The decisive role of acidophilic bacteria in concrete sewer networks: A new model for fast progressing microbial concrete corrosion

This study introduces a novel approach intertwining analytics of spatial microbial distribution with chemical, mineralogical and (micro)structural related aspects in corroded concrete sewer environments. Samples containing up to 4cm thick corrosion layers were collected from concrete manholes and an...

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Bibliographic Details
Published in:Cement and concrete research 2017-11, Vol.101, p.93-101
Main Authors: Grengg, C., Mittermayr, F., Koraimann, G., Konrad, F., Szabó, M., Demeny, A., Dietzel, M.
Format: Article
Language:English
Subjects:
Acid corrosion
Bacteria
Bacterial corrosion
Biological activity
Chemical precipitation
Concrete
Corrosion products
Corrosion rate
Corrosion tests
Deoxyribonucleic acid
DNA
EMPA
Geochemistry
Iron
Manholes
Micro XRD
Microbial corrosion
Microbiological corrosion
Oxidation
Ribonucleic acid
RNA
Sewer systems
Sulphuric acid
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Summary:This study introduces a novel approach intertwining analytics of spatial microbial distribution with chemical, mineralogical and (micro)structural related aspects in corroded concrete sewer environments. Samples containing up to 4cm thick corrosion layers were collected from concrete manholes and analysed using hydro-geochemical, microbiological, biochemical and mineralogical methods. Opposed to the current opinion DNA and RNA indicating microbial activity were found throughout the entire deterioration layer down to the corrosion front. Elemental distributions of corresponding areas revealed a dynamic pH- and diffusion-controlled system in which a distinct succession of elemental accumulations was unequivocally correlated with responding pH levels, associated dissolution and precipitation of solids, as well as with the spatially resolved presence of microbes. Microbial activity further coincided with massive iron deposition zones, within the inner anoxic to anaerobic corrosion layers. As a possible microbial catalyst for iron oxidation and in-situ acid production in this zone, we propose Acidithiobacillus ferrooxidans which were isolated from the deteriorated concrete. Based on the data we propose a new model in which biogenic induced in-situ acid production is a decisive factor, steering high concrete corrosion rates of >1cmyr−1. [Display omitted]
ISSN:0008-8846
1873-3948
DOI:10.1016/j.cemconres.2017.08.020