Academic literature on the topic 'Dissolved oxygen Dam removal'
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Journal articles on the topic "Dissolved oxygen Dam removal":
1
Abbott, Katherine M., Peter A. Zaidel, Allison H. Roy, Kristopher M. Houle, and Keith H. Nislow. "Investigating impacts of small dams and dam removal on dissolved oxygen in streams." PLOS ONE 17, no. 11 (November 17, 2022): e0277647. http://dx.doi.org/10.1371/journal.pone.0277647.
Abstract:
Small surface-release dams are prevalent across North American watersheds and can alter stream flow, thermal regimes, nutrient dynamics, and sediment transport. These dams are often implicated as a cause of negative water quality impacts—including reduced dissolved oxygen (DO)—and dam removal is increasingly employed to restore natural stream processes and improve DO. Published impacts of small dams on DO vary widely across sites, and even less is known about the extent and timescale of DO recovery following removal. Therefore, we sought to quantify the effects of small dams and dam removal on DO and determine the dam, stream, and watershed characteristics driving inter-site variation in responses. We deployed continuous data loggers for 3 weeks during summer months in upstream (reference), impoundment, and downstream reaches at each of 15 dammed sites and collected equivalent data at 10 of those sites following dam removal. Prior to dam removal, most sites (60%) experienced a decrease in DO (an average of 1.15 mg/L lower) within the impoundment relative to upstream, but no consistent impacts on diel ranges or on downstream reaches. Before dam removal, 5 impacted stream reaches experienced minimum DO levels below acceptable water quality standards (<5 mg/L); after dam removal, 4 of 5 of these reaches met DO standards. Sites with wider impoundments relative to upstream widths and sites located in watersheds with more cultivated land experienced the greatest decreases in impoundment DO relative to upstream. Within one year following dam removal, impoundment DO recovered to upstream reference conditions at 80% of sites, with the magnitude of recovery strongly related to the magnitude of pre-removal impacts. These data suggest that broadly, small dams negatively affect stream DO, and the extent of effects are modulated by impoundment geometry and watershed characteristics. These results may help practitioners to prioritize restoration efforts at those sites where small dams are having outsized impacts, and therefore where the greatest water quality benefits may occur.
2
Zhang, Yiding, Li Zhang, and William J. Mitsch. "Predicting river aquatic productivity and dissolved oxygen before and after dam removal." Ecological Engineering 72 (November 2014): 125–37. http://dx.doi.org/10.1016/j.ecoleng.2014.04.026.
3
Tian, Zhuang, Can Wang, and Min Ji. "Full-scale dissolved air flotation (DAF) equipment for emergency treatment of eutrophic water." Water Science and Technology 77, no. 7 (February 23, 2018): 1802–9. http://dx.doi.org/10.2166/wst.2018.046.
Abstract:
Abstract Eutrophication of urban rivers has caused severe environmental problems due to the pollution from point and diffuse sources. Although eutrophication can be alleviated by reducing the input to the river system, fast-treating terminal control technologies, especially under emergent situations, should be developed to reduce risks induced by eutrophication. The present study developed an emergency purification device based on dissolved air flotation (DAF) technology. After equipment commissioning and parameter optimization for applications in the field of engineering, the device was found to effectively remove total phosphorus, chlorophyll a, chemical oxygen demand, and turbidity in water by controlling the coagulant dosage and adjusting the gas-liquid mixing pump parameters. Dissolved air in water could enhance dissolved oxygen, and dissolved oxygen in polluted rivers could be raised from 0.2–2 mg/L to 3–3.5 mg/L. Removal of total nitrogen was poor because the majority of nitrogen contents were dissolved. Finally, DAF has been proven to be a promising technology due to its ease of implementation, low equipment investment requirement, and low operation cost.
4
Chung, Wayne, and Stephanie Young. "Evaluation of a chemical dissolved air flotation system for the treatment of restaurant dishwasher effluent." Canadian Journal of Civil Engineering 40, no. 12 (December 2013): 1164–72. http://dx.doi.org/10.1139/cjce-2012-0357.
Abstract:
Restaurant dishwashers consume a large quantity of fresh water and produce significant amounts of high strength oily wastewater which may cause serious problems when discharged into the sewer. An analysis of restaurant dishwasher effluent (RDE) from a busy upscale restaurant identified high levels of oil and grease, chemical oxygen demand (COD), biochemical oxygen demand (BOD), alkalinity, pH, and chlorine, but low levels of nitrogen and phosphorus. In this study, RDE was treated using an internationally patented chemical dissolved air flotation (chemical DAF) system. The chemical DAF system was designed so that coagulation, flocculation, and flotation processes could be carried out within the same reactor. The treatment system is therefore small and compact and suitable for use in restaurants where space is limited. The treatment performance of the chemical DAF was evaluated by determining optimal process conditions, contaminant removal efficiencies, and residual contaminant concentrations. It was found that removal efficiencies of 98.90%, 93.16%, 98.68%, 90.04%, and 88.20% could be achieved under optimal process conditions for turbidity, oil, TSS, BOD5, and COD, respectively. Total coliform and E. coli were not detected in either the raw dishwasher effluent or the treated dishwasher effluent due to the use of sodium hypochlorite as a dishwashing sanitizer. Water quality of the treated effluent met the criteria put forth in the Canadian Guidelines for Domestic Reclaimed Water for Use in Toilet and Urinal Flushing, with the exception of BOD5. Present findings suggest that chemical DAF is a promising treatment process for the removal of contaminants from restaurant dishwasher effluent.
5
Tong, Kun, Yi He Zhang, Jia Cai Xie, and Qi Hui Song. "Treatment of Heavy Oil Wastewater with Two Stages DAF Combined with ASP and I-BF Process - A Field Pilot Test." Advanced Materials Research 518-523 (May 2012): 2950–55. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.2950.
Abstract:
A field pilot test was constructed on a two stage Dissolved Air Floatation (DAF) combined with Activated Sludge Process (ASP) and Immobilized microorganism biological filter (I-BF) has been constructed in Liaohe oilfield, China to treat heavy oil wastewater with large amounts of dissolved recalcitrant organic compounds and low nutrient of nitrogen and phosphorus. By operating the system for 185 days, chemical oxygen demand (COD) removal rates were 67.9 % and 88.4 % in DAF and I-BF effluents, respectively. Environment Scanning electron microscope (ESEM) showed that large quantity of filamentous microorganisms was immobilized on carriers without causing foaming or bulking. This integrated system appeared to be a useful option for the treatment of heavy oil wastewater in Liaohe oil field.
6
Choi, Miyoung, Dong Whan Choi, Jung Yeol Lee, Young Suk Kim, Bun Su Kim, and Byoung Ho Lee. "Removal of pharmaceutical residue in municipal wastewater by DAF (dissolved air flotation)–MBR (membrane bioreactor) and ozone oxidation." Water Science and Technology 66, no. 12 (December 1, 2012): 2546–55. http://dx.doi.org/10.2166/wst.2012.429.
Abstract:
Growing attention is given to pharmaceutical residue in the water environment. It is known that pharmaceuticals are able to survive from a series of wastewater treatment processes. Concerns regarding pharmaceutical residues are attributed to the fact that they are being detected in water and sediment environment ubiquitously. Pharmaceutical treatment using a series of wastewater treatment processes of the DAF (dissolved air flotation)–MBR (membrane bioreactor)–ozone oxidation was conducted in the study. DAF, without addition of coagulant, could remove CODcr (chemical oxygen demand by Cr) up to over 70%, BOD 73%, SS 83%, T-N 55%, NH4+ 23%, and T-P 65% in influent of municipal wastewater. Average removal rates of water quality parameters by the DAF–MBR system were very high, e.g. CODcr 95.88%, BOD5 99.66%, CODmn (chemical oxygen demand by Mn) 93.63%, T-N 69.75%, NH4-N 98.46%, T-P 78.23%, and SS 99.51%, which satisfy effluent water quality standards. Despite the high removal rate of the wastewater treatment system, pharmaceuticals were eliminated to be about 50–99% by the MBR system, depending on specific pharmaceuticals. Ibuprofen was well removed by MBR system up to over 95%, while removal rate of bezafibrate ranged between 50 and 90%. With over 5 mg/l of ozone oxidation, most pharmaceuticals which survived the DAF–MBR process were removed completely or resulted in very low survival rate within the range of few micrograms per litre. However, some pharmaceuticals such as bezafibrate and naproxen tended to be resistant to ozone oxidation.
