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1
Enning, Dennis, and Julia Garrelfs. "Corrosion of Iron by Sulfate-Reducing Bacteria: New Views of an Old Problem." Applied and Environmental Microbiology 80, no. 4 (December 6, 2013): 1226–36. http://dx.doi.org/10.1128/aem.02848-13.
Повний текст джерелаАнотація:
ABSTRACTAbout a century ago, researchers first recognized a connection between the activity of environmental microorganisms and cases of anaerobic iron corrosion. Since then, such microbially influenced corrosion (MIC) has gained prominence and its technical and economic implications are now widely recognized. Under anoxic conditions (e.g., in oil and gas pipelines), sulfate-reducing bacteria (SRB) are commonly considered the main culprits of MIC. This perception largely stems from three recurrent observations. First, anoxic sulfate-rich environments (e.g., anoxic seawater) are particularly corrosive. Second, SRB and their characteristic corrosion product iron sulfide are ubiquitously associated with anaerobic corrosion damage, and third, no other physiological group produces comparably severe corrosion damage in laboratory-grown pure cultures. However, there remain many open questions as to the underlying mechanisms and their relative contributions to corrosion. On the one hand, SRB damage iron constructions indirectly through a corrosive chemical agent, hydrogen sulfide, formed by the organisms as a dissimilatory product from sulfate reduction with organic compounds or hydrogen (“chemical microbially influenced corrosion”; CMIC). On the other hand, certain SRB can also attack iron via withdrawal of electrons (“electrical microbially influenced corrosion”; EMIC),viz., directly by metabolic coupling. Corrosion of iron by SRB is typically associated with the formation of iron sulfides (FeS) which, paradoxically, may reduce corrosion in some cases while they increase it in others. This brief review traces the historical twists in the perception of SRB-induced corrosion, considering the presently most plausible explanations as well as possible early misconceptions in the understanding of severe corrosion in anoxic, sulfate-rich environments.
2
Nicoletti, Danika, Mohita Sharma, and Lisa M. Gieg. "Assessing Microbial Corrosion Risk on Offshore Crude Oil Production Topsides under Conditions of Nitrate and Nitrite Treatment for Souring." Microorganisms 10, no. 5 (April 29, 2022): 932. http://dx.doi.org/10.3390/microorganisms10050932.
Повний текст джерелаАнотація:
Oilfield souring is a detrimental effect caused by sulfate-reducing microorganisms that reduce sulfate to sulfide during their respiration process. Nitrate or nitrite can be used to mitigate souring, but may also impart a corrosion risk. Produced fluids sampled from the topside infrastructure of two floating, production, storage, and offloading (FPSO) vessels (Platform A and Platform B) were assessed for microbial corrosion under nitrate and nitrite breakthrough conditions using microcosm tests incubated at 54 °C. Microbial community compositions on each individual FPSO were similar, while those between the two FPSO vessels differed. Platform B microbial communities responded as expected to nitrate breakthrough conditions, where nitrate-reducing activity was enhanced and sulfate reduction was inhibited. In contrast, nitrate treatments of Platform A microbial communities were not as effective in preventing sulfide production. Nitrite breakthrough conditions had the strongest sulfate reduction inhibition in samples from both platforms, but exhibited the highest pitting density. Live experimental replicates with no nitrate or nitrite additive yielded the highest general corrosion rates in the study (up to 0.48 mm/year), while nitrate- or nitrite-treated fluids revealed general corrosion rates that are considered low or moderate (<0.12 mm/year). Overall, the results of this study provide a description of nitrogen- and sulfur-based microbial activities under thermophilic conditions, and their risk for MIC that can occur along fluid processing lines on FPSO topsides that process fluids during offshore oil production operations.
3
Vyšvařil, Martin, and Markéta Rovnaníková. "Study of Fine-Grained Composites Exposed to Sulfuric Acid and Sodium Sulfate." Applied Mechanics and Materials 827 (February 2016): 275–78. http://dx.doi.org/10.4028/www.scientific.net/amm.827.275.
Повний текст джерелаАнотація:
The degradation of concrete due to ingress of sulfate ions from the environment plays an important role in the durability of concrete constructions, especially in sewage collection systems where concrete sewer pipes are exposed to sulfates from waste water and from biogenic activity of bacteria. During this process the pH of the surface of concrete sewer pipes is reduced and it may lead to the steel depassivation and results in the corrosion of steel reinforcement. Damage due to sulfate interaction can result in the cracking and softening, with loss of strength of concrete. This paper is focused on the sulfate attack on fine-grained concrete where the effect of one-year contact of 0.5% H2SO4, and 5% Na2SO4 on changes of pH and content of sulfates in 7 types of concrete has been analyzed. It was found that after one year of sulfate attack on concrete, significant growth of content of sulfates is observed in the lowermost layer of the samples. Samples treated by 5% Na2SO4 contain slightly more sulfates in the upper layers than samples treated by sulfuric acid. The reduction in pH of aqueous leaches occurred in all layers of the samples. However, even in the lower layers of the samples, the reduction of pH below 9.5 did not turn up (except for SRS sample), and thus the conditions for the depassivation of reinforcement were not met.
4
Boontian, Nittaya. "Effect of Zero Valent Iron (ZVI) in Wastewater Treatment: A Review." Applied Mechanics and Materials 775 (July 2015): 180–84. http://dx.doi.org/10.4028/www.scientific.net/amm.775.180.
Повний текст джерелаАнотація:
Cathodic hydrogen was produced in the presence of anaerobic zero valent iron (ZVI) corrosion by water. It can enhance microbial denitrification to convert nitrate to N2O and N2. Autotrophic denitrifying growth on ZVI can enhance nitrate removal. Results showed that by increasing nitrate removal rates, innocuous gases (N2O and N2) are produced rather than ammonium. Using steel wool with a small specific surface area instead of powdered ZVI, pH was not significantly increased. Little pH change was caused by corrosion. This is a positive condition for autotrophic denitrifying bacteria. ZVI was used in permeable reactive barriers (PRBs) process under anaerobic conditions. It used sulfate reducing bacteria for immobilization of heavy metals. In fermentation, methanogenesis and sulfate reduction was complete after adding ZVI to mixed anaerobic cultures. It was found that methane production increased and sulfate was reduced. This was due to readily utilizable ZVI which served as a slow-release electron donor for methanogenesis and sulfate reduction. ZVI has potential as a useful material in bioremediation.
5
Choung, Y. K., and S. J. Jeon. "Phosphorus removal in domestic wastewater using anaerobic fixed beds packied with iron contactors." Water Science and Technology 41, no. 1 (January 1, 2000): 241–44. http://dx.doi.org/10.2166/wst.2000.0035.
Повний текст джерелаАнотація:
The objective of this study is to develop an alternative phosphorus removal system for small-scale plants disposing domestic wastewater. In order to promote anaerobic microbial corrosion by sulfate reducing bacteria (SRB), a bench-scale upflow anaerobic fixed bed (UAFB) packed with iron contactors was installed, and operated to investigate the treatment characteristics of domestic wastewater from an apartment complex. It was found that there is a linear relationship between anaerobic corrosion and sulfate reduction by SRB within the range of operational conditions. As the results of introducing the UAFBs prior to an anoxic/oxic process, phosphorus removal efficiencies were enhanced with no adverse effects on nitrification and denitrification.
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Fang, Xiao Jun, Li Liu, Zhi Gang Yang, and Yong Qiang Zhang. "Preparation and Performance Evaluation of a Novel Bactericide for Sulfate Reducing Bacteria." Materials Science Forum 1035 (June 22, 2021): 624–29. http://dx.doi.org/10.4028/www.scientific.net/msf.1035.624.
Повний текст джерелаАнотація:
The sulfate reducing bacteria (SRB) bactericide was synthesized using KNO3, isothiazolinone, quaternary ammonium salt, and additives as main components, and the optimal ratio and critical concentration of the bactericide were determined. Weight loss method, potentiodynamic polarization curve, compatibility study were used to investigate the changes of corrosion rate and corrosion current density and compatibility after adding the bactericide. The results showed that the optimal formula ratio of the bactericide was: KNO3: isothiazolinone: quaternary ammonium salt: additive is 20:1:2:3, and the critical concentration of the bactericide was 50 mg/L. The addition of bactericides reduced the corrosion rate of pipes by 67% to 88%, and the electrochemical corrosion current density of pipes was significantly reduced, indicating that the presence of bactericides under the given media conditions significantly slowed down the corrosion process of metals. The bactericide was used in conjunction with commonly used oilfield chemicals such as corrosion inhibitors, scale inhibitors, flocculants, without obvious changes in appearance, no reduction in efficacy. Therefore, it may be concluded that the bactericide has good compatibility.
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Ehsani, Ali, Mohammad Ghasem Mahjani, Maryam Nasseri, and Majid Jafarian. "Influence of electrosynthesis conditions and Al2O3 nanoparticles on corrosion protection effect of polypyrrole films." Anti-Corrosion Methods and Materials 61, no. 3 (April 29, 2014): 146–52. http://dx.doi.org/10.1108/acmm-07-2012-1193.
