Dissertations / Theses: 'Purification of Air'

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Gustafsson, Anders. "Performance monitoring of systems for air purification." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-246148.

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Wastewater treatment plants (WWT P ) are often the cause of malodor. The com-pounds which are the main causes of the odor is hydrogen sulﬁde (H2S), ammonia (NH3), mercaptans (RSH) and volatile organic compounds (V OC) [1]. The odorous air can be analyzed to determine the concentration of the odorants. The odorous can also be analyzed by measuring the odor. The odor is measured, a test panel of people smells the odorous air and determines how many times greater the concentration of the odorants is compared to the odor threshold which is the concentration at which a compound or a mixture is detectable by smell [3].Measurements were done at three systems for air puriﬁcation at three diﬀerent locations, the Vimmerby WWT P , the Alvim WWT P and Renova’s biological waste treatment facility in Gothenburg. The odor was measured at the inlet and the outlet and the concentration of H2S and ozone (O3) were measured at all the sampling points of the systems. The system at Vimmerby consisted of three CIF s followed by an UV-reactor and an AC-reactor. In Alvim there were two system which used UV and AC. The system at Renova consisted of a barrier ﬁlter followed by UV and AC.The system at the Vimmerby WWT P had a conversion rate between 87-97% of H2S. The CIF s had conversions between 50-64% of the H2S. H2S was not detected at any of the other systems. O3 was only detected at Renova where ground level O3 was present at the inlet, 0.16 ppm. The concentration increased to 0.20 ppm after the UV-reactor. The activated carbon could adsorb all the incoming O3.The odor at the Vimmerby WWT P was determined to 27500 Ou/m3 at the inlet and 19071 Ou/m3 at the outlet. The odor conversion over the system was 31%. The odor conversion at the Alvim WWTP was 99.8%. With an odor of 5490 Ou/m3 at the inlet and 11 Ou/m3 at the outlet. The ingoing air at the system at Renova had an odor of 434 Ou/m3 and was reduced to 36 Ou/m3 at outlet. The odor conversion at Renova was 92%.To increase the accuracy of the measurements he time between the sampling and measurements should have been minimized. The test panels should also have been larger and the panelists should have been screened in advance, so results from panelists which were over and under sensitive to odors were not included in the ﬁnal results.

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Yun, Ji Sub. "Purification of Indoor Air Pollutants Utilizing Hydrophobic Adsorbents." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/41613.

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Sick building syndrome (SBS) is a particular concern in places with inadequate ventilation and frequently attributed to chemical contaminants such as volatile organic compounds (VOCs)released from indoor sources that are frequently encountered in everyday life such as adhesives, carpeting, upholstery, manufactured wood products, copy machines, pesticides, cleaning agents inside buildings, plumbing vents, and painting. Furthermore, it is a major issue for modern human beings who spend most of their time indoors or must stay indoors for self-isolation due to special circumstances such as the coronavirus disease-19 (COVID-19) pandemic that occurred in 2019 and 2020. Main indoor VOCs are trichloroethylene (TCE), benzene, toluene, and para-xylene (p-xylene). In general, these compounds are not present in indoor spaces at acute concentrations, but prolonged exposure to these compounds can have chronic health effects such as allergic sensitization, increased cancer risks, and respiratory diseases. In this study, the adsorption process with various advantages has been applied to remove VOC’s using commercially available hydrophobic adsorbents. The hydrophobic adsorbents can contribute to reducing the possibility of chemical adsorption (chemisorption) of moisture from the air, which can decrease the capacity of adsorbent by clogging the pores. The adsorption of these major VOCs was investigated in this work for three major types of industrial hydrophobic adsorbents: activated carbons, zeolites, and polymer. This study will show the investigation into finding the most promising hydrophobic adsorbent for removal of TCE, benzene, toluene, and p-xylene, which are the main VOCs found indoors. The promising hydrophobic adsorbent has been determined by comparing Henry’s law constants and heat of adsorption values for the different adsorbents, which were estimated by using a concentration pulse chromatographic technique by utilizing a gas chromatograph equipped with a flame ionization detector. For all adsorbents, Henry’s law constants at room temperature of p-xylene were always the highest followed by toluene, benzene, and TCE. For all adsorbates, Henry’s law constants at room temperature of AC BPL and HiSiv 3000 were higher than the other hydrophobic adsorbents. For a developing modern society dealing with a pandemic, this study can contribute to producing the optimized gas masks and indoor filters for the removal of indoor air pollutants, which can help people who suffer from SBS. It can also help society for taking preventative actions towards dealing with SBS.

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Zhang, Yangyang. "Modeling and Design of Photocatalytic reactors for Air Purification." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4621.

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Photocatalysis is a promising technique for the remediation of indoor air pollution. Photocatalysis utilizes semiconductor photocatalysts (such as TiO2 or ZnO) and appropriate light to produce strong oxidizing agents (OH*) that are able to break down organic compounds and inactivate bacteria and viruses. The overall goal of the research is to develop an efficient photocatalytic reactor based on mass transfer for indoor air purification. This study has focused on the enhancement of the effectiveness of the photocatalytic process by the introduction of artificial roughness on the reactor catalyst surface. The major effect of artificial roughness elements on the catalytic surface is to create local wall turbulence and enhance the convective mass transfer of the contaminants to the catalyst surface and thus lead to an increase in the effectiveness of photocatalysis. Air flow properties in a model photoreactor channel with various roughness patterns on the interior wall surface were theoretically investigated. The optimum shapes, sizes, and arrangements of roughness were determined for the maximum enhancement of turbulence intensity in the channel. The possible order of photocatalytic reactor performance for various roughness patterns was also determined. In order to verify the theoretical analysis results, experimental studies were carried out. A plate type photocatalytic reactor was designed and fabricated on the basis of the theoretical results. It was determined that the photocatalytic reactor performance is greatly improved with various rough catalyst surfaces. The experimental results verified the theoretical results. The relationship between the overall reaction rate constant (k) of the reactor and the magnitude of the turbulence intensity was found out. An empirical correlation expression was also proposed. This is the first study of the effect mass transfer in a rough catalytic surface for photocatalytic reactor. Photocatalyst development has also been studied. Zinc oxide (ZnO) and iron doped zinc oxide (ZnO/Fe) nanowires were synthesized on glass substrates through a conventional hydrothermal method. The photocatalytic activities under ultraviolet (UV) light and white light irradiation were separately investigated. The ZnO/Fe nanowires exhibited an enhanced photocatalytic activity as compared to ZnO nanowires regardless of the type of contaminants and light sources.

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Lam, Chun-wai Ringo, and 林俊偉. "Development of photocatalytic oxidation technology for purification ofair and water." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38572382.

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Lam, Chun-wai Ringo. "Development of photocatalytic oxidation technology for purification of air and water." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38572382.

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Niu, Hejingying, and 牛何晶英. "Nitric oxide removal by wastewater bacteria in a biotrickling filter." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50533885.

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Nitric oxide (NO) is one of the most important air pollutants in atmosphere mainly emitted from combustion exhaust gas. In this research, a biotrickling filter was designed and operated to remove this pollutant from an air stream using bacteria extracted from the sewage sludge of a municipal sewage-treatment plant. The bacteria were cultured and enriched by either petri dish’s cultivation or liquid cultivation. The adsorption capacity of the ceramic material, which was used as the packing material, was determined to be 34 g-NO/L under 37℃. However, the saturated adsorption capacity of the packing material with the recycling solution is 236 mg-NO/L under the operation temperature 37℃.The result suggested that the microporous structure of the ceramic material not the humidity is the main contributor to the ceramic material adsorption capacity. Both the ceramic material adsorption capacity and the removal capacity of the liquid were limited and saturated in 540 min and 2 min operation, respectively. To obtain the best operation conditions for the biotrickling filter, orthogonal experiments (L9 (34)) were designed. The experimental data were analyzed by the signal to noise (S/N) ratio and ANOVA. The optimal conditions of the biotrickling filter occurred at a temperature of 40℃, a pH of 8.00.05 and a chemical oxygen demand (COD) of 165 mg/L in the recycled water with no oxygen in the system. Inlet oxygen concentration was found to be the most significant factor of the biotrickling filter that has a significant negative effect on the NO removal efficiency. The DNA sequencing of four clones of bacteria showed 93-98% similarity to Pseudomonas mendocina strain. This strain has been analysed by full gene sequencing and proved to be a brand-new strain named as Pseudomonas mendocina DLHK. This strain can transfer nitrate to organic nitrogen. This result indicated the assimilation nitrogen process in this system and suggested that the main nitrogen removal capacity in this system was through biological function. Through the isotope experimental analysis, two intermediate products (15NO and 15N2O) have been found during the biological process of the system by using quantitative gas analysis (QGA). These results indicated the denitrification function in this biotrickling filter. A model was developed to explain the biological process in the biotrickling filter. The averaged error of the measured and modeled data is -0.047. The standard deviation of the error is 0.039. The model prediction is in good agreement with the experimental data, particularly at small packing height. Most NO removal capacity was achieved at the first 5 cm packing material. The effects of the axial interstitial velocity and the biofilm coverage to the NO elimination were studied by the model that provided a basic for the design of a biotrickling filter. The biotrickling filter could be used for exhaust gases treatment. The assimilation function in the biological system could be another way to utilize the nitrogen component in the waste gas from harmful to benign nature. The isotope labeling technology is a new method to detect gas components for complex gas samples.
published_or_final_version
Mechanical Engineering
Doctoral
Doctor of Philosophy

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WALTER, RICHARD MARIE-CLOTILDE. "Methodes de reduction de l'allergene majeur du chat fel d i : comparaison de quatre systemes d'epuration de l'air." Strasbourg 1, 1995. http://www.theses.fr/1995STR15020.

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Abussaud, Basim Ahmed. "Wet air oxidation of benzene." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103362.

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Processing of petrochemical compounds produces a large amount of wastewater. This wastewater consists of toxic (hazardous) materials that can not be discharged to the environment without treatment. As restrictive environmental constraints increase, new technologies are needed to treat those toxic materials before discharging them to the environment. Wet Air Oxidation (WAO) is one of these new methods.
This study casts light on the effect of initial pH on the WAO of benzene at different temperatures and pressures. It was found that at pH 6, a temperature of 260°C and a partial pressure of oxygen of 1.38 MPa around 97% degradation was achieved in one hour. When the initial pH was lowered to 4 more than 90% degradation was achieved at 220°C and PO2 of 1.38 MPa in only 15 minutes.` It was concluded that the higher the temperature the better the benzene degradation, and the faster benzene degradation has been obtained with the increasing partial pressure of oxygen. The main intermediates were acetic acid and formic acid.
Furthermore, it was found that the degradation of benzene can be further enhanced in the presence of phenol. The main reason can be attributed to the effect of the free radicals generated from the fast phenol degradation. A simplified pathway for oxidation of benzene was proposed.

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Clausse, Benoît. "Adsorption/coadsorption de composés organochlorés par une faujasite Y hydrophobe/organophile dans un contexte de dépollution de l'air et de l'eau." Dijon, 1997. http://www.theses.fr/1997DIJOS006.

