Sample interview questions: Can you explain the process of inspecting plumbing systems for the prevention of Legionella growth in cooling towers?
Sample answer:
Inspection Process for Legionella Prevention in Cooling Towers
1. Visual Inspection:
- Examine the cooling tower for visible signs of scale, biofilm, or algae growth – breeding grounds for Legionella.
- Inspect the water distribution system for leaks or cracks that could introduce contaminants.
- Check the drift eliminators for functionality and cleanliness to prevent water droplets containing Legionella from escaping.
2. Water Testing:
- Collect water samples from the cooling tower basin, distribution system, and blowdown line.
- Test for Legionella pneumophila using accredited laboratory methods (e.g., culture, PCR).
- Monitor total heterotrophic bacteria (THB) and heterotrophic plate count (HPC) as indicators of overall microbial growth.
3. Temperature Monitoring:
- Measure water temperature at various points in the cooling tower system, including the basin, cold water supply, and blowdown.
- Ensure temperatures are maintained within acceptable ranges (typically below 25°C or 77°F) to inhibit Legionella growth.
4. Chemical Treatment Evaluation:
- Review the chemical treatment plan and its implementation.
- Ensure proper d… Read full answer
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