7
Del Nery, V., M. H. Z. Damianovic, R. B. Moura, E. Pozzi, E. C. Pires, and E. Foresti. "Poultry slaughterhouse wastewater treatment plant for high quality effluent." Water Science and Technology 73, no. 2 (September 26, 2015): 309–16. http://dx.doi.org/10.2166/wst.2015.494.
Abstract:
This paper assesses a wastewater treatment plant (WWTP) regarding the technology used, as well as organic matter and nutrient removal efficiencies aiming to optimize the treatment processes involved and wastewater reclamation. The WWTP consists of a dissolved air flotation (DAF) system, an upflow anaerobic sludge blanket (UASB) reactor, an aerated-facultative pond (AFP) and a chemical-DAF system. The removal efficiencies of chemical oxygen demand (COD) (97.9 ± 1.0%), biochemical oxygen demand (BOD) (98.6 ± 1.0%) and oil and grease (O&G) (91.1 ± 5.2%) at the WWTP, the nitrogen concentration of 17 ± 11 mgN-NH3 and phosphorus concentration of 1.34 ± 0.93 mgPO4−3/L in the final effluent indicate that the processes used are suitable to comply with discharge standards in water bodies. Nitrification and denitrification tests conducted using biomass collected at three AFP points indicated that nitrification and denitrification could take place in the pond.
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Tetteh, Emmanuel Kweinor, and Sudesh Rathilal. "INVESTIGATING DISSOLVED AIR FLOTATION FACTORS FOR OIL REFINERY WASTEWATER TREATMENT." CBU International Conference Proceedings 6 (September 25, 2018): 1173–77. http://dx.doi.org/10.12955/cbup.v6.1311.
Abstract:
The global demand for petrochemical and petroleum industry products unavoidably generates large volumes of oil refinery wastewater (ORW). The complete treatment, reclamation and disposal of the ORW to an acceptable environmental limit is currently a challenge to most of the petroleum industries. With the current development in conventional treatment methods viz. coagulation, dissolved air flotation (DAF), and biological and membrane separation processes. DAF, which is well-established separation process, effectively employs microbubbles as a carrier phase for separation. Although, DAF is frequently used in combined water and wastewater treatment plants, its fundamental characteristics and operational parameters have not yet been fully investigated for the treatment of ORW. In this study, the correlation and effects of the parameters understudy (coagulant dosage, air saturator pressure, air-water ratio and rising rate) on chemical oxygen demand, soap oil and grease, turbidity and total suspended solids removal from ORW were examined experimentally using a laboratory DAF system. The results showed that increasing the saturator working pressure and the rising rate had less effect on the system, than increasing the air-water ratio. The agglomeration of the oil droplets was found to depend solely on the polyaluminum sulphate (PAS) dosage to destabilize the oil droplets. The DAF treatability performance showed over 80% removal of the contaminants at optimum conditions of pH of 5, PAS dosage of 10 mg/L, rising rate of 15 minutes, air saturator pressure of 300-500 kPa, and air-water ratio of 5-15%. The PAS dosage was found to be the most significant factor. Therefore, a moderate increase of the PAS dosage under these optimum conditions will increase the DAF efficiency in the treatment of ORW.
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Jamieson, Bryan Lee, Alex Augusto Gonçalves, and Graham A. Gagnon. "Evaluation of treatment options for Atlantic Canadian seafood processing plant effluentA paper submitted to the Journal of Environmental Engineering and Science." Canadian Journal of Civil Engineering 37, no. 1 (January 2010): 167–78. http://dx.doi.org/10.1139/l09-127.
Abstract:
The purpose of this study was to evaluate different effluent treatment options for Atlantic Canadian seafood processing plants. Bench-scale testing with a 25-mesh screen, sedimentation (SED), and dissolved air flotation (DAF) was conducted. Treatment by SED and DAF was successful in reducing contaminant concentrations with maximum observed percent reductions: biochemical oxygen demand, BOD5 (90%); chemical oxygen demand, COD (60%); turbidity (99%); total suspended solids, TSS (95%); and ammonia nitrogen, NH3-N (50%). Bench-scale 25-mesh screen runs for select effluent types showed poor reduction efficiencies and appeared to provide inadequate removal of contaminants. Sedimentation and DAF using alum were effective at removing solids but less effective at removing soluble effluent components. Improved performance may be possible with further treatment technology optimization on an effluent specific basis.
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Azhar, Muhammad Rizwan, Paul Nolan, Keith Cadee, and Mehdi Khiadani. "Chemical-Free Biologically Enhanced Primary Treatment of Raw Wastewater for Improved Capture Carbon." Water 14, no. 23 (November 24, 2022): 3825. http://dx.doi.org/10.3390/w14233825.
Abstract:
Conventional wastewater treatment processes require extensive energy inputs for their operations. Biologically enhanced primary treatment (BEPT) is a promising technology to capture incoming organics that may be utilized to produce biogas and potentially hydrogen with further downstream processing. This study involved a biologically enhanced primary treatment (BEPT) of raw wastewater at bench and pilot-scale using activated sludge (AS) addition and dissolved air flotation (DAF) using raw wastewater at a municipal wastewater facility in Western Australia with average chemical oxygen demand of ~800 mg/L. The results of pilot-scale testing showed an improved removal performance for total chemical oxygen demand (COD-T), soluble chemical oxygen demand (COD-S), and total suspended solids (TSS) compared to conventional primary treatment (PT). Specifically, average COD-T, COD-S and TSS removals for BEPT were 33.3%, 13.5% and 45%, respectively which was 10%, 100% and 6% higher than PT. Moreover, the sludge produced from BEPT had a high solids content of 4.8 g/L, which might not need further thickening prior to anaerobic digestion. It is important to note that no chemicals were used during BEPT testing, which makes the process very cost-effective.
Dissertations / Theses on the topic "Dissolved oxygen Dam removal":
1
Zhang, Yiding. "Predicting River Aquatic Productivity and Dissolved Oxygen before and after Dam Removal in Central Ohio, USA." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337983076.
2
Ba, Mouhamadoul Moustapha. "Dynamique des interactions physico-chimiques en zone hyporhéique : influence des crues et de la suppression des barrages." Electronic Thesis or Diss., Université de Rennes (2023-....), 2023. http://www.theses.fr/2023URENB076.
Abstract:
Dans le contexte de la rivière Sélune en France, où deux barrages sont en cours de retrait pour rétablir la continuité hydro-sédimentaire de la rivière, cette thèse s'est fixée pour objectif de comprendre les impacts potentiels de ces changements sur la dynamique de la zone hyporhéique. Cette zone, cruciale dans les cycles hydrologiques ainsi que pour la reproduction de certaines espèces de poisson, demeure mal comprise du fait du faible nombre de donnée disponibles. Pour pallier à ce problème, un réseau de capteurs autonomes mesurant différentes variables physico-chimiques a été déployé à partir d'octobre 2021, sur une durée de 2 ans. La méthodologie de cette étude repose sur l'analyse des gradients physico-chimiques verticaux dans les sédiments du lit de la rivière, en se penchant sur l'oxygène et la conductivité. L'hétérogénéité de la perméabilité a également été examinée grâce à des mesures de conductivité électrique. Les résultats ont révélé des variations spatiales significatives de la perméabilité du lit. En particulier, l'impact du flux sédimentaire lié à l'arasement des barrages a été observé, provoquant une diminution de la perméabilité dans certaines zones. En ce qui concerne l'oxygène dissous, les variations observées sont liées aux régimes d'infiltration et d'exfiltration, avec possiblement des baisses temporaires dues à l'activité microbienne en réponse à l'apport de matière organique. De plus, l'arrivée de sédiments en mai 2022 semble avoir entraîné une période prolongée d'anoxie, avec potentiellement des conséquences majeures pour la faune aquatique. Cette recherche a contribué à une meilleure compréhension de la zone hyporhéique et a souligné l'impact significatif du flux sédimentaire sur la perméabilité, la dynamique de l'oxygène et le phénomène de colmatage. Elle a également ouvert de nouvelles perspectives pour l'analyse des propriétés hydrothermiques du lit de la rivière, des flux d'eau et l'utilisation de mesures de conductivité électrique pour estimer la profondeur des échanges nappe-rivière, ainsi que le développement de modèles théoriques pour prédire le transport des éléments dissous et leur dégradationIn the context of the Selune River in France, where two dams are currently being removed to restore hydro-sedimentary continuity in the river, this thesis aimed at understanding the potential impacts of these changes on the dynamics of the hyporheic zone. This zone, crucial for the reproduction of certain species and economic activities, requires in-depth monitoring. To achieve this, a network of autonomous sensors measuring various physicochemical variables was deployed starting in October 2021, for a duration of 2 years. The methodology of this study is based on the analysis of vertical physicochemical gradients in the riverbed sediments, focusing on oxygen and conductivity. The heterogeneity of permeability was also examined through measurements of electrical conductivity. The results revealed significant spatial variations in bed permeability. Specifically, the impact of sediment transport released by the dam removal was observed, causing a decrease in permeability in certain areas. Regarding dissolved oxygen, local variations were related to infiltration and exfiltration regimes, with temporary decreases due to microbial activity in response to organic matter input. Furthermore, the arrival of sediments in May 2022 led to an extended period of anoxia, with potentially significant consequences for aquatic fauna. This research has contributed to a better understanding of the hyporheic zone and emphasized the significant impact of sediment transport on permeability, oxygen dynamics, and clogging phenomena. It has also opened new perspectives for the analysis of hydrothermal properties of the riverbed, water flow, and the use of electrical conductivity measurements to estimate the depth of groundwater-river exchanges, as well as the development of theoretical models to predict the transport and degradation of dissolved elements
3
Beck, Jason Lee. "Optimization of Biological Nitrogen Removal From Fermented Dairy Manure Using Low Levels of Dissolved Oxygen." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/35593.
