Biocides bacterial corrosion

Thus an effective control of bacteria responsible for these undesired effects is mandatory. Several biocides and nonbiocidal techniques to control bacterial corrosion are available, and procedures and techniques to detect bacteria have been developed. 

Waterside problems that lead to decreases in efficiency and material deterioration can be caused by a variety of mechanisms, such as electrochemical corrosion and deposition of foulants. These problems can be exacerbated by low flow, poor operational practice, process contamination, or specific stresses. It is also important to try to determine cause and effect relationships in order to provide a logical and practical water treatment solution. Such a solution will usually involve some form of cleaning, plus a combined engineering and chemical action plan. Inspection may be made easier by the use of a Boroscope or similar optical/video recording device. The color, texture, and quantity of all deposits should be noted, measurements of pits taken, and microbiological contaminants analyzed. It may be useful to conduct biocide efficiency tests on bacterial slimes. The period when a heat exchanger is open for inspection may be an opportune time for the permanent installation of ports for corrosion-monitoring probes. 

Uses Preservative and mildew Inhibitor for paper, textiles, food-pkg. adhesives biocide for rubber, wax corrosion inhibitor for nonferrous metals, antifreeze, hydraulic fluid, coolants metal deactivator flotation collector chemical intermediate copper corrosion inhibitor in water treatment protects starch and casein coatings from bacterial or fungal activity preservative for defoamers in food-contact coatings and paper/paperboard slimicide in food-contact paper/paperboard preservative in food-contact textiles and animal glues Regulatay FDA 21 CFR 175.105,176.200,176.210,176.300,177.2800, 178.3120,181.30... 

Silver-based eompounds are inereasingly being used as biocides. Silver acts by reacting with the sites at whieh microorganisms would otherwise bond and reproduce. It does not have corrosive properties and does not contribute to the build-up of bacterial resistance to antibiotics. 

To avoid corrosion due to SRB one must create aerobic conditions. For buried pipes one generally uses a porous backfill material such as sand or gravel for this purpose. In addition, cathodic protection (see following section) can be applied. In closed systems, on the other hand, addition of biocides is an efficient method to stop bacterial growth. 

Biocides are substances one adds to the environment in order to prevent bacterial growth. With regard to corrosion, they can be viewed as inhibitors of MIC. Certain metal ions produced by corrosion, notably copper ions, can also inhibit the growth of bacteria. However, some bacteria such as thiobacillus are resistant to copper ions in small concentration and for this reason, cases of MIC of copper pipes in hot water systems have been reported in the literature [32]. 

Micro-organisms are common to drilling and completion fluids and can produce hydrogen sulfide, carbon dioxide, or organic acids. Some bacterial species, including Desulfovibrio desulfuricans, also increase corrosion by metabobcally depolarizing the cathode. Because of the prohfic nature of bacteria in these environments, both biostats and biocides are often used for their control. 

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