Sulfate-reducing Bacteria Concentration Research Articles

Mechanistic investigations of corrosion and localized corrosion of X80 steel in seawater comprising sulfate-reducing bacteria under continuous carbon starvation

Sulfate-reducing bacteria (SRB) corrosion is one of the main reasons leading to the service failure of engineering materials in the marine environment. An understanding of SRB corrosion especially under continuous organic carbon starvation is required. In this work, SRB corrosion of X80 pipeline steel under continuous organic carbon starvation was studied using mass loss, electrochemical measurements, and surface analysis. The effects of initial SRB concentrations on steel corrosion were also studied and discussed. The results indicated that more than 99% population of SRB die after 21 d of testing in various conditions, but there are still amounts of SRB survivors. SRB survivors with continued organic carbon starvation have a better adaptive ability and accelerated steel corrosion. Both the uniform and localized corrosion rates are also proportional to the initial SRB concentration as well as SRB survivors. The localized corrosion rate and density of corrosion pits of specimen corresponding to an initial SRB count of 108 cells/mL reach bigger values of (0.693 ± 0.114) mm/y and (1.94 ± 0.39)×104 pits/cm2, respectively, which are induced by the combination of the sessile and planktonic SRB.

Heavy metal removal and acid mine drainage neutralization with bioremediation approach

Mining Industry can improve the national economic situation; however, it also can damage the environment, mainly because of its wastewater that contains heavy metal and acidic solid compounds. When exposed to free air, sulfide minerals can be naturally oxidized and create acid mine drainage (AMD), a highly acidic waste that can mobilize heavy metals towards the environment. This literature study will discuss practical and sustainable biological processing to remove AAT. Sulfate Reducing Bacteria (SRB) were isolated from AMD polluted soil and grown inside an AMD-containing batch reactor. The environmental conditions (temperature, AMD concentration, SRB concentration, and contact time) were controlled during this research. The implementation of pH sampling was conducted every day, and the heavy metal final result was measured with an Inductive Coupled Plasma Optical Spectrophotometry or ICP-OES. SRB produced Hbiogenic2S that reacts with heavy metal and creates metal sulfide sediment. The remediation process by SRB will create biogenic alkalinity as an SRB side product that plays a significant role in neutralizing acidic water. Remediation is also influenced by organic compounds such as animal waste, rice, hay, or coconut husks. In this research, SRB plays a significant role as biosorbent that utilizes organic compounds as electron sources. The iron removal efficiency in AMD reached 96% and occurred on a contact time of 144 hours. To reach similar efficiency removal on a pilot scale, we planned AMD bioremediation on a tube-shaped reactor with 7.3m3 with 3.5 m height and 0.88 of each reactor radiuses. This bioremediation study has provided an alternative solution for environmental management quality due to AAT pollution in water and groundwater around mining areas.

Determination of sulfide production by Reducing Bacteria isolated in the injection water of an Iraqi oil field

Several oilfields undergo to reservoir souring, typically during water injection for secondary recovery, resulted in increasing concentrations of produced hydrogen sulfide (H2S). The main reason for this is the mechanism of generating hydrogen sulfide are the sulfate reducing bacteria (SRB). These bacteria use sulfate (So4) in the injection water as an electron acceptor and use organic acids which exist in formation water as a source of energy and carbon to generate H2S. In addition to that, the issues of health and safety, the existence of H2S decreases the worth of the produced hydrocarbon. The present study includes isolation and enumeration of sulfate reducing bacteria (SRB) from the injection and produced water of Ahdeb oilfield in Iraq by using Most Probable Number (MPN) technique. The Laboratory experimental work for production of sulfide with mix cultures of these bacteria was performed also with sodium lactate as an energy source. The experiments were carried out to determine the concentration of sulfide versus consumption of lactate in vitro. The concentration of sulfide is determined by using spectrophotometer method, whereas; the concentration of sodium lactate is calculated by using high performance liquid chromatography (HPLC) system. The experimental results demonstrates that the most numbers of bacteria in injection water are higher than the number in produced water samples. Whilst, the production of sulfide by SRB presents that inversely correlated to the concentration of sodium lactate. The growth experiments shows that the SRB concentration is increased in areas where the energy source and sulfate have high concentrations. Also, there is a direct relationship between SRB concentration and sulfide production. Therefore, the water injection from these bacteria must be treated before the injection to the reservoir to provide all the condition of SRB growth.

