Instrumental analysis of microbiologically influenced corrosion

Appropriate application of techniques for detection andmonitoring of microbiologically influenced corrosion isessential for understanding the mechanistic nature of theinteractions and for obtaining control methods. This paperreviews techniques and methods applied tomicrobiologically influenced corrosion in recent years.The techniques presented in this paper includeelectrochemical noise measurement, concentric electrodes,scanning vibrating electrode mapping, electrochemicalimpedance spectroscopy, atomic force microscopy,confocal laser microscopy, Fourier transform infraredspectroscopy, x-ray photoelectron spectroscopy, Augerelectron spectroscopy, extended x-ray absorption finestructure and utilization of piezoelectric materials. Thesetechniques are reviewed regarding the heterogeneouscharacteristics of microbial consortia and their possibleinfluences on metal substrata. We hope this review willmotivate application and combination of new techniquesfor practical detection and on-line monitoring of theimpact of biofilms on engineering alloys.     

The role of biomineralization in microbiologically influenced corrosion

Synthetic iron oxides (goethite, -FeO·OH; hematite, Fe₂O₃; and ferrihydrite, Fe(OH)₃) were used as model compounds to simulate the mineralogy of surface films on carbon steel. Dissolution of these oxides exposed to pure cultures of the metal-reducing bacterium, Shewanella putrefaciens, was followed by direct atomic absorption spectroscopy measurement of ferrous iron coupled with microscopic analyses using confocal laser scanning and environmental scanning electron microscopies. During an 8-day exposure the organism colonized mineral surfaces and reduced solid ferric oxides to soluble ferrous ions. Elemental composition, as monitored by energy dispersive x-ray spectroscopy, indicated mineral replacement reactions with both ferrihydrite and goethite as iron reduction occurred. When carbon steel electrodes were exposed to S. putrefaciens, microbiologically influenced corrosion was demonstrated electrochemically and microscopically.     

A review: microbiologically influenced corrosion and the effect of cathodic polarization on typical bacteria

Microbiologically influenced corrosion is a serious type of corrosion as approximately 20% of the total economic losses. Sulfate reducing bacteria and Iron oxidizing bacteria are one of the typical representatives of the anaerobic and aerobic bacteria, which are ubiquitous in natural environments and corrode steel structures. Cathodic polarization has been recognized as an effective method for preventing steels from microbial corrosion. Although cathodic polarization method has been widely studied, the specific properties of cathodic current that influences the bacterial removal and inactivation remained largely unclear. This review is to show the main effects of Sulfate reducing bacteria and Iron oxidizing bacteria on metal decay as well as the inhibition mechanism of cathodic polarization in the study of bio-corrosion.     

Experimental investigation of microbiologically influenced corrosion of selected steels in sugarcane juice environment

In the current study, ferritic stainless grades AISI 439 and AISI 444 were investigated as possible construction materials for machinery and equipment in the cane-sugar industry. Their performance in corrosive cane-sugar juice environment was compared with the presently used low carbon steel AISI 1010 and austenitic stainless steel AISI 304. The Tafel plot electrochemical technique was used to evaluate general corrosion performance. Microbiologically influenced corrosion (MIC) behaviour in sugarcane juice environment was studied. Four microbial colonies were isolated from the biofilms on the metal coupon surfaces on the basis of their different morphology. These were characterized as Brevibacillus parabrevis, Bacillus azotoformans, Paenibacillus lautus and Micrococcus sp. The results of SEM micrographs showed that AISI 439 and AISI 304 grades had suffered maximum localized corrosion. MIC investigations revealed that AISI 444 steel had the best corrosion resistance among the tested materials. However from the Tafel plots it was evident that AISI 1010 had the least corrosion resistance and AISI 439 the best corrosion resistance.     

An impedance study on admiralty brass dezincification originated by microbiologically influenced corrosion

In this article we describe a field study of biofouling and microbiologically influenced corrosion (MIC) of admiralty brass heat exchanger tubes in contact with running fresh water on the river Tagus close to Almaraz nuclear power plant in Spain. Dezincification originated by biofouling and MIC was studied using impedance, polarization resistance, gravimetric, scanning electron microscopy (SEM), and X-ray diffraction (XRD) measurements. Close correlation was observed between the biofilms formed and the corrosion process (dezincification) using the different experimental techniques. Impedance data showed a capacitive behavior including two time constants. Kramers-Kronig (KK) transforms were used to validate impedance data. The admiralty tubes' impedance data satisfied the KK relations.     

