Water recycling by membrane treatment is widely accepted as a leading alternative water source. This separation process creates a concentrated stream (called concentrates), containing most of the pollutants in 10%-20% of the flow; and a treated water stream. As nitrogen is a major concern, environmental regulations have become more stringent, requiring additional treatment to meet effluent standards. Other concerns include organic contaminants and potential production of halogenated organics if disinfection of the reject was applied. One option to address the problem of dissolved organic nitrogen and carbon is advanced oxidation. This oxidation could lead to degradation of refractory organic materials, which are poorly removed in conventional treatment. This project aims to evaluate treatment extent and cost of alternatives for organic (particularly nitrogen) removal in reject water addressing the following research gaps: (i) identifying the key organic pollutants present in the concentrated stream, (ii) the effectiveness and optimisation of coagulation, ion exchange and advanced oxidation; (iii) apparent cost of the different treatment methods. The untreated reverse osmosis concentrates were collected from two treatment plants:- Luggage Point, and Bundamba, both near Brisbane, Queensland, Australia. The first contains more colourful of organics than the second plant. Stirred cell fractionation with ultrafiltration membranes was used to characterise the removed key pollutants, as it offers better accuracy and reproducibility compared to centrifugation fractionation. Fluorescence spectral was used to monitor and identify specific organic compounds. The largest fraction was smaller sized <1kDa. This is probably small humic substances and fulvic acids, as indicated by Excitation Emission Matrix (EEM) analysis. A smaller portion of soluble microbial products (SMPs) also contributes to the concentrates. Bundamba contains large non coloured organics including organic nitrogen with elevated ammonia-N. In contrast, Luggage Point has higher colour, inorganic carbon and conductivity with less ammonia-N. Advanced Oxidation Process (AOP) was the most effective treatment method (high removal of organics, e.g. 55% COD of initial), followed by magnetised ion exchange (MIEX) and coagulations. For UV/H2O2 AOP, the optimal operating condition 400mg.L-1 H2O2 and 3.1kWh.m-3 energy input resulted in organics removals up to 55% with complete decolourisation. The effective reduction was found in all size ranges, preferably in >1kDa. Low inorganic carbon and salinity in Bundamba may allow better overall oxidation rates. MIEX also performed better in Bundamba with organic removals up to 43% and 80% decolourisation at the optimum resin dose of 15mL.L-1. Removal was preferential in size range of >3kDa, with more proportional percentage for decolourisation. Similarly, ferric coagulation removed a wider size range of organics. Further, ferric achieved better organic removal in Luggage Point with up to 49%. At the same molar dose (1.5mM), ferric is superior to alum, especially in Bundamba where there were less hydrophobic compounds according to EEM. Alum is poor for treatment of high organics with less coloured water. MIEX with an operational cost (chemicals and power only) of $0.14-$0.20.m-3 treated water seemed to be the most effective treatment overall. The resin achieved better results with a slightly higher cost than coagulation, and had a lower environmental impact due to reduced sludge production. AOP offers better treatment, but at a higher cost ($0.47.m-3 treated). Combined alternatives may benefit the removal effectiveness. Furthermore, more specific identification of contaminants should be investigated separately to choose appropriate treatment for priority chemicals. Another issue is further investigation of costing, including capital, and full environmental impact of treatment.

