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Muz, Melis. "Ozone Treatment Of Excess Biological Sludge And Xenobiotics Removal." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614310/index.pdf.
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novel ozone-assisted aerobic sludge digestion process to stabilize and decrease the amount of excess sludge produced during biological treatment is presented in this study.
Excess sludge production is a well known burden for the treatment plants both legally and financially. Moreover, with the arise in the knowledge in recalcitrant compounds it is understood that it can act as a significant secondary pollutant.
With the developed pulse ozonation method, waste activated sludge samples from Ankara Tatlar and other Wastewater Treatment Plants (WWTP) were ozonated for different periods in Erlenmeyer flasks once a day on each of four consecutive days. Flasks were continuously aerated between ozone applications on an orbital shaker. The MLVSS, MLSS, COD and OUR parameters were measured routinely during the course of four days of digestion in order to optimize the process. Also pH, CST(capillary suction time) and SVI (sludge volume index) were followed. As a result MLVSS reductions of up to 95% were achieved with an ozone dose of only 0.0056 kg O3/kg-initial MLSS, at the end of the fourth day.
In another experimental set, ozone dose was increased on the last day in order to destroy the selected endocrine disrupting compounds, namely diltiazem, carbamazepine, butyl benzyl phthalate and acetaminophen and two natural hormones estrone and progesterone, which accumulated onto the sludge. Over 99%
removal of these contaminants were achieved on the fourth day. The analyses were conducted by using LC(ESI) MS/MS after solid phase extraction (SPE).
By this process it became possible to save on contact time, as well as achieving a bio-solids digestion far exceeding the standard aerobic process at the expense of a minimum of ozone dose with the additional micropollutants removal. The developed process is deemed superior over side-stream ozonation of activated sludge in that it does not cause any reduction in active biomass amount that should be maintained in the aeration tank.
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Vercellotti, Joseph M. "Kinetics of iron removal using potassium permanganate and ozone." Ohio : Ohio University, 1988. http://www.ohiolink.edu/etd/view.cgi?ohiou1182873479.
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Rani, Rupam. "REMOVAL OF EMERGING CONTAMINANTS FROM AQUEOUS SOLUTION BY OZONE -BASED PROCESSES." Master's thesis, Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/214782.
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Civil EngineeringM.S.Env.E.
The presence of emerging contaminants (ECs) in water and wastewater systems has become a subject of significant concern worldwide. These emerging contaminants are complex organic molecules which potentially affect human health and environment. Conventional wastewater treatment plants are unable to completely remove these contaminants from water and therefore can discharge them into environment. The need to develop effective methods for ECs removal is essential. This study assess the potential of ozone based advanced oxidation processes (AOP) to oxidize number of emerging contaminants. Different combinations of ozone with hydrogen peroxide and sodium persulfate were tested. For this study 1-4, dioxane, perfluorinated compounds (PFCs), N,N-Diethyl-metatoluamide, and three pharmaceuticals sulfamethoxazole, trimethoprim and carbamazepine have been selected. The effect of different process parameters such as chemical dosages, ozone weight percent, ozone flow rates, etc. on destruction of ECs were examined. It was observed that 1, 4-dioxane were persistent to direct ozone reaction, however were easily oxidized by hydroxyl radical. However, ozonation was solely very effective (> 99 %) in removing pharmaceuticals such as sulfamethoxaole, trimethoprim and carbamazepine. It was not very efficient for the removal of perfluorinated compound and N,N-Diethylmeta-toluamide. The operational conditions were optimized for maximum removal of every compound and their influence on the degradation process is discussed.
Temple University--Theses
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Janna, Hussein. "Occurrence and removal of emerging contaminants in wastewaters." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6097.
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Over the past decade, the occurrence and removal of emerging contaminants in the environment has received much attention. Both natural and synthetic progestogens, which are hormones, and also benzotriazoles are two examples of such emerging contaminants. Sewage treatment works are recognised as one of the main routes of these compounds to the environment. Low concentrations (nanograms per litre) of biologically active chemicals may exhibit an impact on aquatic organisms and human health. This study was undertaken to determine the occurrence and removal of these two classes of chemicals at sewage treatment works, along with an evaluation of the performance of advanced treatment and also to investigate their fate in the aquatic environment. Therefore, field-based sampling campaigns were undertaken at a sewage treatment works, rivers and potable water to achieve these aims. Solid phase extraction and LC/MS/MS were used in order to analyse the samples from these different locations, along with catchment modelling and assessment of how the use of benzotriazoles may contribute to their presence in the environment. The results have demonstrated that progestogens and benzotriazoles are in the sewage system; the natural hormone (progesterone) was the most predominant compound entering the sewage treatment work (46.9 ng/l) among the progestogens while concentrations of the benzotriazoles were two orders of magnitude higher than the progestogens. The conventional sewage treatment works were, to some extent, able to remove these compounds from wastewaters. However, this may not be adequate to afford protection to the environment. The investigation of advanced treatments, ozone, granular activated carbon and chlorine dioxide, indicated no further significant removal of progestogens, probably as a result of concentrations being close to method detection limits. However, there were indications that benzotriazoles were removed. A degradation study demonstrated that the natural hormone (progesterone) was degraded rapidly while benzotriazoles were not degraded. Catchment modelling indicated that high (up to 2,000 ng/l) concentrations of benzotriazoles would be present in surface waters used for potable supply, and consequently benzotriazoles were found in the tap water with mean concentrations of 30.9 ng/l (benzotriazole) and 15.1 ng/l for tolyltriazole. It is therefore apparent that although conventional treatment may be seen as effective, achieving over 90% removal, this may not be good enough. However, before investing in tertiary treatment, a number of factors, such as the effectiveness at different sites, the presence of degradation products and costs, both financial and in relation to energy use, need to be considered.
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Chaudhuri, Mahua. "Removal of hydrogen sulfide from groundwater using ozone and iron oxide-coated sand /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1422983.
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Storlie, Leslee. "An Investigation into Bromate Formation in Ozone Disinfection Systems." Thesis, North Dakota State University, 2013. https://hdl.handle.net/10365/26896.
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Ozonation is used as an alternative disinfection process to chlorination but unfortunately has a potential of oxidizing bromide, a natural component of water sources, to bromate. Bromate is a possible carcinogen with a maximum contaminant level of 10 ppb. To understand bromate formation in full-scale systems, a comprehensive study was conducted at the Moorhead Water Treatment Plant (WTP). Bromide concentrations in source waters were monitored. Water samples from locations in the ozonation chambers were collected and analyzed for bromate and other parameters. Results showed that bromate formation was increased through increases in pH, bromide, and ozone dose during high temperatures and was decreased by increases in organics. The impact of the bromate influential parameters was minimized at low temperatures. To assist Moorhead WTP on developing bromate control strategies, a modeling approach was adopted to predict bromate formation at various operational conditions using temperature, pH, ozone dose, bromide, and TOC.MWH Global, AWWA Scholarship
American Water Works Association (AWWA), Minnesota and North Dakota sections
North Dakota Water Resources Research Institute
Department of Civil Engineering, North Dakota State University
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DeGenova, John. "Oxidation and Removal of Thin Organic Films From A Wafer Surface: Fundamentals of Ozonated Water Application and Water Recycle." Diss., The University of Arizona, 2001. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2001_386_sip1_w.pdf&type=application/pdf.
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Thesis (Ph. D. - Chemical and Environmental Engineering)--University of Arizona, 2001.We acknowledge that the writer has two page 7's in this resource. (List of figures). Includes bibliographical references (leaves 214-218).
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Gilardi, Lorenza. "Removal of hydrogen sulfide from an air stream using UV light." Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206747.
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Volatile sulfur compounds are cause of concern because, when present in high concentrations, they constitute a danger for health because of their strong toxicity. Furthermore, for low concentrations, they are often a cause of complaint, because of their low odor threshold. In this context, the purpose of this Thesis is to evaluate a new technology for the abatement of sulfur-based malodorous compounds. The investigated technology consists in the use of ozone generating low-pressure UV mercury lamps, operating at room temperature. Hydrogen sulfide is often found in industrial processes, (e.g. WWTPs (Wastewater Treatment Plants), leather production, sewage treatment, garbage disposal, etc). Moreover, it presents both a very high toxicity a low odor threshold. Thus, due to its high representativeness of the case, hydrogen sulfide was chosen as reference compound for the purposes of this project. In order to evaluate a wide range of cases, several experiments using different residence times, humidity contents and inlet concentrations of the pollutant were conducted. The obtained results show that this technology generally presents discrete conversion efficiencies, although not suffcient to be used as freestanding process. For this reason, a pretreatment is revealed to be necessary. The best conversion efficiency was obtained for low flow rates and high moisture content. At the end of the project, as side-study, a possible pretreatment using an adsorbent bed constituted by granular ferric oxide was evaluated.
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Wong, Kit Iong. "Chemical removal of dichloromethane (DCM) from contaminated water using advanced oxidation processes (AOPs) :Hydrogen Peroxide Ozone UV." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3868740.
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Larcher, Simone. "Biological removal of sulfamethoxazole and 17 α-ethinylestradiol and the impact of ozone on biodegradability, estrogenicity and toxicity." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104773.
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The potential development of antibacterial resistance and endocrine disruption has led to increased research investigating the removal of antibiotics like sulfamethoxazole (SMX) and estrogens like 17alpha-ethinylestradiol (EE2) during biological wastewater treatment (activated sludge). Lab-scale studies have been carried out by researchers using activated sludge samples and bacterial isolates to investigate the biodegradability of these pharmaceutical compounds with varying and sometimes contradictory results. Both SMX and EE2 can react quickly with ozone (O₃) thus the implementation of O₃ as a final disinfection step during wastewater (WW) treatment may also result in the removal and transformation of these pharmaceutical compounds. However, the identification and characteristics of the ozonation by-products formed as a result of this treatment has yet to be fully explored. Ozone has also been predicted to increase WW biodegradability, suggesting its potential as a pre-treatment to activated sludge. The work presented in this thesis proposes an innovative way to evaluate changes in biodegradability and investigate the potential impact of transformation products. The use of controlled mixtures of pure bacterial cultures to model the biodegradation of SMX and EE2 at lab-scale was studied. This approach ensures a consistent microbial population that can be precisely repeated throughout a set of experiments, allowing the direct comparison of results, which is not possible using activated sludge samples due to their variable composition. The results showed that specific individual bacteria (R. equi and R. rhodocrous) were capable of successfully degrading SMX and EE2, however when they were combined with other bacteria to form mixtures there were no additive or synergistic effects observed. Using the controlled bacterial mixtures to model the biodegradation of SMX and EE2 separately, we were able to investigate the effects of the addition of an excess carbon source as well as ozone pre-treatment on the biodegradability of these compounds. The results demonstrated that there were no overall trends of co-metabolism of either compound with the excess carbon source and that slight differences in the bacterial composition of the mixture used (±1 to 2 bacterial strains) can alter the degradation trends observed (i.e. rate of compound removal). In general, ozonation increased the biodegradation of SMX by the bacterial mixtures; however the removal of EE2 was decreased. This was explained by the formation of an ozonation by-product that was preferentially biodegraded over EE2. We also investigated the ozone by-products formed after the complete disappearance of EE2. Two of these by-products were identified as open phenolic ring structures, suggesting a decrease in estrogenic activity. Using the YES assay these by-products were determined to be significantly less estrogenic than EE2, however they were observed to be more toxic to male fetal rats (15.5. days post-conception) demonstrating a greater negative impact on testosterone secretion. This emphasizes that a better understanding of emerging treatments such as ozonation is necessary before applying them in water treatment since the by-products may exhibit a greater toxic effect than the untreated parent compound.Les risques associés au développement de bactéries résistantes aux antibiotiques et aux effets des perturbateurs endocriniens suscitent un intérêt grandissant envers l'étude de l'élimination des antibiotiques, tel que le sulfaméthoxazole (SMX), et les œstrogènes, tel que le 17alpha-éthinylestradiol (EE2), lors de traitement biologique des eaux usées (boues activées). Des chercheurs ayant utilisés des échantillons de boues activées et des isolats bactériens pour évaluer en laboratoire la biodégradabilité de ces composés pharmaceutiques ont obtenus des résultats variables, voire même contradictoires. Considérant que le SMX et le EE2 réagissent rapidement avec l'ozone (O₃), l'utilisation de l'O₃ comme étape de désinfection des eaux usées de traitement peut également entrainer l'élimination ou la transformation de ces composés pharmaceutiques. Toutefois, l'identification et la caractérisation des sous-produits d'ozonation reste à faire. L'ozone a également le potentiel d'augmenter la biodégradabilité des eaux usées, ce qui suggère son potentiel en tant que pré-traitement aux systèmes à boues activées. Le travail présenté dans cette thèse étudie l'impact potentiel des produits de transformation et propose une approche innovatrice permettant d'évaluer les changements de biodégradabilité du SMX et du EE2 basée sur l'utilisation de mélanges contrôlés de cultures bactériennes pures. Cette approche permet l'utilisation d'une population microbienne qui peut être précisément répétée tout au long d'un ensemble d'expériences, ce qui permet la comparaison directe des résultats. Cette reproductibilité n'est pas possible en utilisant des échantillons de boues activées en raison de leur composition microbiologique variable. Les résultats démontrent que certaines bactéries (R. equi et R. rhodocrous), utilisées individuellement, étaient capables de dégrader le SMX et le EE2. Parcontre, lorsque combinées avec d'autres bactéries, aucun effet additif ou synergique fut observé. En utilisant les cultures mixtes pour évaluer les changements de biodégradabilité du SMX et EE2, étudié séparément, nous avons pu étudier les effets de l'ajout d'une source de carbone en excès ainsi que l'effet d'une pré-ozonation. Les résultats n'ont démontré aucune tendance générale liée au co-métabolisme et indiquent que de légères différences dans la composition bactérienne (± 1 à 2 souches bactériennes) peuvent influencer la dégradation (comme le taux d'élimination des composés). En général, la pré-ozonation a augmenté la biodégradation du SMX mais a diminué celle du EE2. Cette diminution est expliquée par la formation d'un produit de transformation préférentiellement dégradé par les bactéries. Nous avons également étudié la nature et l'impact des produits d'ozonation du EE2. Deux de ces sous-produits ne possédent pas d'anneau phénolique, ce qui suggère une diminution de l'activité estrogénique. En utilisant le test YES ces sous-produits ont démontré une estrogénicité plus faible que celle du EE2. Toutefois, ceux-ci ont démontré une plus haute toxicité sur les testicules de fétus de rats (15.5 jours post-conception) mesurée par une diminution de la sécrétion de testostérone. Ces résultats soulignent l'importance de mieux comprendre le devenir des produits pharmaceutiques au cours de traitement des eaux puisque les produits de transformation peuvent présenter un plus grand effet toxique que les composés parents non traités.
