Literatura académica sobre el tema "Autotrophic anaerobic processes"
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Artículos de revistas sobre el tema "Autotrophic anaerobic processes"
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Laskar, Awata, Kasai y Katayama. "Anaerobic Dechlorination by a Humin-Dependent Pentachlorophenol-Dechlorinating Consortium under Autotrophic Conditions Induced by Homoacetogenesis". International Journal of Environmental Research and Public Health 16, n.º 16 (11 de agosto de 2019): 2873. http://dx.doi.org/10.3390/ijerph16162873.
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Anoxic aquifers suffer from energy limitations due to the unavailability of organic substrates, as dictated by hydrogen (H2) for various electron-accepting processes. This deficiency often results in the accumulation of persistent organic pollutants, where bioremediation using organic compounds often leads to secondary contamination. This study involves the reductive dechlorination of pentachlorophenol (PCP) by dechlorinators that do not use H2 directly, but rather through a reduced state of humin—a solid-phase humic substance—as the extracellular electron donor, which requires an organic donor such as formate, lactate, etc. This shortcoming was addressed by the development of an anaerobic mixed culture that was capable of reductively dechlorinating PCP using humin under autotrophic conditions induced by homoacetogenesis. Here, H2 was used for carbon-dioxide fixation to acetate; the acetate produced was used for the reduction of humin; and consequently used for dechlorination through reduced humin. The 16SrRNA gene sequencing analysis showed Dehalobacter and Dehalobacterium as the possible dechlorinators, while Clostridium and Oxobacter were identified as the homoacetogens. Thus, this work contributes to the development of an anaerobic consortium that balanced H2 dependency, where efficiency of humin reduction extends the applicability of anaerobic microbial remediation in aquifers through autotrophy, syntrophy, and reductive dechlorination.
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Campbell, Barbara J. y S. Craig Cary. "Abundance of Reverse Tricarboxylic Acid Cycle Genes in Free-Living Microorganisms at Deep-Sea Hydrothermal Vents". Applied and Environmental Microbiology 70, n.º 10 (octubre de 2004): 6282–89. http://dx.doi.org/10.1128/aem.70.10.6282-6289.2004.
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ABSTRACT Since the discovery of hydrothermal vents more than 25 years ago, the Calvin-Bassham-Benson (Calvin) cycle has been considered the principal carbon fixation pathway in this microbe-based ecosystem. However, on the basis of recent molecular data of cultured free-living and noncultured episymbiotic members of the epsilon subdivision of Proteobacteria and earlier carbon isotope data of primary consumers, an alternative autotrophic pathway may predominate. Here, genetic and culture-based approaches demonstrated the abundance of reverse tricarboxylic acid cycle genes compared to the abundance of Calvin cycle genes in microbial communities from two geographically distinct deep-sea hydrothermal vents. PCR with degenerate primers for three key genes in the reverse tricarboxylic acid cycle and form I and form II of ribulose 1,5-bisphosphate carboxylase/oxygenase (Calvin cycle marker gene) were utilized to demonstrate the abundance of the reverse tricarboxylic acid cycle genes in diverse vent samples. These genes were also expressed in at least one chimney sample. Diversity, similarity matrix, and phylogenetic analyses of cloned samples and amplified gene products from autotrophic enrichment cultures suggest that the majority of autotrophs that utilize the reverse tricarboxylic acid cycle are members of the epsilon subdivision of Proteobacteria. These results parallel the results of previously published molecular surveys of 16S rRNA genes, demonstrating the dominance of members of the epsilon subdivision of Proteobacteria in free-living hydrothermal vent communities. Members of the epsilon subdivision of Proteobacteria are also ubiquitous in many other microaerophilic to anaerobic sulfidic environments, such as the deep subsurface. Therefore, the reverse tricarboxylic acid cycle may be a major autotrophic pathway in these environments and significantly contribute to global autotrophic processes.
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Zhang, Quan, Xijun Xu, Xu Zhou y Chuan Chen. "Recent Advances in Autotrophic Biological Nitrogen Removal for Low Carbon Wastewater: A Review". Water 14, n.º 7 (30 de marzo de 2022): 1101. http://dx.doi.org/10.3390/w14071101.