Повний текст джерелаАнотація:
Purpose – The purpose of this paper was to investigate the anti-corrosion behavior of polypyrrole (PPy) films in different states and presence of alumina nanoparticles synthesized by galvanostatic electropolymerization on stainless steel (SS) electrodes in an artificial seawater solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Design/methodology/approach – The electrochemical measurements were used to examine the effects of PPy and its nanocomposite on the corrosion behavior of SS type 316L in artificial seawater. A standard electrochemical cell with three electrodes was used for the measurements. The electrochemical response of the coated electrodes in the doped and the undoped state was compared with that of a bare electrode. Corrosion rate information was obtained by the Tafel extrapolation method, where the intersection point of a cathodic and an anodic polarization curve provides both the corrosion potential and the corrosion current. EIS measurements confirmed the potentiodynamic and open circuit potential (OCP) results. The microstructure of the obtained films was investigated by scanning electron microscopy. Findings – The results showed that the coated polymer films shifted the electrode potential toward more positive potentials, but this shift did not lead to passivation. However, a notable synergy was observed between PPy undoped film, oxygen reduction and iron dissolution. The potential of the SS remained in the active dissolution region, and it was not possible to produce a passive oxide layer in this region. PPy separates the metal dissolution process from the oxygen reduction process. This would prevent the local pH increase at the metal surface and subsequent delamination. The polarization curves, EOCP and impedance measurements showed that PPy undoped/Al2O3 layers show promise as good candidates for the corrosion protection of reactive metals. Originality/value – This paper presents that electrodes coated with undoped PPy synthesized in the presence of dodecyl sulfate anions and Al2O3 nanoparticles offered a noticeable enhancement of protection against corrosion processes.
8
García-Ávila, Fernando, Lía Ramos-Fernández, and César Zhindón-Arévalo. "Estimation of corrosive and scaling trend in drinking water systems in the city of Azogues, Ecuador." Ambiente e Agua - An Interdisciplinary Journal of Applied Science 13, no. 5 (October 1, 2018): 1. http://dx.doi.org/10.4136/ambi-agua.2237.
Повний текст джерелаАнотація:
The quality of drinking water flowing in a distribution network can possess corrosive characteristics that may cause the material degradation of pipes and accessories. This problem can result in reduction of the service life of pipes and create a major public health problem. The agreement between the physical-chemical water quality analysis and national standards are not enough to confirm the balance of the water quality in terms of corrosion. In order to predict pipe corrosion in water distribution system networks, the corrosive trend was evaluated using the Langelier (LSI), Ryznar (RSI), and Larson-Skold (LRI) indexes based on measurements of pH, temperature, total dissolved solids, alkalinity, calcium hardness, sulfate and chloride. This study was setup with 180 samples collected in six zones of the distribution network, from July to December of 2017, according to the standard methods for the analysis of drinking water. The results indicate a variation of the LSI from -1.22 to -1.68; RSI from 9.75 to 10.52 and LRI from 0.46 to 0.77. A linear model was fitted for each index to predict the corrosion with the water quality conditions of this study case. Therefore, the drinking water of the city of Azogues, Ecuador has a corrosive tendency from significant to severe. Corrosion indices were calculated to provide useful information on the water's corrosiveness. These results indicate the need to constantly monitor the corrosion rate in the distribution network and conduct a laboratory study to adjust effective parameters such as pH, in order to control corrosion.
9
Vossoughi, M., and I. Alemzadeh. "A Study of Microbial Problems and Their Control in the Oilfield Waters." Water Science and Technology 25, no. 3 (February 1, 1992): 263. http://dx.doi.org/10.2166/wst.1992.0102.
Повний текст джерелаАнотація:
Microorganisms present in injection water or other oilfield water may cause corrosion or plugging of lines and reservoir formation rock. It should be pointed out that the mere presence of bacteria or other microorganisms in water does not necessarily mean that they present a problem. Elimination or reduction of bacteria is justified only if it represents an economical solution to a corrosion or plugging problem. This paper is an attempt to report the most important bacteria which grow in oilfield of Ahwaz (Iran), in order to control the action and their growth. Sulfate reducing bacteria (SRB) were the most important and damaging bacteria in this area. They cause corrosion, and the iron sulfide produced as a product of the corrosion reaction is an excellent,plugging material. The bacteria have been isolated from black deep sediments of a river in the neighbourhood of Ahwaz in which the sulfate concentration is high enough to promote the activity of SRB. The strains were first cultivated in anaerobic shakeflasks and progressively adapted to the culture contained carbohydrate and yeast extract as a model for primary experiment. The effect of the pH and temperature on the growth of bacteria under continuous cultivation show that the SRB grow under rather extreme conditions e.g. under pH ranging from 4 to 10, and temperature from 20 to 50°c.
10
Chen, Shi Qiang, Dun Zhang, and Jia Jia Wu. "Influence of Sulfide on Oxygen Reduction Reaction in 3.5% Sodium Chloride Solution." Advanced Materials Research 581-582 (October 2012): 104–7. http://dx.doi.org/10.4028/www.scientific.net/amr.581-582.104.
Повний текст джерелаАнотація:
Different from the corrosion under anaerobic conditions, oxygen (O2) takes part in the cathodic reaction under aerobic conditions. Sulfate-reducing bacteria (SRB) have been regarded for many years as strictly anaerobic bacteria, but recently, they are found to be able to survive in the presence of O2, and how they affect the oxygen reduction reaction (ORR) has not been clear. In this study, the role of sulfide, a key inorganic metabolite of SRB, in ORR has been investigated on Q235 carbon steel electrode with cyclic voltammetry and electrochemical impedance spectroscopy. Three cathodic processes are recorded on cyclic voltammograms in O2-saturated 3.5% NaCl solution: ORR, iron oxides reduction and hydrogen evolution. The peak current of ORR decreases with the introduction of sulfide, and finally vanishes when the sulfide concentration is more than 0.5 mM. EIS reveals that sulfide leads to the disappearance of the feature of semi-infinite diffusion of ORR and the fitting results demonstrate that charge transfer resistance increases with increasing sulfide concentration. Therefore sulfide hinders the cathodic reduction of O2on Q235 carbon steel in 3.5% NaCl solution.
11
Nicomrat, Duongruitai. "Decline in Sulfate Reducing Bacterial Consortia by the Sulfur Oxidizing Bacterial Activity." Applied Mechanics and Materials 866 (June 2017): 140–43. http://dx.doi.org/10.4028/www.scientific.net/amm.866.140.
Повний текст джерелаАнотація:
In anaerobic environment, dominant sulfate reducing bacteria (SRB) consortia are found to cause many serious problems to the oil such as sour oil, hydrogen sulfide (H2S), and metal corrosion. They are obligatory anaerobes using sulfate, thiosulfate and sulfites as final electron acceptors and use organic acids or alcohols as a carbon source. In the aerobic system, other dominant niches are sulfur-oxidizing bacteria (SOB) playing role in biological oxidation of hydrogen sulfide. These SOB convert H2S into elemental sulfur (S0) by partial oxidation. Since the levels of reduction and oxidation are dependent on the oxygen concentration. In the condition of limited oxygen, sulfate generated by SOB can also be contributed to the reduction of oxygen which encourages SRB proliferation in anaerobic environment. In this research, we were interested to manage the conditions to control the dominant niches by management of oxygen levels. In the experiment, the concentration of sulfate concentration, acidity, sulfide were determined to understand the microbial activity. The results showed after cocultures of SRB and SOB niches in the present of oxygen, the activity of SRB was prevented since a decrease in H2S product but an increase in sulfate concentration were observed. This revealed a promising niches of SOB isolates in the presence of oxygen and active in high sulfide removal. These data indicated the situation suitable for either SOB or SRB community is dependent on oxygen concentration. The management of SOB community can be used as an alternative method to remove contaminating H2S from the system.
12
Pedersen, Karsten. "Investigations of subterranean bacteria in deep crystalline bedrock and their importance for the disposal of nuclear waste." Canadian Journal of Microbiology 42, no. 4 (April 1, 1996): 382–91. http://dx.doi.org/10.1139/m96-054.
Повний текст джерелаАнотація:
The diversity and distribution of bacteria in subterranean environments have been found to be extensive and to depend on the prevailing environmental conditions. In 1987, microbiology became a part of the Swedish scientific program for the safe disposal of high level nuclear waste (HLW). The goal of the microbiology program is to understand how subterranean bacteria will interact with the performance of a future HLW repository. It concerns several major processes that directly or indirectly may exert influence on waste canister corrosion and the mobility of radionuclides. Uptake and transport of radionuclides by bacteria seem to be negligible components for radionuclide migration, but the effect from bacterial production of complexing agent remains to be evaluated. Also, bacterial production and consumption of gases will influence radionuclide transport due to gas bubbles. Many important radionuclides are immobile at reduced conditions and mobile at oxidized conditions. Bacterial activity can, therefore, indirectly decrease the mobility of radionuclides due to consumption of oxygen and the reduction of electron acceptors to species such as ferrous iron and sulfide.Key words: 16S rRNA, diversity, microbial activity, nuclear waste, sulfate reduction.