Abstract:
A pilot scale nitrogen (N) removal system was constructed and operated for approximately 365 days and was designed to remove inorganic total ammonia nitrogen (TAN) from solids-separated dairy manure. An anaerobic fermenter, upstream of the N removal reactor, produced volatile fatty acids (VFAs), to be used as an electron donor to fuel denitrification, and TAN at a COD:N ratio of 18:1. However, sufficient amounts of non-VFA COD was produced by the fermenter to fuel the denitrification reaction at an average NO3- removal rate of 5.3 ± 2 mg/L NO3--N. Total ammonia N was removed from the fermenter effluent in an N removal reactor where a series of aerobic and anoxic zones facilitated aerobic TAN oxidation and anoxic NO3- and NO2- reduction. The minimum dissolved oxygen (DO) concentration allowing for complete TAN removal was found to be 0.8 mg/L. However, TAN removal rates were less than predicted using default nitrifying kinetic parameters in BioWin®, a biological modeling simulator, which indicated the presence of a nitrification inhibitor in fermented dairy manure. Furthermore, an N balance during the aerobic zone indicated that simultaneous nitrification-denitrification (SND) was occurring in the aerobic zone of the N removal reactor and was most apparent at DO concentrations below 1.3 mg/L.
A series of nitrite generation rate (NGR) experiments confirmed the presence of an inhibitor in fermented dairy manure. A model sensitivity analysis determined that the most sensitive ammonia oxidizing bacteria (AOB) kinetic parameters were the maximum specific growth rate, , and the substrate half saturation coefficient, . Nitrifying inhibition terms of competitive, non-competitive, mixed competitive, and un-competitive were applied to the growth rate equation in BioWin® but an accurate representation of the observed TAN removal rates in the pilot scale system could not be found by adjusting the kinetic parameters alone. Reducing the default BioWin® hydrolysis rate by approximately 50% produced a more accurate calibration for all inhibition terms tested indicating that the hydrolyization of organic N in dairy manure is less than typical municipal waste water.Master of Science
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楊龍元 and Lung-yuen Christopher Yeong. "Removal of wastewater cod and nitrogen using fibrous packing media." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31210636.
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Owusu-Agyeman, Isaac. "Systems for ammonium concentration for further removal in the partial nitritation/anammox technology." Thesis, KTH, VA-teknik, Vatten, Avlopp och Avfall, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99356.
Abstract:
Anammox is one of the main processes discovered quite recently for removal of ammonium from wastewater. Anammox process is cost effective, in that low energy and carbon source is needed. Partial nitritation is a perquisite for anammox in wastewater treatment for removal nitrogen and therefore partial nitritation/Anammox technology is studied substantially and applied in full-scale. However, the technology at present can only be used to treat high rich ammonium streams. Application of Anammox for treatment of low ammonium wastewater is not possible because of low yield of Anammox bacteria. The study aimed at devising strategies for using the Anammox technology to treat wastewater streams with low concentration of ammonium nitrogen. The objective was to get systems that could concentrate ammonium from low ammonium waste streams, so as to be able to treat it with partial nitritation/Anammox process. Two methods were used to concentrate ammonium: ion exchange and reverse osmosis. Ion exchange method was used to concentrate UASB effluents of about 24 - 40 mg NH4-N/l to 188 - 367 mg NH4-N/l respectively which is about 9 times the initial concentrations. At VRF 5, 163 mg NH4-N/l concentrate was attained from 41.8 mg NH4-N/l RO feed. Results also showed that concentrates from both methods are able to be treated with partial nitritation/Anammox technology. However it took more than 32 hours to complete treatment of ion exchange concentrates while it took less than 24 hours to finish the partial nitritation/Anammox process of RO concentrates. The longer time taken can be attributed to high salinity of the concentrates which is as a result of NaCl which was used for regeneration in ion exchange process. Both ion exchange and reverse osmosis are viable methods for concentrating ammonium from UASB effluents. Dissolved oxygen was very important factor that influenced the biological process.
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Nair, Arthur William. "Investigation of the Effects of Sequential Anaerobic, Anoxic and Aerobic Zones on Dissolved Oxygen Transfer Parameters in a biological Nutrient Removal Pilot Plant." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/46264.
Abstract:
Bench and pilot scale determinations of the volumetric oxygen transfer coefficient, KLa, were performed on an improved A²/O biological nutrient removal (BNR) pilot plant. Effluent from a full scale primary clarifier, used as pilot plant influent, was found to have an alpha (ratio of process to clean water KLa) of 0.71 as determined in a 21 liter bench scale reactor and an alpha of 0.332 as determined in a 0.45 m³ aeration basin of the 2.4 m³ pilot plant. Alpha of a 1:1 mixture of primary clarifier effluent with pilot plant return activated sludge was determined to be 0.94 at bench scale and 0.71 at pilot scale. An assay of alphas through the initial non aerated treatment zones of the pilot plant using the bench scale reactor indicated that alphas peaked in the effluent of the first anaerobic zone (alpha equal to 1.01) and were lower in the second anaerobic zone and first anoxic zone. An assay of alphas in the three pilot plant series sideline aeration basins indicated that alpha was maximum in the first aeration basin (alpha equal to 0.905) and were lower in the second and third aeration basins (0.716 and 0.661 respectively). A consistent increase in average surface tension was noted from the first to second to third aeration basins, however the differences were not statistically significant. A comparison of pilot plant alphas determined in the first aeration basin following anaerobic nominal hydraulic retention times of 0.0, 0.21, 0.43, and 0.64 hours yielded alpha values of 0.71, 0.94, 0.64, and 0.74 respectively. Like the assay using the bench scale reactor, the alpha values at pilot scale peaked following treatment in only one anaerobic zone (nominal HRT of 0.21 hours). The study concludes that short exposures in an initial anaerobic reactor as required for biological phosphorus removal may benefit oxygen transfer efficiency through increased alphas, however the benefits of long periods of anaerobic reaction time (over 0.43 hours) are uncertain.Master of Science
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Petre, Catalin Florin. "Alkaline oxidation of hydrosulfide and methyl mercaptide by iron/cerium oxide-hydroxide in presence of dissolved oxygen. Possible application for removal of Total Reduced Sulfur (TRS) emissions in the Pulp & Paper industry." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24330/24330.pdf.
