By: Steve Chewning – Vice President of Field Operations – Southeastern Laboratories, Inc.
A major medical facility in the Southeast US recently implemented a ProMossTM trial on their 1,300-ton HVAC cooling tower system. The system had been operating under a conventional chemical treatment program utilizing an inhibitor product and two micro biocides. Conditions at the start of the trial are summarized below.
The system had higher than expected bacteria levels with correspondingly high ATP values. Water clarity was poor and there were significant iron and copper levels present indicative of active corrosion occurring in the system.
ProMossTM was introduced to the system using cages dropped into the cooling tower sump. All chemical feed was discontinued. After two weeks, the following conditions were observed.
The ProMossTM program had affected the following changes on the system:
- Total bacteria counts dropped from 107 to 102 CFU/ml
- ATP dropped from 2,610 to 126 RLU’s reflective of the bacteria count drop
- Water clarity (turbidity) improved significantly dropping from 28 to 2 NTU’s
- Iron levels were reduced from 1.69 ppm to 0.02 ppm
- Copper levels were reduced from 0.42 to 0.29 ppm
Throughout the 3-month trial total bacteria counts remained in the 102 to 103 range with ATP values averaging 182 RLU’s. This was impressive considering the trial was conducted during the high load Summer season, which places the highest demand on microbiological control. Iron and copper levels averaged 0.09 ppm and 0.21 ppm respectively during the trial.
This facility is currently considering switching all of their cooling tower systems to ProMossTM. Southeastern Labs has recommended supplementary disinfection generators as well that utilize UV lamps to meet accepted Legionella guidelines, which will result in removal of all cooling tower treatment chemicals from the site.