581 resultados para REMEDIATION


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Relatório de estágio apresentado à Escola Superior de Educação de Santarém do Instituto Politécnico de Santarém para obtenção do grau de Mestre em ensino do 1.º e do 2.º ciclo do ensino básico

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For fifty years (1949–99) the now-abandoned Giant Mine in Yellowknife emitted arsenic air and water pollution into the surrounding environment. Arsenic pollution from Giant Mine had particularly acute health impacts on the nearby Yellowknives Dene First Nation (YKDFN), who were reliant on local lakes, rivers, and streams for their drinking water, in addition to frequent use of local berries, garden produce, and medicine plants. Currently, the Canadian government is undertaking a remediation project at Giant Mine to clean up contaminated soils and tailings on the surface and contain 237,000 tonnes of arsenic dust that are stored underground at the Giant Mine. Using documentary sources and statements of Yellowknives Dene members before various public hearings on the arsenic issue, this paper examines the history of arsenic pollution at Giant Mine as a form of “slow violence,” a concept that reconfigures the arsenic issue not simply as a technical problem, but as a historical agent of colonial dispossession that alienated an Indigenous group from their traditional territory. The long-term storage of arsenic at the former mine site means the effects of this slow violence are not merely historical, but extend to the potentially far distant future.

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Trinitrotoluene in the purification step (TNT) produced in industries, are carried out two washes at the end of the process. The first wash is done with vaporized water, which originates from the first effluent called yellow water, then the second washing with the use of sodium sulfite is performed (Na2SO3), generating a second effluent red water. This study aimed to study the individual effects, as well as the association of heterogeneous photocatalysis using TiO2 and biological treatment in air lift reactor using activated sludge (bacterial biomass) for the remediation of wastewater contaminated with nitroaromatic compounds in order to reduce toxicity and adjust the legal parameters according to regulatory agencies for disposal in waterways. The photocatalytic treatment was conducted by factorial design obtaining the best reaction conditions (pH 6.5 and concentration of TiO2 0.1 gL-1), with best results obtained at 360 minutes of reaction, reducing the absorbance 97.00%, 94.20% of the chemical oxygen demand (COD), 67.70% of total phenols, as well as a total reduction of observed peaks and assigned to nitroaromatic compounds by high-performance liquid chromatography. In the biological treatment, there was a 53.40% reduction in absorbance at 275 nm 10.00% 36.00% COD and total phenols in a short time (3 days), while for extended periods (48 days) there was an antagonistic influence on the results so that was the elevation of these parameters (COD and total phenols) instead of reducing. Chromatographic analysis confirmed the effectiveness of the biological degradation by reducing the peaks corresponding to compounds DNT and TNT. The Association of photocatalytic and biological treatments decreased results in the order of 91.10% absorbance, 70.26% of total phenols and 88.87% of COD. While the combination of biological and photocatalytic treatments generated relatively lower efficiencies, with 77.30% of absorbance reduction, 62.10% reduction of total phenols and a decrease of 87.00% of COD. In general, when comparing the chemical and biological processes in isolation, the photocatalytic treatment showed the best results. However, comparing the results of isolation and established associations, the association biological x photocatalysis showed more promising results in the treatment of red water effluent.

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Marine Recirculating Aquaculture Systems (RAS) produce great volume of wastewater, which may be reutilized/recirculated or reutilized after undergoing different treatment/remediation methods, or partly discharged into neighbour water-bodies (DWW). Phosphates, in particular, are usually accumulated at high concentrations in DWW, both because its monitoring is not compulsory for fish production since it is not a limiting parameter, and also because there is no specific treatment so far developed to remove them, especially in what concerns saltwater effluents. As such, this work addresses two main scientific questions. One of them regards the understanding of the actual (bio)remediation methods applied to effluents produced in marine RAS, by identifying their advantages, drawbacks and gaps concerning their exploitation in saltwater effluents. The second one is the development of a new, innovative and efficient method for the treatment of saltwater effluents that potentially fulfil the gaps identified in the conventional treatments. Thereby, the aims of this thesis are: (i) to revise the conventional treatments targeting major contaminants in marine RAS effluents, with a particular focus on the bioremediation approaches already conducted for phosphates; (ii) to characterize and evaluate the potential of oyster-shell waste collected in Ria de Aveiro as a bioremediation agent of phosphates spiked into artificial saltwater, over different influencing factors (e.g., oyster-shell pre-treatment through calcination, particle size, adsorbent concentration). Despite the use of oyster-shells for phosphorous (P) removal has already been applied in freshwater, its biosorptive potential for P in saltwater was never evaluated, as far as I am aware. The results herein generated showed that NOS is mainly composed by carbonates, which are almost completely converted into lime (CaO) after calcination (COS). Such pre-treatment allowed obtaining a more reactive material for P removal, since higher removal percentages and adsorption capacity was observed for COS. Smaller particle size fractions for both NOS and COS samples also increased P removal. Kinetic models showed that NOS adsorption followed, simultaneously, Elovich and Intraparticle Difusion kinetic models, suggesting that P removal is both a diffusional and chemically rate-controlled process. The percentage of P removal by COS was not controlled by Intraparticle Diffusion and the Elovich model was the kinetic model that best fitted phosphate removal. This work demonstrated that waste oyster-shells, either NOS or COS, could be used as an effective biosorbent for P removal from seawater. Thereby, this biomaterial can sustain a cost-effective and eco-friendly bioremediation strategy with potential application in marine RAS.

