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Chlorine has long been added to water as it is an inexpensive, effective and easy to operate way to deal with bacteria in water. When added in a proportion to flow manner and where levels are monitored properly it is not normally detected by consumers.
Chlorine demand
When chlorine is added to water some of it is used up in reacting with bacteria in the water, more is used up in reacting with any iron, manganese or organic matter present. This is often referred to as the chlorine demand of the supply. When calculating the amount of chlorine solution to add, the chlorine demand must be taken into account.
Chlorine has long been added to water as it is an inexpensive, effective and easy to operate way to deal with bacteria in water. When added in a proportion to flow manner and where levels are monitored properly it is not normally detected by consumers.
Contact time
When chlorine is added to water it must react for some time before the water can be considered safe to drink. This is called the contact time. The length of time required can be a minimum of 15 minutes and in some situations can be 30 minutes. Provision must be made for this in the installation of the chlorine injection system.
The contact time can be provided by an in line pressure tank or by using a storage tank. Note when a storage tank is used that the pressure is lost and a pump is required after the storage tank to deliver the water forward. As a general rule, low volume situations use a pressure tank and high volume situations use a tank or reservoir to provide the contact time.
Drinking water with chlorine added
At the levels usually used to disinfect water, chlorine is safe to drink. However, where the taste of chlorine is found to be objectionable, simple carbon filters can be used to remove it at the point of use. For a single tap, the best solution is a small in line filter housing containing a carbon cartridge. More information on these is available on request.
Injection mechanism
The picture above shows the pump and meter set which is used to add the sodium hypochlorite solution to the water. The system includes, dosing pump, ¾”meter (larger meters are also available), Dosing tank and bund. The contact tank is not shown
Other applications
Chlorine is also used to assist in the removal of hydrogen sulphide from water supplies.
We can also supply Ultraviolet filtration for control of bacteria.