Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esse texto trata do problema de um fluido contaminado escoando por um meio poroso, tratando os componentes na mistura como meios contínuos. Na primeira parte, desenvolvemos a teoria de misturas de meios contínuos e discutimos equações da continuidade, momento linear e momento angular. A seguir, descrevemos o problema em detalhe e fazemos hipóteses para simplificar o escoamento. Aplicamos as equações encontradas anteriormente para encontrarmos um sistema de equações diferenciais parciais. Desse ponto em diante, o problema se torna quase puramente matemático. Discutimos o caso insaturado, e depois a saturação do meio poroso. Finalmente, adicionamos um contaminante à mistura e, em seguida, N contaminantes. / This text treats the problem of a contaminated fluid flowing through a porous medium, treating the components in the mixture as continuum media. In the first part, we develop the continuum mixture theory and discuss equations for continuity, linear momentum and angular momentum. Next, we describe the problem in detail and make hypotheses to simplify the flow. We apply the equations found previously to a system of partial diferential equations. From then on, the problem becomes almost purely mathematical. We discuss the unsaturated case, then the saturation of the porous medium. Finally, we add a contaminant to the mixture and, then, N contaminants.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esse texto trata do problema de um fluido contaminado escoando por um meio poroso, tratando os componentes na mistura como meios contínuos. Na primeira parte, desenvolvemos a teoria de misturas de meios contínuos e discutimos equações da continuidade, momento linear e momento angular. A seguir, descrevemos o problema em detalhe e fazemos hipóteses para simplificar o escoamento. Aplicamos as equações encontradas anteriormente para encontrarmos um sistema de equações diferenciais parciais. Desse ponto em diante, o problema se torna quase puramente matemático. Discutimos o caso insaturado, e depois a saturação do meio poroso. Finalmente, adicionamos um contaminante à mistura e, em seguida, N contaminantes. / This text treats the problem of a contaminated fluid flowing through a porous medium, treating the components in the mixture as continuum media. In the first part, we develop the continuum mixture theory and discuss equations for continuity, linear momentum and angular momentum. Next, we describe the problem in detail and make hypotheses to simplify the flow. We apply the equations found previously to a system of partial diferential equations. From then on, the problem becomes almost purely mathematical. We discuss the unsaturated case, then the saturation of the porous medium. Finally, we add a contaminant to the mixture and, then, N contaminants.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Irreplaceable element for life, phosphorus is the main component of apatite, a mineral present in phosphate rock. The increasing in agriculture productivity would not be possible without the use of fertilizers. However, being a non-renewable resource, the phosphorus is susceptible to depletion. The exploitation of economically mineable deposits of phosphate ore leads to large losses of phosphorus in the stage of processing. In contrast, the demand for fertilizers in the country only increases. Currently, more than half of world production of phosphate concentrate is produced by flotation. The column flotation has been adequate to the processing of complex and low grades ores, that is the case of Brazilian deposits, and also fine size ranges. However, difficulty in concentrating ores of igneous origin may be aggravated in the presence of dissolved ions in process water used in flotation, since the recirculated water increases the ionic concentration. According to the literature, the process of concentration of apatite is strongly affected by the presence of ionic species, since they interact with the surface of apatite particles by changing the efficiency of the flotation process. Thus, the aim of this work was to evaluate the influence of water contaminated with ions F-, Ca2 +, Mg2 + and PO43- provides in the performance of apatite flotation or, in other words, in recovery, P2O5 content and selectivity of the process, to the coarse and fine ores carried out in a flotation column. And through central composite design (CCD), the influence of these ions in the apatite recovery and P2O5 content for low and high concentrations of contaminants. The results showed that the individual effect of each ion studied provided a substantial decrease in recovery, with different sensitivity to the size ranges studied. The most expressive decreases in apatite recovery are related to contaminants calcium and phosphate, where the first had a maximum reduction in the recovery of 58 and 51% for the coarse and fine, respectively, since the calcium consume the collector, reducing the amount available for the apatite collection. Phosphate confirms its strong depressant effect on the apatite particles, since for the coarse particles, there