Abstract:
Le sulfure d'hydrogène (H2S) et le méthyle-mercaptan (MM) sont les contaminants odorants les plus abondants parmi le quatuor qui compose les soufres réduits totaux (SRT) (H2S, CH3SH, (CH3)2S, (CH3)2S2) dans les émissions atmosphériques des industries papetières Kraft. L'association de SRT avec suffisamment d'oxygène peut être exploitée sur la base de la chimie du fer, pour convertir les SRT gazeux en produits non-volatils et non-odorants. Le procédé utilise l'oxyde-hydroxyde de Fe/Ce (Fe/CeOx) dans des solutions alcalines où l'absorption oxydative de H2S et de MM (sous forme d’ hydrosulfure et de méthyle mercapture) est favorisée. Des protocoles d'électrophorèse capillaire ont été développés pour la séparation, l'identification et la quantification de l’hydrosulfure, du méthyle mercapture, des polysulfures, du thiosulfate, du sulfate, du sulfite et du tétrathionate. La cinétique et le mécanisme de la réaction anoxique entre l’hydrosulfure et le Fe/CeOx ont été étudiés aux pH [8.0-11.0] dans un réacteur batch liquide-solide. La plupart du Fe(II) produit à pH = 9.5 reste associée à la surface de l'oxyde dans l’échelle de temps des expériences. L’hydrosulfure a été converti en thiosulfate, polysulfures et, probablement, en soufre élémentaire, alors que le Fe2+ lixivié et le thiosulfate ont montré une production équimolaire pour pH ≥ 9.5. Un mécanisme de réaction détaillé pour l'oxydation anoxique d’hydrosulfure par le Fe/CeOx a été proposé pour expliquer la formation des produits ci-dessus et dont un modèle cinétique a été dérivé pour décrire les vitesses de lixiviation du Fe(II) et de consommation d’hydrosulfure. En conditions oxiques à pH [8.5-11.0], le Fe/CeOx oxyde l’hydrosulfure via une voie combinée hétérogène-homogène pour former les mêmes produits qu’en anoxique. L'oxygène accélère l'oxydation de l’hydrosulfure par le Fe/CeOx par un facteur de plus de trois en comparaison avec la réaction anoxique. L'oxygène assume un double rôle : d'abord, il ré-oxyde le fer de Fe(II) à Fe(III); en second lieu, il favorise l'oxydation de l`hydrosulfure vers les polysulfures et de ces-ci vers le thiosulfate, un produit non-volatile et non-odorant. L'oxydation du méthyle mercapture par Fe/CeOx a été étudiée aux différentes valeurs du pH [10.5-12] en conditions anoxique et oxique. Des conversions de mercapture allant jusqu'à 100% ont été obtenues en conditions oxiques bien que la conversion du mercapture se soit avérée tributaire de la quantité d'oxygène dissous. L'interférence avec l’hydrosulfure co-mélangé avec le mercapture a causé une inhibition dans la conversion des deux polluants. Une telle inhibition est due aux polysulfures naissants formés par l'oxydation de l’hydrosulfure. L'oxydation du méthyle mercapture par le système Fe/CeOx/O2 n'a pas affecté la capacité de régénération du Fe(III) de surface par l'oxygène dissous. Fe/CeOx semble être un matériau très prometteur pour un éventuel procédé de lavage-oxydatif pour l’élimination du méthyle mercaptan dans les émissions des industries papetières de type Kraft.Hydrogen sulfide (H2S) and methyl mercaptan (MM) are the most abundant odor contaminants among the Total Reduced Sulfur (TRS) quartet (H2S, CH3SH, (CH3)2S, (CH3)2S2) contained in the Kraft mill atmospheric emissions. The association of TRS with sufficient oxygen could be taken advantage of, based on the iron chemistry, to convert TRS gases to odorless non-volatile products. The process uses Fe/Ce oxide-hydroxide (Fe/CeOx) slurried in alkaline solutions where both H2S and MM oxidative absorption (in the form of hydrosulfide and methyl mercaptide) is promoted. Capillary electrophoresis protocols were developed for the separation, identification and quantification of hydrosulfide, methyl mercaptide, polysulfides, thiosulfate, sulfate, sulfite and tetrathionate. The kinetics and mechanism of the anoxic reaction between hydrosulfide and Fe/CeOx were studied for pH [8.0-11.0] in a batch slurry reactor. Most of Fe(II) produced at pH = 9.5 remained associated with the oxide surface in the time-frame of the experiments. Hydrosulfide was converted into polysulfides, thiosulfate and, probably, elemental sulfur, while the leached Fe2+ and thiosulfate dovetailed equimolarly. A detailed reaction pathway of the anoxic oxidation of hydrosulfide by Fe/CeOx was proposed for explaining the formation of above products and whereof a kinetic model was derived to depict the Fe2+ leaching and hydrosulfide consumption rates. In oxic conditions at pH [8.5-11.0], Fe/CeOx will oxidize hydrosulfide via a combined heterogeneous-homogenous pathway to yield the same products as in anoxia. Oxygen enhanced Fe/CeOx-promoted hydrosulfide oxidation by more than a factor three when compared with anoxic reaction. Oxygen is believed to have a double role: first, it re-oxidizes iron from Fe(II) to Fe(III); second, it promotes oxidation of hydrosulfide to polysulfides which in turn transforms into non-volatile, non-odorous thiosulfate. The reaction between methyl mercaptide and Fe/CeOx was studied at different pH values [10.5-12] both in anoxic and oxic conditions. Up to 100% conversions of mercaptide were obtained in oxic conditions, though the mercaptide conversion was found to be tributary to the dissolved oxygen. Interference with hydrosulfide co-mixed with mercaptide caused an inhibition in the conversion for both pollutants, due to the incipient polysulfides formation. The oxidation of methyl mercaptide by the Fe/CeOx/O2 system did not affect the re-oxidative regeneration of surface Fe(III) by O2. Fe/CeOx appears to be a very promising material for a redox-scrubbing process targeting the TRS emissions from Kraft mills, via in situ regeneration of Fe(III) sites by O2.
Inscrit au Tableau d'honneur de la Faculté des études supérieures
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Petre, Cătălin Florin. "Alkaline oxidation of hydrosulfide and methyl mercaptide by iron/cerium oxide-hydroxide in presence of dissolved oxygen : possible application for removal of Total Reduced Sulfur (TRS) emissions in the Pulp & Paper industry." Doctoral thesis, Université Laval, 2007. http://hdl.handle.net/20.500.11794/19640.
Abstract:
Tableau d'honneur de la Faculté des études supérieures et postdoctorales, 2006-2007Le sulfure d'hydrogène (H2S) et le méthyle-mercaptan (MM) sont les contaminants odorants les plus abondants parmi le quatuor qui compose les soufres réduits totaux (SRT) (H2S, CH3SH, (CH3)2S, (CH3)2S2) dans les émissions atmosphériques des industries papetières Kraft. L'association de SRT avec suffisamment d'oxygène peut être exploitée sur la base de la chimie du fer, pour convertir les SRT gazeux en produits non-volatils et non-odorants. Le procédé utilise l'oxyde-hydroxyde de Fe/Ce (Fe/CeOx) dans des solutions alcalines où l'absorption oxydative de H2S et de MM (sous forme d’ hydrosulfure et de méthyle mercapture) est favorisée. Des protocoles d'électrophorèse capillaire ont été développés pour la séparation, l'identification et la quantification de l’hydrosulfure, du méthyle mercapture, des polysulfures, du thiosulfate, du sulfate, du sulfite et du tétrathionate. La cinétique et le mécanisme de la réaction anoxique entre l’hydrosulfure et le Fe/CeOx ont été étudiés aux pH [8.0-11.0] dans un réacteur batch liquide-solide. La plupart du Fe(II) produit à pH = 9.5 reste associée à la surface de l'oxyde dans l’échelle de temps des expériences. L’hydrosulfure a été converti en thiosulfate, polysulfures et, probablement, en soufre élémentaire, alors que le Fe2+ lixivié et le thiosulfate ont montré une production équimolaire pour pH ≥ 9.5. Un mécanisme de réaction détaillé pour l'oxydation anoxique d’hydrosulfure par le Fe/CeOx a été proposé pour expliquer la formation des produits ci-dessus et dont un modèle cinétique a été dérivé pour décrire les vitesses de lixiviation du Fe(II) et de consommation d’hydrosulfure. En conditions oxiques à pH [8.5-11.0], le Fe/CeOx oxyde l’hydrosulfure via une voie combinée hétérogène-homogène pour former les mêmes produits qu’en anoxique. L'oxygène accélère l'oxydation de l’hydrosulfure par le Fe/CeOx par un facteur de plus de trois en comparaison avec la réaction anoxique. L'oxygène assume un double rôle : d'abord, il ré-oxyde le fer de Fe(II) à Fe(III); en second lieu, il favorise l'oxydation de l`hydrosulfure vers les polysulfures et de ces-ci vers le thiosulfate, un produit non-volatile et non-odorant. L'oxydation du méthyle mercapture par Fe/CeOx a été étudiée aux différentes valeurs du pH [10.5-12] en conditions anoxique et oxique. Des conversions de mercapture allant jusqu'à 100% ont été obtenues en conditions oxiques bien que la conversion du mercapture se soit avérée tributaire de la quantité d'oxygène dissous. L'interférence avec l’hydrosulfure co-mélangé avec le mercapture a causé une inhibition dans la conversion des deux polluants. Une telle inhibition est due aux polysulfures naissants formés par l'oxydation de l’hydrosulfure. L'oxydation du méthyle mercapture par le système Fe/CeOx/O2 n'a pas affecté la capacité de régénération du Fe(III) de surface par l'oxygène dissous. Fe/CeOx semble être un matériau très prometteur pour un éventuel procédé de lavage-oxydatif pour l’élimination du méthyle mercaptan dans les émissions des industries papetières de type Kraft.