Thesis (Master of Engineering in Chemical Engineering))--Cape Peninsula University of Technology, 2018. / Fresh, clean water has always been critical for the world's social development. Supply of water can be reinforced through recycling and reuse; and secondary treatment of municipal wastewater effluent with a membrane bioreactor (MBR) followed by a reverse osmosis (RO) process, has emerged as a crucial treatment process for water reuse. However, fouling of RO membranes in such process is unavoidable. This leads to poor performance, increase in operational cost and degradation of the membrane material, which reduces the membrane life span. Various researches have been conducted to provide an understanding of the mechanism of fouling, and methods have been developed to minimize it. In this research, the effect of surface modification to minimise fouling on a thin film composite polyamide RO membrane was investigated. This study was divided into three parts, namely: membrane modification, biofouling and filtration using RO. Two modifying agents, PVA and DMAEMA, were used as grafting solutions. Escherichia coli (E. coli) were used as the biofoulant to study the ant-biofouling properties of the membranes. A make-up synthetic MBR secondary effluent feed was used in a bench scale RO process. During the membrane modification process, the membrane was treated using two different approaches. Firstly, the covalent attachment of polyvinyl alcohol (PVA) through Glutaraldehyde (GA) onto the surface and secondly the redox initiated grafting of dimethyl amino ethyl methacrylate (DMAEMA PVA and DMAEMA grafting solutions were applied at four different concentrations). The PVA and DMAEMA modifying agents were successfully grafted onto the membrane top layers and were confirmed by the functional groups, present, using the Attenuated Total Reflectance–Fourier Transform Infrared spectroscopy (ATR-FTIR) spectra. The morphology of the membrane surfaces was investigated using Scanning Electron Microscopy (SEM), before and after treatment. SEM analysis showed better membrane structures with PVA grafting compared to DMAEMA.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-10-18T12:30:31Z No. of bitstreams: 1 ADEMIR MORAIS DE MEDEIROS - DISSERTAÇÃO (PPGEQ) 2017.pdf: 3204134 bytes, checksum: c8135684c13cdcbef03ebfe63c7a1c99 (MD5) / Made available in DSpace on 2018-10-18T12:30:31Z (GMT). No. of bitstreams: 1 ADEMIR MORAIS DE MEDEIROS - DISSERTAÇÃO (PPGEQ) 2017.pdf: 3204134 bytes, checksum: c8135684c13cdcbef03ebfe63c7a1c99 (MD5) Previous issue date: 2017-10-30 / Capes / A dessalinização é um processo bastante difundido e utilizado no mundo para o tratamento de águas de diversas fontes hídricas as quais necessitam de tratamento para tornar-se potável e assim promover a segurança hídrica e a manutenção da vida, embora pouco utilizada na proporção necessária, a dessalinização de águas no Nordeste Brasileiro vem se tornando uma técnica bastante requisitada devido sua eficiência no tratamento de águas. O objetivo desta pesquisa foi avaliar a qualidade do permeado de um sistema hibrido de membranas para fins de dessalinização de águas salobras com a remoção do gás carbônico por uma torre de resfriamento, avaliando o desempenho do processo de separação por membrana para tratamento de águas através de estudo avaliativo dos dados reais com os simulados ambos para o permeado da OI. Os dados teóricos são os resultados obtidos a partir de análises reais realizadas nas águas do presente trabalho, inseridos no SOFWARE ROSA® 8.0.3 e realizada as simulações. No presente trabalho utilizou-se a membrana polimérica de Osmose Inversa (BW30 4040) na simulação e nos experimentos de bancadas. A partir da simulação foi possível ajustar as pressões de operação para os seguintes valores: 6, 9, 11, e 13 bar, para água de superfície e 13 e 15 bar para água de poço. Avaliou-se a rejeição de sais (%RS) obtendo valores próximos de 98 % para o permeado. Estudou-se por meio de uma torre de resfriamento como um pós-tratamento, a remoção de CO2 que apresentou como efeito, a diminuição do pH do permeado. Verificou-se através de análises que após a torre de ocorreu uma remoção parcial média de dióxido de carbono de cerca 75 %. / Desalination is a widely used process in the world for the treatment of water from a variety of water sources, which requires treatment to become potable and thus promote water safety and life-support, although little used in the necessary proportion, to desalination of water in the Brazilian Northeast has become a highly requested technique due to its efficiency in water treatment. The objective of this research was to evaluate the permeate quality of a hybrid membrane system for desalination of