Water comes from a variety of sources, such as lakes and wells, which can be contaminated with germs that may make people sick. Germs can also contaminate water as it travels through miles of piping to get to a community. To prevent contamination with germs, water companies add a disinfectant—usually either chlorinated chemicals or chloramine—that kills disease-causing germs such as Salmonella, Campylobacter, and norovirus. Chlorine and chloramine are the major disinfectants used in public water systems.
Disinfection of swimming pool water
Micro-organisms polluted swimming pools. Every swimmer adds 1.000.000 to 1.000.000.000 microorganisms to the water. The water itself contains microorganisms, as well. After oxidation a disinfectant must be added to the water to kill pathogenic microorganisms.
Disinfection methods for swimming pool water
In some countries, NaDCC chlorine disinfectant is used for both oxidation and disinfection of swimming pools. When it is added to water, NaDCC chlorine disinfectant increases the pH value. It is better to use chlorine as a disinfectant and an oxidizer at a pH value of 6,5. Often, acid is added to lower the pH value.
What is chlorination
Chlorination is the process of adding chlorine to drinking water to kill parasites, bacteria, and viruses. Different processes can be used to achieve safe levels of chlorine in drinking water. Using or drinking water with small amounts of chlorine does not cause harmful health effects and provides protection against waterborne disease outbreaks.
Combined active chlorine
Combined active chlorine is the generic term for reaction products produced by free active chlorine with organic and inorganic nitrogen pollutions. These pollutions are made of swimmers excretion products. Combined active chlorine is a complex mixture of partly unknown substances, such as chlorine ureum combinations, chloramines and chlorine kreatines.
The irritating effects of combined active chlorine are often ascribed to chloramines (NH2Cl, NHCl2, NCl3). Chloramines are volatile substances that partly escape from water as gas. Like chloroform, chloramines cause the well known 'chlorine smell' in swimming pools. The formation of di- and trichloramines increases when the free active chlorine concentration is increased and the pH value is lowered. The typical 'chlorine smell' in swimming pools arises at ureum levels of 0,5 mg/L and free active chlorine concentrations of 1,0 mg/L. There is no relation between chloramine formation and ureum concentration.
Monochloramines cause eye irritations. At normal pH levels in swimming pools, monochloramine is produced predominantly. Both di- and trichloramines irritate eyes. These substances reach the eyes through water and through the air above the pool. Trichloramine also irritates air tracts. Other chlorinated organic subtances are suspected to irritate as well, particularly chlorinated ammonia, kreatinine and urine acid. The combined active chlorine concentration in swimming pools should be below 1 mg/l.
What is chloramination
Chloramination is the process of adding chloramine to drinking water to disinfect it and kill germs. It is sometimes used as an alternative to chlorination. Chloramines are a group of chemical compounds that contain chlorine and ammonia. The particular type of chloramine used in drinking water disinfection is called monochloramine which is mixed into water at levels that kill germs but are still safe to drink.
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