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L’adsorption par une faujasite Y desaluminée (Si/Al>100) du dichlorométhane (DCM), 1,2-dichloroethane (DCE), trichloroéthène et tétrachloréthène en phase gazeuse pure ou en mélange, ainsi que l'adsorption des composes DCM et DCE en solution aqueuse ont été étudiées dans un contexte de purification d'effluents gazeux ou aqueux pollués. Les résultats montrent que l'adsorption d'un composé à partir d'une solution aqueuse ou d'un mélange gazeux se réduit à un équilibre entre deux phases non miscibles, la zéolithe jouant le rôle de solvant hydrophobe. Une bonne corrélation est obtenue entre la capacité d'adsorption, l'enthalpie d'adsorption et le coefficient de diffusion en fonction du remplissage. Lors de l'adsorption compétitive de plusieurs composés, la sélectivité est toujours en faveur du composé le moins volatil. Comme le prévoit l'étude thermodynamique, la séparation par adsorption sur une faujasite Y desaluminée est comparable à une distillation, aucun effet de structure n'étant mis en évidence lors du trace des courbes de perçage. Au début de ces courbes, un pseudopalier, dont la concentration limite est celle du point d'inflexion des isothermes, est mis en évidence: c'est une limite thermodynamique au-dessous de laquelle la dépollution n'est plus envisageable. Il est alors possible de prédire le comportement de l'adsorption compétitive à partir des propriétés physico-chimiques des composés purs. La régénération de la faujasite Y nécessite une température d'autant plus basse et un temps d'autant plus court que le compose est plus volatil, et, les résultats obtenus sur site industriel sont en accord avec les recherches fondamentales. Sur le plan appliqué, la présence de ce pseudopalier est d'une grande importance car sa valeur de concentration ne doit pas être supérieure aux limites de rejet imposées. Pour supprimer ou abaisser cette concentration limite, il est nécessaire d'utiliser un adsorbant dont l'isotherme d'adsorption se rapproche du type I, que seront des faujasites de rapport Si/Al peu élevé ou des zéolithes se structure différente.

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Mirzaei, Ali Akbar. "Low temperature carbon monoxide oxidation using copper containing catalysts." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266493.

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Zazueta, Ana Luis Loo. "Modeling, design and evaluation of a multi-plate photocatalytic reactor for air purification." Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605585.

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Indoor air pollution is a persistent problem found not only in buildings but . also in transportation vehicles, aircrafts and many other confined spaces. Photocatalytic air cleaning devices, in combination with source control and ventilation appears to be a promising method to reduce volatile organic compounds (VOCs) levels, which are among the most abundant indoor air pollutants. A major challenge this technology faces, is poor catalyst illumination efficiency. In general, effective photon utilization is a critical factor in determining the economic feasibility of a particular photocatalytic reactor design. A deficient use of light within a photocatalytic reactor will inherently lead to high operational costs, which in turn, will prevent the reactor to be implemented especially in cases in which catalyst activity is low. Consequently, the analysis of the radiation field in photocatalytic reactors is an essential step towards the optimization of photocatalytic air cleaners. This study focuses on the analysis and optimization of the geometry and radiation field in a multi-plate photocatalytic reactor (MPPR) irradiated by cylindrical UV lamps orthogonal to the plates, a reactor virtually not studied before. The MPPR aims to provide not only high light utilization, but also low pressure drop while treating large volumes of air. The MPPR presents a large photocatalyst surface area as well as a modular design, which facilitates scale up. All these characteristics could make the MPPR a costeffective alternative for indoor air remediation. The optimum design was validated by the oxidation of toluene in a humidified air stream. In addition, the performance of the reactor was evaluated with close to real concentrations using mixtures of trichloroethylene, ethanol, acetone, hexane and toluene.

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Stanley, Anthony Wayne. "An investigation of the suitability of DC corona discharges for air purification systems." Thesis, Cranfield University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304398.

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Smith, Francis Lee. "Pilot-scale Development of Trickle Bed Air Biofiltration Employing Deep Biofilms, for the Purification of Air Polluted with Biodegradable VOCs." University of Cincinnati / OhioLINK, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1034206999.

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Alkhudhiri, Abdullah Ibrahim. "Treatment of saline solutions using air gap membrane distillation (AGMD)." Thesis, Swansea University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678440.

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Land, Eva Miriam. "Photocatalytic degradation of NOX, VOCs, and chloramines by TiO2 impregnated surfaces." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34857.

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Experiments were conducted to determine the photocatalytic degradation of three types of gas-phase compounds, NOX, VOCs, and chloramines, by TiO2 impregnated tiles. The oxides of nitrogen NO and NO2 (NOx) have a variety of negative impacts on human and environmental health ranging from serving as key precursors for the respiratory irritant ozone, to forming nitric acid, which is a primary component of acid rain. A flow tube reactor was designed for the experiments that allowed the UV illumination of the tiles under exposure to both NO and NO2 concentrations in simulated ambient air. The reactor was also used to assess NOx degradation for sampled ambient air. The PV values for NO and NO2 were 0.016 cm s-1 and 0.0015 cm s-1, respectively. For ambient experiments a decrease in ambient NOx of ~ 40% was observed over a period of roughly 5 days. The mean PV for NOx for ambient air was 0.016 cm s-1 and the maximum PV was .038 cm s-1. Overall, the results indicate that laboratory conditions generally simulate the efficiency of removing NOx by TiO2 impregnated tiles. Volatile organic compounds (VOC's) are formed in a variety of indoor environments, and can lead to respiratory problems (US EPA, 2010). The experiments determined the photocatalytic degradation of formaldehyde and methanol, two common VOCs, by TiO2 impregnated tiles. The same flow tube reactor used for the previous NOX experiments was used to test a standardized gas-phase concentration of formaldehyde and methanol. The extended UV illumination of the tiles resulted in a 50 % reduction in formaldehyde, and a 68% reduction in methanol. The deposition velocities (or the photocatalytic velocities, PV) were estimated for both VOC's. The PV for formaldehyde was 0.021 cm s-1, and the PV for methanol was 0.026 cm s-1. These PV values are slightly higher than the mean value determined for NO from the previous experiments which was 0.016 cm s-1. The results suggest that the TiO2 tiles could effectively reduce specific VOC levels in indoor environments. Chlorination is a widespread form of water disinfection. However, chlorine can produce unwanted disinfection byproducts when chlorine reacts with nitrogen containing compounds or other organics. The reaction of chlorine with ammonia produces one of three chloramines, (mono-, di-, and tri-chloramine). The production of chloramines compounds in indoor areas increases the likelihood of asthma in pool professionals, competitive swimmers, and children that frequently bath in indoor chlorinated swimming pools (Jacobs, 2007; Nemery, 2002; Zwiener, 2007). A modified flow tube reactor in conjunction with a standardized solution of monochloramine, NH2Cl, determined the photocatalytic reactions over the TiO2 tiles and seven concrete samples. The concrete samples included five different concrete types, and contained either 5 % or 15 % TiO2 by weight. The PV for the tiles was 0.045 cm s-1 for the tiles manufactured by TOTO Inc. The highest PV from the concrete samples was 0.054 cm s-1. Overall the commercial tiles were most efficient at reducing NH2Cl, compared to NOX and VOC compounds. However, the concrete samples had an even higher PV for NH2Cl than the tiles. The reason for this is unknown; however, distinct surface characteristics and a higher concentration of TiO2 in the concrete may have contributed to these findings.

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Charalambous, Charithea. "Temperature swing adsorption process for carbon dioxide capture, purification and compression directly from atmospheric air." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33311.

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Many reports, scientific papers, patents, and scientific news investigate the feasibility and affordability of direct carbon dioxide capture from the atmospheric air (DAC). Since carbon dioxide (CO2) is extremely diluted in the atmosphere, large volumes of air have to be handled to capture comparable amounts of CO2. Therefore, both the energy consumption and the plant size are expected to be 'prohibitive'. On the other hand, some analyses have shown that DAC is feasible and can become affordable with essential research and development. DAC has been regarded as an optional bridging or a transitional technology for mitigating CO2 emissions in the medium-term. Priorities include investing in renewable and low-carbon technologies, efficiency and integration of energy systems, and realisation of additional environmental benefits. A heavy reliance on negative emission technologies (NETs), and consequently DAC, may be extremely risky as NETs interact with a number of societal challenges, i.e. food, land, water and energy security. Although, "... capturing carbon from thin air may turn out to be our last line of defence, if climate change is as bad as the climate scientists say, and if humanity fails to take the cheaper and more sensible option that may still be available today" MacKay (2009). Certainly, more research is necessary to bring down both cost and energy requirements for DAC. This work firstly predicts the adsorption equilibrium behaviour of a novel temperature swing adsorption process, which captures carbon dioxide directly from the air, concentrates, and purifies it at levels compatible to geological storage. The process consists of an adsorption air contactor, a compression and purification train, which is a series of packed beds reduced in size and connected in-line for the compression and purification purposes, and a final storage bed. The in-line beds undergo subsequent adsorption and desorption states. The final desorbed stream is stored in a storage bed. This cyclic process is repeated for a number of times imposed by the required purity and pressure in the final bed. The process is been thermodynamically verified and optimised. Since, the overall performance of this process does not only depend on the design of the process cycle and operating conditions but also on the chosen adsorbent material, further optimisation of the adsorptive and physical properties of the solid adsorbent is investigated. Thus, the optimal parameters of the potentially used porous materials is identified. Continuing the research on different adsorbent materials, an experimental investigation on the equilibrium properties of two competitive adsorbents is also performed. Besides the thermodynamic analysis, a dynamic model is presented for the investigation of the mass and heat transfer and its influence on the adsorption rate and consequently on the overall process performance. Since the initial stream is very dilute, it is expected that the adsorption rate will be low compared to other temperature swing processes and the capture rate will be affected by the heat transfer. Finally, the design and development of an experimental laboratory-scale apparatus is presented and analysed. Future design improvements are also discussed.

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Löf, Ludwig. "Evaluation of Dissolved Air Flotation for Water Purification: With Focus on Floc Characteristics and PFAS." Thesis, KTH, Kemiteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298378.