brackish water with the removal of carbon dioxide by a cooling tower, evaluating the performance of the membrane separation process for water treatment through evaluation of the real data with the simulated ones for the RO permeate. Theoretical data are the results obtained from real analyzes performed in the waters of the present work, inserted in SOFWARE ROSA® 8.0.3 and the simulations were performed. In the present work the polymer membrane of Reverse Osmosis (BW304040) was used in the simulation and bench experiments. From the simulation it was possible to adjust the operating pressures to the following values: 6 bar 9 bar, 11bar, and 13 bar for surface water and 13 bar and 15 bar for well water. The salt rejection (% SR) was evaluated, obtaining values close to 98% for the permeate. It was studied by means of a cooling tower as a post-treatment, the removal of CO2 that had as effect, the decrease of the pH of the permeate. It was verified through analyzes that after the tower a mean partial removal of carbon dioxide of about 75% occurred.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-14T11:45:03Z No. of bitstreams: 1 ARLEIDE RICARTE DE OLIVEIRA - TESE (PPGEP) 2007.pdf: 4819651 bytes, checksum: 1cc38913961211c387807eb81998c764 (MD5) / Made available in DSpace on 2018-09-14T11:45:03Z (GMT). No. of bitstreams: 1 ARLEIDE RICARTE DE OLIVEIRA - TESE (PPGEP) 2007.pdf: 4819651 bytes, checksum: 1cc38913961211c387807eb81998c764 (MD5) Previous issue date: 2007-08-31 / Capes / A falta de água potável em algumas localidades do mundo, mais precisamente no semi-árido, é um problema de caráter secular, agravado pela poluição, distribuição irregular e existência de águas subterrâneas de utilização bastante limitada por causa dos altos índices de salinidade. Por outro lado, essas regiões possuem um grande potencial de irradiação solar que favorece a utilização de painéis fotovoltaicos, principalmente em locais distante da rede elétrica. Visando melhorar a qualidade de vida e minimizar o problema da falta de água potável nessas regiões, esse trabalho tem como objetivo estudar o desempenho de um protótipo de equipamento para fins de dessalinizar águas salobras via osmose inversa, fazendo uso de um gerador fotovoltaico com a utilização de um circuito eletrônico, no qual substitui acumuladores de carga (baterias). Com o uso do circuito eletrônico foi possível produzir água potável sem a necessidade da utilização de acumuladores de carga (baterias) e sem danificar o motor-bomba. A ausência do banco de baterias proporciona uma redução dos custos e da necessidade de manutenção; mas o sistema torna-se subordinado às condições instantâneas da radiação solar e da temperatura ambiente. Esse sistema foi instalado no Laboratório de Referência em Dessalinização (LABDES), na Universidade Federal de Campina Grande. O desempenho do sistema foi avaliado com soluções de cloreto de sódio com concentração de 1.000 mg/L e 2.500 mg/L e água de poço com concentração de 3.800 mg/L. As variáveis de medidas, como: tensão, corrente, vazão e pressão foram obtidas em tempo real no Software Data Aquisition, através de sensores elétricos. A partir desses dados foram avaliados os seguintes parâmetros: potência elétrica, vazão do permeado e do concentrado, recuperação e consumo de energia por m3 de água produzida. As condições meteorológicas e as concentrações da água de alimentação influenciam diretamente na pressão, e consequentemente na produção de água. Mesmo com a grande variação de tensão em função da irradiação solar, o sistema mostrou condições técnicas de produzir 0,25 m3/h de água dessalinizada. A pressão máxima obtida foi de 8,2 kgf/cm2. O balanço econômico, que representa o custo-benefício de implantação, operacional e manutenção para atender comunidades isoladas, mostrou que o menor custo de água dessalinizada é obtido quando o sistema de dessalinização é instalado em localidade na qual já possui o poço tubular e um local para servir de abrigo para o sistema de dessalinização. Para essas localidades é viável o uso de painéis fotovoltaicos. / The lack of drinking water in some places of the world, more precisely in the semi-arid region of Brazil, is an old problem, worsened by the pollution, irregular distribution and high salinity of underground waters. On the other hand, those areas possess a great solar irradiation rate that favors the use of photovoltaic panels, mainly where the electric net is not available. Seeking to improve the life quality and to minimize the problem of the lack of drinking water in those areas, the objective of this work is to study and evaluate an osmosis reverse desalination system, using photovoltaic solar energy coupled to an electronic circuit. This electronic