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Oputu, Ogheneochuko Utieyin. "Advanced oxidation process using ozone/heterogeneous catalysis for the degradation of phenolic compounds (chlorophenols) in aqueous system." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2510.
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Thesis (DTech (Chemistry))--Cape Peninsula University of Technology, 2016.The use of ozone as an advanced oxidation process is gathering wide spread attention with the major limitation to its application being its cost of operation and design considerations. While the general approach of most researches is to buttress the already known fact of the efficacy of the process, little attention is given to studying the by-products of ozone reactions with organics. The aims of this study were to investigate the efficacy of the ozonation process for removing recalcitrant phenolics: phenol, 2-chlorophenol (2CP), 4-chlorophenol (4CP) and 2,4-dichloropheno (2,4DCP) from aqueous medium with a view of understanding various reaction pathways of the process and identifying possible intermediates and residual compounds using liquid chromatography-mass spectrometry (LC-MS). The choice of the selected chlorophenols would also elucidate the role of the positioning of the chlorine atoms in determining reaction rates, pathways and subsequent mechanisms and by-products. Sequel to this, oxy-hydroxy iron in β-phase (β-FeOOH, akaganite) and various β-FeOOH bonded composites on support metal oxides (Al2O3, NiO and TiO2) were prepared via hetero-junction joining, and explored as a possible promoter to improve the efficiency of the ozonation process. Apparent first order reaction rates constants of tested phenolics was in the order 2,4-DCP > 2-CP > Phenol > 4-CP, irrespective of the tested pH. The individual rates however increased with increasing pH. The position 4 chlorine atom was found to be least susceptible to hydroxylative dechlorination. Catechol intermediate and pathway was identified as the major degradation pathway for phenol and 2-CP, while 4-chlorocatechol pathways were more important for 4-CP and 2,4-DCP. The formation of polymeric dimers and trimers by all compounds was pronounced at alkaline pH. Heterogeneous catalytic ozonation using β-FeOOH reduced ozonation time for 4-CP by 32%. Mechanism for β-FeOOH/ozone catalysis showed that the catalyst suffered reductive dissolution in acidic pH and the kinetics of 4-CP removal using the catalyst was best described using a two stage kinetic model. The first stage was attributed to heterogeneous catalysis of ozone breakdown on β-FeOOH surface generating faster reacting radicals, while the second stage was due to homogeneous catalysis by reduced Fe2+ ions in solution. β-FeOOH stabilized on NiO at a 5% ratio exhibited superior catalytic property compared to the other tested composites. Characterization by high-resolution transmission electron microscopy (HRTEM) affirmed a β-FeOOH-NiO bonded interfaced composite which was stable as a iv catalyst over four (4) recycle runs. The mechanism of operation of the composite was via an increased ozone breakdown to radicals as monitored via photoluminescence experiments. The composite material produced satisfactory results when tested on real wastewater samples. Results from this study contribute to the current understanding on reaction mechanisms for ozone with phenols and chlorophenols, for the first time monitoring time captured intermediates via liquid chromatography-mass spectrometric method, which preserves the integrity of reaction intermediates. Also this study proposes heterogeneous catalysts; β-FeOOH and β-FeOOH bonded composites as possible improvements for simple ozone based water purification systems.
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Powell, William W. "The removal of color and DOC from segregated dye waste streams using ozone and Fenton's reagent followed by biotreatment." Thesis, Virginia Polytechnic Institute and State University, 1992. http://hdl.handle.net/10919/50105.
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The decolorization of reactive dye-containing waste streams using oxidizing chemicals and the determination of the effect of the oxidizing agents on the subsequent biotreatment of the streams was investigated. Three oxidizing schemes were chosen for study: molecular ozone, base-promoted ozonation, and Fenton’s reagent (Fe²⁺ and H₂O₂). The ADMI color value of the solutions was used as the primary parameter for color comparison and dissolved organic carbon (DOC) removal was the measure of the effect of biodegradation.
Three different waste streams from a textile dyeing facility were chosen: a Navy slack washer effluent from a pad-dyeing operation, a Navy dyebath effluent from a dyejet, and a Brilliant Blue dyejet effluent. Pure dye solutions were oxidized as well to determine the effect of interfering species in the waste streams.
The results demonstrated that base-promoted ozonation was more effective than molecular ozone for the decolorization of the Navy slack washer effluent. In both cases the ADMI color value could be decreased by 82% but almost half as much ozone was necessary for the high pH trials. The high pH ozonation proved more effective for the Navy jet-dye effluent, as well, achieving a much lower color value with less ozone. Greater decolorization (96%) of the Navy jet-dye effluent was achieved by Fenton’s reagent than for either of the ozonation schemes. Ozonation of the Brilliant Blue jet-dye bath showed no dependence on pH and the color value of the solution was reduced could be 63%.
The results indicate that the dyes were selectively oxidized by ozonation and the amount of ozone required for decolorization depended mainly the initial color of the dye waste stream. The amount of hydrogen peroxide required for Fenton’s reagent oxidation depended on the initial DOC of the dye waste stream.
Oxidation of the wastewater streams proved to neither enhance nor hinder the operation of the biological reactors. The color removals by biological activity were minimal for both control and experimental reactors. Dissolved carbon removal was not enhanced by oxidative pretreatment.Master of Science
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Karat, Irma. "Advanced Oxidation Processes for removal of COD from pulp and paper mill effluents : A Technical, Economical and Environmental Evaluation." Thesis, KTH, Industriell ekologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121350.
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In Sweden, the dominating source for emissions of degradable organic substances to water is the pulp and paper industry. The organic substances increase oxygen consumption in the recipient which subsequently threatens aquatic species. Improved process engineering, process closures and use of external treatments have in recent years drastically lowered the Biological Oxygen Demand (BOD). However, the Chemical Oxygen Demand (COD) has not been reduced to the same extent, as some organic substances are more persistent and must be treated with more advanced techniques. Chemical precipitation, which can bind large parts of the remaining COD into solid matter, making it possible to be removed from the effluent by various separation technologies, contributes to an efficient COD removal. However, the direct operating cost for the treatment is high as large amount of chemicals are used in the process, and large quantities of sludge generated. In the near future EU pulp and paper industry will have to meet new regulatory demands on COD discharges, and pulp mills in Asia, South-America and Oceania will meet stringent discharge demands. It is therefore of interest to review alternative treatments in regards to technical, environmental and economical feasibility in the treatment of pulp and paper mill wastewaters. Much interest has been shown for Advanced Oxidation Processes (AOP), which is why these techniques have been evaluated in this thesis. The first part of the report consists of a literature review where processes with the following oxidants have been reviewed: 1. Ozone (O3); 2. Ozone + Hydrogen peroxide (O3/H2O2); 3. Fenton’s reagent (Fe2+/ H2O2); 4. Ozone + Ultraviolet light (O3/UV); 5. Hydrogen peroxide + Ultraviolet light (H2O2/UV); 6. Photo-Fenton’s reagent (Fe2+/ H2O2/UV); 7. Titanium dioxide + Ultraviolet light (TiO2/UV). Ozone treatment (1) and ozone in combination with hydrogen peroxide (2) were chosen for further experimental studies. The experiments were conducted at Wedecos (Xylem Water Solutions) laboratory in Germany and tested on wastewater from three different Swedish mills: A, B and C. The experimental results indicate that treatment with ozone is an efficient method for elimination of COD from pulp and paper mill wastewaters. A relatively high COD reduction (41 % for Mill A, 31% for Mill B and 53% for Mill C) was achieved for all wastewaters with an applied ozone dosage of 0.2g O3/L, without an appreciable impact on other parameters such as pH, N-tot, NO2-, NO3-, NH4+, P-tot and PO43-. There are indications that the nature of the wastewater has an impact on the COD removal efficiency and that TMP wastewater is easier to oxidize in comparison to wastewater from sulphate mills. The combination with hydrogen peroxide did not show any further COD reduction compared to ozone treatment alone, thus confirming the results Ko et al. showed in their study in 2009. Oxidation with ozone is seen as more environmental alternative in comparison to chemical treatment (precipitation/flocculation) because contaminants in the wastewater are destructed rather than concentrated or transferred into a different phase, which leads to the decrease of COD, colour and toxicity without the need to handle large amounts of sludge. However, a subsequent biological treatment may be necessary for removal of BOD as a BOD increase is registered for all wastewater treated in this study. The costs are on the other hand higher in comparison to chemical treatment even though there are indications of cases when treatment with ozone can be profitable (e.g. if the cost for sludge handling increases in the future, price for chemicals increases and electricity price decreases). There are some uncertainties regarding the system and there is no clear evidence that toxic by-products are not formed. More research must be done and more full-scale installations must be reported before the pulp and paper industry is willing to invest in oxidation technology.I Sverige, är massa- och pappersindustrin den dominerande utsläppskällan av nedbrytbart organiskt material till vatten. När det organiska materialet når recipienten ökar syreförbrukningen eftersom stora mängder syre erfordras för nedbrytningen av materialet. Detta leder i sin tur till att de vattenlevande organismerna hotas och utsätts för syrebrist. Förbättrad processteknik, ökad processlutning och utbyggnad av extern avloppsvattenrening har under de senaste åren drastiskt sänkt den biokemiska syreförbrukningen (BOD). Däremot har den kemiska syreförbrukningen (COD) inte reducerats i samma utsträckning då delar av det organiska materialet är mer persistent och måste behandlas med mer avancerad teknik. Kemisk fällning kan idag binda stora delar av det kvarvarande COD till fast material som sedan kan avlägsnas via olika separationsmetoder. En stor nackdel med den här typen av rening är att stora mängder kemikalier används som i sin tur genererar stora mängder slam som måste tas om hand, vilket introducerar höga driftkostnader. Inom en snar framtid kommer massa- och pappersbruk inom EU att möta nya regulatoriska krav för COD utsläpp, och bruk i Asien, Sydamerika och Oceanien kommer även de att möta väldigt hårda utsläppskrav. Det är därför av intresse att granska alternativa reningsmetoder och utvärdera dess tekniska, miljömässiga och ekonomiska genomförbarhet vid behandling av avloppsvatten från massa- och pappersbruk. Mycket intresse har visats för Avancerade Oxidationsprocesser (AOP), varför dessa tekniker valts att utvärderas i detta examensarbete. Första delen av rapporten innefattar en litteraturstudie där processer med följande oxidanter studerats: 1. Ozon (O3); 2. Ozon + Väteperoxid (O3/H2O2); 3. Fenton’s reagens (Fe2+/ H2O2); 4. Ozon + Ultraviolett ljus (O3/UV); 5. Väteperoxid + Ultraviolett ljus (H2O2/UV); 6. Foto-Fenton’s reagens (Fe2+/ H2O2/UV); 7. Titaniumdioxid + Ultraviolett ljus (TiO2/UV). Utav dessa valdes ozon behandling (1) och ozon i kombination med väteperoxid (2) för vidare experimentella studier. Behandlingarna har utförts vid Wedecos (Xylem Water Solutions) laboratorium i Tyskland och undersökts på avloppsvatten från tre olika svenska bruk; A , B och C. Experimentella resultat tyder på att ozonering är effektiv behandlingsmetod för reducering av COD i avloppsvatten från massa- och pappersbruk. En relativt hög COD reducering (41% för bruk A, 31% för bruk B, och 53% för bruk C) uppvisades för samtliga avloppsvatten med en tillämpad ozondosering på 0.2 g O3/L, utan någon märkbar inverkan på andra parametrar så som pH, N-tot, NO2-, NO3-, NH4+, P-tot och PO43-. Det förekommer indikationer om att typ av avloppsvatten har en inverkan på COD reduktionen och att TMP avloppsvatten är lättare att oxidera i jämförelse mot avloppsvatten från sulfatmassabruk. Kombinationen av ozon och väteperoxid uppvisade ingen ytterligare COD reduktion i jämförelse mot ozon som enda oxidant, och bekräftade därmed de resultat Ko et al. uppvisade i sin studie 2009. Ozonering ses som ett miljövänligare alternativ till kemisk rening (fällning/flockning) eftersom föroreningarna i vattnet destrueras istället för att koncentreras, vilket innebär att COD, färg och toxicitet kan minskas utan att stora mängder slam genereras. Dock kan en efterföljande biologisk behandling vara nödvändig för avskiljning av BOD då en BOD ökning uppvisats för samtliga avloppsvatten i denna studie i takt med att COD brutits ned till lättnedbrytbart biologisk material. Kostnaderna är däremot höga i jämförelse mot kemisk fällning även om det förekommer indikationer på fall när behandlingen kan vara lönsam (t ex om slamhanteringskostnaderna blir högre i framtiden, inköpspriset för kemikalier ökar och elpriset sjunker). Det råder vissa tveksamheter gällande systemet och det finns inga konkreta bevis på att toxiska biprodukter inte bildas. Mer forskning måste utföras och fler fullskaliga installationer måste rapporteras och innan massa- och pappersindustrin är villig att investera i oxidationstekniken.
