Evaluation of Ozone Treatment in Air Conditioning Cooling Towers. Final Report

摘要

Ozone is a potential alternative to chlorine and proprietary chemicals for treating cooling tower circulating water systems at electric power plants. This study surveyed air conditioning cooling tower systems which have used ozone treatment for the past few years. The performance of these systems and the implications of using ozone treatment in electric power plants were examined. Several sites were surveyed. Makeup and circulating water samples were taken at four sites using ozone treatment. The samples were analyzed for general mineral content, including parameters which affect chemical scaling. At two of these sites, cooling tower systems using proprietary chemical treatments were sampled for comparison. At selected sites, trihalomethanes, total plate counts, oxidant residuals, and trace metals were measured. The results indicate that ozone treatment warrants further study for application at electric power plants. For the ozone systems sampled, biological fouling was apparently controlled. The ozone systems operated at conditions far exceeding conventional chemical scale limitations. As a result chemicals were apparently precipitated, but seemingly settled out in the cooling tower basins rather than fouling heat exchange surfaces. The failure of one system operating at elevated water temperatures indicates that the limits of ozone treatment must be determined before this technology is applied at electric power plants. (ERA citation 05:008436)