Microbiological Control

Microbiological control is critical to the control of corrosion and scale in cooling and process water systems. Biofilm is known to have significant insulting properties that can reduce heat transfer. Control of dangerous water borne organisms is also important in all industrial and commercial applications.

MIC (microbiologically influenced corrosion) and MID (microbiologically influenced deposits) are important considerations in many water systems.

The relationships between corrosion and microbiological activity are found in many areas. Some of these include:

Because of these many forms of MIC it is important to consider the planktonic (free floating) forms of microbiological organism as well as the sessile (depositing) forms of bacteria.

Microbiologically Influenced Deposits (MID) may be in the form of biofilms but is often found as biomass with entrapped debris.

Biofilms also often lead to the formation of mineral scales . Calcium ions are fixed into the biofilm by the attraction of carboxylate functional groups on the outer polysaccharide layers of the biofilm. This would then provide nucleation or crystal growth sites Additionally, biofilms may entrap precipitated calcium salts and corrosion by-products from the bulk water that will act as crystal growth sites.

The use of mechanical, operational and chemical means of microbiological control are necessary to provide the most cost effective treatment programs.

The effective use of oxidizing biocides (chlorine, hypochlorite, bromine), penetrating oxidizing biocides (chlorine dioxide and ozone) and biodispersants are the technical backbone of cost effective chemical treatment for microbiological control.

Non-oxidizing biocides are effective in responding to systems that require cleanup and/or systems which have special contaminants. These biocides are targeted to specific organisms or operating conditions.