Cooling towers, Evaporation Condensers and Legionnaires'
disease.
The most important reason for using biocides in cooling
towers is to prevent the growth of Legionella. The various
Legionella species are the cause of Legionnaires' disease
in humans and transmission is via exposure to aerosols—the
inhalation of mist droplets containing the bacteria.
Common sources of Legionella include cooling towers
used in open recirculating evaporative cooling water
systems, domestic hot water systems, fountains, and
similar disseminators that tap into a public water supply.
French researchers found that Legionella spread through
the air up to 6 kilometres from a large contaminated
cooling tower at a petrochemical plant in Pas-de-Calais,
France. That outbreak killed 21 of the 86 people that
had a laboratory-confirmed infection.
Biodispersants
Wells Water Treatment will provide a wide range of
biodispersants to prevent and remove scale, corrosion
and fouling from the cooling tower.
Scale forms when dissolved minerals and salts precipitate
out of the water that they are dissolved in and bond
to adjacent surfaces. Scale not only harbors the bacteria
that causes Legionnaires’ disease, it also causes
blockages in pipe work and reduces efficiency.
In most cases dissolved oxygen is the primary cause
of corrosion although 'mixed metal systems' can also
suffer from corrosion through galvanic action. Corrosion
eats away costly system components and corrosion products
can cause staining and sludging. If pre commission cleaning
has been missed or carried out incorrectly, then mill
scale, rust, grease and other residues can cause severe
operating problems.
Most systems provide ideal conditions for one or more
of the common micro-organisms such as bacteria, fungi
and algae to multiply quickly and cause organic fouling.
Apart from the obvious problems of blockage and poor
heat transfer, organic fouling presents an inevitable
health hazard.
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