circuit replaces the use of batteries without damaging the motor-bomb. The absence of batteries provides a reduction of the cost and maintenance need; but the system is subordinated to the instantaneous conditions of the solar radiation. This system was installed at the Reference Laboratory of Desalination (LABDES) in the Federal University of Campina Grande. The system was evaluated with sodium chloride solutions of 1,000 and 2,500 mg/L NaCl concentrations, and a well water of 3,800 mg/L TDS concentration. The meteorological conditions and the concentrations of the feeding water influence directly the applied pressure and consequently the permeate production. Even with the intermittent energy delivered by the solar photovoltaic panels, the desalination system showed good technical conditions to produce 0.25 m3/h of potable water. The economical statements , that the implantation cost-benefit represents, operational and maintenance to take care of isolated communities, showed that the lesser desalinizaded water cost is gotten when the desalination system is installed in locality in which already possesss the well and a place to serve of shelter for the desalination system. For these localities the use of photovoltaics panels is viable.

O lixiviado de aterro sanitário é um efluente complexo de alta carga orgânica, composto basicamente de substâncias recalcitrantes, amônia e poluentes tóxicos. Quando descartado de forma inadequada nos corpos receptores, desempenha um papel significativo dentre os principais fatores causadores de danos ao meio ambiente. A tecnologia de separação por membranas consiste em uma alternativa atrativa no tratamento do lixiviado, pois é capaz de remover contaminantes que não são removidos por processos de tratamento convencionais. O presente estudo tem por objetivo a avaliação, em escala de bancada, do tratamento do lixiviado por processos de separação por membranas e o monitoramento de fatores de fouling e resistências nas membranas. O sistema de membrana fibra-oca de microfiltração de poli(éter-imida) foi testado a fim de promover o polimento final do tratamento do lixiviado. O resultado obtido de remoção de matéria orgânica, expressado em DQO, variou entre 14 e 43%, no entanto, esse sistema não foi eficiente na remoção de cor. Para a remoção de cor foram realizados ensaios em sistemas de osmose inversa e de eletrodiálise, no entanto, apenas o sistema de osmose inversa apresentou resultados positivos. Foi verificado que as características do lixiviado têm influencia na formação de fouling, reduzindo o fluxo de permeado e contribuindo para o aumento das resistências. O percentual médio de fouling observado foi de 53% e a resistência da membrana contribuiu com mais de 50% da resistência total do sistema. Os resultados comprovam que a implementação do sistema de membranas de microfiltração e osmose inversa, como polimento final no tratamento de lixiviado, seriam de grande valia, tanto para atender aos padrões mínimos de lançamento de efluentes previsto na legislação brasileira como para a preservação dos recursos hídricos. / Landfill leachate is a complex wastewater of high organic matter, composed basically of recalcitrant substances, ammonia and toxic pollutants. When leachate is improperly disposed in the receiving waters, it has a significant role among the main factors causing damage to the environment. The membrane separation technology is an attractive alternative in the treatment of the leachate, because it is able to remove contaminants that are not removed by conventional treatment processes. The present study aims to evaluate, using a bench scale system, leachate treatability by membrane separation processes and to monitor fouling factors and membrane resistance. The microfiltration system of hollow fiber membrane poly(ether-imide) was tested in order to promote leachate treatment. The result of organic matter removal, expressed in COD, varied between 14 and 43%, however, this system was not efficient to color removal. Tests were performed for color removal in a reverse osmosis and electrodialysis systems, however, only the reverse osmosis system showed positive results. It was found that the characteristics of leachate have influence in the fouling formation, permeate flux reducing and contributes to the resistance increase. The average percentage of fouling observed was 53% and the membrane resistance contributed more than 50% of the total resistance of the system. The results show that microfiltration and reverse osmosis systems implementation to treat the leachate would be of great importance, both to meet the minimum standards for effluent discharge as provided for in Brazilian law to the preservation of water resources.