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Plugge, Caroline M., João A. B. Sousa, Stephan Christel, Mark Dopson, Martijn F. M. Bijmans, Alfons J. M. Stams, and Martijn Diender. "Syngas as Electron Donor for Sulfate and Thiosulfate Reducing Haloalkaliphilic Microorganisms in a Gas-Lift Bioreactor." Microorganisms 8, no. 9 (September 22, 2020): 1451. http://dx.doi.org/10.3390/microorganisms8091451.
Повний текст джерелаАнотація:
Biodesulfurization processes remove toxic and corrosive hydrogen sulfide from gas streams (e.g., natural gas, biogas, or syngas). To improve the efficiency of these processes under haloalkaline conditions, a sulfate and thiosulfate reduction step can be included. The use of H2/CO mixtures (as in syngas) instead of pure H2 was tested to investigate the potential cost reduction of the electron donor required. Syngas is produced in the gas-reforming process and consists mainly of H2, carbon monoxide (CO), and carbon dioxide (CO2). Purification of syngas to obtain pure H2 implies higher costs because of additional post-treatment. Therefore, the use of syngas has merit in the biodesulfurization process. Initially, CO inhibited hydrogen-dependent sulfate reduction. However, after 30 days the biomass was adapted and both H2 and CO were used as electron donors. First, formate was produced, followed by sulfate and thiosulfate reduction, and later in the reactor run acetate and methane were detected. Sulfide production rates with sulfate and thiosulfate after adaptation were comparable with previously described rates with only hydrogen. The addition of CO marginally affected the microbial community in which Tindallia sp. was dominant. Over time, acetate production increased and acetogenesis became the dominant process in the bioreactor. Around 50% of H2/CO was converted to acetate. Acetate supported biomass growth and higher biomass concentrations were reached compared to bioreactors without CO feed. Finally, CO addition resulted in the formation of small, compact microbial aggregates. This suggests that CO or syngas can be used to stimulate aggregation in haloalkaline biodesulfurization systems.
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Akhoondan, M., and A. A. Sagüés. "Comparative Cathodic Behavior of ~9% Cr and Plain Steel Reinforcement in Concrete." Corrosion 68, no. 4 (April 1, 2012): 045003–1. http://dx.doi.org/10.5006/0010-9312-68-4-4.
Повний текст джерелаАнотація:
The extent of the oxygen reduction reaction in concrete was evaluated for ~9% Cr rebar approaching the ASTM A1035 specification and compared to that of conventional carbon steel rebar, at ages of up to ~1 year. Cathodic strength was measured by the cathodic current density developed at −0.35 V vs. copper/copper sulfate (Cu/CuSO4 [CSE]) and −0.40 VCSE in cyclic cathodic potentiodynamic polarization tests, both in the as-received condition with mill scale and with scale removed by glass bead surface blasting. In both conditions the ~9% Cr alloy was a substantially weaker cathode, by a factor of several fold, than carbon steel. Within each material, the surface-blasted condition yielded also much lower cathodic current density than the as-received condition. For a small anode-large cathode system with a given anode polarization function, and no important oxygen reduction concentration polarization, the corrosion current was projected to be significantly lower if the cathodic region were ~9% Cr instead of plain steel rebar with comparable surface condition. There was strong correlation between the charge storage capability of the interface and the extent of cathodic reaction of oxygen. The result cannot be ascribed solely to differences in effective surface area between the different materials and conditions.
15
Abdulina, D. R., L. M. Purish, and G. O. Iutynska. "Specificity of Lectins Labeled with Colloidal Gold to the Exopolymeric Matrix Carbohydrates of the Sulfate-Reducing Bacteria Biofilm Formed on Steel." Mikrobiolohichnyi Zhurnal 82, no. 5 (October 17, 2020): 11–20. http://dx.doi.org/10.15407/microbiolj82.05.011.
Повний текст джерелаАнотація:
The studies of the carbohydrate composition of the sulfate-reducing bacteria (SRB) biofilms formed on the steel surface, which are a factor of microbial corrosion, are significant. Since exopolymers synthesized by bacteria could activate corrosive processes. The aim of the study was to investigate the specificity of commercial lectins, labeled with colloidal gold to carbohydrates in the biofilm exopolymeric matrix produced by the corrosive-relevant SRB strains from man-caused ecotopes. Methods. Microbiological methods (obtaining of the SRB biofilms during cultivation in liquid Postgate B media under microaerophilic conditions), biochemical methods (lectin-binding analysis of 10 commercial lectins, labeled with colloidal gold), transmission electron microscopy using JEM-1400 JEOL. Results. It was shown using transmission electron microscopy that the binding of lectins with carbohydrates in the biofilm of the studied SRB strains occurred directly in the exopolymerіс matrix, as well as on the surfaces of bacterial cells, as seen by the presence of colloidal gold particles. For detection of the neutral carbohydrates (D-glucose and D-mannose) in the biofilm of almost all studied bacterial strains PSA lectin was the most specific. This lectin binding in biofilms of Desulfotomaculum sp. К1/3 and Desulfovibrio sp. 10 strains was higher in 90.8% and 94.4%, respectively, then for ConA lectin. The presence of fucose in the SRB biofilms was detected using LABA lectin, that showed specificity to the biofilm EPS of all the studied strains. LBA lectin was the most specific to N-аcetyl-D-galactosamine for determination of amino sugars in the biofilm. The amount of this lectin binding in D. vulgaris DSM644 biofilm was 30.3, 10.1 and 9.3 times higher than SBA, SNA and PNA lectins, respectively. STA, LVA and WGA lectins were used to detect the N-acetyl-Dglucosamine and sialic acid in the biofilm. WGA lectin showed specificity to N-acetyl-D-glucosamine in the biofilm of all the studied SRB; maximum number of bounded colloidal gold particles (175 particles/μm2) was found in the Desulfotomaculum sp. TC3 biofilm. STA lectin was interacted most actively with N-acetyl-D-glucosamine in Desulfotomaculum sp. TC3 and Desulfomicrobium sp. TC4 biofilms. The number of bounded colloidal gold particles was in 9.2 and 7.4 times higher, respectively, than using LVA lectin. The lowest binding of colloidal gold particles was observed for LVA lectin. Conclusions. It was identified the individual specificity of the 10 commercial lectins to the carbohydrates of biofilm matrix on the steel surface, produced by SRB. It was estimated that lectins with identical carbohydrates specificity had variation in binding to the biofilm carbohydrates of different SRB strains. Establishing of the lectin range selected for each culture lead to the reduction of the scope of studies and labor time in the researching of the peculiarities of exopolymeric matrix composition of biofilms formed by corrosiverelevant SRB.
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Sakit Rasulov, Sakit Rasulov, Elchin Nabiyev Elchin Nabiyev, and Agil Heybatov Agil Heybatov. "ANALYTICAL INVESTIGATION OF THE PROBLEMS OF SALTING AND CORROSION IN OIL AND GAS COMPLEX." PAHTEI-Procedings of Azerbaijan High Technical Educational Institutions 14, no. 03 (March 21, 2022): 101–16. http://dx.doi.org/10.36962/pahtei14032022-101.
Повний текст джерелаАнотація:
One of the problems that cause difficulties in the operation of oilfield equipment and pipeline communications of wells during oil production is asphalt-tar and paraffin (AGPCH). Accumulation of AGPCH in the flow of oilfield equipment reduces the productivity of the system and the coefficient of useful operation of pumping units, as well as shortens the maintenance period. Reduction of pressure at the bottom of the well and, in this regard, violation of thermodynamic balance of the gas-fluid system, intensive gas separation, temperature drop in the reservoir and well body, change of speed of movement of the gas-liquid system and its individual components, composition of hydrocarbons in each phase of the mixture, ratio of the volume of phases and the state of the surface of pipelines. During oil and gas extraction, deposits of inorganic salts are also formed on the inner walls of mining pipelines and equipment. The deposition of salts on the surface of the working bodies of pumps increases their frictionality, causing the dispersion of shafts, workbenches of centrifugal pumps. In oil fields, the deposition of calcium sulfate, calcium and magnesium carbonate and sodium chloride is also characteristic. In aqueous solutions, H2S significantly enhances the penetration of hydrogen into steel compared to general corrosion. The catalytic effect of hydrogen sulfide on hydrogen fragility of metals is given. The presence of CO2 in the liquid and gas produced during oil and gas extraction also speeds up the corrosion process. Therefore, the essence of the corrosion process in the presence of CO2 is shown. Since CO2 is soluble in water and forms weak carbonic acid H2CO3, this acid dissociates into hydrocarbonate and carbonate ions. Formation of CaCO3 in the water phase of oil fields products goes in the presence of hydrocarbonate ions, since the concentration of carbonate ions in them is close to zero. Since one of the products of this reaction is carbonic acid, the deposition of CaCO3 depends on the pressure. Most organic compounds have the ability to slow down corrosion of metals. Organic compounds are inhibitors of mixed action, in other words, they affect the speed of both cathodic and anode processes. Investigation of corrosion sensitivity conditions and mechanism of their formation of equipment and pipe and communication lines in the oil and gas industry makes it possible to develop more effective inhibitors. Keywords: oil emulsion, salting, corrosion, water phase, inhibitory, hydrogen fragility.
