A contaminação por metais pesados em corpos hídricos tem sido extensivamente tratada com motivo de grande preocupação sobretudo nos aspectos ambientais e efeitos para a saúde humana. Metais pesados apresentam respostas deletérias ao homem, sendo causa de intoxicações agudas e crônicas, além do desenvolvimento de doenças, para o meio ambiente a bioacumulação e os efeitos adversos as espécies podem criar o desequilíbrio ambiental de ecossistemas. As fontes de metais pesados em corpos d’águas, muita das vezes advém de esgotos domésticos e industriais, tratados ou não, de forma que os sistemas convencionais de tratamento de esgotos não são aptos a removerem os metais pesados de seus sistemas, assim sendo necessário outras tecnologias para sua remoção. São tecnologias utilizadas para a extração de metais pesados de efluentes os sistemas de adsorção, troca-iônica, filtração por membranas, extração líquido-líquido, e outros. A adsorção por carvão ativado é uma técnica eficiente de remoção de contaminantes orgânico e inorgânicos. Tendo em vista que a casca de arroz é um resíduo abundante é com amplo potencial de aplicação em diversos processos esta tem sido aplicado na produção de carvões ativados. Dessa forma, este trabalho investigou a eficiência da remoção de cobre em meio aquoso utilizando carvões ativados da casca de arroz. O processo de ativação por impregnação ácido e básica produziu carvões ativados com diferentes características químicas e respostas na extração de cobre em meio aquoso. Os ensaios para avaliação das variáveis independentes utilizaram do planejamento experimental por modelo fatorial. O carvão da casca de arroz ativado por hidróxido de potássio (CA-KOH) é um bom adsorvente de íons de cobre em solução com eficiências de remoção superiores a 96%. Enquanto a melhor condição para aplicação do carvão ativado por ácido fosfórico de casca de arroz (CA-H3PO4) ocorreu em pH de 7,3 por 65 minutos de tempo de contato com a remoção de 92,9% de cobre em solução. Foram estimados a partir do planejamento experimental os modelos de regressão para predição de extração de cobre, bem como suas superfícies de resposta. O CA-KOH apresentou alto potencial para aplicação em sistemas de tratamento de efluentes, sendo que a aplicação deste para atingir valores ótimos de extração deverá ocorrer em pH entre os intervalos inferior a 4 e superior 7 com o emprego de uma dosagem de 15-20 g de carvão/L de efluente. / The contamination by heavy metals in water bodies has been extensively treated because of great concern mainly on environmental aspects and effects on human health. Heavy metals present deleterious responses to humans, causing acute and chronic intoxications, besides the development of diseases, to the environment bioaccumulation and adverse effects species can create the environmental imbalance of ecosystems. Sources of heavy metals in bodies of water often come from domestic and industrial sewage, treated or untreated, so that conventional sewage treatment systems are not able to remove heavy metals from their systems, so it is necessary other technologies for its removal. The adsorption, ion exchange, membrane filtration, liquid-liquid extraction, and other technologies are used for the extraction of heavy metals from effluents. Activated carbon for adsorption is an efficient technique for removal of organic and inorganic contaminants. Considering that the rice husk is an abundant residue, it has a wide potential of application in several processes, this has been applied in the production of activated carbons. Thus, this work investigated the efficiency of the removal of copper in aqueous media using activated carbons of rice husk. The activation process by acid and basic impregnation produced activated carbons with different chemical characteristics and responses in copper extraction in aqueous medium. The trials for evaluation of the independent variables used experimental planning by factorial model. Potassium hydroxide-activated rice husk charcoal (CA-KOH) is a good solution of copper ions adsorbent with removal efficiencies greater than 96%. While the best condition for the application of activated carbon by phosphoric acid rice husk (CA-H3PO4) occurred in pH of 7.3 for 65 minutes of contact time with the removal of 92.9% copper solution. The regression models for copper extraction prediction, as well as their response surfaces, were estimated from the experimental design. The CA-KOH presented high potential for application in effluent treatment systems, and it is recommended to apply this in pH between the intervals below 4 and higher 7 using a dosage of 15-20 g of coal / L of effluent.

