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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Silver Nanoparticles: An effective antibacterial agent against Gram-negative bacteria

Wilcox, Ashley M. 19 December 2019 (has links)
No description available.
82

Future sludge management from a sustainability perspective / Framtida slamhantering från ett hållbarhetsperspektiv

Simensen, Ebba January 2023 (has links)
Syftet med projektet är att undersöka effekten av att leda över vattenverksslam från Norrvattens vattenverk, Görvälnverket, till Käppalaverkets reningsverk som ett steg i en mer hållbar slamhantering. Detta slamhanterings alternativ jämförs med en framtida lokal slamhantering vid Görvälnverket. Studien undersöker möjligheten att leda vattenverksslam över till Käppalaverket utifrån fyra huvudaspekter, vattenrening, drift, kostnad och miljöpåverkan. En litteraturstudie genomfördes med syfte att utvärdera hur vattenverksslammet kan påverka reningsprocesserna vid Käppalaverket. En Livscykelanalys genomfördes med syfte att utvärdera miljöpåverkan av att leda över vattenverksslam till Käppalaverket. Genomförbarheten utvärderades med hjälp av en multikriterieanalys, där tekniska, miljömässiga och ekonomiska aspekter utvärderades.  Resultat från studien visade att den framtida lokala slamhanteringen är mer fördelaktig från ett tekniskt och ekonomiskt perspektiv, än överledning av vattenverksslammet till Käppalaverket. En nackdel med överledning av vattenverksslam till Käppalaverket är att vattenverksslammet sannolikt kommer påverka avvattningen av avloppsslammet, vilket resulterar i en högre polymerförbrukning och en ökad hydraulisk belastning på centrifuger och rötkammare. Överledningen av vattenverksslam antas däremot inte ha en negativ påverka på kvaliteten av reningen vid Käppalaverket. Att leda vattenverksslam över till Käppalaverket ger en lägre miljöpåverkan med avseende på kemikalieutsläpp till vattenmiljön men en högre miljöpåverkan med avseende på transporter och energiförbrukning.  Överledning av vattenverksslam till Käppalaverket bedöms som genomförbart, men denna studie visar att den framtida lokala slamhanteringen på Görvälnverket är ett mer fördelaktigt alternativ. Om överledning av vattenverksslam till Käppalaverket fortsatt är ett aktuellt alternativ rekommenderas det att en mer djupgående studie utförs, där vattenverksslammet tillsätts till Käppalaverket för att utvärdera dess påverkan. / The aim with this project is to investigate the impact of leading the produced waterworks sludge (WWS) from Norrvattens drinking water treatment plant (DWTP), Görvälnverket, over to Käppalaverkets wastewater treatment plant (WWTP) as a step in a more sustainable sludge management. This alternative is compared to a future sludge management at Görvälnverket. The study, investigating the feasibility of leading the WWS over to Käppalaverket, is based on four main aspects, water treatment, operation, cost, and environmental impact. A literature study was performed to evaluate the effect of WWS on Käppalaverket. A life cycle assessment (LCA) analysis was performed to evaluate the environmental impact of leading the WWS over to Käppalaverket. The feasibility was evaluated using a multi-criteria decision analysis (MCDA), where technical, environmental, and economic aspects were considered. The study shows that the future sludge management is more favourable than leading the WWS over to Käppalaverket from a technical and economic aspect. The main drawback with leading the WWS over to Käppalaverket is that the WWS will likely impact the dewatering of the sewage sludge, resulting in a higher polymer consumption and an increased hydraulic load on centrifuges and digesters. However, the addition of WWS at Käppalaverket is not assumed to negatively impact the quality of the treatment at Käppalaverket. Leading the WWS over to Käppalaverket results in a lower environmental impact regarding chemical emissions but results in a higher environmental impact regarding transportation and energy consumption. Leading the WWS over to Käppalaverket was found to be feasible, although the future sludge management at Görvälnverket was found to be more favourably in this study. A more in depth study on the feasibility of leading the WWS over to Käppalaverkets is required to fully assess this aspect. A trial where the WWS is added to Käppalaverket is recommended to further evaluate the impact of the WWS.
83

Nitrogen Removal in Drinking Water Treatment - A Combination of Zeolite Sorption and the Anammox-Process

