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A avaliação do risco a contaminação e a escolha de técnicas de remediação de poluentes em aquíferos fraturados depende da quantificação dos fenômenos envolvidos no transporte de solutos. A geometria da fratura, usualmente caracterizada pela abertura, é o principal parâmetro que indiretamente controla o transporte nos aquíferos fraturados. A simplificação mais comum desse problema é assumir que as fraturas são um par de placas planas e paralelas, isto é, com uma abertura constante. No entanto, por causa do limitado número de trabalhos experimentais, não está esclarecida a adequabilidade do uso de uma abertura constante para simular o transporte conservativo em fraturas do Aquífero Serra Geral (ASG), Brasil. O objetivo deste trabalho é avaliar a influência da abertura de uma fratura natural do Aquífero Serra Geral sob o transporte conservativo de solutos. Uma amostra natural de basalto fraturado foi usada em um experimento hidráulico e de transporte de um traçador conservativo (escala de laboratório). O campo de abertura foi medido usando a técnica avançada, de alta resolução e tridimensional, chamada microtomografia computadorizada de raios-X. A concentração de traçador medida foi utilizada para validar uma solução analítica unidimensional da Equação de Advecção-dispersão (ADE). O desemprenho do ajuste da ADE às curvas de passagem experimentais foi avaliado para quatro diferentes tipos de aberturas constantes. Os resultados mostraram que o escoamento de água e o transporte de contaminantes pode ocorrer através de fraturas micrométricas, ocasionando, eventualmente, a contaminação do ASG. A abertura de balanço de massa é a única que pode ser chamada propriamente de \"abertura equivalente\". O uso de aberturas constantes na ADE não permitiu representar completamente o formato das curvas de passagem porque o campo de velocidade não é uniforme e intrinsicamente bidimensional. Portanto, na simulação do transporte deve-se incorporar a heterogeneidade da abertura da fratura. / The contamination risk assessment and the choice of suitable cleanup techniques for pollutants in fractured rock depends on the quantification of the transport phenomena. Fracture geometry often described by the apertures is the major parameter that controls indirectly solute transport in fractured rock. The simplest approach is describing fractures as a pair of smooth parallel plates with constant aperture. However, there is a lack of information about the suitability for using a constant aperture for the conservative solute transport prediction in a single fracture of Serra Geral Aquifer (SGA), Brazil. The aim of this work is to evaluate the effect of aperture variability in a natural single rough-walled fracture of Serra Geral Aquifer on conservative solute transport. A natural core of fractured basalt was used for a hydraulic and tracer tests (laboratory scale). The aperture field was measured using the advanced, high-resolution and tridimensional technique X-ray computed tomography. The measured tracer concentration was validated by means of an analytical solution of the Advection-dispersion Equation (ADE). The ADE fit performance was measured against experimental breakthrough curves for four distinct kind of constant apertures. It was found that water flow and solute transport can take place through micrometric fractures, eventually leading the SGA contamination. Results show that the mass balance aperture is the only appropriate \"equivalent aperture\" for describing solute transport in a single rough-walled fracture. The results showed that ADE is not appropriate for modeling the complete behavior of experimental breakthrough curves because of the dimensional non-uniform velocity field. Therefore, the aperture heterogeneity must be considered in solute transport simulation.

A avaliação do risco a contaminação e a escolha de técnicas de remediação de poluentes em aquíferos fraturados depende da quantificação dos fenômenos envolvidos no transporte de solutos. A geometria da fratura, usualmente caracterizada pela abertura, é o principal parâmetro que indiretamente controla o transporte nos aquíferos fraturados. A simplificação mais comum desse problema é assumir que as fraturas são um par de placas planas e paralelas, isto é, com uma abertura constante. No entanto, por causa do limitado número de trabalhos experimentais, não está esclarecida a adequabilidade do uso de uma abertura constante para simular o transporte conservativo em fraturas do Aquífero Serra Geral (ASG), Brasil. O objetivo deste trabalho é avaliar a influência da abertura de uma fratura natural do Aquífero Serra Geral sob o transporte conservativo de solutos. Uma amostra natural de basalto fraturado foi usada em um experimento hidráulico e de transporte de um traçador conservativo (escala de laboratório). O campo de abertura foi medido usando a técnica avançada, de alta resolução e tridimensional, chamada microtomografia computadorizada de raios-X. A concentração de traçador medida foi utilizada para validar uma solução analítica unidimensional da Equação de Advecção-dispersão (ADE). O desemprenho do ajuste da ADE às curvas de passagem experimentais foi avaliado para quatro diferentes tipos de aberturas constantes. Os resultados mostraram que o escoamento de água e o transporte de contaminantes pode ocorrer através de fraturas micrométricas, ocasionando, eventualmente, a contaminação do ASG. A abertura de balanço de massa é a única que pode ser chamada propriamente de \"abertura equivalente\". O uso de aberturas constantes na ADE não permitiu representar completamente o formato das curvas de passagem porque o campo de velocidade não é uniforme e intrinsicamente bidimensional. Portanto, na simulação do transporte deve-se incorporar a heterogeneidade da abertura da fratura. / The contamination risk assessment and the choice of suitable cleanup techniques for pollutants in fractured rock depends on the quantification of the transport phenomena. Fracture geometry often described by the apertures is the major parameter that controls indirectly solute transport in fractured rock. The simplest approach is describing fractures as a pair of smooth parallel plates with constant aperture. However, there is a lack of information about the suitability for using a constant aperture for the conservative solute transport prediction in a single fracture of Serra Geral Aquifer (SGA), Brazil. The aim of this work is to evaluate the effect of aperture variability in a natural single rough-walled fracture of Serra Geral Aquifer on conservative solute transport. A natural core of fractured basalt was used for a hydraulic and tracer tests (laboratory scale). The aperture field was measured using the advanced, high-resolution and tridimensional technique X-ray computed tomography. The measured tracer concentration was validated by means of an analytical solution of the Advection-dispersion Equation (ADE). The ADE fit performance was measured against experimental breakthrough curves for four distinct kind of constant apertures. It was found that water flow and solute transport can take place through micrometric fractures, eventually leading the SGA contamination. Results show that the mass balance aperture is the only appropriate \"equivalent aperture\" for describing solute transport in a single rough-walled fracture. The results showed that ADE is not appropriate for modeling the complete behavior of experimental breakthrough curves because of the dimensional non-uniform velocity field. Therefore, the aperture heterogeneity must be considered in solute transport simulation.

