Tesis:

1

Alaswad, Saleh O. M. "Investigation of organic osmotic agents forward osmosis desalination process". Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/808886/.

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This study investigated the effects of novel membrane-osmotic agent systems on forward osmosis process efficacy. Glucose, sucrose and NaCl were investigated as osmotic agents, and nano-filtration, reverse osmosis and hollow fibre flat sheet as membrane types. The effects of draw solution concentration, flow rate and temperature as well as feed water flow rate and temperature were investigated for the aforementioned membrane types. The efficacy of forward osmosis process was measured on the basis of water flux, water recovery rate, water permeability, specific energy consumption and solute flux where applicable. Single, binary and ternary systems were considered. Experimental results showed the NF membrane and the RO membrane performed better at low and high concentrations of osmotic agent. Higher water flux rates were achieved by using NF membrane for both types of osmotic agents with changing osmotic agent concentration rates. The best result was obtained through the combination of NF membrane and glucose at lower concentrations and with sucrose at higher concentrations. The NF membrane-sucrose system showed better results for all parameters when changing feed water flow rate at lower temperatures while the NF-glucose system showed better performance when increasing temperature of the solution. Specific energy consumption increased in all the combinations of membrane-osmotic agent with increasing osmotic agent concentration rates. However, the lowest energy requirements were noted for the combination of NF membrane - glucose as an osmotic agent. Overall, both NF and RO membranes showed better results at different osmotic agent flow rates, but glucose proved to be the superior osmotic agent. For the binary systems, higher FO process efficacy across almost all parameters was noted for the systems with deionised water (DW). However, systems also used more energy; because such systems also used more energy they are not necessarily superior to other systems. Water recovery rate and water flux were considerably higher in a ternary system involving sucrose + NaCl + DW compared to the ternary system using brackish water as feed solution in FO process. Overall, FO efficiency for a ternary mixture of glucose osmotic agent + NaCl salt + BW was higher in water recovery and water flux than the other ternary mixtures with DW as feed solution. Based on the study results, a number of recommendations for future work are provided. Manipulated Osmosis Desalination (MOD) is a promising desalination approach that should be further investigated by analysing the factors affecting the process’ efficacy. Such factors are likely to include various membrane parameters (thickness, porosity and different pore diameters) and draw solutions as well as the process parameters including temperature, flow rates and osmotic agent concentrations. Further investigations should be conducted for binary and especially ternary systems involving different types of membranes and solutes for refining and optimising the process of selection. The Close loop circulation system needs to be replaced by the no-circulation systems for better FO performance in future studies. Importantly, the experimental results should be compared with the developed mathematical models to further validate the results. Finally, future MOD studies should focus on identifying optimal regeneration approaches. The selection of osmotic agents based on their regeneration economics along with other important FO parameters could be undertaken in future research.

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2

Hassinger, Elaine. "Reverse Osmosis Units". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1994. http://hdl.handle.net/10150/156939.

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1 pp.
Reverse osmosis (RO) is an excellent way to remove certain unwanted contaminants, such as lead and nitrates, from your drinking water. This article discusses how reverse osmosis works, and both the advantages and disadvantages of the system.

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3

Xie, Zhangwang. "Polysaccharide fouling in reverse osmosis and forward osmosis desalination and its alleviation". Thesis, Xie, Zhangwang (2015) Polysaccharide fouling in reverse osmosis and forward osmosis desalination and its alleviation. PhD thesis, Murdoch University, 2015. https://researchrepository.murdoch.edu.au/id/eprint/31172/.

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Membrane separation processes, including forward osmosis (FO) and reverse osmosis (RO), for application in water desalination are plagued by membrane fouling. In particular, membrane biofouling is unpredictable in its nature and affected by numerous factors. One of the major contributors to biofouling is the extracellular polymeric substances (EPS) produced by bacteria, especially the polysaccharides that form a large part of EPS. The objectives of this study are to understand the polysaccharide fouling mechanisms based on a comparison of polysaccharide fouling in FO and RO and to find suitable alleviating agents for polysaccharide fouling mitigation. Three major tasks were conducted in this study. Firstly, polysaccharide fouling in FO and RO were compared under identical solution chemistry and operational conditions to understand the respective fouling mechanisms in FO and RO. Secondly, some alleviating agents for mitigation of polysaccharide fouling in FO and RO were tested to demonstrate the fouling alleviation mechanism. Thirdly, a model of hydraulic resistances was developed to illustrate membrane fouling mechanisms based on analysis of the contribution of hydraulic resistances to permeate flux decline. Major findings are: 1) Commercial polysaccharides and polysaccharides isolated from naturally adherent bacteria behaved differently in membrane fouling, which showed that alginate was not a typical model and it is important to select a proper model for polysaccharide fouling. 2) Under identical conditions, membrane fouling by both commercial and isolated polysaccharides was more severe in RO than FO, indicating the importance of pressure source in membrane fouling. 3) RO fouling was likely dominated by foulant – foulant interaction which was greatly affected by calcium ions, while FO fouling could be largely governed by foulant – membrane interaction, which was greatly influenced by solution viscosity. 4) Sodium nitroprusside (SNP) at a proper dose was found to be able to reduce membrane fouling, which could be explained by the electrostatic repulsion between polysaccharides and SNP. 5)Presence of calcium ions played a crucial role in polysaccharide fouling and its alleviation, with its presence leading to significant increase in cake resistance in RO fouling and reducing alleviation efficiency.

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4

Lion, Thomas. "Osmosis : a molecular dynamics computer simulation study". Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7877.

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Osmosis is a phenomenon of critical importance in a variety of processes ranging from the transport of ions across cell membranes and the regulation of blood salt levels by the kidneys to the desalination of water and the production of clean energy using potential osmotic power plants. However, despite its importance and over one hundred years of study, there is an ongoing confusion concerning the nature of the microscopic dynamics of the solvent particles in their transfer across the membrane. In this thesis the microscopic dynamical processes underlying osmotic pressure and concentration gradients are investigated using molecular dynamics (MD) simulations. I first present a new derivation for the local pressure that can be used for determining osmotic pressure gradients. Using this result, the steady-state osmotic pressure is studied in a minimal model for an osmotic system and the steady-state density gradients are explained using a simple mechanistic hopping model for the solvent particles. The simulation setup is then modified, allowing us to explore the timescales involved in the relaxation dynamics of the system in the period preceding the steady state. Further consideration is also given to the relative roles of diffusive and non-diffusive solvent transport in this period. Finally, in a novel modi cation to the classic osmosis experiment, the solute particles are driven out-of-equilibrium by the input of energy. The effect of this modi cation on the osmotic pressure and the osmotic ow is studied and we find that active solute particles can cause reverse osmosis to occur. The possibility of defining a new "osmotic effective temperature" is also considered and compared to the results of diffusive and kinetic temperatures.

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5

Siddiqui, Farrukh Arsalan. "Membrane filtration : fouling and cleaning in forward osmosis, reverse osmosis, and ultrafiltration membranes". Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:bcaadfaa-62fb-4910-8218-bff387a19a11.

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A comparison of fouling in osmotically driven processes with that in pressure driven processes is the main focus of the thesis. Forward osmosis (FO) and reverse osmosis (RO) have received considerable attention for water treatment and seawater desalination. This research compared the nature of fouling in FO mode with that in RO starting with the same initial flux in connection with cleaning effects and then comparing to those in ultrafiltration membranes. In all cases, with cleaning as an integral part, the extent of fouling reversibility, and the question whether a critical flux could be determined were examined. The work during the first phase (undertaken at Oxford) quantified the removal of reversible fouling through rinsing by cold and hot water for a range of concentrations using the foulants dextran and carboxymethyl cellulose. The flux-TMP relationship was conventionally compared to that of the clean water flux. The later phase (at Singapore) compared the fouling in FO and RO by alginate in terms of multiple parameters using cellulose tri acetate (CTA) and thin film composite (TFC) membranes. Silica and alginate were selected as model foulants. Whilst experimental water flux profiles in the present study did not exhibit significant differences in trend between FO and RO fouling, foulant resistance for FO was found to be increasingly greater than for RO with the progression of the fouling tests. This was further corroborated by membrane autopsies post fouling tests; both foulant mass deposition density and specific foulant resistance for FO were greater than for RO. The analysis clearly revealed that FO is essentially more prone to fouling than RO which was presumably due to less flux decline in FO (or greater average flux) as compared to that in RO in result of ICP-self compensation effect which is opposite to the prevailing claim in the literature. Additionally, the present study did not find evidence that hydraulic pressure in RO has a role in foulant layer compaction. FO membrane fouling by real waters was the focus of the final phase of the research at SMTC. Pilot scale FO experiments were conducted on spiral wound CTA membrane with treated waste water obtained from a NEWater factory (Singapore) as the feed. In the second stage, experiments were repeated at bench scale with membrane coupons taken from the spiral wound membranes used earlier. The key finding was that the mass transfer coefficients in the Spiral-Wound module were around 50% lower than the corresponding values in the flat sheet unit and this severely limited the fluxes. The reason could be attributed to strong internal concentration polarisation in the former, where tightly wound spacers act to increase the structural parameter.

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6

Guell, David Charles. "The physical mechanism of osmosis and osmotic pressure--a hydrodynamic theory for calculating the osmotic reflection coefficient". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/29859.

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7

Arnaud, Damien. "Biofouling on reverse osmosis membranes". Thesis, Arnaud, Damien (2015) Biofouling on reverse osmosis membranes. Honours thesis, Murdoch University, 2015. https://researchrepository.murdoch.edu.au/id/eprint/29838/.

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Membrane biofouling is a major concern in water treatment processes as it can significantly reduce the system’s efficiency. Biofouling is mainly caused by microorganisms, and is difficult to control or avoid. It leads to higher operating pressure which strains the membrane, shortens the membrane life, and increases maintenance costs. Multiple literature reviews suggest that the main contributors to membrane biofouling are polysaccharides. This is why in this project two model polysaccharides (alginate and xanthan) were used to study their individual fouling effects on reverse osmosis efficiency, as well as their fouling effects coupled with calcium chloride on the same system’s efficiency. During experiments, the polysaccharides were used in 0.2g/L concentrations, while calcium chloride was used at a concentration of 1.3mM. Because alginate and xanthan are two different types of polysaccharides, they would be expected to have different physical and chemical properties and thus have different fouling behaviours. It was found that the polysaccharides did not have much effect on the system’s efficiency in the absence of calcium chloride. In experiments where calcium chloride was added in the feed solution with the polysaccharide, it was demonstrated that the addition of salt led to increased membrane fouling and greater decreases in system efficiency. The fouled membranes were kept for confocal laser scanning microscopy of the fouling layers. The images determined the general structure of the cake formed on the membrane. Using the Imaris software, calculations on the average volume the cake layer was occupying (bio-volume) and the average compactness of the cake layer could be done. During experiments, the membrane showed good salt rejections with over 96% salt rejection for each experiment

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8

Suwannakarn, Monthat. "Biofouling on forward osmosis system". Thesis, Suwannakarn, Monthat (2016) Biofouling on forward osmosis system. Honours thesis, Murdoch University, 2016. https://researchrepository.murdoch.edu.au/id/eprint/33949/.