Hydrogen sulfide (H2S) and methyl mercaptan (MM) are the most abundant odor contaminants among the Total Reduced Sulfur (TRS) quartet (H2S, CH3SH, (CH3)2S, (CH3)2S2) contained in the Kraft mill atmospheric emissions. The association of TRS with sufficient oxygen could be taken advantage of, based on the iron chemistry, to convert TRS gases to odorless non-volatile products. The process uses Fe/Ce oxide-hydroxide (Fe/CeOx) slurried in alkaline solutions where both H2S and MM oxidative absorption (in the form of hydrosulfide and methyl mercaptide) is promoted. Capillary electrophoresis protocols were developed for the separation, identification and quantification of hydrosulfide, methyl mercaptide, polysulfides, thiosulfate, sulfate, sulfite and tetrathionate. The kinetics and mechanism of the anoxic reaction between hydrosulfide and Fe/CeOx were studied for pH [8.0-11.0] in a batch slurry reactor. Most of Fe(II) produced at pH = 9.5 remained associated with the oxide surface in the time-frame of the experiments. Hydrosulfide was converted into polysulfides, thiosulfate and, probably, elemental sulfur, while the leached Fe2+ and thiosulfate dovetailed equimolarly. A detailed reaction pathway of the anoxic oxidation of hydrosulfide by Fe/CeOx was proposed for explaining the formation of above products and whereof a kinetic model was derived to depict the Fe2+ leaching and hydrosulfide consumption rates. In oxic conditions at pH [8.5-11.0], Fe/CeOx will oxidize hydrosulfide via a combined heterogeneous-homogenous pathway to yield the same products as in anoxia. Oxygen enhanced Fe/CeOx-promoted hydrosulfide oxidation by more than a factor three when compared with anoxic reaction. Oxygen is believed to have a double role: first, it re-oxidizes iron from Fe(II) to Fe(III); second, it promotes oxidation of hydrosulfide to polysulfides which in turn transforms into non-volatile, non-odorous thiosulfate. The reaction between methyl mercaptide and Fe/CeOx was studied at different pH values [10.5-12] both in anoxic and oxic conditions. Up to 100% conversions of mercaptide were obtained in oxic conditions, though the mercaptide conversion was found to be tributary to the dissolved oxygen. Interference with hydrosulfide co-mixed with mercaptide caused an inhibition in the conversion for both pollutants, due to the incipient polysulfides formation. The oxidation of methyl mercaptide by the Fe/CeOx/O2 system did not affect the re-oxidative regeneration of surface Fe(III) by O2. Fe/CeOx appears to be a very promising material for a redox-scrubbing process targeting the TRS emissions from Kraft mills, via in situ regeneration of Fe(III) sites by O2.
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Oliveira, Pedro Henrique da Silva. "Influ?ncia da intensidade de aera??o na forma??o do floco de lodo ativado e na efici?ncia de remo??o de mat?ria org?nica." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15858.
Abstract:
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Previous issue date: 2014-07-24Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
In wastewater treatment, activated sludge systems have been a technology widely applied as secondary treatment. During this step, which has a strong biological aspect, it is necessary to introduce oxygen supply for the maintenance of metabolic activity of the bacteria through the aerators. Aeration devices are responsible for most of the energy consumption in this stage. In this background, the influence of three aeration intensities (atmospheric air flow 3.5, 7.0 and 10.5 L.min-1) and the concentration of dissolved oxygen (DO) on the dimension of activated sludge flocs as well as on the efficiency of organic matter removal were assessed using a traditional activated sludge system which was fed with synthetic domestic wastewater. Samples were taken weekly from the three units that make up the system feed, aeration and storage tank in order to verify the Chemical Oxygen Demand (COD). It was established the process efficiency through a comparison between the initial and final COD. Besides the parameters already mentioned, this monitoring work on activated sludge batch system was also observed by Mixed Liquor Suspend Solids (MLSS), Volatile Suspend Solids (VSS), pH and temperature measures. The results have showed a maximum removal efficiency around 75% in the first aeration sequence and approximately 85% for the second and third one. For the first aeration, the DO concentration remained higher than 3.0 mg.L-1 and a diameter range from 10 to 60 μm was observed. In the second e third sequence, the DO concentration remained higher than 4.0 mg.L-1 with a diameter range of 10 until 200 μm. Although the sequence 1 and 2 have presented similar performances for organic matter removal, the sequence 2 promoted a regular floc size distribution and with lower values of Sludge Volumetric Index (SVI) meaning a better flocculating ability. In addition, the results reaffirmed what the literature has reported: higher DO concentrations produce flocs with greater dimensions
No tratamento de ?guas residu?rias, os sistemas de lodos ativados t?m sido uma tecnologia largamente aplicada como tratamento secund?rio. Durante essa etapa, a qual possui uma caracter?stica fortemente biol?gica, ? necess?rio o fornecimento de oxig?nio para a manuten??o da atividade metab?lica das bact?rias atrav?s de aeradores. Os dispositivos de aera??o s?o respons?veis pela maior parte do consumo de energia ao longo dessa fase. Nesse contexto, a influ?ncia de tr?s intensidades de aera??o (vaz?o de ar atmosf?rico de 3,5, 7,0 e 10, 5 L.min-1) e a concentra??o de oxig?nio dissolvido (OD) sobre a dimens?o de flocos de lodo ativado, e bem como sobre a efici?ncia de remo??o foram avaliadas utilizando um sistema tradicional de lodos ativados alimentado com efluente dom?stico sint?tico. Amostras foram retiradas semanalmente das tr?s unidades que compunham o sistema tanque de alimenta??o, de aera??o e de armazenamento para verificar a Demanda Qu?mica de Oxig?nio (DQO). A efici?ncia do processo foi estabelecida atrav?s da compara??o entre a DQO inicial e final. Al?m dos par?metros j? mencionados, este trabalho de monitoramento do sistema de lodos ativados de bancada foi observado tamb?m por meio de medi??es de S?lidos em Suspens?o Totais (SST) e Vol?teis (SSV), pH e temperatura. Os resultados mostraram uma efici?ncia m?xima de remo??o de quase 75% na primeira sequ?ncia de aera??o e aproximadamente 85% para a segunda e terceira sequ?ncias. Para a primeira aera??o, a concentra??o de OD manteve-se maior que 3,0 mg.L-1 e uma faixa de di?metro de 10 a 60 μm foi observada, enquanto que na segunda e terceira sequ?ncia, a concentra??o de OD permaneceu superior a 4,0 mg.L-1 com uma faixa de di?metro de 10 a 200 μm. Embora a sequ?ncia 2 e 3 tenham apresentado, ambas, desempenhos similares para remo??o de mat?ria org?nica, a sequ?ncia 3 promoveu uma distribui??o de tamanho de flocos mais regular e com baixos valores de ?ndices Volum?tricos do Lodo (IVL), configurando em uma melhor habilidade de sedimenta??o. Em adi??o, os resultados reafirmam o que literatura tem relatado, maiores concentra??es de OD produzem flocos com maiores dimens?es
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Селянина, Т. В., and T. V. Selyanina. "Количественное определение натриевой соли 2-этилтио-6-нитро-1,2,4-триазоло-[5,1-c]-1,2,4-триазин-7-она дигидрата методом вольтамперометрии : магистерская диссертация." Master's thesis, б. и, 2020. http://hdl.handle.net/10995/94625.