Na região de Ribeirão Preto está localizado um dos pólos produtores de cana-de-açúcar uma das principais culturas da economia brasileira, com vasta área cultivada e uso intensivo de herbicidas, dos quais é preciso destacar o diuron e a hexazinona, pois ambos possuem elevado potencial de contaminação em águas superficiais e subterrâneas. Diversas tecnologias podem ser utilizadas para remover da água esses microcontaminantes, pelo fato de, neste caso, não ser eficiente a técnica de tratamento em ciclo completo (ou convencional). Neste trabalho de pesquisa foram investigadas as combinações de preoxidação com cloro e dióxido de cloro, de adsorção em carvão ativado pulverizado e granular, associadas ao tratamento em ciclo completo. A água de estudo foi preparada em laboratório, com características similares às do rio Pardo – futuro manancial para abastecimento da cidade de Ribeirão Preto, e fortificada com diuron e hexazinona. Ensaios de bancada feitos em jarteste e filtros de laboratório permitiram concluir que a adsorção em carvão ativado (pulverizado e granular) foi eficiente na remoção dos herbicidas. Foi construída e operada uma instalação piloto com colunas de adsorção, em carvão ativado granular, cujos resultados obtidos mostraram que a difusividade intrapartícula predominante entre o carvão e os herbicidas diuron e hexazinona pode ser considerada constante, em relação ao tamanho do grão de carvão ativado. Os resultados também possibilitaram a validação do método de ensaios rápidos em coluna de carvão ativado em escala reduzida, com vista à predição do tempo de ruptura de um filtro de carvão ativado granular em escala real. Para as condições ensaiadas, a adsorção em carvão ativado granular mostrou ser 12% mais eficiente que em carvão ativado pulverizado, cujas taxas de utilização foram de 10,7 e 12,0 miligrama de carvão por litro de água tratada, respectivamente. Foram dimensionados os sistemas para utilizar carvão ativado pulverizado e granular em uma ETA de 1 m3/s e contabilizados os custos de implantação e de operação. Embora os custos de implantação do sistema de carvão ativado granular tenham resultado da ordem de 3 vezes os do pulverizado, os custos totais em valor presente seriam igualados em 5 anos, podem ser até 23% menores em 20 anos – o que mostra a viabilidade técnico-financeira desta alternativa no tratamento de águas contaminadas com herbicidas. / Sugarcane is one of the major crops of the Brazilian economy and the city of Ribeirao Preto is in one of the largest sugarcane producing regions, with a vast sugarcane plantation area and intensive use of herbicides, especially diuron and hexazinone, which have high potential to contaminate surface waters and groundwater. Several different technologies can be used to remove these micro-contaminants from water since, in this case, conventional treatment is not an efficient technique. In the present study, the combinations of pre-oxidation with chlorine and chlorine dioxide and adsorption in powdered and granular activated carbon associated with the conventional treatment were investigated. The water sample investigated in this study was prepared in a laboratory with similar characteristics to that of the Pardo river - future source of water supply for the city of Ribeirao Preto - and supplemented with diuron and hexazinone. Bench-scale experiments performed using Jartest equipment and laboratory filters showed that the adsorption in activated carbon (powdered and granular) was effective in removing the herbicides. A pilot granular activated carbon column was built and operated, and the results showed that the prevailing intraparticle diffusivity between the carbon and the herbicides diuron and hexazinone can be considered constant, do not change with particle size. The results obtained also enabled the validation of the rapid small-scale column test (RSSCT) method to predict the full scale breakthrough time of a granular activated carbon filter. Under the conditions evaluated, the adsorption in granular activated carbon proved to be 12% more efficient than that in powdered activated carbon, whose carbon usage rates were 10.7 and 12.0 milligrams per liter of treated water, respectively. The systems were designed to use powdered and granular activated carbon in a 1 m3/s conventional water treatment plant, and the implementation and operation costs were calculated. Although the capital costs of the granular activated carbon system were about 3 times higher than those of the powdered activated carbon, these costs would be the same in 5 years and could even be 22% lower in 20 years, which shows the technical-financial feasibility of this alternative to the treatment of water contaminated with herbicides.