was a reduction in maximum recovery of 55% and 59% for the fines. For the contaminant magnesium, it is clear the critical effect on the process selectivity, related to the gangue minerals Fe2O3 and SiO2, since P2O5 content, in the presence of this ion, suffered a considerable decrease (up to 8 percentage points), independent of particle size. Magnesium, that also react with the collector, was responsible for the sharp increase in the consumption of NaOH, used to adjust the pulp pH, reaching up to 4 times higher compared to the standard test. The influence of fluoride ion represented an increase in the ratio of selectivity P2O5/SiO2, especially for the fine material, indicating a possible depressing effect on the silicate gangue. For the CCD, carried out at low contaminants concentrations, it is clear the interactions between calcium and magnesium with phosphate, contributing to the increase in the recovery, and between magnesium and fluoride, which contributed to the increase in the P2O5 content. This behavior is probably due to the fact that these ions form insoluble compounds among them, removing these ionic species from the system. As for the CCD performed to high contaminants concentrations, all the flotation tests resulted in very low values of recovery and grade. This fact may be associated with the formation of colloidal precipitates in large quantities, leading to indiscriminate coating of the mineral particles present, including apatite, preventing the reagents action. / Elemento insubstituível para a vida, o fósforo constitui o principal componente da apatita, mineral presente na rocha fosfática. O crescente aumento da produtividade na agricultura não seria possível sem o uso dos fertilizantes. Entretanto, por ser um recurso não-renovável, o fósforo está suscetível ao esgotamento. A exploração dos depósitos economicamente lavráveis de minério fosfático leva a grandes perdas de fósforo na etapa de beneficiamento. Contrariamente, a demanda por fertilizantes no país só aumenta. Atualmente, mais da metade da produção mundial de concentrado fosfático é produzido por flotação. A coluna de flotação tem se mostrado adequada ao beneficiamento de minérios complexos e de baixos teores, caso das reservas brasileiras, e também de granulometria mais fina. No entanto, a dificuldade em concentrar minérios de origem ígnea pode ser agravada quando em presença de íons dissolvidos na água de processo empregada na flotação, uma vez que a água recirculada aumenta a concentração iônica presente. De acordo com a literatura, o processo de concentração da apatita é fortemente afetado pela presença de espécies iônicas, uma vez que estas interagem com a superfície da partícula de apatita alterando a eficiência do processo de flotação. Sendo assim, este trabalho teve por objetivo avaliar a influência que a água contaminada com os íons F-, Ca2+, Mg2+ e PO43- acarreta no desempenho da flotação em coluna de apatita, ou seja, na recuperação, teor de P2O5 e seletividade do processo, para minério de granulometria grossa e fina, e, por meio de planejamento do tipo composto central (PCC), a influência destes mesmos íons na recuperação e teor de P2O5 para baixas e altas concentrações de contaminantes. Os resultados obtidos permitem concluir que o efeito individual de cada íon estudado proporcionou uma substancial queda na recuperação, apresentando diferente sensibilidade em relação à faixa granulométrica empregada. Os resultados mais expressivos de queda na recuperação são referentes aos contaminantes cálcio e fosfato, onde o primeiro teve uma redução máxima na recuperação de 58 e 51% para o material grosso e fino, respectivamente, em virtude do cálcio consumir o coletor, reduzindo a quantidade disponível para a coleta de apatita. O fosfato confirma seu forte efeito depressor sobre as partículas de apatita, visto que, para os grossos, houve uma redução máxima na recuperação de 55% e de 59% para os finos. Para o contaminante magnésio, fica claro o efeito crítico na seletividade do processo, em relação aos minerais de ganga Fe2O3 e SiO2, uma vez que o teor de P2O5, quando em presença deste íon, sofreu uma considerável queda (até 8 pontos percentuais), independente do tamanho de partícula. O magnésio, além de reagir também com o coletor, foi responsável pelo aumento acentuado no consumo de NaOH, utilizado para regular o pH da polpa, chegando a ser 4 vezes maior, comparado ao teste branco. A influência do íon fluoreto representou um aumento na razão de seletividade P2O5/SiO2, principalmente para o material fino, indicando possível efeito depressor sobre a ganga silicatada. Para o PCC realizado a baixas concentrações de contaminantes, fica evidenciado as interações entre os cátions cálcio e magnésio com fosfato, contribuindo para o aumento da resposta recuperação, e entre magnésio e fluoreto, onde colaborou para o aumento da resposta teor. Este comportamento, provavelmente, é devido ao fato destes íons formarem compostos insolúveis entre si, sequestrando estas espécies iônicas do sistema. Já para o PCC realizado a altas concentrações de contaminantes, todos os ensaios de flotação resultaram em valores extremamente baixos de recuperação e teor. Este fato pode estar associado à formação de precipitados coloidais em grande quantidade, levando a recobrir indiscriminadamente as partículas minerais presentes, inclusive a apatita, impedindo a ação dos reagentes. / Mestre em Engenharia Química