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I detta projekt har experiment utförts med mål att förse kommunalförbundet Norrvatten med data som kan användas som underlag för beslutsfattande angående om deras fällningslinjer i vattenreningsprocessen ska köras i flotation eller sedimentering. För detta ändamål har koncentrationen av poly- och perfluorerade alkylsubstanser (PFAS) samt karaktär av agglomererade partiklar (flockar) undersökts och jämförts mellan fällningslinjer som körs i olika konfigurationer. För flockkaraktär har skapandet och stabiliteten av flockar varit av intresse, eftersom flotation har ett mer turbulent flöde där flockarna riskerar att brista. Partikelstorlek, storleksfördelning och zeta potential identifierades som egenskaper som reflekterar flockarnas karaktär, dessa analyserades i en zetasizer. Koncentrationen av elva vanligt förekommande PFAS ämnen analyserades i projektet. Resultatet av flockkaraktär tyder på att det ej fanns någon större skillnad i skapandet av flockar samt deras stabilitet mellan de olika fällningslinjerna som undersökts. Detta eftersom zeta potentialen var identisk (-6.45 mV) för de analyserade proverna från respektive process. Analyserna och provberedningen bedömdes ha en hög mätosäkerhet, och några förbättringar som föreslås för att öka säkerheten är genomförande av komplementerande fotoanalys för att bekräfta likheter i utseende mellan flockar, samt att genomföra mer analyser så att en statistisk giltighet av analysen kan kvantifieras. För PFAS koncentrationen så var koncentrationen av PFAS lägre i utgående vatten från fällningslinje som körs i sedimentation (7.5 ng/l), jämfört med prov från linje som körs i flotation (9.2 ng/l). För fällningslinjen som kördes i flotation så skapades skum med höga koncentrationer av PFAS (3800 ng/l) jämfört med analyserade vattenprover (5.5–9.2 ng/l), detta identifierades som en potentiell källa för PFAS-avlägsning. Resultaten av PFAS baserades endast på en provtagningsserie, och förbättringar av validitet kan åstadkommas genom samling av mer analysdata för samma processer, och genom att analysera ett av proverna i två olika instrument, som båda analyserar PFAS koncentration.
In this project, attempts have been made to collect data that allows the municipal association Norrvatten in the decision-making process on the flotation/ sedimentation step of their water treatment process. In this sense, poly- and perfluorinated alkyl substances (PFAS) concentration and the characteristics of agglomerated particles (flocs) have been investigated and compared between the two modes that the process can be operated. For the floc characteristics, the creation and stability of the flocs were investigated, and the particle size, size distribution and zeta potential was identified as important properties and thereafter analysed using the instrument zetasizer. The concentration of eleven different PFAS compounds were analysed. The results of floc characteristics show that there is no major difference in creation and breakage of flocs in the two investigated modes, since the analysed samples had the same zeta potential, -6.45 mV. The results were deemed uncertain because of varying results, and improvement suggestions include using photoanalysis to confirm similar floc appearances and to produce more data so a statistical validity can be quantified. As for the PFAS concentration, the concentration of PFAS were slightly lower in the treatment step in which sedimentation was utilized (7.5 ng/l) compared to when flotation was utilized (9.2 ng/l). The flotation mode did, however, create foam with a high PFAS concentration (3800 ng/l) compared to the liquid samples (5.5-9.2 ng/l), so a potential PFAS removal source was identified. The results were based on one sample series, so improvements of validity can be achieved by gathering more data, analysing more samples, and analysing the same sample in two different instruments measuring PFAS concentrations.

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Ljung, Sebastian. "CFD simulation of particle matter inside an automotive car and the purification efficiency of cabin air purifier." Thesis, KTH, Hållbara byggnader, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-257682.

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The purpose of this thesis work was to study the airflow patterns and the particle distribution in a generic car cabin in order to evaluate the air quality and find how it can be improved. A 3D CAD model was created using the Solidworks software program and meshed using ICEM CFD software. The ICEM CFD software was used to generate the mesh and ANSYS FLUENT was adapted for the simulation. In total, 12 different cases were simulated by considering different inlet velocities and vent setup. The predicted results were further used to analyze the airflow and particle distribution in the entire car cabin. With higher inlet velocity there were more particles being transported to the rear part of the cabin. In general, the particle concentration was higher in the front of the cabin when they were introduced through the inlets, especially with low inlet velocities. Opening the recirculation vents resulted in a slight reduction of the flow to the rear side and reduced the particle distribution accordingly. When smoke particles were introduced in the rear seats, they mostly stayed in the rear of the cabin, especially with low inlet flow velocities as the air did not mix sufficiently. Overall a higher inlet airflow velocity reduced the number of particles that were trapped on the front and rear seats. However, an increase in the number of particles that were trapped on the ceiling, floor and walls were obtained.
Syftet med den här avhandlingen var att studera luftflödesmönster och partikelfördelningen i en generell bilkabin för att utvärdera luftkvaliteten och se hur man kan förbättra den. En 3D CAD-modell skapades med hjälp av Solidworks och ett rutnät skapades med hjälp av ICEM CFD. ICEM CFD användes för att generera rutnätet och ANSYS FLUENT användes för simuleringarna. Totalt simulerades 12 olika fall bestående av olika inflödeshastigheter och ventilinställningar. De beräknade resultaten användes sedan för att analysera luftflödet och partikelfördelningen i hela bilkabinen. Med högre inloppsflöde var det fler partiklar som transporterades till bakre delen av bilkabinen. Överlag var partikelkoncentrationen högre i framdelen av kabinen när partiklarna introducerades i inloppsventilerna, särskilt vid låga inloppshastigheter. Att öppna recirkulationsventilerna resulterade i en liten minskning av luftflödet till bakdelen av kabinen och även så partikelfördelningen. När rökpartiklar introducerades i baksätena, stannade de för det mesta i bakdelen av kabinen, särskilt vid låga inloppsflödeshastigheter då luften inte blandades tillräckligt. Överlag innebar en högre inloppsflödeshastighet reducerade mängden av partiklar som fastnade på fram- och baksätena, men ökade mängden partiklar som fastnade på taket, golvet och på väggarna.

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Dlangamandla, Cynthia. "Bioflocculant dissolved air flotation system for the reduction of suspended solids-lipids-Proteinaceous matter from poultry slaughterhouse wastewater." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2485.

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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016.
Poultry slaughterhouse wastewater (PSW) contains organic matter that can be degraded by microorganisms. Such matter can further be used by the microbial community as a nutrient source for growth. Moreover, this type of wastewater also contains a high quantity of particulate matter, lipids and proteins, including antimicrobial compounds such as triclosan (TCS) and trichlorocarbanilide (TCC) used during cleaning and sanitising of processing facilities. Lipids and particulate matter lead to clogging of pipes and fouling of diffusers in the wastewater treatment plants (WWTPs). To overcome this problem, a pre-treatment system such as a dissolved air flotation system (DAFs) in which synthetic flocculants are used, is commonly used prior to the biological treatment of the wastewater. Synthetic flocculants add to the environmental burden associated with the use of synthetic compounds, particularly when these compounds are used in WWTPs. This study focused on the reduction of suspended solids, lipids and proteinaceous matter using a bioflocculant- supported DAF for the treatment of PSW.

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20

Yang, Linda, and Robert Liao. "Water Purification : Research on the Energy Supply of Air Gap Membrane Distillation for Access to Clean Water." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-282905.

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Water stress is an ongoing problem in many places in the world, while the demand for clean and safe freshwater is growing due to the increasing population. In many developing countries, water supplies often are contaminated with arsenic, fluoride, etc. Therefore, it is important to realize that water scarcity and contamination issues concern only one sector but many. HVR Water Purification AB is developing a water purification prototype – ELIXIR 500 - using the air gap membrane technology and is implemented in Odisha, India, aiming to supply with 200 litre water daily. This thesis aims to estimate future energy sources to supply this prototype and explore the possibilities of using only renewable energy resources from technical, economic, and environmental perspectives. These are achieved by firstly identifying the energy possibilities in Odisha, India, and then calculating the feasibility of each solution chosen and finally analyzing the results. Among the energy sources, which are power grid, wind and solar power, diesel generator and solar-diesel hybrid system. It is found that the energy source to the prototype supplied by the power grid is 0.057 USD per litre water, which is the cheapest option. However, it is not feasible due to the lack of electrification from the local network. Meanwhile, the solar-diesel hybridized energy system is the most economical option if renewable energy sources are integrated with 0.11 USD per litre water.
Vattenstress ett pågående problem på många ställen i världen medan efterfrågan på rent och säkert dricksvatten växer på grund av den ökande befolkningen. I många utvecklingsländer är vattenförsörjningen ofta förorenade med arsenik, fluor osv. Det är därför viktigt att inse att vattenbrist och föroreningar inte bara rör en sektor utan många. HVR Water Purification AB utvecklade en prototyp för vattenrening - ELIXIR 500 - med hjälp av luftspaltmembrantekniken (eng: air gap membrane distillation och implementeras redan i Odisha, Indien, med målet att förse 200 liter rent vatten dagligt. Denna avhandling syftar till att uppskatta de framtida energikällorna för att tillhandahålla denna prototyp och utforska möjligheterna att endast använda förnybara energikällor ur tekniska, ekonomiska och miljömässiga perspektiv. Dessa uppnås genom att först identifiera de olika energimöjligheter i Odisha, Indien, följt av beräkningar om utförbarhet för varje vald lösning och slutligen en analys av resultaten. Bland energikällorna elnät, vind, sol, diesel generator och sol-diesel hybrid system har visat sig att energikällan till prototypen som levereras av elnätet som kostar 0.057 USD per liter vatten som det billigaste alternativet, men det är inte möjligt på grund av bristen på elektrifiering från det lokala elnätet. Å andra sidan är det hybridiserade energiskombinationen med solkrafts och diesel det billigaste alternativet om förnybara energikällor ska integreras, resultatet visade att vara 0.11 USD per liter vatten.

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21

Delduque, Thalita Pereira. "Remoção da amônia por air stripping em canais corrugados helicoidais." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2261.

