Liquid waste discharged from industrial outfalls is categorized into two major classes based on their density. One type is the effluent that has a higher density than that of the ambient water body. In this case, the discharged effluent has a tendency to sink as a negatively buoyant jet. The second type is the effluent that has a lower density than that of the ambient water body and is hence defined as a (positively) buoyant jet that causes the effluent to rise. Negatively/Positively buoyant jets are found in various civil and environmental engineering projects: discharges of desalination plants, discharges of cooling water from nuclear power plants turbines, mixing chambers, etc. This thesis investigated the mixing and dispersion characteristics of such jets numerically. In this thesis, mixing behavior of these jets is studied using a finite volume model (OpenFOAM). Various turbulence models have been applied in the numerical model to assess the accuracy of turbulence models in predicting the effluent discharges in submerged outfalls. Four Linear Eddy Viscosity Models (LEVMs) are used in the positively buoyant wall jet model for discharging of heated waste including: standard k-ε, RNG k-ε, realizable k-ε and SST k-ω turbulence models. It was found that RNG k-ε, and realizable k-ε turbulence models performed better among the four models chosen. Then, in the next step, numerical simulations of 30˚ and 45˚ inclined dense turbulent jets in stationary ambient water have been conducted. These two angles are examined in this study due to lower terminal rise height for 30˚ and 45˚, which is very important for discharges of effluent in shallow waters compared to higher angles. Five Reynolds-Averaged Navier-Stokes (RANS) turbulence models are applied to evaluate the accuracy of CFD predictions. These models include two LEVMs: RNG k-ε, and realizable k-ε; one Nonlinear Eddy Viscosity Model (NLEVM): Nonlinear k-ε; and two Reynolds Stress Models (RSMs): LRR and Launder-Gibson. It has been observed that the LRR turbulence model as well as the realizable k-ε model predict the flow more accurately among the various turbulence models studied herein.

CO2 sequestration is one of the proposed methods for reducing anthropogenic CO2 emissions to the atmosphere and therefore mitigating global climate change. Few studies on storing CO2 in an aquifer have been conducted on a regional scale. This study offers a conceptual approach to increasing the storage efficiency of CO2 injection in saline formations and investigates what an actual CO2 storage project might entail using field data for the Woodbine aquifer in East Texas. The study considers three aquifer management strategies for injecting CO2 emissions from nearby coal-fired power plants into the Woodbine aquifer. The aquifer management strategies studied are bulk CO2 injection, and two CO2-brine displacement strategies. A conceptual model performed with homogeneous and average reservoir properties reveals that bulk injection of CO2 pressurizes the aquifer, has a storage efficiency of 0.46% and can only last for 20 years without risk of fracturing the CO2 injection wells. The CO2-brine displacement strategy can continue injecting CO2 for as many as 240 years until CO2 begins to break through in the production wells. This offers 12 times greater CO2 storage efficiency than the bulk injection strategy. A full field simulation with a geological model based on existing aquifer data validates the storage capacity claims made by the conceptual model. A key feature in the geological model is the Mexia-Talco fault system that serves as a likely boundary between the saline aquifer region suitable for CO2 storage and an updip fresh water region. Simulation results show that CO2 does not leak into the fresh water region of the iv aquifer after 1000 years of monitoring if the faults have zero transmissibility, but a negligible volume of brine eventually gets through the mostly sealing fault system as pressure across the faults slowly equilibrates during the monitoring period. However, for fault transmissibilities of 0.1 and 1, both brine and CO2 leak into the fresh water aquifer in increasing amounts for both bulk injection and CO2-brine displacement strategies. In addition, brine production wells draw some fresh water into the saline aquifer if the Mexia-Talco fault system is not sealing. A CO2 storage project in the Woodbine aquifer would impact as many as 15 counties with high-pressure CO2 pipelines stretching as long as 875 km from the CO2 source to the injection site. The required percentage of power plant energy capacity was 7.43% for bulk injection, 7.9% for the external brine disposal case, and 10.2% for the internal saturated brine injection case. The estimated total cost was $0.00132–$0.00146/kWh for the bulk injection, $0.00191–$0.00211/kWh for the external brine disposal case, and $0.0019–$0.00209/kWh for the internal saturated brine injection case.

