Question # 601

601. How can one estimate emissions of chlorine from use in cooling water treatment? We have tried to estimate the emissions for some cooling water systems based on the amount of water evaporation, wind drift and the amount of chlorine used, but the releases seem too high.
Estimating emissions based on the amount used overestimates releases since chlorine is only slightly soluble in water, it reacts with chemicals in the water and it dissipates in side reactions. Multiplying measured residual chlorine by recirculation rate by lost water fraction may also overestimate releases (residual includes other forms of chlorine), but may be the only way to make a reasonable estimate. Please refer to EPA’s EPCRA section 313 Reporting Guidance for Food Processors (EPA 745-R-98-011; August 1998).