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1
Belhadj, Mohamed. "Vers une modélisation mathématique de la filtration des globules blancs du sang." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00011977.
Abstract:
Cette thèse concerne l'étude de modèles mathématiques et méthodes numériques motivés par la filtration des globules blancs du sang. Dans la première partie, nous définissons des modèles mathématiques qui réprésentent les principaux phénomènes physiques qui entrent en jeu dans le procédé de la filtration.
La deuxième partie est dédiée à l'analyse mathématique de systèmes d'équations aux dérivées partielles modélisant le procédé de la filtration. Tout d'abord, nous considérons un système d'équations semi-linéaires de type hyperbolique-parabolique avec une diffusion anisotrope dégénérée. Nous étudions ce problème avec une théorie $L^{1}$; nous considérons en particulier l'existence et l'unicité de solutions faibles ainsi que d'autres propriétés comme le principe du maximum; puis nous établissons la limite quand la constante de réaction devient grande. Nous montrons que le système converge vers une équation non linéaire parabolique-hyperbolique qui généralise le problème de Stefan. Nous étudions également, par des techniques de l'homogénéisation, la filtration au travers de milieux poreux fibrés. Le réseau des fibres étudié est celui utilisé par M. Briane dans le cadre d'une étude sur la conduction thermique des tissus biologiques. Nous dérivons et justifions l'équation de Darcy ainsi que la forme du tenseur de perméabilité pour un tel milieu fibreux. Les résultats théoriques concernant la perméabilité sont illustrés par quelques simulations numériques. Finalement, nous considérons le cas où le diamètre des fibres tend vers zéro. En appliquant des résultats de G. Allaire à notre cas, nous justifions rigoureusement la forme du terme dominant dans les formules de perméabilité efficace utilisées en ingénierie. Ces résultats sont également confirmés par un calcul numérique direct de la perméabilité, dans lequel la petitesse du diamètre des fibres rend nécessaire le recours à des approximations de précision élevée.
La définition des méthodes numériques efficaces pour approximer la solution des modèles mathématiques est envisagée dans la troisième partie. Précisément, concernant les équations de Darcy, nous avons utilisé la méthode des éléments finis mixtes hybrides. Pour la résolution de l'équation du transport, nous avons implémenté une méthode numérique utilisant des volumes finis pour la discrétisation du terme convection/réaction associé à une approximation mixte hybride pour la discrétisation du terme dispersif.
2
Barbe, Laurent. "Mécanismes d'adhérence des leucocytes aux fibres synthétiques : application à la filtration du sang." Paris 7, 2001. https://tel.archives-ouvertes.fr/tel-00002228.
3
GUIMBRETIERE, JEAN-FRANCOIS. "Etude hemorheologique clinique de 65 syndromes inflammatoires explores par bilan biologique standard et test de filtration de sang total." Nantes, 1989. http://www.theses.fr/1989NANT080M.
4
Philp, Jane. "Etude de l'hémolyse et de l'absorption des protéines plasmatiques en plasmaphérèse membranaire à débit constant et pulsé." Compiègne, 1993. http://www.theses.fr/1993COMPD658.
Abstract:
Cette thèse est consacrée à l'étude des problèmes posés par la plasmaphérèse membranaire et plus spécialement ceux de l'hémolyse et du colmatage de la membrane. Un des objectifs était de déterminer les causes de l'hémolyse lors de la filtration et dans quelle mesure la conception du module peut affecter le degré d'hémolyse produite. Cette thèse a montré que l'on pouvait réduire l'hémolyse en réduisant la longueur du filtre car cela réduit à la fois la pression transmembranaire et le temps de résidence du sang près de la membrane. L'adsorption des protéines par la membrane a été également étudiée. On trouve que cette adsorption est importante mais qu'elle peut être réduite en alimentant le filtre par un débit pulsé. La filtration extra liminale de l'extérieur vers l'intérieur des fibres a été également étudiée sur des prototypes spéciaux à peau externe. Dans le cas de la plasmaphérèse, ce procédé est moins intéressant car il réduit le flux de filtration et augmente l'hémolyse. Enfin, l'adaptation de notre système de filtration par débit pulsé à un moniteur de plasmaphérèse comportant une pompe sur le circuit de perméat a été réalisée et testée in vitro avec du sang bovinThis thesis has focused on the problems encountered during membrane plasmapheresis. These are specifically the causes of haemolysis and flux decline during membrane separations. The objective was to find what causes haemolysis in a filtering system and how the design of a module may affect the overall haemolysis. This thesis shows that haemolysis is due to the pressure gradient across the membrane and that by reducing fibber length the potential for haemolysis is reduced. The adsorption of plasma proteins onto the membrane surface was also investigated. It was shown that during steady blood flow conditions high levels of adsorption or trapping occurred and by introducing flow pulsations this level maybe minimised. A comparison between blood flow inside and outside the fibbers was made with respect to both filtration and haemolysis performances. It was found that with blood flow inside the fibbers haemolysis was lowest and filtration was highest. Having considered these factors a system of control was tested in vitro using bovine blood and flow pulsations. The system yielded a high filtration with very low haemolysis levels
5
Pellet, Charlotte. "Nouvelles fonctionnalités de copolymères en brosse dans les suspensions minérales concentrées." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066699/document.
Abstract:
La thèse porte sur une nouvelle classe de polymères à architecture en brosse, synthétisés à l'échelle industrielle et utilisés comme additifs dans les suspensions colloïdales pour le couchage du papier. Le polymère en brosse contrôle la déshydratation et le séchage des suspensions ce qui permet d'obtenir des revêtements d'une qualité incomparable. L'objectif est de modéliser sur un plan fondamental le rôle fonctionnel des polymères en relation avec les performances en application. Dans une première partie nous étudions leurs propriétés physicochimiques, structurales et rhéologiques en solution en discutant les spécificités dues à l'architecture en brosse. Dans une seconde partie nous analysons à l'aide d'un dispositif expérimental original les propriétés de rétention d'eau apportées par les polymères. Dans une troisième partie nous étudions le séchage de suspensions de carbonate de calcium sur des substrats solides, qui conduit en général à des motifs hétérogènes dits en " anneau de café ". Nous avons découvert que les polymères en brosse à très faible concentration suppriment ces défauts de séchage de façon remarquable. Le nouveau mécanisme physique à l'¿uvre, que nous appelons effet Marangoni auto-induit, résulte des propriétés interfaciales des polymères et de leurs interactions spécifiques avec les particules de carbonate de calcium. Pour conclure nous établissons un lien entre les propriétés de rétention d'eau et l'inhibition des défauts de séchage. Nous démontrons alors le caractère générique de nos résultats en les transposant à une suspension biologique, le sang, où les polymères pourraient présenter un intérêt dans le traitement de pathologies cardiovasculairesThis work focuses on a new class of bottlebrush polymers, synthesized on an industrial scale and used as additives in colloidal suspensions for paper coatings. The bottlebrush polymer controls the dehydration and drying of the suspensions, and leads to coatings of outstanding quality. Our aim is to model the functional role of these polymers from a fundamental perspective in relation with applicative performances. In a first part we study their physicochemical, structural and rheological properties in solution, emphasizing the specificities due to the brush architecture. In a second part we implement an original experimental setup to analyze the water retention properties brought by the polymers. In a third part we study the drying of calcium carbonate suspensions on solid substrates, which in general forms to heterogeneous patterns called “coffee-rings”. We discovered that at very low concentration, bottlebrush polymers remarkably suppress these defects. We call auto-induced Marangoni effect the new physical mechanism at work. It results from the interfacial properties of the polymers and their specific interactions with calcium carbonate particles. To conclude, we establish a link between water retention properties and drying defect inhibition. We demonstrate the generic character of our results which can be transposed to a biological suspension, blood, where these polymers could be of interest for cardiovascular disease treatment
6
Sagot, Matthieu. "Détection électrique In-Situ des événements de microfiltration dans des milieux complexes." Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSEP028.
Abstract:
La microfiltration constitue un domaine scientifique et technologique bien documenté, mais qui nécessite encore des recherches approfondies lorsqu'il s'agit de cibler la filtration spécifique et précise d'éléments rares au sein d'un milieu complexe. En effet, des solutions innovantes pour le filtrage d'échantillons dans des milieux complexes pourraient être la clé de multiples problématiques liées à la santé et à l'environnement. Le sang est un exemple concret de milieu complexe : il contient une quantité importante et variée de cellules et de protéines, présentant une viscosité trois à huit fois supérieure à celle de l'eau, ainsi qu'un comportement non newtonien en écoulement. Les applications cliniques de la filtration sanguine nécessitent le traitement de grands volumes de sang, soit en raison de la rareté des éléments ciblés (dans le cas de la capture des cellules tumorales circulantes, la pertinence clinique commence à 5 CTC/mL de sang), soit parce que l'ensemble du sang circulant doit être purgé d'entités indésirables (telles que des agrégats cellulaires ou des microparticules circulantes dans les maladies cardiovasculaires et les accidents vasculaires cérébraux). Enfin, la nature biologique des éléments ciblés peut introduire une variabilité dans leur taille et leur forme, posant ainsi des défis fluidiques pour leur récupération au sein de tels milieux.La filtration sanguine est un processus central dans l'hémodialyse, la surveillance des maladies cardiovasculaires et les applications de biopsie liquide basées sur la capture sélective des cellules tumorales circulantes (CTC), entre autres contextes cliniques. Pour de telles applications, la micro et nano fabrication utilisant des méthodes et des techniques de précision de l'industrie des semi-conducteurs offre la possibilité de contrôler avec une grande précision la taille des pores de filtration par rapport à la taille des éléments ciblés nécessitant une filtration. Ce niveau de précision dans le processus de fabrication ouvre la voie à la rétention exclusive de l'élément ciblé, conduisant à l'information biologique dans le cas d'une application diagnostique, ou à la pathogénicité dans le cas d'applications thérapeutiques, sans altérer la composition du sang élué. Cependant, en raison du traitement d'un grand volume de sang et de la présence de millions de globules blancs et de milliards de globules rouges par millilitre de sang, de tels filtres microfabriqués sont sujets à l'obstruction due à l'accumulation de matériau retenue au fil du temps. Ce désavantage incite au développement d'une méthode in-situ capable de détecter la densité cellulaire à la surface de ces filtres pendant leur utilisation, afin de surveiller leur saturation en vue de nettoyer leur surface ou de procéder à leur remplacement par d’autres filtres. Dans ce contexte, nous proposons des dispositifs microfabriqués en salle blanche capables de répondre à ces exigences. Les dispositifs de détection produits combinent une membrane de filtration avec une méthode de détection cellulaire électrique in-situ à travers des microélectrodes interdigités et des mesures de spectroscopie d'impédance. Malgré l'utilisation de pores de filtration à l'échelle du micron et de dispositifs microfabriqués, nous proposons un design spécifique permettant la filtration sanguine à un débit élevé (11,5 mL/min), bien supérieur à celui des dispositifs microfluidique habituels. Enfin, nous démontrons que des mesures électriques stables peuvent être réalisées dans du sang entier à des débits élevés pour surveiller la saturation du filtre par les cellules retenues. De plus, l'analyse fine des cellules capturées, habituellement confiée à des laboratoires externes, pourrait être transférée au chevet du patient tout au long du traitement des échantillons, si une analyse in-situ et une phénotypisation en temps réel des cellules collectées par leur signature électrique pouvaient être démontréesMicrofiltration is a well-documented scientific and technological domain that still requires research when targeting the specific and accurate filtration of rare elements inside a complex medium. Indeed, innovative solutions for sample filtering of complex media may hold the key to multiple health-related and environmental issues and applications. Blood is a good example of a complex medium: it contains a large quantity and variety of cells and proteins and exhibits a viscosity three to eight times greater than water and non-Newtonian behavior when flowing. Clinical applications of blood filtration require processing large volume of blood either because of the scarcity of the targeted elements (in the case of circulating tumor cell capture, clinical relevance starts at 5 CTCs/mL of blood) or because the whole circulating blood needs to be expurgated from some adverse entities (such as cell aggregates or circulating microparticles in stroke and cardiovascular diseases). Finally, the biological nature of the targeted elements may introduce variability in the targeted element size and shape, therefore bringing fluidic challenges for their retrieval within such media. Blood filtration is a process which is central in hemodialysis, cardiovascular disease monitoring, and liquid biopsy applications based on the selective capture of Circulating Tumor Cells (CTCs), among other clinical contexts. For such applications, micro and nanofabrication using methods and techniques used today in advanced semi-conductor industry, brings the ability to control with great accuracy the size of the filtering pores with respect to the size of the targeted elements that require filtration. This level of accuracy in the fabrication process opens the opportunity to retain only the targeted element driving the biological information in the case of a diagnosis application or driving the pathogenicity in the case of therapeutic applications without impairing the composition of the eluted blood. However, because a large volume of blood is processed and due to the presence of millions of white blood cells (WBC) and billions of red blood cells (RBC) per milliliter of blood, such advanced microfabricated filters are subjected to clogging due to the unwanted accumulation of material unavoidably retained among time. This drawback appeals to the development of an in-situ method capable of sensing the cell density at the surface of these filters during use, to monitor their saturation in order to clean their surface or to proceed to their replacement by fresh ones. In this context, we propose clean room microfabricated devices capable of fulfilling these requirements. The produced sensing devices combine a filtering membrane with an in situ cellular electrical detection method through interdigitated microelectrodes and impedance spectroscopy measurements. Despite using micron-scale filtering pores and microfabricated devices, we propose a specific design that enables blood filtration at a high flow rate (11.5 mL/min), which is much larger than usual microfluidic devices. Finally, we demonstrate that stable electrical measurements can be performed in whole blood at high flow rates to monitor the saturation of the filter by retained cells. Moreover, the fine analysis of the captured cells, usually entrusted to remote laboratories, could be transferred at the patient’s bedside along the sample processing if an in-situ analysis and real-time phenotyping of the collected cells through their electrical signature could be demonstrated. This aspect will be addressed through the conception and fabrication of dedicated filtering devices, thus broadening the application field of electrical sensing on a filtering membrane within a microfluidic chip
7
Hasan, Faisal S. "Upflow sand-roughing filtration." Thesis, Loughborough University, 1994. https://dspace.lboro.ac.uk/2134/34972.
