Chlorine is used in water treatment due to its ability to disinfect and to provide residual protection against microorganisms in drinking water, process water and aquatic applications. However, chlorine in some industries and processes is unwanted due to contamination and associated chemical reactions. Chlorine can impact taste, odour and performance of a manufactured product such as in food & beverage or pharmaceutical industries. It can also cause damage to water treatment infrastructure and equipment such as RO membranes. In these instances, chlorine must be removed.
Additionally, when free chlorine reacts with organic matter in water, new chemical compounds are formed. These chloramines or combined chlorine compounds pose health risks to those exposed to them whilst being damaging to building infrastructure. Chloramines are a common problem in swimming pools. The notorious and unpleasant “swimming pool” smell is caused by chloramines. They have been linked to health problems such as eye & skin irritations and asthma. The corrosive nature of chloramines also poses a risk for swimming pool infrastructure and HVAC systems.
How Dechlorination and Chloramine Destruction is Achieved with UV
UV radiation is an effective method to remove chlorine and destroy chloramines by a process called photodegradation or photolysis. Both Low Pressure UV lamps and Medium Pressure (polychromatic) uv lamps have been shown to dechlorinate and reduce chloramines successfully.
Design of Chlorine and Chloramine Destructing UV Treatment Systems
Free chlorine and chloramine destruction using UV requires a much greater UV dose in comparison to inactivation of microorganisms in drinking water. Due to the specialist nature of this application, each chlorine or chloramine destruction requirement must be discussed prior to any solution being recommended. The amount of free chlorine or chloramine destruction required, in combination with flow rate and UV Transmission (UVT) will be considered in the UV treatment system selection.
UV-Guard uses both Low Pressure and Medium Pressure UV lamps for dichlorination and chloramine destruction depending on the nature of the project.