Cooling towers are widely used in H.V.A.C. and Industry. The towers will normally employ evaporation of water, and heat exchange the building HVAC circulating water, to cool water. The evaporation results in the concentration of dissolved solids in the cooling tower recirculation water. Scale, principally in the form of calcium carbonate, can build up, thereby reducing the rates of heat transfer and hence the efficiency of the tower. The water is also suitable for the growth of biological contaminants such as bacteria and algae. Biofouling organisms, using organic nutrients collected by scale deposits, attack system surfaces with corrosive acids to further increase dissolved particulate contamination. Conventional chemical treatment, particularly since chromates were banned by E.P.A., in practice, does not control scale, corrosion or microbiological contamination, and produces the potential liability of toxic discharge water into the environment, and handling barrels of toxic chemicals.
U.S. Pat. No. 4,830,761, Leach et al. disclose a method of recirculation cooling tower basin water through a series of filter bags in order to reduce the amount of particulate contamination. In U.S. Pat. No. 6,332,978, Cushier et al. teaches a combination of filtration and treatment with redox media to reduce contamination in recirculation cooling tower waters. However, scale is not controlled, backwashing cycles are mandatory, and the copper compounds used plate out onto the metals of the equipment. Ozone treatment, among other disadvantages, does not prevent scale formation and is restricted in application. The known prior art methods do not eliminate scale, and do not offer 24 hour/day, automatic, effective protection against legionella, scale, corrosion and microbiological contamination.