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Sadrnourmohamadi, Mehrnaz. "Removal of trihalomethanes precursors from surface waters typical for Canadian prairie and shield." International water association (IWA), 2013. http://hdl.handle.net/1993/30864.
Full textAbstract:
Many Canadian water treatment plants supplied by surface waters of the Canadian Prairie and Shield have elevated concentrations of trihalomethanes (THMs), which exceed the provincial standards. These water sources are characterized by elevated levels of dissolved organic carbon (DOC) and varying levels of calcium hardness, which causes a challenge for the removal of THMs precursors.
The objective of this study was to investigate the effect of two treatment methods: chemical coagulation and pre-ozonation-coagulation on the removal of DOC as the main THMs precursor. Surface waters typical for the Canadian Prairie and Canadian Shield were used in the experiments which includes Assiniboine River, Red River, and Rainy River. The effects of different experimental conditions such as coagulant dose, coagulant type, and solution pH as well as ozone dosage on THMs removal were investigated. The structural and chemical characteristics of natural organic matter and isolated humic substances, before and after the reaction with ozone, were studied using spectroscopic techniques.
The results illustrated that the quality of source water (DOC characteristics, concentration of water DOC and Calcium) has a significant impact on THMs reduction by chemical coagulation and ozonation. Coagulation results showed that reduction of total DOC does not guarantee THMFP reduction and chemical coagulation should be optimized to remove the hydrophobic acid fraction which forms most THMs. The removal of DOC by aluminum-based coagulants was affected more by the concentration of polymeric and colloidal aluminum speciation. This finding is especially important for plants supplied by high alkalinity waters where pH adjustment is a serious challenge.
The effect of pre-ozonation on coagulation varies depending on the concentration of calcium, which has the ability to form complexes with DOC compounds promoting their removal in coagulation. For the surface water with high levels of organic carbon and calcium hardness, ozonation prior to coagulation was beneficial in terms of DOC reduction. However, it showed the opposite effect on water with high levels of DOC accompanied with low level of calcium hardness. Spectroscopic results showed that ozonation of NOM and humic substances cause a significant reduction of aromatic and highly conjugated compounds (constituting primarily the hydrophobic acid fraction).February 2016
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Brown, Amy Patricia. "Application of Ozone in Dissolved Air Flotation (DAF) for Enhanced Removal of TOC and Suspended Solids in Pulp and Paper Wastewaters." Master's thesis, Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/406436.
Full textAbstract:
Environmental EngineeringM.S.Env.E.
Pulp and paper mills are one of the top consumers of water related to industrial manufacturing, which ultimately leads to a large volume of heavily contaminated wastewater. This discharged effluent can have a harmful effect on the receiving aquatic environment and cause further ramifications downstream. Thus, a technically feasible and cost effective treatment solution for safe release from the mill is essential. Dissolved air flotation (DAF) has many applications and involves the formation of air microbubbles triggered by a drop to atmospheric pressure. When introduced into the wastewater, these microbubbles attach to the floc particles present and float to the surface. Another water treatment technology is ozone, a powerful oxidant, and has been widely used in water and wastewater treatment over recent decades, including color reduction in pulp and paper mill wastewater treatment. This thesis studied the effect pre-ozonation has on the DAF process in treating pulp and paper mill secondary effluent. Wastewaters from three mills with different initial water quality parameters were used, especially chemical oxygen demand (COD), turbidity, and color. The most suitable coagulant and coagulant aid, aluminum chlorohydrate and cationic polymer NS 4700P respectively, were selected, and an effective bench-scale experimental procedure was established. Pre-ozonation did not reduce the need for coagulant due to little change in the overall COD, color, or turbidity removal. However, ozonation did reduce color before coagulation, and the ultimate target removal of COD to 90 ppm was met with the conditions chosen.
Temple University--Theses
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Sathiyamurthi, Ramasamy. "A quantitative approach on understanding emission and removal of trace gases and atmospheric oxidation chemistry in remote and suburban forest." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217213.
Full text
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Trevizani, Jéssica Luiza Bueno. "Descoloração e degradação do azo corante vermelho BR por ozonização." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1364.
Full textAbstract:
CAPESA indústria têxtil é responsável pela geração de efluentes com elevada carga orgânica, cor e toxicidade. O principal objetivo deste trabalho foi avaliar a eficiência de remoção de um corante azo-reativo (Vermelho BR) pelo processo de ozonização em variações de pH e concentração inicial do corante para duas soluções: solução aquosa acrescida de corante (Solução 1) e solução de efluente sintético acrescido de corante (Solução 2). Para tal, os ensaios foram realizados em pH 4 (ácido), pH 7 (neutro) e pH 10 (alcalino) e a concentração inicial do corante foi variada em 50, 100 e 150 mg/L. As coletas foram realizadas de 15 em 15 minutos e os parâmetros analisados para Solução 1 foram: temperatura, remoção de cor, turbidez, ozônio dissolvido, off-gas e ozônio consumido; para Solução 2, além desses parâmetros também foi analisada a remoção de matéria orgânica (DQO). O tempo de ozonização ocorreu até a remoção significativa da cor (>90%) e variou entre 60 e 240 min. A produção de ozônio utilizada neste trabalho foi a máxima obtida pelo gerador de 0,702 gO3/h em vazão máxima de ar (15 L/min). A eficiência máxima de transferência de ozônio para o líquido foi de 73% em meio alcalino (pH igual a 10) e mínimas em condições ácidas (pH igual a 4) para ambas as soluções analisadas. Através da aplicação do delineamento de composto central (DCC) e dos gráficos de superfície de resposta, pode-se verificar a influência dos fatores concentração inicial de corante (Fator 1) e pH (Fator 2) na variável resposta remoção de corante. Dessa forma pode-se observar que a influência da concentração inicial do corante é mais significativa do que a influência do pH na eficiência de remoção do corante. A eficiência máxima de remoção foi de 98% para Solução 1 e para Solução 2 em pH 10 e 4 respectivamente e com concentração inicial de corante de 50 mg/L. A fim de analisar a toxicidade das soluções, antes e após a ozonização, foram realizados testes de toxicidade aguda com o organismo teste Daphinia similis e verificou-se toxicidade em todas as amostras analisadas. Ao longo deste trabalho pode-se observar que a ozonização tem resultados eficientes na oxidação do corante têxtil Vermelho BR em todas as variações de pH e concentração de corante.
The textile industry is responsible for generating wastewater with high organic content, color and toxicity. The direct objective of this study was to evaluate the hum dye removal efficiency azo-Reactive (Red BR) by ozonation process in pH variations and initial dye concentration. For two solutions: dye plus aqueous solution (Solution 1) and synthetic effluent solution plus dye (Solution 2). To this end, tests were performed at pH 4 (acid), pH 7 (neutral) and pH 10 (alkaline) and the initial dye concentration varied among 50, 100 and 150mg / L As samples were performed from 15 to 15 minutes and the parameters were analyzed. for Solution 1 were: temperature, color removal, turbidity, dissolved ozone, off-gas and ozone consumed. For solution 2, besides these parameters, was also analyzed the removal of organic matter (COD). The rate of ozonation has occurred up to a significant removal of color (> 90%) and between 60 and 240 min.The Ozone production used in this work was a Maximum obtained with Generator 0702 GO3 / h in air flow Maximum (15 L / min). The Maximu m Efficiency of transfer Ozone to the net was 73% in alkaline medium (pH 10) and minimum under acidic conditions (pH 4) For both analyzed solutions. through the application of the central compound design (DCC) and Polling Surface Graphics, it is possible to check the initial dye concentration factors of influence (Factor 1) and pH (Factor 2) in the Variable Voting dye removal. This can be observed as forms of Influence of the initial dye concentration and more significant is that the influence of pH dye removal efficiency. Maximum efficiency removal was 98% For Solution 1 and 2 sat pH 10:04 and initial concentration of dye 50 mg / L. In order to analyze the toxicity of solutions, the before and after process of ozonation, tests were performed as toxicity test with the body similis daphinia and found toxicity at all samples. During this work, it was observed that the ozonation has results in efficient oxidation of dye textile Red BR in all pH variations and dye concentration.
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Carrasco, Galleguillos Félix Marcial. "Mejoras en la señal satelital de dióxido de azufre de megafuentes en Chile central." Tesis, Universidad de Chile, 2012. http://www.repositorio.uchile.cl/handle/2250/111530.
Full textAbstract:
Ingeniero Civil MatemáticoMagíster en Meteorología y Climatología
A lo largo de Chile existen diversas fuentes de dióxido de azufre (SO2) de origen antrópico (fundiciones de cobre, termoeléctricas, etc.) como de origen natural (volcanes, proceso biogénicos, etc.). En Chile, se estima que durante el año 2005 las fundiciones de Caletones, Ventanas y Chagres emitieron 77GgS en conjunto, cantidad similar a las emisiones totales de países desarrollados. Dados los impactos sobre la salud humana, los ecosistemas y el clima asociados al SO2 y compuestos oxidados de azufre, se requiere contar con mediciones confiables de SO2 de manera de tener un control sobre la abundancia, distribución y emisiones. El ozono (O3) y el SO2 tienen líneas espectrales de absorción similar en el ultravioleta (UV), siendo el O3 mucho más abundante que el SO2. Este último, se comenzó a estimar como una corrección a la estimación de carga atmosférica de O3 en la década de 1980, donde la carga atmosférica de un compuesto corresponde a la integral en la vertical de la concentración del compuesto, medido en moléculas/cm2 o Unidades Dobson (1 DU=2.69×1016 moléculas/cm2). Subsecuentemente, la técnica de filtrado se ha mejorado pudiendose hoy registrar la carga de SO2 con un error de fondo de 0.2 DU. Operacionalmente, se supone un perfil basado en mediciones hechas en EE.UU. En este estudio se analiza la validez de suponer el mismo perfil en la zona centro de Chile, caracterizada por una compleja circulación debido a su topografía, otorgándole variedad de forma y distribución a los perfiles en la zona de estudio. La metodología plantea usar combinadamente un modelo de transporte de baja resolución horizontal (∼ 10km), para calcular los perfiles de SO2 en la zona de estudio y un modelo de transferencia radiativa, para estimar los efectos de la dispersión y absorción del SO2 en la atmósfera. El modelo de transferencia radiativa, permite simular la medición satelital, considerando el perfil modelado. De esta manera es posible estimar la sensibilidad de la estimación de carga de SO2, con respecto a los perfiles a lo largo de Chile Central. Las estimaciones de SO2 se corrigen al cambiar el perfil de SO2 y adema ́s se implementa un filtro estadístico que elimina aquellos datos fuera de los percentiles 1 y 99 de la población y que además elimina la variabilidad mensual, a través de un filtro de Fourier, considerando que el tiempo de residencia del SO2 es del orden de días. El resultado principal es la corrección de las estimaciones de SO2 en la zona central de Chile, con una sensibilidad entre un 40 %-80 %.
