Water Disinfection Case Study: Cooling Water Treatment

Professional treatment of cooling water in an evaporative cooler

• What is being treated? Evaporative cooling tower on the roof of a hospital
• With which products? Sanosil Super 25, Corfit CT Protect B
• Using which method? Shock disinfection / cleaning of the cooling tower, routine treatment with biocide, corrosion inhibitor, and hardness stabilizer

Description of the situation:

A clinic operates two evaporative cooling towers on the roof of the building. The newly assigned facility management company responsible for the care of the cooling system has noticed that maintenance and water treatment have not been optimally performed in the past. Therefore, the clinic management is concerned that Legionella could potentially form in the warm water.

Specifics:

The clients are seeking the most effective treatment possible while also taking environmental considerations into account. Chlorine or bromine biocides are not to be used due to AOX (Adsorbable Organic Halogen) formation concerns.

Implementation

In preparation for cleaning, the cooling systems are treated with 100 ml of Biodispersant and 1-2 liters of Sanosil Super 25 per cubic meter of basin water and operated for some time. This process dissolves dirt, biofilms, and algae. (Descaling with Corfit Bright can be omitted as there are practically no visible mineral deposits.)

Subsequently, the basin is drained with the dirty water, and the cooling tower is manually cleaned. The basin is then refilled, and a dosing pump is installed for Super 25 and Corfit B (combined hardness stabilizer, corrosion inhibitor, and dispersant).

Results

After the commissioning phase, fine adjustments are made to the dosages, followed by transitioning to normal operation with approximately 3.5 times concentration. Periodic checks of the cooling tower show no deposits or corrosion, and the system operates flawlessly. Legionella and other microbial counts are well below prescribed limits.