[pt] A água potável não existe mais em abundância. É preocupante verificar que o desperdício e a contaminação dos recursos hídricos ainda sejam práticas recorrentes, mesmo diante de evidências pessimistas acerca de sua disponibilidade, como observado no local escolhido para o desenvolvimento desta pesquisa. Portanto, este trabalho tem como objetivo apresentar soluções para evitar a contaminação do sistema de abastecimento, recomendar equipamentos de saneamento, sugerir um esquema de drenagem que não favoreça a proliferação de vetores de doenças, propor uma estratégia para o manejo adequado dos animais domésticos e garantir o fornecimento de água verdadeiramente potável na vila de Tanahbala, na Indonésia. O desenho metodológico está alinhado aos pressupostos da pesquisa exploratória, com a apresentação do diagnóstico local, para posterior análise quantitativa por meio da aplicação de um software de modelagem matemática, denominado Modflow 2000, versão 4.2.0.1.5.1. A ferramenta foi utilizada para visualizar o fluxo dos contaminantes no lençol freático e estimar a concentração dessas substâncias na fonte de abastecimento da vila, para posterior apresentação das sugestões de melhoria. Como resultado do diagnóstico local e dos níveis numéricos de contaminação, foi possível observar que as causas desses problemas estavam ligadas ao esgoto doméstico, à criação desordenada de animais e à proximidade de um cemitério. Sugeriu-se então algumas soluções como a realocação dos poços para captação de água, a construção de cisternas para captar água da chuva, a utilização de liners e de uma camada de geomembrana, o manejo dos dejetos da criação de animais, drenagem e soluções de saneamento. / [en] Potable water has become increasingly scarce. It is no longer an infinitely renewable resource as we once thought it was. However, it is not unusual to see hydric resources being wasted or contaminated – despite all the pessimistic forecasts regarding its availability for the future generations. Actually, lack of water is not a far-fetched problem anymore. Around 1.6 billion people rely on insufficient hydric resources. By 2020, this number will double: there will be about 3 billion people with insufficient access to drinking water (Boff, 2005). The central theme of the present research deals with the problems provoked by an inefficient management of hydric resources. Its aim is to provide alternatives for managing water in the small and remote village of Tanahbala, in Indonesia. In this distant town, solutions which might be feasible elsewhere do not always prove to be possible. In order to provide potable water for the villagers in Tanahbala, it is crucial to overcome three main obstacles: 1) the inappropriate disposal of domestic sewage; 2) the lack of livestock management; and 3) the contamination provoked by a neighboring cemetery. So as to address these problems, the present study has pointed out a few measures, such as the replacement of water wells, the construction of tanks for catching and storing rainwater, the use of liners and a layer of geomembrane, the appropriate management of the animals excrement, as well as many other sanitary solutions. All these recommendations attempt to meet the village s needs without requiring a sophisticated infrastructure – which is not within the villagers reach at the present time. According to data from the World Health Organization (WHO) and UNICEF (2004), 1.1 billion people around the world do not have access to pure water. In the meantime, 2.6 billions do not live in areas with adequate sewage. Tanahbala, the place studied in this research, is just one more item in the apparently endless list of locations deprived from essential resources such as water. The troublesome water distribution and sewage treatment has a significant impact on mortality rates. All over the world, from four to six thousand children die everyday because of diseases associated to the lack of potable water or inadequate sewage treatment (WSSCC, 2011). In Indonesia, an impressive number of people live below the poverty line. In these lower social layers, the lack of potable water remains the most prominent health problem. The reasons behind this problem are the geographic aspects of Indonesia and the precariousness of the infrastructure used to distribute water. Quite differently from continental areas, Indonesia does not have the means to create a centralized water distribution system. Formed by thousands of islands, the country has to delegate to each one of them the management and the treatment of hydric resources. This is the reason why the population of Indonesia has suffered from a number of diarrheic diseases caused by contaminated water. No wonder diarrhea is still ranked among the ten main causes of deaths in Indonesia (WHO/ UNICEF, 2004). In