RESEARCHERS with the University of Pittsburgh claim non-chemical water treatments may not kill the bacteria in large building cooling systems.
Non-chemical treatment systems are used as more environmentally-friendly alternatives to chemicals like chlorine for cleaning the water-based air-conditioning systems found in many large buildings.
The American Society of Heating, Refrigerating, and Air-Conditioning Engineers funded a two-year study by University of Pittsburgh researchers into five devices such devices.
The results showed the same rate of bacterial growth in these systems as untreated water. This could indicate the treatments are ineffective, allowing bacteria to flourish in the cooling systems of hospitals, commercial offices, and other water-cooled buildings.
According to the researchers, equipment operators, building owners and engineers should monitor systems that rely on Non-Chemical Treatment Devices to control microorganisms.
One possible measure is to add chemical treatment as needed to prevent a potential health hazard.
The researchers constructed two scale models of typical cooling towers. One model remained untreated while the other was treated with five commercially available NCDs installed according to the manufacturers’ guidelines. Each device was tested for four weeks.
The NCDs tested included pulsed electric-field devices, electrostatic devices, ultrasonic devices, hydrodynamic cavitation devices, and a magnetic device.