Abstract:
Объектом исследования являлось вещество натриевая соль 2-этилтио-6-нитро-1,2,4-триазоло-[5,1-c]-1,2,4-триазин-7-она, дигидрат (УПИ-802). Цель работы: количественное определение лекарственного вещества натриевой соли 2-этилтио-6-нитро-1,2,4-триазоло-[5,1-c]-1,2,4-триазин-7-она дигидрата методом вольтамперометрии. В случае УПИ-802 наиболее полезным для количественного определения является сигнал электровосстановления нитрогруппы. Исследованы процессы восстановления нитрогруппы исследуемого вещества в водных и апротонных растворах с применением вольтамперометрии в условиях физического удаления растворенного кислорода и без удаления кислорода. Установлено, что скорость восстановления УПИ-802 контролируется диффузией, процесс восстановления нитрогруппы является необратимым и проходит в две стадии в буферном растворе Бриттона-Робинсона. Первая волна восстановления, которая лежит в области потенциалов -0,31 – (-0,8) В, соответствует присоединению 4 электронов. Обнаружено, что электровосстановление нитрогруппы протекает с предшествующим протонированием. Выбран оптимальный режим регистрации аналитического сигнала исследуемого вещества УПИ-802 на стеклоуглеродном электроде в условиях химического способа удаления растворенного кислорода – квадратно-волновой с амплитудой импульса 0,05 В, частотой импульса 35 Гц. Показана возможность применения толстопленочных углеродсодержащих электродов для определения исследуемого вещества методом квадратно-волновой вольтамперометрии. Выполнена оценка показателей качества методики анализа, таких как линейность, повторяемость (сходимость) и внутрилабораторная прецизионность.The object of the study was the substance 2-ethylthio-6-nitro-1,2,4-triazolo-[5,1-c]-1,2,4-triazin-7-one sodium salt dihydrate (UPI-802). Objective: quantification of 2-ethylthio-6-nitro-1,2,4-triazolo-[5,1-c]-1,2,4-triazin-7-one sodium salt dihydrate by the method of voltammetry. For UPI-802, the signal of electroreduction of a nitro group is the most useful for quantitative determination. The processes of the nitro group reduction of the test substance in aqueous and aprotic solutions was studied using voltammetry in conditions of physical removal of dissolved oxygen and without oxygen removal. It was established that the rate of reduction of UPI-802 is controlled by diffusion, the processes of reduction of the nitro group is irreversible and proceeds in two stages in a Britton-Robinson buffer solution. The first recovery wave, lying in the potential region of -0,31 - (-0,8) V, corresponds to the addition of 4 electrons. It was found that the electroreduction of the nitro group proceeds with previous protonation. The optimal mode for recording the analytical signal of the UPI-802 on the glassy carbon electrode was selected in conditions of chemical method for removing dissolved oxygen – square-wave with a pulse amplitude of 0,05 V and a pulse frequency of 35 Hz. The possibility of using thick-film carbon-containing electrodes to determine the test substance by the method of square-wave voltammetry was shown. The quality indicators of the analysis technique, such as linearity, repeatability (convergence) and intralaboratory precision, were evaluated.
Books on the topic "Dissolved oxygen Dam removal":
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Hazewinkel, R. R. O. Temperature and dissolved oxygen in the Oldman River following construction of the Oldman River Dam. Edmonton: Alberta Environment, 2007.
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Washington (State). Dept. of Ecology., ed. New oxygen criteria for fresh water, dam relicensing, and miscellaneous changes. [Olympia, Wash.]: Dept. of Ecology, 2002.
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Lewis, Yale. River dammed, river redeemed: Dam removal and salmon recovery in the Pacific Northwest. Seattle, WA: Mountaineers, 1999.
Book chapters on the topic "Dissolved oxygen Dam removal":
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Wagner, R., A. Mitschker, and T. Augustin. "Catalytic Removal of Dissolved Oxygen from Water." In Ion Exchange Advances, 144–50. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2864-3_19.
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Volkov, V. V. "Dissolved Oxygen (DO) in Water by Membrane Operations, Removal of." In Encyclopedia of Membranes, 571–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-44324-8_1039.
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Volkov, V. V. "Dissolved Oxygen (DO) in Water by Membrane Operations, Removal of." In Encyclopedia of Membranes, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-40872-4_1039-4.
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Hoshi, A., S. Miura, and Y. Nakagawa. "Removal of Dissolved Oxygen in Water for High-Power Resistive Magnet." In 11th International Conference on Magnet Technology (MT-11), 657–62. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0769-0_113.
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Jia, Aichen, and Huixue Yan. "Visualized Analysis of Spatial Distribution of Dissolved Oxygen and Nitrogen Removal Efficiency in Constructed Wetland." In Advances in Intelligent Systems and Computing, 781–89. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-95588-9_65.
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Di Marcantonio, Camilla, Amrita Bains, Agostina Chiavola, Naresh Singhal, and Maria Rosaria Boni. "Dissolved Oxygen Perturbations: A New Strategy to Enhance the Removal of Organic Micropollutants in Activated Sludge Process." In Frontiers in Water-Energy-Nexus—Nature-Based Solutions, Advanced Technologies and Best Practices for Environmental Sustainability, 371–73. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-13068-8_93.
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Engh, T. Abel, Christian J. Simensen, and Olle Wijk. "Removal Of Inclusions." In Principles of Metal Refining, 219–79. Oxford University PressOxford, 1992. http://dx.doi.org/10.1093/oso/9780198563372.003.0005.
Abstract:
Abstract The solubility of dissolved impurities in molten metals was seen in Chapter 2 to decrease with decreasing temperature. During solidification as the temperature drops and solubility decreases, impurities are precipitated as a second phase (non-metallic inclusions or intermetallic phases) in the metal. Oxides and sulphides in steel are examples of inclusions. Such particles are usually very harmful to the mechanical and other properties of the metal (Chapter 1). Therefore one attempts to keep the amount of impurities at low levels so that inclusions are not produced. Partly the approach is to employ stable refractories and a suitable protective slag. For instance, in steelmaking a basic reducing slag prevents the pick-up of oxygen from the atmosphere. Furthermore, allloy additions should be chosen that contain low levels of impurities and inclusions. Combined with these preventative measures dissolved impurity levels may be suppressed by the addition of elements with a high affinity for the impurity. An example of this is precipitation.
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Engh, T. Abel, Christian J. Simensen, and Olle Wijk. "Removal Of Dissolved Impurity Elements From Molten Metals." In Principles of Metal Refining, 171–218. Oxford University PressOxford, 1992. http://dx.doi.org/10.1093/oso/9780198563372.003.0004.
Abstract:
Abstract Impurities are already present in the ores and raw materials used in the extractive metallurgical processes. Impurities and inclusions are also introduced from refractories and atmosphere during the production of the metal and even in the refining processes. Thus oxygen, hydrogen, nitrogen, and carbon often enter the molten metal and affect the mechanical properties of the cast metal.For many extractive processes it is not practical and economic to try to protect the melt from the environment. Instead, the impurities are removed in the final refining operations. Basically in the refining stages we reverse the transfer of impurities. For instance, hydrogen and nitrogen are eliminated by gas purging and vacuum treatment.
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"Effect of dissolved oxygen on nitrate removal from drinking groundwater using rice wine." In Applied Mechanics and Civil Engineering VI, 215–22. CRC Press, 2017. http://dx.doi.org/10.1201/9781315229072-36.
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Kumarasamy, Gayathri, Sathishkumar Samiyappan, and Nirmaladevi Samiappan. "FUNCTIONALIZED POLYACRYLAMIDE/GRAPHITE COMPOSITES AS AN ADSORBENTS FOR THE DECOLOURISATION OF SYNTHETIC DYES AND DYEING INDUSTRY EFFLUENT FROM FABRIC PROCESSING UNITS." In Futuristic Trends in Chemical Material Sciences & Nano Technology Volume 3 Book 16, 18–26. Iterative International Publishers, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/v3bjcs16p1ch2.