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Fouling is an inevitable issue that all membrane systems have to face. The presence of membrane fouling causes membrane systems (such as reverse osmosis and forward osmosis) to suffer the increase of resistance thus reducing the efficiency of the systems. This raises concerns about the osmosis technology as it also reduces the system and membrane lifetime while increasing the maintenance costs. From previous papers and literature review, polysaccharides were found to be the main contributor to membrane fouling. The literature explains the polysaccharides that caused the membrane fouling were alginate, BSA, AHA, xanthan and others however, only alginate and xanthan were tested in this research project. The mixing interaction of other cations such as Ca2+ with some of the aforementioned polysaccharides (salt in the form of CaCl2 and NaCl were also tested to see the changes in fouling effects when both are combined. Throughout the experiments, a fixed amount of NaCl and CaCl2 and the polysaccharide were kept constant. The draw solution (NaCl mixed with DI water) was always retained to be saturated. These experiments were designed in this way to examine the differences between each polysaccharide and its combination towards fouling behaviour, since alginate and xanthan have different chemical characteristics. The results show that xanthan causes a higher resistance compared to alginate. In the case where NaCl and CaCl2 were present in the feed solution, the resistance of both polysaccharides greatly increases thus resulting in lowering the flux and ultimately decreasing the system efficiency. Out of all the experiments, the xanthan with salt resulted in highest flux decrease while the alginate only had the least flux decline (excluding the baseline experiment). Further analysis was done using the total organic carbon (TOC) and confocal laser scanning microscopy (CLSM). These examinations demonstrated the characteristics and properties of the polysaccharide layers that were formed on the membrane surface. The CLSM result was compared with the flux and resistance movement and it was found that they supported each other (and the findings were closely related). Since CLSM analysis is able to show the x, y and z dimension, the thickness can be found within each CLSM images. Therefore the thickness of the polysaccharide (fouling) layer (from CLSM images) was thick and/or dense, the (a higher resistance was achieved) higher the resistance would be and vice versa.

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9

Zaghy, Amar. "Biofouling in reverse osmosis processes". Thesis, Zaghy, Amar (2016) Biofouling in reverse osmosis processes. Honours thesis, Murdoch University, 2016. https://researchrepository.murdoch.edu.au/id/eprint/33970/.

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Reverse Osmosis (RO) is a water purification technology that uses a semi-permeable membrane to remove salt and other particles from drinking water. It is the dominant technology which has overtaken many conventional systems in recent years. Membrane biofouling is the main disadvantage of using RO technology which can result in reducing the system’s efficiency. The rejected microorganisms on the surface of the membrane form a fouling layer (biofouling) which leads to a decline in permeate flux, increase of hydraulic resistance, increase in operating pressure, and shortening of the membrane life. Polysaccharides, produced by microorganisms, are the main substances responsible for membrane biofouling. In this study, two types of polysaccharides (alginate and pullulan) were used to investigate their individual fouling effects as well as their fouling effects coupled with sodium chloride and calcium chloride. 50 mM of ionic strength (27.5 g NaCl + 1.47 g CaCl2) and 0.2 g/L of polysaccharides were used in the fouling experiments conducted with a laboratory-scale reverse osmosis system. It was found that alginate lead to more reduction in system’s efficiency in comparison with pullulan. The effect of alginate on the efficiency of the system was much more severe in the presence of salt, namely sodium chloride and calcium chloride, compared to its individual effect in the absence of salt. The addition of salt led to an increase in membrane fouling and a decrease in system’s efficiency. On the other hand, it was found that pullulan enhanced the system’s efficiency when it is combined with salt. To support the above findings, a Confocal Laser Scanning Microscopy (CLSM) analysis, a Total Organic Carbon (TOC) test, and an estimation of the weight of produced fouling layers were performed. In general, analysing the results of the tests supported the findings.

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Aguiar, Alessandra Mara Locatelli de. "Avaliação do processo de concentração osmotica para obtenção de banana passa". [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255529.

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Orientador: Roberto Herminio Moretti
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-06T15:51:38Z (GMT). No. of bitstreams: 1 Aguiar_AlessandraMaraLocatellide_M.pdf: 1450258 bytes, checksum: 8496d97a288559f534ce39db89383b61 (MD5) Previous issue date: 2006
Resumo: O Brasil é um país com característica agrícola e o desenvolvimento dos setores agroindustriais é de grande importância sócio-econômica e que devem ser explorados a fim de evitar o desperdício de alimentos, agregar valor aos produtos agrícolas e aumentar a renda dos produtores. A transformação industrial, à experiência de regiões e países bem sucedidos, mostra que pelo menos a transformação primária das frutas deve ser pensada pelos produtores. Isto porque é um prolongamento das atividades agrícolas, que objetiva transformar produtos perecíveis em produtos estáveis. A bananicultura é uma atividade de importância econômica e social, sendo cultivada na maioria dos países tropicais. O Brasil é o terceiro maior produtor e representa cerca de 9,0% da produção mundial, com uma área de 495 mil ha, superado apenas pela Índia e pelo Equador. O presente trabalho estudou o processo de concentração osmótica em banana nanica (Musa cavendishi) através de planejamento experimental completo com 3 variáveis independentes (tempo, espessura e concentração de ácido cítrico), utilizando soluções de açúcar invertido, à pressão atmosférica e temperatura constante de 45°C. As variáveis dependentes para os 17 experimentos realizados foram: perda de peso, perda de umidade, incorporação de sólidos, variação de sólidos totais, variação de sólidos solúveis e a relação brix / acidez (ratio) que indica o equilíbrio das características sensoriais do produto. Para identificar a melhor relação foram selecionados 4 experimentos com diferentes ratio. Estas amostras de banana préconcentradas osmoticamente foram secas em estufa com circulação forçada de ar quente a 60°C até atingirem um teor de 65% de sólidos totais. Foi realizada uma análise sensorial (teste de preferência) com as 4 amostras selecionadas. Os resultados obtidos com os experimentos mostram uma perda de umidade entre 25,13 a 38,16% no processo de concentração osmótica e um produto com boas características organolépticas
Abstract: Brazil is a country with agricultural characteristics and thus the development of the agro-industrial sector is of great socio-economic importance and should be explored so as to avoid food wastage and increase the value of agricultural products and producer profit. Based on the experience of highly successful regions and countries, in industrial transformation, the primary transformation of fruits should be thought of by the producers, since this is really a prolongation of the agricultural activity, with the aim of transforming perishable products into stable ones. The culture of bananas is an economically and socially important activity, bananas being cultivated in the majority of tropical countries. Brazil is the third biggest producer, behind India and Ecuador, representing 9% of world production and occupying an area of 495 thousand hectares. This work studied the osmotic concentration of banana nanica (Musa cavendishi) using a complete experimental design with 3 independent variables (time, thickness and citric acid concentration), using invert sugar solutions, atmospheric pressure and a constant temperature of 45ºC. The variable dependents for the 17 experiments carried out were: weight loss, moisture loss, solids incorporation, variation in total solids, variation in soluble solids and the brix:acidity ratio, which indicates the equilibrium of the product sensory characteristics. Four experiments with different ratios were selected in order to identify the best ratio. These osmotically pre-concentrated banana samples were dried in a forced air incubator at 60ºC to a total solids content of 65%. A sensory preference analysis was carried out with the 4 samples selected. The results obtained showed moisture losses from 25.13 to 38.16% in the osmotic concentration process and a product with good organoleptic characteristics
Mestrado
Mestre em Tecnologia de Alimentos

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11

Tshuma, Ivonne. "Brackish water treatment using pressure retarded osmosis (PRO) as a driving force for reverse osmosis (RO)". Thesis, Tshuma, Ivonne (2021) Brackish water treatment using pressure retarded osmosis (PRO) as a driving force for reverse osmosis (RO). PhD thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/61548/.

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The desalination process removes salts and contaminants from water to make it suitable for drinking and other beneficial purposes. Although Reverse Osmosis (RO) is currently the most energy-efficient, widely used desalination technology, it still requires a great deal of energy to create the high pressure necessary to desalinate seawater. The largest operating cost is the energy consumed in overcoming osmotic pressure and membrane resistance. Pressure Retarded Osmosis (PRO), on the other hand, utilises the salinity gradient between two solutions of different salt content to produce pressure, which can subsequently be used to generate electrical energy. This thesis describes how PRO can be used directly as the sole energy source for RO in an autonomous PRO-RO system without additional energy input without converting osmotic energy into electrical energy. The PRO-RO proof of concept was experimentally verified in a simple combined cell without cross-flow resulting in 12.5 bars of hydraulic pressure, and flux of 3.5 L m-2 hr-1 in the RO permeate. The PRO-RO system used PRO and RO brackish water feed solution and concentrated brine PRO draw solution (200 g/L NaCl). PRO is typically driven by freshwater to seawater gradient, but far greater energy can be predicted using hypersaline draw solutions. This study investigates the power density and maximum flux obtainable from two such saltwater solutions. The experimental data was verified by a transient model that predicts well (within 10%) PRO flux for all draw solution concentrations coupled with deionised water as feed. However, lower agreement with laboratory results was found for draw concentrations above 100 g/L when coupled with salty feed. Draw and feed cross-flow velocity were optimised at 0.1 m/s and 0.17 m/s, respectively. A cellulose tri-acetate forward osmosis membrane was used for experimental evaluation of power production by a PRO apparatus with pressure generation up to 40 bars. A numerical model was produced from the first principles and established theory on osmotic systems to aid understanding and project beyond the practical experimental results. The concept of combining the PRO driven by hypersaline and brackish water with a brackish water RO was investigated by modelling and simple proof of concept experiments. Theory suggests that the energy recovered from a PRO system keeps increasing with the draw solution's salt concentration. However, draw concentrations above 150 g/L did not result in a further increase in observed flux and observed energy (with a maximum pressure of 40 bars). Despite no gain in flux, modelled optimal power densities of 1.29, 12.19, and 62.4 W/m2 were obtained with increasing draw solution concentrations of 70, 150, and 300 g/L, respectively, with seawater feed solutions. A novel, autonomous pressure retarded osmosis (PRO) driven reverse osmosis (RO), with an energy recovery device (ERD), was proposed to replace RO high-pressure pumps. The experimental PRO power density outputs from seawater/brackish water feed with 300 g/L draw and RO power density requirements were analysed. Coupling PRO with RO at PRO maximum power densities was found not to be economically viable due to high pressures of 160 bars. The power density of 19.1 W/m2, achieved with brackish (10 g/L) feed and 300g/L draw, was sufficient to desalinate brackish water by RO at 30 bar pressure. Overall, brackish water feed and 300 g/L draw solution were used to model direct PRO to RO coupling efficacy. Using these feed and draw concentrations and the projected fluxes using currently available membranes, direct PRO to RO coupling of 2 m2 of PRO membrane to 1 m2 of RO membrane would produce 12.4 L m2 hr-1 of RO permeate at 30 bar applied pressure in an autonomous PRO-RO system.

