal unless they’ve received an alarm notification.