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Melgão, Marta Filipa Banha. "Detecção remota da coluna de ozono recorrendo a irradiâncias espectrais medidas à superfície." Master's thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/12384.
Full textAbstract:
O trabalho realizado tem como objetivo principal a determinação dos valores da coluna de Ozono Atmosférico sobre Évora a partir de irradiâncias espectrais medidas à superfície. O instrumento utilizado foi um radiómetro espectral (Multi-Filter Rotating Shadow Band Radiometer YES MFR-7), instalado no Observatório do Centro de Geofísica de Évora. O estudo realizado compreendeu os anos de 2005 a 2008 em determinados períodos de cada ano, não tendo sido utilizadas medições contínuas devido a falhas do instrumento.
Utilizaram-se também dados do instrumento OMI localizado a bordo do satélite AURA, com uma periodicidade diária, de modo a comparar com os valores obtidos com a metodologia apresentada aqui, utilizando observações de superfície.
A comparação realizada evidenciou a concordância na evolução anual e sazonal do conteúdo da coluna total de Ozono anualmente e sazonalmente. Os resultados obtidos revelaram uma correlação linear significativa entre ambas as séries (O3_OMI e O3_MFR-7) e coeficiente de correlação, R=0.8.; ### ABSTRACT: The purpose of the study is to determine the total ozone column content over Évora, from spectral irradiances measured at the surface. The instrument used was a spectral radiometer, (Multi-Filter Rotating Shadow Band Radiometer YES MFR-7), installed in the Observatory of the Évora Geophysics Centre. This study was carried out for four years, 2005 to 2008, in some distinct periods each year, due to lack of data in the rest of the time.
Satellite data from the Ozone Monitoring Instrument (OMI) onboard AURA satellite, were used too. Satellite remote sensing values are obtained once a day in order to compare with the corresponding daily mean calculated from the surface instrument.
A comparison of the evolution of the total ozone column was done per year and per season. The results of this study reveal a strong linear correlation between the two series (O3_OMI e O3_MFR-7), with a correlation coefficient R=0.8.
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Zhou, Shuntai, Alvin J. Miller, and Lon L. Hood. "A partial correlation analysis of the stratospheric ozone response to 27-day solar UV variations with temperature effect removed." AMER GEOPHYSICAL UNION, 2000. http://hdl.handle.net/10150/624005.
Full textAbstract:
Observational detection of upper stratospheric ozone responses to 27-day solar ultraviolet (UV) variations is often inhibited by larger, dynamically induced ozone variations, which result mainly from the temperature dependence of reaction rates controlling the ozone balance. Here we show that partial correlation coefficients of solar UV and tropical upper stratospheric ozone (1–5 hPa) with the temperature effect removed are larger (07–0.8) than are total correlation coefficients of ozone and solar UV (0.4–0.6). The phase lag of ozone relative to solar UV is also increased, and the maximum ozone-UV correlation is obtained at higher altitudes, as compared with correlation analyses using ozone and solar UV data alone. Assuming that temperature variations are not forced by solar UV variations, the ozone sensitivity to solar UV and temperature can be calculated using a linear multiple regression model. The ozone sensitivity to solar UV is generally independent of time periods used for the analysis. However, the magnitude of the ozone sensitivity to temperature at 1–2 hPa increased significantly from solar cycle 21 to solar cycle 22, possibly reflecting long-term changes in the composition of the upper stratosphere.
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Santana, Caroline Martins. "Estudo da degradação de corante têxtil em matrizes aquosas por meio dos processos oxidativos avançados O3-H2O2/UV e foto-Fenton." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-11082010-143735/.
Full textAbstract:
A indústria têxtil gera grandes volumes de efluentes com elevada carga orgânica, forte coloração e toxicidade. Neste trabalho, estuda-se o tratamento de solução aquosa contendo o corante Solophenyl Yellow Arle 154% por meio dos processos O3-H2O2/UV e foto-Fenton, avaliando-se as repostas: remoção de cor em 5 minutos, remoção de cor em 60 minutos, taxa máxima de remoção de cor e remoção de COT em 60 minutos. Os experimentos foram realizados em semibatelada com circulação usando um reator fotoquímico com campo de radiação anular coaxial, constituído de corpo cilíndrico em aço com refletor interno de alumínio para 12 lâmpadas fixadas simetricamente na superfície refletora e um tubo reator em quartzo de 0,7 L, posicionados verticalmente no eixo do refletor. Para o processo O3-H2O2/UV foram utilizadas lâmpadas Phillips TUV (36 W, 254 nm). A corrente gasosa contendo O3 foi introduzida no reator por meio de um difusor. Para o processo foto-Fenton foram utilizadas lâmpadas Sylvania (12 W cada, 300 400 nm) e concentração de Fe(II) de 0,25 mmol/L. Em ambos os processos, solução de peróxido de hidrogênio foi adicionada durante os 30 minutos iniciais de tratamento. As amostras foram analisadas por medidas de carbono orgânico total (COT) e remoção de cor (absorbância medida em 405 nm em espectrofotômetro UV-visível). Em ambos os processos utilizou-se o planejamento experimental Doehlert, definindo os valores mínimo e máximo para cada variável adotada. No caso do processo O3- H2O2/UV (ETAPA I), foram estudados os efeitos da potência elétrica total das lâmpadas (144 432 W), concentração de H2O2 (5 30 mmol/L), concentração inicial de corante (20 100 mg/L), concentração de ozônio (10 40 mg/L) e pH (3 10). No processo foto-Fenton (ETAPA II), estudaram-se os efeitos da potência (160 480 W), concentração de H2O2 (5 30 mmol/L) e concentração inicial de corante (20 100 mg/L). Os resultados da ETAPA I indicaram que o aumento da concentração do corante, em meio ácido, aumenta a remoção de cor em 5 e 60 minutos, sugerindo a eficiência da ação via ozônio molecular sob o grupo cromóforo do corante. Os melhores resultados apresentaram remoção acima de 95% em 5 e 60 minutos de tratamento. Entretanto, para a remoção de COT em 60 minutos o processo não foi eficiente, apresentando resultado máximo de 35,6%. Na ETAPA II obtiveram-se resultados menos satisfatórios para remoção de cor se comparados aos da ETAPA I (56,1% em 5 minutos e 78% em 60 minutos de tratamento), mas melhores em relação à remoção de COT em 60 minutos atigindo 45,1% de remoção. As maiores taxas de remoção de cor foram observadas nos 5 primeiros minutos de tratamento para todos os experimentos. Experimentos complementares realizados em uma terceira etapa (ETAPA III) mostraram que a aplicação do processo O3 seguido do processo foto-Fenton permitiu resultados satisfatórios tanto para remoção de cor (97,2%), quanto para remoção de COT (69,5%). O estudo da ação do processo O3 em modo contínuo e a avaliação econômica preliminar do processo integrado O3 - foto-Fenton sugerem o potencial de aplicação do tratamento integrado a indústrias têxteis.The textile industry generates large volumes of wastewater with high organic load, strong coloration and toxicity. In this work, the treatment of an aqueous solution containing the dye Solophenyl Yellow Arle 154% was studied by the O3-H2O2/UV and photo-Fenton processes, in order to evaluate the responses color removal after 5 minutes; color removal after 60 minutes; maximum rate of color removal; and TOC removal after 60 minutes. The experiments were carried out in the semi-batch mode with circulation using a photochemical reactor with annular coaxial radiation field, consisting of a cylindrical stainless steel support with an aluminum internal reflector with 12 lamps fixed symmetrically in the internal reflecting surface, and a quartz tube reactor of 0.7 L, positioned vertically along the axis of the reflector. For the O3- H2O2/UV process, Phillips TUV lamps (36 W, 254 nm) were used; the gas stream containing zone was introduced into the reactor through a diffuser. For the photo- Fenton process, Sylvania lamps (12 W each, 300 - 400 nm) and a concentration of Fe (II) of 0.25 mmol/L were used. In both cases, the hydrogen peroxide solution was added in the first 30 minutes of treatment. The samples were analyzed by the measurement of total organic carbon (TOC) and color removal (absorbance measured at 405 nm in a UV-visible spectrophotometer). In both cases the Doehlert experimental design was used, defining the minimum and maximum values of each variable adopted. In the case of O3-H2O2/UV process (PHASE I), the effects of the total electric power of the lamps (144 - 432 W), H2O2 concentration (5 - 30 mmol/L), initial dye concentration (20 - 100 mg/L), ozone concentration (10 - 40 mg/L), and pH (3 - 10) were studied. For the photo-Fenton process, the studied variables were: total electric power of the lamps (160 - 480 W), H2O2 concentration (5 - 30 mmol/L), and initial dye concentration (20 - 100 mg/L). The results of PHASE I indicated that the increase of dye concentration in acidic conditions increases color removal after 5 and 60 minutes, thus suggesting the efficiency of molecular ozone action upon the chromophore group of the dye. The best results showed color removal above 95% after 5 and 60 minutes of treatment. However, for the TOC removal the process was not efficient, with maximum removal after 60 minutes of only 35.6%. In PHASE II less satisfactory results for color removal were obtained in comparison with PHASE I (56.1% after 5 minutes and 78% after 60 minutes of treatment), but with higher TOC removal after 60 minutes, achieving over 45.1%. The highest color removal rates were observed within the first 5 minutes of treatment for all runs. Additional experiments carried out in PHASE III showed that the oxidation by O3 followed by the photo-Fenton process enabled to achieve suitable results for both color (97.2%) and TOC removals (69.5%). The study of the O3 process in the continuous mode and a preliminary economic evaluation suggests a high potential for the use of the integrated O3-photo-Fenton process in textile industries.
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YANG-CHUN-YI and 楊君毅. "Nitrogen removal of ozone." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/14107089097292343779.
Full textAbstract:
碩士國立臺灣海洋大學
輪機工程系
101
In the past study, Ozone which was proved can’t only reduce the bacteria in the air in the short time, but also neutralize and decompose toxic gas. So recently ozone has been applied to water purification processing , the disposal of the air, and industrial applications widely so that it is supposed to reduce the pollution of waste. According to the International Maritime Organization ( IMO), the exhaust of diesel engine must be followed the rules of IMO, so the study aims to utilize nitrogen remove of ozone oxidation to improve the exhaust of diesel engine under the various operating conditions. In the aim of the study, ozone to the index of nitrogen removal of ozone oxidation with the exhaust of diesel engine( CO,CO2,NOx,HC,O2) is an aly size and discussed under the setting of the various conditions. Actually, the results of the research is proved that nitrogen removal of ozone oxidation with the exhaust of diesel engine can reach the reduction of the exhaust of diesel engine and the standard level of the International Maritime Organization (IMO).
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Clifton, Olivia Elaine. "Constraints on ozone removal by land and implications for 21st Century ozone pollution." Thesis, 2018. https://doi.org/10.7916/D8709J8T.
