Microbial corrosion prevention

One of the reasons why it is important to remove suspended solids in water is that the particles can act as a source of food and housing for bacteria. Not only does this make microbiological control much harder but, high bacteria levels increase the fouling of distribution lines and especially heat transfer equipment that receive processed waters (for example, in one s household hot water heater). The removal of suspended contaminants enables chemical treatments to be at their primary jobs of scale and corrosion prevention and microbial control. 

Methods to prevent or reduce problems associated with microbial corrosion will be discussed later. Some of them are ... 

Non-oxidizing biocides include a variety of organic compounds such as glutaraldehyde, quarternary ammonium salts (QUATS), isothiazolones etc. These compounds are less critical in terms of corrosion because they do not accelerate the cathodic partial reaction. Many of them are active over a wide range of pH and temperatures. THPS, a water soluble organic compound, has been found particularly effective for preventing microbial corrosion due to SRB in oilfields [33]. Biocide... 

Krooneman J, Appeldoom P, Tropert R (2006) Detection prevention and control of microbial corrosion. Eurocorr Maastricht... 

In previous chapters, the importance of biocorrosion and its possible mechanisms were discussed. We also looked at some crucial factors that could increase the likelihood of MIC in a given system The particular focus of the chapter was the avoidance of microbial corrosion. However, almost all the time, what happeais in real life is that the system of concern has already been contaminated and the outstanding question is no longer how to prevent, but rather how to estimate the severity and extent of MIC. For instance, while for SRB-induced MIC, some investigators believe that no relationship exists between the corrosion rate and the number of the bacteria cells [1] the number of acid-producing bacteria in a system has a profound effect on the corrosion rate. 

Biofilms can promote corrosion of fouled metal surfaces in a variety of ways. This is referred to as microbiaHy influenced corrosion. Microbes act as biological catalysts promoting conventional corrosion mechanisms the simple, passive presence of the biological deposit prevents corrosion inhibitors from reaching and passivating the fouled surface microbial reactions can accelerate ongoing corrosion reactions and microbial by-products can be directly aggressive to the metal. 

Posttreatment of the permeate for potable water use can include dissolved CO2 removal to prevent corrosion (by aeration, lime treatment), chlorination for microbial control, and oxygenation to improve taste. 

The increasing occurrence of microbial and nosocomial infection has stimulated research activities into antimicrobial polymers and textiles [19, 25, 34]. Most medical textiles and polymeric materials used in hospitals are conductive to crosstransmission of diseases, as most microorganisms can survive on these materials for hours to several months [17, 26]. Thus, it would be advantageous for polymeric surfaces and textile materials to exhibit antibacterial properties so as to reduce and prevent disease transmission and cross-contamination within and from hospitals. N-halamines exhibit a similar antimicrobial potency to chlorine bleach, one of the most widely used disinfectants, but they are much more stable, less corrosive and have a considerably reduced tendency to generate halogenated hydrocarbons, making them attractive candidates for the production of antimicrobial polymeric materials. N-halamine compounds are currently used as antimicrobial additives to produce polymers with antimicrobial and biofilm-limiting activities. 

In the light of the knowledge that the earth s raw material resources are limited, the need for the development of modern microbicides which protect valuable products from loss of quality and deterioration is more urgent than ever. They not only protect a great number of perishable products from depreciation and destruction, but also prevent problems in industrial processes caused by algae, formation of slime and biofilms, and microbial induced corrosion. 

In many cases, microbially influenced corrosion can be reduced or even completely prevented by adopting adequate constructive measures. This is exemplified below for a sewage pipeline system. If the atmosphere above the sewage contains a large quantity of volatile sulfur compounds like H2S, then if concrete pipes must be used, they should be protected with an inert material that cannot be attacked by the microbially formed... 

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