Abstract:
Slow sand filtration requires low turbidity water for effective operation. In most cases this means pretreating the raw water to reduce its turbidity. Lately horizontal gravel filters have become very popular as a means of pretreatment. They are simple to operate, have a large mass storage capacity, and can cope with high turbidity shock loads. However, cleaning them can be a problem. An alternative pretreatment, which this study is concerned with, is upflow sand roughing filtration. It has the potential advantages of simple design, ease of operation and cleaning, and low area requirements. A study of upflow versus downflow was done using two small filter columns. The results showed that although downflow exhibited a better turbidity removal than upflow, upflow allowed longer filter runs and better utilisation of bed depth. This was in agreement with earlier findings. The effect of backwash water quality was also investigated. Both filters were run in upflow direction; one was washed with tap water, the other with polluted raw water. The results suggested, unexpectedly, that a filter washed repeatedly with polluted water produced slightly better turbidity removal than one washed with tap water. This indicated some form of maturation, which could be biological in nature, taking place. Experiments with horizontal gravel filters clearly showed the importance of biological mechanisms in maturation. Four new filter columns, 50mm in diameter, were constructed. These allowed further investigation of the effect of bed depth. Backwash rate and duration were investigated to find an optimum. Very little of the wash water was required to clean the filters, the majority being required to flush the turbidity out of the system. The long-term effect of backwash on filters was investigated, as was the effect of wash water quality. Tap water, raw water and raw water polluted with settled sewage were used to wash the filters. The results indicated that the filters washed with raw water and polluted water proved to be as good as regards turbidity removal as those washed with tap water. This suggested that raw water backwash could be used effectively for washing upflow roughing filters.
8
Dorea, Caetano Chang. "Chemically-enhanced gravel pre-filtration for slow sand filtration." Thesis, University of Surrey, 2005. http://epubs.surrey.ac.uk/843007/.
Abstract:
The simple operational and maintenance requirements of slow sand filtration (SSF), coupled with its high biological treatment efficiency makes it an attractive technology. The main limitation of SSF is its vulnerability to high suspended solids loadings. Pre-treatment in such instances can be achieved by gravel filtration. Cases of gravel pre-filtration underperformance have been attributed to significant fractions of influent suspended particles in the colloidal range. Maximum limits of turbidity for the application of gravel pre-filters have also been suggested. A simple intervention to overcome such water quality constraints can be through the dosing of a coagulant (aluminium sulfate) upstream of the pre-filtration stage; enhancing the pre-treatment efficiency, in what could be defined as direct (gravel) filtration. Previous studies have investigated its use as a pre-treatment for SSF; however, the results emphasise pre-filtration treatment efficiency and do not consider the effectiveness of the pre-treatment in protecting the slow sand filters. Also, because of the potential toxic effects of A1 residuals, its upstream use in relation to a biological SSF treatment has never been properly evaluated. The objectives of this study were: assess the efficiency as well as the effectiveness of chemically- enhanced up-flow gravel filters in series (UGFS) as pre-treatment for SSF and study the impact of aluminium residuals on the treatment performance and potential effects on biological activity. Preliminary experiments and first set of runs with chemically-enhanced pre-filter showed evidence of wall-effects due to the media size/column diameter ratio. This experimental design shortcoming was thought not to have affected the overall trends of results and was addressed for the set of pilot-experiments on which most conclusions are based. The results from the experimental work have shown that chemically-enhanced gravel pre-filtration can be effective only if coagulant dose is carefully controlled. Contrary to previous research, it was found that when resorting to chemically-enhanced pre-treatment (with alum) turbidities of less than 2 NTU (nephelometric turbidity units) should be targeted for in order to ensure an efficient and effective SSF pre-treatment. Such control will minimise A1 residuals that can otherwise cause a premature blockage of the slow sand filter by A1 hydroxide precipitates even with influent turbidities below 10 NTU. This was speculated to occur possibly due to size and mechanical properties of deposits retained on the uppermost layers of the SSF beds. A1 speciation analyses revealed that A1 residuals from chemically-enhanced pre-filtration were found to be mostly of inorganically- bound Al. This fraction consisted mainly of A1 in its form which is considered to be potentially more bioavailable (and possibly toxic) to aquatic (micro)organisms. However, slow sand filtration column trials found that filters dosed with the potentially more labile form of A1 did not show any significant difference in terms of treatment performance parameters and biological activity indicators. It has been demonstrated that chemically-enhanced pre-filtration (with alum) may not be an effective pre-treatment on the basis that it may cause an early blockage of the slow sand filters. There was no evidence of effect of A1 on biological treatment of the slow sand filtration process.
9
Pellet, Charlotte. "Nouvelles fonctionnalités de copolymères en brosse dans les suspensions minérales concentrées." Electronic Thesis or Diss., Paris 6, 2015. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2015PA066699.pdf.
Abstract:
La thèse porte sur une nouvelle classe de polymères à architecture en brosse, synthétisés à l'échelle industrielle et utilisés comme additifs dans les suspensions colloïdales pour le couchage du papier. Le polymère en brosse contrôle la déshydratation et le séchage des suspensions ce qui permet d'obtenir des revêtements d'une qualité incomparable. L'objectif est de modéliser sur un plan fondamental le rôle fonctionnel des polymères en relation avec les performances en application. Dans une première partie nous étudions leurs propriétés physicochimiques, structurales et rhéologiques en solution en discutant les spécificités dues à l'architecture en brosse. Dans une seconde partie nous analysons à l'aide d'un dispositif expérimental original les propriétés de rétention d'eau apportées par les polymères. Dans une troisième partie nous étudions le séchage de suspensions de carbonate de calcium sur des substrats solides, qui conduit en général à des motifs hétérogènes dits en " anneau de café ". Nous avons découvert que les polymères en brosse à très faible concentration suppriment ces défauts de séchage de façon remarquable. Le nouveau mécanisme physique à l'¿uvre, que nous appelons effet Marangoni auto-induit, résulte des propriétés interfaciales des polymères et de leurs interactions spécifiques avec les particules de carbonate de calcium. Pour conclure nous établissons un lien entre les propriétés de rétention d'eau et l'inhibition des défauts de séchage. Nous démontrons alors le caractère générique de nos résultats en les transposant à une suspension biologique, le sang, où les polymères pourraient présenter un intérêt dans le traitement de pathologies cardiovasculairesThis work focuses on a new class of bottlebrush polymers, synthesized on an industrial scale and used as additives in colloidal suspensions for paper coatings. The bottlebrush polymer controls the dehydration and drying of the suspensions, and leads to coatings of outstanding quality. Our aim is to model the functional role of these polymers from a fundamental perspective in relation with applicative performances. In a first part we study their physicochemical, structural and rheological properties in solution, emphasizing the specificities due to the brush architecture. In a second part we implement an original experimental setup to analyze the water retention properties brought by the polymers. In a third part we study the drying of calcium carbonate suspensions on solid substrates, which in general forms to heterogeneous patterns called “coffee-rings”. We discovered that at very low concentration, bottlebrush polymers remarkably suppress these defects. We call auto-induced Marangoni effect the new physical mechanism at work. It results from the interfacial properties of the polymers and their specific interactions with calcium carbonate particles. To conclude, we establish a link between water retention properties and drying defect inhibition. We demonstrate the generic character of our results which can be transposed to a biological suspension, blood, where these polymers could be of interest for cardiovascular disease treatment
10
Queguiner, Christophe. "Modélisation de l'écoulement d'une capsule dans un pore cylindrique." Compiègne, 1995. http://www.theses.fr/1995COMP0864.
Abstract:
Une méthode intégrale de frontière est utilisée pour modéliser l'écoulement instationnaire de capsules dans des pores. Une configuration entièrement axisymétrique est considérée où la capsule et le pore ont le même axe de révolution. La conduite est un cylindre avec une entrée et une sortie hyperboliques. La capsule a une géométrie de référence discoïdale et est remplie avec un liquide newtonien enfermé par une membrane très mince avec des propriétés élastiques néo-Hookéenne ou incompressible en surface. Les mouvements du liquide interne à la capsule et du fluide suspendant sont gouvernés par les équations de Stokes exprimées comme des intégrales de frontières. Celles-ci sont résolues par une technique de collocation, où des points sont distribués sur la membrane de la capsule, sur les parois de la conduite et sur les sections d'entrée et de sortie du domaine d'écoulement. La mécanique de l'interface de la capsule suit la théorie des grandes déformations des membranes élastiques. Le modèle numérique utilise un schéma temporel explicite où la position et la déformation de la capsule sont calculées à chaque pas de temps. Le modèle permet d'étudier l'effet de paramètres intrinsèques à l'écoulement (taille et géométrie de la capsule, propriétés élastiques de la membrane). La longueur d'entrée dans le pore, la perte de charge additionnelle à l'équilibre et les formes déformées de la capsule sont déterminées. De nouveaux résultats sont alors obtenus : le processus d'entrée d'une capsule dans un pore n'est pas sensible aux conditions en amont de l'écoulement; la longueur de pore nécessaire pour atteindre des conditions stationnaires, dépend de la taille de la capsule et du comportement de membrane. L'éclatement de capsules avec une membrane néo-Hookéenne a été observé. Il est dû à un phénomène d'élongation continue.
11
Muhammad, Nur. "Removal of heavy metals by slow sand filtration." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6981.
Abstract:
Slow sand filters (SSFs) are probably the most effective, simplest and least expensive water treatment process. Micro-organisms and other particulate materials are effectively removed by SSFs. Considerable development has been done on SSFs with respect to particle removal, but only a few works have been reported in the context of the removal of heavy metals which are a severely toxic pollutant of surface waters. No extensive laboratory or pilot studies have been carried out to determine the performance or the mechanisms of removal of heavy metals by SSFs. This research is concerned with an experimental investigation of the removal of heavy metals from surface water by SSFs. Four laboratory scale SSFs were built and run according to standard design criteria. Removal of four common heavy metals [copper (Cu), chromium (Cr), lead (Pb) and cadmium (Cd)] were monitored. The filters were fed synthetic water made from tap water mixed with settled sewage, and each filter was dosed with one of the heavy metal salts. The concentrations of Cu, Cr, Pb and Cd in the influent were selected as 10 mg/l, 100 μg/l, 60 μg/l, and 100 μg/l respectively considering their relative toxicity and WHO guidelines in drinking water. Settled sewage was added to vary the total organic carbon (TOC) of the feed water. The reduction of heavy metal concentrations were monitored at various TOCs, filtration rates and filter bed depths. The results showed that SSFs succeeded in removing heavy metals from water. The removals of Cu, Cr, Pb and Cd at the conventional flow rate and filter depth are 99.6,97.2,100 and 96.6 % respectively. The results also showed that an increase in TOC in the feed water improved metal removal while increases of flow rates caused a decrease of the removal of metals. The removal of heavy metals also decreased with a reduction in sand bed depth. The optimisation of design parameters for SSFs for the removal of heavy metals depends on the individual heavy metal and on the TOC content of the feed water. Model equations were developed for, and linear correlation was observed between each of the three control parameters and the removal of the selected metal. The removal of heavy metal by SSFs was achieved through the combination of a number of mechanisms. Settlement, adsorption to both sand and organic matter and microbial
12
Foreman, Gordon P. "Slow Rate Sand Filtration With and Without Clinoptilolite: A Comparison of Water Quality and Filtration Economics." DigitalCommons@USU, 1985. https://digitalcommons.usu.edu/etd/2896.