Os efluentes contendo cádmio podem ser gerados dos por várias indústrias. A aplicação de ambas as tecnologias osmose inversa (OI) e nanofiltração (NF) para o tratamento de efluentes contendo o íon cádmio para reduzir a degradação ambiental foram estudadas no presente trabalho. Amostras sintéticas contendo o íon cádmio em várias concentrações foram preparadas e submetidas aos tratamentos por OI e NF em escala laboratorial. Assim, dividiu-se o processo de remoção em três etapas: 1- analisou-se os processos de osmose inversa e nanofiltração em termos da rejeição do íon cádmio, onde se correlacionou e avaliou os principais parâmetros de processos (concentração da solução alimentação, fluxo de permeado e pressão) e comparou-se os sistemas entre si. Nas etapas 2 e 3 avaliou-se os efeitos da salinidade utilizando os contra-íons zinco e sódio respectivamente, sobre a rejeição do íon cádmio no sistema de osmose inversa em soluções aquosas contendo misturas de sulfato de cádmio e sulfato de zinco, e sulfato de cádmio e sulfato de sódio. Mediu-se as concentrações de cádmio e zinco por espectroscopia de absorção atômica e as concentrações de sulfato e sódio por cromatografia de íons. Os resultados obtidos na primeira etapa dos experimentos mostram que a osmose inversa e nanofiltração são eficientes na remoção de cádmio, onde se obteve as taxas médias de rejeição de 92,4% e 96,6% respectivamente, sendo esses valores iguais em magnitude, tendo em vista os valores da incerteza padrão relativa associada a esses resultados. Em ambos os sitemas, os fluxos de permeado e as rejeições não sofreram influência do aumento da concentração de cádmio na solução alimentação.Na etapa 2, os resultados mostraram a diminuição da rejeição de cádmio com o aumento da concentração de sulfato de zinco na alimentação, sendo esse fenômeno atribuído a semelhança existente entre os íons Cd2+ e Zn2+ associados aos seus raios iônicos de hidratação e as energias de hidratação. Foram observadas as quedas do fluxo de permeado e das rejeições com o aumento da concentração de alimentação provavelmente devido ao efeito da polarização. Na etapa 3, a rejeição do íon cádmio não foi afetada pelo aumento da concentração de sulfato de sódio na alimentação, assim como os fluxos de permeado. Outro aspecto relacionado à rejeição é que a difusão do sódio através da membrana é favorecida frente à difusão do cádmio, sendo atribuído ao menor raio de hidratação do sódio / Effluents containing cadmium may be produced by a variety of industries. The application of the reverse osmosis and nanofiltration technologies for the treatment of effluents containing cadmium, in order to reduce environmental degradation, were studied in the present work. Synthetic samples containing the cadmium ion in different concentrations were prepared and treated by reverse osmosis and nanofiltration. The removal process was divided in three steps: 1- the reverse osmosis and nanofiltration processes were analyzed concerning the rejection of the cadmium ion, correlating and evaluating the main process parameters (feeding solution concentration, permeated flow and pressure), and comparing the systems between themselves. In steps 2 and 3, the effects of salinity in the elimination of the cadmium ion in aqueous solutions, containing a combination of cadmium sulfate and zinc sulfate, or a combination of cadmium sulfate and sodium sulfate, were assessed by the use of zinc and sodium counterions. The concentrations of cadmium and zinc were measured by atomic absorption spectroscopy, and the concentrations of sulfate and sodium were measured by ion chromatography. The results obtained in the first step of the experiments show that the reverse osmosis and the nanofiltration processes are efficient in removing cadmium, with an average rejection rate of 92,4% and 96,6%, respectively. Considering the standard relative incertitude associated to the results, the values obtained are considered of the same magnitude. In both systems, the permeated flow and the rejects were not influenced by a rise in cadmium concentration in the feeding solution. In step 2, the results showed a decrease in cadmium rejection related with a rise in the zinc sulfate concentration in the feeding solution. This phenomenon is due to the similarity between the Cd2+ and Zn2+ ions, associated to their hydration ionic radius and to their hydration energies. A decrease in the permeated flow and of the rejects related to a rise in the feeding concentration was observed and was probably due to the polarization effect. In step 3, the cadmium ion rejection was not affected by a sodium sulphate concentration rise in the feeding, as well as in the permeated flow. Another aspect related to the rejection is that, due to its smaller hydration radius, sodium has a better diffusion rate through the membrane than cadmium