Eberle, Stephan Martin 28 July 2023 (has links)
Wasserknappheit und verminderte Wasserqualität sind Folgen des Klimawandels und zu-nehmender menschlichen Aktivitäten in der Landwirtschaft. Um den weltweiten Nahrungsmittelbedarf zu decken, ist der Einsatz von Stickstoffdüngern (hauptsächlich in Form von NH4+) notwendig, um die Qualität und den Ertrag von Nutzpflanzen zu steigern. Eine wachsende Weltbevölkerung macht einen verstärkten Einsatz von Stickstoffdüngern in der Landwirtschaft erforderlich, was zu einem erhöhten Eintrag von reaktivem Stickstoff in den Boden und das Grundwasser führt. Zusammen mit Abwassereinleitungen aus Haus-halten und Industrie in die Umwelt ist die Landwirtschaft Schätzungen zufolge der Hauptverschmutzer von Trinkwasserquellen. Neben Vermeidungs- und Verminderungsstrategien ist die Entwicklung innovativer Technologien zur Entfernung von Stickstoffverbindungen aus Trinkwasserquellen ein vielversprechender Ansatz zur Lösung dieses Problems. Diese Arbeit zeigt die Machbarkeit eines kombinierten Zeolith- und Anammox-Verfahrens zur Entfernung von Stickstoffverbindungen in einer grundwasserähnlichen Matrix für die Trinkwasseraufbereitung auf. Unter Verwendung von natürlichen Zeolithe (Klinoptilolith) als Sorbentien (für NH4+) und als Biofilmträger (für Anammox Bakterien) in einem Festbett-Biofilter wurde ein hocheffizienter, kostensparender, kompakter und wartungsarmer Prozess für dezentrale Anwendungen demonstriert. Darüber hinaus wurden in einer technischen und wirtschaftlichen Bewertung die Chancen und Risiken dieses Verfahrens für die Trinkwasseraufbereitung aufgezeigt. Der Einfluss von Schlüsselparametern auf die Sorption von NH4+ an natürlichen Zeolithe ergab eine hohe NH4+-Selektivität (NH4+ > K+ > Na+ > Mg2+ > Ca2+), hohe Sorptionskapazitäten (bis zu 21.3 mg(NH4+)/g) und hohe Entfernungsleistungen (bis zu 99 %). Untersuchungen in Multisorbat- und natürlichen Wassermatrices ergaben, dass die Konzentrationen von K+ und gelöstem organischem Kohlenstoff (DOC) den größten Einfluss auf die Sorption von NH4+ haben. Die Gleichgewichtsbeladung wurde dabei um bis zu 8% verringert. Der Einfluss von Anionen kann in Grundwasser typischen Konzentrationen bei pH-Werten oberhalb des pHPZC (Point of Zero Charge) vernachlässigt werden. Der pHPZC konnte zwischen pH 6.24 und pH 6.47 bestimmt werden. Zwischen pH 5 und pH 7 wurde eine maximale NH4+-Entfernungsleistung festgestellt, wohingegen aufgrund eines erhöhten Anteils an nicht sorbierbarem NH3(aq) ab pH ≥ 8 die Entfernungsleistung stark abnahm. Bei einer NH4+-Konzentration von 12.8 mg/L konnte der zugrundeliegende Sorptionsmechanismus auf den Ionenaustausch zurückgeführt werden (R² = 0,997). NH4+ beladene Zeolithe ließen sich am besten mit einer K+-Salzlösung regenerieren. Experimentell ermittelte Durchbruchskurven und eine zweifaktorielle Varianzanalyse bestätigten einen starken Einfluss der K+- und DOC-Konzentrationen auf den Durchbruch von NH4+ in natürlichen Wassermatrices. Bei einem Durchbruch von 50% wurde mit dem Einsatz von Elbewasser die Anzahl der behandelten Bettvolumina (BVs) um 69% reduziert. Darüber hinaus wurden die NH4+-Durchbruchskurven mit und ohne den Einfluss von K+ in Reinstwasser sowohl mit dem Linear Driving Force (LDF)- als auch mit dem Thomas-Modell erfolgreich modelliert und durch experimentelle Daten validiert. Die Verwendung solcher Modelle ist ein vielversprechendes Instrument, um zeitaufwändige und umfangreiche Untersuchungen im Labor und im Feld zu reduzieren. Um das Anammox-Verfahren erfolgreich etablieren zu können ist ein stabiler Betrieb der partiellen Nitritation (PN) zur Regulierung des erforderlichen stöchiometrischen NO2-/NH4+-Verhältnisses (1.32:1) entscheidend. Vorläufige Untersuchungen mit einem Fest-bett-Biofilter und einem Sequencing-Batch-Reaktor (SBR) zeigten, dass die folgenden Faktoren bei der Anwendung einer PN berücksichtigt werden müssen: (1) komplexe Wechselbeziehungen zwischen mikrobiellen Gemeinschaften mit unterschiedlichen Substratanforderungen, synergetische/kompetitive Wechselwirkungen, inhibierende Prozesse, und Stoffwechselprodukte; und (2) die Notwendigkeit, verschiedene Inhibierungsstrategien zu etablieren, um die Aktivität NO2- oxidierender Bakterien (NOB) zu unterdrücken. Es ist entscheidend, einen geschichteten und stabilen Biofilm zu etablieren, bevor eine PN unter Grundwasserbedingungen mit erhöhten Temperaturen und hohen NH4+-Konzentrationen eingesetzt wird. Das kombinierte Zeolith- und Anammox-Verfahren wurde in einem sequentiellen Zeolith-Anammox-Biofilter untersucht. Trotz weitaus niedrigerer Substratkonzentrationen und einer 8-fach höheren Filtergeschwindigkeit wurden vergleichbare Entfernungsleistungen für NH4+ (86%) und NO2- (76%) wie mit ähnlichen Zeolith- Anammox-Systemen für die Abwasseraufbereitung ermittelt. Die Entfernungsleistungen für NH4+ und NO2- konnten durch einen Vergleich ihrer Halbwertszeiten mit der effektiven hydraulischen Aufenthaltsdauer im Biofilter bestätigt werden. Die Entfernung von NH4+ erfolgte aufgrund der Sorption über Zeolithe und des Anammox-Stoffwechsel wesentlich schneller als für NO2-, deren Entfernung lediglich auf den Anammox-Stoffwechsel zurückführbar ist. Sowohl die ermittelten Halbwertszeiten als auch das von der Filterhöhe abhängige NO2-/NH4+-Verhältnis konnte eine schnellere NH4+-Entfernung bestätigen. Die Grenzwerte für NO2- der Weltgesundheitsorganisation (WHO: 3 mg/L) und der Vereinigten Staaten von Amerika (USA: 3.2 mg/L)) wurden bei Filtergeschwindigkeiten von 0.032 m/h und 0.043 m/h eingehalten. Bei 0.032 m/h und 0.043 m/h wurden die NH4+-Grenzwerte für China (0.6 mg/L) und Deutschland (0.5 mg/L) leicht überschritten. Durch eine Korrelation der NH4+- und NO2--Entfernung mit der elektrischen Leitfähigkeit konnte darüber hinaus bei allen untersuchten Filtergeschwindigkeiten ein vereinfachtes Verfahren zur Prozessüberwachung demonstriert werden. Eine technisch-wirtschaftliche Bewertung ergab die höchste technische Wertigkeit (X) für das Ionenaustauschverfahren mit Zeolithe (X: 0.79), gefolgt vom Nitrifikationsverfahren (X: 0.68) und dem Verfahren der partiellen Nitritation/Anammox (PN/A) (X: 0.52). Das Ionen-austauschverfahren zeichnet sich dabei vor allem durch eine einfache Handhabung und Anpassung hinsichtlich schwankender NH4+-Konzentrationen im Zulauf sowie eine hohe Betriebssicherheit aus. Dagegen sind vergleichsweise lange Etablierungszeiten, eine un-sichere Betriebssicherheit und eine hohe verfahrenstechnische Komplexität für das PN/A-Verfahren zu