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Corzo, García Beatriz. "Forward osmosis application for water reuse". Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/565820.

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Hybrid forward osmosis (FO) processes such as forward osmosis with membrane bioreactors (FO-MBR), electrodialysis (FO-ED), nanofiltration (FO-NF) or reverse osmosis (FO-RO) present promising technologies for wastewater reuse in agriculture. Their niche of application can be found when dealing with high-salinity wastewater in water stress situations, when the removal of trace organics or boron is targeted due to the multibarrier concept, or when water with high fouling potential is compulsory to treat, among other uses. In this case, one of these emerging technologies, FO-NF treatment has been studied at long-term with the aim of evaluating this technology at demonstration scale for irrigation purposes. In order to design the definitive pilot demonstration plant, an intensive evaluation of draw solutions (DS) was performed by focusing on the wastewater reuse applications of hybrid forward osmosis (FO) processes. The substances studied were potassium formate, potassium phosphate, magnesium sulphate, sodium chloride, sodium polyacrylate and polyethylene glycol, and their osmotic pressure, conductivity, pH, thermostability, sunlight exposure, toxicity, FO filtration performance and replenishment costs were determined. Based on these characteristics, three DS, sodium polyacrylate, magnesium sulphate and potassium phosphate, were selected as the most interesting to be evaluated in the demonstration plant. The results also revealed that the most relevant DS properties for wastewater reuse under the studied conditions were the DS regeneration method, DS replacement price, pH adjustment and toxicity. These properties were shown to be more relevant than filtration flux when a maximum DS osmotic pressure value of 10 bar was used, establishing this pressure as the limit for efficient DS recovery. Thus, prioritizing energy consumption, NF 270 4040 from Filmtec (Dow Chemical), were selected as the most suitable recovery nanofiltration (NF) membrane; because they offered the best relationship permeate flow/feed pressure with an adequate rejection. Additionally, to select the most suitable FO membrane, five commercially available FO membrane modules were evaluated and compared, where thin-film composite (TFC) flat sheet membranes from Porifera showed the highest flux and the highest salt rejection, and the lowest permeability and salt rejection values were presented by cellulose triacetate (CTA) hollow fibre membranes from Toyobo. Based on the information obtained, a FO/NF demonstration plant was constructed next to the wastewater treatment plant (WWTP) in San Pedro del Pinatar, in the region of Murcia (Spain). This plant represented the world’s first FO demonstration plant for municipal wastewater reclamation to be evaluated for agricultural purposes. The plant was operated treating 3 m3 h-1 of real wastewater with an average salinity of 3-5 mS cm-1 and 1.5 mg L-1 of boron in continuous mode for 480 days. Two of the three DS that had been previously selected (sodium polyacrylate and magnesium sulphate) were evaluated in different periods of experimentation. In a later study, magnesium chloride was catalogued as a DS with great potential to achieve economical expenses during the whole operation. The operation with sodium polyacrylate led to reversible fouling on the FO and NF membranes and the permeate was not suitable for irrigation. Although the permeate quality obtained was acceptable using magnesium sulphate as DS, this generated severe irreversible fouling on NF membranes and therefore, it was discarded. Finally, magnesium chloride showed the best performance, with FO-NF membranes presenting a stable permeability and low membrane fouling during long- term operation. The FO-NF permeate showed high quality for irrigation, achieving a conductivity value of 1 mS cm-1, a boron concentration below 0.4 mg L-1 and an average sodium adsorption ratio (SAR) of 1.98 (mequ L-1)0.5.
La ósmosis directa (OD) utiliza los principios de la ósmosis para desalinizar agua. El proceso de ósmosis directa utiliza un fluido denominado solución extractora a partir del cual se extrae agua de la fuente principal a través de una membrana semipermeable, aprovechando las diferencias de presión osmótica. Este proceso tiene la desventaja de que no genera agua de alta calidad en una sola etapa debido a que el agua producto se mezcla con el agente osmótico de la solución extractora. Así, se debe prever un sistema de separación del agente extractor para obtener el agua deseada, lo que se denomina sistema híbrido. Durante la tesis doctoral se estudió un sistema híbrido OD-Nanofiltración a escala piloto, demostrando que el proceso híbrido OD-NF es una tecnología con baja propensión al ensuciamiento, que puede lograr un permeado estable y de alta calidad para la reutilización de aguas residuales en una operación a largo plazo. Sin embargo, el consumo energético y del agente extractor es relevante. La falta de módulos de membrana de OD optimizados y disponibles en el mercado sigue siendo la principal limitación para la aplicación del proceso de OD a gran escala. En un futuro cercano, se espera que este proceso emergente se vuelva más sostenible y competitivo para el caso de uso estudiado en esta tesis.

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13

Maskan, Fazilet Chemical Engineering &amp Industrial Chemistry UNSW. "Optimization of reverse osmosis membrane networks". Awarded by:University of New South Wales. Chemical Engineering and Industrial Chemistry, 2000. http://handle.unsw.edu.au/1959.4/18790.

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The optimization of a reverse osmosis (RO) system includes optimization of the design of the individual membrane modules, the system structure and the operating conditions of the system. Most previous studies considered either the optimal design of individual modules only or optimization of system structure and operating conditions for fixed module dimensions. This thesis developed a method to simultaneously optimize the module dimensions, system structure and operating conditions. The method comprised rules for generating a general superstructure for an RO system given the number of modules along with rules for generating technically and mathematically feasible sub-structures. The superstructure was based on maximum connectivity between unit operations. A connectivity matrix was used to represent the superstructure. The matrix was useful for checking sub-structure's feasibility and deriving a model for the sub-structure's optimization, comprising the minimum number of variables and constraints which minimized computational time and increased accuracy. For optimization, a nonlinear objective function of the annualized profit of the RO system was formulated, consisting of the revenue obtained from permeate sales, capital costs of the unit operations and operating costs for the system. It was found that RO system optimization is a nonconvex optimization problem. The most effective optimization procedure involved a combination of evolutionary computation, which was good for locating the global optimum, and a gradient-based method, which was superior in finding the exact optimum. Small population size, adaptive mutation rate and steady state replacement were the most efficient parameter settings for the evolutionary computation. Optimal design of two-stage RO systems with and without energy recovery, bypass and recycle streams was studied. Dimensions of predicted optimal modules approached those of current commercial modules but with much shorter feed channels. The mathematical optimum also had higher operating pressures. The optimum system structure was a series arrangement with different module dimensions in each stage. A sensitivity analysis showed that trends in the optimal design were similar when unit costs changed. An investigation of the scalability of the method for a three-stage RO system revealed several weaknesses. These are probably surmountable with the addition of more RO system specific knowledge.

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Cohen, Ruben David. "Colloidal fouling of reverse osmosis membranes". Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15308.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1985.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.
Bibliography: leaves 128-133.
by Ruben David Cohen.
Ph.D.

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15

Al-Zuhairi, Ahmed. "A novel manipulated osmosis desalination process". Thesis, University of Surrey, 2008. http://epubs.surrey.ac.uk/2726/.

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The. present study, Manipulated Osmosis Desalination (MOD) looks at a process based on the replacement of the conventional reverse osmosis (RO) process, in which the water from a pressurised solution is separated from the solutes (the dissolved material) by a two stage membrane process. The fIrst stage uses forward osmosis (Fa) that naturally drives out the fresh solvent from a concentrated salt solution by manipulating the osmotic energy potential through innovative use of osmotic agents. The second step involves nanofiltration (NF) separation to regenerate the OA and produce the clean water. Optimising the fIrst step to achieve the highest quality and quantity ofwater is the focus of this research. Experiments were conducted on a flat bed bench scale rig. Quantitative results are displayed on the effect of draw solution solute concentration and feed salinity on the quality and quantity of produced water. Further data is displayed on the effect of varying the flow and temperature ofthe draw and feed solutions.

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16

Ding, Minxia. "Molecular simulations of reverse osmosis membranes". Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S058/document.

