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Letteratura scientifica selezionata sul tema "Reverse osmosis process"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 1 agosto 2024

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Articoli di riviste sul tema "Reverse osmosis process"

Mann, J. "Reverse osmosis/ultrafiltration process principles". Chemical Engineering Journal 36, n. 3 (novembre 1987): 196. http://dx.doi.org/10.1016/0300-9467(87)80029-1.

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Ohya, H., K. Yajima e R. Miyashita. "Design of reverse osmosis process". Desalination 63 (gennaio 1987): 119–33. http://dx.doi.org/10.1016/0011-9164(87)90045-2.

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Salahudeen, Nurudeen. "Process simulation of modelled reverse osmosis for desalination of seawater". Water Practice and Technology 17, n. 1 (21 dicembre 2021): 175–90. http://dx.doi.org/10.2166/wpt.2021.127.

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Abstract (sommario):

Abstract Model equations for prediction of process parameters of reverse osmosis for desalination of seawater were developed via mathematical derivation from basic equations for the reverse osmosis process. A model equation relating the interfacial solute concentration () with the process pressure difference () was developed. Taking the of reverse osmosis as the basic independent variable, further model equations relating other process parameters such as the solute concentration polarity , water flux , osmotic pressure , water output rate (q), power density (Pd) and specific energy consumption (SEC) were developed. Simulation of hypothetical reverse osmosis data using Microsoft Excel Worksheet and Microsoft Windows 10 on a 64-bit operating system was carried out. Simulation results showed that the optimum fluid bulk concentration was = 0.0004 mole/cm3. The optimum rate of increase in the solute rejection factor per unit rise in ΔP was 0.45%. The optimum solute rejection factor was 97.6%. The optimum water output rate, specific energy consumption and power density were 103.2 L/h, 3.65 kWh/m3 and 6.09 W/m2, respectively.

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Tanaka, Yuji, Yohito Ito, Shigehisa Hanada e Tamotsu Kitade. "Environmental Friendly Seawater Reverse Osmosis Process". membrane 40, n. 2 (2015): 86–90. http://dx.doi.org/10.5360/membrane.40.86.

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Kimura, Shoji. "Transport Phenomena in Reverse Osmosis Process." membrane 21, n. 1 (1996): 2–8. http://dx.doi.org/10.5360/membrane.21.2.

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Chong, Tzyy Haur, Siew-Leng Loo e William B. Krantz. "Energy-efficient reverse osmosis desalination process". Journal of Membrane Science 473 (gennaio 2015): 177–88. http://dx.doi.org/10.1016/j.memsci.2014.09.005.

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Meares, P. "Reverse osmosis/ultra filtration process principles". Chemical Engineering Science 41, n. 9 (1986): 2453–54. http://dx.doi.org/10.1016/0009-2509(86)85104-1.

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Abdella, Dana L. "Reverse Osmosis Desalination". Marine Technology and SNAME News 31, n. 03 (1 luglio 1994): 195–200. http://dx.doi.org/10.5957/mt1.1994.31.3.195.

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Reverse osmosis (RO) desalination is a method of producing fresh water from seawater by a process similar to filtration, rather than by traditional evaporative distillation. A semipermeable membrane allows water molecules to pass through while blocking the passage of most other ions. The qualities of RO which make it attractive for naval and marine applications are its ability to operate on electric power alone, requiring no heat source; its comparatively low system weight to other methods of freshwater production at sea; and its ability to operate automatically, requiring minimal operator attention. RO's high operational reliability has contributed to its gain in popularity in recent years. RO is used for freshwater production in commercial industry and surface ship applications worldwide. The following research paper discusses RO desalination and presents RO as an alternative to conventional distillation for naval and marine use.

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Mohammed, Hiba A., Dawood E. Sachit e Mustafa Al-Furaiji. "APPLICATIONS AND CHALLENGES OF THE REVERSE OSMOSIS MEMBRANE PROCESS: A REVIEW". Journal of Engineering and Sustainable Development 27, n. 5 (1 settembre 2023): 630–46. http://dx.doi.org/10.31272/jeasd.27.5.6.

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Reverse osmosis is one of the most prevalent methods of generating potable water owing to its low power usage, excellent rates of contaminant removal, simple design, large output capacity, and much cheaper initial and maintenance costs than comparable alternatives. In this review, the most important published research related to the reverse osmosis process was reviewed. It was found that the majority of reported studies were related to using the reverse osmosis process for water desalination and wastewater treatment. Research has proven that the reverse osmosis process is a very effective method for desalinating water and treating industrial effluent containing heavy metals, organics, and other pollutants. Fouling was found to be one of the greatest obstacles encountered by the reverse osmosis method in water treatment, which raises operating costs due to the need for frequent cleaning, reduces the membrane's lifespan, and reduces the permeate flux. In general, microfiltration/ultrafiltration pretreatment and backwashing were among the most effective strategies suggested by researchers to reduce fouling and ensure the longevity and proper operation of the system.

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Saavedra, A., G. Bertoni, D. Fajner e G. C. Sarti. "Reverse osmosis treatment of process water streams". Desalination 82, n. 1-3 (agosto 1991): 249–66. http://dx.doi.org/10.1016/0011-9164(91)85192-w.

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Più fonti

Tesi sul tema "Reverse osmosis process"

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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Mane, Pranay P. "RO Process Optimization Based on Deterministic Process Model Coupled with Stochastic Cost Model". Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14486.