erwarten. Die Gesamtkosten jedes Verfahrens wurden unter Berücksichtigung der Anlagengröße, lokaler Strompreise und unterschiedlicher NH4+-Konzentrationen im Zulauf über einen Zeitraum von 20 Jahren berechnet. Auf Grundlage dieser Berechnung können die folgenden Empfehlungen für eine dezentrale Trinkwasseraufbereitung ausgesprochen werden: (1) Das Ionenaustauschverfahren kann für NH4+-Konzentrationen bis zu 21 mg/L empfohlen werden; (2) das PN/A-Verfahren wird bei höheren NH4+-Konzentrationen wirtschaftlicher; und (3) das Nitrifikationsverfahren weist ab einer NH4+-Konzentration von ≥ 14 mg/L im Zulauf eine ungünstige Wirtschaftlichkeit auf, da eine zusätzliche Denitrifikationsstufe eingeplant werden muss um den NO3- Grenzwert von 50 mg/L der WHO und von Deutschland einzuhalten. Werden die Berechnungen mit einem niedrigeren KCl-Preis wiederholt, kann das Ionenaustauschverfahren bis zu einer NH4+-Konzentration von 60 mg/L empfohlen werden. Das PN/A-Verfahren stellt bei NH4+-Konzentrationen ≥ 60 mg/L das wirtschaftlichere Verfahren dar. Insgesamt ist das kombinierte Zeolith- und Anammox-Verfahren ein vielversprechendes Verfahren zur Entfernung von Stickstoffverbindungen in dezentralen Anwendungen für die Trinkwasseraufbereitung in Schwellen- und Entwicklungsländern des globalen Südens. Insbesondere dort, wo erhöhte Temperaturen und hohe NH4+-Konzentrationen in Trinkwasserquellen zu finden sind.:1. Introduction ................................................................................................................. 1 2. Topic and Objective of the Thesis ............................................................................. 3 3. Background and Literature Review ........................................................................... 5 3.1 General Aspects about the Global Nitrogen Cycle ............................................ 5 3.1.1 Nitrogen Reservoirs and Anthropogenic Activities ........................................... 5 3.1.2 Nitrogen Cycle in Riverbank Filtration and Groundwater ................................. 7 3.1.3 Ecological Relevance and Physiological Effects of Nitrogen Compounds ..... 10 3.2 Ammonium Removal Processes – Current State of Knowledge .................... 12 3.2.1 Distinction: Drinking Water vs. Wastewater Treatment .................................. 13 3.2.2 Zeolites: Occurrence, Characteristics and Application ................................... 17 3.2.3 Partial Nitritation and Anammox ..................................................................... 20 4. Results and Discussion ............................................................................................ 25 4.1 Publication 1: Granular Natural Zeolites: Cost-Effective Adsorbents for the Removal of Ammonium from Drinking Water ............................................................ 25 4.2 Publication 2: Natural Zeolites for the Sorption of Ammonium: Breakthrough Curve Evaluation and Modeling .................................................................................. 48 4.3 Preliminary Investigations to the Partial Nitritation ........................................ 66 4.3.1 Material and Methods .................................................................................... 66 4.3.2 Results and Discussion .................................................................................. 70 4.3.3 Conclusions ................................................................................................... 77 4.4 Publication 3: A Sequential Anammox Zeolite-Biofilter for the Removal of Nitrogen Compounds from Drinking Water ............................................................... 79 4.5 Technical-Economic Evaluation ........................................................................ 99 4.5.1 Material and Methods .................................................................................... 99 4.5.2 Results and Discussion ................................................................................ 103 4.5.3 Conclusions ................................................................................................. 114 5. Summary and General Conclusions ...................................................................... 116 6. Outlook ..................................................................................................................... 119 References ..................................................................................................................... 122 List of Tables ................................................................................................................. 139 List of Figures ................................................................................................................ 141 List of Abbreviations ..................................................................................................... 144 List of Formular ............................................................................................................. 146 Appendix ........................................................................................................................ 147 A-1 Supporting Information: Section 3 .................................................................. 147 A-2 Supporting Information: Section 4 .................................................................. 149 A-2.1 Publication 1: Granular Natural Zeolite: Cost-Effective Adsorbents for the Removal of Ammonium from Drinking Water ............................................................ 149 A-2.2 Publication 2: Natural Zeolites for the Sorption of Ammonium: Breakthrough Evaluation and its Modeling ...................................................................................... 157 A-2.3 Preliminary Investigations to Partial Nitritation ............................................. 162 A-2.4 Publication 3: A Sequential Anammox Zeolite-Biofilter for the Removal of Nitrogen Compounds from Drinking Water ............................................................... 168 A-2.5 Technical-Economic Evaluation ................................................................... 179 Journal Articles and Conference Contributions ......................................................... 200 Acknowledgements ....................................................................................................... 201 Declaration ..................................................................................................................... 202
84