Abstract:
Slow rate sand filtration (SSF) amended with a 20 em surface layer of clinoptilolite, a natural zeolite, was compared to SSF with no amendment in a field scale SSF facility treating 85 m3/d of water. Parameters examined included turbidity, coliforms, and ammonium removal. The control filter with sand and the experimental filter amended with the zeolite were also compared with respect to duration of filter cycle, cold weather operation, and economics.
Amended and unamended filters were appr oximately equivalent with respect to ammonium and coliform removal at 10° C. The zeolite amended cell was superior to the unamended cell with respect to coliform and turbidity removal at 3° C. The zeolite amended cell had filter cycle durations four times longer and operation and maintenance costs 25% lower than the unamended cell.
Laboratory column studies were also conducted to compare a control column of construction sand to a homogeneous sand-zeolite mixture. and to SSF amended with zeolite or coarse sand. Construction sand and clinoptilolite were very similar in metal removal efficiency. Head loss developed most rapidly in the SSF column with construction sand only. Head loss developed more slowly resulting in longer filter cycles when the SSF was amended with a zeolite or coarse sand surface layer. A homogeneous sand-clinoptilolite mixture had filter cycles longer than construction sand, but shorter than SSF amended with a coarse surface medium.
Batch reactor tests were utilized to compare adsorption of reovirus to sand and clinoptilolite. Reovirus adsorption was approximately equivalent for the two media.
13
Kang, Young Woon. "Biological treatment of turkey processing wastewater with sand filtration." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1078903968.
Abstract:
Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains xxi, 187 p.; also includes graphic (some col.). Includes abstract and vita. Advisor: Karen M. Mancl, Dept. of Food, Agricultural, and Biological Engineering. Includes bibliographical references (p. 169-178).
14
Hurley, Steven Philip. "The role of macro-invertebrates in slow sand filtration." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409647.
15
Donison, Kori S. (Kori Shay) 1981. "Household scale slow sand filtration in the Dominican Republic." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28624.
Abstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.Includes bibliographical references (leaves 81-83).
Slow sand filtration is a method of water treatment that has been used for hundreds of years. In the past two decades, there has been resurgence in interest in slow sand filtration, particularly as a low-cost, household-scale method of water treatment. During January 2004, the author traveled to the northwestern Dominican Republic to evaluate the performance of BioSand filters installed over the past two years. BioSand filter performance was evaluated based on flow rate, turbidity removal and total coliform removal in communities surrounding the cities of Mao, Puerto Plata and Dajabon. Filter owners were interviewed about general filter use, water storage methods, filter maintenance practices, and water use. Data analysis revealed that even though the majority of filters were removing large portions of both total coliform and E. coli contamination, no filters met the WHO water quality guideline of less than one CFU/100 ml. Analysis also revealed that at low turbidities, turbidity removal and total coliform removal are not correlated. Examination of flow rate and bacterial removal near Puerto Plata revealed that filters with fast flow rates and intermittent chlorination were observed to have the lowest total coliform removal rates. Analysis of storage data revealed that failure to use safe water storage containers leads to recontamination of filtered water. During Spring of 2004, a laboratory was conducted to examine longer-term thermotolerant coliform and turbidity removal. The study compared removal rates between two BioSand filters, one of which was paired with a geotextile prefilter used in the construction of the Peruvian Table Filter. The study revealed that thermotolerant coliform removal rates by the BioSand filter without
(cont.) the geotextile stabilized after an initial period of lower bacterial removal efficiency. Thermotolerant coliform removal in the BioSand filter with the geotextile prefilter dropped throughout the experiment, suggesting that pairing a BioSand filter with a prefilter is detrimental to filter performance. Combining the results of the survey analysis and data gathered in the Dominican Republic with the results of the laboratory analysis of Spring 2004 suggests that BioSand filter users in the Dominican Republic should continue to use their filters. If possible, BioSand filter use should be combined with post-filtration chlorination to kill the remaining bacteria. The BioSand filter is a valuable and effective household-scale water treatment method for the Dominican Republic.
by Kori S. Donison.
M.Eng.
16
Sittivate, Dome. "Algae removal from surface water by horizontal-flow roughing filtration." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287809.
17
Micó, Reche Mª del Mar. "Photo-Fenton and Slow Sand Filtration coupling for hydroponics water reuse." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/128571.
Abstract:
The collaboration between the University of Barcelona and Acciona Agua was focused on optimizing greenhouses hydric resources. The functionality of a combined treatment had to be assessed, when applied to the discard stream of a recycling system of the Advanced Greenhouse leachates. The coupling consisted on an Advanced Oxidation Processes (AOP), photo-Fenton, based on hydroxyl radical oxidative potential, produced by the interaction between Fe2+ and H2O2, and a slow sand filtration column acting as a bioreactor. The recycling system will require the synergy of chemical and biological processes to be able to work efficiently with the particular characteristics of greenhouses effluents: high salinity content and the presence of pesticides.
Two recycling strategies proposed by the project defined two conductivity thresholds that the coupled system should be able to cope with. The first strategy proposed a simple semi-closed system that recycled nutrient solution from the hydroponics crops until a maximum value of 11 mS•cm(-1), phytotoxicity limit. Part of the current was then diverted to be treated by the integrated system. The second strategy introduced reverse osmosis membrane technology that concentrated that diverted stream, sending the permeate for its reuse directly to the greenhouse, while the brine had to be treated by the coupled process. In this case the maximum level of salinity in the effluents could reach conductivities close to those for seawater, around 50 mS•cm(-1).
The performance of photo-Fenton reaction was essayed in order to improve the knowledge regarding this treatment technique. On the first place, this AOP and the ozonation process were compared. Results shown that increasing toxicity of ozonation effluents confirmed the choice of photo-Fenton as the most adequate treatment for pesticide polluted effluents. Experimental design criteria allowed then to determine optimal working conditions depending on the content of the reaction media, and enabled to prove the existence of endogenous catalyst inhibition in the presence of fosetyl-Al. Salinity essays were finally performed, yielding positive results even for highest conductivity effluents. Those positive results were also reflected in the increase of the biodegradability of the treated effluents, what leaded to the next step of the research.
Biocompatibility of pretreated effluents was essayed by means of sequencing batch reactors (SBR). These devices were used to show how photo-Fenton indeed increased biodegradability of the effluents, and how it grown until a certain point when more hydrogen peroxide did not lead to better results. They were also utilized to assess the biocompatibility of high salinity pretreated effluents, as a first step towards the coupling with the slow sand filtration at high conductivities. Results obtained were extremely encouraging, given that even for the highest salinity concentrations (10 and 50 mS•cm(-1)), the performance of the bioreactor achieved an organic content reduction for more than 80% of the loaded concentration, which compared to the 10-20% removal achieved by photo-Fenton, justifies the need of combining both treatments.
Guided by those positive results, the load of the slow sand filtration column with different salinity pretreated effluents was performed. Also positive results were obtained. The achieved elimination of the organic content was more than 75% when loaded with 10 mS•cm-1 effluent, and the refractory fraction (the remaining organic matter that cannot be oxidized either by photo-Fenton reaction or by the biomass metabolism) was the lowest also for this high conductivity.
Molecular biology tools, MTBs, used in this thesis were based on cloning and sequencing techniques of 16S rRNA genes. They allowed characterizing the bacterial population of one of the assessed SBRs and of the different loading stages of the slow sand filtration column. They showed how with the increase of salinity, the population in the slow sand filtration column loosed diversity, despite the fact that the performance of the column was still proficient. This fact stated how a very different microbial consortium could be developing the same functions as others.
According to obtained results, it could be finally concluded that the coupling between photo-Fenton reaction and slow sand filtration column could be an effective treatment alternative for implementing the recycling strategies of hydroponics greenhouse leachates proposed by CENIT-MEDIODIA Project. For its part, MBTs were revealed as powerful tools to characterize microbial population and increase the understanding of the bioreactions taking part in bioremediation.Esta tesis se enmarca en la colaboración entre el Departamento de Ingeniería Química de la Universidad de Barcelona y el Departamento de I+D de Acciona Agua S.A.U, en el marco del Proyecto CENIT- MEDIODIA (2007-2010). Esta iniciativa la componen un consorcio de empresas un consorcio de empresas y centros de investigación que unieron esfuerzos de innovación en el desarrollo de un nuevo concepto de Invernaderos Hidropónicos Avanzados. La colaboración entre la Universidad de Barcelona y Acciona Agua se centró en la optimización de los recursos hídricos de dichos invernaderos. Así se evaluó la funcionalidad de un tratamiento combinado que integrara un Proceso de Oxidación Avanzada (reacción foto-Fenton), y un reactor biológico (columna de arena de filtración lenta), aplicados a la corriente de desecho de un sistema de recirculación de lixiviados provenientes del nombrado invernadero avanzado. Las particularidades de dicho sistema de reciclado harían que el sistema combinado tuviese que trabajar con efluentes con alto contenido en pesticidas (metomilo, imidacloprid y fosetyl-Al, fueron escogidos para simular los lixiviados de invernadero) y conductividades entre 11 y 50 mS•cm-1. De este modo el principal objetivo del proceso integrado sería el de conseguir la máxima eliminación de los compuestos xenobióticos y de la carga orgánica que los acompañe en el efluente tratado. Así pues, la experimentación se llevó a cabo frente a tres aspectos relacionados con el sistema combinado: estudio de la reacción foto-Fenton, ensayos con biorreactores, y empleo de herramientas de biología molecular (MBT, en sus siglas en inglés) aplicadas a la caracterización de la biomasa desarrollada en los biorreactores ensayados. Según los resultados obtenidos, se llegó a la conclusión de que la combinación de la reacción foto-Fenton y la columna de filtración lenta podría ser una alternativa de tratamiento eficaz para la aplicación de las estrategias de reciclaje de los lixiviados hidroponía presentadas en Proyecto CENIT-MEDIODIA. Además, MBT se revelaron como poderosas herramientas para caracterizar la población microbiana de distintos biorreactores y las funciones que desempeñan.
18
Cleary, Shawn A. "Sustainable Drinking Water Treatment for Small Communities Using Multistage Slow Sand Filtration." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/926.
Abstract:
Slow sand filtration is a proven and sustainable technology for drinking water treatment in small communities. The process, however, is sensitive to lower water temperatures that can lead to decreased biological treatment, and high raw water turbidity levels that can lead to premature clogging of the filter and frequent cleaning requirements, resulting in increased risk of pathogen breakthrough.
Multistage filtration, consisting of roughing filtration followed by slow sand filtration, can overcome these treatment limitations and provide a robust treatment alternative for surface water sources of variable water quality in northern climates, which typically experience water temperatures ranging down to 2°C. Prior to this study, however, multistage filtration had yet to be systematically challenged in colder climates, including testing of its performance under increased hydraulic loadings and elevated influent turbidity together with cold water conditions.
The primary goal of this research was to demonstrate the reliability of multistage filtration for small communities in northern climates with reference to the Ontario Safe Drinking Water Act. In this research, testing was conducted on two different pilot multistage filtration systems and fed with water from the Grand River, a municipally and agriculturally impacted river in Southern Ontario. One system featured pre-ozonation and post-granular activated carbon (GAC) stages, and shallower bed depths in the roughing filter and slow sand filter. The other system featured deeper bed depths in the roughing filter and slow sand filter, two parallel roughing filters of different design for comparison, and a second stage of slow sand filtration for increased robustness.
Removal of turbidity, total coliforms, and fecal coliforms under a range of influent turbidities (1 to >100 NTU), water temperatures (~2 to 20°C), and hydraulic loading rates (0. 2 to 0. 8 m/h) were investigated. In addition, the slow sand filters in each pilot system were challenged with high concentrations (~106 oocyst/L) of inactivated Cryptosporidium parvum oocysts.
The performance of both pilot multistage filtration systems was highly dependent on the biological maturity of the system and its hydraulic loading rate. In a less mature system operating in cold water conditions (<5°C), effluent turbidity was mostly below 0. 5 NTU during periods of stable influent turbidity (no runoff events) and a hydraulic loading of 0. 4 m/h, however, runoff events of high influent turbidity (>50 NTU), increased hydraulic loadings (0. 6 m/h), and filter cleaning occasionally resulted in effluent turbidity above 1 NTU. Furthermore, in a less mature system operating during runoff events of high turbidity, reducing the hydraulic loading rate to 0. 2 m/h was important for achieving effluent turbidity below 1 NTU.
However, in a more mature system operating in warm water conditions (19-22°C), effluent turbidity was consistently below 0. 3 NTU at a hydraulic loading rate of 0. 4 m/h, and below 0. 5 NTU at 0. 8 m/h, despite numerous events of high influent turbidity (>25 NTU). It remains to be seen whether this performance could be sustained in colder water temperatures with a fully mature filter. Removal of coliform bacteria was occasionally incomplete in a less mature multistage system, whereas, in a more mature system operating in warm water conditions (>9°C), removal was complete in all measurements. Furthermore, the average removal of Cryptosporidium was greater than 2. 5 logs in both systems (with hydraulic loading rates ranging from 0. 4 to 0. 8 m/h) and improved with increased filter maturity.