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Due to carbon source dependence, conventional biological nitrogen removal (BNR) processes based on heterotrophic denitrification are suffering from great bottlenecks. The autotrophic BNR process represented by sulfur-driven autotrophic denitrification (SDAD) and anaerobic ammonium oxidation (anammox) provides a viable alternative for addressing low carbon wastewater. Whether for low carbon municipal wastewater or industrial wastewater with high nitrogen, the SDAD and anammox process can be suitably positioned accordingly. Herein, the recent advances and challenges to autotrophic BNR process guided by SDAD and anammox are systematically reviewed. Specifically, the present applications and crucial operation factors were discussed in detail. Besides, the microscopic interpretation of the process was deepened in the viewpoint of functional microbial species and their physiological characteristics. Furthermore, the current limitations and some future research priorities over the applications were identified and discussed from multiple perspectives. The obtained knowledge would provide insights into the application and optimization of the autotrophic BNR process, which will contribute to the establishment of a new generation of efficient and energy-saving wastewater nitrogen removal systems.
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Van Loosdrecht, M. C. M. y M. S. M. Jetten. "Microbiological conversions in nitrogen removal". Water Science and Technology 38, n.º 1 (1 de julio de 1998): 1–7. http://dx.doi.org/10.2166/wst.1998.0002.
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Nitrogen conversion processes are essential for most wastewater treatment systems. Due to the many possible conversions, and the complexity of analysing the reactions under actual conditions, there is much room for confusion. This review provides an overview of the possible microbiological nitrogen conversions described in literature. The relevance of these conversions with respect to wastewater treatment processes is discussed. Rates described for aerobic denitrification or denitrification by autotrophic nitrifiers are so low that these conversions probably do not play a significant role under practical conditions. Heterotrophic nitrification may be of relevance only when the wastewater contains a high COD/N ratio (>10). Anaerobic ammonium oxidation can occur in fully autotrophic systems with very long sludge retention times or biofilm systems. This conversion offers great opportunities since it allows us to denitrify with ammonium as electron donor, i.e. no organic substrate is needed in the nitrogen removal process.
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Weymann, D., H. Geistlinger, R. Well, C. von der Heide y H. Flessa. "Kinetics of N<sub>2</sub>O production and reduction in a nitrate-contaminated aquifer inferred from laboratory incubation experiments". Biogeosciences Discussions 7, n.º 1 (20 de enero de 2010): 503–43. http://dx.doi.org/10.5194/bgd-7-503-2010.
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Abstract. Knowledge of the kinetics of N2O production and reduction in groundwater is essential for the assessment of potential indirect emissions of the greenhouse gas. In this study, we investigated this kinetics using a laboratory approach. The results were compared to field measurements in order to examine their transferability to the in situ conditions. The study site was the unconfined, predominantly sandy Fuhrberger Feld aquifer in Northern Germany. A special characteristic of the aquifer is the occurrence of the vertically separated process zones of heterotrophic denitrification in the surface groundwater and of autotrophic denitrification in the deeper groundwater, respectively. The kinetics of N2O production and reduction in both process zones was studied during long-term anaerobic laboratory incubations of aquifer slurries using the 15N tracer technique. We measured N2O, N2 and NO3− concentrations as well as parameters of the aquifer material that were related to the relevant electron donors, i.e. organic carbon and sulfur. The anaerobic incubations showed a low denitrification activity of heterotrophic denitrification with initial rates between 0.0002 and 0.0133 mg N kg−1 day−1. The process was carbon limited due to the poor availability of its electron donor. In the autotrophic denitrification zone, initial denitrification rates were considerably higher, ranging between 0.0303 and 0.1480 mg N kg−1 d−1 and NO3− as well as N2O were completely removed within 60 to 198 days. N2O accumulated during heterotrophic and autotrophic denitrification, but maximum concentrations were substantially higher during the autotrophic process. The results revealed a satisfactory transferability of the laboratory incubations to the field scale for autotrophic denitrification, whereas the heterotrophic process less reflected the field conditions due to considerably lower N2O accumulation during laboratory incubation. Finally, we applied a conventional model using first-order-kinetics to determine the reaction rates of the NO3−-to-N2O step and the N2O-to-N2 step, and evaluated the reaction rate constants for both steps. The model yielded fits to the experimental data that were of limited goodness, indicating that a more sophisticated approach is essential to describe the investigated reaction kinetics satisfactorily.
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Beolchini, F., A. Dell’Anno, L. Rocchetti, Francesco Vegliò y R. Danovaro. "Biohydrometallurgy as a Remediation Strategy for Marine Sediments Contaminated by Heavy Metals". Advanced Materials Research 71-73 (mayo de 2009): 669–72. http://dx.doi.org/10.4028/www.scientific.net/amr.71-73.669.