Ozone And Gac Treatment Of A Central Florida Groundwater For Sulfide And Disinfectant By-product Control

Lamoureux, Tara 01 January 2013 (has links)
This study evaluated the combination of ozone and granular activated carbon (GAC) treatment for the removal of sulfide and disinfection byproduct (DBP) precursors in drinking water at the pilot-scale. The research conducted was performed at the Auxiliary (Aux) and Main Water Treatment Plants (WTPs) in Sanford, Florida. Both WTPs rely upon groundwater sources that contain total sulfide ranging from 0.02 to 2.35 mg/L and total organic carbon (TOC) ranging from 0.61 to 2.20 mg/L. The Aux WTP’s raw water contains, on average, 88% more sulfide and 24% more TOC than the Main WTP. Haloacetic acids (HAA5) and total trihalomethanes (TTHMs) comprise the regulated forms of DBPs. HAA5 are consistently below the maximum contaminant level (MCL) of 60 μg/L, while TTHM ranges from 70 to 110 μg/L, at times exceeding the MCL of 80 μg/L in the distribution system. Ozone alone removed total sulfide and reduced UV-254 by about 60% at the Aux Plant and 35% at the Main Plant. Producing an ozone residual of 0.50 mg/L prevented the formation of bromate while removing approximately 35 to 60% concentration of DBP precursors as measured by UV-254. Operating the GAC unit at an empty bed contact time (EBCT) of 10 minutes for the Aux Plant and 5.5 minutes for the Main Plant resulted in 75% and 53% of UV-254 reduction, respectively. The average 120 hour TTHM formation potential for the Aux and Main Plants were 66 μg/L and 52 μg/L, respectively, after treatment by ozone and GAC. GAC exhaustion was deemed to have occurred after seven weeks for the Aux Plant and eleven weeks for the Main Plant. The GAC columns operated in three phases: an adsorption phase, a transitional phase, and a biologically activated carbon (BAC) phase. The GAC adsorption phase was found to produce the lowest TTHMs; however, TTHMs remained less than 80 μg/L during the BAC stage at each plant. BAC exhaustion did not occur iv during the course of this study. Ozone-GAC reduced chlorine demand by 73% for the Aux Plant and 10% for the Main Plant.
85