Each individual stage of the multistage system was an important treatment barrier in the overall process of turbidity and pathogen removal. The roughing filter was not only important for protecting the slow sand filter from solids loading and increasing its run length, but was also a significant contributor to coliform removal when the system was less mature. Removal of turbidity was significantly improved when the roughing filter was more mature, suggesting that biological treatment was an important treatment mechanism in the roughing filter. Although pre-ozonation was used mainly for the removal of organic carbon and colour, it achieved complete removal of coliform bacteria and was also suspected to be important for enhanced removal of turbidity. The second slow sand filter in series provided additional robustness to the process by reducing effluent turbidity to below 1 NTU during cold water runoff events of high turbidity and increased hydraulic loadings (0. 6 m/h), while achieving effluent below 0. 3 NTU during normal periods of operation. It also provided additional removals of coliforms under challenging operating conditions, and contributed an additional average removal of Cryptosporidium of 0. 8 logs, which resulted in cumulative removal of 3. 7 logs, approximately 1 log greater than all the other challenge tests.
Collectively, the entire multistage system performed well with water temperatures ranging down to 2°C, limited filter maturity, elevated raw water turbidities, and increased hydraulic loading rates. Its ability to meet the current Ontario turbidity regulations and greater than 2 log removal of Cryptosporidium over a range of operating conditions, with little or no process adjustment, is a testament to the robustness and minimal maintenance requirements of the process, which are desirable attributes for small water systems that are often located in rural areas. While this research demonstrated the performance of multistage filtration using pilot scale testing, it is important to note that full-scale plants tend to produce significantly better results than pilot facilities, due to long term biological maturation of the system.
Overall, multistage filtration is a sustainable and cost-effective technology that, through this research, appears to be a safe, reliable, and robust treatment alternative for small and non-municipal water systems in North America and the developing world. Further, based on its performance with challenging influent water quality and cold water conditions, multistage filtration holds particular promise for small communities in northern climates that are required to meet safe drinking water regulations, but are dependent on surface water sources of variable water quality and temperatures.
19
Rimmelé, Thomas. "Purification sanguine au cours du choc septique." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00809032.
Abstract:
Le choc septique est la première cause de mortalité en réanimation. Des techniques extracorporelles de purification sanguine sont aujourd'hui proposées pour améliorer le pronostic de cette pathologie. Leur mode d'action est basé sur l'immunomodulation de la réponse inflammatoire systémique de l'hôte, obtenue principalement par épuration nonsélective des médiateurs de l'inflammation. Nous rapportons les résultats de différentes études in vitro, animales et cliniques ayant évalué les techniques de purification sanguine suivantes :hémofiltration à haut débit, hémofiltration en cascade, hémofiltration hautement adsorbante,filtration et adsorption couplée, hémoadsorption, et hémodialyse à haute perméabilité.Ce travail de recherche translationnelle montre que les techniques de purification sanguine sont non seulement capables d'épurer les médiateurs de l'inflammation mais aussi l'endotoxine pour l'hémofiltration hautement adsorbante et l'hémoadsorption. Nous démontrons par ailleurs la faisabilité technique, la sécurité d'application et les intérêts del'hémofiltration en cascade et de l'hémodialyse continue à haute perméabilité. Les effets hémodynamiques bénéfiques des techniques de purification sanguine sont également retrouvés. Pour les années à venir, il conviendra d'optimiser les techniques les plus performantes en tenant compte de leurs avantages et inconvénients respectifs. Sur le planphysiopathologique, l'effet plus direct de ces thérapies sur les leucocytes sera à approfondir. Il semble maintenant admis que convection, diffusion et adsorption ne doivent plus être opposés mais plutôt être considérés comme des mécanismes complémentaires
20
Djembarmanah, Rachmawati Sugihhartati. "Activated unsaturated sand filter as an alternative technology to remove copper, manganese, zinc and nickel from waters." Thesis, Swansea University, 2012. https://cronfa.swan.ac.uk/Record/cronfa42435.
Abstract:
An activated unsaturated sand filter (AUSF) is one of only a few of the filtration technologies utilized to treat waters and wastewaters that use unsaturated filter media. AUSF employs sand coated with potassium permanganate and operates with an open chamber allowing free air flow into the column of sand. The AUSF also benefits from operation without the need for a sedimentation unit. Previous studies have demonstrated the efficient removal of iron and manganese using an AUSF, however, to date there are still very limited studies available that use AUSF technology for the removal of metals from waters and wastewaters. Thus, there is an urgent need and opportunity to exploit this technology further. This research was conducted in order to develop and study the characteristics and subsequent operational performance of a novel AUSF media. The study focuses on the removal of copper, manganese, zinc and nickel from a synthetic wastewater and extends current knowledge to a passive aeration process rather than the active aeration used in the previous study by Lee et. al. (2004). The characterisation involved the use of sieving, Brunauer- Fmmett-Teller (BET) analysis, water evaporation studies and scanning electron microscopy (SEM) for structural analysis such as particle size, surface area, porosity and topography. Energy dispersive X-ray analysis (EDX), acid/alkali resistance, isoelectric point determination and acid digestion analysis were used to determine the chemical constituency, chemical stability, electrical charge properties and the binding efficiency of the media. Finally, tracer studies were employed to determine the flow characteristics through the particle media. The manganese coated sand was proven effective for the removal of copper in both agitated tank batch studies and continuous column studies. The batch studies showed that the equilibrium sorption of copper followed a Langmuir isotherm and the sorption rate was best modelled using the pseudo-second-order kinetic model. This suggests that adsorption is taking place as a single homogeneous layer on the surface of the sand particle via the chemisorption method. The Weber-Morris and Bangham models were used to determine the rate-controlling mechanism and this was found to be predominantly intra-particle diffusion. This was confirmed for column studies using the Bohart-Adams model that demonstrated that liquid-film mass transfer was not significant. Several mechanisms of metal removal are proposed and these include precipitation, electrostatic attraction, adsorption, ion exchange and complex ion formation. The column studies demonstrated that dispersion was low under the operating conditions and plug flow performance could be inferred, thus justifying the use of the AUSF model employed. Copper was best removed when operating as an unsaturated particle bed and the removal capacity was increased by approximately 100% when compared to a saturated particle bed. Moreover, the pH increase that occurs on exposure of the process water to the unsaturated column further improves removal capacity. Thus, there is no requirement for an expensive pH adjustment as a pre-treatment process prior to this unit operation. In addition, the removal capacity of the AUSF was demonstrated to increase with lower metal concentrations, lower water flow rates, smaller sand particles, an increase in manganese to sand ratio and an increase in particle bed height. The AUSF performance in removing metals followed the order Cu > Mn > Zn > Ni for individual and mixed component solutions and Cu > Ni > Zn > Mn for a synthetic wastewater typical of the electroplating industries. In conclusion, the novel manganese coated AUSF developed is effective in the removal of metals from solution and offers the potential of a sustainable low cost treatment method for the purification of waters and wastewaters.
21
Aydin, Mehmet Emin. "An investigation into the influence of sand size, bed depth, rates of filtration and temperature on the quality of filtrate from a slow sand filter." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/7307.
Abstract:
The objective of this research project was to investigate the influence of the principal design and operational parameters on the quality of the filtrate from a slow sand filter. These parameters are sand effectivc size, depth of sand bed, rate of filtration, water temperature and influent quality. Attempts were then made to establish relationships between the variables employed by means of regression analyses of the experimental data. To carry out the investigation three laboratory scale filter columns were constructed each measuring 150 mm in diameter and 3010 mm height. The filtration medium in each column consisted of a 1.2 m depth of sand on a 0.3 m depth of gravel. For the three individual columns three different sand sizes were employed. These were 0.17 mm effective size (ES), 0.35 mm ES and 0.45 mm ES. Water to be filtered was abstracted from the Burleigh Brook, adjacent to the Civil Engineering laboratories. As required small amounts of settled sewage, obtained from the Loughborough Water Reclamation Works, were added to increase both the turbidity and the count of indicator bacteria. The filters were operated at five different filtration rates at three different temperatures. These temperatures were 25 degrees C, 15 degrees C, 5 degrees C and the filtration rates repeated for each temperature were 0.1, 0.2, 0.3, 0.4, 0.5 m/h. The filters were operated for not less than one month at each filtration rate. In order to assess the efficiency of the filters water samples were taken and analysed from the influent and from the filtrate and also from a series of sampling taps positioned at various depth down the sand media. These water samples were tested for total coliform bacteria, for faecal coliform bacteria, suspended solids and turbidity. Regression analyses were then carried out on the data obtained and regression models were developped for 100 mm and 1200 mm sand depths of each filter for each period. Occasional tests (i. e. at least once for each flow rate) were also carried out for nitrate and ammoniacal nitrogen, colour, pH, conductivity, total organic carbon (TOC) and dissolved oxygen. Following the completion of the filtration operation at three temperatures and five filtration rates the sands of the filtration media were also examined. Sand samples were taken for examination from 0, 50, 100, 150, 200, 300, 400, 600, 800, 1000 and 1200 mm below the sand surface of each filter. Then in order to assess both the penetration of the removed solids into the filter bed and to investigate the concentration of the biological film developed within the sand bed, sand samples were analysed for suspended solids, turbidity, standard plate count bacteria and particulate organic carbon. Regression analyses were also carried out on these data and variation of each parameter against each filter bed was modelled. The solid and biological deposits on the sand samples were also viewed with a Scanning Electron Microscope.
22
Wheeler, David. "The potential role of slow sand filtration in reducing rotaviral diarrhoea in less developed countries." Thesis, University of Surrey, 1989. http://epubs.surrey.ac.uk/843737/.
Abstract:
A slow sand filter system was developed which was suitable both for experimental purposes and full scale community water supply. The performance of the system was enhanced by the incorporation of pretreatments such as gravel prefiltration, sub-sand prefiltration and direct protection of filters by the incorporation of synthetic fabric layers. The system was used to examine aspects of the biological and physico-chemical nature of Slow Sand Filtration with particular reference to the removal of Rotavirus and a variety of bacterial and viral indicators. The results of the developmental phase and experiments conducted with operational filters and in the laboratory confirmed the importance of biological mechanisms, in particular adsorption to biological surfaces present in the upper horizons of slow sand filters. It was observed that both the efficiency and pattern of removal of Rotavirus in Slow Sand Filtration were similar to those observed for faecal indicator bacteria, bacteriophage and turbidity ie colloidal clay and other particles. Thus it was concluded that negatively charged particulate colloidal entities appear to behave similarly despite differences in size and surface characteristics and that Rotavirus is no more or less likely to pass through slow sand filters than any other particle. Thus, a well operated slow sand filter may be expected to achieve a reduction in Rotavirus densities of 2 log10 orders of magnitude. The principal mechanisms of removal of Rotavirus in the upper horizons would appear to be transportation by diffusion and adsorption to biofilms and biomass. Microbial predation is not likely to play a dominant role in the removal of Rotavirus from the aqueous phase but may be important in inactivation. A detailed examination of the incidence, prevalence and seasonal occurrence of rotaviral and other diarrhoeas in less developed countries led to the observation that unlike some of the bacterial pathogens, transmission of Rotavirus does not have a strong association with water quality. Hence. The case for low level waterborne transmission and thereby maintenance of endemicity in the community remains entirely theoretical. Moreover, bearing in mind the likelihood that slow sand filters will be operated sub-optimally in many cases, a moderate reduction in Rotavirus densities eg 1 - 2 log10 units may not be significant in terms of diarrhoeal disease risk, particularly for children and especially in the rural sector. In view of these observations and other factors eg the low infective dose of the virus and the undoubted pre-eminence of person-to-person spread, it was concluded that as a single process, Slow Sand Filtration is probably not capable of significantly reducing the incidence of rotaviral diarrhoea in less developed countries.
23
Campos, Luiza Cintra. "Modelling and simulation of the biological and physical processes of slow sand filtration." Thesis, University College London (University of London), 2002. http://discovery.ucl.ac.uk/43778/.