Na região de Ribeirão Preto está localizado um dos pólos produtores de cana-de-açúcar uma das principais culturas da economia brasileira, com vasta área cultivada e uso intensivo de herbicidas, dos quais é preciso destacar o diuron e a hexazinona, pois ambos possuem elevado potencial de contaminação em águas superficiais e subterrâneas. Diversas tecnologias podem ser utilizadas para remover da água esses microcontaminantes, pelo fato de, neste caso, não ser eficiente a técnica de tratamento em ciclo completo (ou convencional). Neste trabalho de pesquisa foram investigadas as combinações de preoxidação com cloro e dióxido de cloro, de adsorção em carvão ativado pulverizado e granular, associadas ao tratamento em ciclo completo. A água de estudo foi preparada em laboratório, com características similares às do rio Pardo – futuro manancial para abastecimento da cidade de Ribeirão Preto, e fortificada com diuron e hexazinona. Ensaios de bancada feitos em jarteste e filtros de laboratório permitiram concluir que a adsorção em carvão ativado (pulverizado e granular) foi eficiente na remoção dos herbicidas. Foi construída e operada uma instalação piloto com colunas de adsorção, em carvão ativado granular, cujos resultados obtidos mostraram que a difusividade intrapartícula predominante entre o carvão e os herbicidas diuron e hexazinona pode ser considerada constante, em relação ao tamanho do grão de carvão ativado. Os resultados também possibilitaram a validação do método de ensaios rápidos em coluna de carvão ativado em escala reduzida, com vista à predição do tempo de ruptura de um filtro de carvão ativado granular em escala real. Para as condições ensaiadas, a adsorção em carvão ativado granular mostrou ser 12% mais eficiente que em carvão ativado pulverizado, cujas taxas de utilização foram de 10,7 e 12,0 miligrama de carvão por litro de água tratada, respectivamente. Foram dimensionados os sistemas para utilizar carvão ativado pulverizado e granular em uma ETA de 1 m3/s e contabilizados os custos de implantação e de operação. Embora os custos de implantação do sistema de carvão ativado granular tenham resultado da ordem de 3 vezes os do pulverizado, os custos totais em valor presente seriam igualados em 5 anos, podem ser até 23% menores em 20 anos – o que mostra a viabilidade técnico-financeira desta alternativa no tratamento de águas contaminadas com herbicidas. / Sugarcane is one of the major crops of the Brazilian economy and the city of Ribeirao Preto is in one of the largest sugarcane producing regions, with a vast sugarcane plantation area and intensive use of herbicides, especially diuron and hexazinone, which have high potential to contaminate surface waters and groundwater. Several different technologies can be used to remove these micro-contaminants from water since, in this case, conventional treatment is not an efficient technique. In the present study, the combinations of pre-oxidation with chlorine and chlorine dioxide and adsorption in powdered and granular activated carbon associated with the conventional treatment were investigated. The water sample investigated in this study was prepared in a laboratory with similar characteristics to that of the Pardo river - future source of water supply for the city of Ribeirao Preto - and supplemented with diuron and hexazinone. Bench-scale experiments performed using Jartest equipment and laboratory filters showed that the adsorption in activated carbon (powdered and granular) was effective in removing the herbicides. A pilot granular activated carbon column was built and operated, and the results showed that the prevailing intraparticle diffusivity between the carbon and the herbicides diuron and hexazinone can be considered constant, do not change with particle size. The results obtained also enabled the validation of the rapid small-scale column test (RSSCT) method to predict the full scale breakthrough time of a granular activated carbon filter. Under the conditions evaluated, the adsorption in granular activated carbon proved to be 12% more efficient than that in powdered activated carbon, whose carbon usage rates were 10.7 and 12.0 milligrams per liter of treated water, respectively. The systems were designed to use powdered and granular activated carbon in a 1 m3/s conventional water treatment plant, and the implementation and operation costs were calculated. Although the capital costs of the granular activated carbon system were about 3 times higher than those of the powdered activated carbon, these costs would be the same in 5 years and could even be 22% lower in 20 years, which shows the technical-financial feasibility of this alternative to the treatment of water contaminated with herbicides.

Wastewater treatment plants (WWTPs) play a vital role in protecting the environment from much of the waste produced by humans. This includes not only human waste, but everything that makes its way into a sewerage system including greywater, stormwater, and potentially hazardous chemicals from, inter alia, chemical spills. The effects of a chemical spill if it enters a WWTP can be disastrous, resulting in the ineffective treatment of incoming water for prolonged periods of time (Söhr, 2014). This can lead to one of the dilemmas of urban wastewater systems, notably, whether it is more damaging to allow a chemical spill to bypass a WWTP, or to attempt to treat all or some of the spill and risk damaging the microbes working in the biological treatment processes (Schütze, 2002). In order to better inform policy makers and process engineers at WWTPs of which measures to take in the event of a spill, solute transport characteristics of a specific sewerage network must be defined.  A series of tracer tests were performed along The Käppala Association’s northern sewerage network to determine these solute transport characteristics, notably the dispersion coefficient which strongly affects the level of dilution that occurs between the injection point and the inlet. A simple solute transport model, carried out in Excel, was created using the Advection-Dispersion Equation (ADE) and the Manning-Strickler equation to relate flow measurements to flow velocity. Results from the experiments show that a dispersion coefficient of 1.55m2/s appears to be applicable throughout the whole of the tunnel network. A depth dependent Manning-Strickler coefficient seems to describe the flow-velocity relationship, however, this method has not been validated. The ADE begins to lose accuracy in describing solute transport as the distance from the inlet and the number of pumping stations the plume goes through increases. / Avloppsreningsverk spelar en viktig roll för att skydda miljön från mycket av det avfall som produceras av människor. Detta inkluderar inte bara mänskligt avfall utan allt som tar sig in i ett avloppssystem, till exempel gråvatten, dagvatten och potentiellt farliga kemikalier från bland annat industriutsläpp. Effekterna av ett kemiskt utsläpp kan vara katastrofala om det kommer in i ett avloppsreningsverk, vilket resulterar i ineffektiv behandling av inkommande vatten under längre perioder (Söhr, 2014). Detta är ett dilemma i urbana avloppssystem – ska man låta ett kemiskt utsläpp ledas förbi ett avloppsreningsverk, eller försöka behandla hela eller en del av utsläppet och riskera att skada mikroberna i den biologiska reningsprocessen (Schütze, 2002). För att beslutsfattare och processingenjörer vid avloppsreningsverk ska kunna fatta rätt beslut om vilka åtgärder som ska vidtas vid utsläpp måste egenskaperna för det specifika avloppsnätet definieras.  