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Gao, Shu-Hong, Jun Yuan Ho, Lu Fan, David J. Richardson, Zhiguo Yuan, and Philip L. Bond. "Antimicrobial Effects of Free Nitrous Acid on Desulfovibrio vulgaris: Implications for Sulfide-Induced Corrosion of Concrete." Applied and Environmental Microbiology 82, no. 18 (July 1, 2016): 5563–75. http://dx.doi.org/10.1128/aem.01655-16.
Повний текст джерелаАнотація:
ABSTRACTHydrogen sulfide produced by sulfate-reducing bacteria (SRB) in sewers causes odor problems and asset deterioration due to the sulfide-induced concrete corrosion. Free nitrous acid (FNA) was recently demonstrated as a promising antimicrobial agent to alleviate hydrogen sulfide production in sewers. However, details of the antimicrobial mechanisms of FNA are largely unknown. Here, we report the multiple-targeted antimicrobial effects of FNA on the SRBDesulfovibrio vulgarisHildenborough by determining the growth, physiological, and gene expression responses to FNA exposure. The activities of growth, respiration, and ATP generation were inhibited when exposed to FNA. These changes were reflected in the transcript levels detected during exposure. The removal of FNA was evident by nitrite reduction that likely involved nitrite reductase and the poorly characterized hybrid cluster protein, and the genes coding for these proteins were highly expressed. During FNA exposure, lowered ribosome activity and protein production were detected. Additionally, conditions within the cells were more oxidizing, and there was evidence of oxidative stress. Based on an interpretation of the measured responses, we present a model depicting the antimicrobial effects of FNA onD. vulgaris. These findings provide new insight for understanding the responses ofD. vulgaristo FNA and will provide a foundation for optimal application of this antimicrobial agent for improved control of sewer corrosion and odor management.IMPORTANCEHydrogen sulfide produced by SRB in sewers causes odor problems and results in serious deterioration of sewer assets that requires very costly and demanding rehabilitation. Currently, there is successful application of the antimicrobial agent free nitrous acid (FNA), the protonated form of nitrite, for the control of sulfide levels in sewers (G. Jiang et al., Water Res 47:4331–4339, 2013,http://dx.doi.org/10.1016/j.watres.2013.05.024). However, the details of the antimicrobial mechanisms of FNA are largely unknown. In this study, we identified the key responses (decreased anaerobic respiration, reducing FNA, combating oxidative stress, and shutting down protein synthesis) ofDesulfovibrio vulgarisHildenborough, a model sewer corrosion bacterium, to FNA exposure by examining the growth, physiological, and gene expression changes. These findings provide new insight and underpinning knowledge for understanding the responses ofD. vulgaristo FNA exposure, thereby benefiting the practical application of FNA for improved control of sewer corrosion and odor.
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Oh, Ri-On, and Chan-Gi Park. "Fracture and long-term aging characteristics of GFRP clamping plates for improved movable weirs." Polymers and Polymer Composites 27, no. 3 (December 28, 2018): 143–54. http://dx.doi.org/10.1177/0967391118820476.
Повний текст джерелаАнотація:
In this study, the durability of movable weirs was improved by replacing steel clamping plates with glass fiber-reinforced polymer (GFRP) material. Because the clamping plates of movable weirs are always in contact with water, the service life of weirs is reduced due to corrosion. Other environmental conditions also degrade movable weirs, such as exposure to continuous inundation, dry environments, repeated dry and wet conditions, and chemical environments. This study evaluated the absorption, fracture, and long-term aging properties of GFRP clamping plates for improved movable weirs. Absorption increased with immersion time in 60°C tap water, sodium sulfate (Na2SO4) solution, or calcium chloride (CaCl2) solution. However, the total absorption for 50 days and 100 days exposure was low, less than 0.50% and 0.62%, respectively. In fracture load tests, the GFRP clamping plates showed the largest reduction in strength after exposure to the CaCl2 solution; 70% and 67% of the control load were retained for exposures of 50 days and 100 days, respectively. After exposure to both tap water and the Na2SO4 solution, the GFRP clamping plates showed residual strengths of 77% and 69% after 50 days and 100 days exposure, respectively. The GFRP clamping plates showed 74% and 71% residual strength after exposure to repeated freeze–thaw environments for 50 days and 100 days, respectively, and 80% residual strength after exposure to all other environments for 50 days or 100 days. Both vertical and horizontal cracks were generated before fracture after exposure to an environment involving direct contact with moisture. Without moisture, only horizontal cracks were generated before fracture.
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Zhu, Yuanqing, Weihao Zhou, Chong Xia, and Qichen Hou. "Application and Development of Selective Catalytic Reduction Technology for Marine Low-Speed Diesel Engine: Trade-Off among High Sulfur Fuel, High Thermal Efficiency, and Low Pollution Emission." Atmosphere 13, no. 5 (May 2, 2022): 731. http://dx.doi.org/10.3390/atmos13050731.
Повний текст джерелаАнотація:
In recent years, the International Maritime Organization (IMO), Europe, and the United States and other countries have set up different emission control areas (ECA) for ship exhaust pollutants to enforce more stringent pollutant emission regulations. In order to meet the current IMO Tier III emission regulations, an after-treatment device must be installed in the exhaust system of the ship power plant to reduce the ship NOx emissions. At present, selective catalytic reduction technology (SCR) is one of the main technical routes to resolve excess NOx emissions of marine diesel engines, and is the only NOx emission reduction technology recognized by the IMO that can be used for various ship engines. Compared with the conventional low-pressure SCR system, the high-pressure SCR system can be applied to low-speed marine diesel engines that burn inferior fuels, but its working conditions are relatively harsh, and it can be susceptible to operational problems such as sulfuric acid corrosion, salt blockage, and switching delay during the actual ship tests and ship applications. Therefore, it is necessary to improve the design method and matching strategy of the high-pressure SCR system to achieve a more efficient and reliable operation. This article summarizes the technical characteristics and application problems of marine diesel engine SCR systems in detail, tracks the development trend of the catalytic reaction mechanism, engine tuning, and control strategy under high sulfur exhaust gas conditions. Results showed that low temperature is an important reason for the formation of ammonium nitrate, ammonium sulfate, and other deposits. Additionally, the formed deposits will directly affect the working performance of the SCR systems. The development of SCR technology for marine low-speed engines should be the compromise solution under the requirements of high sulfur fuel, high thermal efficiency, and low pollution emissions. Under the dual restrictions of high sulfur fuel and low exhaust temperature, the low-speed diesel engine SCR systems will inevitably sacrifice part of the engine economy to obtain higher denitrification efficiency and operational reliability.
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Schmitt, F., and C. F. Seyfried. "Sulfate Reduction in Sewer Sediments." Water Science and Technology 25, no. 8 (April 1, 1992): 83–90. http://dx.doi.org/10.2166/wst.1992.0182.
Повний текст джерелаАнотація:
The Institute of Sanitation Engineering and Waste Management of the University of Hannover made investigations on sediments in sanitary sewers. These were aimed to assess how sediments influence the sewer environment, with regard especially to water quality, gas atmosphere and corrosion progress. The sulfate reduction from sediments could be determined. It was 82 % higher than the reduction rate of biofilm. A prediction of sulfate reduction with equations from biofilm theory is possible. The biologically active sediment layer for sulfate reduction has a thickness of 5 to 7.5 cm. The sulfide formation in a large sanitary sewer in Hannover depends only on water temperature with a correlation of 91 %.
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Lytle, Darren A., Tammie L. Gerke, and D. J. Barry Maynard. "Effect of bacterial sulfate reduction on iron-corrosion scales." Journal - American Water Works Association 97, no. 10 (October 2005): 109–20. http://dx.doi.org/10.1002/j.1551-8833.2005.tb07500.x.
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Gu, Kun Peng, and Cheng Qi Wang. "Study on Corrosion Resistance Coefficient Assessment Method for Sulfate Resistance of Cementitious Material." Applied Mechanics and Materials 174-177 (May 2012): 624–30. http://dx.doi.org/10.4028/www.scientific.net/amm.174-177.624.
Повний текст джерелаАнотація:
By means of testing corrosion resistance coefficient of different cementitious material under the sulfate corrosion experimental conditions, sulfate resistance of cementitious material and assessment method are studied. The results show that 90d is proper corroded age for assessment sulfate resistance of cementitious material by corrosion resistance coefficient method, and the assessment method is put forwarded. Sulfate resistance of cementitious material can be divided into five classes according to corrosion resistance coefficient assessment method as follows: “very low”, “low”, “moderate”, “high” and “very high”. The sulfate resistance of Portland cement is better than ordinary Portland cement, and both of them are low. Mineral admixture with proper content can improve sulfate resistance of cementitious materia largely, but do not always available to all content. Sulfate corrosion mechanism of different kinds of cementitious material is analyzed.