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Ozone dry deposition, an important tropospheric ozone sink, is expected to evolve with climate and land use, but coarse representation of ozone dry deposition in most large-scale atmospheric chemistry models hinders understanding of the influence of this sink on ozone air quality. Ozone uptake by stomata, injurious to plants, has been emphasized in the atmospheric chemistry community as the predominant terrestrial ozone depositional sink. However, there is an abundance of observational evidence from monitoring sites around the world suggesting that nonstomatal deposition processes (e.g., surface-mediated aqueous reactions on leaf cuticles, reactions with soil organic matter) are important ozone sinks. With observations from one of the longest ozone eddy covariance datasets available and a model hierarchy, I find substantial variations in nonstomatal ozone dry deposition, which is a non-negligible amount of the total ozone dry deposition, and identify the individual deposition processes driving observed variability. I pinpoint the responses of ozone pollution to changes in precursor emissions, climate, and ozone dry deposition at the beginning and end of the 21st century using a new version of the NOAA GFDL chemistry-climate model that more explicitly resolves deposition processes by leveraging the interactive biophysics of the land component of the model. My work highlights that under strong precursor emission controls there is a shift in the high ozone pollution season over northern mid-latitudes to a wintertime peak, and that wintertime ozone is sensitive to ozone dry deposition due to the long ozone lifetime. For both summer and winter, I find that neglecting variations in nonstomatal deposition and dependencies on environmental conditions may hinder accurate identification of the processes driving observed trends and variability in ozone pollution. In light of the sensitivity of ozone to dry deposition during winter, I identify a need for developing observational constraints on the wintertime depositional sink.
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Liao, Jen-Sen, and 廖彥瑋. "The study of photoresist removal by ozone-water." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/21680045635042921999.
Full textAbstract:
碩士國立交通大學
電子工程系
89
The study of photoresist removal by ozone-water Student: Jen-Sen Liao Advisor：Dr.Jen-Chung Lou Department of Electronics Engineering & Institute of Electronics National Chiao Tung University Abstract The organic photoresist on silicon surface stripping procrsses that currently used in manufacturing technologies are based on dry and wet strip treatment. First, using plasma asher to removal the photoresist then used H2SO4/H2O2 to removal the residues photoresist and Di-water resing. We have studied the properties of photoresist removal by ozone-water. We let the experiments in various conditions and performed the every stripping rate of photoresist. We changed the hard bake temperature, ozone-water temperature, ozone concentration and the different photoresists. After experiments we took the samples into the microscope to observe the results and check whether damage the under layer films. Our studying evaluates the ozone-water process for photoresist removal, it has potential to reduce the cost of ownership (CoO) and throughput. In addition, it can reduce the environmental impact of the current photoresist stripping processes.
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Chen, Ji-Wei, and 陳志偉. "The Study of Photoresist Removal Mechanism by Ozone." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/35227272127949272579.
Full textAbstract:
碩士國立交通大學
電子工程系
91
The Study of Photoresist Removal Mechanism by Ozone Student：Ji-Wei Chen Advisor：Dr. Jen-Chung Lou Department of Electronics Engineering & Institute of Electronics National Chiao Tung University Abstract Ozone has been studied in replacement of the mixture of sulfuric acid and peroxide used to remove residual photoresist after lithography in traditional IC process. Researches indicated that ozone is capable of quickly stripping photoresist so that ozone may be beneficial to apply in IC process. Due to the lack of systematic illustrations related to the photoresist removal mechanism by ozone, we will thoroughly investigate this mechanism so that we can propose the better conditions of photoresist stripping process to increase the reaction rates, reduce process time and cost of ownership. In the beginning, we proposed mechanism of diffusion layer between ozone and photoresist to illustrate the key point of the reaction rates. In experiments, we changed the aqueous ozone concentrations, flow rate of ozonated water, and [OH－] to study the mass transfer of ozone through the boundary layer. The results indicated that although aqueous ozone is strong oxidant aqueous ozone concentration should be raised to increase the reaction rate limited by ozone diffusion. The reactions of ozone with photoresist take place by the mass transfer of ozone to the photoresist so the increase of mass transfer of ozone is necessary. In photoresist stripping process, it is critical to raise mass transfer of ozone to the photoresist through the diffusion layer. At last, we increased the reaction rates by megasonic agitation or stirring. Instead of raising the aqueous ozone concentrations, we conducted the reduced diffusion layer to increase the mass transfer so that a faster reaction rate was achieved. In conclusion, raising the aqueous ozone concentrations, reducing [OH－], plus megasonic agitation can effectively remove the photoresist.
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Cros, Clément. "Passive removal of indoor ozone by green building materials." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-05-931.
Full textAbstract:
Ozone is a known pollutant harmful to human health and a strong oxidizer. The use of Zero Energy Air Purification (ZEAP) materials has proven to be a viable option to reduce indoor ozone concentrations during short-term experiments. The current study focuses on activated carbon mats, and three green building materials (perlite-based ceiling tile, recycled carpet, and painted gypsum wallboard. The effects of long-term exposure of these materials to real environments on ozone removal capability, primary emissions (in absence of ozone) of carbonyls and secondary emissions of carbonyls following the use of ozone were studied. A field study was completed over a six-month period and laboratory testing was intermittently conducted on material samples. The results show sustained ozone removal capability for all materials except carpet. Carbonyl emissions are low for activated carbon in all field locations. Painted gypsum wallboard and perlite-based ceiling tile have similar overall emissions over the six-month period, but distributed differently in time, while carpet has large initial emission rates that decline rapidly but remain high compared to the other materials. This study confirms that activated carbon mats are a viable ZEAP material and that perlite-based ceiling tile could also be considered as such as it balances good ozone removal capability and low by- product emissions.text
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蕭名竣. "Removal of odorous compounds by ozone/catalyst/UV processes." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/k25nmy.
Full textAbstract:
碩士逢甲大學
環境工程與科學學系
107
Each person who always takes about 80% of the time to stay at indoor environment. Therefore, indoor air quality is increasingly valued. Because the odorous compounds in the room won’t only cause discomfort to the human body and endanger the health, but even cause death. Moreover, the purifier on the market have different functions. Most of them use activated carbon combined with HEPA (High-Efficiency Particulate Air, HEPA) filter to absorb common odorous compounds in the room. However, this technology has the question that the odorous compounds are desorbed in the indoor environment again and again. Therefore, this study proposes to treat indoor odorous compounds (Ammonia and Formaldehyde) with advanced oxidation catalytic processes. Through ozone and catalyst produce active substances, such as hydroxyl radicals are generated during the heterogeneous catalytic reaction. In addition, the free radicals use strong oxidizing power of to destroy indoor odorous compounds. The indoor odorous compounds not only can be degraded which are difficult to decompose or even mineralized into less harmful carbon dioxide and water, furthermore the re-release of the odorous compounds can be avoided. This study can be divided into two parts: (1) preparation of novel catalyst, (2) Establish an air purification system with a laboratory-scale and match with advanced oxidation catalytic processes to evaluate the removal efficiency of O3/UV/catalysts for odorous compounds in the room. In the preparation of the best catalyst, the specific surface area of the catalyst synthesized by DI water-ethanol = 50% : 50%, sonochemical 1 hr, 1 wt% CIT (sodium citrate), calcination temperature 400C is the largest. Based on the above parameters, manufacture four different proportions catalysts and spray on the non-woven filter to evaluate which kind of catalyst is required for the different odorous compounds. Use catalyst D (catalyst preparation D) has the best removal efficiency in O3/UV/catalyst oxidation combination. Under advanced oxidation catalysis, the odorous compounds ammonia and formaldehyde can reach 79.1% and 89.1% removal efficiency in 10 minutes. In the catalyst stability test, the O3/UV/catalyst D oxidation combination showed catalyst deactivation in ammonia and formaldehyde test at 195 and 255 min, respectively, and could not achieve a better removal effect. The removal efficiency of the odorous compounds in different oxidation combinations in the order of O3/UV/catalyst> UV/catalyst> O3/catalyst O3/UV. In generally, the O3/UV/catalyst oxidation process is used to remove the odorous substance can not only oxidize the odorous compounds into harmless compounds but also avoid the doubt of secondary pollution.
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Zhan, Li Qian, and 詹麗謙. "Removal of odor, color, and bacteria by microbubbled-ozone." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/32165730167928100259.
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Che, Shao Ming, and 邵明哲. "The Feasibility Study of Using Ozone Bubble for Photoresist Removal." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/83154548599552691577.
Full textAbstract:
碩士東海大學
環境科學系
93
Lithography is critical process for semiconductor device fabrication. In order to maintain defect -free condition for the subsequent processes, photoresist must be removed completely, there by making the photoresist stripping an important step. The conventional photoresist stripping uses the SPM method, which requires wafer submersion into a mixture of sulfuric acid and hydrogen peroxide solution in 120 ~ 150℃ for 10 ~ 15 minutes to oxidize photoresist. The method is generally considered on environmentally unfriendly process because large volume of chemical wastewater is generated. Alternatively, ozone as a strong oxidizer can decompose photoresist into smaller molecules through direct or indirect oxidation, and has shown high potential to replace the SPM process. In this study, ozone in the forms of aqueous solution and bubbles was used to remove photoresist counted on 20-mm wafers. The optimum stripping conditions were evaluated, and the physical and chemical factors that influence the reaction mechanisms were observed. Also, thermal desorption coupled with atmospheric pressure ionization mass spectrometry (TDS-APIMS) was used to analyze the organic residual on the surface of the witness wafers to verify the efficiency of the ozonation process. Results show that the best stripping rate occurred when the aqueous level was 4 cm above the bottom of the wafer. The average stripping rate of 426 Å/min was achieved at 0~3 min while that of 686 Å/min was achieved at 0~6 min. Under this condition, the DUV photoresist could be completely removed in 12 min. When the aqueous temperature was elevated to 80 ℃, the stripping rate was enhanced to 2019 Å/min, and photoresist could be clean in 6 min. The TDS-APIMS analysis indicates that CO2 was the primary end-product, with a desorption pattern similar to that of SPM process. Furthermore, removal of photoresist by ozone bubbles appeared to be more effective than removal by aqueous ozonation, suggesting other indirect oxidation mechanisms absence in aqueous ozonation. This study has therefore demonstrated that proposed technique could be as effective as the conventional SPM method, but is much more environmentally benign since ozone rapidly decays in the spent wastewater. Key word：ozone﹑photoresist stripping﹑stripping rate
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Pei, Hsieh Ching, and 謝靜佩. "The removal efficiency of indoor VOCs by ozone air cleaners." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/72521279360792371673.
Full textAbstract:
碩士國立臺灣大學
環境工程學研究所
91
We use large environmental testing chamber to investigate the emissive characteristics of ozone air cleaners and to evaluate the removal efficiency of VOCs by ozone air cleaners and ozone concentrations on human health effects.After collecting the related information, we chose six ozone air cleaners of different brands. Ozone air cleaners have been claimed to remove the VOCs in indoor environment . We selected six ozone air cleaners of different brands for the test . The temperature was 25±5℃and the relative humidity was 60±5% , putting the tested ozone air cleaner into the large environmental testing chamber under airtight condition . Ozone concentration was measured using API Model 400A Ozone Analyzer . The experiments showed that ozone concentrations of No.1-No.5 rose sharply at the beginning and concentrations ranged from 200ppb to 2000ppb . No.6 got a control device to limit ozone concentrations and made it rise slowly. We applied the ozone generation-decay model to calculate the ozone emission rate E and the ozone decay constant kd . The experimental results showed that the ozone emission rate E ranged from 0.31 to 5.34 mg/hr , and the ozone decay constant kd ranged from 0.077 to 1.148hr-1 .According to the ozone generation-decay model , the ozone concentration curves and the maximum concentrations were chamber-volume and air exchange rate(ACH) dependent . The results indicated that ozone concentration decreased with both the chamber volume and air exchange rate (ACH) . We selected toluene and formaldehyde as the tested VOCs , in the experiment of the removal efficiency by ozone air cleaners . A series of experiments were performed in the sealed chamber whose temperature was 25±5℃ and the relative humidity was 60±5% . The background decay rate of toluene was 34.13% , and the removal efficiency of toluene by six ozone air cleaners ranged from 1.09% to 16.54% . When ACH of the tested chamber was 0.72hr-1, toluene concentration decreased to 0ppm 2 hours later. We used the reaction constant that ozone reacted with toluene to calculate the removal rates of toluene by ozone. The calculation showed that the removal rates of toluene were very low, so the removal efficiencies of toluene(1.09%-16.54%) were caused by the adsorption of plastic device itself. The background decay rate of formaldehyde was 34.28% , and the removal efficiency of formaldehyde by six ozone air cleaners ranged from 1.77% to 34.38% . When ACH of the tested chamber was 0.72hr, formaldehyde concentration decreased to 0ppm 2 hours later. We used the reaction constant that ozone reacted with formaldehyde to calculate the removal rates of formaldehyde by ozone. The calculation showed that the removal rates of formaldehyde were also very low, so the removal efficiencies of formaldehyde(1.77%-34.38%) were caused by the adsorption of plastic device itself. Keywords：Ozone , Large Environmental Testing Chamber , Volatile Organic Chemicals(VOCs)
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LIU, CHUN-WEI, and 劉俊煒. "The Removal of Algae Using Ozone Combined with the Environmental Friendly Catalyst." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/xze52d.