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A survey performed over existing two pilot-scale and two full-scale RO desalination facilities to study the current status of boron rejection showed a highest rejection 85% leading to permeate boron concentration of 0.52 mg/L, and recent studies predicted a cost increase due to incorporation of boron reduction systems. Mathematical models were developed to study the process performance and related cost implications. The deterministic process model was verified with pilot-scale experiment performed using a single spiral wound module and was later modified to represent the full-scale design options available to meet the required water quality criteria. Then the selected full-scale design options were simulated to predict their performance in terms of recovery and boron rejection. For cost analysis, to account for uncertainty probability models were developed for stochastic inputs to the cost estimation model and were used with operating parameters from the full-scale simulations to determine the expected total cost of water produced. Later, a sensitivity analysis was performed to observe the effect of change in uncertainty of inputs. Further, the applications of the deterministic process model are suggested.

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Chong, Brian S. H. "The removal of pesticides and heavy metals by reverse osmosis". Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/42126.

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Miyashita, Yu. "Removal of N-nitrosamine by Nanofiltration and Reverse Osmosis Membranes". Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14490.

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The rejections of selected N-nitrosamines by commonly used high-pressure nanofiltration (NF) and reverse osmosis (RO) membranes were quantitatively evaluated using a bench-scale cross-flow filtration apparatus. The selected nitrosamines included N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR), N-nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA), N-nitrosodi-n-butylamine (NDBA) and N-nitrosodiphenylamine (NDPHA). Nitrosamine rejections were evaluated under steady state at elevated feed concentrations, since NDMA rejections were found to be consistent with feed concentrations over three orders of magnitude. The steady-state nitrosamine rejections by NF membranes varied significantly, from 9 to 75%, depending on nitrosamine compounds and tested membranes. For hydrophilic compounds, rejections increased with increasing molecular weight. The nitrosamine rejections by brackish RO membranes reached as high as 97% for higher molecular weight nitrosamines. However, for low molecular weight nitrosamines such as NDMA, rejections as low as 54% were observed. This low level of rejections was attributed to diffusive solute transport being more effective than convective transport. Physicochemical properties such as molecular weight and aqueous diffusivity showed reasonable correlations with nitrosamine permeability constants.

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Schutte, Christiaan Frederik. "The feasibility of reverse osmosis as a water reclamation process with special reference to the rejection of organic compounds". Doctoral thesis, University of Cape Town, 1986. http://hdl.handle.net/11427/22470.

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This thesis deals with water reclamation and water reuse in the South African water supply context. The overall objective of the study is to assess the potential role and feasibility of reverse osmosis as a water reclamation process. In order to achieve this objective a number of separate desk, laboratory and pilot plant studies were conducted. It was concluded from the first desk study that a significant potential role exists for reverse osmosis in the South African water economy, mainly for the treatment of industrial effluents and, in the longer term, for the reclamation of water from sewage effluents and for the treatment of effluents and recycled water in indirect water reuse situations. A cost analysis showed that reverse osmosis could become economically viable in some water reuse situations in the near future provided that a productive membrane life of about three years can be achieved and that membrane fluxes can be maintained at design rates. These findings indicated the need for a pilot plant study to determine the effects of pretreatment and membrane cleaning on flux levels and rejection. A 50 m³/d pilot plant was designed and operated for a period of about six months from which it was concluded that acceptable flux levels can be maintained in tubular reverse osmosis plants treating well-oxidized activated sludge effluent with and without extensive pretreatment, provided both chemical and physical cleaning methods are employed. The desk study on the rejection of contaminants by reverse osmosis membranes indicated the need for a simple model that can be used to predict the removal of organic compounds of interest in water reclamation applications. It was concluded from a fundamental laboratory study, which included the evaluation of existing membrane models against laboratory data, that the solvophobic theory can be adapted in a simplified form to predict the transport of dissolved organic compounds in relatively non-polar reverse osmosis membranes. Based on reverse osmosis, diffusion, sorption and desorption data a mechanism is, furthermore, proposed for the transport of phenol in different membranes.

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Otto, Dietmar Norman. "The effect of forward flushing, with permeate, on gypsum scale formation during reverse osmosis treatment of CaSO4-rich water in the absence of anti-scalant". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95887.