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CNPQ
O presente trabalho propõe verificar o desempenho de um canal corrugado helicoidal aplicado na remoção de amônia, por meio do processo air stripping. O sist p ssui iâ tr i t r 4’’(≈100 m) e 10m de comprimento disposto de forma helicoidal. Avaliou-se a influência das condições operacionais como: vazão de ar (1000 L min-1 a 3000 L min-1), vazão do líquido (0,2 L min-1 a 1,0 L min-1), concentração de nitrogênio, pH (9,0 a 12,0) e declividade do canal (5% a 20%) na remoção da amônia. Foram realizados ensaios de caracterização hidrodinâmica do sistema com ajuste dos modelos uni-paramétricos: de N-reatores de mistura completa em série, dispersão de grande intensidade e pequena intensidade, visando a determinação dos coeficientes globais de transferência de massa (KLa). Entre os principais resultados, a massa de alcalinizante necessária para elevar o pH em média de 5 para 11,5, foi de 2,875g de NaOH por g de N presente na água residuária. Posteriormente, ensaios hidrodinâmicos indicaram que o escoamento do sistema tende a ser pistonado em função do seu alto número de reatores de mistura completa em série (49 a 69). Foram realizados 30 ensaios utilizando o planejamento estatístico, Delineamento Composto Central Rotacional (DCCR) com coeficiente de transferência de massa (KLa) de 19,7h-1 nas condições otimizadas de pH 10,5, Qar=2000 L min-1, Qliq=0,2 L min-1 na concentração de 0,6 mgL-1 N-NH3 atingindo a eficiência de remoção de N-NH3 de 70%. Com os valores experimentais foi possível obter o modelo reparametrizado das variáveis codificadas, que representa a remoção de N-NH3(%) em função do pH, da vazão de ar, da vazão do líquido e da concentração de N-NH3. Ao se comparar com torres convencionais de air stripping, o canal corrugado proporcionou maior tempo de contato ar com o líquido, para injeção do ar e menor altura manométrica de elevação da água residuária, reduzindo gastos construtivos e com energia elétrica.
The present work intent to verify the performance of a helical corrugated channel applied in the ammonia removal, through the air stripping process.The syst h s i t r l i t r 4 "(≈100 mm) and 10m long, helically arranged. The influence of the operating conditions was evaluated as: air flow (1000 Lmin-1 at 3000 L min-1), liquid flow (0.2 L min-1 at 1.0 L min-1), nitrogen concentration, pH (9.0 to 12.0) and channel slope (5% to 20%) in the ammonia removal. It was performed hydrodynamic characterization of the system with adjustment of the uni-parametric models: complete mix N-reactors in series, big intensity and small intensity dispersal, aiming the determination of the global coefficients of mass transfer (KLa). Among the main results, the alkaline mass required to raise the pH from 5 to 11.5 on average was 2.875 g of NaOH per g of N present in the wastewater. Subsequently, hydrodynamic tests indicated that the drain of the system tends to be pistoned due to its high number of compete mix reactors in grade (49 to 69). A total of 30 experiments were performed using the statistic design, Design Central Composit Rotational (DCCR) with mass transfer coefficient (KLa) of 19.7h-1 under optimized conditions of pH 10.5, Qar=2000 L min-1, Qliq=0.2 L min-1 in the concentration of 0.6 mgL-1 N-NH3 achieving the efficiency of removal of N-NH3 of 70%. With the experimental values it was possible to obtain the reparametrized model of the coded variables, which represents the removal of N-NH3 (%) as a function of pH, air flow, liquid flow and N-NH3 concentration. When compared to conventional air stripping towers, the corrugated channel provided longer air-to-liquid contact time for air injection and lower manometric height of wastewater elevation, reducing constructive and electricity expenditures.

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22

Ben, Jaber Mouna. "Biofiltration d'H2S - Cas du traitement aérobie de l'air et de la purification anoxique de biogaz." Rennes, Ecole nationale supérieure de chimie, 2016. http://www.theses.fr/2016ENCR0036.

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23

Randall, Andrew A. "Operational and exocellular biopolymer characteristics of sludges generated from an air products and a convential activated sludge system." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/43890.

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This study compared the sludge characteristics of a lab-scale Air Products (A/O) and a conventional activated sludge system. The sludges were analyzed for operational properties and the exocellular biopolymers of each sludge was characterized. Operational analysis mainly consisted of measurements of settling (SVI) and dewatering (specific resistance, CST) parameters at each sludge age. Biopolymers were measured using pH extraction followed by gel filtration and subsequent analysis for carbohydrate and protein concentrations. The results showed a high degree of similarity between the two systems both operationally and with respect to biopolymer characteristics. The A/0 system did produce a lower effluent soluble COD at sludge ages below 5 days. Also, the A/O system showed some consistent differences in the distribution of bound and unbound fractions of protein and carbohydrate ECP but these had no discernibleÂ· effect on sludge operational characteristics. In addition relationships between unbound ECP and effluent BOD, bound HMW ECP and SVI, and phosphorus and Mg uptake were observed, with varying degrees of consistency, in this study.
Master of Science

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24

Staudinger, Jeff. "Evaluation of mass transfer correlations for packed column air stripping of volatile organic contaminants from water supplies." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/101153.

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The application of packed column air stripping systems to the removal of volatile organic contaminants (VOCs) from drinking water sources was investigated. The crucial element for the design of such systems exists in obtaining accurate predictions of mass transfer rates. The first phase of this study evaluated three semi-empirical correlations available for predicting packed column mass transfer rates. From this initial screening, the Onda model was selected for further investigation. A test data base was established from water treatment pilot study results reported in the literature. Ten separate studies were selected for evaluation, encompassing approximately 450 data points. Eleven different VOCs were encountered in these investigations, and the basic packing types tested included rings, saddles, Tri-Packs, and Tellerettes. Comparison of measured mass transfer rates with the corresponding rates predicted by the Onda correlation yielded a relative standard deviation of 17%. A ± 30% accuracy value was therefore assigned to the model based on 90% confidence limits. This assessment agrees with the observed accuracy of the correlation for the chemical engineering-based system results utilized in the model's original derivation. From the overall evaluation, no severe deficiencies and/or limitations with the Onda correlation were noted. In particular, gas-phase resistance predictions appeared reasonably accurate. However, further investigative studies involving observed column performance with larger packing materials (≥2 inches in nominal size) is encouraged to verify the accuracy of the correlation for such situations. Within the context of the evaluation procedure, several related areas were investigated. First, Henry's constant temperature relations reported in the literature were established within approximately 20% for common VOCs at low concentration levels. Secondly, the transfer unit performance model for calculating observed mass transfer rates was found sensitive to experimental measurement errors below a stripping factor of 1.5. Therefore, measured results obtained under such operating conditions must be viewed with appropriate caution. Finally, economic design boundaries for column operational parameters were established based upon optimization study results reported in the literature.
M.S.

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25

Kieffer, Daniel W. "Feasibility of recycling air conditioner condensate for use as process water for a manufacturing facility." Oklahoma City : [s.n.], 2008.

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26

Guz, Ricardo. "Associação de sistema biológico do tipo lodo ativado com reatores air lift e fotocatálise heterogênea com TiO2 para a remediação de efluente oriundo da produção industrial de TNT." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/1768.

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Na etapa de purificação do trinitrotolueno (TNT) produzido nas indústrias, são realizadas duas lavagens ao final do processo. A primeira lavagem é realizada com água vaporizada, na qual origina-se o primeiro efluente, denominado água amarela, em seguida, é realizada uma segunda lavagem com a utilização de sulfito de sódio (Na2SO3), gerando o segundo efluente água vermelha. O presente trabalho teve como objetivo estudar os efeitos individuais, bem como, a associação da fotocatálise heterogênea utilizando TiO2 e tratamento biológico em reator air lift utilizando lodo ativado (biomassa bacteriana), para a remediação de águas residuais contaminadas com compostos nitroaromáticos, a fim de reduzir a toxicidade e ajustar os parâmetros legais de acordo com órgãos regulamentadores para despejo em vias aquáticas. O tratamento fotocatalítico foi conduzido por meio de desenho fatorial obtendo as melhores condições reacionais (pH 6,5 e concentração de TiO2 0,1 gL-1), sendo os melhores resultados obtidos em 360 minutos de reação, reduzindo 97,00% da absorbância em 275 nm, 94,20% da demanda química de oxigênio (DQO), 67,70% de fenóis totais, bem como uma redução total dos picos constatados e atribuídos a compostos nitroaromáticos por cromatografia líquida de alta eficiência. No tratamento biológico, observou-se redução de 53,40% da absorbância em 275 nm, 10,00% de DQO e 36,00% de fenóis totais em períodos curtos (3 dias), já para períodos longos (48 dias), houve uma influência antagônica nos resultados de forma que ocorreu a elevação destes parâmetros (DQO e fenóis totais) ao invés de sua redução. A análise cromatográfica confirmou a eficiência da degradação biológica por meio da redução de picos correspondentes a compostos como DNT e TNT. A associação dos tratamentos fotocatalítico e biológico apresentou resultados de redução da ordem de 91,10% de absorbância, 70,26% de fenóis totais e 88,87% de DQO. Enquanto que, a associação dos tratamentos biológico e fotocatalítico gerou eficiências relativamente inferiores, apresentando redução de absorbância de 77,30%, 62,10% de redução dos fenóis totais e uma diminuição de 87,00% da DQO. De maneira geral, ao compararmos os processos químico e biológico de forma isolada, o tratamento fotocatalítico apresentou os melhores resultados. Porém, comparando os resultados de forma isolada e as associações estabelecidas, a associação biológico x fotocatalise apresentou resultados mais promissores para o tratamento do efluente água vermelha.
Trinitrotoluene in the purification step (TNT) produced in industries, are carried out two washes at the end of the process. The first wash is done with vaporized water, which originates from the first effluent called yellow water, then the second washing with the use of sodium sulfite is performed (Na2SO3), generating a second effluent red water. This study aimed to study the individual effects, as well as the association of heterogeneous photocatalysis using TiO2 and biological treatment in air lift reactor using activated sludge (bacterial biomass) for the remediation of wastewater contaminated with nitroaromatic compounds in order to reduce toxicity and adjust the legal parameters according to regulatory agencies for disposal in waterways. The photocatalytic treatment was conducted by factorial design obtaining the best reaction conditions (pH 6.5 and concentration of TiO2 0.1 gL-1), with best results obtained at 360 minutes of reaction, reducing the absorbance 97.00%, 94.20% of the chemical oxygen demand (COD), 67.70% of total phenols, as well as a total reduction of observed peaks and assigned to nitroaromatic compounds by high-performance liquid chromatography. In the biological treatment, there was a 53.40% reduction in absorbance at 275 nm 10.00% 36.00% COD and total phenols in a short time (3 days), while for extended periods (48 days) there was an antagonistic influence on the results so that was the elevation of these parameters (COD and total phenols) instead of reducing. Chromatographic analysis confirmed the effectiveness of the biological degradation by reducing the peaks corresponding to compounds DNT and TNT. The Association of photocatalytic and biological treatments decreased results in the order of 91.10% absorbance, 70.26% of total phenols and 88.87% of COD. While the combination of biological and photocatalytic treatments generated relatively lower efficiencies, with 77.30% of absorbance reduction, 62.10% reduction of total phenols and a decrease of 87.00% of COD. In general, when comparing the chemical and biological processes in isolation, the photocatalytic treatment showed the best results. However, comparing the results of isolation and established associations, the association biological x photocatalysis showed more promising results in the treatment of red water effluent.

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Khunsupat, Ratayakorn. "Poly(allylamine) and derivatives for co2 capture from flue gas or ultra dilute gas streams such as ambient air." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44909.

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Polymers rich in primary amine groups are proposed to be effective adsorbents for the reversible adsorption of CO2 from moderately dilute gas streams (10% CO2) and ultra-dilute gas streams (e.g. ambient air, 400 ppm CO2), with their performance under ultra-dilute conditions being competitive with or exceeding the state-of-the-art adsorbents based on supported poly(ethyleneimine) (PEI). The CO2 adsorption capacity (mmol CO2/g sorbent) and amine efficiency (mmol CO2/mmol amine) of linear poly(allylamine) (PAA), cross-linked poly(allylamine) prepared by post-polymerization crosslinking with epichlorohydrin (PAAEPI), and branched poly(allylamine) prepared by branching of poly(allylamine) with divinylbenzene (PAADVB) are presented here and compared with state-of-the-art adsorbents based on supported PEI, specifically branched and linear, low molecular weight PEI. Silica mesocellular foam, MCF, serves as the support material for impregnation of the amine polymers. In general, branched polymers are found to yield more effective adsorbents materials. Overall, the results of this work show that linear PAA, cross-linked PAAEPI, and branched PAADVB are promising candidates for solid adsorbents with high capacity for CO2.