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This design thesis is an inquiry of the highly industrialized urban landscape of the Lake Calumet Complex on the South Side of the City of Chicago. It examines geologic and anthropogenic strata within this region as waste used for staging various social, industrial, and ecological systems. Today, these social, industrial, and ecological systems are not responsive to each other and certainly do not possess resilient attributes that would allow them to interact within the landscape in perpetuity. The resulting design strategy seeks to re-think the treatment of waste in the landscape into a new framework for future park design. This park will serve as grounds to interweave these complex systems in order to rehabilitate ecosystem functions and improve water quality. Additionally the park hybridizes many social and ecological functions to improve community recreational opportunities and gain public acceptance and appeal.

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The textile industry generates a large volume of high organic effluent loading whoseintense color arises from residual dyes. Due to the environmental implications caused by this category of contaminant there is a permanent search for methods to remove these compounds from industrial waste waters. The adsorption alternative is one of the most efficient ways for such a purpose of sequestering/remediation and the use of inexpensive materials such as agricultural residues (e.g., sugarcane bagasse) and cotton dust waste (CDW) from weaving in their natural or chemically modified forms. The inclusion of quaternary amino groups (DEAE+) and methylcarboxylic (CM-) in the CDW cellulosic structure generates an ion exchange capacity in these formerly inert matrix and, consequently, consolidates its ability for electrovalent adsorption of residual textile dyes. The obtained ionic matrices were evaluated for pHpcz, the retention efficiency for various textile dyes in different experimental conditions, such as initial concentration , temperature, contact time in order to determine the kinetic and thermodynamic parameters of adsorption in batch, turning comprehensive how does occur the process, then understood from the respective isotherms. It was observed a change in the pHpcz for CM--CDW (6.07) and DEAE+-CDW (9.66) as compared to the native CDW (6.46), confirming changes in the total surface charge. The ionized matrices were effective for removing all evaluated pure or residual textile dyes under various tested experimental conditions. The kinetics of the adsorption process data had best fitted to the model a pseudosecond order and an intraparticle diffusion model suggested that the process takes place in more than one step. The time required for the system to reach equilibrium varied according to the initial concentration of dye, being faster in diluted solutions. The isotherm model of Langmuir was the best fit to the experimental data. The maximum adsorption capacity varied differently for each tested dye and it is closely related to the interaction adsorbent/adsorbate and dye chemical structure. Few dyes obtained a linear variation of the balance ka constant due to the inversion of temperature and might have influence form their thermodynamic behavior. Dyes that could be evaluated such as BR 18: 1 and AzL, showed features of an endothermic adsorption process (ΔH° positive) and the dye VmL presented exothermic process characteristics (ΔH° negative). ΔG° values suggested that adsorption occurred spontaneously, except for the BY 28 dye, and the values of ΔH° indicated that adsorption occurred by a chemisorption process. The reduction of 31 to 51% in the biodegradability of the matrix after the dye adsorption means that they must go through a cleaning process before being discarded or recycled, and the regeneration test indicates that matrices can be reused up to five times without loss of performance. The DEAE+-CDW matrix was efficient for the removal of color from a real textile effluent reaching an UV-Visible spectral area decrease of 93% when applied in a proportion of 15 g ion exchanger matrix L-1 of colored wastewater, even in the case of the parallel presence of 50 g L-1 of mordant salts in the waste water. The wide range of colored matter removal by the synthesized matrices varied from 40.27 to 98.65 mg g-1 of ionized matrix, obviously depending in each particular chemical structure of the dye upon adsorption.