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This paper deals with biohydrometallurgy applied for the remediation of sediments contaminated by heavy metals. Both metal mobilization by bioleaching and metal stabilization by sulfate reducing bacteria stimulation have been investigated. In the first case, leaching experiments were performed with different microbial strains: i) autotrophic Fe/S-oxidizing bacteria, ii) heterotrophic Fe reducing bacteria, and iii) a mix of them. The highest extraction yields were 90% for Cu, Cd, Hg and Zn and were achieved with a consortium of the autotrophic and the heterotrophic strains. In the second case, anaerobic microcosm experiments were performed according to a full factorial experiment where the main factors were: i) acetate, ii) inoculum of alloctonous sulfate-reducing bacteria and iii) treatment time. Significant changes on metal partitioning were observed in all the investigated treatments: in particular, Cu, Pb and Zn concentrations in the mobile fraction were reduced and the ones in the oxidizable fraction significantly increased. Anaerobic processes where hypothesized to lead to the formation of metal sulfides, relatively stable and less bioavailable than mobile fractions. The obtained results open new perspectives for biohydrometallurgy applied in the context of remediation strategies for sediments contaminated by heavy metals.
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Marakushev, Sergey A. y Ol'ga V. Belonogova. "Ideas and perspectives: Development of nascent autotrophic carbon fixation systems in various redox conditions of the fluid degassing on early Earth". Biogeosciences 16, n.º 8 (29 de abril de 2019): 1817–28. http://dx.doi.org/10.5194/bg-16-1817-2019.
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Abstract. The origin and development of the primary autotrophic metabolism on early Earth were influenced by the two main regimes of degassing of the Earth – reducing (predominance CH4) and oxidative (CO2). Among the existing theories of the autotrophic origin of life in hydrothermal environments, CO2 is usually considered to be the carbon source for nascent autotrophic metabolism. However, the ancestral carbon used in metabolism may have been derived from CH4 if the outflow of magma fluid to the surface of the Earth consisted mainly of methane. In such an environment, the primary autotrophic metabolic systems had to be methanotrophic. Due to the absence of molecular oxygen in the Archean conditions, this metabolism would have been anaerobic; i.e., oxidation of methane must be realized by inorganic high-potential electron acceptors. In light of the primacy and prevalence of CH4-dependent metabolism in hydrothermal systems of the ancient Earth, we propose a model of carbon fixation where the methane is fixed or transformed in a sequence of reactions in an autocatalytic methane–fumarate cycle. Nitrogen oxides are thermodynamically the most favorable among possible oxidants of methane; however, even the activity of oxygen created by mineral buffers of iron in hydrothermal conditions is sufficient for methanotrophic acetogenesis. The hydrothermal system model is considered in the form of a phase diagram, which demonstrates the area of redox and P and T conditions favorable for the development of the primary methanotrophic metabolism.
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Weymann, D., H. Geistlinger, R. Well, C. von der Heide y H. Flessa. "Kinetics of N<sub>2</sub>O production and reduction in a nitrate-contaminated aquifer inferred from laboratory incubation experiments". Biogeosciences 7, n.º 6 (20 de junio de 2010): 1953–72. http://dx.doi.org/10.5194/bg-7-1953-2010.
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Abstract. Knowledge of the kinetics of N2O production and reduction in groundwater is essential for the assessment of potential indirect emissions of the greenhouse gas. In the present study, we investigated this kinetics using a laboratory approach. The results were compared to field measurements in order to examine their transferability to the in situ conditions. The study site was the unconfined, predominantly sandy Fuhrberger Feld aquifer in northern Germany. A special characteristic of the aquifer is the occurrence of the vertically separated process zones of heterotrophic denitrification in the near-surface groundwater and of autotrophic denitrification in depths beyond 2–3 m below the groundwater table, respectively. The kinetics of N2O production and reduction in both process zones was studied during long-term anaerobic laboratory incubations of aquifer slurries using the 15N tracer technique. We measured N2O, N2, NO3-, NO2-, and SO42- concentrations as well as parameters of the aquifer material that were related to the relevant electron donors, i.e. organic carbon and pyrite. The laboratory incubations showed a low denitrification activity of heterotrophic denitrification with initial rates between 0.2 and 13 μg N kg−1 d−1. The process was carbon limited due to the poor availability of its electron donor. In the autotrophic denitrification zone, initial denitrification rates were considerably higher, ranging between 30 and 148 μg N kg−1 d−1, and NO3- as well as N2O were completely removed within 60 to 198 days. N2O accumulated during heterotrophic and autotrophic denitrification, but maximum concentrations were substantially higher during the autotrophic process. The results revealed a satisfactory transferability of the laboratory incubations to the field scale for autotrophic denitrification, whereas the heterotrophic process less reflected the field conditions due to considerably lower N2O accumulation during laboratory incubation. Finally, we applied a conventional model using first-order-kinetics to determine the reaction rate constants k1 for N2O production and k2 for N2O reduction, respectively. The goodness of fit to the experimental data was partly limited, indicating that a more sophisticated approach is essential to describe the investigated reaction kinetics satisfactorily.
