What does chlorine kill

A.� A large number of water borne disease such as typhoid fever, dysentery, cholera and Legionnaires' disease.

�

Q.� Can't anything else be used

A.� Chlorine and chlorine-based compounds are the only disinfectants that can efficiently kill most microorganisms during water treatment without affecting the quality of our drinking water.

�

Q.� How does chlorine work

A.� Although chlorine has been used for some time the way in which this element destroys harmful microorganisms isn't completely understood. The most recent research suggests that chlorine disrupts a bacteria's cell wall, which functions as its barrier to the outside wall, and so eventually kills it.

�

Q.� Can I detect chlorine in my water

A.� In order to be an effective disinfectant of micro organisms chlorine needs to be added to the water in sufficient, yet safe, quantities and must have a sufficient amount of time to react: the so called contact time. The optimum contact time is usually 30 minutes.

�

To ensure continued protection against harmful organisms, a certain amount of chlorine must remain in the water after treatment. The remaining chlorine is known as a residual chlorine. It is this tiny amount that you sometimes smell in your tap water.

�

Q.� Why doesn't chlorine harm us

A.� As chlorine is so effective at destroying so many microorganisms it may be surprising that we can tolerate its presence in our drinking water. However any chlorine that makes it into our digestive system is quickly neutralised by it. So the concentrations of chlorine in our system never reaches levels that would cause us harm.

�

Q.� So chlorinated water is completely safe

A.� It has to be monitored as chlorine can combine with natural organic compounds found in water to create some undesirable by products.

�

One thing is for sure without effective disinfection drinking water would be a dangerous occupation. The World health Organisation estimates that up to 5 million people die annually due to using polluted water.

�

Q.� When did water start being treated with chlorine

A.� Water treatment has been around for a few centuries, with boiling being one of the first forms of treatment. Chlorine, which is a naturally occurring element , was first used as a disinfectant at the beginning of the 20th century.

�

Want to know how something works Click here to ask.

�

by Lisa Cardy