Tracking Cyanobacteria Cell Integrity through Chemical and Mechanical Stressors in the Water Treatment Process

Elliott, Dane 30 September 2022 (has links)
No description available.
86

Application of indigenous materials in drinking water treatment

Kalibbala, Herbert Mpagi January 2007 (has links)
Volcanic ash and Moringa oleifera (M. oleifera) were investigated as indigenous materials for drinking water treatment based on problems identified at Kampala and Masaka water treatment plants in Uganda. Coagulation experiments were done using swamp raw water at Masaka National Water &amp; Sewerage Corporation water treatment plant and pilot-scale filtration experiments carried out at Ggaba II (Kampala) water treatment plant. The results from the study indicated that there were both operational and design handicaps at the treatment plants in Kampala. There is need to modify the filtration and clarification units to enable production of water meeting both the national and international standards. At Masaka water treatment, there was increase in trihalomethanes concentration as a result of pre-chlorination. Following aeration and pre-chlorination processes, the average increase of total trihalomethanes concentration was over 4000% with over 99% being chloroform. Preliminary results from the jar test experiments indicated that use of alum with MOCSC as coagulant aid is promising as a first stage in the treatment train for waters with a humic materials and high content of iron, typical of swamp water sources. This would probably eliminate the formation of unwanted by-products by eliminating the pre-chlorination process. Assessment of the characteristics of the volcanic ash showed that it meets the requirements for a filtration material; and results obtained from the pilot study showed that it was a suitable alternative material for use in a dual media filtration system. There was an increase in the filter run length of about two and half fold in the dual media filtration column compared to the mono medium column. Both columns produced similar water quality levels. Therefore, conversion of the rapid sand filters at Ggaba and similar water treatment plants in the country to dual media (volcanic ash on top of sand) systems would probably significantly improve the performance of the filtration systems. / <p>Obs! ISBN: 978-91-7283-565-76</p><p>QC 20101110</p>
87

