State-of-the-Art Medical Center Achieves Consistent and Reliable Secondary Disinfection

State-of-the-Art Medical Center Achieves Consistent and Reliable Secondary Disinfection
When a Washington state-of-the-art medical center opened in 2011, it’s advanced environmentally friendly design earned it LEED Silver certification. The campus values patient safety above all, focusing on high quality care and sterilization techniques. When the reliability and consistency of the chlorine dioxide delivery for secondary disinfection become unreliable and required frequent maintenance, the facilities engineering team pursued an alternative solution to ensure uninterrupted campus safety.

Building acquired legionellosis is the most common vector for developing an infection. Secondary disinfection of a building water system involves feeding a supplemental disinfectant concurrently with the treated potable water from a municipal supplier. Secondary disinfection can be a critical measure in preventing the spread of this bacterial infection.

Consistent with its mantra of patient safety, secondary disinfection of its hot water loop for the entire campus was employed from the beginning. It began operations with a competitive automated secondary disinfection system.

Unfortunately, there were consistent problems with reliability and consistency of chlorine dioxide delivery, and the need for frequent manual attention. These problems included tubing leaks, loss of chemical pump prime, failed cartridges, power issues, and the inability to calibrate the sensor probe. Within two years of startup, the facilities engineering team decided they needed to pursue an alternative solution.

U.S. Water Solution
After discussions with U.S. Water personnel, the facility’s engineering team chose U.S. Water’s ChlorOpt EC3 electrochemical generation system to replace the existing ClO2 system. The ChlorOpt EC3 system would provide a safe, efficient, and more cost-effective way to apply CIO2. Chlorine dioxide is generated utilizing a single precursor chemical, eliminating acid or chlorine typically required for generation.

Unlike the predecessor system, the ChlorOpt EC3 system does not utilize cartridges/cassettes for generation, and therefore their frequent and costly replacement was eliminated.

The ChlorOpt EC3 system is equipped with U.S. Water’s Wireless Gateway which enables the continuous and seamless flow of critical measurement and control data to U.S. Water ReportsTM, the cloud-based data management , analytics and reporting platform of U.S. Water.

The automation was complimented with a manual testing protocol. Hospital personnel test for chlorine dioxide concentration once per week at multiple locations throughout the system during feed cycles. This ensures that the desired residuals are being attained. Manual testing is performed daily for chlorite concentrations as well, to ensure the U.S. EPA requirement of 1.0 ppm is not exceeded.

U.S. Water technicians also perform regular onsite service, which includes manual testing for chlorine dioxide and chlorite. Consumables, such as reverse osmosis membranes and chemicals, are also incorporated into the maintenance schedule.

A complete suite of testing is performed via an external CDC ELITE certified third party laboratory. Sampling from ten sample points is performed. The sample points include some that are consistently tested, as well as other rotating sites.

Proven Results
The ChlorOpt EC3‘s installation was clean, neat and clutter free, with a minimal footprint versus the previous system.

As of this writing, for nearly two and a half years since installation, the ChlorOpt EC3 system has delivered reliable, effective and efficient secondary disinfection.

A dosing scheme was developed and fine-tuned; such that the targeted 0.2-0.3 ppm maximum residual chlorine dioxide concentration was not exceeded, and the measure chlorite concentrate was maintained below the U.S. EPA limit of 1.0 ppm.

Several studies have been conducted to affirm the integrity of biological control. These included sampling and testing with methods such as adenosine triphosphate (ATP), bio dip slides, and specific cultures for heterotrophic and Legionella bacteria. All testing has proved excellent control over harmful bacteria. Specifically, regular tests for Legionella are negative.

The use of ClO2 is extremely effective in minimizing biofilm on pipe surfaces. Biofilm is considered a leading precursor for Legionella growth. The evidence of biofilm removal was visible as particulate discharges from the hot water system.

Connectivity with U.S. Water Reports enables personnel to have remote visibility to monitor system performance. This ensures that that the key requirements of the disinfection application are being met, and alerts personnel if any corrective actions need to be taken.

Excellent and regular communication between the center and U.S. Water has kept all stakeholders engaged and focused on delivering the expected results.