Influence of carbon steel grade on the initial attachment of bacteria and microbiologically influenced corrosion

The influence of the composition and microstructure of different carbon steel grades on the initial attachment (≤ 60 min) of Escherichia coli and subsequent longer term (28 days) corrosion was investigated. The initial bacterial attachment increased with time on all grades of carbon steel. However, the rate and magnitude of bacterial attachment varied on the different steel grades and was significantly less on the steels with a higher pearlite phase content. The observed variations in the number of bacterial cells attached across different steel grades were significantly reduced by applying a fixed potential to the steel samples. Longer term immersion studies showed similar levels of biofilm formation on the surface of the different grades of carbon steel. The measured corrosion rates were significantly higher in biotic conditions compared to abiotic conditions and were found to be positively correlated with the pearlite phase content of the different grades of carbon steel coupons.     

Influence of an oil soluble inhibitor on microbiologically influenced corrosion in a diesel transporting pipeline

Abstract

Microbial degradation of the oil soluble corrosion inhibitor (OSCI) Baker NC 351 contributed to a decrease in inhibitor efficiency. Corrosion inhibition efficiency was studied by the rotating cage and flow loop methods. The nature of the biodegradation of the corrosion inhibitor was also analysed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. The influence of bacterial activity on the degradation of the corrosion inhibitor and its influence on corrosion of API 5LX were evaluated using a weight loss technique and impedance studies. Serratia marcescens ACE2 and Bacillus cereus ACE4 can degrade aromatic and aliphatic hydrocarbons present in the corrosion inhibitor. The present study also discusses the demerits of the oil soluble corrosion inhibitors used in petroleum product pipeline.     

Influence of an oil soluble inhibitor on microbiologically influenced corrosion in a diesel transporting pipeline

Microbial degradation of the oil soluble corrosion inhibitor (OSCI) Baker NC 351 contributed to a decrease in inhibitor efficiency. Corrosion inhibition efficiency was studied by the rotating cage and flow loop methods. The nature of the biodegradation of the corrosion inhibitor was also analysed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. The influence of bacterial activity on the degradation of the corrosion inhibitor and its influence on corrosion of API 5LX were evaluated using a weight loss technique and impedance studies. Serratia marcescens ACE2 and Bacillus cereus ACE4 can degrade aromatic and aliphatic hydrocarbons present in the corrosion inhibitor. The present study also discusses the demerits of the oil soluble corrosion inhibitors used in petroleum product pipeline.     

Proteins identified through predictive metagenomics as potential biomarkers for the detection of microbiologically influenced corrosion

The unpredictability of microbial growth and subsequent localized corrosion of steel can cause significant cost for the oil and gas industry, due to production downtime, repair, and replacement. Despite a long tradition of academic research and industrial experience, microbial corrosion is not yet fully understood and thus not effectively controlled. In particular, biomarkers suitable for diagnosing microbial corrosion which abstain from the detection of the classic signatures of sulfate-reducing bacteria are urgently required. In this study, a natural microbial community was enriched anaerobically with carbon steel coupons and in the presence of a variety of physical and chemical conditions. With the characterization of the microbiome and of its functional properties inferred through predictive metagenomics, a series of proteins were identified as biomarkers in the water phase that could be correlated directly to corrosion. This study provides an opportunity for the further development of a protein-based biomarker approach for effective and reliable microbial corrosion detection and monitoring in the field.     

Studies on microbiologically influenced corrosion of SS304 by a novel manganese oxidizer, Bacillus flexus

A manganese oxidizing bacterium was isolated from the surface of steel scraps and biochemical tests and 16S rRNA sequencing analysis confirmed the isolate as Bacillus flexus. Potentiodynamic polarization curves showed ennoblement of open circuit potential, increased passive current, a lowering of breakdown potential, active re-passivation potential and enhanced cathodic current in the presence of B. flexus. Adhesion studies with B. flexus on SS304 specimens with different surface treatments demonstrated decreased adhesion on passivated and FeCl(3) treated specimens due to the removal of MnS inclusions. The present study provides evidence that surface treatment of stainless steels can reduce adhesion of this manganese oxidizing bacterium and decrease the probability of microbiologically influenced corrosion.     