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King, Fraser, Miroslav Kolář, Ignasi Puigdomenech, Petteri Pitkänen, and Christina Lilja. "Modeling microbial sulfate reduction and the consequences for corrosion of copper canisters." Materials and Corrosion 72, no. 1-2 (June 29, 2020): 339–47. http://dx.doi.org/10.1002/maco.202011770.
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Hương, Nguyễn Thị Thanh, Lê Bá Thắng, Lê Đức Bảo, and Đào Bich Thủy. "ATMOSPHERIC CORROSION RESISTANCE OF TRIVALENT AND HEXAVALENT CHROME CONVERSION COATING ON ZINC ELECTRODEPOSITS IN HANOI AFTER 5 YEARS NATURAL EXPOSURE." Vietnam Journal of Science and Technology 56, no. 3B (September 13, 2018): 27. http://dx.doi.org/10.15625/2525-2518/56/3b/12836.
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In this paper, the corrosion resistances obtained after five year exposure of zinc coatings, trivalent chrome conversion coatings (CCCs) and hexavalent CCCs on zinc electroplatings are compared and discussed. The compositions of corrosion products of sample surfaces after exposure are investigated. The results of analysis by means of X-ray diffraction show that the corrosion products formed on zinc coatings, trivalent CCCs, hexavalent CCCs in atmospheric conditions of Hanoi have the distinctions specialty of the humid tropical climates. Zinc sulfate hydroxide hydrate Zn4SO4(OH)6.H2O; Zinc carbonate hydroxide hydrate Zn4CO3(OH)6.H2O; Simonkolleite Zn5(OH)8Cl2.H2O; Chromium Sulfate Cr2(SO4)3; Zinc chloride sulfate hydroxide hydrat Zn12(OH)15(SO4)3Cl3.H2O; Eskolaite Cr2O3 have been identified. The presence of SO2 results in the formation of Zinc sulfate hydroxide hydrate Zn4SO4(OH)6.H2O. After 5 years of exposure in atmospheric conditions, the hexavalent CCCs on zinc coatings have show the best corrosion resistance and the least corrosion products. The corrosion resistance of the samples decreases in the order: 747 > SP25 ~ TM 3108 > Zn.
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Zhang, Shi Hong, Fei Kuang, Jin Zhong Zhang, Xiong Zhou, Gui Hong Lan, and Chang Jun Zou. "Influences of Thermophilic Sulfate-Reducing Bacteria on the Corrosion of Carbon Steel at Different Temperature." Advanced Materials Research 396-398 (November 2011): 1963–68. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.1963.
Повний текст джерелаАнотація:
The growth and the corrosion behaviors of thermophilic sulfate reducing bacteria (SRB), desulfotomaulum thermocisternum strain ST90, were studied in this work. It was found that the growth curves and the main reduction products were influenced greatly by the growth temperatures. The time of the exponential phase and the stable phase decreased with the increase of growth temperatures. The reduction product of this kind of SRB was mainly H2S when it grew at 60°C. With the decrease of growth temperatures, thiosulfate came up as an internal reduction product. The thiosulfate was re-reduced by SRB at the growth temperatures of 40 and 50°C. When the growth temperature came to 30°C, no H2S was generated. The regulation of corrosion rate changed was coincident with the changes of the main reduction products of the SRB. This kind of SRB could accelerate the corrosion rate of carbon steel when grew at higher temperature. But the corrosion rate of carbon steel could be inhibited when it grew at 30°C.
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Villanueva, Laura, Shelley A. Haveman, Zara M. Summers, and Derek R. Lovley. "Quantification of Desulfovibrio vulgaris Dissimilatory Sulfite Reductase Gene Expression during Electron Donor- and Electron Acceptor-Limited Growth." Applied and Environmental Microbiology 74, no. 18 (July 25, 2008): 5850–53. http://dx.doi.org/10.1128/aem.00399-08.
Повний текст джерелаАнотація:
ABSTRACT Previous studies have suggested that levels of transcripts for dsrA, a gene encoding a subunit of the dissimilatory sulfite reductase, are not directly related to the rates of sulfate reduction in sediments under all conditions. This phenomenon was further investigated with chemostat-grown Desulfovibrio vulgaris. Under sulfate-limiting conditions, dsrA transcript levels increased as the bulk rates of sulfate reduction in the chemostat increased, but transcript levels were similar at all sulfate reduction rates under electron donor-limiting conditions. When both electron donor- and electron acceptor-limiting conditions were considered, there was a direct correspondence between dsrA transcript levels and the rates of sulfate reduction per cell. These results suggest that dsrA transcript levels may provide important information on the metabolic state of sulfate reducers.
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Yamamoto-Ikemoto, Ryoko, Saburo Matsui, and Tomoaki Komori. "Ecological interactions among denitrification, poly-P accumulation, sulfate reduction, and filamentous sulfur bacteria in activated sludge." Water Science and Technology 30, no. 11 (December 1, 1994): 201–10. http://dx.doi.org/10.2166/wst.1994.0560.
Повний текст джерелаАнотація:
Effects of anoxic-oxic conditions on the growth of sulfate reduction, poly-P accumulation and filamentous sulfur bacteria were examined in the laboratory scale sequential batch reactors. In the anoxic-oxic conditions, denitrification bacteria are dominant. The growth of sulfate reducing bacteria and poly-P accumulating bacteria was suppressed. The number of sulfate reducing bacteria in the activated sludge was below 104 MPN/g MLSS, and the sulfate reduction rate was very low. Filamentous bulking was also suppressed. On the other hand, when nitrate was removed from the artificial wastewater, sulfate reducing bacteria could grow predominantly in the anaerobic conditions. The number of sulfate reducing bacteria was about 106∼107 MPN/g MLSS and the sulfate reduction rate increased (0.17 ∼ 0.21 g SO4/g MLSS·hr). Filamentous bacteria Type 021N increased over 103 cm/mg MLSS. Sodium molybdate was added to the artificial wastewater in order to prevent sulfate reduction. When the concentration of sodium molybdate increased to 980 mg/L, the number of sulfate reducing bacteria decreased to 103 ∼ 104 MPN/g MLSS and the sulfate reduction rate decreased. Filamentous bulking was completely suppressed in these conditions. These results show that sulfate reduction is a main trigger of the filamentous bulking due to Type 021N that can utilize reduced sulfur for an energy source.
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Boldyrev, K. A., A. V. Safonov, E. S. Abramova, N. A. Gladkikh, and D. V. Kryuchkov. "Research on the St3 Carbon Steel Corrosion in the Presence of Microorganisms Isolated from the Groundwater at the Yeniseyskiy Site." Radioactive Waste 16, no. 3 (2021): 103–13. http://dx.doi.org/10.25283/2587-9707-2021-3-103-113.
Повний текст джерелаАнотація:
The paper presents the experimental study exploring the corrosion of carbon steel St3 samples in the presence of a microbiological community sampled at the Yeniseiskiy site and the microbiota of bentonite clays. Depending on the conditions, an average 3—30-fold increase in the corrosion rate of steel was observed due to the biogenic and biogenic-mediated processes. The maximum steel degradation effect was observed at a temperature of 50°C in the presence of sulfate ions under conditions being considered optimal for sulfate-reducing bacteria. The developed steel corrosion model was used to determine the activation energy of the aerobic and anaerobic corrosion process.
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Somlev, Vladislav, and Sava Tishkov. "Anaerobic corrosion and bacterial sulfate reduction: Application for the purification of industrial wastewater." Geomicrobiology Journal 12, no. 1 (January 1994): 53–60. http://dx.doi.org/10.1080/01490459409377970.
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Gupta, Munish, Ashutosh Gupta, Makram T. Suidan, and Gregory D. Sayles. "Biotransformation rates of chloroform under anaerobic conditions—II. Sulfate reduction." Water Research 30, no. 6 (June 1996): 1387–94. http://dx.doi.org/10.1016/0043-1354(96)00006-1.
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Garcia, Roger, Fang Li, and Lester Hendrickson. "Microbiologically induced corrosion of stainless steel by Desulfovibrio vulgaris: An scanning electron microscope study." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 28–29. http://dx.doi.org/10.1017/s0424820100084442.
Повний текст джерелаАнотація:
The corrosion of mild steel by sulfate reducing bacteria has been studied quite extensively. However, with the replacement of mild steels with stainless steel in many of these applications numerous sightings of corroding stainless steel have been made as well. Initially, the cathodic depolarization theory was widely accepted as the mechanism for both. The essential part of this theory involves the removal of hydrogen from the metal surface. Hydrogenase in Desulfovibrio allows utilization of elemental hydrogen from the cathode of the corrosion cell. This causes the reduction of sulfate whereby the biological cell gets its energy via a respiration process. Finally, the oxygen from the sulfate becomes available to the cathode and hence corrosion is enhanced. Without this reducing action the cathode would become polarized thereby decreasing the EMF and lowering the corrosion rate. Among other proposed mechanisms are differential aeration cells and corrosive products produced by the bacteria.