fact, chronic infectious diarrhea has been detected in 66.7 per cent of the population. Based on this information, it is unavoidable to come to the conclusion that both, the treatment and the distribution of water in Indonesia, are quite far from the minimum security standards. Hence, it is clearly urgent to develop strategies to meet the population s needs, especially in the most distant islands, where potable water is still a far-fetched dream. In Indonesia, underground water is normally good from a microbiological viewpoint. The problem is that it is easily contaminated due to the emission of pollutants from homes, factories, plantations and even cemeteries. The present research focuses on specific types of water pollution: the contamination provoked by cemeteries, livestock and domestic sewage. The first part of this research has been developed by means of observing the region and collecting documents on the governmental database, so that the local characteristics could be thoroughly understood. The methodological design adopted, therefore, is in line with what is called exploratory research. In the engineering field, exploratory research is particularly useful when it is necessary to estimate the feasibility and the costs of a given project. The scope of the present research is precisely that: the aim is to provide a solid ground for the development of future research that might work on a more definite solution for the hydric resources in Tanahbala. First, this research presents a diagnosis of the local situation. Afterwards, a quantitative analysis is carried out with the help of a mathematical modeling software called Modflow 2000, version 4.2.0.1.5.1. This tool has been used to visualize the flow of contaminants in the underground water, as well as to estimate the concentration of substances in the water supply used by those who inhabit Tanahbala. In the end, this study recommends some improvements, without disregarding the limited resources and the precarious infrastructure available in the village. The inappropriate location of the cemetery and the careless management of livestock are not the only threats to the quality of the soil and the water in Tanahbala. The population is also used to bathing in public water sources, which certainly worsens the contamination problem. Raw sewage and animals surround the village, forming a single nucleus of contamination. The cemetery is on the left side of the entrance of the village. In addition to that, the well that supplies water to Tanahbala is dangerously close to the contaminated areas. Occasional earthquakes and tsunamis add chaos to a situation which is already quite precarious. In 2004, Indonesia was hit by a devastating tsunami, whose tragic effects were also felt in Tanahbala. A great part of the village lies on a type of soil that is mostly sandy, favoring the penetration of pollutants, due to its high permeability level. This characteristic increases considerably the risks of underground water contamination. The toxic fluids that come from the decomposition of corpses are the main cause of environmental pollution provoked by cemeteries. The crucial challenge is to stop them fluid from infiltrating into the soil and contaminating underground water. Liners are layers of low permeability formed by natural, artificial or a combination of both materials. The objective of these layers is to protect a given area from the infiltration of harmful fluids. One of its essential features is also the capacity of removing impurities. The use of liners is very common in sandy soils, where their efficiency is out of question. When used in this type of soil, the liners manage to reduce significantly the permeability level. Moreover, it is a low cost alternative, since it does not require the employment of higher technologies. The combination of these characteristics seems to point out the use of liners as the ideal option for protecting the inhabitants of Tanahbala against the hazardous substances that come from the cemetery. Geomembranes may also be an important ally. They are impermeable synthetic barriers, quite resistant from a physical and chemical point of view, and with low hydraulic conductivity. They are commonly used to stop leachate from migrating into the soil or underground water. Because they are susceptible to flaws, geomembranes should not be the only mechanism of protection. It is fundamental to rely on a more complete system of isolation. Taking into account the peculiarities of the Indonesian context, the present research recommends the use of a geomembrane and a liner formed by soil, cement and quicklime. Domestic sewage contains pathogens that cause several diseases, such as typhoid, infectious diarrhea and amebiasis. In Tanahbala, sewage is generally left on the soil, contributing to the dissemination of a wide variety of diseases. Besides, both superficial and underground water quality tends to be altered by this kind of contamination. The main consequences are a change in the color and in the smell of water, as well as a considerable reduction in the concentration of oxygen. The water pollution