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Thesis (MEng) -- Stellenbosch University, 2014.
ENGLISH ABSTRACT: When desalinating brackish water by reverse osmosis (RO) or other techniques, high overall water recoveries are essential to minimize brine production and the associated disposal costs thereof. As the overall water recovery increases, concentrations of sparingly soluble salts (e.g. barium sulphate, calcium sulphate) reach levels above saturation, especially near the membrane surface, drastically increasing the scaling propensity. Antiscalants are typically dosed into the feed water to prevent such scaling during RO desalination. However, the carry-over of antiscalant into the concentrate stream can complicate subsequent salt precipitation processes that may be used to increase overall water recovery. These precipitation techniques are sometimes used to reduce the levels of super-saturation in the RO concentrate prior to a subsequent RO desalination step. The purpose of this study was to assess the feasibility of reducing calcium sulphate scaling on RO membranes, by using periodic permeate flushing when feeding a lab-scale RO unit with a supersaturated calcium sulphate solution in the absence of anti-scalant. The overall water recovery was increased by recycling the concentrate, after an intermediate de-supersaturation step. This simulated a multiple-stage RO system, typical of processes used in high-recovery acid mine drainage (AMD) treatment plants. De-supersaturation of the concentrate intermediate was achieved with direct seeded gypsum precipitation, in the absence of any antiscalant. On the membrane surface inside the membrane unit, calcium sulphate concentrations greatly exceeded saturation levels – a combined consequence of the normal concentration process and the well-known surface-based concentration polarisation phenomenon. Therefore, periodic forward-flushing of the supersaturated solution from the membrane unit was performed with permeate. In theory, the periodic flushing removes the highly concentrated layer at the membrane surface during every flush, before scaling can occur. Various flushing regimes were evaluated to assess the effectiveness of the process. A lab-scale desalination unit with a 0.106 m2 flat sheet polyamide RO membrane was designed and constructed. The unit could operate at a feed rate of 12-14 L/h and at permeate fluxes of 12-24 LMH. Super-saturated feed solutions were prepared by mixing sodium sulphate and calcium chloride dihydrate salts with demineralised water, with an initial salinity of ± 5300 mg/L TDS, corresponding to a gypsum saturation index (SIg) of 1.2 for most experiments. The total production time, net permeate production and flux decline were used to compare the flushing efficiency in different experimental runs. Initial tests showed that scaling could be prevented (when operating the unit in full recycle mode, i.e. where both concentrate and permeate were recycled to feed), at flushing frequencies between 12 and 2.4 h-1, when the membrane feed and concentrate were slightly under-saturated (SIg = 0.9) and slightly super-saturated (SIg = 1.1) respectively. However, when switching the same system to non-flushing mode after 24 hours of operation, membrane scaling occurred within 2-3 hours, as indicated by a strong decline in flux. However, when operating the system in concentrate recycle mode (i.e. permeate is withdrawn) with super-saturated feed solutions (e.g. SIg = 1.2), and thus a notably more super-saturated solution in the membrane concentrate, scaling could not be prevented (albeit delayed for some time) with intermittent permeate flushing. A fractional 25-1 factorial design was used to determine which factors had the most significant effect on total production time and permeate production rate, testing five factors: 1) flushing frequency, 2) flushing volume, 3) permeate soak time, 4) permeate flux and 5) instantaneous recovery. The ANOVA analysis showed that total production times were, not surprisingly, primarily affected by the permeate flux, where operation at 24 LMH resulted in a lower net permeate production between 3.0 - 4.2 L, compared to 7.6 - 9.7 L at 12 LMH. Higher permeate fluxes clearly resulted in higher levels of concentration polarisation at the membrane surface, thus increasing the propensity for membrane scaling. Flushing frequency and instantaneous recovery also affected the net permeate production, where 6 h-1 and 10 % were the optimal values respectively within the range of test conditions. The lowest permeate production rate resulted in the highest net permeate volume production (i.e. also longest total production time), confirmed by a least squares regression. In summary: This study showed that periodic permeate flushing could delay the membrane scaling process. However, it failed to prevent membrane scaling completely when operating the system with supersaturated calcium sulphate solutions in the absence of antiscalants. The flushing technique effectively delayed the onset of precipitation, but scaling eventually occurred if the lab-scale RO system was operated in concentrate recycle mode with oversaturated feed solutions (SIg = 1.2). Additional experiments at different cross-flow velocities during permeate flushing, while using an optimised RO test cell flow channel design, are recommended for future studies.
