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

C. Grengg*, F. Mittermayr, G. Koraimann, F. Konrad, M. Szabó, A. Demeny, M. Dietzel

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

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 4 cm 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 > 1 cm yr− 1.

Original languageEnglish
Pages (from-to)93-101
Number of pages9
JournalCement and Concrete Research
Volume101
DOIs
Publication statusPublished - 1 Nov 2017

Keywords

  • Acid corrosion
  • Concrete
  • EMPA
  • Micro XRD
  • Microbiological corrosion
  • Sulphuric acid

ASJC Scopus subject areas

  • Building and Construction
  • Materials Science(all)

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