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Zhao, Gaowen, Mei Shi, Mengzhen Guo, and Henghui Fan. "Degradation Mechanism of Concrete Subjected to External Sulfate Attack: Comparison of Different Curing Conditions." Materials 13, no. 14 (July 16, 2020): 3179. http://dx.doi.org/10.3390/ma13143179.
Повний текст джерелаАнотація:
Sulfate induced degradation of concrete brings great damage to concrete structures in saline or offshore areas. The degradation mechanism of cast-in-situ concrete still remains unclear. This paper investigates the degradation process and corresponding mechanism of cast-in-situ concrete when immersed in sulfate-rich corrosive environments. Concrete samples with different curing conditions were prepared and immersed in sulfate solutions for 12 months to simulate the corrosion of precast and cast-in-situ concrete structures, respectively. Tests regarding the changes of physical, chemical, and mechanical properties of concrete samples were conducted and recorded continuously during the immersion. Micro-structural and mineral methods were performed to analyze the changes of concrete samples after immersion. Results indicate that the corrosion process of cast-in-situ concrete is much faster than the degradation of precast concrete. Chemical attack is the main cause of degradation for both precast and cast-in-situ concrete. Concrete in the environment with higher sulfate concentration suffers more severe degradation. The water/cement ratio has a significant influence on the durability of concrete. A lower water/cement ratio results in obviously better resistance against sulfate attack for both precast and cast-in-situ concrete.
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Ng, Ding-Quan, and Yi-Pin Lin. "Effects of pH value, chloride and sulfate concentrations on galvanic corrosion between lead and copper in drinking water." Environmental Chemistry 13, no. 4 (2016): 602. http://dx.doi.org/10.1071/en15156.
Повний текст джерелаАнотація:
Environmental context Galvanic corrosion has been recently reported as the main cause of lead contamination in drinking water in urban cities. Conditions that can deter or promote galvanic corrosion, however, are not well understood. Fundamental investigations exploring the mechanisms and processes involved in galvanic corrosion in drinking water could help to implement proper corrective measures to safeguard public health from lead contamination. Abstract This study investigates the effects of pH value, chloride and sulfate concentrations on galvanic corrosion between lead and copper in drinking water. We hypothesised that galvanic corrosion would occur immediately when a lead–copper couple is first formed and that the release of lead would be suppressed by the subsequent formation of lead corrosion products. Therefore, unlike previous long-term studies using harvested lead pipes, batch experiments employing high-purity lead and copper (99.9%) wires under stagnant and completely mixed conditions were conducted for a 7-day period to test our hypotheses. It was found that enhanced lead release was indeed observed after the lead–copper couple was formed and the lead profiles after 48h were strongly influenced by lead corrosion products formed in the system. Under stagnant conditions, reducing pH and increasing either chloride or sulfate concentrations promoted lead release, leading to the formation of lead corrosion products such as cerussite and hydrocerussite as experiments proceeded. The effect of chloride concentration on total lead concentration measured in the aqueous phase was similar to that of sulfate at the same molar concentration, showing that the chloride-to-sulfate mass ratio may not provide a good indication for total lead concentration in water. This study provides essential information on fundamental mechanisms and processes involved in galvanic corrosion in drinking water and may be used to explain related phenomena observed in real drinking-water distribution systems.
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Xu, Chao, Hao-Hao Liao, You-Liang Chen, Xi Du, Bin Peng, and Tomas Manuel Fernandez-Steeger. "Corrosion Performance of Nano-TiO2-Modified Concrete under a Dry–Wet Sulfate Environment." Materials 14, no. 19 (October 8, 2021): 5900. http://dx.doi.org/10.3390/ma14195900.
Повний текст джерелаАнотація:
This study compared the effects of the sulfate dry–wet cycle on the properties of ordinary concrete and nano-TiO2-modified concrete, including the mass loss rate, ultrasonic wave velocity, compressive strength, and XRD characteristics. In addition, a series of compression simulations carried out using the PFC2D software are also presented for comparison. The results show the following: (1) with an increase in dry–wet cycles, the damage to the concrete gradually increased, and adding nano-TiO2 into ordinary concrete can improve the material’s sulfate resistance; (2) after 50 sulfate dry–wet cycles, the mass loss rate of ordinary concrete was –3.744%, while that of nano-TiO2-modified concrete was −1.363%; (3) the compressive strength of ordinary concrete was reduced from 41.53 to 25.12 MPa (a reduction of 39.51%), but the compressive strength of nano-TiO2-modified concrete was reduced from 49.91 to 32.12 MPa (a reduction of 35.64%); (4) after a sulfate dry–wet cycle, the nano-TiO2-modified concrete surface produced white crystalline products, considered to be ettringite based on the XRD analysis; (5) when considering the peak stress and strain of the concrete samples, the numerical results agreed well with the test results, indicating the reliability of the method.
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Pettersson, R. F. A., F. Karlsson, and J. Flyg. "Hot corrosion of two nickel-base superalloys under alkali sulfate deposition conditions." Materials at High Temperatures 26, no. 3 (September 2009): 251–57. http://dx.doi.org/10.3184/096034009x462232.
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Gu, Kun Peng, and Cheng Qi Wang. "Study on Expansion Rate Assessment Method for Sulfate Resistance of Cementitious Material." Advanced Materials Research 671-674 (March 2013): 1700–1705. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.1700.
Повний текст джерелаАнотація:
By means of testing expansion rate of different cementitious material under the sulfate corrosion experimental conditions, sulfate resistance of cementitious material and assessment method are studied. The results show that expansion rate of cementitious material increased with corroded age, and the assessment method is put forwarded. Sulfate resistance of cementitious material can be divided into five classes according to expansion rate assessment method as follows: "very low", "low", "moderate", "high" and "very high". The sulfate resistance of Portland cement is better than ordinary Portland cement, and both of them are very low. Mineral admixture with proper content can improve sulfate resistance of cementitious materia largely. Sulfate corrosion mechanism of different kinds of cementitious material is analyzed.
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Mountfort, Douglas O., Heinrich F. Kaspar, Rodney A. Asher, and Donna Sutherland. "Influences of Pond Geochemistry, Temperature, and Freeze-Thaw on Terminal Anaerobic Processes Occurring in Sediments of Six Ponds of the McMurdo Ice Shelf, near Bratina Island, Antarctica." Applied and Environmental Microbiology 69, no. 1 (January 2003): 583–92. http://dx.doi.org/10.1128/aem.69.1.583-592.2003.
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ABSTRACT The effects of freeze-thaw, freezing and sediment geochemistry on terminal anaerobic processes occurring in sediments taken from below cyanobacterial mats in meltwater ponds of the McMurdo Ice Shelf in Antarctica were investigated. Depending on the geochemical and physical status of the sediments (i.e., frozen or thawed), as well as passage of sediment through a freeze-thaw cycle, terminal carbon and electron flow shifted in which the proportions of hydrogen and acetate utilized for methanogenesis and sulfate reduction changed. Thus, in low-sulfate (or chloride) sediment which was thawed and incubated at 4°C, total carbon and electron flow were mediated by acetate-driven sulfate reduction and H2-driven methanogenesis. When the same sediments were incubated frozen, both methanogenesis and sulfate reduction decreased. However, under these conditions methanogenesis was favored over sulfate reduction, and carbon flow from acetate to methane increased relative to sulfate reduction; >70% of methane was contributed by acetate, and more than 80% of acetate was oxidized by pathways not coupled to sulfate reduction. In high-sulfate pond sediments, sulfate reduction was a major process mediating terminal carbon and electron flow in both unfrozen and frozen incubations. However, as with low-sulfate sediments, acetate oxidation became uncoupled from sulfate reduction with freezing. Geochemical and temperature effects could be expressed by linear models in which the log (methanogenesis to sulfate reduction) was negative log linear with respect to either temperature or the log of the sulfate (or chloride) concentration. From these relationships it was possible to predict the ratio for a given temperature (low-sulfate sediments) or sulfate (chloride) concentration. Small transitory changes, such as elevated sulfate reduction coupled to increased acetate turnover, resulted from application of a freeze-thaw cycle to low-salinity pond sediments. The results demonstrate how ecophysiological processes may change in anaerobic systems under extreme conditions (e.g., freezing) and provide new insights into microbial events occurring under these conditions.
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Du, Jian Min, Rui Min Jiao, Ying Shu Yuan, and Xiao Meng Zhu. "Research on the Anti-Sulfate and Chlorine Corrosion Property of Concrete." Advanced Materials Research 243-249 (May 2011): 5727–32. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.5727.
Повний текст джерелаАнотація:
In this paper wetting-drying cycle in the natural situation and increasing the concentration of sulfate solution is used in the laboratory , in order to accelerate the sulfate corrosion of concrete. The ultrasonic speed of sound on the opposite face is tested by ultrasonic technique regularly in order to reflect the change of concretes strength with the relative dynamic modulus.And at the same time the cube compressive strength test is used to detemine the corrosioned concretes intensity.Though the trend of relative dynamic modulus development which are in four different conditions to explain that the presence of chlorine ions affected the sulfate corrosion on concretes.Although in the compound solution, the corrosion degree should be depended on the concentration of sulfate ions and chloride ions in compound solution.