triggered by the lack of adequate sewage treatment is also harmful for the local environment, putting at stake the survival of animals and vegetation in the Indonesian village. The position of the wells in relation to the main points where contamination by sewage happens is also a fundamental aspect. In Tanahbala, the wells that provide drinking water for the houses are dangerously located downstream in relation to the places where contamination occurs. The solution is quite simple: repositioning these wells and placing them upstream is an essential step in order to improve the quality of the water available to the villagers. In addition, it is essential to construct a septic tank where sewage can be disposed and decomposed by anaerobic bacteria. The present research has used the Brazilian standards to suggest the measures for the Indonesian septic tank. However, in further studies, it is important to use local data to design the ideal system for the villagers in Tanahbala. Placing tanks to catch and store rainwater is an intelligent and inexpensive measure. With the high rainfall rates in Indonesia, this option seems to be very promising. As long as these tanks remain protected, the water stored by them is harmless. The choice of the material for the tank is also relevant. Cement lasts longer. However, if it is difficult to transport this material to Tanahbala, plastic tanks might be a better option. The construction of dungyards seems to be the most appropriate option for the population in Tanahbala. Besides presenting low costs, they are easily managed. The excrement kept in these dungyards remains there for 120 days. Throughout this period, organic matter becomes stable and the pathogens in it are deactivated. Composting is also a worthwhile alternative; after all, this process is able to reduce the bad smell and the proliferation of hazardous microorganisms. On top of that, composting turns useless ordure into a valuable commodity: manure, which is quite useful as a fertilizer. The main challenges regarding the use of composting have to do with handling three variables – humidity, aeration and temperature. The creation of an efficient draining system is essential and challenging at the same time. The first difficulty has to do with handling the rainwater that accumulates on the ground. When the draining system does not work properly, the population suffers from a number of problems, such as floods and diseases related to the uncontrolled accumulation of water: diarrhea, typhoid, leptospirosis and malaria are some of the illnesses that become widespread once draining is not efficient. In addition, humid soils provide a longer life for microorganisms. Thus, draining is an important tool when it comes to reducing the contamination of the soil by pathogens. In Tanahbala, specifically, it is recommended to adopt a microdraining system that combines three modalities: superficial, underground and vertical.Counting on appropriate equipment is not enough when the population is not aware of its environmental and sanitary responsibilities. Therefore, it is fundamental to raise people s awareness on the importance of adopting new hygiene habits and helping protect the environment.

Environmental pollution by pharmaceuticals is an issue of concern that is currently attracting attention around the world. Although environmental effects of pharmaceutical contaminants are not yet well documented, studies have shown that these substances may have the potential to disrupt the biotic component of an ecosystem. Particularly worrisome contaminants are the neuroactive pharmaceuticals which have the potentiality to induce behavioral modifications in non-target species. In the present study, I examined the effects of a benzodiazepine anxiolytic pharmaceutical (oxazepam) on the behavior of Atlantic salmon (Salmo salar) juveniles (fry). The hypothesis of this study was that oxazepam reduces the anxiety-like behavior of the Atlantic salmon juveniles. To test the hypothesis and assess the impact of oxazepam exposure on Atlantic salmons fry behavior, two different concentrations of this drug; a low-level (1.9 ug L-1) and a high-level concentration (1000 ug L-1) were used. Exposures lasted for 48 hours and afterwards, the fish were recorded to evaluate their behavioral responses. The results of this study reveal that oxazepam in a high concentration (1000 ug L-1 ) alters specific behavioral endpoints related to the fitness (feeding/predator avoidance) of Atlantic salmons fry. Individuals exposed to the high oxazepam concentration exhibited significant lower average speed and acceleration as well as they traveled a shorter mean distance compared to the unexposed (control) individuals. These findings confirm the hypothesis and show that psychotropic pharmaceutical contaminants modify animal behaviors, which can ultimately lead to ecological consequences. However, the concentration that generated behavioral effects in this study was three magnitudes higher than concentrations measured in the environment and thus, should not be viewed representative for oxazepam contaminated ecosystems.

