Understanding Corrosion in Water Pipelines: A Guide for Pipeline Designers



Last updated: May 23, 2019

What Does Microbiocide Mean?

A microbiocide is any biocidal compound or substance with the purpose of reducing the infectivity of microbes, such as viruses or bacteria. The application of a microbiocide is usually a secondary step following cleaning, or in some cases a supplementary factor in conjunction with the chemical/physical cleaning. Microbiocides are used for the protection of materials from forming biofilm and bio-corrosion. Microbiocides also inhibit slime formation and microbiologically induced corrosion.


Corrosionpedia Explains Microbiocide

Microbiocides inhibit the growth and reproduction of microorganisms in a variety of ways. Some alter the permeability of the walls, thereby interfering with the vital life processes of the microorganism. Heavy metal-based microbiocides penetrate the cell into the cytoplasm, and destroy the protein or complex with other compounds to "poison" the cell. Surfactant-types of microbiocides damage the cell, affecting its differential permeability, disrupting the normal flow of nutrients into the cell and the discharge of wastes from the cell.

The microbiocides most commonly used for cooling water treatment are usually classified into two groups: oxidizing or non-oxidizing. Chlorine-yielding chemicals and ozone are oxidizing microbiocides. Chlorine as an oxidizing microbiocide has the advantages of low cost and broad-spectrum effectiveness. In industrial process water treatment its limitations include ineffectiveness at high pH, inactivation by sunlight and aeration and corrosiveness to metals. However, ozone is a strong and naturally unstable oxidizing microbiocide used for specific applications in process cooling water systems.

Due to limitations of chlorine and other oxidizing microbiocides, and to the increased use of alkaline scale and corrosion control programs, non-oxidizing microbiocides are becoming more widely used as a primary microorganism control treatment, or as a supplement to oxidizing microbiocides. The most widely used type is quaternary ammonium salts.

In the case of heavy microbiological problems, along with alkaline treatment, use of non-oxidizing microbiocide is also necessary. Non-oxidizing microbiocides are toxic but biodegradable. Microbiocides based on aqueous solutions of glutaraldehyde are becoming more widely used where activity against troublesome bacteria, including those associated with microbiologically induced corrosion, is required.




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