Full textAbstract:
碩士弘光科技大學
環境工程研究所
105
In the process of water treatment, ozone oxidation (O3) due to the high oxidation efficiency and disinfection capacity is better than chlorine disinfection, but ozone disinfection in the original water containing bromine ion conditions is also easy to produce another disinfection by-product - bromate (BrO3 -), while the use of ozone may increase the cost of other water purification operations, ozone in the water solubility of low shortcomings, so ozone can not operate in high concentrations of ozone conditions, if the water contains more difficult to break down organic matter to the current water plant Ozone dose and contact time may not be reduced to the target concentration. In this study, the use of continuous flow ozone reaction tank / catalytic reactor equipment, in the ozone reaction system to add titanium dioxide (TiO2) catalyst, thereby increasing the ozone in the low dose reaction, both to increase the free radical production rate, improve the ability of oxidizing pollutants. In addition, the beneficial algae in the common algae in the metabolism of organic matter and the resulting odor, is the current water treatment procedures encountered troubled reasons, the use of artificial water preparation and the actual use of eutrophic lake water for algae and other metabolites Ozone oxidation test, the experimental object is artificial cultivation of algae (microcystis (Microcystis), Chlorella (Chlorella)) and from the scene of the lake with mixed algae species of water samples.The results showed that the decomposition rate and efficiency of organic carbon in algae were significantly higher than those of ozone alone under the catalytic conditions of TiO2. Under the control of the water quality and operating conditions, the average increase was about 10 ~ 15% the decomposition rate of organic carbon in algae. In addition, for the fluorescence cytometry analysis of ozone and catalytic ozone before and after algal cell survival results, found that catalytic ozone in low-dose ozone can reach nearly 98% algae removal efficiency. Furthermore, the results of high performance molecular sieves-organic carbon detectors (HPSEC-OCD) and in-series UV photodetection (UVD) show that the molecular weight distribution of organic matter in the algae solution before and after the catalytic ozone Macromolecules organic matter by ozone or free radical oxidation after the formation of small molecules.In this study, it was found that the photocatalytic activity of TiO2 photocatalyst was enhanced by Oxygenated cells in O3 and was significantly efficient at low O3 dose, and its ozone consumption did not produce more free radicals And significantly increased.
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Chen, Jen-Jeng, and 陳振正. "The Effects of Potassium Permanganate and Ozone Preoxidation for Algae Removal by Coagulation." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/22530414630153261622.
Full textAbstract:
博士國立成功大學
環境工程學系碩博士班
93
Abstract Reservoirs are the main source of drinking water in Taiwan. However, most reservoirs are eutrophic because of pollution by domestic sewage, farming and industrial wastewater. A continuing problem for Taiwan’s water treatment plant is the presence of algae in source water. Algae in drinking water supply can cause significant problems, such as tastes and odours, production of disinfection by-products (DBPs), obstruction to coagulation, and clogging of filter. Algae removal by conventional treatment is more difficult than removal of inorganic particle, due to their low specific density, motility, morphological characteristics, and negative surface charge. Pretreatment with oxidants are commonly used in drinking water treatment process to enhance algae removal. Numerous studies have showed that preoxidants such as ozone, chlorine dioxide, chlorine, or permanganate can improve algae removal by coagulation and filtration processes. However, prechlorination may increase the alum dosage required for algae coagulation, and there are also problems of trihalomethanes (THMs) and other chlorinated organics. In this study, pilot and laboratory scale experiments were conducted to understand the effects of ozone and permanganate preoxidation on enhancing the coagulation of algae. Initial efforts were focused on comparing the effects on algae coagulation in pilot scale test. The observations in the pilot plant were further verified in the laboratory, and special attention was then paid to understand (1) the change and damage of algal cell surface by preoxidation, (2) the interactions between the algal cell and the preoxidants, and (3) the effect of preoxidation and calcium on algae coagulation. Initial results from pilot scale tests showed that both ozone and permanganate were capable of enhancing the coagulation removal of algae. Both preoxidants had an optimal dosage for algae coagulation. Although ozone preoxidation is beneficial to THMFP and A254 removal, the NPDOC in water was increased with increasing ozone dosages. This released NPDOC could inhibit the coagulation removal of algae and particulate. In contract, no significant NPDOC release was observed for permanganate preoxidation. Permanganate preoxidation was found to enhance the coagulation removal of turbidity and THMFP. On the parallel comparison in pilot test, permanganate preoxidation had a better performance than ozone in algae coagulation removal. Results from laboratory experiments showed that ozone was prone to cause the release of extracellular organic matter (EOM) into the bulk water and alter the cell wall structure. These may have detrimental effect on algae flocculation. While permanganate stressed cells to secrete EOM, which mainly remained on cell surface, and could facilitate the inclusion of MnO2 into algae floc, and improve its removal. In the presence of calcium, algae flocculation after permanganate preoxidation was more significant than the absence of calcium. However, algae flocculation was not enhanced in the presence of calcium after ozone preoxidation. This may be explained by the function of Ca2+ as a bridge between MnO2 and EOM. Generally speaking, permanganate preoxidation had a better performance than ozone on algae removal, similar to the finding of pilot scale tests. Based on the overall observations from this study, it is proposed that the effect of ozone preoxidation on algae coagulation is through cell surface charge neutralization, while permanagante is via EOM adsorption and bridging mechanism.
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Chao, Cheng Yu, and 趙正玉. "Removal of Ozone by H2O2 Absorption in a Countercurrent-flow Rotating Packed Bed." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/41266038821812843266.
Full textAbstract:
碩士長庚大學
化工與材料工程研究所
96
Ozone is used as a strong oxidant and thus widely applied in the waste and drink water treatment, sterilization and the bleaching of cloth and wood pulp. However, owing to the fact that ozone itself is toxic and the maximum concentration allowable exposure to ozone is 0.10 ppm for 8 h period and 0.30 ppm for 15 minute period, its release into the environment must be avoided. As a result, it is very essential to remove the residual ozone from air induced from these processes before discharging it to outside environment. To maintain the stable and higher ozone removal efficiency, this study adopted a countercurrent-flow rotating packed bed (RPB) to absorb ozone from air with an aqueous H2O2 solution for enhancing the ozone transfer rate. This study also investigated the effect of the operating parameters (rotor speed, flow rate of H2O2 solution, H2O2 concentration, pH of H2O2 solution, gas flow rare, ozone concentration, stationary housing radius, inner and outer radius of bed) on ozone removal. Experimental results indicated that H2O2 concentration could maintain an initial value during the absorption process. Based on this result, it may be concluded that H2O2 acted as a catalyst in the absorption process. In addition, the ozone removal efficiency appeared to increase with the rotor speed, flow rate of H2O2 solution, H2O2 concentration and pH of H2O2 solution but decrease with an increasing gas flow rate. Moreover, the obtained results indicated that the ozone removal efficiency increased as the inner radius of the bed and stationary housing radius increased and the outer radius of the bed decreased. Furthermore, a countercurrent-flow RPB provides more than 95% removal efficiency for ozone absorption using H2O2 solution, suggesting that a countercurrent-flow RPB has a great potential in the removal of ozone from the exhausted gases.
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Chin, Adeline S. "Evaluation of the removal of disinfection by-products precursors in Seymour water with ozone, UV and the advanced oxidation process ozone-UV." Thesis, 2003. http://hdl.handle.net/2429/15301.
Full textAbstract:
This research evaluated the treatment potential of ozone (O3), ultraviolet irradiation
(UV) and the combined O3-UV advanced oxidation process (AOP) in the removal
of two classes of disinfection byproduct (DBP) precursors (quantified as the
trihalomethane formation potential (THMFP) and haloacetic acid formation potential(
HAAFP)) from water samples obtained from the Seymour Reservoir near Vancouver,
Canada. The water from this source, which provides 40% of the drinking water
for the Greater Vancouver Regional District, is characterized by low pH (6.4) and low
total organic carbon (1.3 — 3.3mg/L) [1]. Laboratory batch scale experiments were
carried out at various UV and O3 dosages in order to monitor the reaction kinetics.
The combined O3-UV treatment significantly reduced the concentration of both
DBP precursors. The reduction is attributed to the mineralization of the total organic
carbon (at a rate of 0.044±0.02 minute- 1) and changes in organic constituents (~ 78%
decreased in UV254 absorbance). After 30 minutes of O3-UV treatment, THMFP
and HAAFP were reduced by approximately 80% and 70%, respectively. Ozone
treatment alone provided roughly 50% reduction of both THMFP and HAAFP after
30 minutes of ozonation. Therefore, the O3 treatment proved not to be as effective
as the combined O3-UV AOP. Ultraviolet treatment alone proved to be relatively
ineffective in reducing the concentrations of the DBP precursors studied. These
results indicate that the combined O3-UV AOP is a useful treatment option that
could be implemented to reduce the concentration of DBP precursors in Seymour's
water.
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Ho, Lionel S. W. "The removal of cyanobacterial metabolites from drinking water using ozone and granular activated carbon." 2004. http://arrow.unisa.edu.au:8081/1959.8/24958.
Full textAbstract:
The prevalence of the cyanobacterial metabolites: MIB, geosmin and microcystin in drinking water is a major concern to the water industry as these metabolites can compromise the quality of drinking water. Consequently, effective removal of these metabolites from drinking water is paramount. The combination of ozone (O3) and granular activated carbon (GAC) has been shown to be effective for the removal of these metabolites from drinking water. In this study, the ozonation of MIB and geosmin was affected by the character of natural organic material (NOM). In particular, NOM containing compounds of high UV absorbing properties and high molecular weight (MW) resulted in greater destruction of MIB and geosmin due to the formation of hydroxyl (OH) radicals. In addition, alkalinity also affected the ozonation process, with waters containing higher alkalinity resulting in decreased destruction of MIB and geosmin. Laboratory scale minicolumn experiments, coupled with the homogenous surface diffusion model (HSDM), were found to be ineffective in predicting the GAC breakthrough behaviour of MIB and microcystin at two different pilot plants. This can be attributed to the biological degradation of the metabolites at the pilot plants which cannot be modelled by the HSDM. In addition, the volume of GAC used in the minicolumn experiments may not have been appropriate for the predictions, rather, larger laboratory scale columns were found to be more applicable in mimicking pilot plant results. Microcystins were shown to be readily degraded by the bacteria attached to the GAC. Furthermore, the lag period prior to the onset of degradation, which is indicative of most biological degradation studies, was effectively eliminated and in one instance abated. This finding suggests that biological filtration of microcystin is practically feasible especially since the occurrence of microcystins in water supplies is seasonal. This study expands on previous research in the area of O3 and GAC for the treatment of MIB, geosmin and microcystin. With the imminent increase of the use of O3 and GAC in Australian water treatment plants (WTPs), this study provides valuable information for the use of these processes both alone and in combination, particularly since minimal research in this area has been conducted in Australia.thesis (PhDAppliedScience)--University of South Australia, 2004.
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CHEN, WU-CHAIN, and 陳五權. "The process studies for removal of aqueous humic acid by ozone-activated carbon adsorption." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/58483185989818098657.
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Cros, Clément. "The use of selective materials to reduce human exposure to ozone and oxides of nitrogen." 2013. http://hdl.handle.net/2152/21945.
