Concrete deterioration by bacteriogenically induced sulfuric acid attack (original) (raw)
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Microbially induced corrosion (MIC) of concrete is a major cause of deterioration in sanitary sewer systems and requires considerable amount of rehabilitation investment every year. MIC is caused by the production of hydrogen sulfide by sulfur oxidizing microorganisms present inside the sanitary sewers. The objective of this paper is to investigate solutions for reduction and/or elimination of MIC in the concrete sanitary sewers. This study reviews the cement chemistry, basic science behind concrete deterioration, and MIC production that takes place due to various biological processes which lead to the production of dilute sulfuric acid. Historical attempts to fortify concrete along with methods to reduce odors and corrosion by treatment of raw sewage are discussed. Experimental testing as per ASTM D4783 standard shows resistance of concrete samples to microbial attack with the use of antimicrobial additives.
Microbiologically induced concrete corrosion: A case study from a combined sewer network
Cement and Concrete Research, 2015
In this study, a strongly deteriorated concrete-based sewer system was investigated by using a multi proxy approach based on gaseous, hydro-geochemical, microbiological, mineralogical and mechanical analyses. Therefore, gas, liquid, and solid samples were taken throughout the entire sewer system. Long term measurements of gaseous hydrogen sulfide (H 2 S) within the sewer atmosphere yielded concentrations up to 367 ppm. Interstitial fluids, extracted from deteriorated concrete by squeezing, contained sulfate (SO 4 2-) concentrations of up to 104 g l-1 at strong acidic conditions (0.7 > pH > 3.1) and are close to the saturation state of gypsum. This sulfuric acid attack is indicative for a wellestablished biofilm containing sulfide oxidizing bacteria (SOB), which was analyzed to consist mainly of Acidithiobacillus thiooxidans. The micro-structure of the attacked concrete displays a progressing alteration zone, which is caused by microbially induced concrete corrosion (MICC), with a suggested pH gradient from about 13 to < 1, from the intact inner concrete zone to the outermost heavily deteriorated concrete. Calcium sulfate minerals such as gypsum (CaSO 4 •2H 2 O), bassanite (CaSO 4 •1/2H 2 O) and anhydrite (CaSO 4) are abundant in the altered concrete, which were formed from the dissolution of the cement phases and Ca-bearing aggregates. Remarkably high corrosion rates of different precast concrete manholes were quantified to reach values greater than 1 cm yr-1 , despite the fact that C 3 A-free cement, fly ash and a w/c of ~0.35 was used.
Study on Microbiologically Induced Corrosion of Concrete in Sewer Waste Water
International Journal of Advances in Scientific Research and Engineering (ijasre), 2021
Concrete infrastructures that make up the sewer system exposed to sewer wastewaters are often subjected to microbial corrosion. The activity of sulfur-oxidizing bacteria Acidithiobacillus sp leads to the formation of biogenic sulfuric acid. The biogenic sulfuric acid plays a very vital role in sulfate attack on concrete leading to loss of concrete mass and deterioration. This paper presents the results of a laboratory study of concrete biodegradation by the activity of SOB A.thiooxidans. Concrete samples were immersed in real sewer wastewater under laboratory conditions for 14 months. Changes in chemical composition, weight loss, and sulfate concentration variation in the laboratory sewer were investigated. The influence of biogenic sulfuric acid on biocorrosion of concrete samples was determined in terms of weight loss, formation of corrosion by-products and bioleaching of Ca and Si ions leachates. The weight loss varied in the range 0.031-0.263 mm/yr. Changes in sample morphology and byproducts formed were observed by X-ray diffraction and SEM methods. The results of morphologic changes showed the formation of gypsum and ettringite with corrosion progression.
Stable Isotope Signatures within Microbial Induced Concrete Corrosion: A Field Study
Procedia Earth and Planetary Science, 2015
In this study we analyzed a heavily damaged sewage system, exposed to microbial induced concrete corrosion (MICC). Understanding the causes, the underlying reaction mechanisms and environmental controls of MICC is crucial in order to provide sustainable restoration strategies. Various decisive parameters for detecting alteration features were determined in the field and laboratory including (i) temperature, pH, alkalinity, chemical composition of the solutions, (ii) chemical and mineralogical composition of solids, and (iii) concentration of gaseous H 2 S, CH 4 and CO 2 within the sewer pipe atmosphere. Focus was laid on stable sulfur, oxygen and hydrogen isotope data, which were used to decipher individual microbiological reaction mechanisms.