Produced water is one of the major by products of oil and gas exploitation which is produced in large amounts up to 80% of the waste stream. Oil and grease concentration in produced water is the key parameter that is used for compliance monitoring, because it is easy to measure. For Canadian offshore operations, the current standard is a 30-day volume weighted average oil-in-water concentration in discharged produced water not exceeding 30 mg/L. Treatment of produced water may therefore be required in order to meet pre-disposal regulatory limits. The measurement of oil in produced water is important for both process control and reporting to regulatory authorities. Without the specification of a method, reported concentrations of oil in produced water can mean little, as there are many techniques and methods available for making this measurement, but not all are suitable in a specific application. The first part of this study focused on selecting a suitable analytical method for oil and grease measurement in oil field produced water. Petroleum ether was found to offer a comparative dissolution of crude oil as dichloromethane and hexane; it was therefore used as the solvent of choice for the UV-Vis spectrophotometric analysis of oil and grease in synthetic produced water. Results from the UV-Vis spectrophotometric and FTIR spectrometric analytical methods were found to be comparable; it confirmed that UV-Vis spectrometry could potentially serve as an alternative method for measuring oil and grease in oil field produced water. However, while the UV-Vis method may have limitations in measuring oil and grease concentrations below 30 mg/L, the FT-IR method was found to be equally efficient at measuring both high and low oil and grease concentrations. Dissolved air flotation (DAF) was the primary treatment technology investigated in this study for removing oil and grease from synthetic produced water. By itself, DAF achieved less than 70% oil and grease (OG) removal, and was not able to achieve a clarified effluent OG concentration of 30 mg/L required for regulatory discharge limits. At an optimum condition of 20 mg/L ferric chloride (FeCl3) at pH 8 (70.6% OG removal), coagulation was found to significantly improve the performance of the DAF unit (p < 0.05). At the optimum conditions of 100 mg/L PAC dose, pH 8 and a mixing time of 10 minutes (77.5% OG removal) and 300 mg/L OC dose, pH 8 and a mixing time of 10 minutes (78.1% OG removal), adsorption was also found to significantly improve the performance of the DAF unit (p < 0.05 in both cases). Adsorption with organoclay was recommended as the best pre-treatment for optimizing the performance of DAF in removing oil and grease from offshore oil field produced water. The bench-scale experiments showed that turbidity removal results were consistent with the OG removal results. Without pre-treatment, DAF achieved significant removal of benzene from produced water due to the volatile nature of benzene. Therefore comparable levels of benzene removal was observed by the DAF, FeCl3/DAF, PAC/DAF and OC/DAF treatment schemes; 79.3 %, 86.6 %, 86.5 %, 83.5% respectively. Finally, as benzene is known to be carcinogenic to humans, this study recommends the incorporation auxiliary equipment in its design, for the treatment of the off-gas (VOCs, particularly BTEX) released during the removal of dissolved oil from the oil field produced water.

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Le biogaz doit être purifié pour devenir un combustible renouvelable. De nombreux traitements actuels ne sont pas satisfaisants car, pour des raisons de coûts les procédés de séparation privilégiés aboutissent souvent au rejet direct ou indirect du sulfure d'hydrogène (H2S) à l’atmosphère, c’est le cas de la séparation à l’eau sous pression. Les objectifs de la thèse portent d’abord sur l’étude et la modélisation des méthodes connues de séparation de l'hydrogène sulfuré du méthane. Les concentrations typiques varient de 200 à 5000 ppm, et la séparation devra réduire la teneur résiduelle en H2S à moins de 1 ppm. Parallèlement seront étudiées les méthodes de traitement de H2S. Une fois la (ou les) méthode(s) de séparation sélectionnée(s), des essais de validation seront effectués sur un système traitant de l’ordre de 85 Nm3/h de méthane où seront injectées des quantités de H2S variant entre 1 et 100 ppm.Cette thèse requiert des modélisations réalistes sous Aspen Plus® ou sous un code équivalent pour établir a priori des efficacités de séparation selon différentes conditions opératoires et en prenant en compte le paramètre température. L’énergie dépensée pour la séparation effective sera un des critères fort de la comparaison, de même que l’économie de matière.Une approche système est indispensable pour étudier la rétroaction de la méthode de valorisation du H2S sur la ou les méthodes séparatives. A priori c’est aussi l’outil Aspen Plus® ou équivalent qui permettra cette approche système.L’étude du procédé sera menée selon la double approche modélisation et expérimentation, pour l’étude expérimentale des méthodes séparatives, l’échelle du banc sera semi-industrielle et le banc permettra d’étudier les méthodes de séparation jusqu’à -90°C. / Biogas must be purified for becoming a renewable fuel. At now, the most part of the purification techniques are not satisfactory because they imply hydrogen sulfides (H2S) rejection to the atmosphere. One example of these methods is the treatment with high pressure water. The first objective of the thesis is modeling the conventional methods for separating H2S from methane. Typical concentrations of H2S in methane vary from 200 to 5000 pm. Separation methods must decrease the concentration of H2S in methane to less than 1 ppm. At the same time, methods for H2S treatment will be studied.Once the most appropriated separation methods will be selected, some test will be carried out on a pilot plant capable of treating 85 Nm3/h of methane, where quantities of H2S ranging from 1 and 100 ppm will be injected. These tests will allow validating the modeling of the separation process. On the basis of the obtained results, a specific test bench will be conceived and constructed for validating the selected process.The thesis work requires simulating the separation process using the software Aspen Plus® or an equivalent one. The effectiveness of different operative conditions will be tested, varying also the parameter temperature. The energy necessary for the separation will be one of the most important criteria for the comparison, as well as the mass consumption of the different fluids involved in the process.A system approach is fundamental for evaluating the backward effect of the H2S valorization method on the separation techniques. The process simulator (Aspen Plus® or equivalent) will allow the system approach.The study will involve modeling and experimental parts. The experimental part will be carried out taking advantage of a semi-industrial size test bench, allowing studying the separation methods down to -90°C.