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L’objectif principal de cette thèse était de créer, d’implanter et d’évaluer l’efficacité d’un programme de remédiation cognitive, intervenant de façon comparable sur les aspects fluide (Gf) et cristallisé (Gc) de l’intelligence, au sein d’une population d’intérêt clinique, les adolescents présentant un fonctionnement intellectuel limite (FIL). Compte tenu de la forte prévalence de ce trouble, le programme de remédiation GAME (Gains et Apprentissages Multiples pour Enfant) s’est développé autour de jeux disponibles dans le commerce afin de faciliter l’accès et l’implantation de ce programme dans divers milieux. Le premier article de cette thèse, réalisé sous forme de revue systématique de la littérature, avait pour objectif de faire le point sur les études publiées utilisant le jeu comme outil de remédiation cognitive dans la population pédiatrique. L’efficacité, ainsi que la qualité du paradigme utilisé ont été évaluées, et des recommandations sur les aspects méthodologiques à respecter lors de ce type d’étude ont été proposées. Cet article a permis une meilleure compréhension des écueils à éviter et des points forts méthodologiques à intégrer lors de la création du programme de remédiation GAME. Certaines mises en garde méthodologiques relevées dans cet article ont permis d’améliorer la qualité du programme de remédiation cognitive développé dans ce projet de thèse. Compte tenu du peu d’études présentes dans la littérature scientifique concernant la population présentant un FIL (70

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The potential of swamp arum ( Lasimorpha senegalensis ) seeds as a low-cost adsorbent for the removal of Hg (II) ions from aqueous solution was investigated in this study. The influence of initial metal concentration on the percent adsorption of Hg (II) ions onto powdered swamp arum seeds was studied in a batch system and the filtrate was analyzed using Atomic Absorption Spectrometry (AAS). The percent adsorbed for 10, 20, 40, 60 and 80 mg/L of the aqueous solution were 97.7, 98.9, 99.3, 99.7, and 96.5% respectively. Three isotherms; Langmuir, Freundlich, and BET were used to model the equilibrium sorption of Hg (II) ions onto powdered swamp arum seeds, with a correlation coefficient of 0.998, 0.784 and0.842 respectively. The Langmuir model fitted the equilibrium data best, with a correlation coefficient of 0.998 and a maximum adsorption capacity qm, of 5.917 mg/g. Thus, indicating monolayer coverage on the adsorbent. The results showed that swamp arum seed have the potential to be applied as alternative lowcost biosorbent in the remediation of heavy metal contamination in waste water.

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People and cities alike derive their life from water. Water is consequently influenced by the actions of people and cities. This crucial relationship deserves to be commemorated, and also analyzed as further human development, sea level rise, and ecological remediation efforts influence its form. This thesis seeks to remember the past condition, recognize the current, and positively influence the future of this relationship in Baltimore’s Inner Harbor through a waterfront park and harbor history museum. How can a building and a site work together to improve the health of local hydrology while still effectively serving its human community? This thesis weaves these opportunities together to create a responsible redesign of Rash Field and Federal Hill on the south side of the Inner Harbor in Baltimore.

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This chapter explores the relationship between environmental conflicts and technical progress, trying to understand, in the case of large mines of the Iberian Pyrite Belt, in Alentejo, how emerging environmental problems conditioned the performance or led to the search for alternative technical solutions, taking as chronological limit for this observation the beginning of World War II. In the absence of the archives of the companies, the research was based on existing administrative documents in the state archives (mining engineers reports, the licensing of mining activities), on reports and documents published in specialized mining press, in particular, the Bulletin of the Ministry of Public Works, Trade and Industry, the Journal of Public Works, Trade and Industry (both in Portuguese), and finally in the local press. Despite that limitation, the information available shows that in global competition markets, the success of the British enterprise in Santo Domingo had the active search for new technical solutions for the creation and adaptation of existing knowledge to local problems in order to maximize the mineral resources available. The early development of the hydrometallurgical processes for the treatment of poor ores, named ‘natural cementation’, can be explained as the way these companies tried to solve problems of competitiveness, boosting economies of scale. Thus, they transferred the environmental costs previously limited to agriculture to more fragile social groups, the poor fishermen of Guadiana River and of Vila Real de Santo António. Therefore, the hydrometallurgy of pyrites was developed locally, pioneered in Santo Domingo that allowed the survival and expansion of the British company from the late 1870s, that is, at a time when most small mines shut since they were not able to compete globally. Through different consented and regulated processes (judicial), through conflict or parliamentary mediation, the State imposed exceptionally additional costs to companies, either for compensation, the imposing the application of remediation measures to reduce the environmental damage in some cases, thus contributing to derail some projects. These cases suggest that the interaction between local conflicts, corporate behavior and technological progress proves to be complex. This article aims to contribute to the debate on economic and social history between the environment and technological progress, arguing that the fixed costs and economic imponderable social risks were factors that encouraged the companies to search for new solutions and to introduce innovations since that would allow the expansion of their activity. In this process the companies sometimes faced environmental dilemmas and unforeseen costs with consequences on the economy of firms. The nature of the knowledge needed to address the environmental problems they created, however, is of a very different nature from that knowledge needed to face the environmental burdens that were inherent to the development of its activity.

