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  • Author or Editor: Vlasta Harbuľáková x
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The activity of microorganisms plays a very important function in the whole spectrum of degradation processes such as corrosion of metals and concrete, the plugging of the pipeline and filters in consequence of the biofilms creation or the efficiency reduction of heat exchangers. The microorganisms that cause microbiologically influenced corrosion of concrete are ubiquitous in the environment and they produce either organic or inorganic acids that can dissolve and disintegrate the concrete matrix. This paper is focused on the concrete biocorrosion’s study in real sulfuretum conditions — in a sewer pipe with wastewater in Košice city. Concrete samples with addition of 5 and 10% of coal fly ash respectively as well as reference samples without coal fly ash addition were used for the experiment. The weight changes and surface changes of concrete samples were valuated after 4-month exposition to the real sulfuretum influence. The concrete biodeterioration studies in sewer pipes suggest the analogical biodegradation processes for all samples, whereby the composition of concrete and duration of aggressive environment influence are also important.

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Pollack Periodica
Authors: Vlasta Harbul’áková, Alena Luptáková, Nadežda Števulová, and Pavlína Rutarová

Biocorrosion of natural and synthetic materials is an irreversible biochemical process, where a significant participation of bacteria societies takes place. The biocorrosion of concrete sewer pipes is caused mainly by the sulphuric bacteria and sulphate-reducing bacteria (SRB) forming a part of the biological circulation of sulphur and its compounds in biosphere. The aim of this work was to simulate a biocorrosion and to study the effect of simultaneous action of Acidithiobacillus thiooxidans ( A.t. ) and sulfate-reducing bacteria on concrete samples under model conditions. The biocorrosion effect has been proved and a further study is planed.

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Pollack Periodica
Authors: Vlasta Harbuľáková, Adriana Eštoková, Alena Luptáková, Nadežda Števulová, and Gabriel Janák

Biodeterioration can be seen as a process, which decreases value of materials and constructions and has been defined as the deterioration of materials of economic importance by organisms. Since the discovery bacterial genus Acidithiobacillus caused rapid corrosion of concrete especially Acidithiobacillus thiooxidans .This paper presents the results of concrete specimens’ biodeterioration study by bacteria Acidithiobacillus thiooxidans and Desulfovibrio genera under model conditions. Biodeterioration was carried out in laboratory reactor, where simultaneous effect of Acidithiobacillus thiooxidans and Desulfovibrio genera happened. The pH values of leachate, mass of concrete specimens change, Ca and Fe content in leachate were evaluated. After experiment the morphology of corroded surface were observed by scanning electron microscopy.

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