Studies on microbiologically influenced corrosion of SS304 by a novel manganese oxidizer,Bacillus flexus

A manganese oxidizing bacterium was isolated from the surface of steel scraps and biochemical tests and 16S rRNA sequencing analysis confirmed the isolate as Bacillus flexus. Potentiodynamic polarization curves showed ennoblement of open circuit potential, increased passive current, a lowering of breakdown potential, active re-passivation potential and enhanced cathodic current in the presence of B. flexus. Adhesion studies with B. flexus on SS304 specimens with different surface treatments demonstrated decreased adhesion on passivated and FeCl₃ treated specimens due to the removal of MnS inclusions. The present study provides evidence that surface treatment of stainless steels can reduce adhesion of this manganese oxidizing bacterium and decrease the probability of microbiologically influenced corrosion.     

Advances in detection of microbiologically induced corrosion

A number of recently developed techniques which may be used for rapid quantification of total microbial activity or of specific microorganisms involved in corrosion are reviewed. These include viable counts using dip slides, microscope methods (epifluorescence), analysis of cell components (ATP, ergosterol, phospholipids), immunological methods (fluorescent antibody staining, ELISA), activity measurements (respiration, esterases, sulphate reduction) and the use of gene probes. The methods are discussed with reference to their simplicity, sensitivity, economics and applications.     

Microbiologically influenced corrosion in petroleum product pipelines--a review

Microbiologically influenced corrosion is responsible for most of the internal corrosion problems in oil transportation pipelines and storage tanks. One problematic area in treating gas lines is the occurrence of the stratification of water in the line. Under these conditions, corrosion inhibitors do not come into contact properly and oil and inhibitors undergo degradation. The role of bacteria on oil degradation, the consequences of oil degradation in fuel systems and its influence on corrosion have been explained in detail. Besides, factors influencing on degradation of oil and corrosion inhibitors have also been discussed. Mechanism of microbiologically influenced corrosion in oil pipeline has been explained. Many of the misapplication of biocides/inhibitors occur mainly because the characteristics of biocides/inhibitors are not considered before use in pipeline industry. List of biocides and monitoring programme have been collected from literature and presented.     

Critical review: Microbially influenced corrosion of buried carbon steel pipes

External corrosion of buried carbon steel pipes is a problem of global proportions, affecting a wide range of industries and services. Many factors affect corrosion rates. Biofilms may secrete enzymes and compounds that attack metal, alter local acidity and create differential aeration and galvanic cells. An important consideration is that biofilm metabolisms and enzymatic reactions are constantly in flux, altering the impact of microorganisms on corrosion rates, and thermodynamic equilibrium is not reached. Recent research demonstrates that some anaerobic microorganisms catalyse the oxidation of metallic iron and directly consume the electrons, with serious consequences for corrosion. This review examines relationships between soil characteristics, microbiology and corrosion processes, focussing on the impacts of microorganisms on external corrosion of buried carbon steel pipes. Techniques for improving the understanding of microbially influenced corrosion are considered and critiqued, with the aim of assisting those who work in the area of corrosion mitigation.     

Microbially influenced corrosion of glass

Microbially influenced corrosion of glass and countermeasures were studied by literature research and by an investigation of contaminated glass samples. Such corrosion is often linked to the growth of fungi. It is assumed that glass composition is not the decisive factor in biogenic contamination, but can encourage or retard the microbial activity significantly. It is suggested that a biochemically initiated ion-exchange reaction is most important for corrosion of glass exposed to the atmosphere. Future work will emphasize the biotechnological applications in the recovery of heavy metals from special glasses. Received: 26 September 1996 / Received revision: 17 December 1996 / Accepted: 17 December 1996     

Conservation strategies to mitigate impacts from climate change in Amazonia

Protected area systems and conservation corridors can help mitigate the impacts of climate change on Amazonian biodiversity. We propose conservation design criteria that will help species survive in situ or adjust range distributions in response to increased drought. The first priority is to protect the western Amazon, identified as the 'Core Amazon', due to stable rainfall regimes and macro-ecological phenomena that have led to the evolution of high levels of biodiversity. Ecotones can buffer the impact from climate change because populations are genetically adapted to climate extremes, particularly seasonality, because high levels of habitat diversity are associated with edaphic variability. Future climatic tension zones should be surveyed for geomorphological features that capture rain or conserve soil moisture to identify potential refugia for humid forest species. Conservation corridors should span environmental gradients to ensure that species can shift range distributions. Riparian corridors provide protection to both terrestrial and aquatic ecosystems. Multiple potential altitudinal corridors exist in the Andes, but natural and anthropogenic bottlenecks will constrain the ability of species to shift their ranges and adapt to climate change. Planned infrastructure investments are a serious threat to the potential to consolidate corridors over the short and medium term.     

Microbiologically influenced corrosion: looking to the future.