Abstract:
Slow sand filtration (SSF) is the earliest form of engineered potable water treatment and remains one of the most efficient processes for improving the physical, biological and chemical quality of water. However, whilst widely used throughout the world, knowledge of the filtration mechanisms remains limited. This is important in understanding and managing the processes that are responsible for gradually blocking the filter reducing its operational life and filtration efficiency. The objective of this thesis was to develop a mechanistic simulation model of the fundamental physico-chemical and biological processes responsible for the filtration mechanisms operating in slow sand filters. The model solves a set of equations describing schmutzdecke development above the sand and microbial biomass growth within the sand. The model assumes that the schmutzdecke layer contributes to the water purification process and its growth is described as linear function in relation to time. The dynamic interactions between the principal groups of microorganisms including: algae, bacteria and protozoa, were modelled using Monod-type kinetic equations. The filtration performance of the filter media was defined in the model by the removal of particulate material from water and was represented by a combination of headloss and filtration coefficient functions. The model was calibrated and verified using data from full and pilot plant-scale SSF operated by Thames Water Utilities Ltd. Simulation results showed that interstitial biomass was the smallest part of the bulk specific deposit in both covered and uncovered filters. However, microbial dynamics played an important role in the filtration performance. Schmutzdecke development had a major influence on the operation of uncovered filters and was responsible for the significant increase of headloss observed during operation. The model provides a representation of the fundamental nature of SSF processes and could form the basis of an operational management system to optimise SSF.
24
Lukacs, Heather A. 1979. "From design to implementation : innovative slow sand filtration for use in Developing countries." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/84799.
25
Demitry, Mariana. "Evaluating Water Filtration and Disinfection for Household, Using Slow Sand Filters plus Solar Disinfection." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/6911.
Abstract:
In this research, a household water treatment system was built and evaluated as a trial for improving the drinking water quality of the Nile River for the low-income communities. The system consisted of household-scale slow sand filters, and transparent polyethylene terephthalate-bottles for solar disinfection. The evaluation of the system depended on the removal/inactivation of some surrogates for the reference pathogens, and turbidity. The reference pathogens are pathogens specified by the World Health Organization to evaluate the efficiency of the household water treatment options. They were chosen to represent the classes of pathogens in water (bacteria, viruses, protozoa). The surrogates used in the evaluation of the system are Escherichia coli (E.coli), Clostridium perfringens and Escherichia coli bacteriophage (MS2). The candidate surrogates are also specified by the World Health Organization.
The designed household-scale slow sand filter was very efficient in removing the different turbidity levels to ≤0.4NTU. The evaluated system is classified as highly protective because it was able to achieve higher than 4 log removal for E.coli and Clostridium perfringens, and higher than 5 log removal for MS2.
26
Khalaphallah, Rafat. "Greywater treatment for reuse by slow sand filtration : study of pathogenic microorganisms and phage survival." Phd thesis, Ecole des Mines de Nantes, 2012. http://tel.archives-ouvertes.fr/tel-00735857.
Abstract:
In recent decades, most countries of the world have experienced a shortage of water and increase its rate of consumption. Today, every country in the world are interested in this problem by trying to find alternatives to address this shortage. One solution is reuse greywater (GW) for irrigation after treatment. GW is all water generated from Household except toilet water. The risks associated with the reuse of these waters are the presence of pathogens that can infect humans, animals and plants. In this thesis focused on studying treatment by slow sand filtration and the survival of representatives of pathogens, such as E. Coli, P. aeruginosa , E. Faecalis and Bacteriophage MS2 which could be found in the greywater. The study factors was a physico-chemicals factors such as; temperature (6±2,23±2,42±2°c), salinity (1.75 and 3.5% Nacl), oxygen (aerobic and anaerobic condition), nutrient ( rich media , 50%: 50% salt and poor media ), light with photocatalysis ( UV and Visible lights) and slow sand filter (Egyptian desert sand and swimming pool sand). A combination of high temperature, sunlight and photocatlysis are mainly responsible for the rapid decline of bacteria and MS2 coliphage. Slow sand filter have clearly less influence on the survival of bacteria in the greywater, but it effective to decline turbidity and COD for short times.
27
Clarke, Emma Victoria Faye. "An investigation into silver nanoparticles removal from water during sand filtration and activated carbon adsorption." Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/29959.
Abstract:
Wastewater treatment plants (WwTP) act as the principle buffer between anthropogenic sources of Silver Nanoparticles (AgNPs) and environmental targets. AgNPs, given their effective anti-microbial properties, have the potential to negatively impact WwTP processes and organisms within the natural environment. A clear understanding of the fate and transport of AgNPs as they pass through WwTPs is crucial in evaluating AgNPs impacts for WwTP process, the natural environment and in the development of a comprehensive environmental risk assessment for AgNPs. The main aim of this thesis was to carry out an analysis on the fate, transport and transformation of AgNPs through WwTP relevant filtration medias in order to understand more about the toxicological implications for both WwTP processes and receiving environments. AgNPs were synthesised in-house, via an in-situ reduction method, which produced a homogeneous dispersion of nanoparticles of average particle diameter 9.98nm, with a standard deviation of 3.11nm. Column studies and adsorption isotherm experiments were conducted to investigate the fate and transport of silver nitrate, AgNPs and bulk silver across media beds of quartz sand and granulated activated carbon (GAC), both chosen for their relevance in wastewater treatment protocols. TEM imaging and EDS analysis was employed to characterise the AgNPs physically and elementally within the column influents and effluents. An original contribution made to the existing knowledge on AgNPs is that in contrast to bulk silver and silver nitrate, uncoated AgNPs were observed to be highly mobile through the quartz sand media. This high mobility was in contrast with the prior expectation that van der Waals forces of attraction between the positively charged AgNPs and the negative charge of the silica surfaces within the sand bed would lead to some measure of retention within the column matrix. The resulting high mobility of the AgNPs was attributed to particle surface contamination of boride ions originating from the reduction agent used during the synthesis process. This highlights (and reinforces) the importance of better understanding on the implications of the various methods of synthesis and use of capping agents for AgNPs characteristics and the impact this has on fate and transport. AgNPs were also noted to have been significantly altered after their passage through the quartz sand media, with up to 83% of the sample increasing in size, from 9.98nm to an average of 18.26nm and a maximum of 144nm. Particle size measurements were made using the measuring tool available in the GNU Image Manipulation Program (GIMP). This size increase was attributed to the formation of nano-alloy clusters with residual gold and iron compounds, naturally present within the sand bed. In the case of silver-gold alloy clusters, this is expected to exhibit positive implications for future environmental fates of the resulting AgNPs, where the presence of gold in alloy clusters has been observed to significantly deactivate AgNPs silver ion release. In contrast to the sand, it was observed that the GAC was an effective absorber of AgNPs. However, this was observed to be a size dependant relationship, where the GAC was not observed to be effective for adsorption of bulk silver at particle sizes of 300 – 800nm. In this thesis, in addition to the experimental work, a novel, low complexity technique was developed for the detection and quantification of AgNPs in laboratory aqueous solutions. This protocol utilises a laboratory bench top photometer and gave AgNPs concentration results that reliably and accurately reflected that of ICP-MS and ICP-OES results within a detection range of 0.01 and 20mg/L; where the correlation coefficient between the instrument absorbance response and ICP-MS/OES concentration (at 450nm) was R2 0.994.
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Henderson, Elizabeth. "A KINETICS STUDY OF SELECTED FILTRATION MEDIA FOR NUTRIENT REMOVAL AT VARIOUS TEMPERATURES." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2344.
Abstract:
In recent years the nutrient levels of the Upper Floridan aquifer have been increasing (USGS, 2008). An example of this is found in Ocala, Florida where Silver Springs nitrate concentrations have risen from 0.5 mg/L in the 1960 s to approximately 1.0 mg/L in 2003 (Phelps, 2004). Because stormwater is a contributor to surficial and groundwater aquifer recharge, there is an increasing need for methods that decrease nitrogen and phosphorus levels. A laboratory column study was conducted to simulate a retention pond with saturated soil conditions. The objectives of the column studies reported in this thesis were to investigate the capabilities of a natural soil and soil augmentations to remove nitrogen and phosphorus for a range of concentrations at three different temperatures. An analytical attempt to model the columns through low order reaction kinetics and derive the corresponding temperature conversion constant to relate the rate constants is also presented. The Media Mixes were selected through a process of research, preliminary batch testing and then implemented in column studies. Three columns measuring three feet in length and 6 inches outer diameter were packed with a control and two media mixes. Media Mix 1 consisted of 50% fine sand, 30% tire crumb, 20% sawdust by weight and Media Mix 2 consisted of 50% fine sand, 25% sawdust, 15% tire crumb, 10% limestone by weight. The control column was packed with natural soil from Hunter s Trace retention pond located in Ocala, Florida. The reaction rates for nitrate are best modeled as first order for Media Mix 1, and zero order for the Control and Media Mix 2. The reaction rates for orthophosphate are best modeled as zero order, second order and first order for the Control, Media Mix 1, and Media Mix 2 respectively. The best overall media for both nitrate and orthophosphate removal from this study would be Media Mix 1. Media Mix 2 does have the highest average orthophosphate removal of all the mixes for all of the temperatures; however Media Mix 1 outperforms Mix 2 for the other two temperatures. The best column for Nitrate removal is the Media Mix 1 column. The temperature conversion factors for nitrate were found to be 1.11, 1.1, and 1.01 for Media Mix 1, the Control and Media Mix 2 respectively. The temperature conversion factors for orthophosphate were found to be 1.02, 0.99, and 0.95. As well as temperature conversion factors, the activation energies and frequency factors for the Arrhenius Equation were investigated. Average values corresponding to each column, species, and temperature would be inaccurate due to the large variation in calculated values.M.S.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engr MSEnvE
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Harris, Joseph Russell. "Preposition-position design strategies in a master plan for redevelopment, McMillan Sand Filtration Site, Washington, DC /." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/209.
Abstract:
Thesis (M. Arch.) -- University of Maryland, College Park, 2004.Thesis research directed by: Architecture. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Dunn, Andrew John. "The development of a predictive model for the removal of helminth eggs during rapid sand filtration." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293191.
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November, Justin Sidney. "A study of soil to geotextile filtration behaviour in conjunction with Berea sand in South Africa." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86381.
Abstract:
Thesis (MScEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Geotextiles perform a number of functions in various applications in civil engineering practise. It is often cost effective and more environmentally friendly versus conventional construction methods. One of the main functions of a geotextile is filtration whereby the geotextile is expected to hold back the soil particles and simultaneously has to allow sufficient water to pass through it. Soils are all different and can be problematic when it comes to designing geotextile filters. One such problematic soil is encountered in KwaZulu- Natal, situated along the east coast of South Africa. The Berea sand is problematic as it can highly variable in its engineering properties over a small area. Geotextiles are becoming more and more common practice in South Africa and little is known about the filtration performance of commercially available geotextiles in conjunction with Berea sand. Local guidelines that are available are out of date and do not provide enough information to assist design engineers in decision making. Many international guidelines are available and it is difficult to choose which one is best suited to Berea sands. This primary objective of this study is to investigate the filtration performance of four variants of commercially available geotextiles and three variants of Berea sand. The applicability of some of the international filter design criteria will also be assessed. The soil to geotextile compatibility testing was carried out as per ASTM D5101 (2006) - Standard Test Method for Measuring the Soil-Geotextile System Clogging Potential by the Gradient Ratio. In total 12 permutations were executed. The results showed that only 5 test permutations met the gradient ratio and permeability criteria. The test results also conclude that the permeability is just as important as the gradient ratio. Thick geotextiles should be considered when used as filters in Berea sands. The available international geotextile filter design criteria were assessed and all showed poor correlation between laboratory results and suggested criteria. Designing geotextile filters in conjunction with Berea reds is challenging and it is recommended that design engineers perform laboratory performance testing in conjunction with their designs.
AFRIKAANSE OPSOMMING: Geotekstiele verrig vir 'n aantal funksies in verskeie programme in die siviele ingenieurswese praktyk. Dit is dikwels meer koste-effektief en omgewingsvriendelik, teenoor konvensionele konstruksie metodes. Een van die belangrikste funksies van 'n geotekstiel is filtrasie, waardeur van die geotekstiel verwag word om van die grond terug te hou, en gelyktydig genoeg water daardeur te laat vloei. Grond verskil en dit kan problematies wees wanneer dit kom by die ontwerp van geotekstiel filters. Een so ‘n problematiese grond kom voor in KwaZulu-Natal, geleë langs die ooskus van Suid-Afrika. (Die) Berea sand is problematies, want dit verander geweldig baie ten opsigte van ingenieurseienskappe oor 'n redelike klein area. Gebruik van geotekstiele word al hoe meer ‘n algemene praktyk in Suid- Afrika, terwyl min bekend is oor die filtrasie prestasie van kommersieel beskikbare geotekstiele in samewerking met Berea sand. Plaaslike riglyne wat beskikbaar is, is verouderd en onvoldoende inligting is beskikbaar aan ontwerpingenieurs vir besluitneming . Baie internasionale riglyne is beskikbaar en dit is moeilik om te besluit watter een die beste van toepassing is vir Berea sand. Die doel van hierdie studie is om die filtrasie prestasie van vier modelle van kommersieël beskikbare geotekstiele en voorbeelde van drie soorte Berea sand te ondersoek. Die toepaslikheid van 'n paar van die internasionale filter ontwerp kriteria sal ook beoordeel word. Die toetsing van grondverenigbaarheid met geotekstiel is uitgevoer soos aangedui in ASTM D5101 (2006 ) – Standaard Toets Metode vir die meet van die grond-Geotekstiel verstopping potensiëel deur die gradient verhouding. In totaal is 12 permutasies uitgevoer. Die resultate het getoon dat slegs 5 toetspermutasies beide gradiënt verhouding en permeabiliteit kriteria bevredig het. Dikker geotekstiele word ook aanbeveel vir gebruik as filters in Berea sand. Van die toets resultate kan ook afgelei word dat die permeabiliteit net so belangrik soos die gradiënt verhouding is. Beskikbare internasionalegeotekstiel filter ontwerp kriteria is nagegaan en al die metodes het swak korrelasie tussen laboratorium resultate en die voorgestelde kriteria getoon. Om geotekstiel filters in samewerking met Berea Reds te ontwerp is 'n uitdaging en dit word aanbeveel dat ontwerpingenieurs laboratorium prestasietoetsing in samewerking met hul ontwerpe uitvoer.