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Yoo, E. S., J. Libra, and U. Wiesmann. "Reduction of azo dyes by desulfovibrio desulfuricans." Water Science and Technology 41, no. 12 (June 1, 2000): 15–22. http://dx.doi.org/10.2166/wst.2000.0231.
Повний текст джерелаАнотація:
Azo dyes are widely used in textile finishing, and have become of concern in wastewater treatment because of their color, bio-recalcitrance, and potential toxicity to animals and humans. Thus, wastewater with azo dyes must be decolorized and furthermore mineralized in appropriate systems combining biological and chemical processes. In this study, the potential for sulfate reducing bacteria (SRB) to decolorize azo dyes was studied, employing the pure culture of Desulfovibrio desulfuricans (D. desulfuricans) with varying sulfate levels. Under sulfate-rich conditions, the sulfide produced from sulfate respiration with pyruvate (electron donor) by D. desulfuricans chemically decolorized the azo dyes C. I. Reactive Orange 96 (RO 96) and C. I. Reactive Red 120 (RR 120). Under sulfate-depleted conditions (≤0.1 mmol/L), the decolorization of RO 96 and RR 120 occurred in correlation with the fermentation of pyruvate by D. desulfuricans. It is suggested that the electrons liberated from the pyruvate oxidation were transferred via enzymes and/or coenzymes (electron carriers) to the dyes as alternative terminal electron acceptors, giving rise to decolorization, instead of to the protons (H+), resulting in the production of H2. Both decolorization pathways were compared in light of bioenergetics and engineering aspects.
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Kushkevych, Ivan, Jiří Cejnar, Jakub Treml, Dani Dordević, Peter Kollar, and Monika Vítězová. "Recent Advances in Metabolic Pathways of Sulfate Reduction in Intestinal Bacteria." Cells 9, no. 3 (March 12, 2020): 698. http://dx.doi.org/10.3390/cells9030698.
Повний текст джерелаАнотація:
Sulfate is present in foods, beverages, and drinking water. Its reduction and concentration in the gut depend on the intestinal microbiome activity, especially sulfate-reducing bacteria (SRB), which can be involved in inflammatory bowel disease (IBD). Assimilatory sulfate reduction (ASR) is present in all living organisms. In this process, sulfate is reduced to hydrogen sulfide and then included in cysteine and methionine biosynthesis. In contrast to assimilatory sulfate reduction, the dissimilatory process is typical for SRB. A terminal product of this metabolism pathway is hydrogen sulfide, which can be involved in gut inflammation and also causes problems in industries (due to corrosion effects). The aim of the review was to compare assimilatory and dissimilatory sulfate reduction (DSR). These processes occur in some species of intestinal bacteria (e.g., Escherichia and Desulfovibrio genera). The main attention was focused on the description of genes and their location in selected strains. Their coding expression of the enzymes is associated with anabolic processes in various intestinal bacteria. These analyzed recent advances can be important factors for proposing possibilities of metabolic pathway extension from hydrogen sulfide to cysteine in intestinal SRB. The switch from the DSR metabolic pathway to the ASR metabolic pathway is important since toxic sulfide is not produced as a final product.
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Guo, Jin-Jun, Peng-Qiang Liu, Cun-Liang Wu, and Kun Wang. "Effect of Dry–Wet Cycle Periods on Properties of Concrete under Sulfate Attack." Applied Sciences 11, no. 2 (January 19, 2021): 888. http://dx.doi.org/10.3390/app11020888.
Повний текст джерелаАнотація:
Dry–wet cycle conditions have significant effects on the corrosion of concrete under sulfate attack. However, previous studies have only applied them as a method for accelerating sulfate attack and not systematically studied them as an object. In order to explore the impact of sulfate attack with different dry–wet cycle periods on concrete, in this study, four dry–wet cycle periods (3, 7, 14, and 21 days) were selected. The flexure strength, relative dynamic modulus, and mass were tested, and the microstructures of the eroded specimens were also analyzed. The intensity and depth of sulfate erosion were influenced by the wet–dry cycle period. The results show that the deterioration of concrete first increased and then decreased with an extension of the dry–wet cycle period. Microstructural analysis indicated that, with an increase in the dry–wet cycle period, the corrosion depth of sulfate attack increased. Moreover, the erosion products such as ettringite and gypsum were greatly increased, in agreement with the macroscopic variations. However, excessively prolonging the dry–wet periods does not significantly further the deterioration of concrete’s performance. Therefore, considering the strength and depth of corrosion caused by sulfate attack, it would be appropriate to employ dry–wet cycle periods of 7–14 days under natural dry conditions in studies on concrete.
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Sigalevich, Pavel, Eran Meshorer, Yael Helman, and Yehuda Cohen. "Transition from Anaerobic to Aerobic Growth Conditions for the Sulfate-Reducing Bacterium Desulfovibrio oxyclinae Results in Flocculation." Applied and Environmental Microbiology 66, no. 11 (November 1, 2000): 5005–12. http://dx.doi.org/10.1128/aem.66.11.5005-5012.2000.
Повний текст джерелаАнотація:
ABSTRACT A chemostat culture of the sulfate-reducing bacteriumDesulfovibrio oxyclinae isolated from the oxic layer of a hypersaline cyanobacterial mat was grown anaerobically and then subjected to gassing with 1% oxygen, both at a dilution rate of 0.05 h−1. The sulfate reduction rate under anaerobic conditions was 370 nmol of SO4 2− mg of protein−1 min−1. At the onset of aerobic gassing, sulfate reduction decreased by 40%, although viable cell numbers did not decrease. After 42 h, the sulfate reduction rate returned to the level observed in the anaerobic culture. At this stage the growth yield increased by 180% compared to the anaerobic culture to 4.4 g of protein per mol of sulfate reduced. Protein content per cell increased at the same time by 40%. The oxygen consumption rate per milligram of protein measured in washed cell suspensions increased by 80%, and the thiosulfate reduction rate of the same samples increased by 29% with lactate as the electron donor. These findings indicated possible oxygen-dependent enhancement of growth. After 140 h of growth under oxygen flux, formation of cell aggregates 0.1 to 3 mm in diameter was observed. Micrometer-sized aggregates were found to form earlier, during the first hours of exposure to oxygen. The respiration rate of D. oxyclinaewas sufficient to create anoxia inside clumps larger than 3 μm, while the levels of dissolved oxygen in the growth vessel were 0.7 ± 0.5 μM. Aggregation of sulfate-reducing bacteria was observed within a Microcoleus chthonoplastes-dominated layer of a cyanobacterial mat under daily exposure to oxygen concentrations of up to 900 μM. Desulfonema-like sulfate-reducing bacteria were also common in this environment along with other nonaggregated sulfate-reducing bacteria. Two-dimensional mapping of sulfate reduction showed heterogeneity of sulfate reduction activity in this oxic zone.
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Sun, Jie, Ting Liang, Zhuang Zhou Ji, Rui Yan, and Jin Hong Meng. "Corrosion Resistance of Ternary Ni-Cu-P Coatings Prepared by Electroless Method on Carbon Steel." Advanced Materials Research 160-162 (November 2010): 479–83. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.479.
Повний текст джерелаАнотація:
Ni-Cu-P coatings were prepared by electroless deposition method on carbon steel. The pH value and concentrations of cupric sulfate were studied to character the deposition rate, corrosion resistance of Ni-Cu-P coatings in 3.5% NaCl solution. From the results, it was shown that the deposition rate of Ni-Cu-P coatings increased with the increasing of pH value. The deposition rate speeds up until the deposition rate keeps stable when the pH value is about 8.0-9.0. When pH value was 7.5, the coatings showed good corrosion resistance. In the same conditions of solution compositions and technological conditions, the concentration of cupric sulfate must be lower than 2g/L if the copper and nickel altogether co-deposited. The minimal corrosion current and excellent surface state for the coatings can be obtained when the concentration of cupric sulfate was about 0.8 g/L.
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Yamamoto-Ikemoto, Ryoko, Saburo Matsui, Tomoaki Komori, and E. J. Bosque-Hamilton. "Symbiosis and competition among sulfate reduction, filamentous sulfur, denitrification, and poly-p accumulation bacteria in the anaerobic-oxic activated sludge of a municipal plant." Water Science and Technology 34, no. 5-6 (September 1, 1996): 119–28. http://dx.doi.org/10.2166/wst.1996.0543.