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Alberte, Tania Maria. "Estudo do tratamento de aguas residuarias por lodo ativado em reator "air-lift" de tubos concentricos." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255471.

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Orientador : Ranulfo Monte Alegre
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-03T14:22:54Z (GMT). No. of bitstreams: 1 Alberte_TaniaMaria_D.pdf: 9835439 bytes, checksum: 74ab1a7efc7d568bc9c3b37f762f08ec (MD5) Previous issue date: 2003
Resumo: Reatores "air-lift" são uma classe especial de coluna de bolhas, sendo recentemente utilizados em processos químicos, bioquímicos e em tratamento de águas residuárias. Neste trabalho, estudou-se o desempenho de um reator "air-lift" de tubos concêntricos no tratamento de água residuária sintética utilizando Iodo ativado. O reator construido de aço-inox, com tubos de aeração e reciclo de 1,2 e 1,5 m respectivamente, foi alimentado com água residuária sintética, sendo o Iodo separado em sedimentador na parte superior do reator e reciclado ao mesmo. A pressão manométrica no reator variou de O a 1,2 Kgf.cm-2, vazão de ar de 200 a 1600 mL.min-1 e vazão de substrato de 200 a 400 mL.h-1. Para cada taxa de alimentação, vazão de ar e pressão, o reator foi operado de forma contínua até que o estado estacionário hidráulico e microbiológico fossem atingidos. As amostras foram retiradas na altura média do reator e análises da Demanda Química de Oxigênio (DQO) e biomassa (quantificada como sólidos suspensos voláteis - SSV) foram feitas de acordo com métodos descritos pelo "Standard Methods for the Examination of Water and Wastewater" (1985). Os três parâmetros, vazão de alimentação, vazão de ar e pressão, variaram gradativamente, além da concentração de DQO do substrato (1100 a 8600 mgDQO.L-1), de forma que foi possível aumentar a concentração de Iodo no reator (SSV) de 1010 a 15000 mgSSV.L-1, sendo este último valor cerca de cinco vezes maior que os de processos convencionais de Iodo ativado, que é de 2000 a 3000 mgSSV.L -1 (Ramalho, 1983). Isto permitiu aumentar a eficiência de redução de DQO de 47 a 87%, respectivamente para reator operado a pressão ambiente e com variação de pressão. O coeficiente de transferência de oxigênio (K1a) aumentou com o aumento da vazão de ar até o limite de 1000 mL.min-1 (5,41 h-1), decrescendo para vazões superiores a esta, possivelmente devido à coalescência de bolhas. O coeficiente de retenção de gás (Eg) foi determinado e, para as vazões de ar testadas (200 a 1400 mL.min-1), variou de 2,08.10-3 a 12,95.10-3, proporcionalmente às vazões de ar utilizadas
Abstract: Air lift reaetors are a speeial elass of bubble eolumns and are been reeently used in ehemieal and bioehemical processes, as well as in wastewater treatment. In this work, it was studied the performanee of aeoneentrie tube air lift reaetor in the synthetie wastewater treatment by aetivated sludge. The reaetor was eonstrueted of stainless steel, 1.2 m high of riser and 1.5 m high of downeomer. It was fed with synthetie wastewater and the sludge was separeted in a sedimentator in the top of reaetor and reeyeled. The manometrie pressure varied from O to 1.2 kgf.em'2, the air flow rate from 200 to 1,600 mL.min-1 and the feed solution from 200 to 400 mL.h -1. To eaeh feed solution of synthetie wastewater rate, air flow rate and pressure, the reaetor was operated in eontinuous form until the hidraulie and mierobiologieal steady-state was reaehed. The samples were eolleeted in the half of the reaetor. Chemieal oxygen demand (COO) and volatils solids eoneentration (VSS) was determinated aceording to ín Standard Methods for the Examínation of Water and Wastewater (1985). Feed solution rate, air flow rate and pressure rangedgradually, as well as eoneentration of feed synthetie wastewater (1,100 of 8,600 mgCOO.L-
Doutorado
Doutor em Engenharia de Alimentos

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29

Takwi, Colette Nchong. "An assessment of the management of odour at the Athlone wastewater treatment works, Cape Town." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2788.

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Thesis (MTech (Environmental Management))--Cape Peninsula University of Technology, 2017.
¹Odour nuisance is increasingly becoming one of the major environmental problems in various countries across the world, especially odour associated with wastewater (Alfonsin et al., 2015; Schlegelmilch et al., 2005; Gostelow et al., 2001). As a result, the management of odour from Wastewater Treatment Works (WWTW) has become one of the environmental challenges besetting these facilities in recent times. The dispersion of odour across the physical boundary of wastewater treatment facilities presents not only negative environmental impacts to the natural environment, but also constitute a nuisance to surrounding populations. The Athlone (WWTW) located in the urban City of Cape Town with high demographics and adjacent to sensitive communities is thus not immune to poor air quality associated with WWTW activities (Walton, 2005). The population growth due to rural-urban migration has further put severe pressure on the facility and thus worsening the odour problem in the area. As a result, complaints have been received by the City Council from the surrounding communities over the last 20 years. In response to these complaints, the management of the WWTW introduced an odour management system with a particular focus on the use of a biotrickling filter coupled with the use of odour masking sprays. This management intervention was adopted in order to control the odour emitted to the atmosphere from the facility (WWTW). While these measures are said to reduce the prevalence of odour to the surrounding environment, it was, however, not clear whether or not such management interventions have reduced odour emitted from the treatment plant. This research was premised on two postulations as an approach to analyse the effect of the odour management plan adopted by the Athlone WWTW’s management and these are: 1) the perceived experience of odour by the adjacent neighbouring communities and, 2) the understanding of the inherent atmospheric dynamics (such as wind velocity, atmospheric stability, inversion layer and ventilation) which influence odour dispersal in the area. The research project argues that these two factors should be taken into account to ensure that the management of odour is sustainable. It is within this background that the research aimed at assessing the management of odour at the Athlone WWTW and to find out, if at all, the inherent local atmospheric conditions in the area and views of the surrounding communities are incorporated into the management of odour from the plant. The methodological design adopted in the study was case study approach. However, the atmospheric data (wind speed and direction) was obtained from the South African Weather Service (SAWS). These variables were analysed qualitatively and experimentally by the use of wind diagrams to provide insight on 2atmospheric stability conditions, surface inversion and topographical properties, and how these phenomenon influences odour dispersion. The study also reviewed previous odour management reports produced by the Althone WWTW management. This type of data was finally supported by data collected from the community by means of a community survey, face-to-face in-depth interviews and qualitative observation. Some major findings from the study revealed that the local weather of Athlone influences the dispersion of odour – facilitating dispersion in the summer through high wind velocities, while impeding dispersion during winter due to the presence of atmospheric stability conditions. Prevailing odours in this community has led to a general feeling of displeasure amongst community members especially since the management of the treatment plan does not include the local community in the decision-making process. In spite of these, the facility’s management approach was found to be more of a response driven nature even though it is ranked as a high-risk facility.

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Mukandi, Melody. "Modelling of a bioflocculant supported dissolved air flotation system for fats oil and grease laden wastewater pretreatment." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2637.

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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017.
In the recent past, the poultry industry in South Africa has grown due to an increased demand of poultry products as a result of population growth and improved living standards. Furthermore, this has led to poultry slaughterhouses generating high strength wastewater which is laden with a high concentration of organic and inorganic pollutants from the slaughtering process and sanitation of equipment and facilities. As a result, South Africa has promulgated restrictions and a set of quality standards for effluent discharged into the environment to minimize ecological degradation and human health impact. Hence, there is a need for improved Poultry Slaughterhouse Wastewater (PSW) pre-treatment prior to either discharge into municipal wastewater treatment plants (WWTP) or on-site secondary treatment processes such as anaerobic digesters. Additionally, amongst the pre-treatment methods for Fats, Oil and Grease (FOG) laden wastewater, flotation remains the most popular with Dissolved Air Flotation (DAF) system being the most applied. However, modelling and optimization of a biological DAF system has never been attempted before in particular for a bioflocculant supported DAF (BioDAF) for PSW pre-treatment. Process modelling and optimization involves process adjustment to optimize influential parameters. In this study, Response Surface Methodology (RSM) was used to develop an empirical model of a BioDAF for pre-treatment of PSW, for which a bioflocculant producer including production conditions, flocculant type and its floc formation mechanism, were identified. Twenty-one (n = 21) microbial strains were isolated from the PSW and their flocculation activity using kaolin clay suspension (4g/L) was quantified, with a mutated Escherichia coli (mE.coli) [accession number LT906474.1], having the highest flocculation activity even in limited nutrient conditions; hence, it was used for further analysis in other experiments. Furthermore, the optimum conditions for bioflocculant production achieved using RSM were pH of 6.5 and 36°C conditions which induced instantaneous bioflocculant production with the highest flocculation activity. The bioflocculant produced by the mE.coli showed the presence of carboxyl/amine, alkyne and hydroxyl functional groups, which was indicative that the bioflocculant contained both polysaccharides and some amino acids.

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Chevalier, Vincent. "Purification de l'air des cabines aéronautiques : Élaboration d'adsorbants innovants et compréhension de leurs comportements à des teneurs en composés organiques volatils sub-ppm." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI093.