This thesis dealt with the techniques that could be used for the pre-assessment of contaminated sites. The goals of the thesis were based on a simple fact that every contaminated site possesses certain potential to degrade natural resources, specifically groundwater and land resources. The thesis focused on using mathematical and statistical techniques to predict the maximum length of contaminated plumes or Lmax, which it considered as a key parameter that could be used for the site assessment. As the first thesis work, data from KORA sites were compiled and analysed. From the analyses, it was found that the Lmax for BTEX plumes are in average under 150 m long. Further, for this work, Analytical Models that can be used to estimate Lmax were reviewed and, examples comparing model and fifield Lmax were presented. The second work for the thesis focused on a development and analysis of a new 3D-analytical model for a fifinite planar and fully penetrating source. An implicit expression for predicting Lmax was obtained. The analysis of the developed model suggested that the longest Lmax will result if the source takes an approximately square shape. The last part of the thesis improved the 3D-analytical model obtained in the second work by presenting an expression for a fifinite planar source that only partially penetrates the aquifer. For this work, a very simple numerical technique was developed that not only simplififies numerical analysis of the scenarios considered in this thesis but it also bears potentials to be used for very complex subsurface reaction transport scenarios. This thesis has been successful in narrowing research-gaps on problems related to contaminated sites management. / Diese Doktorarbeit befasste sich mit Methoden, welche für eine Vorabbewertung von kontaminierten Standorten genutzt werden können. Die Ziele der Arbeit basierten auf dem einfachen Fakt, dass jeder kontaminierte Standort ein bestimmtes Potential besitzt, natürliche Ressourcen, speziell Grundwasser- und Bodenressourcen, in ihrer Qualität negativ zu beeinträchtigen. Die Arbeit war auf die Nutzung mathematischer und statistischer Techniken zur Abschätzung der maximalen Schadstofffahnenlänge, auch Lmax, fokussiert, welche als entscheidender Parameter für die Standortbewertung genutzt werden kann. Der erste Teil der Doktorarbeit beinhaltete die Zusammenstellung und Analyse von Daten einer Vielzahl von KORA-Standorten. Anhand dieser Untersuchungen konnte festgestellt werden, dass Lmax von BTEX-Fahnen im Mittel unterhalb von 150 m liegt. Des Weiteren wurden für diese Arbeit analytische Modelle, welche für die Abschätzung von Lmax genutzt werden können, kritisch bewertet und vergleichende Beispiele zwischen mit Modellierung bestimmter und im Feld ermittelter Lmax präsentiert. Der zweite Teil der Doktorarbeit zielte auf die Entwicklung und Analyse eines neuen dreidimensionalen, analytischen Models für eine finite, planare und über die komplette Mächtigkeit vorherrschende Quelle ab. Es konnte ein impliziter mathematischer Ausdruck zur Vorhersage von Lmax gewonnen werden. Die Analyse des Models wies darauf hin, dass maximale Lmax erreicht werden, wenn die Quelle eine annähernd quadratische Form aufweist. Der letzte Teil der Doktorarbeit diente der Weiterentwicklung des dreidimensionalen, analytischen Modells aus dem zweiten Teil durch die Entwicklung eines Ausdrucks für eine finite, planare Quelle, welche jedoch nur teilweise die Mächtigkeit des Grundwasserleiters kontaminiert. Für diese Arbeit wurde ein sehr einfacher numerischer Ansatz entwickelt, welcher die numerische Analyse der in dieser Arbeit berücksichtigten Szenarien nicht einfach nur erleichtert, sondern auch das Potential beinhaltet diesen auf komplexe, reaktive Transportszenarien im Untergrund anzuwenden. Abschließend kann gesagt werden, dass diese Arbeit erfolgreich zur Verringerung von Forschungslücken in der Problematik des Managements kontaminierter Standorte beigetragen hat.

Eutrophication is one of the key environmental problems of today, both in terms of complexity and magnitude. For the Baltic Sea (BS), eutrophication is an acute problem, leading to hypoxic conditions at the bottom; a situation that is sustained and amplified, when phosphorus is released from hypoxic sediments. Reducing nutrient loading is a top political priority but the present situation is believed to require active measures within the catchments and recipients to reduce both loading and adverse effects. Implementation of effective and cost-efficient abatement methods requires understanding of natural processes in watersheds, streams and recipients as well as technological expertise in order to compare the effects of measures of different kinds and locations. This thesis tries to combine process understanding of catchment transport behaviour, especially in coastal zones, and feasibility of certain technologies for reducing nutrient loading and effects of eutrophication in-situ. The over-arching theme is the fate of the individual contaminant, from injection to removal. Transport and dispersion in catchments are investigated, combining physically-based, distributed, numerical groundwater models with Lagrangian stochastic advective reactive solute (LaSAR) transport modelling. The approach is powerful in the sense that it incorporates catchment structural, geomorphological dispersion in the numerical model with hydrodynamic and sub-scale dispersion as well as uncertainty