Geisinger pioneers legionella control
Staff -- Plant Engineering, 4/1/2003
In a groundbreaking effort, the Facilities Operations Group of Geisinger Health System, Danville, PA, developed a system to eliminate legionella bacteria from its domestic water supply. Their solution was the first successful system implemented at a hospital in the U.S. Test results conclusively prove that the organism is controlled and the safety of patients and staff is enhanced.
The main campus of the health system is home to a large medical center including a level one regional trauma center on a 460-acre site with 2 million sq ft of buildings and a 550,000-gal reservoir supplied by a well, a spring, and municipal water.
Statistics show that 50% of healthcare facilities harbor the dangerous legionella organism in their domestic water systems. Legionnaires disease is a type of pneumonia that is fatal if not diagnosed and treated early. A susceptible host contracts the disease by inhaling aerosolized water droplets containing the organism.
Tests using a heat-and-flush procedure provided only temporary improvements by killing legionella bacteria on the surface of the biofilm in the piping network. Bacteria deeper in the biofilm were not affected and re-emerged. Finally, a cure was found by injecting chlorine dioxide (ClO2) into the water system and implementing a number of other changes:
- Dead legs and distal sites in the piping system were removed
- Old cross-flow cooling towers with 10-12-deg approaches were replaced with 5-deg approach counterflow towers with no sumps
- Compressed air system has been converted to an entirely dry system by installing scroll compressors, variable-frequency-drive oil-free compressors, and heat-of-compression dryers
- Regular flushing of hot-water storage tanks.
By combining research, problem analysis, system engineering, and improved practices, the problem of legionella bacteria has been eliminated.