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L'osmose inverse (OI) est actuellement le procédé le plus utilisé mondialement pour le dessalement des eaux saumâtres et de l’eau de mer. Cette thèse s'est intéressée à la simulation moléculaire de membranes d'OI afin d'améliorer la compréhension des propriétés structurales, dynamiques et de transport de l'eau et d'ions à l'intérieur de ces matériaux. La membrane d'OI étudiée dans ce travail est une membrane de polyamide aromatique, matériau le plus utilisé actuellement en OI. Dans la première partie de ce travail, une méthodologie a été développée pour construire un modèle atomique en trois dimensions d'une membrane polyamide fortement réticulé. Des simulations de dynamique moléculaire à l’équilibre (EMD) et hors-équilibre (NEMD) ont été réalisées pour étudier le comportement de l'eau et des ions Na+ et Cl- à travers la membrane. Les simulations EMD ont montré que les caractéristiques structurales de la membrane modèle étaient en bon accord avec celles d'une membrane typique d'OI. Les propriétés dynamiques et diélectriques de l'eau confinée dans la membrane ont également été étudiées et il a été montré que celles-ci étaient fortement modifiées par rapport à une phase volumique. Deux types de techniques NEMD ont été utilisés pour étudier le transport baromembranaire à travers la membrane modèle. La perméabilité à l'eau pure a été trouvée en très bon accord avec les données expérimentales rapportées dans la littérature et les deux méthodes NEMD ont révélé une très forte rétention saline, confirmant ainsi la pertinence du modèle de membrane d'OI développé dans ce travail
Reverse osmosis (RO) is currently the leading process used worldwide for both brackish and seawater desalination. This thesis focuses on the molecular simulation of RO membranes in order to improve the understanding of structure, dynamics and transport of water and ions inside these materials. The RO membrane studied in this work is a typical polyamide RO membrane. In the first step of this work, a methodology for building a fully atomic and three-dimensional model of a highly cross-linked polyamide membrane was developed. Both equilibrium molecular dynamics (EMD) and non-equilibrium molecular dynamics (NEMD) simulations were further performed to investigate the behavior of water and ions (Na+ and Cl-) through the membrane. EMD simulations showed that the structural characteristics of the model polyamide membrane were in good agreement with those of a typical RO membrane. The dynamics and dielectric properties of water confined in the RO membrane were also studied and have shown to be dramatically modified with respect to the bulk phase. Two types of NEMD techniques were employed to investigate pressure-driven transport through the model membrane. Pure water permeability was found to be in very good agreement with experimental data reported in the literature for similar membrane materials and both NEMD methods highlighted very high salt rejection properties, thus confirming the relevance of the model membrane developed in this work

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17

Al-Jeshi, Subhi. "The effect of reverse osmosis membrane microscopic structure on its performance and reverse osmosis performance in oily water". Thesis, Heriot-Watt University, 2004. http://hdl.handle.net/10399/348.

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18

Nurlaila, Gita G. "Development of reverse osmosis low-pressure membranes". Thesis, University of Ottawa (Canada), 1997. http://hdl.handle.net/10393/4342.

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Thin film composite (TFC) membranes were developed for reverse osmosis (RO) under low pressure. Three commercial membranes, i.e. one type of polyvinylidene fluoride, namely AP-10, and two types of polyethersulfone, namely HW-18 and E-500, were used as substrate membranes. Sulfonated poly(2,6-dimethyl-1,4-phenyleneoxide), known as SPPO, was used as the ultrathin barrier layer of the composite membranes. The performances of the three substrate membranes were compared. The pore size and the pore size distribution of the substrate membranes were studied. Then the RO performances of the substrate membranes coated with SPPO were compared. It was observed that a high electrolyte separation without scarification of permeate flux was attained when membrane E-500 was used as the substrate membrane. Afterwards, the effects of the number of coating layers and the coating solution concentrations on RO performance of the TFC membranes, using E-500 membrane as the substrate membrane, were studied. The optimum coating solution concentration and the number of coating layers for maximum electrolyte separation were determined. The TFC membrane was then subjected to post-treatments, i.e. annealing and heat treatment under water, to improve the permeate flux. The final post-treated TFC membrane performance was concluded to be close to the targeted value.

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19

Levitan, Jeremy Asher 1977. "Experimental investigation of induced-charge electro-osmosis". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34558.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
Includes bibliographical references (leaves 103-107).
We analyze the general phenomenon of induced-charge electro-osmosis (ICEO), nonlinear electro-osmotic slip generated when an electric field acts on its own induced charge around a polarizable surface, in the context of microfluidics. Simple ICEO flows are first observed around a platinum wire in a polymer microchannel. While convenient for scaling analysis of resulting flows, this geometry proved difficult to analyze because of sensitivity to measurement height. This motivated the development of microfabrication techniques for the creation of electroplated metal structures with clean surfaces for ICEO flow characterization. ICEO flows are analyzed in a simple geometry, with an electroplated metal cylinder and two outer electrodes on a glass substrate. ICEO flow velocities scale as V2, where V is the potential drop across the outer electrodes, and decay monotonically with increasing frequency. Flow velocity also decays with increasing electrolyte concentration. Fixed-potential ICEO, with non-zero fixed charge on the polarizable surface, is demonstrated around a metal cylinder. A range of electrolyte solutions are tested in ICEO flow geometries and measured velocities scale well with effective salt diffusivity. Finally, we propose ICEO microfluidic systems as solid-state pumps and mixers for a variety of possible applications.
(cont.) A range of electrolyte solutions are tested in ICEO flow geometries and measured velocities scale well with effective salt diffusivity. Finally, we propose ICEO microfluidic systems as solid-state pumps and mixers for a variety of possible applications.
by Jeremy Asher Levitan.
Ph.D.

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20

Alves, Filipa Cristina Conceição. "Development of polymeric membranes for forward osmosis". Master's thesis, Faculdade de Ciências e Tecnologia, 2010. http://hdl.handle.net/10362/4798.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Química e Bioquímica
Forward osmosis (FO) using a semi-permeable membrane may be a viable alternative to reverse osmosis (RO) as a lower cost and more environmentally friendly desalination technology. To develop a FO membrane showing high water flux and high salt rejection, P84 Lenzing polyimide flat sheet membranes were fabricated by immersion precipitation from a casting solution containing dimethylformamide (DMF) as the solvent and 1,4-Dioxane (dioxane) as the co-solvent.. Different P84 concentrations as well as different solvent systems compositions were tried. The composition of the solvent system showed to provide control over the molecular weight cut-off and porosity of the resultant membranes. High water flux (2.18 kg.m-2.h-1) and improved salt rejection (95.2%) in FO were achieved by using 18 wt.% P84, DMF:Dioxane, 1:6, crosslinked for 4h by 1,6-Hexanediamine (HDA). Glycerol and Polyethylene glycol (MW 400 g.mol-1) (PEG) were used to store membranes after casting in order to prevent pores collapse. The best membrane fabricated, 18 wt.% P84, DMF:Dioxane, 1:6, showed better performance when stored in PEG than when stored in glycerol. Internal concentration polarisation is thought to be the cause for the experimental FO water fluxes, which were far lower than those theoretically predicted based on bulk osmotic pressure difference and membrane pure water permeability data.

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21

Monteiro, Maria Inês Gonçalves. "Forward osmosis membranes tailored by hydrogel coatings". Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/9833.

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Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica
Forward osmosis (FO) is a promising process to substitute reverse osmosis (RO), as a lower cost and more environmentally friendly desalination process. However, FO still presents some drawbacks, in particular the several internal concentration polarization (CP) effects and insufficient salt selectivity. In order to overcome these disadvantages, this study focuses on the use of hydrogel surface-coated FO membranes to minimize internal CP effect in water purification, and also to improve membrane salt rejection. For this, a series of crosslinked poly(ethylene glycol) (PEG)-based hydrogels were synthesized, by the photopolymerization of poly(ethylene glycol) diacrylate (PEGDA) and the monomer (PEG) in the presence of a photoinitiator. The water uptake and salt permeability of the resulting films were controlled by manipulating the composition ratio of PEGDA and the monomer PEG, by varying the water content in the prepolymerization mixture and the UV-exposure time. High water uptake and low salt permeability values were observed for the films prepared with 50wt% of water content(50%PEGDA). The hydrogels were applied using different techniques (pressure, soaking and coating) to a cellulose acetate (CA) membrane prepared by phase inversion. However, only one technique was effective, surface coating. The CA membranes coated with these hydrogels materials showed an improvement in NaCl rejection (≅100%) and in some cases an enhancement of 100 and 120% of the original water flux (50% PEGDA coating on the active layer and on the porous support, respectively; in PRO mode). The 50%PEGDA coated membrane (with a coating on the porous support) has also shown reduction of the internal CP effects.

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22

Mazlan, Nur Muna. "Forward osmosis for desalination and water recovery". Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/45550.

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In recent years, there has been an increased interest in forward osmosis (FO) from academic research and industry with a rising number of FO academic publications in the last decade. The common perception of FO as a low energy process compared to reverse osmosis (RO) sparked interest in this area. Nevertheless, there are some major challenges that need to be addressed before FO can be successfully implemented as an effective technology. Some of these challenges are addressed in this dissertation, starting with the assessment of FO as a low energy process. A modelling approach was used to assess the energy consumption of various FO hybrid processes and provide a detailed comparison with RO for desalination, in an effort to answer the critical question: Is FO truly a low energy process compared to RO? Results showed that there was practically no difference in specific energy consumption (SEC) between standalone RO, and FO with nanofiltration (NF) draw solution (DS) recovery; this can be generalised for any pressure-driven membrane process used for the DS recovery stage in a hybrid FO process, such as UF or RO. It was also found that even if any or all of the membranes considered, FO, RO or NF, were perfect (i.e. had infinite permeance and 100% rejection), it would not improve the SEC significantly. Furthermore, in order to reduce the higher membrane footprint required by FO hybrid processes, internal concentration polarisation (ICP) within the support has to be greatly reduced or eliminated. Hence, any advantage possessed by the FO hybrid process derives from the lower fouling propensity of FO, lower pretreatment costs arising from reduced fouling, use of draw solutes which can be recovered with low cost thermal energy sources and specific applications where RO cannot compete. Inspired by this insight, subsequent work was performed to study the multifaceted interactions alongside membrane and process parameters involved in the fouling of FO membranes, specifically the HTI TFC and CTA membrane. The chapter on organic fouling behaviour of structurally and chemically different FO membranes revealed that fouling on the HTI TFC membrane was more significant compared to HTI CTA in both membrane orientations, arising from a variety of factors associated with surface chemistry, membrane morphology and structural properties. Interestingly, it was observed that in FO mode, membrane surface properties dominated over fouling layer properties in determining fouling behaviour, with some surface properties (e.g. surface roughness) having a greater effect on fouling than others (e.g. surface hydrophilicity). In PRO mode, structural properties of the support played a more dominant role whereby fouling mechanism was specific to the foulant size and aggregation as well as the support pore size relative to the foulant. Whilst pore clogging was observed in the TFC membrane due to its highly asymmetric and porous support structure, fouling occurred as a surface phenomenon on the CTA membrane support layer, indicating that the latter’s structure was more symmetric in relation to the foulant (alginate) studied. Besides pore clogging, the severe fouling observed on the TFC membrane in PRO mode was due to a high specific mass of foulant adsorbed in its porous support. A new method was successfully introduced to quantify the density of the fouling layer and correlate it with hydrodynamic conditions and fouling behaviour of the membranes studied. It was observed that a trade-off between enhanced membrane performance and fouling mitigation is apparent in these membranes, with both membranes providing improvement in one aspect at the expense of the other. Hence, significant development in their surface and structural properties are needed to achieve good anti-fouling properties without compromising flux performance. Measured fouling densities on the studied surfaces suggest that there is not a strong correlation between foulant-membrane interaction and fouling density. Cleaning results suggest that physical cleaning was more efficient on the CTA membrane compared to the TFC membrane. Further, they implied that despite different mechanisms of fouling and quantities of foulant adsorbed in FO membranes, FO is a resilient process with high cleaning efficiencies and fouling reversibility. Finally, to address the challenge of ICP, a novel method of fabricating FO membranes was developed by interfacially polymerising a free-standing, salt rejecting polyamide (PA) film using a floating technique and directly depositing this layer onto an open mesh fabric. By doing this, the need for a phase inversion support was entirely eliminated. The fabrication method resulted in the successful formation of a defect-free, salt-rejecting FO membrane with significantly reduced or eliminated ICP, attributed to large open mesh sizes and straight channels in the fabric support. Interestingly, it was observed that even in the absence of ICP, flux was limited by the support layer at lower effective open areas of the mesh fabric. At higher mesh sizes and effective open areas, the effect of the fabric support became less significant and FO performance was likely governed by diffusion through the PA film, limited by its structure and transport properties. A trade-off between surface roughness and thickness of the PA film was observed, which is linked to the mechanism of film formation at the bulk interface. It was proposed that the design of FO membranes with ideal supports should also include tailoring the PA film properties in order to achieve superior FO performance. Additionally, the use of supports with higher percentage open areas or porosities should be considered.