in the LaSAR framework. The study exemplifies the complex nature of transport time distributions in catchments in general and when varying source size and location, importance of dispersion parameters and retention due to molecular diffusion. It is shown that geomorphological control on dispersion is present even for relatively heterogeneous systems and that neither the mean residence time nor a statistical distribution may provide accurate representations of hydrological systems. To combat internal loading of P from sediments in-situ, large-scale aeration of deep waters, halocline ventilation, has been suggested. This study further investigates the feasibility of wave-powered devices to meet the energy demands for such an operation. It is shown that the required amount of oxygen needed to keep the sediments at oxic conditions could be provided, cheaply and efficiently, through the use of wave power. / QC 20120511

Le développement des activités humaines, notamment industrielles, depuis le 19ième siècle a engendré une contamination massive de l’atmosphère à la rivière, en passant par la biosphère et les sols. Si les contaminations ont fortement diminué depuis la fin des années 1960, elles persistent notamment en milieu urbain, où se concentrent un grand nombre d’activités humaines. Afin de pouvoir gérer au mieux la pollution, il est nécessaire de comprendre la dynamique de transfert des contaminants, ainsi que leurs sources, à l’échelle du continuum atmosphère – sol – rivière. Cette étude a donc pour objectif d’évaluer les variations temporelles et spatiales de deux types de contaminants historiques, les hydrocarbures aromatiques polycycliques (HAP) et certains éléments traces (ET), à l’échelle du bassin versant de l’Orge (950 km2), présentant une urbanisation croissante d’amont en aval. Plusieurs approches ont été utilisées pour tracer les transferts de particules en rivière (radionucléides ⁷Be, ²¹⁰Pb, ¹³⁷Cs), et déterminer les sources de Pb (isotopes du Pb), et les sources de HAP (rapports de molécules).Les résultats ont mis en évidence un impact important des zones urbaines sur la qualité de la rivière Orge en aval du bassin : contamination importante en métaux (Cu, Zn, Sb, Pb) et en HAP de la phase particulaire, et des niveaux élevés en SO42⁻, Na⁺ et Cl⁻, Cu, Zn et Pb dans la phase dissoute. Le traçage des sédiments par les radionucléides a permis d’observer un apport de particules provenant du ruissellement urbain en aval, et d’identifier les particules de route (ou Road Deposited Sediment) comme source principale. Les signatures isotopiques du Pb ainsi que les signatures en HAP permettent de confirmer que le ruissellement urbain est le principal vecteur de contamination. Les estimations des flux d’ET et HAP annuels et saisonniers entrants (retombées atmosphériques) et sortants (exportés par la rivière) ont mis en évidence une accumulation globale à l’échelle du bassin, qui comporte déjà un stock important de contaminants dans ses sols. Cette étude montre ainsi l’importance d’étudier la Zone Critique dans son ensemble afin d’évaluer la dynamique des contaminations au sein et entre ses différents compartiments, et met en évidence l’efficacité du couplage de plusieurs approches afin de comprendre le système entier. Ces résultats pourraient à terme permettre l’établissement d’un modèle de transfert de contaminations au sein d’un bassin urbain. / The development of human societies since the 19th century has led to deleterious impacts on the Critical Zone (from atmosphere to river, including biosphere and soils). Despite the decrease of pollutions since the late 1960’s, contaminations remain especially in urban environment, concentrating human activities. To better manage this pollution, it is necessary to understand the dynamics and pathways of contaminants through the atmosphere – soil – river continuum. The goal of this study in thus to evaluate the temporal and spatial variations of two contaminants (polycyclic aromatic hydrocarbons (PAH) and trace elements (TE)) in the Orge River catchment (900 km2, France) being under increasing urban pressure from up to downstream. Several fingerprinting approaches were used to trace sediment dynamics in the river (radionuclides: ⁷Be, ²¹⁰Pb, ¹³⁷Cs), to identify lead sources (lead isotopes) and PAH sources (PAH molecular ratios). The results demonstrated the strong influence of downstream urban areas on the river quality, with an increasing contamination for Cu, Zn, Sb, Pb and PAH in the particulate phase, and for SO42⁻, Na⁺ et Cl⁻, Cu, Zn and Pb in the dissolved phase. The sediment fingerprinting using radionuclides revealed a significant input of particles originating from urban areas and transferred through urban runoff, and identified road deposited sediments as the major source of contaminated particles downstream. Source tracking of Pb and PAH confirmed urban runoff as the main pathway of river contamination. In addition, annual and seasonal PAH and TE fluxes were estimated respectively for the atmospheric inputs, and riverine exports and revealed a global accumulation of contaminant over the catchment, already containing a significant stock of pollutants in its soils. Finally, this study highlights the need to integrate the Critical Zone and the potential of coupling multiples tracking approaches to properly evaluate the contaminant dynamics. These results may be used to establish a model of contaminants transfer in urban catchments.

