The Effect of Chlorine on Bacteria

Chlorine is a product of sodium, carnallite and sylvite, according to the Radiochemestry Society. It was discovered by Scheele in 1774 and named in 1810 by Davy. Chlorine is a green-yellow gas, and is commonly used in pools, in public drinking water and as a cleaning product, because it kills bacteria.

Process

• According to "Scientific American" magazine, chlorine becomes hydrochlorite and hypochlorous acid in water. These compounds destroy the bacterial cell because they react with biomolecules. Chlorine attacks the cell wall which in turn prevents the cell's vital functions. This kills the microorganism. Live Science studied the reaction further and discovered that the chlorine causes the protein in the cells to lump together and become inactive, killing the bacteria.

Drinking Water

• According to "Scientific American," officials started using chlorine to treat drinking water in 1908. It is used in 98 percent of all municipal water supplies. Chlorine is used in municipal water supplies to kill bacteria and disinfect the water. Chlorine kills many microbial waterborne pathogens, including dysentery, cholera and typhoid fever. Not only are bacteria and pathogens killed during the treatment process, but the water remains clean all the way to the consumers' water faucets.

Health

• Chlorine is commonly used as a household or commercial cleaning agent, and it is washed down the drain. Unfortunately, it is hazardous to the environment and your health. In fact, immune cells produce hypochlorite to fend off infections and bacteria, but this hypochlorite also damages human cells, causing chronic inflammation. Exposure to high concentrations of chlorine causes fluid to build up in your lungs. Vomiting, chest pain, watery eyes, coughing and light-headedness will occur if you drink chlorine solutions. Irritation and burning will occur if your skin or eyes are exposed to chlorine. Eye, nose and throat tissues will be permanently damaged if they are exposed to chlorine vapor.

Effectiveness

• Chlorine's effectiveness at killing bacteria depends on the concentration of chlorine in the water. It also depends on the chlorine demand of the water and the length of time the chlorine is in contact with the organism. Water quality is also a factor. As water temperature increases, chlorine becomes more effective. If water is alkaline, or as the pH rises, chlorine becomes less effective. Cloudy water inhibits chlorine's effectiveness also. If you have a lot of minerals in your water, such as iron, hydrogen sulfide and manganese, chlorine bonds with these minerals. As chlorine bonds to other minerals, less chlorine is available for water treatment and bacteria removal. As the concentration increases, the rate of disinfection increases, so less time is required for the chlorine to kill organisms.