32
Rottman, Jeffrey J. "Fundamentals and Application of Porous Media Filtration for the Removal of Nanoparticles from Industrial Wastewater." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/255157.
Abstract:
Increasing use of engineered nanomaterials presents concerns as some nanoparticles appear to be harmful to both human health and the environment. Effective treatment methods are required to remove problematic nanoparticles from (waste)water streams. Porous media filtration, commonly used for the removal of particulate matter, shows promise for nanoparticle treatment. The goal of this work is to investigate the potential of porous media filtration for the abatement of nanoparticles from aqueous waste streams. To this end, an automated method was developed that allows real-time and in-situ monitoring of nanoparticle transport and retention in porous media using online measurement of UV-visible absorbance or fluorescence. Development of fluorescent-core nano-silica (n-SiO₂) in controllable sizes provided an excellent tracer for nanoparticle transport in porous media. Measurement of n-SiO₂ by destructive techniques is complicated by high natural Si background levels. Fluorescence monitoring enables real-time measurement, facilitating rapid evaluation of n-SiO₂ transport. Synthesized n-SiO₂ remain in their primary sizes making an evaluation of the behavioral change of particles due to transition into the "nano" range possible. A comparison of the role of particle size on transport in porous media displayed the importance of particle number concentration as the dominance of site-specific adsorption may be obscured by simple mass concentration evaluation.T he effectiveness of different bed materials, namely, sand, activated carbon (AC), and diatomaceous earth (DE), for the removal of TiO₂ nanoparticles (n-TiO₂) from aqueous streams was investigated. DE proved promising for n-TiO₂ capture shown by its high bed capacity (33.8 mg TiO₂ g⁻¹(medium)) compared to AC (0.23 mg TiO₂ g⁻¹(medium)) or sand (0.004 mg TiO₂ g⁻¹(medium)). The presence of organic and synthetic contaminants produced varying effects on n-TiO₂ retention, mostly due to either enhanced electrostatic or steric interactions. Application of a process simulator combining physical straining with site-specific interactions, delineating physisorption from chemisorption and diffusion limited interactions, enabled the accurate fit of n-TiO₂ transport in sand, AC and DE. The fitting process revealed the advantage of DE due to increased physisorption and physical straining of n-TiO₂. Modeling of this system afforded the elucidation of controlling retention mechanisms and provides a basis for future scaling and system design.
33
Dikinya, Oagile. "The effects of self-filtration on saturated hydraulic conductivity in sodic sandy soils /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0051.
34
Lenze, Christian. "Entwicklung hydrochemischer Parameter nach der Applikation von Klärschlamm auf unterschiedliche geologische Substrate /." Dortmund : Dortmund : Inst. für Wasserforschung ; Dortmunder Energie- und Wasserversorgung, 1997. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=008199357&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Paula, Donizeti de. "Avaliação da dupla filtração para tratamento de água superficial utilizando filtração ascendente em areia grossa." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-31102016-142553/.
Abstract:
Este trabalho consiste na avaliação do desempenho de uma instalação piloto de dupla filtração no tratamento de água superficial, apresentando turbidez entre 8,5 e 21 uT. A instalação piloto constituída de um sistema de filtração de duas fases, com filtração direta ascendente em areia grossa seguida da filtração rápida descendente em areia fina. A taxa de filtração variou de 120 a 360 m3/m2.dia no filtro ascendente e de 200 a 400 m3/m2.dia no filtro ascendente. Foram executadas descargas de fundo intermediários no filtro ascendente durante a carreira de filtração para avaliar a instalação piloto. Além disso, simulou pico de turbidez, para avaliar as condições. Baseado no trabalho experimental concluiu-se que: (i) a eficiência global do sistema de dupla filtração ascendente em areia grossa foi satisfatória, apresentando efluente final com turbidez inferior a 1 uT e cor verdadeira inferior a 1 uH; (ii) a distribuição da perda de carga nas camadas do meio granular do FAAG não apresentou diferenças significativas para as variadas taxas de filtração e modo de operação (com e sem execução de DIFs); (iii) os ensaios que foram realizados com a execução de DIFs apresentaram carreiras de filtração mais longas.This work concerns the study of the performance of a double filtration pilot plant whom treating surface water, presenting turbidity between 8,5 and 21,0 NTU. The pilot plant consisted of a two-stage filtration system, with an upflow coarse sand direct filtrer followed by a dowflow fine sand filter. Filtration rats varied from 120 to 360 m/day in the upflow filter and from 200 to 400 m/day in the downflow filter. Intermediate downflow in the upflow filter were performed during the run length do evaluate the performance of the pilot plant in addition, a peak of turbidity in the for influent selected filter operating varabile, was studied here in. Based on the experimental work carried out, it was concluded that: (i) the global efficiency of the system of double filtration with upflow filtration in coarse sand was satisfactory, presenting final efflents with inferior turbidity to 1,0 NTU and inferior true color to 1 uH; (ii) the distribution of the load loss in the layers of the granular middle of FAAG didn\'t present significant differences for the varied filtration taxes and operation way (with and without execution of DFIs); (iii) the rehearsals that were accomplished with the execution of DFIs presented longer filtration runs.
36
Isaeva, Margarita, and Castro Natasha Montes. "Water Treatment for the Removal of Iron and Manganese." Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-5357.
Abstract:
The purpose of the study is to find a suitable method for removal of iron and manganese considering local economic and environmental aspects. El Salvador is situated in Central America with a coast line towards the Pacific Ocean. The country borders Guatemala and Honduras. Aguilares is a town situated in the department of San Salvador, with a population of approximately 33,000 people. Currently, the population is provided with water for about two hours per day, since it is the highest capacity of the existing wells. During these two hours many households fill a small tank with water to use for the remainder of the day. The water is not safe to use for oral consumption because of the levels of bacteria and other contamination. One of the wells, situated in the community of Florída is not in use at this date because of the high levels of Iron and Manganese in the ground water which cannot be removed with the present technique.Ground water is naturally pure from bacteria at a depth of 30 m or more, however solved metals may occur and if the levels are too high the water is unsuitable to drink. The recommended maximum levels by WHO (2008) [1] for Iron and Manganese are 2 mg/l and 0.5 mg/l respectively.Literature and field studies led to the following results; Iron and manganese can be removed by precipitation followed by separation. Precipitation is achieved by aeration, oxygenation or chemical oxidation and separation is achieved by filtration or sedimentation.The different methods all have advantages and disadvantages. However the conclusion reached in this report is that aeration and filtration should be used in the case of Florída. What equipment and construction that should be used depends on economic and resource factors as well as water requirements, which is up to the council of Aguilares to deliberate.
37
Knappett, Peter. "Evaluating the Effects of Grain Size and Divalent Cation Concentration on the Attenuation of Viruses and Microspheres through Crushed Silica Sand." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/906.
Abstract:
Over the last decade in North America, an increasing number of microbiological drinking water regulations have been used to manage groundwater resources that are potentially influenced by surface water. Regulations such as the Ontario Ministry of Environment Regulation 505, which requires at least a 60 day groundwater travel time between surface waters and drinking water wells, have been created with limited understanding of subsurface pathogen transport processes. Groundwater Under Direct Influence studies (GUDI or GWUDI in USA) are conducted to assess the need to treat well water at an extraction point. Currently, there is a lack of knowledge regarding factors that affect the transport of pathogens through porous media at the surface water-groundwater interface. Such information is required to supply sufficient quantities of drinking water in a cost effective and safe manner. Factors that affect pathogen transport through porous media include: properties of the pathogen (i. e. surface charge, size, and morphology), properties of the granular media (i. e. mineralogy, size, texture, angularity) and properties of the water (i. e. pH, ionic strength and content, and natural organic matter). This study examines the effects of ionic strength, grain size and influent virus concentrations on pathogen transport in porous media. Fourteen column tests were conducted using the bacteriophage MS2 and 1. 5 µm microspheres; two commonly used non-pathogenic surrogates representative of human viruses and bacteria, respectively. Two size distributions of crushed silica sand, with median grain diameters of 0. 7 and 0. 34 mm, and two ionic strengths of 8 and 95 mmol/L were used. A 22 partial factorial design was used with a minimum of two replicates of each combination of the parameters.
The results show that complete breakthrough of both viruses and microspheres occurred in medium sand at low ionic strength. It was found that increasing ionic strength by Ca2+ addition precluded breakthrough of MS2 in both the medium and fine sands. This represents a greater than 8 log reduction in peak effluent concentration and essentially complete attenuation.
In fine sand, with low ionic strength water, a 5 log reduction in peak MS2 concentrations was observed. In the same sand at high ionic strength, no MS2 broke through the column, corresponding to a greater than 8 log removal. Since complete attenuation occurred in both grain sizes at high ionic strength, the effect of higher ionic strength in the fine sand was indistinguishable from the effect observed from raising the ionic strength in the medium sand.
In contrast to the viruses, microsphere transport was essentially unaffected by increasing ionic strength under the conditions investigated. A 1 log reduction in peak concentration was observed in the high ionic strength water in the medium sand. In spite of this, grain size had a profound effect on the attenuation of microspheres. There was no evidence of microsphere breakthrough in any of the fine sand columns at the low or high ionic strengths, yielding a greater than 5 log reduction in microsphere concentration associated with grain size alone. The effect of varying virus concentration was also investigated. It was found that varying the concentration of viruses between 105 and 107 pfu/ml had no discernable effect on their observed transport characteristics; normalised peak breakthrough concentration, percent attenuation and retardation relative to a bromide tracer.
Based on the results from this Thesis, in a riverbank filtration environment, there is reason to expect that, at comparable water qualities and in similar porous media, multiple logarithmic reductions of viruses and bacteria would occur over the much longer (than column length) flowpaths associated with RBF. There is also reason to expect this attenuation capability to vary based on riverbank grain size and water chemistry.
38
Cochran, Jeff W. "Evaluation of pre and post treatment filtration performance of Kinetico Macrolite ceramic media compared to traditional sand/anthracite and GAC filters in drinking water treatment process." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008d/cochran.pdf.
Abstract:
Thesis (Ph. D.)--University of Alabama at Birmingham, 2008.Additional advisors: Robert A. Angus, Joe J. Gauthier, Jason T. Kirby, Robert W. Peters. Description based on contents viewed June 12, 2008; title from title screen. Includes bibliographical references (p. 85-87).
39
Dikinya, Oagile. "The effects of self-filtration on saturated hydraulic conductivity in sodic sandy soils." University of Western Australia. School of Earth and Geographical Sciences, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0051.
Abstract:
[Truncated abstract] Self-filtration is here defined as particle detachment and re-deposition causing re-arrangement of the particles and therefore pore space which affects water flow in soil by decreasing hydraulic conductivity. This is of particular important in soils which are susceptible to structural breakdown. The objective of this thesis was to examine the dynamics of the self-filtration process in sodic sandy soils as affected by ionic strength and soil solution composition. The temporal changes of hydraulic conductivity and the elution of fine particles from soil columns were used as the main criteria to assess selffiltration. Two porous media exhibiting significantly different structural cohesion were examined, one a loamy sand (Balkuling soil) from agricultural land use and the second a mining residue from mineral sands operations . . . The effects of the composition of mixed calcium (Ca) and sodium (Na) ions in solution (sodium adsorption ratio (SAR)) on the exchange behaviour and saturated hydraulic conductivity were examined by carrying out batch binary exchange and saturated column transport experiments. A strong preference for Ca2+ ions in the exchange complex was observed for both soils. Generally K/Ko was found to decrease with increasing sodium adsorption ratio with the more structured Balkuling soil maintaining K/Ko for SARs 3 and 5 at an electrolyte concentration of 100 mmol/L. However measurements at the critical threshold and turbidity concentrations at a SAR of 15 revealed structural breakdown of the pore matrix system attributed to various extents of slaking, swelling, dispersion and decreases of pore radii as a result of selffiltration during leaching. These experiments illustrate the wide range of complex interactions involving clay mineralogy, solution composition and structural factors which can influence the extent of mobilization, transport and re-deposition of colloidal particles during the leaching process in soil profiles.