Abstract:
In this study we have compared the decolourisation of dyeing industry effluents collected in fabric processing units and synthetic dyes like direct blue 2b, acid violet 17, reactive red M5B and methylene blue 9 from aqueous solution using functionalized polyacrylamide/graphite composites such as glucose grafted polyacrylamide/graphite, glucosamine grafted polyacrylamide/graphite and commercial activated carbon as adsorbents. The adsorption studies are performed by varying the experimental parameters like temperature, time, adsorbate concentration and adsorbent dose. The various physicochemical parameters of dyeing industry effluents such as colour, pH, conductivity, total dissolved solids, hardness, alkalinity, chloride, sulphate, dissolved oxygen, chemical oxygen demand and bio-chemical oxygen demand of the effluents are analyzed before and after adsorption by the standard methods. It is observed that the synthesized adsorbents show more efficiency towards the removal of synthetic dyes from aqueous solution than the decolourisation of dyeing industry effluent. The amount of adsorbents required and cost analysis to treat 10 M3 of effluent is also studied and compared with commercial activated carbon.
Conference papers on the topic "Dissolved oxygen Dam removal":
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PALANIANDY, PUGANESHWARY, MOHD NORDIN ADLAN, and HAMIDI ADBUL AZIZ. "DISSOLVED AIR FLOTATION (DAF) PROCESS FOR COLOUR AND CHEMICAL OXYGEN DEMAND (COD) REMOVAL IN LANDFILL LEACHTE TREATMETN." In Proceedings of the International Conference on CBEE 2009. WORLD SCIENTIFIC, 2009. http://dx.doi.org/10.1142/9789814295048_0030.
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Cheng, Xiangju, Xuewei Chen, and Yongcan Chen. "Numerical Simulation of Dissolved Oxygen Concentration in the Downstream of Three Gorges Dam." In World Environmental and Water Resources Congress 2009. Reston, VA: American Society of Civil Engineers, 2009. http://dx.doi.org/10.1061/41036(342)293.
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Lehmann, Marc, Katerina Lepkova, Thunyaluk Pojtanabuntoeng, Varun Ghodkay, Annamaria Greenwood, Susumu Hirano, and Toshiyuki Sunaba. "Use of Oxygen Scavenger in Well Safety Valve Balancing Operations." In Offshore Technology Conference Asia. OTC, 2022. http://dx.doi.org/10.4043/31509-ms.
Abstract:
Abstract Monoethylene glycol (MEG) is often used to reduce the differential pressure across well valves so that they can be opened without damage. This MEG ultimately commingles with production fluids and if not deoxygenated contributes to the overall content of dissolved oxygen that may be seen by a receiving production facility. Normally, the dissolved oxygen levels would be removed to insignificant levels during fluid transport. Since the corrosion reactions sequester the oxygen as the fluids are exposed to less noble materials of construction, such as carbon steel. However, in facilities that utilise corrosion resistant alloys (CRA) the residual dissolved oxygen level can be so significant that it warrants reduction using oxygen scavengers. This paper reports on corrosion studies that illustrate the consequence of dissolved oxygen levels being carried through to a MEG reclamation unit constructed of CRA, and laboratory and field validation studies on the use of a bisulfite-based scavenger for removal of oxygen in 90wt% MEG used for equalising pressure of Subsurface Safety Valves.
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Culbertson, Adam, Lily Wetterlin, Hannah McIlwain, and Christopher Johnson. "EFFECTIVENESS OF BEAVER DAM ANALOGS AS A RESTORATION STRATEGY TO MITIGATE INCREASED WATER TEMPERATURES AND DECREASED DISSOLVED OXYGEN." In 72nd Annual GSA Rocky Mountain Section Meeting - 2020. Geological Society of America, 2020. http://dx.doi.org/10.1130/abs/2020rm-346621.
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Zanfang, Jin, Jin Mantong, Li Feili, Pan Zhiyan, Wan Yu, Chen Yingxu, and Huang Yanhong. "Effect of Dissolved Oxygen on Removal of Nitrate in Laboratory Columns Packed with Solid Organic Carbon." In 2011 International Conference on Computer Distributed Control and Intelligent Environmental Monitoring (CDCIEM). IEEE, 2011. http://dx.doi.org/10.1109/cdciem.2011.405.
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Seymour, Ian, Benjamin O'Sullivan, Pierre Lovera, James F. Rohan, and Alan O'Riordan. "Removal of Dissolved Oxygen Interference in the Amperometric Detection of Monochloramine Using a pH Control Method." In 2019 IEEE SENSORS. IEEE, 2019. http://dx.doi.org/10.1109/sensors43011.2019.8956674.
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Gao, Pin, Zhen-Hong Liu, Gang Xue, Meihua Zhou, Lu Liu, Yun-Zhi Zhao, and Dan Han. "Modeling Dissolved Oxygen Effects on Biological Nutrient Removal in a Sequencing Batch Reactor with Activated Sludge Model 2d." In 2009 3rd International Conference on Bioinformatics and Biomedical Engineering (iCBBE 2009). IEEE, 2009. http://dx.doi.org/10.1109/icbbe.2009.5163073.
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Spadaccini, Louis J., and He Huang. "On-Line Fuel Deoxygenation for Coke Suppression." In ASME Turbo Expo 2002: Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30071.
Abstract:
Fuel deoxygenation is being developed as a means for suppressing autoxidative coke formation in aircraft fuel systems, thereby increasing the exploitable cooling capacity of the fuel, enabling major increases in engine operating temperature and cycle efficiency. Reduced maintenance is an added benefit. A prototype membrane filter module for on-line removal of dissolved oxygen, which would otherwise react to form coke precursors, was constructed and successfully demonstrated. The fuel flows over the membrane, while oxygen diffuses through it at a rate that is proportional to the difference in oxygen partial pressures across the surface. Tests were conducted over a range of fuel flow rates (residence times) and temperatures. The filter was operated with air-saturated jet fuel for several hours at a steady-state condition, verifying the capability to remove essentially all of the dissolved oxygen (to <1 ppm) and proving the viability of the concept. A convincing demonstration of coke suppression was performed when air-saturated (normal) and deoxygenated jet fuels were tested in a standard ASTM heated tube apparatus at wall temperatures as high as 850 F. With deoxygenated fuel, there was a dramatic reduction (more than an order of magnitude) in coke deposition relative to air-saturated Jet A, which will allow the maximum fuel temperature to be increased by more than 200 F, doubling the available heat sink. Moreover, deoxygenated Jet A was shown to perform as well as JP-7, the Air Force’s highest thermal stability fuel. An analytical model for oxygen permeation through the membrane was formulated, and used in conjunction with the test data to estimate the filter size required for a practical (i.e., low-volume/high-flowrate) deoxygenator.
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ŽIBIENĖ, Gražina, and Alvydas ŽIBAS. "WATER QUALITY AND WASTE CONTAMINATION STUDY IN CATFISH REARING RECIRCULATING AQUACULTURE SYSTEM." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.015.
Abstract:
In this article we analyse catfish rearing conditions in recirculating aquaculture systems (RAS). Based on research, performed by scientists from different countries, we evaluated optimal water parameter values for catfish rearing. African catfish growing process and with it associated factors were researched in JC ,,Šamas“. The amount of dissolved oxygen (on average 4,53 mg/l) in the rearing basin is adequate for the catfish to feel comfortable and for biomass growth. Water temperature only varies slightly – the average water temperature is 23,30C. The ideal pH for rearing fish in RAS is 7.0. Many aquaculture species continue to feel comfortable in pH boundaries of 6.5-8.5. In the samples, taken from catfish rearing system, the pH varied from 5.58 to 6.63. Such acidic water decreases the effectiveness of biological filter, but also decreases the toxic effect of excreted ammonia on the fish. Only a small amount of suspended solid is present in the samples, which means that they are being removed properly. The average amount of ammonia nitrogen in the water basins in analysed catfish rearing systems is 1,171 mg/l. The analysed water samples presented an average nitrite amount of 0,974 mg/l. The recommended amount of nitrites for catfish is less than 0.5 mg/l. The analysed samples presented relatively high nitrate values – from 412 to 495 mg/l. In order to decrease the concentration of accumulated nitrates it is required to change no less than 10% of total system water volume every day. The index of consumed biochemical oxygen corresponds to the requirements for water quality in RAS
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Watanabe, Yutaka, Kiwamu Sue, and Hiroshi Abe. "Effects of Cr Content and Environmental Factors on FAC Rate of Carbon Steels." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-78126.