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L’avion est un mode de transport en forte croissance qui n’échappe pas aux exigences d’un public de plus en plus sensibilisé à la pollution de l’air intérieur. De plus, l’arrivée de futurs réglementations limitants la concentration des COVs (Composés Organiques Volatils) dans les cabines aéronautiques nécessite de développer des solutions innovantes de traitement de l’air dont la compacité et la consommation énergétique soient compatibles avec les contraintes du secteur. Au vu de ces contraintes, l’adsorption est le procédé le plus approprié. Le charbon actif est le matériau le plus utilisé en tant qu'adsorbant en dépit de certaines limitations, notamment vis-à-vis de sa sélectivité et de sa régénération.L’objectif de cette thèse est d’améliorer la compréhension des phénomènes d’adsorption des polluants faiblement concentrés et d’étudier des matériaux alternatifs au charbon actif via l’élaboration et la fonctionnalisation d’adsorbants. Cinq matériaux (charbon actif, zéolithe, silice mésoporeuse et Metal-Organic Frameworks) possédant des propriétés chimiques (polarité, présence de cations, etc) et physiques (surface spécifique, taille des pores, etc) variées ont été testés sur un banc fabriqué dans le cadre de cette thèse dans des conditions de concentration sub-ppm. Les interactions (adsorption/désorption) entre ces matériaux et cinq polluants chimiques représentatifs des grandes familles de polluants de la qualité de l’air intérieur ont été étudiées dans des conditions variées (mélange mono-polluant, multi-polluant, humidité, etc). Enfin, une attention plus particulière a été apportée à l’adsorption de l’acétaldéhyde qui est très peu capté par les adsorbants usuels, au travers de l’élaboration de silices mésoporeuses et de zéolithes fonctionnalisées pour réagir spécifiquement avec ce polluant
Aircraft is a means transport in strong growth which does not escape the requirements of a public more and more sensitized with indoor air quality. In addition, the arrival of future regulations limiting the concentration of VOCs (Volatile Organic Compounds) in aircraft cabins requires the development of innovative air treatment solutions the compactness and energy consumption are compatible with the constraints of the sector. In view of these constraints, adsorption is the most appropriate method. Activated carbon is the most used material as an absorbent despite some limitations, especially with regard to its selectivity and regeneration.The aim of this work is to improve the understanding of adsorption phenomena at low concentration pollutants and to study alternative materials to activated carbon via the development and functionalization of adsorbents. Five materials (activated carbon, zeolite, mesoporous silica and Metal-Organic Frameworks) with varied chemical properties (polarity, presence of cations, etc.) and physical properties (specific surface area, pore size, etc.) were tested on a bench made during the present work under sub-ppm concentration conditions. The interactions (adsorption / desorption) between these materials and five chemical pollutants representative of the major families of indoor air quality pollutants have been studied under various conditions (mono-pollutant mixture, multi-pollutant, moisture, etc.). Finally, particular attention has been given to the adsorption of acetaldehyde, which is very poorly adsorbed by the usual adsorbents, through the synthesis of mesoporous silicas and functionalized zeolites to react specifically with this pollutant

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Queiroz, Lorena Aires Lombardi. "Desenvolvimento de um sistema de purificação de água com bomba de calor." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255771.

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Orientador: Vivaldo Silveira Júnior
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-18T01:57:04Z (GMT). No. of bitstreams: 1 Queiroz_LorenaAiresLombardi_M.pdf: 3856550 bytes, checksum: 772ac0e513c805ef7e7a144496ffab9a (MD5) Previous issue date: 2011
Resumo: O processo mais simples para que a água alcance pureza adequada é a destilação convencional, porém este método tem como inconvenientes seu alto gasto com energia elétrica e seu elevado consumo de água. Buscando alternativas para produzir água purificada com economia de energia elétrica e água de resfriamento, mas com produção quanto à pureza equivalente ao convencional, surge a possibilidade da elaboração de um sistema de purificação de água pela desumidificação do ar com o auxílio de uma bomba de calor. O equipamento projetado para a purificação de água opera segundo um ciclo termodinâmico de refrigeração e é composto por duas partes: uma bomba de calor por compressão de vapor, do tipo ar-ar acoplada em um duto de ar, e uma câmara, onde ocorre a umidificação do ar, com ar recirculado. Foram testados, ainda, dois tipos de umidificadores, com recheio de vidro e um nebulizador A água produzida pode ser considerada purificada já que apresentou valores de condutividade elétrica entre 4 e 5 µS/cm. A bomba de calor apresentou um melhor desempenho quando foi utilizado o nebulizador, já que os COP obtidos foram maiores do que os obtidos nos ensaios com recheio de vidro, referente à umidificação adiabática
Abstract: The simplest process for water to reach adequate purity is the conventional distillation, however this method has drawbacks such as their high expense with electric energy and their high water consumption. Searching alternatives to produce purified water with saving energy and water cooling, but with production as purity as conventional, there is the possibility of developing a system for purifying water by dehumidification the air with a heat pump. The equipment designed for water purification operates on a thermodynamic cycle of cooling and is composed of two parts: a heat pump vapor compression, the type air-air coupled into an air duct, and a chamber where it occurs humidifying the air, with recirculated air. Were tested also two types of humidifiers, with filling of glass and a sprayer. The water produced can be considered as purified, since it showed electrical conductivity values between 4 and 5 ms / cm. The heat pump showed a better performance when the spray was used, since the COP obtained were higher than those obtained in tests with a filling of glass on the adiabatic humidification
Mestrado
Engenharia de Alimentos
Mestre em Engenharia de Alimentos

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33

Magalhães, Aléx Fabiano Ribeiro de. "Proposição, implantação, partida e ajustes de reatores biologicos e fisico-quimicos para tratamento e reciclagem de efluentes de lavadores de veiculos em escala real." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258217.

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Orientador: Carlos Gomes da Nave Mendes
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
Made available in DSpace on 2018-08-04T11:01:23Z (GMT). No. of bitstreams: 1 Magalhaes_AlexFabianoRibeirode_M.pdf: 2242026 bytes, checksum: b4ae2e107eb7317d892ade5a7815f862 (MD5) Previous issue date: 2005
Resumo:Com a intenção de preencher a lacuna decorrente de poucos estudos sobre o tratamento de efluentes da lavagem de veículos, na presente pesquisa, propõe-se um sistema de tratamento composto de biofiltros aerados submersos seguidos por flotação por ar dissolvido na remoção dos principais contaminantes contidos nos mesmos. Para isso, foi concebida, instalada e operada uma instalação protótipo em escala real, visando possibilitar a reutilização do efluente tratado. O sistema foi montado em uma transportadora e destinado ao tratamento dos efluentes de lavagens de caminhões tipo baú através de lavador tipo ¿rollover¿. Apesar de terem sido previstos três meses para a operação do sistema, vários problemas de origem operacional do próprio lavador de veículos impediram a realização dos testes de longa duração. Mesmo assim, o período de testes foi útil para estabelecer-se quais alterações físicas deveriam ser incorporadas à instalação proposta para a solução de diversos problemas específicos relativos à concepção original do sistema, subsidiando dados para a otimização de futuros sistemas a serem implantados em escala real. Concluiu-se que, após as modificações introduzidas, tais como a alteração de dispositivos de entrada e saída dos reatores, substituição de acessórios de controle de pressão e vazão, entre outros, a alternativa proposta para tratamento e reúso deste tipo de efluente é plenamente viável
Abstract: With the intention to contribute for aim of filling out the emptiness provoked by few studies on the treatment of carwash affluent, in this research, it intends to create a treatment system composed of aerated submerged biological filter (BAS) following for the dissolved air flotation (FAD) on the removal of the main pollutants present in this effluent type. For that, it was become designed, installed and operated an installation prototype in real scale, seeking the water recycling. The system was installed at cargo transport interprise and destined to the treatment of the carwash effluent type "rollover". In spite of it have been preview three months for the operation time of the system, several operational problems of the washer accomplish of the long time tests. Even so, the time of tests was useful to establish which physical alterations should be incorporate in the installation proposed for the solution of problems to the original conception of the system, subsidizing data for the otimization of the future systems to be implanted in real scale. This research was finish, after the modifications, such as the alteration of inlet and outlet devices of the reactors, pressure and flow control, among other, the proposal alternative for treatment and reuse of rollover type carwash effluent type is fully viable
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil

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Cioce, Christian R. "Computational Investigations of Potential Energy Function Development for Metal-Organic Framework Simulations, Metal Carbenes, and Chemical Warfare Agents." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5666.

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Metal-Organic Frameworks (MOFs) are three-dimensional porous nanomaterials with a variety of applications, including catalysis, gas storage and separation, and sustainable energy. Their potential as air filtration systems is of interest for designer carbon capture materials. The chemical constituents (i.e. organic ligands) can be functionalized to create rationally designed CO2 sequestration platforms, for example. Hardware and software alike at the bleeding edge of supercomputing are utilized for designing first principles-based molecular models for the simulation of gas sorption in these frameworks. The classical potentials developed herein are named PHAST -- Potentials with High Accuracy, Speed, and Transferability, and thus are designed via a "bottom-up" approach. Specifically, models for N2 and CH4 are constructed and presented. Extensive verification and validation leads to insights and range of applicability. Through this experience, the PHAST models are improved upon further to be more applicable in heterogeneous environments. Given this, the models are applied to reproducing high level ab initio energies for gas sorption trajectories of helium atoms in a variety of rare-gas clusters, the geometries of which being representative of sorption-like environments commonly encountered in a porous nanomaterial. This work seeks to push forward the state of classical and first principles materials modeling. Additionally, the characterization of a new type of tunable radical metal--carbene is presented. Here, a cobalt(II)--porphyrin complex, [Co(Por)], was investigated to understand its role as an effective catalyst in stereoselective cyclopropanation of a diazoacetate reagent. Density functional theory along with natural bond order analysis and charge decomposition analysis gave insight into the electronics of the catalytic intermediate. The bonding pattern unveiled a new class of radical metal--carbene complex, with a doublet cobalt into which a triplet carbene sigma donates, and subsequent back-bonding occurs into a pi* antibonding orbital. This is a different type of interaction not seen in the three existing classes of metal-carbene complexes, namely Fischer, Schrock, and Grubbs. Finally, the virtual engineering of enhanced chemical warfare agent (CWA) detection systems is discussed. As part of a U.S. Department of Defense supported research project, in silico chemical modifications to a previously synthesized zinc-porphyrin, ZnCS1, were made to attempt to achieve preferential binding of the nerve agent sarin versus its simulant, DIMP (diisopropyl methylphosphonate). Upon modification, a combination of steric effects and induced hydrogen bonding allowed for the selective binding of sarin. The success of this work demonstrates the role that high performance computing can play in national security research, without the associated costs and high security required for experimentation.

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Daniel-David, Delphine. "Etude du mécanisme de désémulsification des émulsions de type eau dans pétrole brut par des polymers siliconés." Compiègne, 2006. http://www.theses.fr/2006COMP1636.

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Des émulsions stables de type eau dans huile se forment lors de la production de pétrole brut. Les asphaltènes du pétrole créent un film viscoélastique empêchant les gouttelettes d'eau de coalescer. La séparation de l'eau par l'ajout de tensioactifs est indispensable avant l'étape du raffinage. Notre étude a consisté à comprendre l'action de copolymères siliconés efficaces. Le copolymère choisi a d'abord été caractérisé à l'interface eau/air afin de cerner son comportement en l'absence des molécules du pétrole. Ensuite, afin d'élucider le mécanisme de désémulsification, plusieurs techniques ont permis d'étudier les interactions entre les asphaltènes et le copolymère. Le mécanisme retenu est le suivant: le copolymère s'adsorbe à l'interface eau/pétrole pour laquelle il a beaucoup d'affinité en se logeant dans les imperfections du réseau asphalténique. Il repousse ensuite les asphaltènes affaiblissant ainsi le film interfacial et provoque la coalescence des gouttelettes d'eau
Viscoelastic films of aggregated asphaltenes prevent the coalescence of water droplets in water -in-oil emulsions formed during crude oil exploitation. Demulsifying surfactants are used to promote phase separation before oil refining process. The aim of this PhD thesis is to explain a destabilization mechanism for a silicone polyether copolymer, by relating its structure to its performance. The copolymer was first characterized at the air/water interface in order to understand its adsorption without the presence of the indigenous crude oil components. Various techniques have been used to elucidate the destabilisation mechanism by the copolymer. The proposed destabilisation mechanism is as follows : the copolymer first adsorbs at the crude oil water interface into packing defect sites due to its high affinity for the oil water interface. Then, the copolymer molecules disrupt the asphaltene network, allowing the coalescence of water droplets

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Serafin, Guillaume. "Stratégies optimales de maîtrise de la qualité de l’air dans les bureaux : évaluation du potentiel des matériaux adsorbants." Thesis, La Rochelle, 2020. http://www.theses.fr/2020LAROS001.