Full textAbstract:
Ozone (O₃) and oxides of nitrogen (NO[subscript x]) are ubiquitous pollutants in many urban areas around the world. Though they mostly originate outdoors, human inhalation exposure to these pollutants largely occurs indoors, because of the large fraction of our time spent inside buildings. Exposure to O₃ and nitrogen dioxide (NO₂) has been associated with decreased respiratory function, onset of asthma, and cardiovascular events. Through laboratory testing, field exposure and modeling, this study evaluates the feasibility and long-term efficiency of using passive removal materials (PRMs) both indoors and outdoors for removal of O₃ and NO[subscript x]. Three photocatalytic coatings used outdoors and four indoor building materials were tested for their capacity to remove NO[subscript x] and O₃. Since materials outdoors experience a wider range of environmental conditions than indoors, their effects on NO[subscript x] removal by photocatalytic coatings were evaluated through full factorial experiments representative of summertime outdoor conditions in Southeast Texas. Photocatalytic coatings were also exposed to real outdoor environments for a year to assess their long-term viability. Indoor materials were exposed to real indoor environments for a six-month period and tested monthly for their capacity to remove O₃. Carbonyl emissions from these materials before and after exposure to O₃ were also tested at regular intervals during the six-month period. Finally, removal capacity of NO and NO₂ by new indoor building materials was tested as well. For outdoor PRMs, results suggest that the effect of certain environmental parameters (contact time, relative humidity, temperature) on NO[subscript x] removal effectiveness are consistent across different photocatalytic coatings, while other effects are coating specific. The type of semiconductor used and resistance to wear of the coating are important factors in its ability to retain removal efficacy over time. For indoor PRMs, two of the four materials tested, an activated carbon mat and perlite-based ceiling tiles, exhibited consistent O₃ removal effectiveness over time with low carbonyl emissions, both before and after ozonation. All materials except for activated carbon mat had higher post-ozonation than pre-ozonation emissions. Post-ozonation emissions were dominated by nonanal. Simulation of the use of indoor and outdoor PRMs on a model building through multi-zone/CFD modeling showed that indoor PRMs alone could lead to concentration reductions up to 18 % for O₃ and 23 % for NO₂ in rooms of the model building selected. Addition of PRMs on the outside of the building led to small reductions in pollutant concentrations in the air infiltrating into the building, leading to negligible changes in indoor concentrations.text
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Wu, Hou-Hsuan, and 吳厚萱. "Removal of organics from raw water using ozone disinfection combined with biological activated carbon process." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/fq7q3e.
Full textAbstract:
碩士國立中山大學
環境工程研究所
101
Because of the heavy rain in plum rain season recently, the water source from water treatment factory was polluted by E coli and organic. The concentration of these water quality items is higher than the standard of drinking water source quality. So, it cannot be supplied to public. In order to reduce the DBPs that caused of interaction between the remaining chlorine and organic when disinfection of water treatment plant is adding chlorine, it is very important to eliminate E coli and organic using pretreatment before the water treatment plant. We use the module of 2 processes of will ozone reactor and biological activated carbon column, the research mainly will discuss the elimination for E coli and organic efficiency from raw water. We cultivate local bacteria from the raw in biological activated carbon to increase the efficiency of AOC. For the results of this experiment, it regards creature usable carbon as AOC. For AOC, the productive yield of bacteria P17 is 2.41x106 CFU /μg acetate-C, while the productivity of bacteria NOX is 7.82×106 CFU /μg acetate-C. The above AOC values in raw water was sampling from Kao-Ping River. Therefore, the yields can be treated as AOC of Kao-Ping River. The results indicated that elimination rate of E coli reach to 99% in five minutes for the influence of ozone to E coli and total colony number. It indicates ozone is the good pre-treatment method for removal of E coli and total colony. TOC, DOC and AOC are three indicators of stands for the organic in the raw water. The elimination rate of these organic is ranging from 40 to 80%. The key operation conditions of BAC are the empty bed contact time and the concentration of ozone. We found the removal efficiency is more 10 to 20% in the way of ozone combined BAC, than the way of only BAC for treating raw water. It can be seen the ozone pre-treatment can increase the removal efficiency of AOC in followed BAC.
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Chen, Li-Cheng, and 陳力甄. "VOCs Removal and Treatment Efficiency of Effluent from Petrochemical Waste Water by Adsorption Using Ozone." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/92716418017230712163.
Full textAbstract:
碩士嘉南藥理大學
環境工程與科學系
103
In this study, volatile organic compounds (VOCs) in the raw wastewater collection system of a wastewater treatment plant at a petrochemical industrial park in Southern Taiwan were sampled and analyzed to evaluate the performance of outgassing treatment. First, stainless steel bottles were used to sample gas for analyzing various species of VOC. Considering the high relative humidity of the gas, activated carbon adsorption and ozonation were applied under varying water vapor conditions. Subsequently, activated carbon adsorption and ozonation procedures were combined and assessed for its effectiveness in removing VOCs following the removal of water vapor from VOCs. The study results show that among the 84 types of VOC detected in the wastewater inflow fugitive species sample, benzenic VOCs (ethylbenzene, o-xylene, m,p-xylene, toluene, benzene, and styrene) and alkyl halide VOCs (tetrachloroethene, chlorobenzene, trichloroethylene, carbon tetrachloride, 1,2-dichloroethylene, and chloroform) were the most common. The concentration of fugitive total VOCs in the inflowing water ranged between 98.3 and 874.9 ppm. When the fugitive VOCs in the wastewater were controlled, the reduction rate results differed significantly before and after removing the water vapor from the fugitive gas. The studied effect shows that the adsorption results of the activated carbon can be improved after removing the water vapor (on average, the reduction rate increased to 72.8%). In addition, regarding the inflow outgassing treatment effects under different ozone supply conditions and after mixing with oxides, the reduction rates were 62.3%–78.7%, 71.8%–85.4%, and 71.4%–97.3% at ozone production rates of 15, 30, and 45 L/min, respectively. Regarding the serial treatment effects obtained from combining ozonation and activated carbon adsorption, the total VOC reduction rates by oxidation and adsorption were 83.8%–99.0% (average: 95.0%), 86.1%–96.3% (average: 92.7%), and 91.1%–99.3% (average: 96.0%) for ozone generation rates of 15, 30, and 45 L/min, respectively. In the test performed in this study, when water vapor interference was removed before conducting VOC adsorption treatment with activated carbon, the adsorption effect was effectively enhanced, thus prolonging its utility. An ozone production rate of 30 L/min was the optimal oxidation condition in the test. Further combined with the ozonation and activated carbon adsorption conditions, the ozone production rate of 45 L/min produced a more stable treatment effect.
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Chang, Hui-Ning, and 張惠寧. "Using Bimetal Oxides Granular Activated Carbon/Ozone (BM-GACs/O3) process for Humic Acids Removal." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/32814012549051271827.
Full textAbstract:
碩士弘光科技大學
環境工程研究所
98
The purpose of this research is to investigate bi-metal oxide-granular activated carbon (BM-GACs) combining with ozone (BM-GACs/O3) for the removal of humic acid (HA) from wastewater. In this study, the metal oxide coated activated carbon preparation, including (1) nano metal oxide coated activated carbon (NM-GACs): Mn-GACs, Ce-GACs and Fe-GACs and (2) bi-metal metal oxide coated activated (BM-GACs): MnCe-GACs, FeCe-GACs and FeMn-GACs.Preparation conditions considered in this study including (1) types of metal salts (chloride and nitrate salts) (2) temperature (200 and 300℃) and (3) pH (pH 1~2 (unadjusted pH) and pH 10). The scanning electron microscope images show the metal oxides coated on the GAC surface for BM-GACs. BM-GACs/O3, BM-GACs, GAC/O3, GAC and O3 processes for humic acids were investigated in the research, Factors affecting removal such as preparation methods, Cu(II), salts, catalysts dose and ozone dosage were investigated as well. The study concluded that bimetallic nano-particles coated on activated carbon help to improve the handling of activated carbon on the HA removal efficiency.The removal efficiency of BM-GACs/O3 is better than that of GAC/O3 and O3 processes. The higher pH solution has higher removal of HA. A higher dosage of BM-GACs and ozone has a better HA, TOC and COD removal as well. In conclusions, BM-GACs/O3 process has good HA, TOC and COD removal.
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Yeh, Gwo-Dong, and 葉國棟. "The Study on The Removal of 2,4-Dichlorphenol from Aqueous olution by Ozone and Fluorocarbon." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/81195773754273269830.
Full textAbstract:
碩士國立交通大學
環境工程研究所
82
Ozone, due to its powerful oxidation potential, is considered to be an alternative for the refractory compounds. It has been limited hower, because of ozone's low solubility in water and high charge of equipment, so it can't be extensively in wastewater process. Two-phase ozonation system is a new method for the removel of organic pollutants from wastewater. This system consists of a chemical extraction from the aqueous phase accompanied by oxidation by ozone in both the solvent and aqueous phase. The experiments performed in this study, were preliminary investigations into this semibatch system. In this study a Taguchi Styled design of experiment is selected to identify the significant factors and establish the optimal combination of process parameters of the novel method. The results indicate that the optimal combination represents as follow: agitated level( 1000 rpm), flow rate of the feed gas( 800 ml/min), ozone production rate( 200 Volt), 2,4-dichlorphenol concentraction( 100 mg/L), pH value( 7.5 ), Ion strength( 0.01 M), reaction temperature( 20 ℃). However, it is suggested that at the begin of reaction, the ozone mass- transfer controlled mechanism is predominant, then we find the limit rate mechanism that is changed controll by ozone-reaction- rate . Secondly, under the optimal condition, the pseudo-first order kinetic rate constant is 0.145 l/min, the dosage of ozone for the decomposition of 2,4-dichlorphenol is 5.24 m mole O3/m mole 2,4-dichlorphenol, the mineralization of 2,4-dichlorphenol is about 21.5% and the production of the chlorine ion is 88%.
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Darling, Erin Kennedy. "Impacts of a clay plaster on actual and perceived indoor air quality." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-08-4038.
Full textAbstract:
Passive removal materials (PRMs) are building materials or furnishings that can effectively control indoor pollution without substantial formation of chemical byproducts and without energy penalty. To assess clay wall plaster as an effective PRM for improving air quality by controlling ozone, perceived air quality (PAQ) was determined in the presence of eight combinations of an emitting and reactive pollutant source (new carpet), clay plaster applied to gypsum wallboard, and chamber air with and without ozone. A panel of 18 to 23 human subjects assessed air quality in twin 30 m3 chambers using a continuous acceptability scale. Air samples were collected immediately prior to panel assessment to quantify concentrations of C5 to C10 saturated n-aldehydes and two aromatic aldehydes that are commonly produced by reaction of ozone with carpet. Perceived Air Quality was most acceptable and concentrations of aldehydes were lowest when only clay plaster or both clay plaster and carpet were present in the chambers without ozone. The least acceptable PAQ and the highest concentrations of aldehydes were observed when carpet and ozone were present together; addition of clay plaster for this condition improved PAQ and considerably decreased aldehyde concentrations.
Ozone deposition and byproduct emissions of the clay wall plaster were also assessed using 48 liter stainless steel chambers. Clay plaster applied to gypsum wallboard that had been exposed in a test house (UTest House) for one year effectively removed 88% of the ozone, and emitted high aldehyde concentrations when exposed to high purity air that did not increase when the material was exposed to ozone. The outcome of these experiments leads to speculation that the clay plaster adsorbed contaminants in the test house and then re-emitted them upon exposure to clean air in the small chambers.text
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Gall, Elliott Tyler. "Ozone transport to and removal in porous materials with applications for low-energy indoor air purification." 2013. http://hdl.handle.net/2152/21927.
Full textAbstract:
In the U.S. and other developed countries, humans spend the vast majority of their time within the built environment. As a result, a substantial portion of our collective exposure to airborne pollutants, even those of outdoor origin, occurs in indoor environments. In addition, building construction materials and operational practices are changing as we endeavor to reduce the energy burden of the built environment. These changes result in barriers and opportunities in mitigating exposure to indoor pollutants and the accompanying implications for human health. This dissertation advances knowledge regarding low-energy control of indoor ozone. Ozone is often considered a pollutant of outdoor concern. However, ozone in indoor environments presents important challenges regarding exposure, intake, and chemistry in the built environment. The investigations in this dissertation extend the state understanding of indoor transport and transformation of ozone, and the potential for using material-surface interactions in buildings to suppress concentrations of indoor ozone. The first objective relates to the determination of magnitudes of ozone removal and product emissions at room or building scales. This objective provides new data on reactive uptake and product generation in large-scale environments, develops Monte Carlo models describing indoor ozone removal by materials in homes, and compares active and passive methods of indoor ozone removal. The second objective addresses the need to develop improved air cleaning materials through experiments and modeling that address material-ozone reactions in porous materials. This objective advances the state of modeling heterogeneous reactive uptake of ozone by characterizing material physical properties and transport phenomena, determining their impact on ozone removal, and using these data to develop a more mechanistic model of material-ozone reactions. Ultimately, these investigations advance the engineering concepts that support the development of passive indoor pollutant controls, an important tool for reducing concentrations of indoor pollutants while supporting low-energy building initiatives. The combination of experimental characterization of ozone deposition velocities and product emission rates, whole-building Monte Carlo modeling, and mechanistic material/pollutant models provide important new data and approaches that expand the state of knowledge of the fate and transport of reactive pollutants in indoor environments.text
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Mooketsi, Olebogeng Ishmael. "Evaluation of ozone for the removal of phenolic compounds in wastewater from the Merisol Plant (Sasolburg)." Thesis, 2009. http://hdl.handle.net/10539/6713.