O presente trabalho avaliou a capacidade do sistema de osmose inversa de bancada na remoção de glifosato, em soluções de efluente aquoso sintético, empregando membrana de poliamida. Os parâmetros empregados para esta avaliação foram a pressão, o fluxo de alimentação, o tempo de operação, o pH e a concentração de glifosato na solução de alimentação em que os mesmos foram variados de modo a se ter um comparativo entre diferentes níveis. O sistema de osmose inversa teve em todos os experimentos uma boa resposta quanto a rejeição de glifosato em que a mesma variou entre 74,2% a 98,6 %, sendo a máxima atingida em condições de pressão em 30 bar, fluxo de alimentação 1 L.min-1 e pH 11 da solução de alimentação. A resposta do sistema foi avaliada quanto ao fluxo de permeado, de rejeição percentual e concentração de glifosato no permeado. O efeito da variação de concentração sobre a rejeição de glifosato foi pouco efetiva, mas apresentou grande influência quanto à variação de concentração deste no permeado. Ainda foi avaliada a remoção do ácido aminometilfosfônico (AMPA), pelo sistema de osmose inversa, obtendo-se uma boa resposta quanto à rejeição atingindo valores em torno de 95%. Uma solução combinada de AMPA e glifosato foi preparada e processada no sistema de osmose inversa, obtendo-se resposta similar quanto à concentração de permeado e rejeição para ambos os compostos. A quantificação de AMPA e glifosato se deu por cromatografia de íons, onde esta técnica se mostrou robusta e simples para quantificar ambos os compostos em meio aquoso, em baixas concentrações / This work evaluated the capacity of the reverse osmosis system bench in removing glyphosate from aqueous effluent synthetic solutions, employing polyamide membrane. The parameters used for this evaluation were the pressure, the feed stream, operating time, pH and concentration of glyphosate in feed solution in which they were varied in so as to have one comparison between different levels. The reverse osmosis system in all experiments had a good reply regarding rejection of glyphosate in that the same ranged between 74.2% and 98.6%, with a maximum reached under conditions of pressure 30 bar, feed stream 1 liters per minute and pH 11 of the feed solution. The system response was evaluated with respect to permeate flux, rejection and percent concentration of glyphosate in permeate. The concentration variation effect about the rejection of glyphosate was little effective, but had a great influence as to variation of the concentration in permeate. Also evaluated was the removal of aminomethylphosphonic acid (AMPA), in the reverse osmosis system, obtaining a good response regarding rejection reaching values around 95%. A combined solution of glyphosate and AMPA was prepared and processed in reverse osmosis system, obtaining a similar response regarding the concentration of permeated and rejection for both compounds. Quantitation of glyphosate and AMPA was made by ion chromatography, where the technique was demonstrated robust and easy to quantify both compounds in aqueous at low concentrations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A descarga desenfreada de águas residuais no meio ambiente, ao longo dos últimos anos, vem acelerando o processo de contaminação e degradação dos corpos hídricos no mundo. Tais rejeitos apresentam elevada carga de contaminantes e de concentração de matéria orgânica o que leva a mortandade das espécies pela concorrência ao oxigênio e, em casos extremos, a aceleração dos processos de eutrofização. Pensando nisso, o presente trabalho estudou um sistema híbrido, em batelada, de tratamento de águas oleosas simuladas em laboratório pela adição de um determinado óleo lubrificante em uma solução aquosa de agentes emulsificantes e eletrólito suporte. O sistema de tratamento foi composto de duas etapas, onde na