AFRIKAANSE OPSOMMING: Gedurende die ontsouting van brakwater deur tegnieke soos tru-osmose (TO), is ŉ maksimum herwinning van water noodsaaklik om die produksie, en die gepaardgaande kostes van verwydering, van die sout/brak neweproduk te minimeer. Soos die herwinning van water verhoog, so ook verhoog die konsentrasie van moeilik-oplosbare soute (soos bariumsulfaat, kalsiumsulfaat) in die sout konsentraat stroom, totdat die soute uiteindelik superversadiging bereik. Hierdie superversadiging gebeur veral naby die membraanoppervlak, waar dit lei tot ŉ verhoogde kans van presipitasie en skaalvorming. Om dit te voorkom word die voerwater na ŉ TO stelsel tipies gedoseer met antiskaalmiddels. Hierdie antiskaalmiddels verlaat die stelsel saam met die konsentraat, waar hulle gevolglike die presipitasie van soute bemoeilik. Presipitasie van soute uit die konsentraat kan tipies gebruik word om die vlak van superversadiging in die konsentraat te verlaag, waarna verdere TO behandeling gebruik word om selfs ŉ hoër algehele waterherwinning te bewerkstellig. Die doel van hierdie studie was om die vatbaarheid van die vermindering van kalsiumsulfaat (gips) skaalvorming in die afwesigheid van antiskaalmiddels op TO membrane te toets. Dit is bewerkstellig deur ŉ laboratoriumskaal TO eenheid te voer met ŉ superversadigde kalsiumsulfaat oplossing en die membraan periodies met skoon produkwater (permeaat) te was. Die algehele waterherwinning is verhoog deur met ŉ tussenstap die versadigingsvlak van gips in die konsentraat te verlaag, waarna dit hersirkuleer is na die voertenk. Sodoende is ŉ multi-stadium TO stelsel nageboots, soos dit tipies in hoë herwinningsaanlegte, soos met die herwinning van suur mynwater (E: acid mine drainage, AMD), gebruik word. ŉ Verlaging in superversadiging van die konsentraat in die tussenstap is behaal deur die konsentraat direk aan gipskristalle bloot te stel om presipitasie te bewerkstellig in die afwesigheid van enige antiskaalmiddels. Gedurende eksperimente het die soutkonsentrasie op die membraanoppervlak in die TO eenheid superversadigingsvlakke vêr oorskry, as gevolg van die natuurlike konsentrasie proses en die bekende konsentrasie polarisasie oppervlaksverskynsel. Om hierdie superversadiging teen te werk is periodiese saamstroom spoeling van die membraan met skoon produkwater uitgevoer. In teorie het die periodiese spoeling die hoogs gekonsentreerde oplossing van die membraan oppervlak verwyder voor skaalvorming kan plaasvind. Verskillende spoelpatrone is ondersoek om die doeltreffendheid van die spoeling te bepaal. Om die eksperimente uit te voer is ŉ laboratoriumskaal ontsoutingsaanleg met ŉ maklik verwyderbare 0.106 m2 plat-vel poli-amied TO membraan ontwerp en gebou. Die aanleg kan vloeistof voertempo’s tussen 12-24 L/h hanteer en skoon produkwater teen 12-24 LHM lewer. Die superversadigde voer oplossings, soos gebruik in die meerderheid van die eksperimentes is voorberei deur natriumsulfaat en kalsiumchloried-dihidraat soute te meng in gedemineraliseerde water, tot ŉ soutgehalte van ± 5300 mg/L TDS bereik is. Hierdie soutgehalte stem ooreen met ŉ gips versadigingsindeks (E: gypsum saturation index, SIg) van 1.2. Die skoon produkwater totale produksietyd en netto produksie, asook die membraan vloed afname, is gebruik as veranderlikes om die spoel doeltreffendheid tussen eksperimentele lopies te vergelyk. Aanvanklike toetse het getoon dat skalering voorkom is by effens onderversadigde (SIg = 0.9) en effens superversadigde (SIg = 1.1) voer oplossings met die onderskeie spoel frekwensies van 12 en 2.4 h-1, (terwyl die aanleg in algehele hersirkulasie bedryf is, m.a.w. wanneer beide die konsentraat en produkwater gedurig na die voertenk hersirkuleer word). ŉ Effens-superversadigde eksperiment is ook sonder spoeling uitgevoer vir 24 uur. In hierdie geval het skaalvorming binne twee tot drie uur gebeur, soos bevestig deur ŉ skerp afname in die membraan vloed. Skaalvorming kon nie verhoed word terwyl die aanleg bedryf word met superversadigde (SIg = 1.2) voeroplossings en slegs konsentraat hersirkulasie nie (m.a.w. skoon produkwater word opgevang), alhoewel skaalvorming vertraag kon word. Hierdie operasie het tot beduidend meer gekonsentreerde oplossings in die membraan gelei. Om te bepaal watter faktore die grootste invloed op totale produksietyd en netto produksie van skoon produkwater het, is ŉ fraksionele faktoriaalontwerp van 25-1 uitgelê wat vyf faktore toets, naamlik: 1) spoel frekwensie, 2) spoel volume, 3) skoon produkwater weektyd, 4) membraanvloed en 5) oombliklike herwinning. ŉ AVOVA analise het getoon dat totale produksietyd hoofsaaklik deur membraanvloed beïnvloed is, soos verwag kan word. Dit word gestaaf deurdat die aanleg, bedryf teen 24 LMH, slegs 3 - 4.2 L netto produkwater gelewer het, teenoor 7.6 - 9.7 L by 12 LMH. Hoër membraan vloedtempo’s het tot hoër vlakke van konsentrasie polarisasie op die membraanoppervlak gelei, wat ŉ groter neiging tot skaalvorming tot gevolg gehad het. Spoelfrekwensie en oombliklike herwinning het ŉ invloed op die netto produksie van skoon produkwater gehad, met 6 h-1 en 10 % as die onderskeie optimale waardes. ŉ Kleinstekwadraat regressie het aangedui dat die laagste produksietempo van skoon produkwater die hoogste netto produksie van skoon produkwater gelewer het, (asook die langste produksietyd). In opsomming: Hierdie studie het getoon dat gereelde spoeling met skoon produkwater die membraan skaalproses kan vertraag. Gedurende bedryf met superversadigde kalsiumsulfaat oplossings sonder enige antiskaalmiddels is daar gevind dat skaalvorming nie geheel en al vermy kon word nie. Die spoeltegniek, soos gebruik in hierdie studie, het die aanvang van skaalvorming in die laboratorium skaal TO eenheid vertraag, maar bedryf met konsentraat hersirkulasie en superversadigde oplossings (SIg = 1.2) het steeds skaal gevorm. Bykomende eksperimente teen verskeie kruisvloei snelhede gedurende die spoel stap word aanbeveel vir toekomstige studies.