Syftet med detta projekt är att uppskatta transportparametrar och karakterisera utspädning i nätverket genom att utföra en serie spårningsförsök i Käppalaverkets upptagningsområde. För att nå syftet fanns det flera mål som genomförts: Genomföra en litteraturstudie  Skapa en förutsägbar modell i Excel baserad på flödesdata längs Käppalaförbundets tunnelsystem Genomföra en serie spårningsförsök vid flera punkter längs tunnelsystemet  Strukturerad datalagring av resultaten så att data är lätt att hitta för framtida projekt  Metoderna kan delas i två: modellering och försök. För att skapa en modell och simulera transport av ett ämne i nätet får man definiera relevanta ekvationer. För den hydrauliska delen av modellen användes Manning-Strickler-ekvationen. Resultaten från detta användes sedan i den förenklade formen av advektion-spridningsekvationen (ADE). Tunnelsystemet uppdelades i flera sektioner med samma egenskaper såsom form och geometri, och en anpassad form av ADE användes emellan sektionerna. För att nå framgång i försöken krävdes att rätt spårämne valdes. Uranin användes i försöken på grund av sina ogiftiga och stabila egenskaper och den låga detektionsgränsen. Injiceringspunkterna låg gradvis längre bort från inloppet; Försök 1 var 9km från verket till nästan 46km vid Arlanda flygplats för Försök 3.  Resultaten från simuleringarna användes för att planera injiceringstid, start- och stopptid för provtagningen och provtagningsfrekvens. Resultatet från första försöket användes för att kalibrera modellen inför de andra försöken. Resultaten från alla försök visade att en dispersionskoefficient på 1.55m2/s, som är ett mått på utspädning i nätet, verkar tillämpligt till hela tunnelsystemet. Koefficienten kan dock vara högre i de kommunala näten. En djupberoende metod för att härleda Mannings tal formulerades, men det kräver ytterligare validering.  Från alla tre försöken kan vi härleda ett förhållande mellan avstånd från inlopp och toppkoncentration samt avstånd från inlopp och varaktigheten av genombrottskurvan. Toppkoncentration visar ett linjärt eller kanske logaritmiskt förhållande med distans, och varaktigheten av genombrottskurvan visar ett starkt linjärt förhållande. Kunskaper om detta är viktigt när man vill genomföra en riskbedömning av ett kemiskt utsläpp i upptagningsområdet eftersom det ger en insikt om hur det kan påverka den biologiska reningen i ett avloppsreningsverk.  Sammanfattningsvis fungerar den enkla formen av ADE bra, men viss avvikelse ses i experiment 3. Detta beror kanske på möjliga övergående lagringsprocesser vid pumpstationerna längs tunnelsystemet. En enda dispersionskoefficient, som är ett mått på utspädning, är tillämplig i hela huvudtunnelsystemet, men spridningen i kommunala nätverk är sannolikt högre. Ytterligare arbete behövs inom dessa kommunala nätverk för att kvantifiera deras effekter.  På grundval av resultaten från detta projekt rekommenderas ytterligare forskningsundersökningar om vad som händer med föroreningar i avloppsreningsverket. Eftersom slammet vid Käppalaverket används för biogasproduktion och är Revaq-certifierat för användning på jordbruksmark är föroreningsnivån i slammet mycket viktigt både ur produktivitets- och hälso- och säkerhetsperspektiv.

A intensificação da degradação ambiental impulsionada pelas atividades antrópicas tem comprometido a qualidade da água. A presença de metais potencialmente tóxicos no ambiente provoca diversos impactos na fauna e flora, como, por exemplo, o processo de magnificação trófica. Assim, é fundamental que estudos de adsorção desses contaminantes sejam realizados, a fim de buscar novos métodos que permitam a remoção dos mesmos no meio aquático. O metal crômio está nos efluentes de diversos processos industriais, como curtumes, refino de petróleo, galvanoplastia, soldagem e cromagem. Esse metal na forma hexavalente possuí efeito tóxico a biota e riscos à saúde humana, indicando a necessidade da realização de estudos para sua remoção de efluentes industriais e corpos d\'água. O biopolímero quitosana tem sido reportado em diversos estudos como bioadsorvente de alto potencial de retenção de metais, por conta da presença de amino-grupos em sua estrutura. Além disso, a quitosana possui propriedades singulares e é obtida da quitina, um dos biopolímeros mais abundantes na natureza. Com a finalidade de avaliar a capacidade de adsorção de Cr (VI) pelo biopolímero quitosana em forma de pérolas (P-QTS), realizou-se ensaios de adsorção em processo contínuo com diferentes concentrações do metal cromo em coluna de leito fixo, preenchida pelo material adsorvente (P-QTS). Além disso, realizou-se testes de toxicidade com os organismos Daphnia magna, Allonais inaequalis e Chironomus xanthus no afluente e efluente da coluna de adsorção, buscando avaliar a toxicidade dessas amostras para os organismos e a consequente eficácia do tratamento da solução de dicromato de potássio na coluna de leito fixo com as P-QTS. As curvas de ruptura indicaram que para as maiores concentrações de K2Cr2O7 houve intensificação da saturação da CALF (coluna de adsorção de leito fixo), e, consequentemente, a zona de transferência de massa (ZTM) se deslocou no sentido descendente do leito fixo da coluna de adsorção. A razão C/Co (concentração efluente/concentração afluente) aumentou de maneira significativa no decorrer do ensaio para as maiores concentrações afluentes (25 e 28,5 mg L-1) de K2Cr2O7 alcançando valores de até 0,4, e, isso demonstra a saturação de parte das P-QTS na coluna de leito fixo. De maneira geral, a remoção de Cr VI foi alta (superior a 50% e atingindo a máxima de 98%) para os tempos estudados na presente pesquisa, sendo maior nos menores tempos (60 e 120 min) do ensaio, estado em que os sítios ativos para adsorção das P-QTS provavelmente estavam livres. Da extração do cromo das P-QTS obteve-se valor máximo de 8,18 mg g-1 e mínimo de 0,42 mg g-1 de massa adsorvida por massa de adsorvente, o que indica variação de acordo com a concentração da solução de K2Cr2O7 afluente a CALF, ou seja, para as maiores concentrações, maior a quantidade adsorvida de Cr VI por massa de adsorvente (P-QTS). Alguns pesquisadores obtiveram relação de 2,6 mg de crômio (III) /g de quitosana indicando que as P-QTS na coluna de leito fixo possuem boa capacidade de adsorção. Os testes de toxicidade mostraram diferentes sensibilidades dos organismos-teste às soluções de dicromato de potássio, sendo na ordem decrescente: Chironomus xanthus < Allonais inaequalis < Daphnia magna. A coluna de adsorção de leito fixo diminuiu, de modo geral, a mortalidade dos organismos-teste comparando o afluente e efluente, principalmente das amostras efluentes de menor tempo (60 e 120 min) de ensaio de adsorção. A média de comprimento das larvas de C. xanthus reduziu (10,07 mm > 8,34 mm > 4,59 mm), de modo geral, a medida que o tempo de ensaio (60, 120 e 180 min) aumentou, indicando aumento da concentração de Cr VI nos efluentes. / The intensification of environmental degradation driven by anthropic activities has led to a decrease in water quality. The presence of potentially toxic metals in the environment causes several impacts on fauna and flora, such as the trophic magnification process. Thus, it is fundamental that adsorption studies of these contaminants are carried out in order to search for new methods that allow their