Working Principle
In an electromagnetic spectrum Ultraviolet lies between the x-ray region and the visible region. The range of UV is between 200 nanometers (nm) to 390 nanometers (nm). The germicidal action of Ultraviolet occurs at 260 nm.
UV is produced artificially by the conversion of electrical energy in a low pressure mercury vapor lamp. The flow of electron, between the electrodes of the lamp, through the ionized mercury vapor creates UV light.
As UV light penetrates the the cell wall of the microorganism and alter their DNA structure thereby inhibiting the further reproduction thereby rendering them harmless.
Components of UV System
Source of Electricity
The unit includes high voltage electric power source so that high dose of an UV dose can be maintained.
Chamber
An opaque chamber that is resistant to corrosion. It may be of either steel or may be of other non corrosive materials.
Ultraviolet Lamp
Ultraviolet lamp is an important source of energy and ensures effective supply of quartz sleeve. The lamp is installed in such a way that it is easy to install, operate and maintain.
Quartz Sleeves
Quartz sleeves are installed din order to transmit UV energy with much higher rate.
Mechanical Wipers
The UV system also contains mechanical wipers for maintaining transmission upto optimum level between scheduled cleaning and maintenance work.
Sensors
For monitoring the intensity of UV, Sensors are installed. It is generally connected to an alarm system that alert the operator in case the intensity is lowered.
Safety Control
Safety control in the unit shuts the UV lamps if the flow levels is lowered or the temperature of the lamp is elevated.
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here for large viewConsiderations While Operating UV System
When an Ultraviolet system is operated, UV sterilizer should be installed as the final step of treatment. This is because UV does not leave any measurable residual in the water.
To prevent the staining from iron and manganese on the quartz sleeve, it is necessary that pretreatment is done sediment filter because stains can prevent the transfer of UV energy to the water.
Total Dissolved Solids (TDS) above 500ppm can again hamper the transfer of UV energy in the water. Hence this should not be allowed.
The water turbidity should be minimum because if the turbidity is high, the UV treatment may be ineffective.
The temperature can effect the disinfection process hence the minimum operating temperature of a UV lamp must be near 400°C (1040F). The fluctuation in temperature should not be allowed as with fluctuating temperature UV levels also fluctuates.
Advantages of Ultraviolet System
The advantages of Ultraviolet Systems are as follows:
- It is environment friendly device as it neither handle dangerous chemicals nor it carries any problems of overdosing.
- For treating both potable and non potable water it is accepted universally.
- Installation and operating cost is low as compare to other systems like ozone disinfection system, chlorination etc.
- Requires no holding tanks, for immediate treatment process.
- Power consumption is low.
- It is safe to handle. Moreover, it adds no chemicals to the water as byproducts.
- It does not remove any beneficial minerals.
- The taste, odor, pH or conductivity of the water remains unaltered.
- Operation is fully automated.
- Maintenance is easy and cost effective.
- Disinfect viruses and bacteria more efficiently than chlorine.
- It can supplement other water processes like Reverse Osmosis (RO), filtration, ion exchange, etc.
Ultraviolet disinfection system is used for various applications:
- Disinfecting domestic water supplies
- They are used for producing potable water
- Pharmaceutical industries
- Distilleries
- Food and beverages
- Treatment of surface water, groundwater.
- Used in boiler feed plants, water softeners, bottled water plants.
- Dairy industries
- Pool disinfecting
- Laboratories and wineries etc.
