The circulating water of cooling tower systems has always been an ideal place for growth of microorganisms. The warm temperature of the water and the addition of nutrients from the scrubbed air flowing through the tower provide ideal conditions for the growth of microbes and algae. In here, these organisms multiply at fantastic rates. The result is degraded system efficiency due to blockage of flow, shortened equipment life due to corrosion, increased operating cost due to higher pumping power requirements, and the spread of disease or even death.

Traditional cooling tower water treatment involves chemical treatment with a variety of metallic compounds, organic biocides and Ph stabilisers. Although these chemicals can be somewhat effective biocides, this cocktail of chemicals and their byproducts spoil the quality of water. This, in turn, increases the quantity of blow down and thus reduces the cycles of concentration in the cooling tower. Furthermore bacteria mutate and become resistant to a chemical which necessitates a change in chemicals.

Ozone is the fastest acting and the most efficient oxidising agent against all microbiological organisms. When properly applied, ozone kills all viruses, bacteria, cysts, and algae species. Micro-organism cannot build resistance to ozone; even after prolonged use of ozone. Ozone is produced in an ozone generator and usually injected continuously into the cooling water system in a branch stream.