Bioretention is increasingly being employed as a stormwater management tool in urban areas, with the intent of using infiltration to address both water quantity and quality concerns. However, bioretention soil media (BSM) has limited removal capacity for dissolved contaminants; hence, amendments may be justified to improve performance. In this study, the potential of five low-cost sorbents as BSM amendments – waste tire crumb rubber (WTCR), coconut coir fiber (CCF), blast furnace slag (BFS), biochar (BC) and iron coated biochar (FeBC) – were investigated for removing several classes of contaminants from simulated stormwater (SSW). The contaminated SSW contained a mixture of metals (Cr, Cd, Cu, Pb, Ni and Zn), nutrients (ammonium, nitrate, and phosphate) and PAHs (pyrene (PYR), phenanthrene (PHE), acenaphthylene (ACY) and naphthalene (NAP)). First, batch studies were used to investigate the sorption capacities, kinetics, and the effects of different water quality parameters on sorbents performance. Then, a long-term vegetated column study was conducted to investigate the performance of three amendments (CCF, WTCR, and BFS) under intermittent runoff condition considering different runoff intensities and antecedent dry periods (ADP). The long-term effects of amendments on plant health and infiltration rate of all media were also investigated. Finally, HYDRUS-1D and a cost model were used to investigate longevity and cost-effectiveness of all BSM. Batch test results revealed that among all sorbents, BC and FeBC were only effective for removing PAHs; CFF had high sorption capacity for both metals and PAHs; BFS was very effective for metals; and WTCR was effective for some of metals and PAHs. Metal removal by BFS occurred primarily via precipitation was due to the BFS mineral structure and high/alkaline pH. The effectiveness of CCF for removing both metals and PAHs was due to its lignocellulose structure and diverse functional groups. CCF could remove metals through several mechanisms including cation exchange, complexation, and electrostatic attraction, and remove PAHs through hydrophobic interaction. Biochar in this study had a highly aromatic structure with less O-containing functional groups, and PAHs were sorbed through hydrophobic pi-pi interactions. The selectivity orders of sorbents for the removal of different metals and PAHs were Cr~Cu~Pb > Ni > Cd > Zn and PYR > PHE > ACY > NAP. This selectivity was mainly caused by differences in properties of metal ions (e.g., ionic radius, hydrogen energy, etc.) and PAHs (e.g., hydrophobicity). Phosphate was removed by BFS due to its Al, Fe and Ca contents, but the other sorbents were ineffective for nutrient removal. Metals sorption capacity of sorbents was greater at higher pH, lower salinity and lower DOC; however, PAHs sorption capacity of sorbents was generally not sensitive to water quality parameters. Column experiments showed that almost all amended and non-amended BSM were able to remove > 99% of influent metals over the 7-month experiment period (except Zn in WTCR media). Cu and Cr effluent concentrations in all media (except BFS media) increased to ~ 10% of influent concentrations during heavy rainfall which was probably due to decomposition of Cu/Cr-organic matter complexes. All bioretention columns removed > 99% of PHE and PYR (higher molecular weight PAHs) regardless of rain intensity and ADP, while the performance of different media for removing the lower molecular weight PAHs (NAP and ACY) varied with the rain intensity, and removal decreased when larger storms were experimentally simulated. For nutrients, among all media, BFS-amended media had high phosphate removal capacity (> 90%). Nitrate removal in all columns was notably affected by changes in stormwater intensity and ADP, likely due to difference in degree of saturation and the potential that anoxic conditions were created, which are favorable for denitrification. All media were ineffective in ammonium removal, and ammonium production occurred throughout experiment which might be due to the lack of nitrifiers in the media. Hydraulic properties of all media were appropriate over the entire experiment. BFS-amended media had the greatest negative effect on plant health, while CCF-amended media was supportive for plants. The transport model results showed that the predicted metal breakthrough times (according to EPA criteria) for different media were 6 years for non-amended media, 7 years for WTCR media, 25 years for CCF media, and 70 years for BFS media. Modeling PAHs, nutrients and some metals (Cr and Cu) under intermittent flow conditions are complicated and other processes and models need to be investigated as future study. Finally, cost analysis results showed that among all bioretention media, CCF- and BFS-amended media with the lowest capital and maintenance costs were the most cost-effective BSM. This research will improve our understanding of BSM amendments that will improve water quality while simultaneously support bioretention system hydrologic function as well as estimating costs of bioretention systems for a long-term application. / Civil Engineering

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