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23

Hoffman, Anton Michael. "Design guidelines for a reverse osmosis desalination plant / Anton Michael Hoffman". Thesis, North-West University, 2008. http://hdl.handle.net/10394/4211.

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There are two basic needs globally and that is the control and supply of reliable electricity and clean water. However, one of the biggest challenges the world is facing today is the lack of fresh water resources. Lower rainfall, together with population and industry growth, are only a few factors contributing to the fast increasing strain on existing water supplies around the world. This fast increasing need therefore necessitates the investigation into finding alternative sources. One such option is that of desalination. In the last 50 years desalination technologies have been applied to produce high quality fresh water from brackish and seawater resources. In the 1980's a breakthrough was made with the introduction of the membrane desalination technology, known as the reverse osmosis (RO) process. Today newly developed technologies are improving the competitiveness of the reverse osmosis process against the traditional distillation processes. There are a number of options to increase the efficiency of a reverse osmosis plant and one option is to use warm industrial waste water as the feed water to the desalination plant. It is known that the viscosity of water is inversely proportional to its temperature. Therefore, if the feed water temperature of a reverse osmosis plant is increased the membranes will become more permeable. This will result in a higher production volume or in a lower energy demand. South Africa is on the edge of building the first fourth generation nuclear power plant, called the Pebble Bed Modular Reactor (PBMR) at Koeberg. The PBMR will produce a cooling water outlet temperature of 40°C which can be used as feed water to a reverse osmosis plant. In this study design guidelines of a reverse osmosis plant are given in nine steps. These steps were then used during a basic component design of a reverse osmosis plant coupled to the waste water stream of a PBMR nuclear power plant. Furthermore design software programs were used to simulate the coupling scheme in order to validate the outcome of the design guidelines. The results of the two design approaches compared well to one another. It furthermore showed that by using the waste water from the PBMR nuclear power plant the efficiency of the RO plant is increased and the operating cost is decreased. Fresh water can be produced at a cost of R 5.64/m3 with a specific electricity consumption of 2.53 kWh/m3.
Thesis (M.Ing. (Nuclear Engineering)--North-West University, Potchefstroom Campus, 2009.

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24

Alves, Denise Gomes. "Obtenção de acerola (Malpighia punicifolia L.) em passa utilizando processos combinados de desidratação osmotica e secagem". [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256336.

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Orientador: Fernanda Elizabeth Xidieh Murr
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-03T18:27:51Z (GMT). No. of bitstreams: 1 Alves_DeniseGomes_D.pdf: 7580530 bytes, checksum: db12199d14d28ee9a851ac02dd6b4351 (MD5) Previous issue date: 2003
Resumo: O presente trabalho teve a finalidade de obter acerola em passa utilizando processos combinados de desidratação osmótica e secagem. Foi estudada a influência da desidratação osmótica utilizando soluções binária (água+sacarose) e ternária (água+sacarose+sal) na secagem convectiva de acerola (Malpighia punicifolia L.). Para os pré-tratamentos foram avaliadas as influências do tempo (30 e 90 minutos), temperatura (25 e 60°C) e concentração de sacarose (30 e 60 % p/p) para a solução binária e concentração de sacarose (20 e 50% p/p) para a solução ternária (10% de sal), nas respostas perda de peso, perda de água, ganho de sólidos e na relação ganho de sólidos/perda de água. Para cada solução foi escolhida uma condição para proceder à secagem convectiva e essa condição foi determinada pelo menor valor da relação ganho de sólidos/perda de água. As condições escolhidas foram: solução binária com 60% de sacarose e solução ternária com 50% de sacarose e 10% de sal, ambas na mesma temperatura de 60°C e mesmo tempo de imersão (90 minutos). Foram avaliadas as influências da temperatura (43, 50, 60, 70 e 77°C) e velocidade do ar de secagem (0,50; 0,65; 1,00; 1,35 e 1,50 m/s) nas respostas atividade de água (aw), perda de vitamina C (PC) e tempo de secagem (ts). A acerola desidratada osmoticamente com solução ternária apresentou menores valores de aw, PC e ts. A acerola congelada apresentou os maiores valores de aw, PC e ts, enquanto que a desidratada osmoticamente com solução binária apresentou valores intermediários entre as outras duas condições. Para a análise sensorial foram escolhidos amostras com menores valores de aw, PC e ts. A acerola congelada não foi avaliada sensorialmente por apresentar valores de aw muito elevados, próximos aos valores apresentados pela fruta in natura. A acerola desidratada osmoticamente com solução binária foi a mais aceita pelos provadores situando-se entre as categorias "gostei ligeiramente" e "gostei moderadamente"
Abstract: In the present work it was studied the influence of the osmotic dehydration process using binary (sucrose+water) and ternary (sucrose+salt+water) solutions in the convective drying of acerola fruit (Malpíghía punícífolía L.). Pretreatments were evaluated by influences of immersion time (30 and 90 minutes), temperature (25 and 60°C) and sucrose concentration (30 and 60% w/w) for binary solution and sucrose concentration (20 and 50% w/w) for the ternary solution (10% of salt), on responses of weight loss, water loss, solid gain and solid gain/water loss ratio. For each solution, a condition was stablished to proceed to the convective drying and that condition was determined by the smallest value of the solid gain/water loss ratio. The chosen conditions were: binary solution with 60% of sucrose and ternary solution with 50% of sucrose and 10% of salt, both in the same temperature of 60°C and same immersion time (90 minutes. Influences of temperature (43, 50,60, 70 and 77OC) and air velocities (0,50; 0,65; 1,00; 1,35 and 1,50 m/s) on responses water activity (aw), vitamin C loss (PC) and drying time (ts). Osmotically dehydrated acerola fruit with ternary solution presented smaller values of aw, PC and ts. Frozen acerola fruit presented the largest values of aw, PC and ts, while osmotically dehydrated acerola fruit with binary solution presented intermediate values as compared to other conditions. For sensorial analysis they were chosen samples with smaller values of aw, PC and ts. The frozen acerola fruit was not evaluated in sensorial analysis because presented very high values of aw, close to the values presented by fresh fruit. Osmotically dehydrated acerola fruit with binary solution was more acceptable, with acceptance values in the categories "Iiked lightly" and "liked moderately."
Doutorado
Engenharia de Alimentos
Doutor em Engenharia de Alimentos

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25

Fang, Yi. "Fractionation of organic liquid mixtures by reverse osmosis". Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5890.

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A systematic investigation has been conducted to demonstrate the general applicability of reverse osmosis (RO) fractionation of organic liquid mixtures by laboratory prepared cellulose acetate butyrate (CAB) and aromatic polyamide (PA) membranes. Surface excess values have been determined by liquid chromatography (LC) technique for the four model organic liquid mixtures for CAB and PA materials. The principal findings of this study are: (i) separations take place in all the four model organic liquid mixtures, and PA membranes given separations higher than CAB membranes under same experimental conditions; (ii) preferential sorption exists in all the four model systems for CAB and PA materials, (iii) the RO results are explained by the combined consideration of surface excess data determined from LC, and Stokes' Law radius calculated from literature data.

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26

Holloway, Ryan W. "Forward osmosis for concentration of anaerobic digester centrate". abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1436020.

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27

Bouma, Andrew Thomas. "Split-feed counterflow reverse osmosis for brine concentration". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118668.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 73-77).
Brine concentration is a useful operation that allows for increased recovery ratios in water treatment systems, reduction of waste volumes, and the production of minerals from saline brines. As our world moves towards a more sustainable future, improvements in energy-efficient brine concentration will be important. While viable brine concentration technologies exist, current methods are often inefficient. In this thesis, a model is developed to simulate Counterflow Reverse Osmosis (CFRO), a membrane-based, pressure-driven brine concentration technology. Using this model, a single CFRO module is simulated and its performance characterized. Entropy generation within a single-stage system is analyzed, which provides insights for configuring and optimizing multistaged systems. Additionally, a parametric analysis of membrane parameters provides direction for the development of CFRO-specific membranes. Two existing configurations of CFRO are discussed, and compared with a new third configuration, split feed CFRO, which is presented for the first time here. Split feed CFRO systems are simulated and optimized to provide guidance for system design. A variety of multistage systems operating at a range of recovery ratios are simulated, and the results compared are with existing desalination and brine concentration technologies. Potential is shown for the maximum recovery ratio of RO systems to increase significantly when hybridized with split-feed CFRO brine concentration systems, while the energy requirements of these hybridized systems is similar to, or an improvement on, the expected performance of conventional RO systems operating at high pressures and the same conditions. A large reduction in energy usage when compared to commonly used evaporative brine concentrators is shown to be possible.
Funded by the Kuwait Foundation for the Advancement of Sciences (KFAS) Project No. P31475EC01
by Andrew Thomas Bouma.
S.M.