Σκοπός της παρούσας διπλωματικής εργασίας είναι η περιγραφή και η οικονομική αξιολόγηση μιας μονάδας αφαλάτωσης θαλασσινού νερού μικρής δυναμικότητας η οποία θα είναι ενεργειακά αυτόνομη καθώς και η πειραματική μελέτη της μεθόδου της ηλιακής απόσταξης. Η μονάδα αφαλάτωσης που περιγράφουμε είναι μια μονάδα αντίστροφης όσμωσης και η περιγραφή της έγινε με τη χρήση ενός λογισμικού σχεδιασμού και προσομοίωσης μεμβρανών. Σκοπός μας είναι να εξετάσουμε τις ενεργειακές απαιτήσεις αυτής της μονάδας συναρτήσει παραμέτρων όπως η ποιότητα του νερού τροφοδοσίας, το είδος και ο αριθμός των μεμβρανών καθώς και η παραγωγικότητα της. Η ενεργειακή αυτονομία της μονάδας αντίστροφης όσμωσης επιτυγχάνεται με δύο τρόπους. Ο πρώτος είναι ο συνδυασμός της μονάδας με ένα σύστημα φωτοβολταϊκών το οποίο θα είναι τοποθετημένο στη περιοχή των Πατρών. Ο δεύτερος είναι ο συνδυασμός της μονάδας με ένα σύστημα ανεμογεννητριών σε περιοχή όπου υπάρχει κατάλληλο αιολικό δυναμικό. Η πειραματική μελέτη της ηλιακής απόσταξης έγινε αξιολογώντας τη λειτουργία ενός απλού ηλιακού αποστακτήρα μονής βαθμίδας. Ο αποστακτήρας που δημιουργήσαμε και τοποθετήσαμε στη ταράτσα του κτηρίου του τμήματος φυσικής , πανεπιστημίου Πατρών, υπόκειται σε μία σειρά πειραμάτων όπως: • Η επίδραση της έντασης της ηλιακής ακτινοβολίας στην παραγωγικότητα και στην απόδοση και του αποστακτήρα. • Η επίδραση της αρχικής ποσότητας του νερού που βρίσκεται στον αποστακτήρα στην παραγωγικότητα και στην απόδοση του αποστακτήρα. / The aim of this thesis is the description and the economic evaluation of a seawater desalination plant which is energy independent, and the experimental study of the solar distillation’s method. The desalination plant described is a reverse osmosis unit and the description was made by using a membranes’ software design and simulation. Our aim is to examine the energy requirements of this unit function parameters such as the quality of the feed water, the type and number of membranes and productivity. The energy independence of the reverse osmosis unit is achieved in two ways. The first way is a combination between the unit and a photovoltaic system, which will be located in the area of Patras. The second way is a combination between the unit and a turbine system in an area where there is a suitable wind resource. The experimental study of solar distillation took place through the evaluation of a simple solar distiller. This distiller, which was placed on the roof of the Physics Department of the University of Patras, is subject to a series of experiments such as: •The effect solar radiation has on the productivity and efficiency of this particular solar distiller •The effect the initial amount of water, which is found in this solar distiller, has on the productivity and efficiency of its solar distiller

Made available in DSpace on 2016-08-31T13:15:03Z (GMT). No. of bitstreams: 1 AndreMO_DISSERT.pdf: 1092497 bytes, checksum: 58516c6688820fdb0dbf9a4c3e12b9a2 (MD5) Previous issue date: 2011-03-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The brackish waters may represent a great potential in agricultural production profitable, depending on the adoption of proper cultural practices and the crop tolerance to salinity. Hydroponic systems can contribute to the production of vegetables when you use lower quality water, because the saturation state of the plants are subjected, enables increased tolerance of the same salinity. However, studies to be conducted in order to increase information about the use of brackish water in hydroponic systems, and also looking for information on levels of crop response to salinity are of fundamental importance to improve investment yields in hydroponics, especially in the Northeast Brazil. Given the lack of information for the crops of melons and tomatoes hydroponically, the objective was to investigate the potential use of brackish water and desalinator in such cultures. Two experiments were conducted with two melons and tomatoes in open hydroponic system in the greenhouse of the Universidade Federal Rural do Semi-arido (UFERSA) in Mossoró-RN. We evaluated the melon (Cucumis melo L.), cantaloupe, the AF 015, in terms of growth and production, the first experiment using saline waste with different levels of salinity throughout the cycle, and the second experiment the melon crop exposed to salt stress at different stages. The third and fourth experiments the culture was evaluated tomato (Lycopersicon