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Control of Acid Mine Drainage Including Coal Pile and Ash Pond Seepage
Published in Donald A. Hammer, Constructed Wetlands for Wastewater Treatment, 2020
Possible mechanisms responsible for Fe retention in Sphagnum moss are exchange of Fe with other cations on negatively charged sites; specific binding of Fe to organic substrates; formation of Fe oxides (abiotically or from Fe-oxidizing bacteria); and formation of Fe sulfides (precipitation with H2S pro- duced by sulfate-reducing bacteria).9 In this pilot study, retention mechanisms for Fe in model wetlands were probably limited to abiotic interactions between the Sphagnum substrate and Fe. Microbial activity in model wetlands was likely inhibited by elevated temperatures (often exceeding 38°C) in the greenhouse containing the model wetlands. Iron-oxidizing bacteria, for example, are particularly sensitive to temperature, with optimum activity near 20°C, and iron-oxidizing efficiency declines sharply with higher temperatures.11
Microbiologically Induced Corrosion Associated with the Wet Storage of Subsea Pipelines (Wet Parking)
Published in Torben Lund Skovhus, Dennis Enning, Jason S. Lee, Microbiologically Influenced Corrosion in the Upstream Oil and Gas Industry, 2017
Fe2+ oxidation driven by iron-oxidizing bacteria leads to the formation of Fe3+ precipitates close to the microbial cells in a process called biomineralization. Iron mineralization can occur in the presence or absence of oxygen, depending on the type of microorganisms involved. Iron oxidation in neutral pH anoxic habitats is carried out by iron-oxidizing nitrate-reducing bacteria (Miot et al. 2009). Due to their low solubility at neutral pH, the Fe (III) by-products of this reaction precipitate rapidly in the direct vicinity of the cells. Biomineralization on corroding steel has been associated with the formation of tubercles and rusticles in seawater environments (Little et al. 2014). Although this process is thought to accelerate corrosion, the presence of tubercles on carbon steel has not always correlated with the onset of localized corrosion (Ray et al. 2011).
Exam Questions and Solutions
Published in Volodymyr Ivanov, Environmental Microbiology for Engineers, 2020
The following microbial groups may be applied for use in biological treatment: Ammonium can be removed by nitrifying and denitrifying bacteria.Chlorophenol can be removed by some anaerobic and aerobic bacteria.Iron (II) can be oxidized by iron-oxidizing bacteria.Naphthalene can be oxidized by some aerobic bacteria.
A Comprehensive Review on Cobalt Bioleaching from Primary and Tailings Sources
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Alex Kwasi Saim, Francis Kwaku Darteh
Indirect bioleaching (illustrated in Figure 2) does not involve direct contact between microorganisms and mineral particles and it is linked to generation of metabolic products. Generally, intentional bioleaching of sulfides (pyrite, arsenopyrite, marcasite and pyrrhotite) or pure chemical sources provide a source of ferric ions or sulfuric acid for leaching encapsulated or free metals from the ore. Despite the widespread knowledge of bio-assisted oxidation of sulfides, questions remain about the process’s mechanism and the precise function of the bacteria involved. Processes show that acid dissolution is brought about by the direct creation of protons (H+ ions) as a result of pyrite oxidation reactions involving bacteria or ferric ions (Reaction 1). As illustrated in Reaction (2), ferric ion is biologically obtained from ferrous ion owing to the activity of iron-oxidizing bacteria, which catalyzes the oxidation of Fe2+ to Fe3+ (Mishra et al. 2022). Pyrite is further dissolved by the ferric iron generated during oxidation. The iron in pyrite bioleaching is thought to undergo both oxidation and reduction inside the same closed cycle (Fe3+/Fe2+ loop).
Harnessing biodegradation potential of rapid sand filtration for organic micropollutant removal from drinking water: A review
Published in Critical Reviews in Environmental Science and Technology, 2021
Jinsong Wang, David de Ridder, Albert van der Wal, Nora B. Sutton
A key function of RSFs treating groundwater is the removal of Fe(II) and Mn(II), generally by a combination of chemical and biological oxidation (van Beek et al., 2012; Vries et al., 2017). The first treatment step of groundwater is usually aeration, where Fe(II) is oxidized into FeOx. Also, in this step, CO2 is removed, increasing the pH and the (chemical) oxidation rate of iron. The iron oxides are filtered out in the top layer of RSF. When aeration is limited, biological oxidation of Fe(II) can become more important. A number of iron oxidizing bacteria have been reported to participate in the biological oxidation of iron, such as: Leptothrix ochracea, Gallionella ferruginea, Toxothrix trichogenes, Thiobacillus ferrooxidans, and Crenothrix (Kirby et al., 1999; Michalakos et al., 1997; Rentz et al., 2007). Depending on groundwater composition, Mn(II) oxidation can also occur in RSF. As Mn(II) oxidation is a biological process, that has a slower oxidation rate than Fe(II) oxidation. Several manganese oxidizing bacteria (MnOB) have been identified on filter materials and in the water phase, including Pseudomonas sp., Streptomyces sp., and Leptothrix sp. (Bruins et al., 2014; Hu et al., 2020). The Mn and Fe oxides (MnOx and FeOx) formed and retained in RSF are able to remove OMPs by adsorption (Forrez et al., 2011) or by catalyzing chemical oxidation (Jian et al., 2019; Manoli et al., 2017) (Figure 2).
Degradation of nuclear fuel debris analog by siderophore-releasing microorganisms
Published in Journal of Nuclear Science and Technology, 2023
Toshihiko Ohnuki, Masahiko Nakase, Jiang Liu, Yuma Dotsuta, Yukihiko Satou, Toru Kitagaki, Naofumi Kozai
It is well known that iron-oxidizing bacteria accelerate corrosion by the formation of Fe(III) rust by oxidation of Fe2+, resulting in an increase in the gradient of O2 concentration and the potential difference between Fe(III) rust and metal [42]. In the present study, although SBs were not iron oxidizing bacteria, brown precipitates formed on the surface of the Fe metal area. The RBS and ERDA analyses (Figure 11) showed the presence of Fe and H+, indicating the formation of Fe oxides.