removal in the aquatic environment. Chromium metal is in the effluents of various industrial processes, such as tanning, petroleum refining, electroplating, welding and chrome plating. The chromium in the hexavalent form has a toxic effect on biota and risks to human health, indicating the need to carry out studies to your removal of industrial effluents and water bodies. The biopolymer chitosan has been reported in several studies as bioadsorbent with high potential for metal retention, due to the presence of amino groups in its structure. In addition, chitosan has unique properties and is obtained from chitin, one of the most abundant biopolymers in nature. In order to evaluate the Cr (VI) adsorption capacity of the chitosan biopolymer in the form of beads (P-QTS), adsorption tests were carried out in continuous process with different concentrations of the chromium metal in a fixed bed column, filled by adsorbent material (P-QTS). Besides that, toxicity tests were carried out with the organisms Daphnia magna, Allonais inaequalis and Chironomus xanthus on the affluent and effluent of the adsorption column, seeking to evaluate the toxicity of these samples to the organisms and the consequent effectiveness of the treatment of potassium dichromate solution in the fixed bed column with the P-QTS. The breakthrough curves indicated that for the higher concentrations of K2Cr2O7 there was an increase in the saturation of the CALF (fixed bed adsorption column), and consequently the mass transfer zone (ZTM) moved downwards from the fixed bed of the column of adsorption. The C/Co (affluent concentration/effluent concentration) ratio increased significantly during the test for the highest affluent concentrations, reaching values of up to 0.4 for the affluent concentrations of 25 and 28.5 mg L-1 of K2Cr2O7, and this demonstrates the saturation of part of the P-QTS in the fixed bed column. The removal of Cr VI was high (higher than 50% and reaching a maximum of 98%) for the times studied in the present study, but it was higher in the lower times (60 and 120 min) of the test, in which the active sites for adsorption of P-QTS probably were free. From the extraction of chromium from P-QTS, a maximum value of 8.18 mg g-1 and a minimum of 0.42 mg g-1 was obtained, which indicates variation according to the concentration of the K2Cr2O7 solution affluent to CALF, i.e the adsorbed amount of Cr VI per adsorbent mass (P-QTS) is higher at higher concentrations. Some authors have obtained a ratio of 2.6 mg of chromium (III) / g of chitosan indicating that the P-QTS in the fixed bed column have good adsorption capacity. The toxicity tests showed different sensitivities of the test organisms to the solutions of potassium dichromate, being in descending order: Chironomus xanthus < Allonais inaequalis < Daphnia magna. The fixed-bed adsorption column decreased the mortality of the test organisms by comparing the affluent and the effluent, mainly from the effluent samples with the shortest adsorption test time (60 and 120 min). The mean length of the C. xanthus larvae decreased (10.07 mm> 8.34 mm> 4.59 mm), generally as the test time (60, 120 and 180 min) increased, indicating rise in Cr VI concentration in the effluents.

A intensificação da degradação ambiental impulsionada pelas atividades antrópicas tem comprometido a qualidade da água. A presença de metais potencialmente tóxicos no ambiente provoca diversos impactos na fauna e flora, como, por exemplo, o processo de magnificação trófica. Assim, é fundamental que estudos de adsorção desses contaminantes sejam realizados, a fim de buscar novos métodos que permitam a remoção dos mesmos no meio aquático. O metal crômio está nos efluentes de diversos processos industriais, como curtumes, refino de petróleo, galvanoplastia, soldagem e cromagem. Esse metal na forma hexavalente possuí efeito tóxico a biota e riscos à saúde humana, indicando a necessidade da realização de estudos para sua remoção de efluentes industriais e corpos d\'água. O biopolímero quitosana tem sido reportado em diversos estudos como bioadsorvente de alto potencial de retenção de metais, por conta da presença de amino-grupos em sua estrutura. Além disso, a quitosana possui propriedades singulares e é obtida da quitina, um dos biopolímeros mais abundantes na natureza. Com a finalidade de avaliar a capacidade de adsorção de Cr (VI) pelo biopolímero quitosana em forma de pérolas (P-QTS), realizou-se ensaios de adsorção em processo contínuo com diferentes concentrações do metal cromo em coluna de leito fixo, preenchida pelo material adsorvente (P-QTS). Além disso, realizou-se testes de toxicidade com os organismos Daphnia magna, Allonais inaequalis e Chironomus xanthus no afluente e efluente da coluna de adsorção, buscando avaliar a toxicidade dessas amostras para os organismos e a consequente eficácia do tratamento da solução de dicromato de potássio na coluna de leito fixo com as P-QTS. As curvas de ruptura indicaram que para as maiores concentrações de K2Cr2O7 houve intensificação da saturação da CALF (coluna de adsorção de leito fixo), e, consequentemente, a zona de transferência de massa (ZTM) se deslocou no sentido descendente do leito fixo da coluna de adsorção. A razão C/Co (concentração efluente/concentração afluente) aumentou de maneira significativa no decorrer do ensaio para as maiores concentrações afluentes (25 e 28,5 mg L-1) de K2Cr2O7 alcançando valores de até 0,4, e, isso demonstra a saturação de parte das P-QTS na coluna de leito fixo. De maneira geral, a remoção de Cr VI foi alta (superior a 50% e atingindo a máxima de 98%) para os tempos estudados na presente pesquisa, sendo maior nos menores tempos (60 e 120 min) do ensaio, estado em que os sítios ativos para adsorção das P-QTS provavelmente estavam livres. Da extração do cromo das P-QTS obteve-se valor máximo de 8,18 mg g-1 e mínimo de 0,42 mg g-1 de massa adsorvida por massa de adsorvente, o que indica variação de acordo com a concentração da solução de K2Cr2O7 afluente a CALF, ou seja, para as maiores concentrações, maior a quantidade adsorvida de Cr VI por massa de adsorvente (P-QTS). Alguns pesquisadores obtiveram relação de 2,6 mg de crômio (III) /g de quitosana indicando que as P-QTS na coluna de leito fixo possuem boa capacidade de adsorção. Os testes de toxicidade mostraram diferentes sensibilidades dos organismos-teste às soluções de dicromato de potássio, sendo na ordem decrescente: Chironomus xanthus < Allonais inaequalis < Daphnia magna. A coluna de adsorção de leito fixo diminuiu, de modo geral, a mortalidade dos organismos-teste comparando o afluente e efluente, principalmente das amostras efluentes de menor tempo (60 e 120 min) de ensaio de adsorção. A média de comprimento das larvas de C. xanthus reduziu (10,07 mm > 8,34 mm > 4,59 mm), de modo geral, a medida que o tempo de ensaio (60, 120 e 180 min) aumentou, indicando aumento da concentração de Cr VI nos efluentes. / The intensification of environmental degradation driven by anthropic activities has led to a decrease in water quality. The presence of potentially toxic metals in the environment causes several impacts on fauna and flora, such as the trophic magnification process. Thus, it is fundamental that adsorption studies of these contaminants are carried out in order to search for new methods that allow their removal in the aquatic environment. Chromium metal is in the effluents of various industrial processes, such as tanning, petroleum