Повний текст джерелаАнотація:
Symbiosis and competition were examined among sulfate reducing bacteria (SRB), filamentous sulfur bacteria (FSB), denitrification bacteria (DNB) and poly-P accumulation bacteria (PAB) in the activated sludge of a municipal plant operated under anaerobic-oxic conditions. Batch experiments were carried out using settled sewage from the same plant as the substrate under several conditions. Under oxic conditions, both sulfate reduction and sulfide oxidation occurred simultaneously, making a symbiotic relationship of SRB and FSB for establishment of a sulfur cycle sustaining the energy requirements. Under anoxic conditions, denitrification was dominant because DNB outcompeted PAB and SRB for organic acids. Under anaerobic conditions, phosphate release and sulfate reduction occurred simultaneously. SRB produced for moles of acetate from four moles of propionate and/or unknown substances by reduction of three moles of sulfate. PAB competed with sulfate-reducing bacteria for organic acids such as propionate. However, PAB utilized acetate produced by SRB.
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Chen, Zhong Bing, Uwe Kappelmeyer, and Peter Kuschk. "Benzene Removal in Laboratory Scale Model Wetland under Different Electron Acceptor Conditions Treating Sulfate-Rich Wastewater." Advanced Materials Research 955-959 (June 2014): 2083–86. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.2083.
Повний текст джерелаАнотація:
Constructed wetlands (CWs) are shown to be suitable for the treatment of water contaminated with benzene. However, due to the high sulfate concentration (around 850 mg/L) in influent, sulfate reduction will be stimulated in CWs. Subsequently, the toxicity of sulfide will be a catastrophe to the plants, and the treatment performance of CWs will be impaired. In this study, nitrite and nitrate were used as competitor with sulfate for electron acceptor to prevent the sulfate reduction. With the inflow benzene concentration ranged from 21.6-103 μg, and the accumulation of sulfide reached up to 39%, the removal efficiency of benzene decreased from 86% to 27%. However, with the addition of nitrite and nitrate, the sulfide accumulation was inhibited successfully, and the benzene removal efficiency recovered to 85%. In conclusion, both nitrite and nitrate can be an option for preventing sulfate reduction and sulfide toxicity in CWs treating sulfate-rich wastewater.
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Detmers, Jan, Volker Brüchert, Kirsten S. Habicht, and Jan Kuever. "Diversity of Sulfur Isotope Fractionations by Sulfate-Reducing Prokaryotes." Applied and Environmental Microbiology 67, no. 2 (February 1, 2001): 888–94. http://dx.doi.org/10.1128/aem.67.2.888-894.2001.
Повний текст джерелаАнотація:
ABSTRACT Batch culture experiments were performed with 32 different sulfate-reducing prokaryotes to explore the diversity in sulfur isotope fractionation during dissimilatory sulfate reduction by pure cultures. The selected strains reflect the phylogenetic and physiologic diversity of presently known sulfate reducers and cover a broad range of natural marine and freshwater habitats. Experimental conditions were designed to achieve optimum growth conditions with respect to electron donors, salinity, temperature, and pH. Under these optimized conditions, experimental fractionation factors ranged from 2.0 to 42.0‰. Salinity, incubation temperature, pH, and phylogeny had no systematic effect on the sulfur isotope fractionation. There was no correlation between isotope fractionation and sulfate reduction rate. The type of dissimilatory bisulfite reductase also had no effect on fractionation. Sulfate reducers that oxidized the carbon source completely to CO2 showed greater fractionations than sulfate reducers that released acetate as the final product of carbon oxidation. Different metabolic pathways and variable regulation of sulfate transport across the cell membrane all potentially affect isotope fractionation. Previous models that explained fractionation only in terms of sulfate reduction rates appear to be oversimplified. The species-specific physiology of each sulfate reducer thus needs to be taken into account to understand the regulation of sulfur isotope fractionation during dissimilatory sulfate reduction.
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Javed, M. A., W. C. Neil, G. McAdam, J. W. Moreau, and S. A. Wade. "Microbiologically Influenced Corrosion of Stainless Steel by Sulfate Reducing Bacteria: A Tale of Caution." Corrosion 76, no. 7 (April 2, 2020): 639–53. http://dx.doi.org/10.5006/3467.
Повний текст джерелаАнотація:
The influence of different experimental media composition and air purging on the potential for microbiologically influenced corrosion (MIC) of Type 304 stainless steel with sulfate-reducing bacteria (SRB) was investigated. Modified Baar’s (MB) medium, MB medium without iron ions and supplemented with sodium chloride (MBN), and air purged MBN medium (MBO) were used. Pitting corrosion attack was found on the surface of the coupons for all of the conditions tested including the abiotic tests, and detailed statistical analysis showed no significant difference between the pitting results. General corrosion and maximum pit penetration rates also showed no difference between the coupons exposed to different test conditions. Interestingly, the pits found on the surface of the coupons in all of the tested conditions were comparable in size/shape and depth to that of the inclusions present on the surface of the stainless steel coupons. These findings suggest that (i) the test conditions studied do not lead to increased corrosion rates of stainless steel with SRBs and (ii) care needs to be taken to avoid the pitfall of misinterpreting the corrosion of inclusions present on the surface of stainless steels, which can occur as a result of cleaning of the coupons, as MIC pits.
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Kokawa, Hiroyuki, Masahiko Shimada, Zhan Jie Wang, Yutaka S. Sato, and M. Michiuchi. "Grain Boundary Engineering for Intergranular Corrosion Resistant Austenitic Stainless Steel." Key Engineering Materials 261-263 (April 2004): 1005–10. http://dx.doi.org/10.4028/www.scientific.net/kem.261-263.1005.
Повний текст джерелаАнотація:
Optimum parameters in the thermomechanical treatment during grain boundary engineering (GBE) were investigated for improvement of intergranular corrosion resistance of type 304 austenitic stainless steel. The grain boundary character distribution (GBCD) was examined by orientation imaging microscopy (OIM). The intergranular corrosion resistance was evaluated by electrochemical potentiokinetic reactivation (EPR) and ferric sulfate-sulfuric acid tests. The sensitivity to intergranular corrosion was reduced by the thermomechanical treatment and indicated a minimum at a small roll-reduction. The frequency of coincidence-site-lattice (CSL) boundaries indicated a maximum at the small pre-strain. The ferric sulfate-sulfuric acid test showed much smaller corrosion rate in the thermomechanical-treated specimen than in the base material for long time sensitization. The optimum thermomechanical treatment introduced a high frequency of CSL boundaries and the clear discontinuity of corrosive random boundary network in the material, and resulted in the high intergranular corrosion resistance arresting the propagation of intergranular corrosion from the surface.
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Reis, M. A. M., L. M. D. Gonçalves, and M. J. T. Carrondo. "Sulfate Reduction in Acidogenic Phase Anaerobic Digestion." Water Science and Technology 20, no. 11-12 (November 1, 1988): 345–51. http://dx.doi.org/10.2166/wst.1988.0305.
Повний текст джерелаАнотація:
The acidogenic phase of a two-stage anaerobic digestion process using distillery molasses slops effluent with high sulfate concentrations (4.2-5.1 g/l) was investigated. Removal of sulfate was studied at pH 5.8, 6.2, 6.6 and in two different reactors: continuous stirred tank reactor and an upflow fixed film fixed bed reactor. Batch experiments were carried out to obtain the maximum specific growth rates of sulfate reducing bacteria (SRB) at the above mentioned pH values. The biological sulfate removal increased with pH and so did the acetic acid production from the fermentative bacteria and SRB. For the same pH and hydraulic retention time the sulfate reduction was more efficient in the fixed film reactor than in the CSTR. The soluble sulfides from the sulfate reduction presented at the acidogenic reactor effluent were precipitated before the methanogenic phase to avoid biogas contamination and methanogenic bacteria inhibition; under such conditions, sulfide concentrations in the biogas thus produced were very low and high methane volumetric rates of production were achieved.
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Zhang, Yu, Lijian Sun, and Jiti Zhou. "Simultaneous Biological and Chemical Removal of Sulfate and Fe(II)EDTA-NO in Anaerobic Conditions and Regulation of Sulfate Reduction Products." Minerals 9, no. 6 (May 28, 2019): 330. http://dx.doi.org/10.3390/min9060330.
Повний текст джерелаАнотація:
In the simultaneous flue gas desulfurization and denitrification by biological combined with chelating absorption technology, SO2 and NO are converted into sulfate and Fe(II)EDTA-NO which need to be reduced in biological reactor. Increasing the removal loads of sulfate and Fe(II)EDTA-NO and converting sulfate to elemental sulfur will benefit the application of this process. A moving-bed biofilm reactor was adopted for sulfate and Fe(II)EDTA-NO biological reduction. The removal efficiencies of the sulfate and Fe(II)EDTA-NO were 96% and 92% with the influent loads of 2.88 kg SO42−·m−3·d−1 and 0.48 kg NO·m−3·d−1. The sulfide produced by sulfate reduction could be reduced by increasing the concentrations of Fe(II)EDTA-NO and Fe(III)EDTA. The main reduction products of sulfate and Fe(II)EDTA-NO were elemental sulfur and N2. It was found that the dominant strain of sulfate reducing bacteria in the system was Desulfomicrobium. Pseudomonas, Sulfurovum and Arcobacter were involved in the reduction of Fe(II)EDTA-NO.