Development of a small scale water treatment system for fluoride removal for rural areas

Dlamini, Thulani January 2015 (has links)
Submitted in fulfillment of the requirements for the degree of Master of Engineering in Chemical Engineering, Durban University of Technology. Durban. South Africa, 2015. / Several areas in the world such as the United States of America, Sri Lanka, China, Argentina, Canada, Tanzania, Kenya, South Africa and many others have a problem of high fluoride content in drinking water. Generally fluoride levels above 1.5 ppm in water may result in dental and skeletal fluorosis in humans depending on quantity consumed (Fan et al., 2003; Meenakshi, 2004). Remote rural areas where there are no water treatment facilities are more vulnerable to this problem. Adsorbents such as activated alumina and FR-10 resin seem to have a potential for successful application in rural areas. These methods however require pre-treatment if the feed has high turbidity. A membrane based system called woven fabric microfiltration gravity filter (WFMFGF) developed by Durban University of Technology proved to be suitable for turbidity removal. The main objective of this research was to develop a small water treatment system for fluoride removal. The small water treatment system developed in this study consists of WFMFGF for pre-treatment and an adsorption column. The WFMFGF is made up of a 40 L container packed with 15 immersed flat sheet membrane elements. The operation of the WFMFGF is in batch mode, driven by varying static head. The static head variation results in flow rate variation through the system. This in turn result in variation of contact time, velocity as well as pressure drop in the fluoride removal unit. Specific objectives of the study were: (1) to establish the maximum and minimum flow rates through the WFMFGF system, the total run time before cleaning is required and the best cleaning method for this particular membrane system. (2) to evaluate and compare the performance of activated alumina and FR-10 resin on varying contact time, velocity and pressure drop on the fluoride removal unit. The adsorbents were also compared on adsorption capacity, cost and ease of operation. The minimum and maximum flow rates through the WFMFGF were found to be 5 l/hr and 100 l/hr respectively. It was found that the system can be run for more than a month before requiring cleaning. The suitable cleaning method was found to be soaking the membranes in 0.0225 percent sodium hypochlorite solution overnight and brushing them using a plastic brush. The comparison of the performance of FR-10 resin to activated alumina found that the adsorbents gave equal performance based on the given criteria. FR-10 resin had higher adsorption capacity, gave good quality treated water even with shorter contact time and operated at wider velocity range. Activated alumina on the other hand had an advantage of lower costs, lower pressure drop and ease of use. According to Pontius (1990), the performance of activated alumina can be improved by intermittent operation. Point of use (POU) systems are generally operated intermittently. This improves the fluoride removal efficiency of activated alumina giving it more advantage over FR-10 resin. Based on this activated alumina was selected as the best adsorbent for the system. After the adsorbent was selected, the adsorption column was designed. The column operation regime was 3.5 minutes minimum contact time and 1.17 to 7.8 m/hr velocity range. The activated alumina adsorption capacity was 1.53mg/g. The column had an inside diameter of 70 mm. It was packed with activated alumina to a bed height of 400 mm. The column inlet and outlet pipes were made of PVC with a standard pipe size of 20 mm outside diameter. A valve at the column inlet pipe allowed water to flow through the system.
88

Remoção de substâncias húmicas na dupla filtração com filtro ascendente de pedregulho / Removal of humic substances in double filtration system using an upflow gravel filter