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Gorman, Craig T. "Initial measurements and test system development for evaluation of a novel, hybrid reverse osmosis-electrodialysis process". Diss., Connect to online resource, 2005. http://wwwlib.umi.com/cr/colorado/fullcit?p1428735.

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Jeffery, Samantha. "In-Plant and Distribution System Corrosion Control for Reverse Osmosis, Nanofiltration, and Anion Exchange Process Blends". Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5951.

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The integration of advanced technologies into existing water treatment facilities (WTFs) can improve and enhance water quality; however, these same modifications or improvements may adversely affect finished water provided to the consumer by public water systems (PWSs) that embrace these advanced technologies. Process modification or improvements may unintentionally impact compliance with the provisions of the United States Environmental Protection Agency's (USEPA's) Safe Drinking Water Act (SDWA). This is especially true with respect to corrosion control, since minor changes in water quality can affect metal release. Changes in metal release can have a direct impact on a water purveyor's compliance with the SDWA's Lead and Copper Rule (LCR). In 2010, the Town of Jupiter (Town) decommissioned its ageing lime softening (LS) plant and integrated a nanofiltration (NF) plant into their WTF. The removal of the LS process subsequently decreased the pH in the existing reverse osmosis (RO) clearwell, leaving only RO permeate and anion exchange (AX) effluent to blend. The Town believed that the RO-AX blend was corrosive in nature and that blending with NF permeate would alleviate their concern. Consequently, a portion of the NF permeate stream was to be split between the existing RO-AX clearwell and a newly constructed NF primary clearwell. The Town requested that the University of Central Florida (UCF) conduct research evaluating how to mitigate negative impacts that may result from changing water quality, should the Town place its AX into ready-reserve. The research presented in this document was focused on the evaluation of corrosion control alternatives for the Town, and was segmented into two major components: 1. The first component of the research studied internal corrosion within the existing RO clearwell and appurtenances of the Town's WTF, should the Town place the AX process on standby. Research related to WTF in-plant corrosion control focused on blending NF and RO permeate, forming a new intermediate blend, and pH-adjusting the resulting mixture to reduce corrosion in the RO clearwell. 2. The second component was implemented with respect to the Town's potable water distribution system. The distribution system corrosion control research evaluated various phosphate-based corrosion inhibitors to determine their effectiveness in reducing mild steel, lead and copper release in order to maintain the Town's continual compliance with the LCR. The primary objective of the in-plant corrosion control research was to determine the appropriate ratio of RO to NF permeate and the pH necessary to reduce corrosion in the RO clearwell. In this research, the Langelier saturation index (LSI) was the corrosion index used to evaluate the stability of RO:NF blends. Results indicated that a pH-adjusted blend consisting of 70% RO and 30% NF permeate at 8.8-8.9 pH units would produce an LSI of +0.1, theoretically protecting the RO clearwell from corrosion. The primary objective of the distribution system corrosion control component of the research was to identify a corrosion control inhibitor that would further reduce lead and copper metal release observed in the Town's distribution system to below their respective action limits (ALs) as defined in the LCR. Six alternative inhibitors composed of various orthophosphate and polyphosphate (ortho:poly) ratios were evaluated sequentially using a corrosion control test apparatus. The apparatus was designed to house mild steel, lead and copper coupons used for weight loss analysis, as well as mild steel, lead solder and copper electrodes used for linear polarization analysis. One side of the apparatus, referred to as the “control condition,” was fed potable water that did not contain the corrosion inhibitor, while the other side of the corrosion apparatus, termed the “test condition,” was fed potable water that had been dosed with a corrosion inhibitor. Corrosion rate measurements were taken twice per weekday, and water quality was measured twice per week. Inhibitor evaluations were conducted over a span of 55 to 56 days, varying with each inhibitor. Coupons and electrodes were pre-corroded to simulate existing distribution system conditions. Water flow to the apparatus was controlled with an on/off timer to represent variations in the system and homes. Inhibitor comparisons were made based on their effectiveness at reducing lead and copper release after chemical addition. Based on the results obtained from the assessment of corrosion inhibitors for distribution system corrosion control, it appears that Inhibitors 1 and 3 were more successful in reducing lead corrosion rates, and each of these inhibitors reduced copper corrosion rates. Also, it is recommended that consideration be given to use of a redundant single-loop duplicate test apparatus in lieu of a double rack corrosion control test apparatus in experiments where pre-corrosion phases are implemented. This recommendation is offered because statistically, the control versus test double loop may not provide relevance in data analysis. The use of the Wilcoxon signed ranks test comparing the initial pre-corroding phase to the inhibitor effectiveness phase has proven to be a more useful analytical method for corrosion studies.
M.S.Env.E.
Masters
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Environmental Engineering

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Al-Obaidi, Mudhar A. A. R. "Modelling, Simulation, and Optimisation of Reverse Osmosis Process with Application in Wastewater Treatment and Food Processing". Thesis, University of Bradford, 2018. http://hdl.handle.net/10454/17345.

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Reverse Osmosis (RO) is a membrane-based separation process applied in several industrial and food processing applications. In this research, performance of RO process is investigated in respect of two applications (a) wastewater treatment (b) concentration fruit juices using model-based techniques. For this purpose, a number of models (both 1 and 2-dimensional steady state and dynamic) for spiral wound RO process are developed based on Solution-Diffusion model and Irreversible Thermodynamic model. The models are validated against actual experimental data reported in the literature before being used in further simulation and optimisation studies for both wastewater treatment and fruit juice concentration. Wastewater effluents of many industrial applications contain a variety of micro-pollutants and highly-toxic compounds, which are released into a variety of water resources. Such pollutants not only disrupt the biological ecosystem, but they also pose a real threat to the water supply for human consumption and to the aquatic ecosystems. The earlier chapters of the thesis evaluate the performance of RO process in terms of removal efficiency of toxic compounds such as chlorophenol, N-nitrosamine, etc. from wastewater. The effect of several operating parameters such as feed pressure, concentration, flow rate and temperature, on the performance of RO process are evaluated. Also, suitability of a number of different RO configurations for efficient removal of toxic compounds are evaluated. For example, (a) two-stage/two-pass RO design synthesis of RO network for the removal of chlorophenol (b) multistage multi-pass RO process with and without energy recovery option for the removal of N-nitrosamine are investigated. The dynamic response of the RO process for step changes in the operating parameters is investigated for the removal of phenolic compounds. Finally, in the context of wastewater treatment, a case study with multi compounds contaminants is suggested where a multi-objective optimisation problem has achieved the optimum rejection of all the compounds and recovery rate. In respect of food processing, RO has been considered as a prominent process in fruit juice concentration due to its ability to effectively retain the flavour, sensory, aroma and nutritional characteristics and concentrate the juice. This research elucidates one example of apple juice concentration process and focuses on highlighting successful modelling and optimisation methodology. This in turn provides an efficient method of RO process for concentrating apple juice by improving the reliability and efficiency of the underlying separation and concentration process.
Ministry of High Education and Scientific Research of Iraq