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Les nombreuses études menées en France et dans le reste du monde au cours des vingt dernières années ont permis d’inscrire la qualité de l’air intérieur comme une problématique environnementale à part entière. L’enjeu de cette thèse repose sur l’évaluation de la qualité de l’air dans les bâtiments de bureaux, de sa qualification par le choix d’indicateurs pertinents à la recherche de solutions d’amélioration. Elle comporte deux volets aux objectifs complémentaires. Le premier traite de la caractérisation fine du potentiel des matériaux adsorbants pour la maîtrise de la qualité de l’air, sur la base de 6 polluants de familles chimiques différentes. Différents protocoles expérimentaux sont mis en œuvre afin de caractériser les différents aspects de la performance de 6 matériaux du marché, à savoir l’influence de la concentration sur les flux adsorbés, leur capacité d’adsorption, l’irréversibilité des processus, et la réduction des émissions des matériaux sur lesquels ils sont disposés. L’abattement des concentrations en formaldéhyde que peuvent procurer les matériaux adsorbants est ensuite évalué par des simulations de la qualité de l’air dans un bureau représentatif, en couplant une modélisation zonale des transferts aérauliques et de polluants dans l’ambiance à une modélisation détaillée des transferts dans les matériaux constitutifs des parois. Les résultats obtenus permettent d’analyser l’influence du type et de la position des matériaux adsorbants dans la pièce (plafond ou mur) et de juger de l’intérêt de recourir à ces matériaux par référence à d’autres stratégies de contrôle de la qualité de l’air. Le second volet de la thèse élargit la discussion en abordant la définition des traceurs les plus pertinents de la qualité de l’air dans les bâtiments de bureaux, en termes de risques sanitaires encourus par leurs occupants. Une méthode originale de hiérarchisation sanitaire des polluants présents dans l’air de ce type de bâtiments est proposée. 307 substances ayant fait l’objet de mesures de concentrations dans le monde sont ainsi évaluées vis-à-vis de leurs effets à seuil, via le calcul d’un indice de risque (IR), et de leurs effets cancérigène, mutagène, reprotoxique ou perturbateur endocrinien (CMRPE), via une classification de danger. Parmi elles, 57 sont considérées comme prioritaires de par leur classification CMRPE et 11 de par leur IR. Le mode de représentation graphique des résultats permet une sélection ou une actualisation facile des données, pour une analyse sur un périmètre géographique ou une période de mesure donnée, ou un suivi dynamique de la hiérarchisation. 130 substances dont certaines choisies car ne disposant pas ou peu de données de concentration dans la littérature ont fait l’objet d’une campagne de mesure dans 30 immeubles de bureaux de Nouvelle-Aquitaine. Les résultats obtenus permettent de compléter et d’affiner la hiérarchisation
The numerous studies carried out in France and in the rest of the world over the past twenty years have led to consider indoor air quality as a full environmental issue. The challenge of this thesis is the characterization of air quality in office buildings, from its qualification by the selection of relevant indicators to the definition of improvement solutions. It has two components with complementary objectives.The first one deals with the ability of sorptive materials to control indoor air quality. 6 commercially-available products, including 3 paints and 3 gypsum-based materials, were assessed against 6 well-known pollutants. Various experiments were carried out to address the influence of concentration on adsorption rate, the adsorption capacity of the materials, the irreversibility of the adsorption processes, and the decrease in the emissions from the walls when they are coated with sorptive materials. The reduction in formaldehyde concentrations that sorptive materials can provide is then evaluated from simulations of the air quality in a representative office. The model associates a zonal modeling of heat, airflows and pollutant transports in the room volume, and a detailed modeling of pollutants transfers within buildings materials. The simulation results show the influence of the type and arrangement of sorptive materials in the room (ceiling / wall). They also provide relevant information to assess the air cleaning efficiency of these materials by reference to other technical solutions for controlling indoor air quality. The second part of the thesis widens the discussion by tackling the identification of the most relevant pollutants to consider for an objective assessment of indoor air quality in office buildings. 307 substances having concentration measurements have been evaluated with regard to their threshold effects, through the calculation of a risk index (IR), and their carcinogenic, mutagenic reprotoxic or endocrine disruptor (CMRPE) effects, through existing hazard classifications. Among them, 57 are considered as priority contaminants due to their CMRPE classification. 11 others have an IR greater than 1. The graphical representation of the method results allows easy selection and updating of the data, for a more targeted study or a dynamic monitoring of the ranking. 130 substances including some selected as having no or very few concentration data have been measured in 30 office buildings located in Nouvelle-Aquitaine, France. These measurements were used to complete and refine the ranking based on published data

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Benyamina, Djalila. "Amélioration du fonctionnement d'un système extensif de traitement d'eaux usées urbaines (lagune de Rethondes) par recirculation et aération modérée." Compiègne, 1996. http://www.theses.fr/1996COMP965S.

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Au cours des 15 dernières années, le traitement extensif des eaux usées a pris en France une place importante parmi les procédés de traitement des eaux usées urbaines. Il représente environ 20 % du parc des stations traitant ces eaux. L'épuration résulte essentiellement de l'action symbiotique de communautés bactériennes aérobies et algales. Ces dernières génèrent par photosynthèse l'oxygène dissous nécessaire à la dégradation de la matière organique par les bactéries aérobies. Cette matière est d'abord convertie en CO2 et ammonium puis en présence de la lumière solaire en algues. Ce procédé dépend fortement des conditions climatiques et des cycles nocturnes et diurnes et peut induire dans certaines régions des émissions d'odeurs désagréables. Afin de mieux comprendre et d'améliorer les rendements épuratoires d'un tel système ainsi que de réduire les problèmes d'odeurs, nous avons étudié, depuis novembre 1992, l'influence d'une recirculation de l'effluent et d'une aération modérée sur un système lagunaire de 8000 m2 localisé à Rethondes (800 équivalents habitants), département de l'Oise, au nord de la France. L'effluent est recirculé (durant une année), à un faible taux (0. 15) de la sortie de la station vers le bassin de tête. L'étude de l'influence de la recirculation sur les différents paramètres indicateurs de pollution montre une amélioration des rendements de : la DCO brute de 15. 4 %, de la DCO dissoute de 12 %, des MES de 37 %, des PO43- brutes de 24. 3 %, des PO43- dissous de 17. 8 % et de la flore totale de 8 %. De plus, la recirculation avait induit une amélioration du rendement des NH4+ dissous de 10 % et une augmentation de +100% d'oxygène dissous en sortie du bassin primaire. Une autre approche permettant d'améliorer le rendement épuratoire et de supprimer les odeurs consiste à combattre l'installation de l'anaérobiose dans les couches supérieures de l'eau. A cet effet, nous avons construit un aérateur de surface permettant d'oxygéner les eaux sans remettre en suspension les matières décantées. La concentration en oxygène dissous passe ainsi de 0,1 mg/l à 3,8 mg/l.

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38

Franz, Douglas M. "Simulation and Software Development to Understand Interactions of Guest Molecules inPorous Materials." Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7788.

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The effect of inclusion of explicit polarization is investigated through several theoret- ical studies of crystalline porous materials herein. In addition to the use of Monte Carlo simulation for such studies, a robust molecular dynamics software is presented which is suitable for analyzing time dependent properties of gases or other molecules in porous materials and other condensed phase systems. Metal-organic frameworks (MOFs) are the main focus of the work included here, a relatively young class of materials originally in- troduced in the early 1990s. These are usually three dimensional crystalline nanoporous materials that exhibit unique properties such as gas separation, storage and catalysis. They are synthesized by the combination of a metal ion e.g. Cu2+ with an organic linker e.g. benzene dicarboxylate. They are a very popular topic of scientific research due to the diversity in possible structures and manifold utility – finding applications in electron transfer, sensing, drug release etc. Industrially, MOFs like HKUST-1 and others are on the global market for use in gas storage and separation in fuel cell and raw materials processing. These materials are often ideal candidates for computer simulation owing to their crystalline nature – a very large atomic system (that is, moles of particles) can be under- stood by only evaluating one or a few unit cells of the MOF, usually less than 5,000 atoms, and macroscopic properties such as gas sorption capacity and diffusion coefficients can be calculated through extrapolation of atomistic interactions in a mathematically infinite lattice. The software developed by the space group as of 2005, Massively Parallel Monte Carlo (MPMC), allows for sophisticated calculation of repulsion dispersion, electrostatic and polarization energies. In this work, Monte Carlo Molecular Dynamics (MCMD) is in- troduced, which can hybridize both methods to explore the phase space of a system with ease and better efficiency, as well as explore the effects of MOF flexibility and dynamic properties which to-date are rarely studied. Studies involving primarily CO2, H2 and CH4 will be presented, but other gases investigated include C2 H2 , C2 H4 , C2 H6 , N2 , H2 O and others. Metal-organic materials with a wide variety of composition and structure will also be presented. Finally, features of the software MCMD will be presented for use by future studies.

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Forrest, Katherine A. "Understanding Gas Sorption Mechanisms in Metal–Organic Materials via Computational Experimentation." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7023.

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Metal–organic materials (MOMs), a type of porous crystalline structure composed of organic ligands jointed with metal ions, have captured the interest of scientists as potentially useful in gas sorption applications. Some of the most crucial avenues of investigation are in H2 storage (for use as a clean burning fuel source) and CO2 capture and sequestration (to remove the greenhouse gas from the environment). A major advantage of MOMs for such applications is their high variability in terms of physical dimensions and chemical moieties, based on composition and synthesis conditions, making them potentially customizable for specific application if necessary structural characteristics are known. Computational experimentation is an important avenue for determining such specifications as it allows examination of gas/MOM interaction at the molecular level. In this dissertation a number of MOM structure are computationally studied in order to elucidate gas sorption mechanisms. These systems were probed by classical simulation using grand canonical Monte Carlo with a carefully chosen set of intermolecular interaction parameters. While the focus of this work is specifically H2 and CO2 sorptive behavior, the insights gained from simulation extend beyond these specific applications. Addressed first are a series of MOMs with rht topology, which possesses asymmetric copper paddle-wheels and easily functionalized linkers. Beginning with a prototypical structure and then branching out into more chemically interesting variants revealed surprising gas sorption behavior about the metal paddle-wheels (with a definite preference for one copper over its counterpart). A synthetic strategy for controlling the preferred open-metal sorption site through the inclusion of electron rich functionality in the linker bodies, was also revealed. An additional MOM with similar composition components, exhibiting zyg topology, also showed this metal preference effect on the asymmetric paddle-wheels. A second class of MOMs, composed of square-pillared grids and known as the SIFSIX series (due to the inclusion of SiF62− as pillaring units) was also examined. These structures have been shown excellent results for CO2 sorption making the elucidation of the sorptive mechanisms of great interest. Six different structures were examined, probing the effects of linker length, metal selection, and interpenitration of unbonded scaffolds. The nature of the CO2-MOM sorption interactions were revealed through simulation and provided insights regarding the synergistic effect of pore dimensions and SiF62− functionality for specifying specific behavior (i.e. high selectivity vs. high uptake). A final MOM, composed of Y3+ ions and chemically complex linkers, was also examined. Disorder in the crystallographic data (e.g. single atoms with multiple positions) indicated the coexistance of notably different unit cells in the same system. Nevertheless, simulations revealed favored sorption sites in conjunction with results from physical experimentation.