Benini, Bianca Dieile da Silva 25 April 2003 (has links)
Este trabalho foi realizado com o objetivo de avaliar o comportamento de um sistema de dupla filtração, utilizando filtro ascendente de pedregulho seguido de filtro rápido descendente na remoção de substâncias húmicas. A parte experimental foi realizada em uma instalação piloto, que utilizou como afluente a água do Ribeirão Feijão na qual foi adicionado extrato de substâncias húmicas, previamente extraído de solo turfoso por meio de extração alcalina, para que a cor verdadeira da água de estudo resultasse entre 90 e 110 uH. As condições de coagulação, como gradiente de velocidade, dosagem e pH, foram definidos em ensaios com jarteste. As taxas utilizadas no filtro ascendente em pedregulho foram de 80 e 120 m3/m2.dia e no sistema de filtração rápida descendente de 80, 120, 150, 180, 220 e 240 m3/m2.dia. As carreiras tiveram duração máxima de 72 horas. A utilização do critério de realização de Descargas de Fundos Intermediárias (DFIs), quando o efluente do Filtro Ascendente de Pedregulho (FAP) atingisse valor maior ou igual 50 uH, não permitiu aumento da cor no efluente final. O sistema de dupla filtração estudado foi eficiente na remoção de cor, atingindo diversas vezes remoção completa; outros parâmetros relativos à concentração de substâncias húmicas, como absorvância (254 nm) e Carbono Orgânico Dissolvido (COD), foram removidos entre 89,1 a 93,6% e 27,5 a 48,5% respectivamente. / The present work was carried out to evaluate the removal of humic substances in a double filtration system, comprising on upflow gravel prefilter followed by a rapid down flow filter. Raw water was abstracted from the influent took to the municipal water treatment Plant 2. Humic substances were extracted from peat through alkaline process. The concentrated solution was pumped to raw water in order to obtain true colour of 90-110 Hu in the influent to the pilot plant. Filtration rates studied were as follows: 80 and 120 m3/m2.day in the upflow filter 80, 120, 150, 180, 220 e 240 m3/m2.day in the down flow filter. Maximum filter run length was fixed in 72 hours. Intermediate down flushes in the upflow filter were performed during the run when the effluent colour reached 50 Hu. It is concluded that the system performed efficiently to remove colour; in most part of the effluent colour remained bellow 1 Hu. Absorbance (254 nm) removal resulted high (between 89,1% and 93,6%). Dissolved organic carbon resulted satisfactory (27,5% to 48,5%).
89

Remoção de Giardia spp. e Cryptosporidium spp. em águas de abastecimento com turbidez elevada utilizando cloreto de polialumínio: estudo em escala de bancada e desafios analíticos / Giardia spp. Cysts and Cryptosporidium spp. Oocysts removal in high turbid drinking water using polyaluminum chloride: a bench scale study and analytical challenges

Maciel, Paulo Marcos Faria 22 August 2014 (has links)
O objetivo deste trabalho foi avaliar o desempenho da remoção de cistos deGiardia spp. e oocistos de Cryptosporidium parvum, em águas de abastecimento com turbidez elevada, em experimentos em escala de bancada (coagulação, floculação, decantação e filtração). Para tanto, empregou-se o coagulante cloreto de polialumínio &#8211; PAC. O método de filtração em membranas foi adotado para a concentração de protozoários, seguido ou não da etapa de purificação por separação imunomagnética &#8211; IMS. Os métodos foram avaliados em experimentos de controle de qualidade analítica e o método sem IMS apresentou as seguintes porcentagens de recuperação, 80% ±16,32% para cistos de Giardia spp. e 5% ±10,00% para oocistos de C. parvum. O método com IMS apresentou 31,5%±7,55% de recuperação para cistos de Giardia spp. e 5,75%±3,20% de recuperação para oocistos de C. parvum. Os experimentos demonstraram que não houve melhora na remoção de ambos os protozoários na condição de maior dosagem de coagulante (65 mg.L-1 de PAC e pH 7,29). A condição de menor dosagem de coagulante (25 mg.L-1 de PAC e pH 6,76) apresentou um desempenho melhor, ao contrário de uma expectativa de que a maior dosagem de coagulante pudesse favorecer a remoção destes microrganismos. A condição de menor dosagem apresentou, na água filtrada, 50 e 75% de ausência de identificação de cistos de Giardia e oocistos de C. parvum, respectivamente. A condição de maior dosagem apresentou (oo)cistos na água filtrada de todas amostras analisadas. Estes resultados indicam a importância do controle da coagulação na remoção de protozoários. / The aim of this study was to evaluate the performance of Giardia spp. cysts and Cryptosporidium parvum oocysts removal in a bench scale experiment. The coagulant polyaluminium chloride &#8211; PACl was used in this research. The protozoa concentration tests were performed by applying the Membrane Filtration method, with and without Immunomagnetic Separation assay-IMS. The methods were evaluated using control experiments and the method without IMS had the following percentage recovery, 80% ± 16.32% and 5% ±10.00% for Giardia cysts and C. parvum oocysts, respectively. The method with IMS presented 31.5% ± 7.55% and 5.75% ± 3.20% of percentage recovery for Giardia cysts and C. parvum oocysts, respectively. Bench scale experimental results have clearly shown that there was no improvement in protozoa removal using the superior dosage of coagulant. The inferior dosage condition (25 mg.L-1 of PACl and pH 6,76) performed better, which was contrary to what was expected in which a superior dosage of coagulant could favour when removing microorganisms. The inferior dosage condition presented 50% and 75% of absence of Giardia cysts and C. parvum oocysts in the final water, respectively. The second coagulation condition (65 mg.L-1 of PACl and pH 7,29) presented protozoa (oo)cysts in the final water of all the samples examined. These results indicate the importance of coagulation control in protozoa removal.
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Development of an integrated tool for Process Modelling and Life Cycle Assessment : Ecodesign of process plants and application to drinking water treatment / Développement d’un outil intégré pour la Modélisation de Procédés et l’Analyse de Cycle de Vie : Ecoconception d’usines de procédés et application à la production d’eau potable