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Takaidza, Samkeliso. "The effects of biofouling on a reverse osmosis membrane purification system at Sasol, Sasolburg". Thesis, Vaal University of Technology, 2011. http://hdl.handle.net/10352/452.

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M. Tech. (Biotechnology, Department of Biosciences, Faculty of Applied and Computer Sciences), Vaal University of Technology.
Reverse osmosis (RO) membranes are widely used in water purification. The presence of biofilms in water and industrial water purification systems is prevalent. As a result, biofouling which is a biofilm problem causes adverse effects on reverse osmosis process, which include flux decline, shorter membrane lifetime and an increase in energy consumption The effect of biofouling on RO membranes was investigated at a water treatment facility at Sasol, Sasolburg by investigating the quality of water purified by the RO system and the extent of fouling that is attributed to biofouling. Chemical and microbiological data was averaged based on the results obtained from water analysis and samples from a fouled membrane. Bacteriological plate counts ranged between log 1.5 to 4 cfu/ml in water samples and log 3.9 to 4.5 cfu/cm2 on biofilm from the membrane surface. Water analysis indicated a high conductivity of 121 µS/cm in the feed and 81 ppm of the TDS, whereas in the permeate conductivity was found to be around 6 µS/cm and 3.8 ppm of the TDS. This indicated that components present in the feed were retained by the membrane. This was supported by membrane autopsy which showed that the bacteria and elements found in the feedwater were also present on the membrane surface, hence contributing to fouling. An average of 33% of cellular ATP was measured on the biofilm from membrane sample, showing that the fouling bacteria are metabolically active in situ. The results clearly indicated that an important biological activity occurred at the membrane surface.

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Libri sul tema "Reverse osmosis process"

Center for Environmental Research Information (U.S.), a cura di. Reverse osmosis process. Cincinnati, OH: Center for Environmental Research Information, National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 1996.

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Sourirajan, S. Reverse osmosis: Ultrafiltration process principles. Ottawa, [Ontario]: National Research Council Canada, 1985.

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1936-, Matsuura Takeshi, e National Research Council Canada, a cura di. Reverse osmosis, ultrafiltration process principles. Ottawa, Canada: National Research Council Canada, 1985.

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Sourirajan, S. Reverse osmosis/ultrafiltration process principles. Ottawa, Canada: National Research Council Canada, 1985.

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United States. Environmental Protection Agency. Office of Research and Development., Center for Environmental Research Information (U.S.) e National Risk Management Research Laboratory (U.S.), a cura di. Capsule report: Reverse osmosis process. Cincinnati, Ohio: Center for Environmental Research Information, National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, 1996.

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Bergman, Robert. Reverse osmosis and nanofiltration. 2^a ed. Denver, CO: American Water Works Association, 2007.

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Ltd, CH2M Hill Engineering. Reverse osmosis, pilot program at Dare Candy. [Toronto]: Queen's Printer for Ontario, 1992.

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1947-, Parekh Bipin S., a cura di. Reverse osmosis technology: Applications for high-purity-water production. New York: M. Dekker, 1988.

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Lawler, Desmond F. Enhanced reverse osmosis systems: Intermediate treatment to improve recovery. Denver, Colo: Water Research Foundation, 2011.

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Eisenhauer, Roy J. Plugging factor monitor membrane quality acceptance: Flow rate test. Denver, Colo: Applied Sciences Branch, Research and Laboratory Services Division, Denver Office, U.S. Dept. of the Interior, Bureau of Reclamation, 1991.

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Capitoli di libri sul tema "Reverse osmosis process"

Wilf, Mark. "The Reverse Osmosis Process". In Desalination, 155–204. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2014. http://dx.doi.org/10.1002/9781118904855.ch3.

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Ludwig, Heinz. "Reverse Osmosis Membrane System: Core Process of SWRO". In Reverse Osmosis Seawater Desalination Volume 1, 315–739. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-81931-6_5.

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Ludwig, Heinz. "Seawater Reverse Osmosis (SWRO) Plant: General System Configuration, Basic Design Parameters and Conditions, and Overall Planning Process". In Reverse Osmosis Seawater Desalination Volume 1, 205–314. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-81931-6_4.

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Rautenbach, R., e I. Janisch. "Reverse Osmosis for the Separation of Organics from Aqueous Solutions". In Process Technologies for Water Treatment, 25–41. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4684-8556-1_3.

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Mohammed, Moumni, e Massour El Aoud Mohamed. "Control of Reverse Osmosis Process at a Brackish Water Desalination Station". In The Proceedings of the International Conference on Electrical Systems & Automation, 143–54. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-0039-6_12.

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Hemanth Kumar, M. B., e B. Saravanan. "Compressed Air Energy Storage Driven by Wind Power Plant for Water Desalination Through Reverse Osmosis Process". In Advances in Intelligent Systems and Computing, 145–54. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-15-0035-0_12.