Full textAbstract:
Ozone was evaluated for the removal of phenolic compounds in wastewater from
the Merisol Plant. Oxidation was conducted under both acidic (pH = 4.70) and
basic (pH = 10.45) conditions. Phenol and acetic acid (as well as traces of formic,
butyric and propionic acids) were identified as major components in the Merisol
effluent. The results from the study have indicated that the phenol concentrations
in the Merisol effluent were reduced from an average of 355 mg/L to below
detectable levels within 60 min of oxidation period under both acidic and basic
conditions. Furthermore, the effluent COD concentration was reduced from
approximately 1200 mg/L to: 678 mg/L at 40 ppm O3; 590 mg/L at 80 ppm O3;
and to 579 mg/L at 120 ppm O3 under acidic conditions. Under basic conditions,
the effluent COD concentration was reduced to: 656 mg/L at 40 ppm O3; 510
mg/L at 80 ppm O3; and 397 mg/L at 120 ppm. These results were well below the
required 1000 mg/L COD specification level. Moreover, the results also indicated
that oxidation of the Merisol effluent sample under basic conditions yielded better
results when compared to oxidation under the normal pH of the effluent
(acidic).The degradation products of phenol ozone oxidation were identified as
formic, butyric and propionic acids. These acids occurred in various proportions
during the oxidation and were also removed during the process.
In conclusion, ozone oxidation technology has proven to capably treat the Merisol
effluent to the required specifications. This technology may be applied to increase
the degree of compliance of the Merisol Plant and that of Sasol One with regard to
the Department of Water Affairs and Forestry (DWAF) phenol specification under
the discharge water licence conditions.
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Chen, Hsuan-yu, and 陳宣宇. "The impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls generation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/17299409168370140377.
Full textAbstract:
碩士國立高雄大學
土木與環境工程學系碩士班
99
The heating, ventilation and air conditioning (HVAC) system is very important for hot and moist areas, especially in Taiwan. According to the report from USEPA, people stay in indoor spaces for most of their time. Therefore, a study of HVAC system impact on indoor air quality is needed. This study aims to find out ozone removal rates and corresponding carbonyls generation by ozone reaction with HVAC filters in different types of building, i.e.: shopping mall, school, official building, etc. The relationship between dust properties and ozone removal rates along with carbonyls generation could be found by the analyses of organic carbon proportion, specific surface area and types of functional groups on dusts sorbed on filters. This study was conducted in a small-scale environmental simulation chamber. Ozone generator, mist humidifier, air-cooled dryer and heater were used to generate input ozone-air. An air pump was utilized to sample the air inside the chamber into sampling tubes. Finally, the sample inside sampling tubes were injected into gas chromatography (GC) and analyzed by mass spectrometry (MS). The result showed that the ozone removal efficiency in mall, school, activated carbon filter of school and official building ranged from 46% to 56%, 11% to 14%, 91 to 92% and 8% to 9%, respectively. The concentration of carbonyls generation in mall, school, activated carbon filter of school and official building are 17.2 to 26.9 μg/m3, 2.2 to 3.9 μg/m3, 83.7 to 89.5 μg/m3 and 1.4 to 1.7 μg/m3, respectively. In this study, the result shows a significant correlation between ozone removal efficiency and carbonyls generations on filters, and between the composition of organic carbon on filters and ozone removal efficiency and carbonyls generations. However, the results do not show any significant positive correlation between surface areas of dusts and ozone removal efficiency and carbonyls generations. It is beneficial to remove some part of ozone when ozone passing through HVAC filters. However, there are lots of harmful compounds, carbonyls (such as formaldehyde) produced and emitted into indoor space at the same time. Therefore, the model of ozone reaction with HVAC filters along with carbonyls generation on HVAC filters is very important in future studies.
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Chen, Shih-Sheng, and 陳仕昇. "The Removal Efficiency and Distribution of Suspended Particles and Ozone in Photocopy Room by Negative Air Ions." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/rkntbs.
Full textAbstract:
碩士國立臺北科技大學
建築與都市設計研究所
95
With the advancement of technology, people rely heavily on modern equipment, office of photocopying machines dispersion of pollutants in indoor air pollution caused a major reason for the pollution can not be removed, how to improve indoor air environment is an urgent need to address the problem. Therefore, this study enclosed photocopies of indoor space measured in MapInfo data presentation software stack, pollution to provide quantitative understanding of the field operation of the photocopying pollutant concentration and distribution, follow-up by NAI and pollutant respond, evaluating the removal efficiency and distribution of suspended particles PM2, PM10 and Ozone by Negative Air Ions (NAI). The conclusions were as follows: 1. The NAI removal of suspended particles PM2 reached 67 %, the removal of suspended particles PM10 reached 50 %. The overall effect is very significant; and the NAI for small particles removal of a better result. 2. Experimental control group showed that the natural attenuation of ozone, The NAI removal efficiency of ozone only 9%. Estimating indoor ventilation is the main reason the rate is too low, the ventilation was necessary to achieve the targets for improvement. 3. The NAI density would along with the negative ion generator of distance and have a regional distribution, the difference of humidity will affect the NAI density with distance decay rate, and the difference of temperature to NAI density don''t have special influence.
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"The Effects of Different Particle Size of Nano-ZnO and Alumina-based Catalysts on Removal of Atrazine from Water with Ozone." Thesis, 2015. http://hdl.handle.net/10388/ETD-2015-12-2380.
Full textAbstract:
Due to the widespread application of pesticides and herbicides in agricultural industries, these substances have been highlighted as emerging contamination of natural ground and surface water resources. Conventional water treatment processes are only effective in removing emerging contaminants in water.
The mechanism of degradation of organic impurities present in water using ozone is known to either directly involve the ozone molecule or to occur by the indirect effect of free hydroxyl radicals (•OH). The latter are produced in the radical chain reaction of ozone decomposition.
A series of experiments were carried out to investigate the effects of particle sizes of nano-ZnO catalysts on removal of atrazine (ATZ). Nano-ZnO catalysts increase the rate of ozone decomposition and atrazine removal by production of hydroxyl radicals as oxidative intermediates. However, different particle sizes have a minimal effect on the rate of ozone decomposition and atrazine removal. It is believed that molecular ozone is adsorbed on the surface of nano-ZnO followed by the oxidation of the ozone molecule. This leads to the production of OH radicals. Therefore, it is reasonable to assume that reaction is carried out in the bulk of the solution and the rate is independent of catalyst’s surface area. This is probably the reason for similar reaction rates of different particle sizes of nano-Zno catalysts.
Additionally three different metal oxides (ZnO, Mn2O3 and Fe2O3) loaded on ƴ-alumina and ƴ-alumina (metal oxide-free) were used in catalytic ozonation of aquatic atrazine samples. The findings substantiate the strong influence of molecular ozone on degradation of ATZ and the partial involvement of hydroxyl radicals in the mechanism. Based on adsorption studies, atrazine has a low affinity towards adsorption on the surface of the catalysts. It is logical to assume that ozone reacts with the hydroxyl groups of the catalyst to form a highly reactive metal-ozone complex. This layer could react with a molecule of atrazine through an electron-transfer mechanism.
The residual concentration of ATZ and total organic carbon (TOC) were determined by High Performance Liquid Chromatography (HPLC) and Total Organic Carbon (TOC) analyses.
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LIN, HAO-WEI, and 林浩瑋. "Submerged flat ceramic membrane combined with ozone on removal of algae and decreased colloidal fouling in hybrid reactor." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5czr8b.
Full text
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Nkambule, Thabo Innocent. "An analytical approach to the characterization and removal of natural organic matter from water using ozone and cyclodextrin polyurethanes." Thesis, 2010. http://hdl.handle.net/10210/3171.
Full textAbstract:
M.Sc.The prevalence of natural organic matter (NOM) in water remains a huge challenge for water treatment companies and municipalities. NOM, however, is not a stand-alone problem as it affects water quality in many ways. NOM is largely responsible for the formation of disinfection by-products (DBPs) via its interaction with disinfectants during water disinfection. It is implicated for the undesirable colour, taste and odour of water and NOM even inhibits precipitation precursors which form the backbone of drinking water treatment. There is therefore no question that NOM, which is either a precursor to or direct cause of the problems highlighted above, should be considered as one of the critical design parameters to be considered for drinking water treatment. In our laboratories, research that involves the use of cyclodextrin (CD) polyurethanes for the removal of organic pollutants from water has been extensively investigated, and the CD polyurethanes have demonstrated the ability to effectively remove the organic species from water at low (ppb) concentrations. CDs, which are cyclic oligomers consisting of glucopyranosyl units linked together through α-1,4 glycosidic linkages, behave like molecular hosts. They are capable of forming inclusion complexes with guest molecules and hence can be utilised for the removal of organic contaminants from water. Their solubility in water, however, limits their application in the removal of organic contaminants from water. This limitation is easily resolved by polymerising the CDs into water-insoluble polymers with bifunctional linkers such as hexamethylene diisocyanate (HMDI). In this study, CD polyurethanes and ion exchange resins were used for the removal of NOM and possibly its DBPs from water. This study first investigated the local NOM source to establish its type and character, hence the study involved the characterization of the bulk water samples and fractionating the NOM using ion exchange resins for further characterization. The water samples were found to consist mainly of humic substances in the form of hydrophobic NOM, with the hydrophilic basic (HpiB) fraction being the most abundant NOM fraction in all samples. Trihalomethanes (THMs) were used as a representative of DBPs in this vii study. THMs formation studies of the individual NOM fractions indicated that all six NOM fractions were found to form THMs but in varying proportions. The HpiB fraction was found to be the most reactive precursor fraction for THMs formation. The ozonation process was also independently evaluated for its ability to remove the NOM fractions from water. Ozonation was found not to be very effective at NOM removal since it only resulted in a 12% overall decrease of the NOM in the water samples. The CD polyurethanes, when used alone, were also not very effective at removing the NOM fractions from water (maximum of 33% NOM removal). On the other hand, the combination method (i.e. the use of CD polyurethanes and ozonation for NOM removal) resulted in a good capability of the CD polyurethanes at decreasing some NOM fractions in water as evidenced by a 73% and 88% decrease of the HpiB and hydrophilic acid (HpiA) fractions, respectively. The 73% reduction of the HpiB fraction demonstrates a great success of the combination approach employed herein, as this study reports this fraction as the most reactive precursor fraction for THM formation.
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Halevy, Patrick. "Advanced Water Treatment Strategies for the Removal of Natural and Synthetic Organic Contaminants." Thesis, 2014. http://hdl.handle.net/10012/8225.
Full textAbstract:
Prior to full-scale implementation of process modifications at the Brantford WTP, a pilot-scale treatability study was conducted to investigate intermediate ozonation/AOP and to determine the most suitable granular media (anthracite, GAC, and Filtralite®) for deep-bed biological filtration. The primary objectives of this research were to provide insight into the destruction of natural and synthetic organics and assess ozonated and halogenated DBP formation.
Ozone alone was unable to achieve the 1-log removal target for geosmin or MCPA, unless disinfection-level dosages were applied. No improvement was observed when adding hydrogen peroxide.
A major obstacle to the implementation of ozonation in bromide-laden source waters is the formation of bromate. There is a direct correlation between ozone dose and bromate formation and by applying ozone dosages at disinfection levels, bromate is likely to exceed regulatory limits. However, adding hydrogen peroxide reduced the amount of bromate formed, and in most cases levels fell below regulatory limits. A linear correlation was established between bromate inhibition and increasing H2O2/O3 ratio at constant ozone dose.
Amongst the three filtration media investigated, only GAC achieved 1-log removal for geosmin and MCPA. The superiority of GAC over anthracite and Filtralite® was attributed to its adsorption affinity. Filtralite® and anthracite media were both ineffective for MCPA removal due to its non-biodegradable nature under conventional water treatment conditions.
At a 1 mg/L-ozone dose, GAC and Filtralite® filters achieved a 1-log geosmin removal. In contrast, a 1.44 mg/L ozone dose was required to meet this target with anthracite.
The tandem of ozone followed by biological filtration was very effective for the control of distribution system TTHM production regardless of filter media, with levels well below current and anticipated provincial regulatory limits.
The combination of intermediate ozonation followed by deep-bed biological filtration is well suited for treating Grand River water. Scale-up considerations include pairing the proper filter media to the size of the ozone generator. The best two treatment scenarios were: Option 1: select GAC media and size the ozone generator to produce a 1 mg/L dose. Option 2: select anthracite media and size the ozone generator to deliver a 2 mg/L dose.