esculentum L.), cherry, and tomato cultivar Fern Group Santa Cruz, Kada Gigante cultivar, respectively, using water desalinator in the nutrient solution in different dilutions, and latter at different stages of implementation. We used three different sources of water. The drinking water came from the public supply system that supplies the campus UFERSA. The brackish water was obtained from deep artesian well located in the Departmento de Ciências Ambientais of UFERSA. Already the desalination reject water was collected in the community Puxa Boi, located in Mossoró, RN. For the four experiments, we used a hydroponic system equipped with pots filled with coconut fiber, in which each vessel representing a separate plot. The application of brackish water and desalinator the nutrient solution of higher electrical conductivity, caused reductions in the growth and production of both the melon and tomato, but with no death of plants, showing the strength of the same water salinity this cropping system. It was also observed that at lower levels of salts, ie at higher dilutions with water supply, little or no significant difference was observed in the data collected. What can be considered as a viable alternative to the use of lower quality water when applied at dilutions of nutrient solution via hydroponic cultivation. / As águas salobras podem representar grande potencial na produção agrícola rentável, dependendo da adoção de práticas culturais adequadas, bem como da tolerância da cultura à salinidade. Os sistemas hidropônicos podem contribuir na produção de hortaliças quando se utiliza água de qualidade inferior, pois o estado de saturação que as plantas estão submetidas, possibilita o aumento da tolerância das mesmas à salinidade. Contudo, estudos a ser realizados visando o aumento de informações sobre o uso de águas salobras em hidropônia, e também buscando informações sobre os níveis de resposta das culturas a salinidade, são de fundamental importância para aperfeiçoar os investimentos em produções hidropônicas, principalmente na região nordeste do Brasil. Tendo em vista a falta de informação para as culturas do melão e tomate hidropônico, o objetivo deste trabalho foi averiguar o potencial de utilização de águas salobras e de rejeito de dessalinizador em tais culturas. Foram realizados dois experimentos com melão e dois com tomate, em sistema hidropônico aberto dentro de casa de vegetação no Campus da Universidade Federal Rural do Semi-árido (UFERSA) em Mossoró-RN. Foi avaliado o comportamento do meloeiro (Cucumis melo L.) do tipo cantaloupe, cultivar AF 015, sob os aspectos de crescimento e produção, sendo o primeiro experimento utilizando rejeito salino com diferentes níveis de salinidade, ao longo de todo o ciclo, e o segundo experimento a cultura do melão exposta a condições de estresse salino em diferentes estádios. O terceiro e quarto experimentos a cultura avaliada foi o tomate (Lycopersicon esculentum L.) do grupo cereja, cultivar Samambaia e o tomate do grupo Santa Cruz, cultivar Kada Gigante, respectivamente, utilizando água de rejeito de dessalinizador na solução nutritiva em diferentes diluições, sendo este último em diferentes épocas de aplicação. Foram utilizadas três fontes diferentes de água. A água potável era proveniente do sistema de abastecimento público que abastece o campus da UFERSA. A água salobra, era obtida do poço artesiano profundo localizado no Departamento de Ciências Vegetais da UFERSA. Já a água de rejeito do dessalinizador era coletada na comunidade Puxa Boi, localizada em Mossoró, RN. Para os quatro experimentos realizados, utilizou-se um sistema hidropônico dotado de vasos preenchidos com fibra de coco, em que cada vaso representava uma parcela independente. A aplicação de água salobra e de rejeito de dessalinizador na solução nutritiva de maiores condutividades elétricas, provocou reduções nos parâmetros crescimento e de produção, tanto do melão quanto do tomate, contudo sem haver morte de plantas, evidenciando a resistência das mesmas a salinidade da água nesse sistema de cultivo. Foi observado, também, que nos menores níveis de sais, isto é, nas maiores diluições com água de abastecimento, pouco ou quase nenhuma diferença significativa foi observada nos dados coletados. O que pode ser considerado como alternativa viável na utilização das águas de qualidade inferiores quando aplicadas em diluições de solução nutritiva via sistema hidropônico de cultivo.