Chemical, microbiological, and in situ test methods for biogenic sulfuric acid corrosion of concrete
Cement and Concrete Research, 2000
Biogenic sulfuric acid corrosion is often a problem in sewer environment; it can lead to a fast degradation of the concrete structures. Since the involvement of bacteria in the corrosion process was discovered, considerable microbiological research has been devoted to the understanding of the corrosive process. Mechanical engineers have focused on experiments comparing the resistance of several concrete mixes against biogenic sulfuric acid corrosion. Because of a lack of standardised methods, different test methods have been used, and various parameters have been modified to evaluate the resistance of the materials. The research done on sulfuric acid corrosion of concrete can roughly be divided in three groups: chemical tests, microbial simulation tests, and exposure tests in situ. In this article, an overview of the recent developments in the test methods for biogenic sulfuric acid corrosion and the obtained results are presented. Possible differences between biogenic sulfuric acid corrosion and chemical sulfuric acid corrosion are delineated. D
Biogenic sulfuric acid attack on different types of commercially produced concrete sewer pipes
Cement and Concrete Research, 2010
Laboratory experiments were conducted to compare the degradation of low and high quality concrete under conditions simulating sewer pipes with and without bacteria. Small concrete samples were exposed to hydrogen sulfide, multiple species of bacteria found in corroding sewer pipes and artificial wastewater. Experiments without bacteria were used as controls. The corrosion rates of the concrete samples exposed to bacteria over 227 days were 0.08 mm/yr (millimeters per year) for the concrete from a domestic manufacturer with moderate strength and a lower water-cement ratio (Low-w/c) versus 0.208 mm/yr for the concrete samples from a foreign country with low strength and a higher water-cement ratio (High-w/c). The (Low-w/c) concrete was more resistant to the biodegradation even though a lower pH was attained for its bioactive systems. Experiments showed the influence of biogenic sulfuric acid production on short term corrosion rates.
Microbiologically induced corrosion (MIC) of concrete sanitary sewers is a common problem that demands a large rehabilitation investment every year. MIC is the result of dilute sulfuric acid (H2SO4) dissolving the cement matrix. The acid is produced by a complex series of chemical and biochemical reactions. Hydrogen sulfide (H2S) is produced by sulfur reducing bacteria (SRB) in the liquid phase, and then in time, this gas is converted by sulfur oxidizing bacteria (SOB) into H2SO4. The last conversion occurs above the liquid level under aerobic condition. The objectives of this paper are (1) to present a literature review of MIC processes and factors influencing them, and (2) to discuss control mechanisms and authors' experience on development over years in understanding MIC of concrete (MICC) in sanitary sewerage environment (SSE). Published papers were identified that reported MICC in SSE for the past 30 years. The literature review and authors' on-site and laboratory investigations suggest that MIC of concrete is a complex process that involves varied surface interactions. The addition of liquid antimicrobial additive as per standard procedure shows resistance of concrete to MIC and its direct relation with mixing time of admixture. Many empirical inputs like corrosion areas, corrosion rates, impact of cement and aggregate types varying with installation and repair of sewer structures are identified. The review results show variation in corrosion rates and other empirical inputs obtained on-site and through laboratory studies due to different testing procedures. Further research is needed to establish quantitative relations between empirical inputs related to MICC in SSE. Identification and development of more effective coatings and safe antibacterial agents will help inhibit colonization of SOB over exposed sewers and better understand environmental microbiology.
Polish Journal of Environmental Studies
External sulfate attack is detected on concrete construction exposed to soils, groundwater, seawater, or wastewater, and leads to serious damage to concrete elements. This paper describes an investigation of acidic corrosion caused by artificial sulphuric acid and biogenic sulphuric acid. The concrete prisms prepared from concrete-containing sulfate-resisting cement were exposed to an acid environment of different origin over a period of 3 months. The concentration of basic chemical elements such as calcium, silicon, iron, and aluminium were measured in liquid phases. Correlation analysis was used to evaluate dependencies and trends of leached-out amounts in these concentrations. Based on correlation coefficient, the intensity of dependency of the leaching trend was determined. A higher aggressiveness of sulfuric acid produced by sulfur-oxidizing bacteria was confirmed in terms of main concrete components' leaching.
Cement and Concrete Research, 2004
New equipment and procedures for chemical and microbiological tests, simulating biogenic sulfuric acid corrosion in sewerage systems, are presented. Subsequent steps of immersion and drying, combined with mechanical abrasion, were applied to simulate events occurring in sewer systems. Both chemical and microbiological tests showed that the aggregate type had the largest effect on degradation. Concrete with limestone aggregates showed a smaller degradation depth than did the concrete with inert aggregates. The limestone aggregates locally created a buffering environment, protecting the cement paste. This was confirmed by microscopic analysis of the eroded surfaces. The production method of concrete pipes influenced durability through its effect on W/C ratio and water absorption values. In the microbiological tests, HSR Portland cement concrete performed slightly better than did the slag cement concrete. A possible explanation can be a more rapid colonisation by microorganisms of the surface of slag cement samples. A new method for degradation prediction was suggested based on the parameters alkalinity and water absorption (as a measure for concrete porosity).