Abstract:
Combined effects of Cr content and environmental factors, pH and dissolved oxygen concentration, on removal rate of carbon steels due to flow accelerated corrosion have been examined by experiments. The effects of environmental factors on FAC rate have been attempted to interpret based on oxide solubility, which has been precisely evaluated by separate experiments and numerical estimations. pH dependency of the FAC rate has been found to be directly related to solubility of magnetite. Cr content holds a strong impact on the FAC rate regardless of pH values from 6.84 to 10.4. Addition of 1% Cr to a carbon steel reduces the FAC rate by one order of magnitude under the environmental conditions, where magnetite forms. Addition of oxygen up to 1200ppb changes the oxide from magnetite to hematite, resulting in significant improvement in corrosion resistance. Oxide film characteristics, e.g. compositional distributions and types of oxide compound, have been also examined and their correlation to the FAC rate has been discussed.
Reports on the topic "Dissolved oxygen Dam removal":
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CORPS OF ENGINEERS OMAHA NE. Low Dissolved Oxygen Levels in Summer Powerplant Discharges from Fort Randall Dam, South Dakota. Fort Belvoir, VA: Defense Technical Information Center, October 2010. http://dx.doi.org/10.21236/ada581197.
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Weissinger, Rebecca. Status and trends of springs at Hovenweep National Monument, 1999–2021. Edited by Alice Wondrak Biel. National Park Service, August 2023. http://dx.doi.org/10.36967/2294373.
Abstract:
Water is a scarce, but vital, resource at Hovenweep National Monument (NM). The National Park Service has prioritized long-term monitoring of water resources at the monument through a variety of programs and indicators since 1999. The purpose of this report is to evaluate water-quantity and water-quality data collected at long-term monitoring sites in Hovenweep NM from 1999 to 2021 for trends over time, and to summarize site-characterization data for currently monitored locations. Data are available for three active monitoring stations—Square Tower Spring, Hackberry Pool, and Goodman Point Spring—and three discontinued monitoring stations—Cajon Pool, Upper Hackberry Spring (Spring #4), and Horseshoe Spring. Water resources at Hovenweep NM have exhibited many trends over the past two decades. Pool levels at both Square Tower Spring and Hackberry Pool went up, with a step increase shown in 2016 (after no sampling in 2014–2015). In contrast, flow decreased by more than half at Goodman Point Spring and ceased at Upper Hackberry Spring (Spring #4). Flow at Horseshoe Spring also decreased, although the period of record at this site was very short. Both Upper Hackberry Spring (Spring #4) and Horseshoe Spring were removed from the monitoring rotation because flows were increasingly absent or too low to measure. Pool-level dynamics and water chemistry at Cajon Pool are characteristic of precipitation-derived water rather than groundwater; this site was removed from the monitoring rotation because it was not a good indicator of groundwater conditions. The water chemistry in both Square Tower Spring and Hackberry Pool changed significantly, but in opposite directions. Square Tower Spring had increasing total dissolved solids (TDS) and specific conductance, with all major ions showing increases over time. Hackberry Pool had decreases in TDS and most major ions through 2010, when water-chemistry lab analyses were suspended due to logistical constraints. Specific conductance continued to decrease at Hackberry Pool through 2021. The reasons for these changes are unknown. Increases in major ions at Square Tower Spring are unlikely to be related to oil and gas development in the region. Decreases in major ions at Hackberry Pool may reflect an increase in the amount of water that is entering the pool from rain and snowmelt rather than groundwater at this site. Water-quality parameters at Goodman Point Spring have remained stable. While the causes of trends in water chemistry at these sites are likely natural, the small quantities of water and harsh water-quality conditions make these sites poor habitat for aquatic life. Groundwater is naturally low in dissolved oxygen—but the dissolved-oxygen concentrations in the two pools are persistently low, sometimes falling to near zero in the summer. Water temperatures also warm in conjunction with air temperatures, with temperatures as warm as 18°C in the pools and 19°C in Goodman Point Spring. Traditionally, Puebloan cultures would have managed these small water resources to promote infiltration and retention of precipitation and to remove sediment and debris. Decreases in flow and increasing vegetation stress are likely tied to increasing air temperatures and long-term drought conditions across the region. The namesake hackberry trees at Hackberry Pool and nearby sites have shown increasing drought stress. Regionally, the underlying Dakota aquifer that feeds springs at the monument was relatively stable from 2008 to 2017, with decreasing levels from 2018 to 2021. Overall, the most concerning trends observed at springs in Hovenweep NM are likely due to climate change. Increasing air temperature threatens springflow and spring-associated vegetation through increased evapotranspiration. While pool levels have increased, recent decreases in the regional Dakota aquifer raise concerns about the stability of pools in the future. Managers could consider the potential benefits and risks of: Prioritizing protections and actions at Square Tower Spring, which has been the most resilient site at the monument in persistence of surface water and vegetation health during extreme drought. Implementing potential climate-adaptation actions that could improve groundwater infiltration upgradient of spring sites. This could include rehabilitating traditional structures to slow the flow of surface water. Implementing traditional management techniques that could increase dissolved-oxygen concentrations in the spring pools. Increasing invasive-plant removal efforts at Goodman Point Spring, which had the greatest number and cover of invasive-plant species of the three currently monitored locations. Developing interpretive stories about water-management techniques and the role of climate change in creating drought stress on iconic hackberry trees.
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Bowles, David, Michael Williams, Hope Dodd, Lloyd Morrison, Janice Hinsey, Tyler Cribbs, Gareth Rowell, Michael DeBacker, Jennifer Haack-Gaynor, and Jeffrey Williams. Protocol for monitoring aquatic invertebrates of small streams in the Heartland Inventory & Monitoring Network: Version 2.1. National Park Service, April 2021. http://dx.doi.org/10.36967/nrr-2284622.
Abstract:
The Heartland Inventory and Monitoring Network (HTLN) is a component of the National Park Service’s (NPS) strategy to improve park management through greater reliance on scientific information. The purposes of this program are to design and implement long-term ecological monitoring and provide information for park managers to evaluate the integrity of park ecosystems and better understand ecosystem processes. Concerns over declining surface water quality have led to the development of various monitoring approaches to assess stream water quality. Freshwater streams in network parks are threatened by numerous stressors, most of which originate outside park boundaries. Stream condition and ecosystem health are dependent on processes occurring in the entire watershed as well as riparian and floodplain areas; therefore, they cannot be manipulated independently of this interrelationship. Land use activities—such as timber management, landfills, grazing, confined animal feeding operations, urbanization, stream channelization, removal of riparian vegetation and gravel, and mineral and metals mining—threaten stream quality. Accordingly, the framework for this aquatic monitoring is directed towards maintaining the ecological integrity of the streams in those parks. Invertebrates are an important tool for understanding and detecting changes in ecosystem integrity, and they can be used to reflect cumulative impacts that cannot otherwise be detected through traditional water quality monitoring. The broad diversity of invertebrate species occurring in aquatic systems similarly demonstrates a broad range of responses to different environmental stressors. Benthic invertebrates are sensitive to the wide variety of impacts that influence Ozark streams. Benthic invertebrate community structure can be quantified to reflect stream integrity in several ways, including the absence of pollution sensitive taxa, dominance by a particular taxon combined with low overall taxa richness, or appreciable shifts in community composition relative to reference condition. Furthermore, changes in the diversity and community structure of benthic invertebrates are relatively simple to communicate to resource managers and the public. To assess the natural and anthropo-genic processes influencing invertebrate communities, this protocol has been designed to incorporate the spatial relationship of benthic invertebrates with their local habitat including substrate size and embeddedness, and water quality parameters (temperature, dissolved oxygen, pH, specific conductance, and turbidity). Rigid quality control and quality assurance are used to ensure maximum data integrity. Detailed standard operating procedures (SOPs) and supporting information are associated with this protocol.