Chlorine disinfection refers to the process of deactivating microorganisms. Chlorine disinfectant is used in drinking water, swimming pools, and wastewater along with general household cleaning. The different methods for chlorine disinfection include bleaching, water filtration and water purification.
Chlorine disinfection using bleach is a common form of household cleaning. Bleach is made of chlorine gas mixed with an alkali solution such as sodium hydroxide. When used to disinfectant areas in the home such as counter tops or floors, the bleach reacts with the microorganisms or germs, and kills them by breaking down their molecules' chemical bonds.
Water filtration is another form of chlorine disinfection. A chlorine filter system is the most common form of swimming pool water filtration. Chlorine in the form of hypochlorous acid or hypochlorite is added to the water to initially kill any bacteria that may be living in the pool water. Concentrations of the chlorinated water are tested through pH strips to ensure levels are around seven. A seven pH level should keep bacteria under control and not be harmful or irritating to humans.
Filters skim out any large debris or algae that formed while the chlorine keeps the swimming pool safe for humans to swim. When the pH levels increase due to lack of chlorine, microorganisms grow rapidly and may cause illness for swimmers. Testing for pH levels is performed regularly and additional chlorine is added when needed to keep the pH levels in check.
Water purification is one of the most important methods of chlorine disinfection. Though many processes for water purification are used, such as flocculation, filters, and electromagnetic radiation, the most common method is chlorination. The World Health Organization (WHO) recommends chlorination as a preferred alternative to drinking water from streams and rivers because the level of pollutants in chlorinated water is extremely low. Many third world countries do not have the funds to provide safe drinking water, so boiling water is often necessary to prevent illness.
Water purification plants exist in every municipality in the United States. While some are very small, they all employ some form of a filtration then chlorination technique. Water is pumped into the treatment plant and put into holding tanks. The water moves through a screen filter to remove any large particles such as sticks, leaves or trash. A chlorine compound of chlorine gas and sodium hypochlorite is then added to kill any bacteria that may be present.