ABOUT MICROBIOLOGICAL CORROSION AT OIL FIELDS IN WESTERN SIBERIA

Background Operation of the most oil fields late stage of development leads to an increase in the number of complications associated with the oilfield equipment corrosion. One of the reasons for the spread of corrosion is the presence of sulfate reducing bacteria in the production of wells. A laboratory studies have shown that the corrosion rate in reservoir water containing even a small concentration of sulfate reducing bacteria is 10-12 times higher than in formation water that does not contain sulfate reducing bacteria. Aims and Objectives o analysis of corrosion processes of oil field and downhole pumping equipment; o on the basis of field data from the Pokhovsky and Vatyegansky fields, operating by OOO Lukoil-Western Siberia, to prove the optimal method for preventing corrosion processes in oilfield equipment. Results On the basis of wells data of the Lukoil-Western Siberia LLC, it has been established that sulfate-reducing bacteria presents in about 40 % of the produced water samples. The best method of preventing salt formation and corrosion is the injection of multicomponent synergistic and multifunctional compositions into the bottomhole formation zone and the annular space of wells, which are selected on the basis of timely analysis of failures of downhole pumping equipment and laboratory tests.

Fluorometric detection of sulfate-reducing bacteria via the aggregation-induced emission of glutathione-gold(I) complexes.

It is reported that gold(I)-thiolate complexes can display aggregation-induced emission (AIE) similar to organic fluorogens. On addition of lead(II) to glutathione-gold(I) complexes, a supermolecular structure of type GSH-Au(I)-Pb(II) is formed through strong coordination between Pb(II) and GSH. Its fluorescence is quenched by sulfide due to the formation of PbS which destroys the GSH-Au(I)-Pb(II) complex. The finding was used to design a method for fluorometric detection of sulfate-reducing bacteria (SRB) which produce sulfide. The time needed to reduce fluorescence to 10% of its initial intensity linearly dependent on the logarithm of the SRB concentrations in the ranging from 10 to 1 × 10^7 cfu mL-1. The assay time is also reduced down to 4 days even if the SRB concentration is as low as 10 cfu mL-1. Graphical abstract Schematic presentation of aggregation-induced emission (AIE)-active GSH-Au(I) complexes based fluorescence detection of SRB. The GSH-Au(I) complexes turn into aggregation and display strong emissive property in the presence of Pb2+. Then the fluorescence of GSH-Au(I)-Pb(II) complexes can be quenched by S2- generated by SRB.

Underground Bacteria Generates H2S and Trips Control Panels

Summary Instrument equipment shelters (IESs) are important control buildings within operating plants, housing the critical instrumentation and control system (ICS) panels that are essential for plant operations. At one such IES building in one of the plants operated by Abu Dhabi Gas Industries Limited (GASCO), frequent tripping of ICS panels was encountered, without pre-alarm indication, leading to plant upsets and posing risk to the safe operations of the plant. Occasionally, the odor of hydrogen sulfide (H2S) was observed. This paper addresses the measures undertaken to identify the source of generation and diffusion of corrosive agents into the IES and remedial measures to eliminate this chronic problem. A detailed study was carried out that included soil- and water-sample collection and specialized laboratory testing, collection and testing of electronic cards, discussion with control-system vendors, and desktop evaluation of data. Analysis of electronic cards identified corrosion of electronic components within the panels as the primary reason for the tripping of panels. Corrosion of electronic components was concluded to be caused mainly by diffusion of H2S into the building, also as confirmed by control-system vendors. Ingress of corrosive agents through air inlets/doors was eliminated as a cause because of the absence of any signs of corrosion in heating, ventilation, and air-conditioning (HVAC) air intakes and because of maintenance of positive air pressure within the building. Extensive investigation and testing of soil indicated the presence of a high concentration of sulfate-reducing bacteria (SRB) in the vicinity of the building. A high groundwater table containing sulfates provided nutrition to the SRB. The bacteria reduced the sulfates present in the groundwater to H2S. The H2S, thus generated, diffused into the building through cable entry sleeves, reaching the area beneath the false flooring on which panels were mounted, and subsequently entering the panels. The presence of conducive temperature and humidity facilitated the reaction of H2S with electronic cards, thereby causing corrosion and tripping of panels. The key remedial measures that were recommended—namely, dewatering the surrounding area and lowering groundwater levels to starve the bacteria, thus rendering it dormant and preventing H2S generation, and sealing of cable entry sleeves to prevent any external gas ingress into the building—were implemented, resulting in resolution of the issue and maintaining the safety and integrity of plant operations. Tripping of ICS panels because of H2S generation by bacteria present in soil is a rare phenomenon, not commonly encountered in oil and gas plants. In areas where the groundwater table is high, the construction of buildings needs to be planned carefully. Geotechnical investigation shall include testing for the presence of organic content, sulfates, and SRB in soil and groundwater, in addition to conventional tests.