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28

Kovacs, Jason Richard. "Engineering nanostructured selective layers for reverse osmosis membranes". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98709.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 122-142).
A major challenge to communities across the world in the next century will be ensuring millions have access to adequate freshwater resources. Studies from the UN World Health Organization indicate that over 1.1 billion people currently lack access to reliable and secure freshwater supplies, with an estimated 2.5 million deaths per year from diseases associated with poor access and sanitation in 2007. Reverse osmosis (RO), a process through which water is desalted via pressurized flow past a salt-selective membrane, is an energy-efficient method to generate freshwater from oceanic, brackish, and waste water sources. However, there are a number of challenges to scaling up RO processes to large scale production, including the need to improve membrane selectivity and throughput. One method to assemble selective layers for RO membranes is layer-by-layer (LbL) assembly, which is a flexible, scalable assembly technique that enables the incorporation of a myriad of polyelectrolytes and inorganic nanoparticles into thin films. There is a gap in the scientific literature concerning the use of LbL to generate RO selective layers where previous approaches have not taken full advantage of the LbL process to incorporate nanomaterials that can generate ordered nanostructures for salt rejection. In particular, high-aspect ratio clay platelets are ideal for such a purpose; it was hypothesized that effective salt rejection could be achieved by hindering the diffusion of solvated ions through nano-channels formed by the platelets embedded within a polymer matrix. This body of work examines the application of spray layer-by-layer (spray-LbL) assembly with clay composite thin film architectures to generate nanostructured selective layers for use in RO membrane technology. First, appropriate substrates were identified as support layers for the deposition of spray- LbL assembled clay composite thin films. Both electrospun bisphenol-A polysulfone (PSU) mats of varying fiber diameter and polyethersulfone (PES) ultrafiltration (UF) membranes with varying pore diameters were examined. Second, a range of materials were investigated for the spray-LbL deposition of clay composite films. Laponite clay platelets were incorporated into several different film architectures including strong polyelectrolytes as well as cross-linkable weak polyelectrolytes to form both bilayer and tetralayer film architectures. The clay content was controlled via manipulating assembly conditions such as the pH and spray times of the film components. Assembled membrane architectures were tested at industrial RO operating conditions in dead-end permeation cells and evaluated for salt rejection, water permeability, and mechanical strength. Ultimately, it was determined the most uniform and robust films were those deposited on PES membranes with 30 nm pores, closely matching the characteristic length of the LAP clay platelets to reduce the impact of bridging. Although all the film architectures tested exhibited significantly greater water permeability than commercially available RO selective layers, the salt selectivity was found to be highly dependent on the film architecture and assembly conditions. The best performing film architecture consisted of a cross-linked clay composite tetralayer film, exhibiting salt rejection of 89% for aqueous 10,000 ppm NaCl solution with an order of magnitude increase in water permeability over a commercially-available thin film composite membrane. The key conclusion drawn from the studies indicate the presence of an optimal zone where the incorporation of clay platelets introduces additional salt selectivity via size exclusion, balanced with the cross-linked polymer component of the film to improve the mechanical strength and reduce the risk of critical defect formation during operation. Taken together, these investigations represent a new approach using structured nanomaterials to develop next generation clay composite RO selective layers. The increased water permeability of the clay composite selective layers offers an attractive advantage in desalting applications where high flux is desirable, such as with brackish water resources as well as in membrane unit operations near their thermodynamic limit.
by Jason Richard Kovacs.
Ph. D.

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29

Vásquez, Teneb Felipe. "Emro. Sistema purificador de agua por osmosis reversa". Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/138388.

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Memoria para optar al título de Diseñador Industrial
El presente escrito contiene la memoria del proyecto realizado para optar al título de Diseñador Industrial de la Universidad de Chile. El proyecto en sí consta del diseño de un sistema de purificación de agua ultrapura 1+, a partir del proceso de osmosis reversa. La propuesta del purificador de agua, se lleva a cabo a través de un equipo interdisciplinar formado por expertos en la Ingeniería Química, especialista en equipos de osmosis reversa; Ingeniería Eléctrica, especialista en microprocesadores y el Diseño Industrial. La finalidad del sistema es ser integrado a los laboratorios de investigación científica del país, aportando en disminuir el proceso de obtención del agua ultrapura, poniendo a su disposición un sistema que desarrolle este insumo dentro del laboratorio, para así optimizar el trabajo de investigación realizado, en términos de tiempo, gastos monetarios y operacionales, y calidad de resultados.

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Amjad, Muhammad. "Direct solar absorption nanofluids for forward osmosis desalination". Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/20706/.

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Solar energy is the most abundant and easily accessible source of renewable energy, however, its efficient use is not an easy task. Absorption of solar energy directly by the working fluid is an emerging trend in solar collection, known as direct solar absorption. On the other hand, almost one-third of the world population is living in water stressed conditions and this figure is expected to continuously increase in next a few decades. Desalination of sea and brackish water and reclamation of wastewater is being progressively practiced worldwide through different techniques. Forward osmosis (FO) is an emerging desalination technology, which operates under an internal osmotic gradient across the FO membrane. The lack of proper draw solutions with high osmotic pressure, minimum reverse solute flux and easy regeneration properties, however, limits the FO’s development. This work develops a novel concept of combining solar energy, nanoparticles and FO to produce potable water suitable in arid areas, far away from the grids. Two independent functions i.e. osmotic pressure and direct solar absorption, are integrated for the first time into purposely formulated nanofluids for FO solar desalination. The direct solar absorptive nanofluid based novel draw solutions (NDS) are aimed at developing high osmotic pressure for enhanced water flux across FO membrane and, at the same time, to absorb solar energy efficiently for their regeneration. A number of nanofluids were formulated and characterized in terms of their morphologies, structures and elemental compositions. The characterized nanofluids were investigated experimentally for their direct solar absorption behaviour and FO performance. A unique hybrid of direct absorptive nanofluid and osmotically active matters was developed that sufficiently performed the proposed two functions in FO solar desalination. The photothermal conversion performance of engineered NDS was examined under a solar simulator and the results revealed the influence of nanoparticle type and concentration. The inclusion of low concentrations of nanoparticles could improve solar capture significantly. In direct solar absorption and steam generation experiments, nine nanofluids were examined and an enhancement in bulk photothermal efficiency (PTE) of about 95%, 100% and 105% over the base fluid was observed with gold, silver and carbon nanofiber (CNF) nanofluids respectively. The most absorptive carbon nanofiber based nanofluid was surface functionalized for osmotic pressure enhancement and experimented as NDS for FO performance in terms of osmotic pressure, water flux, reverse solute flux and water recovery. The NDS developed sufficient osmotic pressure and an enhancement of 80% in water flux was observed over 1M salt solution used as reference. The reverse solute flux of the NDS was negligible and the quality of product water was within the potable water standards. The experimental results showed that the proposed novel draw solutions can sufficiently develop osmotic pressure to permeate water across the FO membrane and in the same time, significantly enhance the potable water generation using solar energy. Moreover, the quality of produced water suggested that these novel draw solutions could be potential candidates for future FO desalination in arid areas by using the energy from the Sun.

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31

Detrich, Kahlil. "Electroding Methods for in situ Reverse Osmosis Sensors". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31207.

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The purpose of this work is to develop and evaluate electroding methods for a reverse osmosis (RO) membrane that results in an in situ sensor able to detect RO membrane protein fouling. Four electroding techniques were explored: i) gold exchange-reduction, ii) encapsulated carbon grease, iii) â direct assembly processâ (DAP), and iv) platinized polymer graft. The novel platinized polymer graft method involves chemically modifying the RO membrane surface to facilitate platinization based on the hypothesis that deposition of foulant on the platinized surface will affect platinum/foulant/solution interfacial regions, thus sensor impedance. Platinized polymer graft sensors were shown to be sensitive to protein fouling. Electrodes were characterized by their electrical properties, SEM and XPS. Assembled sensors were evaluated for sensitivity to electrolyte concentration and protein fouling. Micrographs showed coating layers and pre-soak solution influence gold exchange-reduction electrode formation. High surface resistance makes gold exchange-reduction an unsuitable method. Concentration sensitivity experiments showed carbon grease and DAP electroding methods produce unusable sensors. Carbon grease sensors have time-dependent impedance response due to electrolyte diffusion within the micro-porous polysulfone support. DAP electroded sensors proved quite fragile upon hydration; their impedance response is transient and lacks predictable trends with changes in concentration. A parametric study of the platinized polymer graft method shows amount of grafted monomer correlates to grafting time, and deposited platinum is a function of exchange-reduction repetitions and amount of grafted monomer. Platinized polymer graft sensors were fouled in both dead-end and cross-flow RO systems, and their impedance trends, while varying between sensors, indicate protein-fouling sensitivity.
Master of Science

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32

Digman, Brett R. "Surface Modification of Polybenzimidizole Membranes for Forward Osmosis". University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1270832021.

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33

Al, Shaalan Hakem. "Artifical neural network modelling of reverse osmosis process". Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9516.

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With the increase in population and the scarcity of fresh water in the Middle East desalination has taken an important role in the provision of water for everyday use and for industrial purposes. Reverse osmosis water treatment process is of particular interest as it is one of the key processes in a desalination plant. The modelling of this process and the prediction of permeate flow is useful in better understanding the process. In the present study, an artificial neural network based model was developed based on plant data for the prediction of permeate flow performance. Plant data was collected and a number of variables determined. Principal component analysis was then carried and factor loadings obtained to identify the main variables. Once the main input variables were obtained a statistical analysis of the data was done in order to remove outliers present in the data. This was done because the presence of outliers in data to be analysed using ANN models renders the models ineffective in prediction of an output. Once the removal of outliers was done, the data was then analysed using the developed model. 1081 sets of data were originally used with twelve input variables. After principal component analysis was done the input variables were reduced to five with one output variable. With the removal of outliers 981 sets of data were obtained and these were then used in the model. The model was able to predict the output accurately with r2 at 0.97. Key factors determined from the process were that to obtain an optimum network one has to consider the epoch size, the transfer function, the learning rate and finally the number of nodes in the hidden layers. The number of hidden layers also had an effect on the overall prediction of the data. It is also important when using ANN models to obtain the correct input variables and to remove any outliers that are present in the data in order to be able to predict the output. The use of plant data severely limited optimisation of the process due to it already being heavily optimised.

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34

Harrison, Don. "Solar powered reverse osmosis desalination for remote communities". Thesis, Harrison, Don (1989) Solar powered reverse osmosis desalination for remote communities. Honours thesis, Murdoch University, 1989. https://researchrepository.murdoch.edu.au/id/eprint/40085/.