L'électrodialyse peut être utilisée pour traiter des effluents salins contenant de la matière organique. La compréhension des mécanismes de transfert (eau, ions, espèces organiques) à travers les membranes échangeuses d'ions et particulièrement l'influence de la composition ionique est un point clé vis-à-vis des performances du procédé. L'objectif de cette thèse est l'étude du transfert et la relation avec les performances de dessalement. Les nombres d'hydratation des ions sont tout d'abord calculés à partir des mesures du transfert des ions et de l'eau. Ils sont indépendants du courant et de la composition saline. La comparaison avec des valeurs de la littérature montre que les membranes ont peu d'effet sur l'hydratation des ions. Le transfert d'espèces organiques est ensuite étudié pour différentes compositions salines. Outre la diffusion, une contribution additionnelle est mise en évidence (convection pour les espèces neutres, migration pour les espèces chargées). Pour les espèces neutres, diffusion et convection sont du même ordre de grandeur et fixées par l'effet stérique. Des tendances inverses sont obtenues concernant l'hydratation des ions, la diffusion étant limitée par les modifications des membranes, la convection étant limitée par l'hydratation des espèces organiques en solution. Pour les espèces chargées, la migration domine la diffusion, les deux contributions étant influencées par la présence de sel. Les performances de dessalement sont enfin discutées sur la base d'un modèle phénoménologique à 4 paramètres liés au transfert de l'eau, des ions et des espèces organiques. La robustesse du modèle est validée pour différentes conditions. Ce travail montre que l'électrodialyse est une technologie très prometteuse pour le dessalement d'effluents contenant de la matière organique. / Electrodialysis can be used to treat saline water containing organic solute, separating organic solutes from salt. The understanding of salt, water and organic solute transfer through ion- exchange membranes and especially the influence of salt composition is a key factor regarding the process performances. The aim of the Thesis is to investigate the mass transfer and the relationship with the desalination performance. Firstly, hydration numbers of individual ion transferring through the membranes are computed based on experimental measurements of ion- water flux. They are independent from the salt compositions and current. Comparison with literatures values shows that the membranes have a weak influence on the ion hydration. Secondly, the transfer of different organic solutes is investigated with different salt compositions. Two contributions are pointed out, diffusion and additional one (convection for neutral solute, migration for charged one). For neutral solutes, diffusion and convection are comparable and both fixed by steric effect. Ion hydration leads to reversed trend for diffusion due to membrane swelling and convection due to solute dehydration. For charged solute, migration is more important than diffusion, both being influenced by the presence of salt. Then, desalination performance is discussed based on a phenomenological model, consisting of 4 parameters, related to ion, water and organic solute transfer respectively. The robustness of the model is demonstrated for different conditions. This work shows that electrodialysis can be a very promising process for the desalination of saline water containing organic solutes.

O crescimento da populaÃÃo mundial e a crescente demanda de Ãgua para atender o consumo das famÃlias e os demais setores da economia, tÃm despertado para o aproveitamento de fontes alternativas ou Ãguas de qualidade inferior, tais como as Ãguas salinas e residuÃrias. O objetivo desse trabalho foi realizar uma avaliaÃÃo preliminar sobre a situaÃÃo dos dessalinizadores instalados pelo Governo do Estado do Cearà na regiÃo de Pentecoste, CearÃ, e, em seguida, avaliar estratÃgias de manejo da irrigaÃÃo (uso cÃclico de Ãgua salina, mistura de fontes de Ãgua de diferentes salinidades e utilizaÃÃo apenas nos estÃdios de maior tolerÃncia da cultura) e o sistema de rotaÃÃo de culturas feijÃo-de-corda/girassol, visando o uso sustentÃvel de Ãgua salina na agricultura irrigada. O experimento com feijÃo-de-corda foi conduzido no campo na estaÃÃo seca de 2011, e obedeceu ao delineamento em blocos ao acaso, com treze tratamentos e cinco repetiÃÃes. Os tratamentos consistiram de: T1: Ãgua de baixa salinidade (A1), durante todo o ciclo; T2, T3 e T4: Ãgua com CE de 2,2 (A2), 3,6 (A3) e 5,0 (A4) dS m-1, durante todo o ciclo, T5, T6 e T7: Ãgua com CE de 2,2, 3,6 e 5,0 dS m-1 na fase final do ciclo, T8, T9 e T10: Uso cÃclico de A1 e A2; A1 e A3 e A1 e A4, iniciando com A1 no plantio; T11, T12 e T13: Ãgua com CE de 2,2, 3,6 e 5,0 dS m-1 11 dias apÃs o plantio atà o final do