primeira avaliou-se o uso da técnica da eletrofloculação, responsável por quebrar a estabilidade das emulsões óleo/água e de uma segunda que avaliou o uso de processos de separação com membranas visando à remoção do metal adicionado ao efluente na etapa anterior. O sistema de eletrofloculação foi avaliado em relação ao uso de eletrodos de alumínio e ferro com correntes elétricas de 1A, 2A e 3A, nos modos contínuo e alternado. Os resultados apontaram um maior consumo evidente de massa de eletrodos quando do uso da corrente contínua, 4,0337g 0,0132 para o alumínio e 3,8260g 0,0181 para o ferro ao passo que o consumo foi de 2,1400g 0,0099 para o alumínio e 2,4121g 0,0127 para o ferro quando do o uso da corrente alternada. Foram alcançadas remoções máximas de 98 % 0 da DQO, 99,77 % 0,27 de remoção da cor e 100 % 0 de remoção da turbidez para o uso de corrente alternada e eletrodos de alumínio enquanto se alcançaram remoções máximas 96 % 1 da DQO, 99,46 % 0,82 de remoção da cor e também 100 % 0 de remoção da turbidez no uso de eletrodos de ferro. Na segunda etapa do estudo, a osmose inversa, o sistema utilizado atingiu rejeições de 99,53 % 0,12; 99,56 % 0,13 e de 98,87 % 0,36, para pressões respectivas de 10, 20 e 30 bar. Além disso, foram obtidos fluxos crescentes de permeado 10,87 L/h.m2 0,25; 15,67 L/h.m2 0,53; 18,49 L/h.m2 0,74 com o também aumento da pressão. Ao final do estudo alcançou-se um efluente final com baixa carga orgânica e de metais, estando o mesmo apto ao lançamento nos corpos receptores. Entretanto, mecanismos de controle, sobretudo de pH devem ser incluídos no projeto desses sistemas uma vez que esse parâmetro sofre alterações ao longo do processo / The uncontrolled discharge of wastewater into the environment over the last years has accelerated the process of contamination and degradation of water bodies in the world. These wastes contain high amounts of contaminants and concentration of organic matter which leads to the death of several species due to lack of oxygen and, in extreme cases, acceleration of eutrophication processes. In the specific case of oily wastewater, the use of techniques such as chemical coagulation, dissolved air injection, membranes, biochemical and electrochemical processes are described. However some of these processes have limitations which range from the concentration of the contaminant in the effluent, limitations in the operating conditions and even cost constraints. With this in mind, this paper has studied a hybrid system, batch process, in the treatment of oily waters simulated in the laboratory by adding a specific lubricating oil in an aqueous solution with emulsifiers and supporting electrolyte. The treatment system was consisted of two stages, which in the first was evaluated the use of the technique of electrocoagulation, which was responsible by the breaking stability of oil/water emulsions and a second stage which evaluated the use of membrane separation processes in order to remove the metal added to the effluent in the previous stage. The electrofloculation system was evaluated in relation to the use of iron and aluminum electrodes with electrical currents of 1A, 2A and 3A, in the continuous and alternate modes. The results showed a higher apparent mass consumption of electrodes when using direct current, 4,0337 g 0,0132 for aluminum and 3,8260 g 0,0181 for iron while consumption was 2,1400 g 0,0099 for aluminum, and 2,4121 0,0127 g for the iron when the use of alternating current. Removals were reached maximum 98 % 0 COD, 99,77 % 0,27 color removal and 100 % 0 turbidity removal for use alternating current and aluminum electrodes while were reached maximum 96 % 1 of COD, 99,46 % 0, 82 color removal and also 100% 0 to remove the turbidity in the use of iron electrodes. In the second study phase, reverse osmosis, the system used has reached rejections 99,53 % 0,12, 99,56 % 0,13 and 98,87 % 0,36, corresponding to pressures of 10 , 20 and 30 bar Moreover, increasing flows were obtained permeate 10,87 L/h.m2 0,25, 15,67 L/h.m2 0,53; 18,49 L/h.m2 0,74 also with the increased pressure. At the end of the study was reached final effluent with low organic load and metals, it being able to release the bodies receptors. However, control mechanisms, particularly pH should be included in the design of such systems since this parameter changes over the process

