OF ULTRAVIOLET SYSTEMS
Ultraviolet rays are part of the
light that comes from the sun. UV is known to be an effective
disinfectant due to its strong germicidal (inactivating) ability.
UV has been used commercially for many years in the pharmaceutical,
cosmetic, beverage and electronic industries. It was used
for drinking water disinfection in the early 1900’s
but was abandoned due to high operating cost, unreliable equipment,
and the expanding popularity of disinfection by chlorination.
Recently, the safety of chlorination has been
questioned and UV has experienced increased acceptance in
both municipal and household systems. There are few large-scale
UV water treatment plants in the United States although there
are more than 2,000 such plants in Europe. Municipal systems
use UV in conjunction with chlorine, thus reducing the amount
of chlorine for disinfection.
UV radiations has disinfection properties that
inactivate bacteria, viruses, spores, cysts etc. UV is effective
only if the light intensity reaches the organism in question,
therefore nothing should be present in the water that shields
the organism from radiation.
UV radiation has
three wave length zones: UV- A, UV- B and UV- C. It is the
short wave UV- C that has germicidal properties for disinfection.
A low-pressure mercury lamp produces the UV light in the range
of 254 Nanometers (nm). An nm is one billionth of a meter
(10^-9 meter). 254 nm is the most effective on microorganisms
and hence it is perfect for germicidal activity. There are
UV lamps that produce radiation in the range of 185 nm that
are effective on microorganisms and will also reduce the Total
Organic Carbon (TOC) content of the water.
In a typical UV system, approximately 95% of
the radiation passes to a special quartz glass sleeve and
into the untreated water. Used alone, UV radiation does not
improve the taste, odour, or clarity of water. There is no
residual disinfection in the water to inactivate bacteria
that may be introduced after the water passes the UV chamber.
The percentage of microorganisms destroyed depends on the
intensity of the UV light and the contact time. If material
builds up on the quartz sleeve (fouling), the light intensity
and the effectiveness of UV is reduced.
'Good Life UV' from Good Life Products has none
of the disadvantages of earlier ultraviolet systems, because
water flows through Dupont's special quality Teflon® tubes,
Good Life UV systems eliminates fragile quartz tubes and all
their disadvantages. A special Flow Pattern through the Teflon®
tubes assures full exposure to the ultraviolet rays. Non wetting
surface characteristics of Teflon® also eliminate any
build up of contaminants that could block ultraviolet rays
i.e. there is no fouling occurring in the system.
OF DIFFERENT DISINFECTION METHODS WITH UV