Mery, Yoann 14 December 2012 (has links)
Des outils adaptés pour s’attaquer aux problématiques environnementales sont nécessaires mais malheureusement absents de l’industrie. En effet, l’introduction de nouvelles pratiques d’écoconception dans l’industrie des procédés est entravée par le manque de réalisme et de flexibilité des outils associés. Les objectifs principaux de ce travail de recherche étaient le développement d’un outil intégré pour la modélisation de procédés et l’analyse de cycle de vie (PM-LCA), ainsi que la formulation d’une approche méthodologique affiliée pour l’écoconception de procédés. L’outil logiciel et l’approche méthodologique sont appliqués à la production d’eau potable.La revue de la littérature scientifique a permis d’appréhender les efforts de recherche nécessaires. Les principales lignes directrices sont établies en conséquence.L’outil développé, nommé EVALEAU, consiste en une bibliothèque logicielle de modèles de procédés unitaires permettant le calcul d’inventaire de données en fonction de paramètres de procédés. L’outil est embarqué dans le logiciel ACV Umberto® en complément de la base de données Ecoinvent. Uneboîte à outils pour l’analyse de sensibilité, basée sur la méthode de Morris, est implémentée pour l’identification des paramètres de procédés ayant une influence majeure sur les résultats d’impacts environnementaux.L’outil EVALEAU est testé sur deux études de cas - deux usines de production d’eau potable existantes. La fiabilité de l’approche est démontrée à travers la comparaison des calculs de qualité de l’eau, de consommations d’énergie et de matériaux avec les données réelles recueillies sur site. Une procédure d’écoconception est expérimentée sur une chaîne de traitement complexe démontrant ainsi la pertinence des résultats de simulations et l’utilité de l’analyse de sensibilité pour un choix optimal des paramètres opératoires. En conséquence, ce premier outil PM-LCA est censé promouvoir l’introduction de pratiques d’écoconception dans l’industrie de l’eau / Adapted tools for tackling environmental issues are necessary but they are still missing in industry. Indeed, the introduction of ecodesign practices in the process industry is hindered by the lack of realism and flexibility of related tools.The main objectives of this research work were the development of a fully integrated tool for Process Modelling & Life Cycle Assessment (PM-LCA), and the formulation of an affiliated methodological approach for process ecodesign. The software tool and the methodological approach are meant to be applied to water treatment technologies.The literature review leads to a better comprehension of the required research efforts. The main guidelines for the development of the software tool are stated accordingly.The developed tool, named EVALEAU, consists in a library of unit process models allowing life cycleinventory calculation in function of process parameters. The tool is embedded in Umberto® LCA software and is complementary to Ecoinvent database. A sensitivity analysis toolbox, based on theMorris method, was included for the identification of the process parameters mainly affecting the lifecycle impact assessment results.EVALEAU tool was tested through two case studies - two existing drinking water plants. There liability of the modelling approach was demonstrated through water quality simulation, energy and materials inventory simulation, compared with site real data. An ecodesign procedure was experienced on a complex water treatment chain, demonstrating the relevance of simulation results and the usefulness of sensitivity analysis for an optimal choice of operation parameters.This first developed PM-LCA tool is dedicated to foster the introduction of ecodesign practices in the water industry

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