Anaerobic Microbial Activities of a Nigerian Deep Offshore Oil Production Facility that Uses High Sulfate Sea Water for Injection

Aim: To evaluate the Anaerobic microbiological activi ties and souring potential of a Nigerian deep water offshore oil production facility with special emphasis on functional group activities. Methodology : CSB - K medium was used for the anaerobic microbial activity assay such as the ability to reduce sulfate by sulfate reducing bacteria (SRB), oxidize sulfide and reduce nitrate by the sulfide oxidizing, nitrate reducing bacteria (soNRB) and reduce nitrate by the heterotrophic nitrate reducing bacteria (hNRB) while API - RP - 38 and ZPRA - 5 broth media were used to quantify the presence of SRBs and acid producing bacteria respectively. Results: Results on the activities of anaerobic microorganisms indicated that sa mple 3N1(treated produced water) had the highest concentration of SRBs and Acid producing bacteria (10 5 and 10 7

Sulfate-reducing bacteria detection based on the photocatalytic property of microbial synthesized ZnS nanoparticles

This work presented a novel method for specific detection of sulfate-reducing bacteria (SRB) based on the photocatalytic property of ZnS nanoparticles. ZnS semiconductor nanoparticles were synthesized by taking advantage of the characteristic bacterial metabolite, sulfide, and then ZnS nanomaterials were used as photocatalyst for methylene blue (MB) photodegradation. As the amount of ZnS photocatalyst synthesized from microbe metabolized sulfide was affected by initial bacterial concentration before cultivation, the photodegradation ratio of MB was highly related with initial SRB concentration. Under the optimized conditions, a linear relationship between the MB photodegradation ratio and the logarithm of SRB concentration was observed in the range of 1.0×103–1.0×108cfumL−1. Besides, this proposed method showed excellent specificity for SRB detection. To the best of our knowledge, this is the first example of using the photocatalytic property of microbial synthesized ZnS for bacterial detection.

Determination of sulfate-reducing bacteria with chemical conversion from ZnO nanorods arrays to ZnS arrays

This work presents a novel specific detection method for sulfate-reducing bacteria (SRB) based on sulfuration conversion from ZnO arrays to ZnS arrays. The sulfuration process was conducted in two steps. First, ZnO@ZnS intermediate nanocomposite arrays were formed by the sulfuration reaction between ZnO and sulfide, which is the characteristic enzymatic metabolism product of SRB. Next, unconverted ZnO cores were washed away in ammonia buffer solutions, leaving ZnS arrays on the surface of ITO substrates. The array conversion process can be used for SRB detection because the final state of ZnS arrays was highly related with the amount of accumulated sulfide, which was decided by the initial concentration of SRB. Electrochemical impedance spectroscopy has been used to optimize experimental conditions and detect SRB in aqueous solutions. This SRB detection method based on arrays conversion from ZnO to ZnS can avoid the use of biological recognition elements, which are expensive and easy to lose specific recognizing abilities. In addition, compared with the widely used MPN method which would take up to 15days to accomplish the detection process, the proposed method can shorten the detection time greatly.