refining, electroplating, welding and chrome plating. The chromium in the hexavalent form has a toxic effect on biota and risks to human health, indicating the need to carry out studies to your removal of industrial effluents and water bodies. The biopolymer chitosan has been reported in several studies as bioadsorbent with high potential for metal retention, due to the presence of amino groups in its structure. In addition, chitosan has unique properties and is obtained from chitin, one of the most abundant biopolymers in nature. In order to evaluate the Cr (VI) adsorption capacity of the chitosan biopolymer in the form of beads (P-QTS), adsorption tests were carried out in continuous process with different concentrations of the chromium metal in a fixed bed column, filled by adsorbent material (P-QTS). Besides that, toxicity tests were carried out with the organisms Daphnia magna, Allonais inaequalis and Chironomus xanthus on the affluent and effluent of the adsorption column, seeking to evaluate the toxicity of these samples to the organisms and the consequent effectiveness of the treatment of potassium dichromate solution in the fixed bed column with the P-QTS. The breakthrough curves indicated that for the higher concentrations of K2Cr2O7 there was an increase in the saturation of the CALF (fixed bed adsorption column), and consequently the mass transfer zone (ZTM) moved downwards from the fixed bed of the column of adsorption. The C/Co (affluent concentration/effluent concentration) ratio increased significantly during the test for the highest affluent concentrations, reaching values of up to 0.4 for the affluent concentrations of 25 and 28.5 mg L-1 of K2Cr2O7, and this demonstrates the saturation of part of the P-QTS in the fixed bed column. The removal of Cr VI was high (higher than 50% and reaching a maximum of 98%) for the times studied in the present study, but it was higher in the lower times (60 and 120 min) of the test, in which the active sites for adsorption of P-QTS probably were free. From the extraction of chromium from P-QTS, a maximum value of 8.18 mg g-1 and a minimum of 0.42 mg g-1 was obtained, which indicates variation according to the concentration of the K2Cr2O7 solution affluent to CALF, i.e the adsorbed amount of Cr VI per adsorbent mass (P-QTS) is higher at higher concentrations. Some authors have obtained a ratio of 2.6 mg of chromium (III) / g of chitosan indicating that the P-QTS in the fixed bed column have good adsorption capacity. The toxicity tests showed different sensitivities of the test organisms to the solutions of potassium dichromate, being in descending order: Chironomus xanthus < Allonais inaequalis < Daphnia magna. The fixed-bed adsorption column decreased the mortality of the test organisms by comparing the affluent and the effluent, mainly from the effluent samples with the shortest adsorption test time (60 and 120 min). The mean length of the C. xanthus larvae decreased (10.07 mm> 8.34 mm> 4.59 mm), generally as the test time (60, 120 and 180 min) increased, indicating rise in Cr VI concentration in the effluents.

L’objectif de ce travail est d’étudier les phénomènes de transport des solutés hors équilibre physique dans la ZNS des Calcaires de Beauce. Cette étude a été réalisée en deux parties, une partie laboratoire qui a consisté en la réalisation d’expériences d’élution sur colonnes non perturbées en régime permanent pour trois intensités de précipitation (4, 8, 16 mm/h) et en régime transitoire avec ou sans drainage, en condition non saturées. Les colonnes ont été prélevées dans deux faciès de la ZNS des Calcaires de Beauce : un faciès homogène et un faciès hétérogène. La seconde partie de cette étude a été réalisé in situ, avec des expériences de traçage au bromure (Br-) et de Bleu Brillant (BB) réalisées sur une fosse du site du Lycée de Saussaye (Chartres). Les expériences en régime permanent ont montré que les deux faciès n’avaient pas le même comportement face au transport de soluté. Les courbes de percée pour le faciès homogène s’expliquent par un modèle de transport de type convectif dispersif classique (CDE), alors les CP pour le faciès hétérogène s’expliquent par un modèle de transport de type eau mobile – eau immobile (MIM). Les expériences en régime transitoire ont montré que la concentration augmentait pendant le drainage des colonnes. Ce phénomène peut s’expliquer par une distribution de la concentration en fonction de la taille des pores. L’analyse des colonnes au microtomographe a montré que la présence d’une matrice limoneuse dans le calcaire favorisait le transport. Les expériences de traçage au Br- et BB sur le terrain ont montré que les faciès de calcaire sont très variables à l’échelle de quelques mètres. Les points d’échantillonnage les plus bas restituent en premier le traceur (Br-). Ce transport préférentiel s’explique par l’agencement des faciès, qui a un impact important sur la forme du panache observé de BB. Des digitations apparaissent lorsqu’un contraste de perméabilité et l’agencement des faciès engendrent des écoulements localisés rapides. Les phénomènes hors équilibre existent dans la ZNS du calcaire de Beauce et ont pour origine différents facteurs : la variation des conditions à la limite supérieur, l’état hydrique, l’hétérogénéité du milieu, tel qu’observé à l’échelle de la colonne, et le contraste de perméabilité et la présence de structures lithologique qui engendrent du transport préférentiel à l’échelle du terrain. / The purpose of this work is to study solute transport processes under physical non-equilibrium in the unsaturated zone of the Beauce limestone. This study has been divided into two parts, a laboratory part which consisted in conducting elution experiments with a steady state flow with three rainfall (4,8,16 mm/h) and under transient flow with or without drainage, in unsaturated structured columns. The columns have been sampled into two facies of the unsaturated zone of the Beauce limestone: a homogenous facies and a heterogenous facies. The second part of this study has been realized in situ, with tracing experiments realized on a pit dug at the site of the Lycée de Saussaye (Chartres). The experiments in a steady state regime showed that the two facies do not have the same behaviour regarding solute transports. The breakthrough curve (BTC) for the homogeneous facies is explained with a classical convection dispersion solute transport model. The BTC for the heterogenous facies could be explained only with the mobile-immobile water model. The experiments under transient flow showed a rise of concentration during drainage. This phenomenon could be explained by a heterogeneous distribution of concentration as a function of pore size. The tracing experiments with bromide (Br -) and Brillant Blue (BB) show that the limestone facies are very variable at the field scale. The lowest sampling points returned first the Br - tracer. This preferential transport could be explained by the facies layout which has an important impact on the shape of the observed distribution of BB. Digitations appear when permeability contrast and facies layout produce localised fast flows. Non-equilibrium phenomena exist in the unsaturated zone of the Beauce limestone and have different factors as origins: condition at the upper boundary limit, moisture condition, heterogeneity of the medium, as observed on columns, and contrast of permeability and lithological structures as observed at the field scale.