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Many Aboriginal Outstations in Western Australia have bores which produce drinking water of such a low standard that the health of the community members is at risk. Major concerns are the high concentrations of sale, nitrates and fluoride and bacteriological contamination. Communities faced with this problem have four choices. They can sink another bore nearby in the hope of finding better water, which would be expensive and not necessarily successful. They can physically move to another location which would be socially and culturally disruptive. They can accept the risk and drink the water untreated. Recent innovations in reserve osmosis desalination now make it possible to treat the water on site using solar power. The appropriateness of this new technology for remote locations is analysed. A means of predicting the power requirements of a unit capable of supplying the drinking water needs of a small community, estimated at up to 1 m3 per day is derived. A small commercially available unit was tested and it was found that in summer it could produce a steady flow of over 5 L/hour for 10 hours per day when used with a solar tracker and a power optimiser. Two designs were developed which could supply the desired 1 m3 flow rate from the power of two 55 W solar panels. A prototype of one design has been constructed and early testing demonstrate that is is capable of producing up to 400 L/day even at low pump efficiencies. Minor improvements are likely to substantially improve production in the near future.

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35

Susanto-Lee, Robertus. "Efficiency improvements for small-scale reverse-osmosis systems". Thesis, Curtin University, 2006. http://hdl.handle.net/20.500.11937/286.

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The water supplies of some small inland communities may come in the form of river systems that offer brackish water. Not fit for immediate human consumption, the water can be further processed using reverse osmosis to be converted into drinking water.In very remote areas there are limited energy resources, and for those areas that lie beyond a municipal distribution grid, renewable energy sources may be used. A reverse osmosis system that operates from the limited power generated by a renewable energy system must do so with the utmost of efficiency. Three methods in improving the efficiency of small-scale reverse-osmosis system are investigated, namely high-pressure pump speed control, feed water heating and vacuum pump based energy recovery.

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36

Susanto-Lee, Robertus. "Efficiency improvements for small-scale reverse-osmosis systems". Curtin University of Technology, Department of Electrical Engineering, 2006. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=16974.

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The water supplies of some small inland communities may come in the form of river systems that offer brackish water. Not fit for immediate human consumption, the water can be further processed using reverse osmosis to be converted into drinking water.In very remote areas there are limited energy resources, and for those areas that lie beyond a municipal distribution grid, renewable energy sources may be used. A reverse osmosis system that operates from the limited power generated by a renewable energy system must do so with the utmost of efficiency. Three methods in improving the efficiency of small-scale reverse-osmosis system are investigated, namely high-pressure pump speed control, feed water heating and vacuum pump based energy recovery.

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37

Jiang, Zhirong y 蔣志戎. "Cataract induced by osmotic stress". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31241876.

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Jiang, Zhirong. "Cataract induced by osmotic stress /". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23339603.

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Dávila, Valle Melissa Paola, Medina Eduardo Francisco Rondon, Tillit Daniela Paola Navarro, Purizaga Mario Andre Cachay y Ovalle Luis Alberto Chura. "Aquamati". Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/626531.

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En este proyecto se desarrolla un nuevo producto que se lanzará al mercado de aguas Premium. En este abstracto se podrá observar el procedimiento que se desarrolló para poder analizar correctamente si el proyecto es rentable o no. Nuestro proyecto tiene como finalidad introducir al mercado un producto innovador, el cual es Aquamati; un agua ozonizada, la cual tiene diferentes beneficios con respecto a las aguas que comúnmente encontramos en el mercado. Este es un producto eco amigable, debido a que su presentación es en botella de vidrio reutilizable, y beneficioso para la salud, ya que el ozono es un purificador natural. En este trabajo podrán observar todas las etapas en las que desarrollamos ideas, entrevistamos a posibles consumidores, establecimos hipótesis de mercado, hicimos focus group en el que se evaluó el sabor y la imagen del producto y finalmente establecimos estrategias para poder insertar nuestro producto y hacerlo competitivo. Nuestra agua va dirigida a personas de nivel socioeconómico A y B entre 18 a 50 años que viven en Lima, con tendencia de compra de productos que incentiven la vida saludable y un perfil sofisticado. Finalmente, en el trabajo se visualiza toda de planeamiento de actividades como las de Recursos Humanos, Marketing, Responsabilidad Social, la parte del financiamiento y la parte contable de nuestro proyecto en el cual se ve la viabilidad del negocio.
This project entails the development of a new product that will be launched to the bottled water market. In this abstract, We'll show the process developed to correctly analyze if the project was profitable or not. Our project's goal is to introduce to the market a novel product, Aquamati is ozonized water, which has several benefits that regular bottled water in the market do not, It's an eco-friendly product, being possible to reuse its glass bottle, and ozone being a natural purifier, it offers several health benefits. In this document, you will see all the phases in which we developed the core ideas, interviewed potential consumers, established market hypothesis, ran focus groups in which the product's flavor and image were evaluated, and finally designed strategies to insert our product in a way that makes it competitive. Our water is targeted towards consumers from socioeconomic status A and B, and between ages of 18 and 50 years old, that reside in Lima and have a tendency to buy products that incentivize a healthy life and a sophisticated life style. Finally, in the document you'll be able to see the planning of activities such as: human resources, marketing, social responsibility, finances, and accounting, which show the viability of the business.
Trabajo de investigación

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Massons, Gassol Gerard. "Biofouling control in reverse osmosis membranes for water treatment". Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/461092.

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L’osmosi inversa (OI) és una de les tecnologies de purificació d'aigua més competitives. Els sistemes d'OI han evolucionat significativament en els últims anys per a proporcionar solucions reals i sostenibles als problemes relacionats amb l'aigua. Un dels principals obstacles que impedeix l'expansió en l'ús d'OI en la reutilització de l'aigua, és la pèrdua de rendiment que els elements d'OI experimenten a l'operar amb aigües contaminades. Aquest fenomen de embrutament continua sent un dels majors reptes a resoldre per elements de OI utilitzats en plantes industrials o de tractament d'aigües residuals. A causa de la complexitat d'estudiar aquests problemes en sistemes d'escala industrial, és necessari desenvolupar protocols per reproduir els efectes en equips de laboratori. Els efectes de l’embrutament solen apareixer després de diversos mesos. No obstant, per poder realitzar la recerca en un temps realista, el procés ha ser accelerat de forma controlada i el més realista possible. S'ha estudiat l'efecte de diferents variables operacionals en el desenvolupament de l’embrutament biològic. També s'ha avaluat el paper dels paràmetres de construcció de mòduls d'OI, provant en paral·lel diferents membranes i espaciadors, per millorar el disseny d'elements resistents al embrutament. Els resultats dels assaigs realitzats demostren clarament que diferents químiques de membrana poden proporcionar una reducció significativa en els nivells de embrutament. Tot i això, es va trobar que el principal contribuent al desenvolupament dels biofilms es el espaciador. El disseny de l'espaciador es va estudiar en detall per aconseguir un comportament equilibrat en mòduls d'OI que tracten aigües amb un risc d’embrutament biològic elevat. Es van probar espaciadors amb diferents espessors, separacions i angles. Alguns dissenys van mostrar avantatges en la perdua de pressió generada, així com en l'acumulació d’embrutament biològic i orgànic.
La osmosis inversa (OI) es una de las tecnologías de purificación de agua más competitivas. Los sistemas de OI han evolucionado significativamente en los últimos años para proporcionar soluciones reales y sostenibles a los problemas relacionados con el agua. Uno de los principales obstáculos que impide la expansión del uso de OI en la reutilización del agua es la pérdida de rendimiento que los elementos de OI experimentan al operar con aguas contaminadas. Este fenómeno de ensuciamiento sigue siendo uno de los mayores desafíos para los elementos de OI utilizados en plantas industriales o de tratamiento de aguas residuales. Debido a la complejidad de estudiar estos problemas en sistemas de escala industrial, es necesario desarrollar protocolos para reproducir los efectos en equipos de laboratorio. Los efectos del ensuciamiento suelen ocurrir después de varios meses. Sin embargo, para poder realizar la investigación en un tiempo realista, el proceso necesita ser acelerado de manera controlada y lo más realista posible. Se ha estudiado el efecto de diferentes variables operacionales en el desarrollo del ensuciamiento biológico. También se ha evaluado el papel de los parámetros de construcción de módulos de OI, probando en paralelo diferentes membranas y espaciadores, para mejorar el diseño de elementos resistentes al ensuciamiento. Los resultados de los ensayos realizados mostraron claramente que diferentes químicas de membrana pueden proporcionar una reducción significativa en los niveles de bioensuciamiento. Sin embargo, se encontró que el principal contribuyente al desarrollo de biofilms fue el espaciador. El diseño del espaciador se estudió en detalle para lograr un comportamiento equilibrado en módulos de OI que tratan aguas propensas al ensuciamiento biológico. Se ensayaron espaciadores con diferentes espesores, espaciamiento y ángulo. Algunos diseños mostraron ventajas en la perdida presión generada, así como en la acumulación de ensuciamiento biológico y orgánico.
Reverses osmosis (RO) filtration is one of the most competitive water purification technologies. RO systems have evolved significantly in the last years to provide real and sustainable solutions to water-related problems. One of the main hurdles that hinders RO expansion in water reuse, is the loss of performance that RO elements suffer when dealing with contaminated waters. This phenomenon known as fouling, remains to be one of the biggest challenges for RO elements used in industrial or wastewater treatment plants. Due to the complexity to study these problems in large scale systems, protocols need to be developed in order to mimic full-scale plants operation on a bench scale. Fouling problems are usually occurring after several month of operations. However, for a realistic time-scale research, the process needs to be accelerated in a controlled way and as similar as possible to what would be occurring naturally. The effect of different operating variables on biofouling development was studied. The role of RO module construction was also evaluated, testing different membranes and feed spacers side-by-side, to guide the improvements on the design of fouling resistant elements. The results from the trials performed clearly showed that different membrane chemistries can provide significant reduction in the levels of biofouling detected after operation. However, it was found that the main contributor to biofilm development was feed spacer. Large differences in the amount of biofouling generated could be associated with feed spacer presence. Feed spacer design was then studied in detail to achieve a balanced performance in spiral wound RO modules treating waters prone to biofouling. Feed spacers with various thickness, spacing and angle were tested and some designs showed advantages in pressure drops, as well as on biologic and organic fouling accumulation.