40
Coulibaly, Bintou C. "Fasso Town: A Place Where Immigrants Can Reinvent Themselves." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1583998471845665.
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Anggraini, Agustina Kiky [Verfasser], and F. [Akademischer Betreuer] Nestmann. "Optimization of Slow Sand Filtration Design by Understanding the Influence of Operating Variables on the Physical Removal Mechanisms / Agustina Kiky Anggraini ; Betreuer: F. Nestmann." Karlsruhe : KIT-Bibliothek, 2018. http://d-nb.info/1159637512/34.
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Westensee, Dirk Karl. "Post-treatment technologies for integrated algal pond systems." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1018180.
Abstract:
Integrated Algae Pond Systems (IAPS) are a derivation of the Oswald designed Algal Integrated Wastewater Pond Systems (AIWPS®) and combine the use of anaerobic and aerobic bioprocesses to effect wastewater treatment. IAPS technology was introduced to South Africa in 1996 and a pilot plant designed and commissioned at the Belmont Valley WWTW in Grahamstown. The system has been in continual use since implementation and affords a secondarily treated water for reclamation according to its design specifications which most closely resemble those of the AIWPS® Advanced Secondary Process developed by Oswald. As a consequence, and as might be expected, while the technology performed well and delivered a final effluent superior to most pond systems deployed in South Africa it was unable to meet The Department of Water Affairs General Standard for nutrient removal and effluent discharge. The work described in this thesis involved the design, construction, and evaluation of several tertiary treatment units (TTU') for incorporation into the IAPS process design. Included were; Maturation Ponds (MP), Slow Sand Filter (SSF) and Rock Filters (RF). Three MP's were constructed in series with a 12 day retention time and operated in parallel with a two-layered SSF and a three-stage RF. Water quality of the effluent emerging from each of these TTU's was monitored over a 10 month period. Significant decreases in the chemical oxygen demand (COD), ammonium-N, phosphate-P, nitrate-N, faecal coliforms (FC) and total coliforms (TC) were achieved by these TTU's. On average, throughout the testing period, water quality was within the statutory limit for discharge to a water course that is not a listed water course, with the exception of the total suspended solids (TSS). The RF was determined as the most suitable TTU for commercial use due to production of a better quality water, smaller footprint, lower construction costs and less maintenance required. From the results of this investigation it is concluded that commercial deployment of IAPS for the treatment of municipal sewage requires the inclusion of a suitable TTU. Furthermore, and based on the findings presented, RF appears most appropriate to ensure that quality of the final effluent meets the standard for discharge.
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CAMPLESI, Daniela Cristina Fonseca. "Desempenho da Tecnologia de Filtração em Múltiplas Etapas (FiME) no Tratamento de Águas de Abastecimento em Escala Piloto." Universidade Federal de Goiás, 2009. http://repositorio.bc.ufg.br/tede/handle/tde/637.
Abstract:
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dissertacao daniela camplesi.pdf: 1230668 bytes, checksum: 56ed1f54e5e43d735ad2b69bff069adc (MD5)
Previous issue date: 2009-12-18The present work has evaluated the efficiency of an MSF system for treating supplying water on a pilot scale. A MSF pilot plant was located in the Water Treatment Station (WTS) area in Goianápolis- GO and fed by Sozinha stream. The plant was comprised of a dynamic prefilter (DPF) and a vertical upflowing pre-filter (VUF) in layers, both of them with different granular compositions; a slow sand filter (SSF); and a slow sand filter with activated carbon (SSFAC), which was called SEQ. 1. The second sequence of the trial, SEQ. 2, was comprised of a dynamic pre-filter (DPF) and a slow sand filter (SSF-2). The filtration rates in use were 24 and 48 m3/m2 a day for DPF, 12 e 24 m3/m2. day for APF; 3 e 6 m3/m2. day for SSF and SSFAC. The efficiency was evaluated by analyzing turbidity, apparent color, total suspended solids (TSS), as well as total thermo tolerant coliforms. The following items were evaluated: the filtration rates ranging effect onto the MSF unit trial system efficiencies; the MSF system efficiency comparison to the WTS complete cycling treatment; and the correlations between turbidity, color, and coliforms removals and the TSS removals. The results obtained from the trials have shown that DPF and VUF are important units for microorganisms and solid particles retaining, for it prepares the effluent in order to submit it into slow filtration. They have also shown that they make it possible for the roughing filtration to last longer. Generally put, it presents that the slow filters are significantly and above 90% efficient in removing TSS, color and turbidity, and 99% efficient in removing total coliforms and thermotolerant coliforms in all roughing filtration. After comparing the quality of both the water produced by MSF and the one by the complete cycling WTS, it was noticed that MSF produces water with quality similar to the complete cycling WTS. The range for the filtration rates has had significant influence only in the removal efficiencies of color and turbidity. There isn t correlation among the removals of the parameters color, turbidity, TSS and coliforms but for the correlation among apparent color and true color. The experiment results suggest that MSF technology, when suitably operated, it is a viable system for the treatment of supplying water and produced water with low levels of color, turbidity, TSS and coliforms is that 40% of the samples, provided drinking water under conditions compatible to those established by Decree 518/2004 of the Ministry of Health (BRAZIL, 2004) for human consumption
O presente trabalho avaliou a eficiência de um sistema de FiME no tratamento de águas de abastecimento em escala piloto. A instalação piloto FiME, localizada na área da Estação de Tratamento de Água (ETA) de Goianápolis, GO e alimentada pelo Ribeirão Sozinha, era composta de um pré-filtro dinâmico (PFD), um pré-filtro com escoamento vertical ascendente (PFA) em camadas, ambos com composições granulométricas diferenciadas, um filtro lento de areia (FLA) e um filtro lento de areia com carvão ativado (FLAC) e foi denominada SEQ 1. A SEQ 2 do experimento era constituída de um pré-filtro dinâmico (PFD) e um filtro lento de areia (FLA-2). As taxas de filtração utilizadas foram 24 e 48 m3/m2. dia para PFD, 12 e 24 m3/m2. dia para PFA, 3 e 6 m3/m2. dia para FLA e FLAC. A eficiência foi avaliada por meio das análises de turbidez, cor aparente, sólidos suspensos totais (SST) e coliformes totais e termotolerantes. Foi avaliado também o efeito da variação das taxas de filtração nas eficiências das unidades do sistema FiME, a comparação da eficiência do sistema FiME com o tratamento de ciclo completo da ETA e as correlações entre as remoções de turbidez, cor, coliformes e a remoção de SST. Os resultados obtidos nos experimentos demonstraram que o PFD e PFA são unidades importantes para a retenção de partículas sólidas e microorganismos, preparando o afluente para ser submetido à filtração lenta e possibilitam maior duração das carreiras de filtração. De maneira geral, os filtros lentos apresentaram eficiências significativas e superiores a 90% para remoção de cor, turbidez, SST e 99,9% de eficiência para remoção de coliformes totais e termotolerantes em praticamente todas as carreiras de filtração. Quando comparada a qualidade da água produzida pelo sistema FiME com a ETA de ciclo completo, verificou-se que a FiME produz água com qualidade similar à ETA de ciclo completo. As variações das taxas de filtração influenciaram significativamente nas eficiências de remoção de cor e turbidez. Não há correlação entre as remoções dos parâmetros cor, turbidez, SST e coliformes mas há correlação para cor aparente e cor verdadeira. Os resultados obtidos nos experimentos sugerem que a tecnologia de FiME, quando operada adequadamente, é um sistema viável para o tratamento de águas de abastecimento e produziu água com baixos teores de cor, turbidez, SST e coliformes sendo que em 40% das amostras analisadas, proveu água potável em condições compatíveis às estabelecidas pela Portaria 518/2004 do Ministério da Saúde (BRASIL, 2004) para consumo humano
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Gobbi, Sidinei Antonio. "Remoção de ovos de helmintos de esgotos secundários, por meio de filtros rápidos de areia, carvão antracitoso e zeólito para reúso agrícola e urbano não potável." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-11082010-104518/.
Abstract:
A presença de ovos de helmintos é um dos principais problemas do reúso de esgotos tratados na irrigação agrícola e no reúso urbano não potável. Isso porque pode haver contaminação dos trabalhadores que manipulam a água de reúso e da população consumidora. Os ovos de helmintos não são removidos com eficiência por meio de operações e processos unitários convencionais. Esses processos não possibilitam a remoção de ovos de helmintos a níveis estabelecidos pelas diretrizes da Organização Mundial da Saúde (OMS) para o reúso. Avaliar a filtração até a gravidade, como unidade complementar de tratamento, para a remoção de ovos de helmintos é o objetivo desta pesquisa. Como os efluentes de estações de tratamento de esgotos locais apresentam concentrações muito variáveis de ovos de helmintos, foi utilizada uma solução sintética de ovos padronizados Ascaris suum. A solução sintética preparada com o uso dos ovos padronizados foi usada na determinação dos parâmetros de operação do processo de filtração. Após esses ensaios, foram realizados testes em escala piloto com esgoto tratado, objetivando o estudo da influência da matéria orgânica, dos sólidos e de outros interferentes do processo. Os experimentos com solução sintética foram desenvolvidos nos laboratórios do Centro Internacional de Referência em Reúso de Água (CIRRA), da Escola Politécnica da USP. As experiências com esgoto tratado foram realizadas na ETE do ABC, da SABESP. Os resultados mostraram que as três colunas de filtração foram muito eficientes na remoção dos ovos de helmintos, produzindo um efluente com concentração final inferior a 1 ovo/l. Além disso, a filtração possibilitou a remoção de sólidos suspensos totais, turbidez, cor e material orgânico particulado, resultando em um efluente com grande potencial para ser reusado na irrigação agrícola, bem como no reúso urbano não potável.Helminth eggs are one of the major problems regarding the reuse of treated sewage in agriculture and non-potable urban irrigation since both workers who handle the effluent and the consumer population might become contaminated. Helminth eggs are not efficiently removed by conventional unit operations and processes, which do not allow the removal of helminth eggs at levels established by the World Health Organization guidelines. The objective of this research is to assess the gravity filtration as an additional unit of treatment for the removal of helminth eggs. Since local effluent sewage treatment stations have highly variable concentrations of helminth eggs, a synthetic solution of standardized Ascaris suum was used. The synthetic solution prepared with standardized eggs was used to determine the operating parameters of the filtration process. Following the trials, pilot scale tests with treated sewage were conducted aimed at evaluating the influence of organic materials, solids, among other materials which might interfere in the process. Experiments with synthetic solution were performed in the laboratory of the International Center of Water Reuse - CIRRA, at the Polytechnic School of the University of São Paulo. Experiments with treated sewage were performed at ETE - ABC, SABESP. The results showed that the three filtration columns were very efficient in removing helminth eggs, which resulted in an effluent with a final concentration of < 1 egg/L. In addition, the filtration allowed the removal of total suspended solids, turbidity, color, and particulate organic material, resulting in an effluent with great potential to be reused in irrigation as well as in non-potable urban reuse.
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BARTON, JOHN M. H. "EFFECT OF MEDIA GRAIN SHAPE ON PHYSICAL CAPTURE OF PARTICLES IN A FILTER BED." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1092931427.
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Saldanha, João Rodrigo. "Avaliação do desempenho de uma estação de tratamento de água com sistema de dupla filtração, em escala real." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-24012017-152630/.