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Gadge, Padmanabh Arun, e Shubhangi Gurway. "Improving reverse osmosis process in zero liquid discharge using Taguchi optimization method in alcohol production industry". In Recent Advances in Material, Manufacturing, and Machine Learning, 777–84. London: CRC Press, 2024. http://dx.doi.org/10.1201/9781003450252-94.

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Zocchi, Roberto, Gianluca Brevigliero, Federico Arlati, Alma Rodriquens, Mariachiara D’Aniello e Khadija Ajmi. "Advanced Process for PFAS Removal from a Leachate Landfill: On-site Plant Based on Reverse Osmosis and Evaporation Technology". In Advances in Science, Technology & Innovation, 231–35. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-00808-5_53.

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Xue, Xingfu. "Engineering practice study on the treatment of domestic garbage leachate based on two-stage disc tube reverse osmosis combined process". In Advances in Food Safety and Environmental Engineering, 99–106. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003318514-17.

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Weber, B., e F. Holz. "Landfill Leachate Treatment by Reverse Osmosis". In Effective Industrial Membrane Processes: Benefits and Opportunities, 143–54. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3682-2_10.

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Atti di convegni sul tema "Reverse osmosis process"

Gulied, Mona Hersi, Ahmed Al Nouss, Tasneem ElMakki, Fathima Sifani Zavahir e Dong Suk han. "Feasibility and Cost Optimization study of Osmotic Assisted Reverse Osmosis Process for Brine Management". In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0031.

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Due to the excessive demand to desalinate seawater to satisfy the domestic need in Qatar, it was needed to develop safe and cost effective desalination processes with the consideration of stringent regulation for water quality production and wastewater/brine discharge quality. The direct disposal of brines to the environment raised potential negative impact to the aquatic system and therefore the best practice is to minimize the volume of brine production and reuse it for beneficiary application. Several brine-dewatering techniques include both evaporative and non-evaporative approaches, which are capable to dewater high salinity brines with 50-350 g/L of total dissolved solids (TDS). The commonly adopted technology for dewatering brine is mechanical vapor compression that is known for its significant energy consumption up to 25 kWh/m3 of produced water for 50% of water recovery1. Non-evaporative membrane base technologies are a promising approach to dewater brines with minimum energy usage. Osmotically assisted reverse osmosis (OARO) is an advance membrane based technology for energy efficient and high recovery desalination of saline brine. OARO differ from reverse osmosis (RO) by adding saline sweep on permeate side to reduce osmotic pressure difference across the membrane to generate more water flux. The ongoing research work are based on mathematical/numerical approach that focuses on finding the optimum OARO configuration, inlet hydraulic pressure to avoid membrane burst and cost analysis. However, most of these studies are conducted by considering ideal conditions. In this study, an algorithm for simulating OARO process based on MATLAB and Aspen Plus to model membrane calculation and to design process configuration is considered to the effect of concentration polarization (CP) and reverse solute flux (RSF). The objective is to study the effect of inlet feed concentration and flowrate, sweep concentration and flowrate, inlet hydraulic pressure, number of stages, membrane size and characteristics and module configuration flow. In addition, technical economic analysis to evaluate the economic feasibility of OARO process. The stopping criteria of this model is the quality of water permeating at the feasible operating conditions and the cost. This model demonstrated high potential simulating OARO process to be used as a palate form for the user to predict the behavior of the process by varying operating conditions to desired outcomes.

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Bartman, Alex R., Charles W. McFall, Panagiotis D. Christofides e Yoram Cohen. "Model predictive control of feed flow reversal in a reverse osmosis desalination process". In 2009 American Control Conference. IEEE, 2009. http://dx.doi.org/10.1109/acc.2009.5160150.

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Maure, Osniman, e Sudi Mungkasi. "On Modelling of Water Distillation in a Reverse Osmosis Process". In Proceedings of the 2nd International Conference of Science and Technology for the Internet of Things, ICSTI 2019, September 3rd 2019, Yogyakarta, Indonesia. EAI, 2020. http://dx.doi.org/10.4108/eai.20-9-2019.2292098.

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Usta, Mustafa, Ali E. Anqi, Michael Morabito, Alaa Hakim, Mohammed Alrehili e Alparslan Oztekin. "Computational Study of Reverse Osmosis Desalination Process: Hollow Fiber Module". In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70884.

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Reverse Osmosis (RO) is a process whereby solutes are removed from a solution by means of a semipermeable membrane. Providing access to clean water is one of our generation’s grand engineering challenges, and RO processes are taking center stage in the global implementation of water purification technologies. In this work, computational fluid dynamics simulations are performed to elucidate the steady state phenomena associated with the mass transport of solution through cylindrical hollow fiber membranes in hopes of optimizing RO technologies. The Navier-Stokes and mass transport equations are solved numerically to determine the flow field and solute concentration distribution in the hollow fiber membrane bank, which is a portion of the three-dimensional feed channel containing a small collection of fibers. The k-ω Shear Stress Transport turbulence model is employed to characterize the flow field. Special attention is given to the prediction of water passage through hollow fiber membranes by the use of the solution-diffusion model, which couples the salt gradient, water flux, and local pressure at the membrane surface. This work probes hollow fiber membrane arrangement in the feed channel by considering inline and staggered alignments. Feed flow rates for Reynolds number values ranging between 400 and 1000 are considered. Increased momentum mixing within the feed channel solution can substantially enhance the system efficiency, and hollow fiber membrane arrangements and feed flow rates dictate the momentum mixing intensity. Velocity and vorticity iso-surfaces of the flow domain are presented in order to assess the momentum mixing achieved with various hollow fiber membrane arrangements and flow rates. The total water permeation rate per hour is calculated to compare system efficiencies, and the coefficient of performance is calculated to compare membrane performance relative to the necessary power input, both for the various hollow fiber membrane arrangements and feed flow rates.