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Despite the recent synthesis and identification of a diverse set of new nanophotocatalysts that has exploded recently, titanium dioxide (TiO2) remains among the most promising photocatalysts because it is inexpensive, non-corrosive, environmentally friendly, and stable under a wide range of conditions. TiO2 has shown excellent promise for solar cell applications and for remediation of chemical pollutants and toxins. Over the past few decades, there has been a tremendous development of nanophotocatalysts for a variety of industrial applications (i.e. for water purification and reuse, disinfection of water matrices, air purification, deodorization, sterilization of soils). This paper details traditional and new industrial routes for the preparation of nanophotocatalysts and the characterization techniques used to understand the physical chemical properties of them, like surface area, ζ potential, crystal size, and phase crystallographic, morphology, and optical transparency. Finally we present some applications of the industrial nanophotocatalysts.

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The gas migration during the cementing of wells is one of the main problems of oil wells engineering. Its occurrence can cause severe problems since shortly to loss of control of the well after cementation. Recently, 20/04/2010 In an accident of major proportions in the Gulf of Mexico, among other factors, faulty cementing operation provided the gas migration, causing the accident, in which 11 people died and 17 were injured occurred. Besides the serious consequences that can be caused by gas migration, remediation of the problem, which is made by injecting cement in damaged areas, usually involves additional costs and is not always effective. Therefore, preventing gas migration to be preferred. Some methods are used to prevent the migration of the pressurized gas as the annular space, application of pressure pulses, reducing the height of the cement column compressible cement pastes of low permeability, pastes and to control free filtered water, and binders of thixotropic cement expandable and flexible. Thus, the cement pastes used to prevent gas migration must meet the maximum these methods. Thus, this study aimed to formulate a cement paste to prevent gas migration, using the expanded vermiculite, and evaluate the behavior of the folder trials necessary for use in oil wells. Free water content, rheological properties, compressive strength, loss of liquid phase sedimentation of solids, specific weight, thickening time and gas migration: The following tests were performed. The results show that meets the specifications paste formulated for use in oil wells and the use of expanded vermiculite contribute to the absorption of free water, thixotropy and low density. The absorption of free water is proven to result in zero percentage test free water content, thixotropy is observed with the high value of the initial gel strength (Gi) in testing rheological properties and low density is proven in test weight specific

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The remediation of paracetamol (PA), an emerging contaminant frequently found in wastewater treatment plants, has been studied in the low concentration range (0.3–10 mg L−1) using as adsorbent a biomass-derived activated carbon. PA uptake of up to 100 mg g−1 over the activated carbon has been obtained, with the adsorption isotherms being fairly explained by the Langmuir model. The application of Reichemberg and the Vermeulen equations to the batch kinetics experiments allowed estimating homogeneous and heterogeneous diffusion coefficients, reflecting the dependence of diffusion with the surface coverage of PA. A series of rapid small-scale column tests were carried out to determine the breakthrough curves under different operational conditions (temperature, PA concentration, flow rate, bed length). The suitability of the proposed adsorbent for the remediation of PA in fixed-bed adsorption was proven by the high PA adsorption capacity along with the fast adsorption and the reduced height of the mass transfer zone of the columns. We have demonstrated that, thanks to the use of the heterogeneous diffusion coefficient, the proposed mathematical approach for the numerical solution to the mass balance of the column provides a reliable description of the breakthrough profiles and the design parameters, being much more accurate than models based in the classical linear driving force.

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The produced water is a byproduct formed due to production of petroleum and carries with it a high amount of contaminants such as oil particles in suspension, organic compounds and metals. Thus, these latter pollutants are very difficult to treat because of its high solubility in water. The objective of this work is to use and evaluate a microemulsioned system to remove metals ( K , Mg , Ba , Ca , Cr , Mn , Li , Fe ) of synthetic produced water. For the extraction of metals, it was used a pseudoternary diagram containing the following phases: synthetic produced water as the aqueous phase (AP), hexane as organic phase (OP), and a cosurfactant/surfactant ratio equal to four (C/S = 4) as the third phase, where the OCS (saponified coconut oil) was used as surfactant and n-butanol as cosurfactant. The synthetic produced water was prepared in a bench scale and the region of interest in the diagram for the removal of metals was determined by experimental design called. Ten points located in the phase Winsor II were selected in an area with a large amount of water and small amounts of reagents. The samples were analyzed in atomic absorption spectrometer, and the results were evaluated through a statistical assesment, allowing the efficiency analysis of the effects and their interactions. The results showed percentages of extraction above 90% for the metals manganese, iron, chromium, calcium, barium and magnesium, and around 45% for metals lithium and potassium. The optimal point for the simultaneous removal of metals was calculated using statistical artifact multiple response function (MR). This calculation showed that the point of greatest extraction of metals occurs was the J point, with the composition [72% AP, 9% OP, 19% C/S], obtaining a global extraction percentage about 80%. Considering the aspects analyzed, the microemulsioned system has shown itself to be an effective alternative in the extraction of metals on synthetic produced water remediation