Abstract:
A tecnologia de tratamento com dupla filtração encontra-se em estágio relativamente elevado de desenvolvimento, porém, ainda são poucos os dados de operação em escala real. Este trabalho teve como objetivo avaliar um sistema de dupla filtração em escala real (ETA2) para tratamento de água, do serviço autônomo de água e esgoto da cidade de São Carlos - SP, que trata água bruta proveniente do Ribeirão do Feijão e é constituída de três unidades de filtração cada uma contendo um filtro ascendente e um descendente. Em uma primeira etapa foram levantadas as medidas das unidades de dupla filtração, caracterizado o material filtrante e avaliadas as condições operacionais da ETA 2. Posteriormente, foi estudada a situação geral da ETA por meio de diversos parâmetros (turbidez, pH, expansão da areia na lavagem, contagem de partículas, de coliformes totais e Escherichia. coli), para verificar os principais problemas. Em seguida, realizou-se uma comparação da ETA2 com uma Instalação Piloto de Dupla Filtração. Este trabalho permitiu concluir principalmente que: i) devido às baixas taxas de filtração de unidades filtrantes da ETA2, excessivas dosagens de coagulante e falta de controle de lavagens, geralmente foi baixa a produção efetiva de água (em torno de 90%); ii) o desempenho, algumas vezes insatisfatório das unidades de filtração ascendente e descendente, deveu-se principalmente à ineficiência da mistura de coagulante na água bruta, falta de areia nos filtros ascendentes e à diferença de granulometria nos filtros descendentes; iii) o desenvolvimento da perda de carga nos filtros ascendentes da ETA2 foi mais acentuado na Instalação Piloto devido à mistura de seus materiais filtrantes.Water treatment by means of a double filtration system is in a relatively high stage of development, however, there are still few data on real scale operations. The aim of this work was to evaluate a double filtration system in a real scale (ETA2) for the treatment of water, of the autonomous service of water and sewer of the city of São Carlos - SP, which treats water from the Ribeirão do Feijão (name of a local river), and is constituted of three filtration units, each a contain a direct up-flow sand filter, and a rapid filter. In the first stage, the sand of the filters was characterized, and the operational conditions of the ETA2 were evaluated. Next, the general situation of the ETA was studied by means of several parameters (turbidity, pH, expansion of the sand during washing process, counting of particles, total coliforms and Escherichia coli), in a order to detect the main problems. Finally, a confrontation between the ETA2 an a double filtration pilot Plant was carried through. This study made infer that: I) due to the low filtration rates of the ETA2`s filtration units, excessive doses of coagulant and lack of control of the washings, the actual production of water was low (around 90%); ii) the sometimes insufficient performance of the direct up-flow sand filtration and rapid filtration systems was mainly caused by an inefficient mixing of the coagulant with the natural water, lack of sand in direct up-flow filters; iii) the building up of the lossof cargo in the direct up-flow san filtration in filters of the ETA2 was more accentuated than in the Pilot Plant due to the mixture of the filtration materials.
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Nývltová, Barbora. "Posouzení účinnosti úpravny pitné vody prostřednictvím ekotoxikologických testů a screeningové analýzy." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-316248.
Abstract:
The quality of raw water is deteriorating with the continuous increase in environmental pollution. Raw water is being modified to drinking water by technological processes, and it is therefore necessary to put increased demands on the efficiency of these technological processes and their possible innovation. Due to the fact that raw water is contaminated with different types of pollutants, it is necessary to continuously control the drinking water supplied to the public distribution network in order to ensure its quality. Drinking water treatment is still unable to treat the raw water perfectly, its pollution is only reduced to acceptable standards. For this reason, it is indispensable that the quality of drinking water is being checked regularly and at the same time the efficiency of individual technological processes of drinking water treatment is assessed. This includes screening analysis or eventually ecotoxicological tests. The thesis focuses on the efficiency of technological processes of drinking water treatment. Within the experimental part, samples of raw water and samples of water after each separation stage have been collected at the drinking water treatment plant in the Czech Republic. These samples have been subjected to ecotoxicological tests and screening analysis. Based on the ecotoxicological tests carried out on Thamnocephalus platyurus, Lemna minor and Vibrio fischeri, we can assume the emergence of harmful chlorinated by-products, resulting to nearly 100% mortality in T. platyurus. The results of the screening analysis carried out indicate, after the extraction of specimens by the SPE method using HPLC/MS, that the most effective method for the removal of hormonal substances is ozonization.
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Carré, Erwan. "Qualité biologique des eaux usées traitées en vue de la réutilisation." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEM018/document.
Abstract:
La réutilisation des eaux usées traitées (REUT) constitue une ressource alternative pérenne et à fort potentiel notamment pour les régions soumises à un stress hydrique. L’objectif général de cette thèse est de définir les conditions nécessaires pour garantir la fiabilité d’une filière de traitement tertiaire pour la réutilisation. La première partie s’intéresse aux limites des méthodes de dénombrement des microorganismes indicateurs couramment employées, notamment en lien avec la contamination particulaire des effluents. Les résultats indiquent qu’il existe un risque de sous-estimation par ces méthodes pour de fortes charges en matières en suspension.La désinfection par rayonnement ultraviolet (UV) est souvent employée pour garantir la qualité sanitaire de l’eau distribuée. La deuxième partie de cette thèse vise à comprendre les mécanismes pouvant affecter l’efficacité des UV. Une corrélation linéaire a pu être mise en évidence entre la contamination particulaire des effluents à traiter et la baisse d’efficacité de la désinfection UV, caractérisée d’une part par la diminution de la constante d’inactivation des microorganismes exposés aux UV et d’autre part par le risque d’apparition d’un effet de traîne (fraction de microorganismes insensibles aux UV).La mise en place d’un prétraitement par filtration s’avère donc nécessaire en amont de la désinfection UV. La troisième partie de cette thèse a permis de définir les paramètres opératoires les plus adaptés à l’effluent. Enfin, le contrôle de la qualité sur l’ensemble de la filière est envisagé, avec notamment la démonstration de faisabilité d’un système de surveillance en continu basé sur la spectrométrie UV/VisibleWastewater reclamation is an ongoing and promising alternative resource in a context of water stress. In particular, this is a major issue in the Mediterranean region, and its effects tend to be intensified by global warming. The main objective of this PhD thesis is to define the conditions for ensuring the reliability of a tertiary treatment chain for wastewater reclamation. The first part deals with the limits of the methods used in routine for the enumeration of indicator microorganisms, in relation with particulate contamination. The results indicate that there is a risk of underestimation by these methods for high loads of suspended matter.Ultraviolet (UV) disinfection has been used for years to ensure the biological safety of reclaimed water. The second part of this work aims to understand the mechanisms which may affect the efficiency of UV disinfection. A linear relationship has been observed between the particulate contamination of the effluents to be treated and the disinfection efficiency loss, featured on one hand by the decrease of the inactivation constant of the microorganisms and on the other hand by the risk of tailing (UV-resistant fraction among the microorganisms).The implementation of a pre-filtration is thus necessary before UV disinfection. The third part of this work enabled to identify the filtration parameters suited for the effluents to be treated. Finally, quality control on the whole chain is considered, in particular with the demonstration of feasibility of a continuous control system based on UV/Visible spectrometry
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Marrara, Danilo Aparecido Faveri. "Filtração lenta em areia, manta não tecida e carvão ativado como pós-tratamento de efluentes domesticos e reuso." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257794.
Abstract:
Orientador: Jose Euclides Stipp PaternianiDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
Made available in DSpace on 2018-08-06T17:36:20Z (GMT). No. of bitstreams: 1 Marrara_DaniloAparecidoFaveri_M.pdf: 739626 bytes, checksum: a356e874839131fd6c648e10f03c0b05 (MD5) Previous issue date: 2005
Resumo: A filtração lenta é uma alternativa viável para regiões rurais afastadas dos grandes centros urbanos que necessitam de um sistema de tratamento de água de baixo custo de implantação, assim, presente trabalho avaliou a eficiência e o desempenho da filtração lenta em uma instalação piloto de filtração em areia e manta não tecida, e carvão ativado, precedida de um pré-filtro em pedregulho para tratamento de efluente de um sistema composto um de reator anaeróbio compartimentado e de leitos cultivados (wetlands) para tratamento de esgoto doméstico. Ênfases específicas foram dadas na avaliação da Filtração Lenta com meio filtrante de areia e manta não tecida e meio filtrante de areia com camada de carvão ativado granular e manta não tecida. Para uma taxa de filtração média de 3 m3/m2.dia, obteve-se uma eficiência média na remoção de sólidos em suspensão de 36,2% para o filtro lento de carvão e areia e manta não tecida e 28,2% para o filtro lento de areia e manta não tecida. A eficiência na remoção de turbidez foi de 43,2% no filtro de carvão e areia e manta não tecida e 33,2% no filtro de areia e manta não tecida. Para a cor obteve-se uma eficiência média de 39,3% para o filtro lento com camada de carvão e areia e manta não tecida e 26,0% para o filtro lento de areia e manta não tecida. A eficiência média na remoção de coliformes totais foi de 74,6% para o filtro lento de carvão e areia e manta não tecida e de 57,6% para o filtro lento de areia e manta não tecida. A remoção média de E.coli foi de 72,7% para o filtro lento de carvão e areia e manta não tecida e de 70,8% para o filtro lento de areia e manta não tecida. Devido à simplicidade de construção e operação, o filtro lento de carvão e areia e manta não tecida pode ser aplicado para tratamento de efluentes domésticos em pequenas comunidades bem como pode ser utilizado para melhorar a qualidade de um efluente a ser lançado em corpos d¿água ou se utilizar desta tecnologia simples para tratar água para fins de reuso
Abstract: The slow sand filtration is a viable economic alternative for small communities moved away from the great urban centers. This work evaluated the efficiency of a slow filter with sand layer, activated carbon and non-woven synthetic fabric, compared with a slow filter of sand and non-woven synthetic fabric to treat constructed wetland effluent. The results had shown the removal of 74,6% of total coliforms for the slow sand filter with activated carbon and 57.6% for the slow sand filter without activated carbon. The solid reduction was 36,2% for the filter with activated carbon and 26.2% for the filter without activated carbon. For the turbidity, the reduction of 43,2% for the filter with activated carbon against 33,2% for the filter without activated carbon, and for color the filter with activated carbon got 39.3% of efficiency against 26,0% for the filter without activated carbon. Due to simplicity of construction and operation, the slow sand filter with activated carbon, sand and non-woven synthetic fabric can be applied for treatment of domestic sewer in small communities and can be used to improve the quality of an effluent to be launched in water or use this simple technology to water treatment and water reuse
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil
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Brinck, Nádia Cristina Pires. "Avaliação do tipo de material filtrante no comportamento hidráulico de filtros rápidos de camada profunda no tratamento de águas de abastecimento." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-01092009-160800/.
Abstract:
Neste projeto de pesquisa avaliou-se a etapa de filtração no processo de tratamento de água para abastecimento público. Para isto, foi utilizado um sistema de filtração piloto composto por quatro filtros rápidos por gravidade de camada profunda. Os filtros piloto foram alimentados com água decantada da Estação de Tratamento de Água Rio Grande, e operados com taxa de filtração de 500 m3/m2/dia. A concepção dos filtros variou em termos de material filtrante (areia e antracito), diâmetro dos grãos e altura do leito. Os filtros foram avaliados em termos de turbidez, contagem de partículas, evolução de perda de carga e velocidade ascensional de água de lavagem. Na Etapa 1, operando-se filtros de areia e antracito com diferentes diâmetros, o filtro de antracito com 1,3 mm de diâmetro e 120 cm de altura apresentou melhor comportamento no tocante aos parâmetros avaliados. Na etapa 2, comparando-se filtros de areia e de antracito com mesmo diâmetro (1,3 mm) e altura de leito (120 cm), mais uma vez o filtro de antracito foi superior. Acredita-se que os índices físicos justifiquem esse comportamento. Na Etapa 3, conclui-se que o aumento de altura de leito dos filtros de areia (1,3 mm) e antracito (1,3 mm) de 120 cm para 160 cm foi benéfico para ambos os materiais filtrantes em termos de qualidade do efluente, mas muito mais significativo para o antracito, e não se observou alteração de comportamento no tocante à evolução de perda de carga. Com o ensaio de fluidificação e expansão do leito filtrante, conclui-se que, considerando-se o mesmo tempo de duração da lavagem e a mesma expansão do leito, o filtro de antracito possibilitou a utilização de menor velocidade ascensional de água de lavagem, que representa grande economia com relação aos custos do sistema de lavagem. Assim, em todos os aspectos estudados, o uso de antracito (1,3 mm) como material filtrante para filtros rápidos por gravidade de camada profunda se mostrou mais vantajoso.This project researched the filtration stage in the water treatment process for public use. The research used a pilot filtration system based on four rapid gravity depth bed filters, with a filtration rate of 500m3/m2/dia. The water used in the experiment came from sedimentation tank of the Rio Grande water treatment facility. During the experimental phase the filters were loaded with different depth, used different filter media (sand and anthracite) and used grain with different effective size. The filters were evaluated in terms of turbidity, particle count, head loss and superficial velocity of backwashing water. In the first part of the study, when analyzing the results of filters loaded to a depth of 120 cm using both sand and anthracite with different size, the anthracite filter with effective size of 1.3 mm was the one with the best results. In the second part of the study, when comparing anthracite and sand with same the effective size, the anthracite also presented better results. Finally when increasing the depth of the filter, both sand and anthracite filters showed improved performance in terms of effluent quality, but anthracite filters kept outperforming sand filters. In both case, there were no evidences of changing in the head loss development. When performing fluidization and expansion experiments, considering the same backwashing cycle time and expansion of filter media, the anthracite filter allowed lower superficial velocity which represents relevant economies in the washing system costs. Therefore the use of anthracite (1.3mm) as a filter medium for rapid gravity depth bed filters is recommended.