The elimination of natural organic matter (NOM) is an important aim of water treatment in demineralisation plants of power stations. NOM is regarded as corrosion risk factor in the steam water cycle because of its potential to decompose into low-molecular-weight (LMW) acids and carbon dioxide. Further, the removal of NOM is also one of the main objectives in the drinking water production, since it can cause i) colour, taste and odour problems, ii) formation of carcinogen halogenated disinfection by-products (DBPs) after disinfection with chlorine and iii) bacterial growth in the water distribution system. In earlier studies, it was found that anion exchange is a successful method to remove NOM fractions. However, NOM fractions with low charge density (LMW neutrals and hydrophobic organic carbon (HOC)) and/or large molecular size (biopolymers and particulate organic carbon (POC)) could not be removed in some cases in satisfying quantities. The aim of the present work was to investigate the uptake performance of different anion exchange resins (AERs) in regard to problematic NOM fractions. The AERs differ especially in their functional groups (tertiary versus quaternary amines) and matrix material (polystyrene versus polyacrylic resins). The use of different AERs provides an option to identify possible interactions between adsorbate (NOM fractions) and adsorber (AERs) as well as the mechanism which determine the removal efficiency. The NOM fraction adsorption onto AERs was studied in equilibrium and fixed-bed experiments with three types of starch with different molecular size distributions (model substances for biopolymer fraction) as well as 2-naphthol (model substance for the LMW neutral fraction) at acidic pH (relevant for water in demineralisation plants of power stations) and neutral pH (covering most raw waters). Furthermore, the NOM fraction uptake from “real” acidic and neutral water samples, obtained from a demineralisation plant of a power station, was estimated for different AERs. Results were discussed in terms of size-exclusion, anion exchange and hydrophilic/hydrophobic repulsion. In case that size-exclusion influences the NOM uptake onto AERs, it was found that the smaller the size of the NOM molecules and the higher the water content of the AERs, the more effective the uptake is. Thus, for the removal of biopolymers and POC, polyacrylic resins with high water content could be a good choice. Contrary, polystyrene AERs are the most effective resins in the removal of NOM fractions, if no size-exclusion occurs. They seem to be able to uptake more hydrophilic NOM fractions by polar/ionic interactions between acids/acidic components and tertiary/quaternary amines as well as to remove more hydrophobic NOM fractions by π-π stacking and/or hydrophobic interactions on the polystyrene matrix. Further, it was found that the higher the total volume (anion exchange) capacity of an AER, the higher its NOM removal by polar/ionic interactions can be. At acidic pH, weak/medium base AERs have higher total volume (anion exchange) capacities than strong base AERs, whereas, at neutral pH, strong base AERs have the highest ones. In view of these results, the application of polyacrylic AERs with high water content can be recommended to remove NOM components with large molecular size in demineralisation and drinking water plants. If there is a higher amount of smaller NOM fractions, especially LMW neutrals, than polystyrene weak/medium base AERs should be favoured in demineralisation plants and polystyrene strong base AERs in drinking water treatment plants. From the engineering point of view, breakthrough curve (BTC) prediction models are important for the design of fixed-bed filter. Therefore, two different BTC model approaches were tested in the present study to describe the single-solute adsorption onto AERs: i) the homogenous surface diffusion model (HSDM) with linear driving force (LDF) approach for surface diffusion, known from activated carbon adsorption, and ii) the Glueckauf/Helfferich formulae as an extension of the height equivalent to a theoretical plate (HETP) model, initially used to describe ion exchange processes. It was found that the Glueckauf/Helfferich approach is not only a suitable tool for the fast calculation of BTCs for ionic components, but it can also successfully be applied, after considering the Freundlich model for the mass balance, for the rapid prediction of BTCs for single-solute organic molecules. For competitive BTC predictions, the ideal adsorbed solution theory (IAST) within the LDF model was applied. All calculated BTCs fit the experimental data in a good manner. Thus, the investigated BTC models can be applied for estimating the breakthrough bed volumes of different AERs to avoid leakage of NOM in the drinking or demineralised water caused by overloading. / Die Entfernung von natürlichen organischen Substanzen (NOM) ist ein wichtiges Ziel für die Herstellung von Reinstwasser im Kraftwerksbetrieb, da diese sich im Wasser/Dampf-Kreislauf zu niedermolekularen Säuren und Kohlenstoffdioxid zersetzen können