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41

Uematsu, Yuki. "Electro-osmosis of polymer solutions: linear and nonlinear behavior". 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215287.

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42

Hurd, Sarah M. "Low-pressure reverse osmosis membrane treatment of landfill leachate". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0025/MQ52299.pdf.

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43

Robinson, Michael Anthony. "Removal of organic contaminants from groundwater by reverse osmosis /". This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03142009-040729/.

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44

Lightfoot, Dennis G. (Dennis George). "Combined fields (electro-osmosis and pressure) dewatering of kelp". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68202.

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The world's brown marine algae, or kelps, have a great potential for agricultural use. Over 14 million tonnes of kelp are estimated to be available for harvesting every year, but only 6.3% is harvested, mostly for food products or alginate extraction. The inclusion of kelp in an animal's ration has been found by several researchers to have a beneficial effect on the animal's health and productivity. High concentrations of kelp in an animal's ration, however, can have detrimental effects on the animal's health due to toxic levels of certain inorganic salts.
By including a dewatering operation in the production of dried kelp meal, much of the soluble salts present in the kelp will be removed with the filtrate. The filtrate would also be valuable as a source of potassium, trace minerals, and phyto-hormones for crops. Energy costs for dewatering are also much lower than for drying. Because kelp is difficult to dewater using conventional methods, a combined fields technique using electro-osmosis and mechanical pressure was investigated.
Electric current and pressure were both found to have a significant positive effect on dewatering. Dewatering resulted in significantly lower ash and available carbohydrate fractions, while having no other significant effect on kelp meal composition. The combined fields dewatering resulted in significant total energy savings over conventional dewatering or drying alone.
The combined fields dewatering process was successfully scaled up to a continuous process using a prototype roller press. The press was able to produce a press cake with up to 32% solids. The continuous process resulted in significantly lower ash content and significantly higher protein. The total energy to produce kelp meal with the roller press was found to be about half of the energy required for drying alone.

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45

Ashhuby, Bashir Ali. "Biofouling studies on reverse osmosis desalination of hypersaline waters". Thesis, University of Sheffield, 2007. http://etheses.whiterose.ac.uk/3599/.

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Biological fouling of reverse osmosis (RO) membranes is affected by many factors, and it is not clearly understood, especially with respect to hypersaline waters. Biofouling minimisation requires understanding of the fundamentals of the biofilm development. It is also necessary to monitor biofilm development at various stages and its relation to concentration polarisation phenomena. The two main goals were to explore the biological diversity of a hypersaline lake called "Qabar-Onn"t located in the Sahara; and to better understand what biotic and abiotic factors govem biofouling of RO membranes treating hypersaline waters. Three halotolerant bacterial strains (Euhalothece species, BAAOOl and BAA002, and Halomonas pantelleriensis species, BAA003) were isolated from the lake using conventional culturing methods, and were identified based on 16S rRNA sequencing. Two isolated species, Eukalothece species BAAOOI and Halomonas pantelleriensis species BAA003 were used as model microorganisms to evaluate the potential of biofilm development on RO membranes. Salinity and surface roughness, which affect biofilm initiation and growth, were investigated. A novel, in-situ monitoring device was used to detect initiation of biofilm formation, and its relation to solutes and concentrations near RO membrane surfaces. The results showed that Qabar-Onn Lake is inhabited by a wide range of microorganisms, which seem to have a strong potential to adapt to the rapid increase in the lake salinity. In addition to salinity, pH also is limiting factor on biodiversity and microorganisms' dominance. Biofouling was strongly controlled by membrane characteristics and feed salinity. Lower surface roughness and low salinity contributed to less biofilm formation. Furthermore, the absence of monovalent anions (i. e. chloride) in the feed enhanced flux at low salinities; however, its absence severely decreased flux at higher salinities. Similarly, microorganisms present in the feed extremely enhanced the permeate flux at low salinities, however, at high salinities the flux decreased in the presence of microorganisms.

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46

Robinson, Michael A. "Removal of organic contaminants from groundwater by reverse osmosis". Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/41621.

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The performance of a poly(ether/urea) membrane has been evaluated in a full scale reverse osmosis system. A series of experiments were conducted with six aromatic compounds - anthracene, pyrene, fluorene, 2-chlorobiphenyl, 2,4,6 trichlorophenol, and pentachlorophenol- and four volatile compounds - trichloromethane, bromodichloromethane, dibromochloromethane, and trichloroethene - as single and multi-solute contaminants. The objectives of the experiments were to determine if poly(ether/urea) membranes could produce a permeate that met maximum contaminant levels (MCL) set by the Safe Drinking Water Act (SDWA) and to correlate membrane performance with physical/chemical properties of the solute contaminants. Aromatic contaminants were removed to concentrations below the current MCLs. However, volatile contaminants were not sufficiently rejected by the membrane to meet either the MCL for total trihalomethanes or trichloroethene. Sorption onto the poly(ether/urea) was found to occur for several of the aromatic compounds tested in this research. This prevented developing any relationship between membrane performance and physical/chemical properties of the solute.
Master of Science

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47

Malherbe, Gideon Francois. "Development and application of ultrafiltration and reverse osmosis membranes". Thesis, Cape Technikon, 1993. http://hdl.handle.net/20.500.11838/908.

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Thesis (Masters Diploma (Technology)--Cape Technikon, Cape Town,1993
Various experimental and established membranes were tested on industrial effluents. Ultrafiltration, reverse osmosis and nanofiltration membranes were used in various applications. Research was done on aspects such as the cleaning of fouled membranes, production quality control and process development. Polyvinyl alcohol ultra-thin-film reverse osmosis membranes were manufactured for the desalination of brackish water to a potable standard. The membranes were manufactured in the tubular configuration. Experimental ultrafiltration, reverse osmosis and nanofiltration membranes were tested on cooling water blowdown on a laboratory-scale. On-site testing was done directly on the effluent at a later stage. A s!udy was also conducted to determine the effect of gel-polarization on membrane performance. The gel-layer model was used to predict the limiting flux of specific membranes. Membrane processes were also applied in the fractionation of wine-lees to provide usable by-products such as yeast cells and potassium bitartrate. Ultrafiltration membranes operated in diafiltration mode were used to "wash" the slurry at different solid concentrations. The bitartrate-rich permeate collected from ultrafiltration was then concentrated using reverse osmosis and nanofiltration to allow subsequent precipitation of the product.

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48

Jingxi, Estella Zandile. "Forward osmosis : a desalination technology for the textile industry". Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2674.

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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017.
Similar to the energy crisis, the critical state of the water supply in South Africa (SA) is a combination of (i) resource exhaustion and pollution; (ii) increasing demand; and (iii) poor infrastructure. Despite its importance, water is the most poorly managed resource in the world. The disposal of industrial effluents contributes greatly to the poor quality of water. The textile industry consumes great quantities of water and produces enormous volumes of wastewater which requires appropriate treatment before being released into the environment. In an attempt to address the water issues, research globally has focused on advanced technologies such as desalination to increase limited pure water resources. The need for alternative desalination methods for the production of clean water from alternative water resources, such as seawater and brackish water, has gained worldwide attention. Reverse osmosis (RO) and Nanofiltration (NF) have been used as unswerving approaches to yield freshwater. Forward osmosis (FO) is a developing membrane technology that has increased substantial attention as a possible lower-energy desalination technology. However, challenges such as suitable FO membranes, membrane fouling, concentration polarisation, and the availability of effective draw solutions (DS), limit FO technology. FO is seeking more importance in novel areas where separation and recovery of the DS is not required. The aims of this study was to: i) identify alternative water resources and evaluate their potential as suitable feed solution (FS); ii) Identify dyes and evaluate their potential as suitable draw solutions (DS) at different concentrations; iii) assess the use of aquaporin biomimetic membrane and iv) assess a FO system for the production of dye solutions. Osmotic pressure (OP) is the pressure exerted by the flow of water through semi-permeable membrane, separating two solutions with different concentrations of solute. The DS should always have OP higher than the FS in order to achieve high water flux. Three basic dyes (i.e. Maxilon Turquoise, Red and Blue) and three reactive dyes (i.e. Carmine, Olive Green and Black) were selected, based on their common use in the SA textile industry. The respective dye samples were prepared at different concentrations and dye-to-salt mass ratios ranging from 1:10 to 1:60 and assessed for OP using a freezing point osmometer. A lab-scale FO unit was used for all the studies. Feed and draw channels were circulated in a counter-current flow at a volumetric flow rate of 600 mL/min. Feed solutions(FS) included deionised water (DI) as a control, brackish water (BW), synthetic seawater (SSW) and textile wastewater (TWW) collected from two textile factories. OP of the FS (DI, BW5, SSW and SW, Factory 1 and Factory 2) was 0, 414, 2761, 2579, 1505 and 3308 kPa, respectively. Basic Blue and Reactive Black generated a higher OP compared to other selected dyes in the study and were therefore selected to be used as DS at a 1:10 dye-to-salt ratio and 0.02 M concentration. An aquaporin biomimetic FO membrane (Aquaporin, Denmark) was used for all the experiments conducted in the FO mode.

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49

GUPTA, VINEET K. "EXPERIMENTAL AND THEORETICAL STUDIES IN REVERSE OSMOSIS AND NANOFILTRATION". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1061233200.

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50

Haupt, Anita y André Lerch. "Forward Osmosis Application in Manufacturing Industries: A Short Review". Molecular Diversity Preservation International (MDPI), 2018. https://tud.qucosa.de/id/qucosa%3A32479.

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Resumen

Forward osmosis (FO) is a membrane technology that uses the osmotic pressure difference to treat two fluids at a time giving the opportunity for an energy-efficient water and wastewater treatment. Various applications are possible; one of them is the application in industrial water management. In this review paper, the basic principle of FO is explained and the state-of-the-art regarding FO application in manufacturing industries is described. Examples of FO application were found for food and beverage industry, chemical industry, pharmaceutical industry, coal processing, micro algae cultivation, textile industry, pulp and paper industry, electronic industry, and car manufacturing. FO publications were also found about heavy metal elimination and cooling water treatment. However, so far FO was applied in lab-scale experiments only. The up-scaling on pilot- or full-scale will be the essential next step. Long-term fouling behavior, membrane cleaning methods, and operation procedures are essential points that need to be further investigated. Moreover, energetic and economic evaluations need to be performed before full-scale FO can be implemented in industries.

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