This review discusses the state-of-the-art of research into biocorrosion and the biofouling of metals and alloys of industrial usage. The key concepts needed to understand the main effects of microorganisms on metal decay, and current trends in monitoring and control strategies to mitigate the deleterious effects of biocorrosion and biofouling are also described. Several relevant cases of biocorrosion studied by our research group are provided as examples: (i) biocorrosion of aluminum and its alloys by fungal contaminants of jet fuels; (ii) sulfate-reducing bacteria (SRB)-induced corrosion of steel; (iii) biocorrosion and biofouling interactions in the marine environment; (iv) monitoring strategies for assessing biocorrosion in industrial water systems; (v) microbial inhibition of corrosion; (vi) use and limitations of electrochemical techniques for evaluating biocorrosion effects. Future prospects in the field are described with respect to the potential of innovative techniques in microscopy (environmental scanning electron microscopy, confocal scanning laser microscopy, atomic force microscopy), new spectroscopic techniques for the study of corrosion products and biofilms (energy dispersion X-ray analysis, X-ray photoelectron spectroscopy, electron microprobe analysis) and electrochemistry (electrochemical impedance spectroscopy, electrochemical noise analysis).     

Biological sources and sinks of nitrous oxide and strategies to mitigate emissions

Nitrous oxide (N(2)O) is a powerful atmospheric greenhouse gas and cause of ozone layer depletion. Global emissions continue to rise. More than two-thirds of these emissions arise from bacterial and fungal denitrification and nitrification processes in soils, largely as a result of the application of nitrogenous fertilizers. This article summarizes the outcomes of an interdisciplinary meeting, 'Nitrous oxide (N(2)O) the forgotten greenhouse gas', held at the Kavli Royal Society International Centre, from 23 to 24 May 2011. It provides an introduction and background to the nature of the problem, and summarizes the conclusions reached regarding the biological sources and sinks of N(2)O in oceans, soils and wastewaters, and discusses the genetic regulation and molecular details of the enzymes responsible. Techniques for providing global and local N(2)O budgets are discussed. The findings of the meeting are drawn together in a review of strategies for mitigating N(2)O emissions, under three headings, namely: (i) managing soil chemistry and microbiology, (ii) engineering crop plants to fix nitrogen, and (iii) sustainable agricultural intensification.     

Evaluation of chemical treatments to mitigate or eradicate Gnathia maxillaris infestations

The eradication of the haematophagous isopod ectoparasite Gnathia maxillaris was not achieved after several years of physical elimination of larvae by filtration and chemical treatment with trichlorfon in a captive marine fish population in exhibition aquaria. In this study, different in vitro laboratory assays were performed to find effective alternative anti‐parasitic treatments to trichlorfon (lufenuron, emamectin benzoate, cypermethrin and abamectin). The lethal concentration 50 (LC50) values at 96 hr were calculated for each compound using both larval stages (zuphea and praniza); morphological deformities generated throughout the life cycle, reduction in egg laying and survival of adult forms were also determined. Abamectin, cypermethrin and emamectin benzoate proved effective at limiting further Gnathia maxillaris development, but their efficacy at eradicating an infestation in large tanks was not supported by laboratory assays. However, the use of lufenuron proved to be a good substitute for trichlorfon when treating this type of infestation in large‐volume tanks (LC50 55.8 mg m^?3 for praniza). Routine lufenuron treatment once a month via an oral dose at 10 mg kg^?1 body weight eradicated G. maxillaris from the exhibition aquaria.     

最佳管理措施评估方法研究进展

针对流域非点源污染的关键源区,进行最佳管理措施(BMPs)的配置,是非点源污染控制的有效途径.污染削减效率的准确识别对于BMPs在目标流域内的有效实施具有非常重要的意义.通过综合对比和分析实地监测、养分平衡、风险评估以及模型模拟等四类最佳管理措施评估方法的有效性、特点、适用条件及其局限性,得出以下结论:养分平衡法较为简便且易于使用,相较于其他方法,所需时间短且又可以消除评估效果的滞后效应,但对污染物削减的时间效应和传输过程影响考虑较少.风险评估和模型模拟方法可以更好地应对不同时空尺度下削减措施效率的评估,但需要大量实测数据的支持,同时模型模拟中普遍存在的时空不确定性影响很难消除.由于各种评估方法都有一定的适用条件,单一方法难以有效地完成评估目标,需要综合应用各类方法,才能最大程度地发挥这些方法的潜在功能和有效性,进而实现BMPs措施使用的成本-效益目标.