Biocides and Microbiocides

Biocides and MicroBiocides are chemicals that prevent and eradicate unwanted biological fouling from the system. Biocides are of various nature such as oxidizing, non-oxidizing, cationic, anionic etc. based on compounds of 2,2-Dibromo-3-Nitrilopropion Amide (DBNPA), CIT/MIT (CMI/MIT - Isothiazolinones), Glutaraldehyde, Quaternary Ammonium Salts, Organo Sulfur Compound, Thiocarbamate, Bromo-chloro Hydantoin, TCCA, SDIC, TRIBUTYL TETRADECYL PHOSPHONIUM CHLORIDE (TTPC), 2-Bromo-2-nitro-1,3-propanediol (Bronopol), Methylene BisThiocyanate (MBT/MTe) etc.

Biological Fouling or Biofouling is the undesirable accumulation of micro-organisms, algae and diatoms, plants, and animals on surface, pipelines and heat-exchangers of cooling systems. Bio-fouling can be of aerobic (that require oxygen) or anerobic (that don't require oxygen) organisms. In general the former is found in Cooling Towers and the later in closed circuit systems.

Cooling water is the best breeding ground for micro-organisms.
Microbial problems in industrial cooling water systems is due to growth of algae, fungi and bacteria. They cause plugging, fouling, corrosion & threat to human safety. Many different kinds and species of bacteria can exist in the cooling water system at the same time.

Warm water in the cooling system is a natural habitat and breeding ground for micro-organisms. Moreover, ample sunlight and nutrients accelerate the growth rate of micro-organisms in these conditions.

It is required to eliminate micro-organisms growth from cooling system by means of proper chemical treatment program. It is also necessary to clean the cooling tower at regular intervals to destroy bacteria hideouts.

Major threats of Biological Fouling in Cooling Water System:-

Corrosion of System Metal:
Biological fouling can be a definite threat to system metal. There are several types of biological corrosion, viz.,
1. MIC (Microbiologically Induced Corrosion) - In this the microbes form a slimy layer (also known as Biofilm) on the outer side and cause corrosion of underneath metal.
2. Sulfate reducing bacteria - they produce hydrogen sulfide from dissolved sulfate in anaerobic conditions.
3. Sulfur oxidizing bacteria - produce sulfuric acid.
4. Iron oxidizing bacteria - oxidize soluble ferrous to insoluble ferric.

Threat to human - Legionella Disease:
Cooling water thrives the growth of Legionella Pneumophilia bacteria which caused life taking Legionella disease to humans when the bacteria enters the lungs through respiration. Proper biocide and microbiocide must be dosed to prevent this disease

MICROBIAL CONTROL

Microbial or Microbiological growth can be controlled in the cooling water system by dosing of proper and specific Biocides and Micro-Biocides.

It is also important to understand that Biocides are also designed and are specific on various factors such as pH of system water, temperature etc.

Any single biocide or microbiocide might not totally be capable of controlling biological fouling, if not used in alternation with another, because microbials attain immunity for any particular biocide dosed for a long period.

Just like biocides, Biodispersants are also equally important to control microbial growth by removing biofilms which is a complex slimy layer that protects microbials from biocides.

Chemtex offers a wide range of effective biocides, microbiocides and biodispersants for control of microbials, algae, fungi and bacteria in the cooling water and closed circuit chilled water/brine and glycol systems under its registered trade names of ALSTACIDE for:-