Recirculating cool water systems provide excellent conditions for biological growths, including: algae, slime, bacteria, and water-borne pathogens.
Biological fouling is the unwanted accumulation of these various microorganisms within cooling systems. When microorganisms are present in the cooling water, a layer of biofilm can form on all surfaces in contact with the water. The biofilm acts as a thermal insulator and decreases heat transfer efficiency. In addition, biological fouling can cause corrosion and scaling/deposit accumulation.
The presence of pathogens in water, such as legionella bacteria, can cause serious health and safety concerns. One of the primary sources of such particles in the air is the windage, or drift, produced by the normal operation of a cooling tower. Droplets of cooling water is entrained in the airstream, and if the cooling water contains bacteria such as legionella, inhalation of the contaminated droplets can be a source of infectious disease.