Membrane technology can be utilised for the high purification and desalination of water. However membrane filtration processes are commonly impeded by membrane fouling, which can lead to flux decline and an overall reduction in separation efficiency within the process. Therefore the aim of this research study was a comprehensive investigation of the issue of biofouling on industrial RO membranes through molecular biology techniques, characterisation of surface charge of foulant bacteria and RO membrane surface and AFM imaging and force measurements on clean and fouled membranes for the determination of adhesion force and micromechanical properties. The laboratories within Gwangju Institute of Science and Technology, South Korea and Swansea University, Wales were equipped for the scope of this research work. Research focused on the extraction of microbial DNA obtained from fouling layers on the surface of Reverse Osmosis Membranes obtained from the Fujairah Water and Power Plant, UAE. The use of the culture independent method of the molecular technique based on the 16S rDNA sequence and constructed gene libraries, was then used to determine the bacterial species that caused significant fouling on the RO membrane. Four bacterial species isolated from the fouling layer from the RO membrane were characterised in terms of electrophoretic mobility and zeta potential to determine the cell surface charge within various industrial relevant environments for the elucidation of cell adhesion mechanisms to the membrane surface. AFM images of virgin and fouled membranes were obtained and analysed to reveal the roughness of the surface which could influence fouling and the surface charge of the membranes were measured through the method of streaming potential at various industrial relevant environments to further elucidate the mechanisms of cell adhesion to the membrane surface. Force measurements were performed to reveal the adhesion force and elasticity values of virgin, process fouled and purposely fouled with the four bacterial isolates, to determine process behaviour in various environmental conditions. Through this research and future work, it is hoped that a rational strategy for economic and effective cleaning processes will be developed which will maintain efficient membrane operation and prolong membrane life, thus enabling the reduction of operating costs of such processes.

abstract: Reverse osmosis (RO) membranes are considered the most effective treatment to remove salt from water. Specifically, thin film composite (TFC) membranes are considered the gold standard for RO. Despite TFC membranes good performance, there are drawbacks to consider including: permeability-selectivity tradeoff, chlorine damage, and biofouling potential. In order to counter these drawbacks, polyamide matrixes were embedded with various nanomaterials called mixed matrix membranes (MMMs) or thin film nanocomposites (TFNs). This research investigates the use of graphene oxide (GO) and reduced graphene oxide (RGO) into the polyamide matrix of a TFC membrane. GO and RGO have the potential to alter the permeability-selectivity trade off by offering nanochannels for water molecules to sieve through, protect polyamide from trace amounts of chlorine, as well as increase the hydrophilicity of the membrane thereby reducing biofouling potential. This project focuses on the impacts of GO on the permeability selectivity tradeoff. The hypothesis of this work is that the permeability and selectivity of GO can be tuned by controlling the oxidation level of the material. To test this hypothesis, a range of GO materials were produced in the lab using different graphite oxidation methods. The synthesized GOs were characterized by X-ray diffraction and X-ray photoelectron microscopy to show that the spacing is a function of the GO oxygen content. From these materials, two were selected due to their optimal sheet spacing between 3.4 and 7 angstroms and embedded into desalination MMM. This work reveals that the water permeability coefficient of MMM embedded with GO and RGO increased significantly; however, that the salt permeability coefficient of the membrane also increased. Future research directions are proposed to overcome this limitation. / Dissertation/Thesis / Masters Thesis Civil and Environmental Engineering 2017