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Desmidt, E., A. Monballiu, H. De Clippeleir, W. Verstraete y B. D. Meesschaert. "Autotrophic nitrogen removal after ureolytic phosphate precipitation to remove both endogenous and exogenous nitrogen". Water Science and Technology 67, n.º 7 (1 de abril de 2013): 1425–33. http://dx.doi.org/10.2166/wst.2013.666.
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Anaerobic digestion yields effluents rich in ammonium and phosphate and poor in biodegradable organic carbon, thereby making them less suitable for conventional biological nitrogen and phosphorus removal. In addition, the demand for fertilizers is increasing, energy prices are rising and global phosphate reserves are declining. This requires both changes in wastewater treatment technologies and implementation of new processes. In this contribution a description is given of the combination of a ureolytic phosphate precipitation (UPP) and an autotrophic nitrogen removal (ANR) process on the anaerobic effluent of a potato processing company. The results obtained show that it is possible to recover phosphate as struvite and to remove the nitrogen with the ANR process. The ANR process was performed in either one or two reactors (partial nitritation + Anammox). The one-reactor configuration operated stably when the dissolved oxygen was kept between 0.1 and 0.35 mg L−1. The best results for the two-reactor system were obtained when part of the effluent of the UPP was fully nitrified in a nitritation reactor and mixed in a 3:5 volumetric ratio with untreated ammonium-containing effluent. A phosphate and nitrogen removal efficiency of respectively 83 ± 1% and of 86 ± 7% was observed during this experiment.
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Sivalingam, Vasan, Carlos Dinamarca, Eshetu Janka, Sergey Kukankov, Shuai Wang y Rune Bakke. "Effect of Intermittent Aeration in a Hybrid Vertical Anaerobic Biofilm Reactor (HyVAB) for Reject Water Treatment". Water 12, n.º 4 (17 de abril de 2020): 1151. http://dx.doi.org/10.3390/w12041151.
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Water from anaerobic sludge dewatering (reject water that is recycled to the inlet main process treatment) from the Knarrdalstrand municipal wastewater treatment plant in Porsgrunn, Norway, contains 2.4 g/L of total chemical oxygen demand (TCOD) and 550 mg/L NH4-N (annual average). The high concentration of ammonium causes disturbances in the mainstream physical and chemical processes, while only a small fraction of the organics is biodegradable. A pilot-scale hybrid vertical anaerobic biofilm (HyVAB) reactor combining anaerobic and aerobic treatment was tested for reject water treatment to reduce process disturbances. The pilot HyVAB was prepared for the study with continuous aeration of the aerobic part of the reactor for 200 days, while two intermittent aeration schemes were applied during the three-month test period. Ammonium removal efficiency increased from 8% during the continuous aeration period to 50% at the end of the test when a short (7 min) aeration cycle was applied. COD removal was close to 20%, which was mainly obtained in the anaerobic stage and not significantly influenced by the aerations schemes. Simultaneous partial nitrification and denitrification were established in the biofilm that alternated between aerobic and anoxic conditions. The observed high ammonium removal is explained by two alternative shortcut processes via nitrite. The lack of biodegradable organics in the aerated stage suggests that most of the nitrogen removal was via the anammox pathway (autotrophic denitrification). The HyVAB, combining an anaerobic sludge bed and an intermittently aerated biofilm, appears to be an efficient process to treat high ammonium containing reject water.
Tesis sobre el tema "Autotrophic anaerobic processes"
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polizzi, cecilia. "Towards an integrated removal of nitrogen and sulphur in biological treatments of tannery-like wastewaters". Doctoral thesis, 2021. https://hdl.handle.net/2158/1247301.