Impedimetric biosensor based on cell-mediated bioimprinted films for bacterial detection

This work presents the synthesis of bacteria-mediated bioimprinted films for selective bacterial detection. Marine pathogen sulfate-reducing bacteria (SRB) were chosen as the template bacteria. Chitosan (CS) doped with reduced graphene sheets (RGSs) was electrodeposited on an indium tin oxide electrode, and the resulting RGSs-CS hybrid film served as a platform for bacterial attachment. The electrodeposition conditions were optimized to obtain RGSs-CS hybrid films with excellent electrochemical performance. A layer of nonconductive CS film was deposited to embed the pathogen, and acetone was used to wash away the bacterial templates. Electrochemical impedance spectroscopy was performed to characterize the stepwise modification process and monitor the SRB population. Faradic impedance measurements revealed that the charge transfer resistance (Rct) increased with increased SRB concentration. A linear relationship between ΔRct and the logarithm of SRB concentration was obtained within the concentration range of 1.0×104cfumL−1 to 1.0×108cfumL−1. The impedimetric sensor showed good selectivity towards SRB based on size and shape. Hence, selectivity for bacterial detection can be improved if the bioimprinting technique is combined with other bio-recognition elements.

Direct immobilisation of antibodies on a bioinspired architecture as a sensing platform

A sensitive and selective immunosensor for the nonlabeled detection of sulfate-reducing bacteria (SRB) is constructed using a self-polymerised polydopamine film as the immobilisation platform. Self-polymerisation of dopamine is used as a powerful approach for applying multifunctional coatings onto the surface of a gold electrode. The polydopamine film is used not only as the immobilisation platform, but also as a cross-linker reagent for the immobilisation of the anti-SRB antibody. The polydopamine film is loaded with a high density of anti-SRB antibodies linked to the substrate to obtain high response signals. The formation and fabrication of the biosensor and the quantification of antibody anchoring are monitored, and SRB detection is performed by either quartz crystal microbalance (QCM) or electrochemical impedance spectroscopy (EIS). After modeling the impedance Nyquist plots of the SRB/anti-SRB/polydopamine/gold electrode for increasing concentrations of SRB, the electron transfer resistance ( R ct) is used as a measure of immunocomplex binding. The R ct is correlated with the concentration of bacterial cells in the range of 1.8 × 10 2 to 1.8 × 10 6 CFU mL −1; the detection limit is 50 CFU mL −1. This work demonstrates a new immobilisation platform for the development of a sensitive and label-less impedimetric and piezoelectric immunosensor. This immunosensor may be broadly applied in clinical diagnoses and the monitoring of water environmental pollution. The method proposed is distinct in its ease of application, use of a simple protocol, and mild reaction conditions. These allow it to be applied to a wide variety of materials.

A 3D-impedimetric immunosensor based on foam Ni for detection of sulfate-reducing bacteria

A 3D-immunosensor based on simple and efficient trapping platform (foam Ni) combining with adsorption of gold nanoparticles and specific recognition of biological/chemical molecular has been reported for detection of sulfate-reducing bacteria (SRB) using electrochemical impedance spectroscopy (EIS). The impedance spectra were also used to characterize the successful construct and stepwise modification of the impedimetric immunosensors. This results show that a linear relationship between electron-transfer resistance ( R ct) values and the logarithm of the SRB concentrations was obtained for the SRB concentration range of 2.1 × 10 1–2.1 × 10 7 cfu/ml. Additionally, the fabricated immunosensor shows a high selectivity against other bacteria.

Evaluation of the sulfate-reducing bacterial population associated with stored swine slurry

Hydrogen sulfide, produced by sulfate-reducing bacteria (SRB), is one of the most potent malodors emitted from anaerobic swine waste storage systems. However, little is known about the prevalence and diversity of SRB in those systems. The goals of this study were to evaluate the SRB population in swine manure storage systems and to develop quantitative, real-time PCR (QRT-PCR) assays to target four of the SRB groups. Dissimilatory sulfite reductase (DSR) gene sequences were obtained from swine slurry stored in underground pits (43 clones) or in lagoons (34 clones). QRT-PCR assays were designed to target the dsrA gene of four novel groups of SRB. Sequences of dsrA clones from slurry samples grouped with those from three different cultured SRB: Desulfobulbus sp. (46 clones), Desulfovibrio sp. (24 clones and 5 isolates), and Desulfobacterium sp. (7 clones). However, DsrA sequences from swine slurry clones were generally less than 85% similar to those of cultured organisms. SRB from all four targeted SRB groups were detected in underground waste storage pits (6.6×10 3–8.5×10 7 dsrA copies mL −1 slurry), while only two groups of SRB were detected in lagoons (3.2×10 5–2.5×10 6 dsrA copies mL −1 slurry). To date, this is the only study to evaluate the phylogeny and concentration of SRB in any livestock waste storage system. The new QRT-PCR assays should facilitate sensitive, specific detection of the four novel groups of SRB in livestock waste storage systems.

