Cooling Tower Biocides
The chemicals used to control microbiological fouling are
referred to as biocides. Microbiological fouling is defined as the build-up of
any biological substance in a system. Treating microbiological fouling takes
persistence because the environment inside a cooling tower is typically a
breeding ground for biological growths such as algae, bacteria, and fungi. Slime
created by these organisms serves as a surface for scale formation, which can
lead to increased corrosion, restricted water flow, and reduced system
efficiency.
Oxidizing biocides are chemicals that work by
disrupting cell membranes from carrying out their metabolic process. Stronger
biocides can even break down the cell wall entirely. Oxidizing biocides also
require constant feeding in order to remain effective. Some oxidizing include: Chlorine, Bromine,
Iodine, Chlorine dioxide, Ozone, Hydrogen peroxide
Non-oxidizing biocides are organic chemicals
that absorb through cell membranes and disrupt the metabolic process from
within by inhibiting enzyme production. Non-oxidizing biocides are typically
more expensive, but do not require constant feeding because residual chemical
can last in a system for several days.
Some non-oxidizing biocides include:
Isothiazolines, 2,2 Dibromo-3-nitrilopropionamide (DBNPA), Carbamates, Gluteraldehyde,
Methylene bisthiocyanate (MBT), Polyquaternary amines, Tetrehydro-3,5,
dimethyl-2H-1,3,5 thiadiazine-2-thion,e 2-(tert-butlyamino)-4-chloro-6-
(ethylamino)-S-triazine