Novel Approaches for Biocorrosion Mitigation in Sewer Systems

Georgios Fytianos,Petros Samaras,Dimitra Banti,Efthimios Papastergiadis,Esmeralda Dushku,Minas Yiangou

doi:10.3390/chemistry3040085

Abstract

Concrete sewer pipes can be corroded by the biogenic sulfuric acid (H2SO4) generated from microbiological activities in a process called biocorrosion or microbiologically induced corrosion (MIC). In this study, inhibitors that can reduce Acidithiobacillus thiooxidans growth and thus may reduce the accumulation of biofilm components responsible for the biodegradation of concrete were used. D-tyrosine, tetrakis hydroxymethyl phosphonium sulfate (THPS) and TiO2 nanoparticles were investigated as potential inhibitors of sulfur-oxidizing bacteria (SOB) growth. Results showed that most of the chemicals used can inhibit SOB growth at a concentration lower than 100 mg/L. TiO2 nanoparticles exhibited the highest biocide effect and potential biocorrosion mitigation activity, followed by D-tyrosine and THPS.

Highlights

Concrete pipes are still being used for the construction of sewer networks worldwide
Concrete sewer pipes are corroded by the biogenic sulfuric acid (H2SO4) generated from microbiological activities in a process called biocorrosion or microbiologically induced corrosion (MIC)
Both culture media were used in our later experiments to investigate potential biocides of A. thiooxidans DSM9463

Summary

Introduction

Concrete pipes are still being used for the construction of sewer networks worldwide. Concrete sewer pipes are corroded by the biogenic sulfuric acid (H2SO4) generated from microbiological activities in a process called biocorrosion or microbiologically induced corrosion (MIC). The Thiobacillus genus, as a key bacterial manifestation onto concrete sewers, leads to the concrete’s deterioration [7,8] The product of their metabolism (i.e., sulfuric acid) results in attacks that lead to concrete degradation. Concrete sewer system biocorrosion problems can be addressed with various methods such as the application of protective coatings onto the concrete surface [11,12], biocides and chemical dosing [1]. Special emphasis was given to inhibitors that can reduce Acidithiobacillus thiooxidans growth and the subsequent sulfate production, as well as the accumulation of biofilm components responsible for biodegradation of concrete. The inhibition efficiencies of three different inhibitors (i.e., D-tyrosine, THPS and TiO2) and some of their combinations are tested

Materials and Methods

Inhibition Assays

Statistical Analysis

Results and Discussion

Conclusions