ciclo, respectivamente. Para verificar o efeito residual de Ãgua salina aplicada durante o experimento com o feijÃo-de-corda, foi cultivado na estaÃÃo chuvosa de 2012 o girassol nas mesmas parcelas que foram cultivadas com o feijÃo-de-corda, utilizando irrigaÃÃo suplementar com Ãgua de baixa salinidade (A1). Os valores de CEa para o rejeito de dessalinizaÃÃo na regiÃo de Pentecoste variaram de 4,2 a 7,6 dS m-1, representando riscos para o ambiente, sendo que a maior parte do rejeito gerado à utilizada para alimentaÃÃo animal e a grande maioria da populaÃÃo nÃo tem conhecimento se o rejeito causa algum dano à saÃde humana ou ao meio ambiente. Os resultados dos experimentos de campo demonstraram que a aplicaÃÃo de Ãgua salina durante todo o ciclo do feijÃo-de-corda ao nÃvel de 5,0 dS m-1 e apÃs a 11 dias do plantio atà o final do ciclo inibe as trocas gasosas foliares, a extraÃÃo de nutrientes, o crescimento vegetativo e a produtividade da cultura, enquanto as estratÃgias de irrigaÃÃo com Ãgua salina na fase final do ciclo (floraÃÃo e frutificaÃÃo) e de forma cÃclica nÃo afetam de forma negativa essas variÃveis. AlÃm disso, essas estratÃgias permitiram uma economia de 34 a 47% de Ãgua de baixa salinidade utilizada na irrigaÃÃo. Ocorreu acÃmulo de sais no solo durante o cultivo do feijÃo-de-corda nos tratamentos em que se utilizou Ãgua de elevada salinidade. No entanto, o uso de estratÃgias de manejo como a aplicaÃÃo alternada de Ãguas de baixa e alta salinidade ao longo do ciclo da cultura e aplicaÃÃo da Ãgua salina apenas no estÃdio final reduziu o impacto sobre o solo. A irrigaÃÃo com Ãgua do canal (A1) com CE de 0,5 dS m-1 durante o cultivo do girassol promoveu a lixiviaÃÃo do excesso de sais no solo no final do cultivo, mas o total de chuvas antes do plantio nÃo foi suficiente para eliminar completamente o efeito residual da salinidade nesta cultura. / The world population growth and increasing demand for water to meet household consumption and other sectors of the economy, have awakened for the use of alternative sources or water of inferior quality, such as saline water and wastewater. The aim of this study was a preliminary assessment of the situation of desalination plants installed by the State Government of Ceara in the region of Pentecoste, CearÃ, and then to evaluate irrigation management strategies (cyclic use of saline water, mixture of water of different salinities and use only in stages of tolerant phase of crop) and the system of crop rotation cowpea/sunflower, aiming at the sustainable use of saline water in irrigated agriculture. The experiment with the cowpea was conducted in the dry season of 2011, and followed the randomized block design, with thirteen treatments and five replications. The treatments were: T1: low salinity water (A1), throughout the cycle, T2, T3 and T4: Water with CE 2.2 (A2), 3.6 (A3) and 5.0 (A4) dS m-1, throughout the cycle, T5, T6 and T7: Water with EC of 2.2, 3.6 and 5.0 dS m-1 in the final phase of the cycle, T8, T9 and T10: Use cyclic A1 and A2, A1 and A3 and A1 and A4, starting with A1 at sowing, T11, T12 and T13: Water of EC of 2.2, 3.6 and 5.0 dS m-1 after germination until the end of cycle. To verify the residual effect of saline water applied during the experiment with the cowpea, sunflower was grown in the rainy season of 2012 in the same plots that were cultivated with cowpea, using supplementary irrigation with water of low salinity. The EC of the desalination waste in the region of Pentecoste ranged from 4.2 to 7.6 dS m-1, representing a risk for the environment, where much of the waste generated is used to feed the vast majority of population is not aware if the reject cause any harm to human health or to the environment. The results of field experiments showed that the use of saline water during the entire cycle of the cowpea up to the level of 5.0 dS m-1 and after germination until the end of the cycle inhibits leaf gas exchange, extraction of nutrients, plant growth and crop yield, while the strategies of irrigation with saline water in the final phase of the crop cycle (flowering and fruiting) and cyclically not negatively affect these variables. Further, these strategies allow a saving 34-47% water of low salinity used for irrigation. There was accumulation of salts in the soil for the cultivation of cowpea of the treatments which used water of high salinity. However, the use of strategies for managing the application of alternating high and low water salinity crop cycle and application of the salt water only in the final stage reduced the impact on soil. The irrigation water of low salinity (0.5 dS m-1) promoted excessive leaching of salts in the soil at the end of sunflower cultivation, but the amount of rainfall before seeding was not sufficient to completely eliminate the residual effect of salinity in the crop.

