Swimming Pool Codes - City of Fargo

CHAPTER 4 - DISINFECTIONSwimming pools receive all manners of dirt and debris and it is essential that some form ofdisinfectant be used to destroy any potentially dangerous organisms. To do this, swimmingpool disinfectants must possess certain properties. Above all others, they must be effectiveand must be capable of rapidly killing bacteria. They must have residual properties such thatthey maintain a presence in the water to eliminate bacteria and harmful organisms as theyenter the pool. A disinfectant must be safe and harmless to bathers. It should not createundesirable conditions in the pool. It must be readily available, inexpensive, easily storedand handled, and it should possess algaecidal properties.4.1 CHLORINEThe most common means of swimming pool disinfection is through the application ofchlorine. Chlorinating of pool water will provide for disinfection to kill bacteria and diseaseproducingmicroorganisms, which might infect bathers and oxidation (to react with anddestroy other contaminants such as algae, body oil, minerals, dust, and other materials, whichcause color, odor, and turbidity). The advantages of using chlorine as a swimming pooldisinfectant are:A. Chlorine is effective. It possesses both bactericidal and algaecidal properties.B. It is easy to store and handle.C. It is available in a variety of forms such as a gas, liquid, or solid.D. It can be dispensed by hand or automatically through a wide variety ofdevices.E. Its presence in water is easily detected and measured.F. It is widely available and relatively inexpensive.When chlorine, in any form, is added to water a chemical reaction takes place with theresulting formation of hypochlorous acid. This is the chemical agent which reacts with anddestroys bacteria and other undesirable contaminants in pool water. The amount ofhypochlorous acid, which is produced by this reaction, is dependent on the pH of the water.Therefore, maintaining the pH within the proper range will also aid in establishing andmaintaining an adequate and effective chlorine residual.Chlorine is a very active chemical. As it is added to the water, it will react with manysubstances both dissolved and suspended in the water in the following ways: (pg 13, fig 1).10