ULTRA
VIOLET BACTERICIDAL LAMPS
Trojan,
Sterilite, Wonderlite
INDUSTRIAL
ENTERPRISES
Ultraviolet
Disinfection
Ultra-violet
radiation (or UV) is a proven process for disinfecting water, air or solid surfaces that are microbiologically
contaminated.
The effects of UV as
a disinfection agent have been documented since the early days of research in
biology and the physics of light waves.
The
U.S. Environmental Protection Agency recognizes the use of ultra-violet as a
proven, viable technology;
"Ultraviolet
(UV) radiation has been found to be an effective disinfectant…. Simplicity of
installation, ease of operation and maintenance, and low costs relative to
chemical disinfection, make UV a useful small systems disinfection technology
option."
Ultraviolet
is recognized as superior compared to other methods of disinfection;
·
UV
is very safe. There are no dangerous chemicals to handle or monitor.
Disinfection results are immediate.
·
UV
has a low initial system cost and a very low cost of operation.
·
UV
is environmentally friendly. There are no byproducts from the UV process, and
nothing is discharged into the environment.
·
UV
causes no change to the taste or odor of the water disinfected. It is
impossible to over-treat water with UV.
·
UV
does not remove any of the minerals, which are a health benefit and provide
water with its good taste
·
UV
systems are very easy to install and maintain.
·
UV
disinfection is compatible with all other forms of water treatment.
Ultraviolet light
penetrates the cell wall of a microorganism and causes a reaction in the
microorganisms DNA (deoxyribonucleic acid), which breaks the C=C carbon bond in
the molecules of the microorganism.
This causes cellular death, rendering
the microorganism incapable of growing and multiplying.
UV Dosage
Through research,
biologists have determined the amount of UV required to destroy different kinds
of microorganisms.
The amount of UV required is termed the
dosage, and is a function of a certain intensity of UV (expressed in power or
microwatts), delivered for a given period of time (seconds), over a given area
(square centimeters).
Power X Time X Area or microwatt-sec/cm2 (µW-s/cm2)
A short exposure time at high intensity
can be as effective as a long exposure time at lower intensity, as long as the
product of power multiplied by time is the same.
The UV reactor design is critical to
obtaining proper UV dosage of water.
The water entering the UV chamber must
be sufficiently free of suspended solids such that the microorganisms (some of
which, like viruses, are extremely small) cannot hide behind or "in the
shadows of" particles floating in the water.
Then the flow-rate of the water must
match the power of the lamp so that the microorganism has time to absorb the UV
radiation and be destroyed.
Good design of the UV chamber itself
promotes uniform water speed in the hydraulic flow through the chamber,
insuring maximum average UV exposure.
Low-pressure mercury discharge lamps
(similar in construction and operation to fluorescent lamps), emit a wavelength
of 253.7nm, which has been found to be a good source for UV radiation to
perform the disinfection process.
An electric arc,
struck the length of the lamp, travels through an inert gas containing mercury.
The arc heat vaporizes some of the mercury, which becomes ionized in the
electric arc and gives off UV radiation.
The UV lamp is
constructed using a special quartz glass, which easily passes
the UV radiation through it.
The UV lamp is
slipped into a quartz glass sleeve which is
submerged in the stream of water. As the water flows past the lamp the
microorganisms in the water are exposed to UV radiation.
The quartz sleeve
prevents the water from contacting the lamp, which would change the temperature
of the lamp glass (and affect the
pressure of mercury in the lamp and in turn the level of UV output).
Ultraviolet
radiation
Ultraviolet
light is electromagnetic radiation in the spectrum with a wave length between
100 and 400 nanometers (nm). The ultraviolet spectrum can be divided into three
bands (several different divisions of this band exist);
UV-A 320 to 400 nm
UV-B 280 to 320 nm
UV-C 100 to 280 nm
The UV-C band
contains the wavelengths (250-270nm) which have been found to be very effective
in destroying many microorganisms (optimum wavelength is 265nm).
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Multi-Media Filter, Highly-Activated Carbon Filter, Zeolite-Process Water Softener With Brine Tank, Fiberglass Ballast-Type Pressure Tank (fully automatic backwash & regeneration) |
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Aganan, Pavia, Iloilo, Philippines
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