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La tesi sviluppa un lavoro su processi innovativi per la rimozione dell'azoto e dello zolfo da acque reflue industriali. In particolare, è stata studiata la stabilità e l'efficienza del processo di denitrificazione autotrofa parziale tramite ossidazione di solfuro. La possibilità di accumulare alte concentrazioni di nitrito apre le porte per una sinergia innovativa con il processo anammox, per acque ricche di composti ridotti dello zolfo e dell'azoto. Le acque reflue conciarie sono state selezionate come caso studio di interesse. La tesi presenta i risultati del lavoro sperimentale, basato sulla conduzione di due reattori a scala pilota nonchè di test in batch, corredato da uno studio termodinamico sul processo di denitrificazione parziale.
The thesis focuses on the integration of novel processes for the biological removal of Nitrogen and Sulphur, specifically the anammox process and the sulphide-based autotrophic denitrification. Tannery wastewaters, highly loaded in nitrogen and sulphur compounds, have been selected as targeted industrial stream. Lab-scale and pilot-scale reactors have been conducted in order to study the two innovative processes and challenge a stable nitrite accumulation through sulphide-driven partial denitrification. A thermodynamic-based study on partial denitrification is presented as an integration of the experimental work.
Capítulos de libros sobre el tema "Autotrophic anaerobic processes"
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Belmonte, Marisol, Carmen Fajardo, Javiera Belén Toledo-Alarcón, Daniel Valenzuela Heredia, Lorena Jorquera, Ramón Méndez, Estela Tapia-Venegas y Gonzalo Ruiz-Filippi. "Autotrophic Denitrification Processes". En Technologies for the Treatment and Recovery of Nutrients from Industrial Wastewater, 147–73. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1037-6.ch006.
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Effluents coming from anaerobic digesters are characterized by a COD/N ratio between 2 and 10, high ammonia NH4+ concentrations about 500 mg/L and a temperature range of 25-35 ºC. To remove nitrogen from these effluents biological processes as the autotrophic denitrification with sulfur compounds, hydrogen or methane can be applied. The main goal of this chapter is to describe and evaluate the use of these processes from an economic point of view. The methanotrophic denitrification is the cheapest alternative to remove nitrate from effluents with low COD/N ratios.
Informes sobre el tema "Autotrophic anaerobic processes"
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Van Rijn, Jaap, Harold Schreier y Yossi Tal. Anaerobic ammonia oxidation as a novel approach for water treatment in marine and freshwater aquaculture recirculating systems. United States Department of Agriculture, diciembre de 2006. http://dx.doi.org/10.32747/2006.7696511.bard.
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Ammonia waste removal in recirculating aquaculture systems is typically accomplished via the action of nitrifying bacteria in specially designed biofilters that oxidize ammonia to produce nitrate. In the majority of these systems nitrate is discharged to the environment through frequent water exchanges. As environmental considerations have made it necessary to eliminate nitrate release, new strategies for nitrate consumption are being developed. In the funding period we showed that ammonia removal from wastewater could take place by an anaerobic ammonia oxidation process carried out by bacterial Planctomycetessp. Referred to as “anammox”, this process occurs in the absence of an organic source and in the presence of nitrite (or nitrate) as an electron acceptor as follows: NH₃ + HNO₂ -> N₂ + 2H₂O. Annamox has been estimated to result in savings of up to 90% of the costs associated with was wastewater treatment plants. Our objective was to study the applicability of the anammox process in a variety of recirculating aquaculture systems to determine optimal conditions necessary for efficient ammonia waste removal. Both seawater and freshwater systems operated with either conventional aerobic treatment of ammonia to nitrate (USA) or, in addition, denitrifying biofilters as well as anaerobic digestion of sludge (Israel) were tested. Molecular tools were used to screen and monitor different treatment compartments for the presence of Planctomycetes. Optimal conditions for the enrichment of the anammox bacteria were tested using laboratory scale biofilters as well as a semi-commercial system. Enrichment studies resulted in the isolation of some unique heterotrophic bacteria capable of plasmid-mediated autotrophic growth in the presence of ammonia and nitrite. Our studies have not only demonstrated the presence and viability of Planctomycetes spp. in recirculating marine and freshwater systems biofilter units but also demonstrated the applicability of the anammox process in these systems. Using our results we have developed treatment schemes that have allowed for optimizing the anammox process and applying it to recirculating systems.