Numerical Evaluation of Biocide Treatment against Sulfate Reducing Bacteria in Oilfield Water Pipelines

A simple two-dimensional mathematical model capable of describing the interactions taking place in the bulk fluid and biofilm between sulfate reducing bacteria (SRB), substrates and biocide agents was used for the numerical evaluation of biocide treatment against SRB. The characteristics inherent to thick biofilms formed in large diameter oilfield pipelines were taken into account by assuming that the biocide treatment will remove little of the biofilm and not kill the SRB present in the biofilm. The evaluation model considered SRB disinfection/proliferation, and biocide deactivation within the bulk fluid, as well as many features of biofilm interactions with the bulk fluid such as mass transfer, live SRB detachment and biocide agent deactivation. These interactions are represented by simple coefficients as far as possible. Simulation results, using reported kinetic parameters for SRB, acetate and biocide agents such as chlorine and glutaraldehyde, showed that biocide treatments in oilfield water pipelines are sensitive to the disinfection rate coefficient and the biocide agent concentration as well as to the decay rate coefficient of the biocide agent in the bulk fluid, but are not sensitive to the biocide deactivation rate on the biofilm surface, nor to the SRB concentration in the biofilm. Various extreme conditions of biocide treatments were simulated using the proposed discretization method, which was adapted to take into account the biofilm interactions with the bulk fluid, to investigate the sensitivity of the numerical method and the suitability of the model developed to determine minimum effective biocide concentrations.

Characterization of Sulfate Reducing Bacteria Isolated from Cooling Towers

In this study, the occurrence and metabolic capacities of sulfate reducing bacteria (SRB) were studied in 36 water samples taken from cooling towers of 30 different buildings, such as hotels and business centres in Istanbul. SRB were present in 14 cooling towers out of 30 (46.6%) buildings and while the lowest concentration of SRB was 10 cells/mL, the highest concentration was determined as 10(4) cells/mL. After the distribution of SRB within cooling towers was determined, several strains of SRB were isolated and characterized metabolically. The isolated strains were composed of vibroid cells, growing anaerobically by using sulfate as electron acceptor and lactate or pyruvate as electron donor. They could be related to the genus Desulfovibrio. In addition, the recorded temperature of water samples was between 12 and 33 degrees C and a significant relationship between the number of SRB and the water temperatures was not found.

Hydrogen sources for signal attenuation in optical fibers

Laboratory studies established that corroding galvanized steel and hydrogen-producing bacteria can generate enough hydrogen to cause appreciable signal attenuation in optical fibers. Simulations of these two effects in the laboratory caused hydrogen indicators to increase up to 7.2 dB/km. The effect of hydrogen-producing bacteria can be suppressed by sulfate-reducing bacteria (SRB) in the absence or limited presence of fermentable hydrocarbons. In the abundant presence ofthese hydrocarbons, the optical fibers will attenuate, and even high concentrations of SRB cannot counteract this effect. During the fermentation process, acetic and butyric acids are produced. If these acids lower the pH of the environment below 5, the hydrogen is consumed by the formation of <i>n</i>-butanol and acetone. Data from fiber attenuation experiments in H₂/N₂ gas mixtures show that the attenuation at saturation increases approximately linearly with increasing <i>p</i>(H₂) and decreases with increasing temperature.

Effects of Maturation on the Characteristics of Wastewater Stabilization Pond Sludges

The physical-chemical characteristics, (pH, Eh, S2−, TOC, NH4+, particulate Kjeldahl nitrogen (PKN), total phosphorus (TP) and PO43−.) of the sludge accumulated in the first of a series of wastewater stabilization ponds nave been studied in two vertical profiles in order to characterize the effects of the maturation of the sludge. The effects on the concentration of faecal indicator organisms and salmonella have also been determined. The maturation leads to an increased density of the sludge and to the removal of about 80% of the TOC, 70% of PN and of 75% of TP initially present in the fresh sludge. The concentrations of sulfate reducing bacteria do not change and those of the total coliforms, the faecal coliforms and the faecal streptococci are only moderately modified, as the maximum decrease is 4 log. Salmonellae only are found in the superficial sediment layer, which might indicate their rapid inactivation.