![]() ![]() Combined residual is determined by calculation:ģ. Because bromamines can be good biocides, the total residual is sometimes used to monitor bromine treated systems.įree and total halogen residuals can be directly measured using DPD test methods. Total halogen residual is the sum of the free and combined chlorine and/or bromine residuals. Where a stabilized chlorine or bromine biocide is used, it also measures the oxidant bound to a nitrogen based stabilizer. Unlike chloramines, bromamines can be effective biocides. However, the Oxidation Reduction Potential (ORP) of the water does vary with pH, with the ORP decreasing as the pH increases reflecting its reduced strength as an oxidizer.Ĭombined halogen residual measures the concentration of oxidant that has been consumed in reactions with any ammonia, nitrite, or organic nitrogen to form a range of chloramine and/or bromamine compounds. ![]() The free residual does not vary with changes in pH. Some halogens generate both chlorine and bromine. Unlike chlorine, bromine is an effective oxidizer across the pH range in which cooling towers operate. Where bromine is used, the free residual measures the amount of hypobromous acid and hypobromite ion. In chlorine treated systems, the free residual reflects the amount of hypochlorous acid and hypochlorite ion in solution. ![]() It is typically the best measure of biocidal efficacy. To avoid confusion, halogen test residuals are typically reported as ppm of chlorine (Cl 2) whether the biocide contains chlorine, bromine, or produces a mixture of both.įree and Total Chlorine test results can be used to monitor three types of oxidizer residuals:įree halogen residual measures the concentration of unreacted chlorine and/or bromine available to kill microorganisms. Standard DPD test method does not distinguish between chlorine and bromineĭPD free and total chlorine test methods are not specific for chlorine or bromine. However, there are some important things you need to understand about halogen testing in cooling towers that will help you use the results for maximum benefit.ġ. The DPD test commonly used for measuring chlorine and bromine residuals in cooling towers is simple, quick, and relatively accurate. High residuals can cause corrosion and destroy inhibitors. Low residuals can result in poor microbiological control. Routine testing is important to confirm effective halogen residuals are maintained. These halogen compounds form strong oxidizing agents in water, which is how they kill bacteria and other microorganisms. Chlorine and bromine based biocides are widely used for microbiological control in cooling tower systems. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
December 2022
Categories |