und so ein potentielles Korrosionsrisiko darstellen. Außerdem ist die Elimination von natürlichen organischen Substanzen einer der Schwerpunkte in der Trinkwasseraufbereitung, da NOM im Trinkwasser folgende Konsequenzen verursachen können i) Farb-, Geschmacks- und Geruchsprobleme, ii) Bildung von kanzerogen halogenierten Desinfektionsnebenprodukten nach der Desinfektion mit Chlor und iii) Bakterienwachstum im Wasserverteilungssystem. In früheren Untersuchungen wurde festgestellt, dass Anionenaustauscherharze (AERs) die NOM-Fraktionen in der Regel erfolgreich aufnehmen können. Nur NOM-Fraktionen mit geringer Ladungsdichte (niedermolekulare Neutralstoffe und hydrophober organischer Kohlenstoff) und/oder großer Molekülgröße (Biopolymere und partikulärer organischer Kohlenstoff) können unter bestimmten Bedingungen nicht in zufriedenstellender Menge entfernt werden. Ziel dieser Arbeit war es, das Aufnahmeverhalten unterschiedlicher AERs hinsichtlich problematischer NOM-Fraktionen zu untersuchen. Die AERs unterscheiden sich vor allem in ihren funktionellen Gruppen (tertiäre versus quaternäre Amine) und ihrer Matrix (Polystyren- versus Polyacryl-Harze). Die Verwendung unterschiedlicher AERs erlaubt es, mögliche Wechselwirkungen zwischen Adsorbat (NOM-Fraktionen) und Adsorber (AERs) und die Mechanismen, die die NOM-Aufnahme entscheidend bestimmen, zu identifizieren. Die Entfernung von NOM-Fraktionen durch AERs wurde in Gleichgewichts- und Festbett-versuchen mittels dreier Stärketypen mit unterschiedlicher Molekülgrößenverteilung (Modellsubstanzen für die Biopolymere) und 2-Naphthol (Modellsubstanz für die Neutralstoffe) unter sauren pH-Bedingungen (relevant für die Herstellung von Reinstwasser im Kraftwerksbetrieb) und neutralen pH-Bedingungen (bedeutsam für die meisten Rohwässer) untersucht. Außerdem sollte das Adsorptionsverhalten von AERs bezüglich verschiedener NOM-Fraktionen unter Einsatz von „real“ neutralen und sauren Wasserproben aus einer Wasseraufbereitungsanlage eines Kraftwerksbetriebes eingeschätzt werden. In dieser Arbeit konnte gezeigt werden, dass falls Größenausschluss die NOM-Aufnahme von AERs beeinflusst, dann ist die Adsorption der NOM-Fraktionen umso größer, je kleiner die NOM-Moleküle sind und je höher der Wassergehalt der AERs ist. Daher kann für die Entfernung von größeren Biopolymeren, der Einsatz von AERs mit Polyacryl-Matrix und hohem Wassergehalt die beste Option sein. AERs mit Polystyren-Matrix besitzen die höchste Aufnahmekapazität für NOM-Fraktionen, falls kein Größenausschluss auftritt. Es scheint für sie möglich zu sein, sowohl hydrophile NOM-Fraktionen durch polare/ionische Wechselwirkungen zwischen NOM Säuren/sauren Komponenten und tertiären/quaternären Aminen aufzunehmen als auch hydrophobe NOM-Fraktionen durch π-π Anziehungen und/oder hydrophobe Interaktionen an die Polystyren-Matrix zu binden. Weiterhin konnte gezeigt werden, dass je höher die Gesamtvolumenkapazität eines AERs, desto größer ist die NOM-Entfernung auf Grund von polaren/ionischen Wechselwirkungen. Es gilt, dass schwach/mittel basische AERs im Vergleich zu stark basischen AERs höhere Gesamtvolumenkapazitäten unter sauren pH-Bedingungen besitzen und stark basische AERs die höchsten Gesamtvolumenkapazitäten unter neutralen pH-Bedingungen aufweisen. Auf Grund dieser Ergebnisse ist es möglich, die Verwendung von AERs mit Polyacryl-Matrix und hohem Wassergehalt für die Entfernung von NOM-Fraktionen mit großer Molekülgröße in Reinst- und Trinkwasseraufbereitungsanlagen zu empfehlen. Falls es einen höheren Anteil von kleineren NOM-Fraktionen, im Besonderen Neutralstoffen, gibt, sollte die Verwendung von schwach/mittel basischen AERs in Vollentsalzungsanlagen von Kraft-werksbetrieben und stark basischen AERs in Trinkwasseraufbereitungsanlagen bevorzugt werden. Vor allem im Hinblick auf technische Anwendungen ist es wichtig, Durchbruchskurven (BTC) vorausberechnen zu können. In der vorliegenden Arbeit wurden zwei Modellansätze für die Berechnung von BTCs für die Einkomponentenadsorption getestet: i) das homogene Oberflächendiffusionsmodell mit linearer Triebkraft (LDF), bekannt aus Untersuchungen zur Aufnahme von NOM an Aktivkohle, und ii) die Glueckauf/Helfferich-Formeln, primär verwendet für die Beschreibung von Ionenaustauschprozessen. Es konnte gezeigt werden, dass das Glueckauf/Helfferich-Verfahren nicht nur ein geeignetes Instrument für die schnelle Berechnung von BTCs für ionische Komponenten ist, sondern dass dieses, nach Berücksichtigung des Freundlich-Ansatzes in der Massenbilanz, auch erfolgreich angewendet werden kann, um BTCs für Einkomponentenadsorption von Organika zu berechnen. Für die Vorausberechnung von BTCs für Mehrkomponentensysteme wurde die Theorie der idealen adsorbierten Lösung im LDF-Modell genutzt. Die berechneten BTCs stimmen in guter Qualität mit den experimentell ermittelten BTCs überein. Die Ergebnisse verdeutlichen, dass die untersuchten BTC-Modelle eingesetzt werden können, um Durchbruchspunkte für die jeweiligen AERs zu bestimmen und damit die Gefahr des Schlupfes von NOM ins Trink- bzw. Reinstwasser zu minimieren.