Abstract
Since the mid 1970's there has been an increased interest in nontraditional biocides. Environmental pressures and limited water resources have made biocides like Ozone more attractive.
Ozone is a significantly more powerful biocide than Bromine and Chlorine. Bacteria counts in Ozonated systems are often four or five orders of magnitude less than chemically treated systems. By reducing the number of the bacteria released in the drift, Ozone can provide a healthier atmosphere in which to work.
Automatic control of Ozone concentration in the recirculating water, plus the use of Ozone compatible corrosion and scale inhibitors are critical factors in assuring the successful application of Ozone to cooling tower water systems.
The major benefits of Ozone are water conservation and reuse, no toxic biocide residual in the blowdown, cleaner heat exchanger surfaces, the elimination of handling other toxic biocides, and the elimination of the risk of a spill.
Ozone treatment has only recently been available from a company with traditional chemical treatment experience. In the mid 1970's there were a variety of individuals who advocated Ozone use as a sole water treatment, often with zero blowdown to further reduce water usage. The logic they employed and their results will be explored in this paper, focusing on the JPL facility in Pasadena, California.
The current Ozone treatment system at JPL has been in operation for more than one year. This system uses state of the art computer and Ozone technology. The results from this system are evaluated in light of the results obtained from the previous system.