No presente trabalho foram avaliados processos alternativos de dessalinização visando a recuperação e reuso da água contida em salmouras concentradas, sendo o processo de cristalização assistida por destilação por membranas (MDC) investigado com profundidade. Foi desenvolvido um modelo diferencial para o processo de destilação por membranas por contato direto (DCMD), contemplando métodos termodinâmicos rigorosos para sistemas aquosos de eletrólitos fortes, bem como mecanismos de transferência de calor e massa e efeitos de polarização de temperatura e concentração característicos deste processo de separação. Com base em simulações realizadas a partir do modelo matemático assim desenvolvido, foram investigados os principais parâmetros que influenciam o projeto de um módulo de membranas para DCMD. O modelo foi posteriormente estendido com equações de balanço de massa e energia adicionais para incluir a operação de cristalização e desta forma representar o processo de MDC. De posse dos resultados das simulações e do modelo estendido, foi desenvolvido um método hierárquico para o projeto de processos de MDC, com o objetivo de conferir características de rastreabilidade e repetibilidade a esta atividade. Ainda a partir do modelo MDC foram discutidos aspectos importantes em MDC como a possibilidade de nucleação e crescimento de cristais sobre a superfície das membranas, bem como o comportamento do processo com sais com diferentes características de solubilidade e largura da zona metaestável. Verificou-se que para sais cuja solubilidade varia muito pouco com a temperatura e que possuem zona metaestável com pequena largura, caso do NaCl, a operação com resfriamento no cristalizador não é viável pois aumenta excessivamente o consumo energético do processo, sendo nesses casos preferível a operação \"isotérmica\" - sem resfriamento no cristalizador - e o convívio com a possibilidade de nucleação no interior do módulo. No extremo oposto, observou-se que para sais com grande variabilidade da solubilidade com a temperatura, um pequeno resfriamento no cristalizador é suficiente para garantir condições de subsaturação no interior do módulo, sem grande ônus energético para o processo. No caso de sais com pequena variabilidade da solubilidade com a temperatura, mas com largura da zona metaestável elevada, existe certo ônus energético para a operação com resfriamento do cristalizador, porém não tão acentuado como no caso de sais com zona metaestável estreita. Foi proposto um fluxograma alternativo para o processo de MDC, onde foi introduzido um circuito de pré-concentração da alimentação antes do circuito de cristalização, para o caso de alimentação com soluções muito diluídas. Este esquema proporcionou um aumento do fluxo permeado global do processo e consequentemente uma redução na área total de membrana requerida. Verificou-se que através do processo com préconcentração da alimentação de 5% até 10% em massa - no caso de dessalinização de uma solução de NaCl - foi possível reduzir-se a área total da membrana em 27,1% e o consumo energético específico do processo em 10,6%, quando comparado ao processo sem pré-concentração. Foram desenvolvidas ferramentas úteis para o projeto de processos de dessalinização por MDC em escala industrial. / Alternative desalination processes aiming at the recovery and reuse of the water contained in concentrated brines were evaluated, being the membrane distillation crystallization (MDC) process investigated in depth. A differential model for the direct contact membrane distillation (DCMD) process was developed for that matter, comprising rigorous thermodynamic methods for strong electrolytes, heat and mass transfer mechanisms and temperature and concentration polarization effects. Based on simulations from the mathematical model thus developed, the main parameters that influence the design of DCMD membrane modules were investigated. The model was further extended with mass and energy balance equations in order to consider the crystallization unit operation and thus suitably represent the MDC process. Based on the simulations results and the extended model, a hierarchical method was developed for the MDC process design, adding traceability and repeatability characteristics to the design activity. Important aspects of the MDC process such as the possibility of nucleation and crystal growth on the membrane surface, as well as the behavior of the process with salts presenting different solubility characteristics and metastable zone widths were further discussed. It was observed that salts presenting negligible temperature dependence regarding their solubility and small metastable zone widths (i.e. NaCl) do not favor the operation