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40

Vašalovská, Petra. "Modelový výzkum účinnosti separačních technologií úpravy vody." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225461.

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Goal of this research was to recognize dissolved air flotation efficiency by the help of turbidity and UV absorbance removal for different conditions. As different conditions are meant the efficiency for different baffle position, different detention time in separation zone and checking results with adding chemicals compared to results without adding chemicals.

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Hauck, Wilhelm. "Procédé d'adsorption sur charbon actif avec régénération thermique de la colonne par induction électromagnétique : application au traitement d'air chargé en composés organiques volatils." Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL011N.

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Cette étude concerne un procédé d'épuration d'air chargé en COV par adsorption sur charbon actif. Deux produits types ont été choisis : le toluène et le butanol. On présente d'abord la mise au point d'une installation expérimentale de mesure d'isothermes d'adsorption mono- et multiconstituant. Les résultats expérimentaux sont confrontés avec différents modèles d'adsorption. Dans une deuxième partie, on étudie le chauffage par induction d'un lit de charbon actif en vue de sa régénération. La solution analytique des équations de l'électromagnétisme (Maxwell) pour une géométrie cylindrique permet d'abord d'estimer le profil de puissance volumique dissipée dans le lit. On propose ensuite un modèle de transfert de chaleur, utilisant ce profil de puissance dissipée, ce qui permet de calculer le profil de température à partir des conditions opératoires du procédé et des propriétés physiques du charbon actif. Ce modèle conduit à un logiciel de simulation et permet d'explorer l'influence des différents paramètres opératoires sur les profils de température dans le lit de charbon actif et de discuter des conditions optimales pour ce mode de régénération. On observe un bon accord entre les profils de température mesurés et les résultats du modèle. Dans une troisième partie, on présente des expériences de désorption d'une colonne de charbon actif chargé en butanol ainsi que quelques simulations d'adsorption - désorption sur des colonnes de charbon actif.

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Grobbelaar, Loreen. "Treatment of biodiesel wastewater in a hybrid anaerobic baffled reactor microbial fuel cell (ABR-MFC) system." Thesis, Cape Peninsula University of Technology, 2019. http://hdl.handle.net/20.500.11838/2812.

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Thesis (Master of Engineering in Chemical Engineering)--Cape Peninsula University of Technology, 2019.
The biodiesel industry produces large volumes of biodiesel wastewater (BDWW) during the purification of crude biodiesel. This wastewater is characterised by high concentrations of chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solids (TSS), and fats, oils and greases (FOG) which in turn defines BDWW as a highly polluted effluent. The low nitrogen and phosphorous content of BDWW creates an unfavourable environment for the growth of microorganisms, thereby making it difficult to degrade naturally. Biodiesel companies discharge untreated non-compliant wastewater directly to the municipal sewer system. Treatment prior to discharge is a necessity since the disposal of untreated BDWW may raise serious environmental concerns (i.e. disturbance of biological ecosystems) resulting in penalties liable by non-compliant companies due to the implementation of the waste discharge charge system (WDCS) which is regulated by the industrial waste discharge standard limits in South Africa (SA). This study aimed to combine the advantages of the conventional anaerobic baffled reactor (ABR) system with microbial fuel cell (MFC) technology resulting in an innovative technology used to treat high strength industrial BDWW at ambient conditions. Many studies have reported effective treatment of BDWW, however to date literature implementing an ABR equipped with MFC technology has not been reported. The main objectives of the study were to determine which parameters do not meet the industrial wastewater discharge standard limits, whether pH and carbon:nitrogen:phosphorous (C:N:P) ratio adjustments will suffice prior to treatment with the ABR-MFC, the maximum power density (PD) as well as to determine the treatment efficiency of the ABR-MFC.

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Bartuma, Ninorta. "Optimizing purification of oligonucleotides with reversed phase trityl-on solid phase extraction." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-76844.

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Oligonucleotides are synthetic strings of DNA or RNA used mostly for biochemical analysis and diagnostics. For them to be useful in these fields, a purity over 90% is most often required. However, when synthesizing these sequences, many “failures” (shorter sequences) are made in the step-wise process. The synthesized oligonucleotides need to therefore be purified. This is most often done with gel electrophoresis or liquid chromatography. These methods are, on the other hand, very time-consuming and laborious. Solid phase extraction (SPE) is a much faster purification method if optimized and it can be done with the standard cartridges as well as 96-well plates, that allow many samples to efficiently be run at the same time. With reversed phase (RP) SPE, the dimethoxytrityl (DMT) group, that is attached to the target at the final synthesis step, can be used for stronger retention to the bed sorbent and leaving only the target at the final eluting stage. The impurities without a DMT-on group, that do not adsorb to the sorbent, are washed away in earlier steps. The purpose of this study is to optimize an SPE method for purification of oligonucleotides. Two different cartridges, Clarity QSP (Phenomenex) and Glen-Pak (Glen Research) were used. The purity analysis and oligonucleotide identification were done using anion exchange - high performance liquid chromatography (AIE-HPLC) and time-of-flight mass spectrometry (TOF MS). To conclude, Clarity QSP achieved, at the most, a purity of 68.8% with the recommended SPE steps by Phenomenex. Alterations in the extraction procedure resulted in similar purity or lower. Glen-Pak reached a peak purity of 78.8% when doing a double salt wash of 5% ACN in 2 M sodium chloride and another double wash after detritylation with 1% acetonitrile. This method has to be further optimized in order to reach a purity of at least 90% to be useful in industrial settings.

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Wolfe, Christopher L. "Biological and physical treatment of crab processing industry wastewaters." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-08042009-040526/.

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Rouveirolles, Pierre. "Etude de la cinetique en phase gazeuse de reactions du radical nh2 a haute temperature." Orléans, 1987. http://www.theses.fr/1987ORLE2019.

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Reactions du radical nh::(2) avec des alcanes, h::(2) et h::(2)o. Les reactions etudiees jouent un role important dans la modelisation des processus de combustion ou de post-combustion des hydrocarbure et dans la connaissance du mecanisme reactionnel gouvernant le traitement par injection d'ammoniac des oxydes d'azote contenus dans les gaz d'echappement des machines thermiques

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Marichal-Gallardo, Pável Alejandro Verfasser], and Udo [Gutachter] [Reichl. "Chromatographic purification of biological macromolecules by their capture on hydrophilic surfaces with the aid of non-ionic polymers / Pável Alejandro Marichal-Gallardo ; Gutachter: Udo Reichl." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2019. http://d-nb.info/1219965022/34.

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Marichal-Gallardo, Pável Alejandro [Verfasser], and Udo [Gutachter] Reichl. "Chromatographic purification of biological macromolecules by their capture on hydrophilic surfaces with the aid of non-ionic polymers / Pável Alejandro Marichal-Gallardo ; Gutachter: Udo Reichl." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2019. http://nbn-resolving.de/urn:nbn:de:gbv:ma9:1-1981185920-332329.

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48

Steinbach, Sandra. "Dissolution and precipitation of air in dissolved air flotation." Thesis, 2012. http://hdl.handle.net/10210/6178.

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D.Ing.
The use of dissolved air flotation (DAF) as a water clarification process has gained momentum over the past two decades. Despite its increased application there is a lack of information concerning the understanding of the underlying principles of the process. Plants are being designed based mainly on empirical guidelines, especially with respect to the bubble production system. Bubbles are generated in the DAF process when water, supersaturated with air under pressure, is released under atmospheric conditions. The efficiency of air dissolution and precipitation determines the quantity of air available for flotation and thus, to a large extent, the success of the whole DAF process. The first part of this thesis deals with a rational model for predicting the air transfer efficiency in packed saturators which are used in most modern DAF plants to dissolve air into water. The model assumes the Lewis-Whitman two-film theory for interfacial mass transfer and uses the Onda correlations to estimate the mass transfer coefficient. The model provides good insight into the effects of key design parameters on the air transfer efficiency. The experimental verification of the model required a method for predicting the saturator air composition and a technique to practically determine the air transfer efficiency in the packed bed of an operating saturator. Both methods are described in detail in this study. The verification of the mass transfer model showed a close agreement of experimental and theoretical results and the model thus provides a powerful tool for the design of packed saturators. The second part of the thesis deals with air precipitation and the quantity of air released after depressurization. Based on a literature review on this subject it was assumed that the air release is incomplete and that it would be a function of the operating conditions of the saturation system as well as of the design of the injection nozzle across which the pressure is released. Since the injection nozzles play an important role in the DAF process numerous experiments were carried out which measured the released air volume for different nozzle configurations and saturator pressures. The results of this study showed that the air release after depressurization is indeed incomplete and that it takes a long time for all the excess air to come out of solution. It was found that the efficiency with which the air was released is a function of the saturator pressure and the nozzle design. The experimental observations led to the formulation of a two-step air release model, which explains the precipitation process in terms of a slow and fast release step. The mathematical framework for quantification of the model is provided. Once the model is quantified it will be possible to compare the performance of different injection nozzles solely with regard to their design features and independent of any parameters influencing the air release downstream of the nozzle. This model may then help to further the understanding of the precipitation process and could lead to the development of some rational guidelines for nozzle design and prediction of nozzle performance.

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CHANG, CHENG-YAO, and 張丞瑤. "Discussion on Integrating Residential Air Purification Device." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/v7n4g3.

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Chen, Chun-Chi, and 陳狀琦. "Application of Nano Photocatalyst on the Air Purification." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/kvxwjh.

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碩士
國立臺灣科技大學
營建工程系
94
Nano Photocatalyst is well known as an air purification material, such as formaldehyde and ammonia. A powerful device composed by nano photocatalyst is designed in the research to purify the air. A series of experimental parameters are set up to investigate the function of the device which included contact surface area of nano photocatalyst, concentration of formaldehyde, power of light source, speed of air and media of nano photocatalyst. The followings are the short description of the result of this research: 1. The higher the contact area of the surface of nano photocatalyst the higher air purification; 2. The higher concentration of formaldehyde the higher air purification; 3. The higher the power of light the higher air purification. A pattern is successfully applied to apply the result of this research on the real commercial product. The pattern is a fan modified by the proposed device to gain a additional function of air purification.

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Dissertations / Theses on the topic 'Purification of Air'

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