with cooling in the crystallizer due to excessive increase in energy consumption, being the isothermal operation more indicated in such cases even at the risk of nucleation inside the membrane module. On the other hand, it was noticed that for salts whose solubility is highly temperature dependent a slight cooling in the crystallizer is enough to assure subsaturated conditions inside the membrane module with minimal energy consumption increase. In the case of salts with low temperature dependence regarding solubility but with large metastable zone widths, the operating strategy of applying cooling in the crystallizer may increase energy consumption but not as significantly as in the case of salts with small metastable zone widths. An alternative flowsheet for the MDC process was proposed, where a pre-concentration loop was introduced before the crystallization loop, showing good results for dilute feeds since it takes advantage of the higher water activity and consequently higher transmembrane fluxes due to the lower concentration. It was perceived a 27.1% reduction in the required membrane surface and a 10.6% energy consumption reduction for the modified flowsheet with the pre-concentration loop, for a feed comprised of 5% of NaCl. Useful tools aimed for the design of industrial scale processes based on MDC were developed.

<div> Here, the quartz crystal microbalance with dissipation monitoring (QCM-D) is employed to explore the interaction of the various free oxidant species with condensed PA model membranes in order to improve our understanding of how the interaction with these species affects rates of membrane chlorination and alter membrane structure. Molecular-scale mass uptake and changes in the dissipative nature of the of the model membranes as measured by the QCM is correlated to performance changes in interfacially polymerized PA reverse osmosis (RO) membranes. Leveraging newly gained insights from these measured interactions, new strategies are explored to improve flux and chlorine resistance using novel membrane structure and chemistry.<br></div>

Capacitive deionization technologies have gained significant attention in recent years. The development and availability of a variety of materials have enabled the growth of research on electrosorption, which makes capacitive deionization increasingly attractive. This technology has a wide range of applications, such as softening, desalination and selective removal, each of which has been the focus of the experimental part of this work. The theoretical part is devoted to the issue of functioning of capacitive deionization, electrode material and especially the specific application. Water desalination is a major issue, given the global shortage of drinking water and the possibility of using capacitive deionization as a competitive method to conventional desalination methods. Conversely, softening and selective removal of ions can pose everyday problems both in the treatment of drinking water or pre-treatment of industrial water and in the treatment of wastewater. In this diploma thesis, it was proved that the method of capacitive deionization can be used to solve all the above problems. Although capacitive deionization is not a commercially available technology in the Czech Republic yet, it can be expected to be used more and more in the future.

Dewatering and desalination of building constructions is currently a discussed topic. At the present time, different techniques for dewatering and desalination can be used. The existing methods are efficient but it is necessary to improve these methods and to develop new ones. The moisture in the building constructions is directly connected with the salts, which can be dissolved in it and together with the moisture further to move. The salts can cause damage of constructions and change mechanical and physical properties of the buildings materials. The basic demands for dewatering and desalination are the speed, efficiency and economical factors. Presented dissertation focuses on dewatering and desalination with the use of electrokinetic methods together with the technique of the clay poultices. In the first part of the thesis, basic theoretical principles of moisture and salts are described. In the second part (experimental part), the series of experimental measurements were conducted both in the laboratory and in situ. In this part of dissertation, I was dewatering and desalinating bricks and sandstones under an applied electric field. The main focus was on the optimization of a laboratory setup in order to get the highest efficiency for dewatering and desalination. Other measurements were done in situ, where the same technique was used.