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McFall, Charles W., Alex Bartman, Panagiotis D. Christofides e Yoram Cohen. "Control of a reverse osmosis desalination process at high recovery". In 2008 American Control Conference (ACC '08). IEEE, 2008. http://dx.doi.org/10.1109/acc.2008.4586825.

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Golabi, Arash, Abdelkarim Erradi, Hazim Qiblawey, Ashraf Tantawy, Ahmed Bensaid e Khaled Shaban. "Reverse osmosis desalination process modeling and simulation with membrane fouling". In INTERNATIONAL CONFERENCE ON ELECTRONICS, ENGINEERING PHYSICS, AND EARTH SCIENCE. AIP Publishing, 2024. http://dx.doi.org/10.1063/5.0200360.

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Lee, Sangho, e Richard M. Lueptow. "Space Mission Wastewater Recovery System Using Rotating Reverse Osmosis: Process Simulation". In International Conference On Environmental Systems. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2002. http://dx.doi.org/10.4271/2002-01-2528.

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MOHAMMED, MOUMNI, e MOHAMED MASSOUR EL AOUD. "Modeling of reverse osmosis process at a brackish water desalination station". In 2021 7th International Conference on Optimization and Applications (ICOA). IEEE, 2021. http://dx.doi.org/10.1109/icoa51614.2021.9442632.

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Nasib, Amira Mohd, Nuratiqah Baharudin, Nora Jullok, Syahmie Rasidi e Juhana Jaafar. "Fabrication of biodegradable Polylactic Acid (PLA) membrane for reverse osmosis process". In THE PROCEEDING OF THE 1ST INTERNATIONAL CONFERENCE OF CHEMICAL SCIENCE, ENGINEERING AND TECHNOLOGY. AIP Publishing, 2023. http://dx.doi.org/10.1063/5.0115854.

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Habib, Abdulelah, Vahraz Zamani e Jan Kleissl. "Solar Desalination System Model for Sizing of Photovoltaic Reverse Osmosis (PVRO)". In ASME 2015 Power Conference collocated with the ASME 2015 9th International Conference on Energy Sustainability, the ASME 2015 13th International Conference on Fuel Cell Science, Engineering and Technology, and the ASME 2015 Nuclear Forum. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/power2015-49386.

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The focus of this paper is to optimize the solar energy utilization in the water desalination process. Due to variable nature of solar energy, new system design is needed to address this challenge. Here, reverse osmosis units, as the electrical loads, are considered as an ON/OFF units to track these solar energy variations. Reverse osmosis units are different in sizes and numbers. Various combinations of reverse osmosis units in size and capacity provide different water desalination system performances. To assess each scenario of reverse osmosis units, the total capital cost and operation and maintenance (O&M) cost are considered. The implemented optimization algorithm search all of the possible scenarios to find the best solution. This paper deploys the solar irradiance data which is provided from west coast (Red Sea) of Saudi Arabia for model construction and optimization algorithm implementation.

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Rapporti di organizzazioni sul tema "Reverse osmosis process"

Wang, Hua. Membrane Bioreactor/Ultra Low Energy Reverse Osmosis Membrane Process for Forward Operating Base Wastewater Reuse. Fort Belvoir, VA: Defense Technical Information Center, agosto 2014. http://dx.doi.org/10.21236/ada619412.

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Kalman, Joseph, e Maryam Haddad. Wastewater-derived Ammonia for a Green Transportation Fuel. Mineta Transportation Institute, luglio 2022. http://dx.doi.org/10.31979/mti.2021.2041.

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The energy-water nexus (i.e., availability of potable water and clean energy) is among the most important problems currently facing society. Ammonia is a carbon-free fuel that has the potential to reduce the carbon footprint in combustion related vehicles. However, ammonia production processes typically have their own carbon footprint and do not necessarily come from sustainable sources. This research examines wastewater filtration processes to harvest ammonia for transportation processes. The research team studied mock wastewater solutions and was able to achieve ammonia concentrations above 80%(nanofiltration) and 90% (reverse osmosis). The research team also investigated the influence of transmembrane pressure and flow rates. No degradation to the membrane integrity was observed during the process. This research used constant pressure combustion simulations to calculate the ignition delay times for NH3-air flames with expected impurities from the wastewater treatment processes. The influence of impurities, such as H2O, CO, CO2, and HCl, were studied under a range of thermodynamic conditions expected in compression ignition engines. The team observed carbon monoxide and water vapor to slightly decrease (at most 5%) ignition delay time, whereas HCl, in general, increased the ignition delay. The changes to the combustion chemistry and its influence of the reaction mechanism on the results are discussed. The experimental wastewater treatment study determined that reverse osmosis produced higher purity ammonia. The findings of the combustion work suggest that ignition delays will be similar to pure ammonia if HCl is filtered from the final product.

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Kalman, Joseph, e Maryam Haddad. Wastewater-derived Ammonia for a Green Transportation Fuel. Mineta Transportation Institute, luglio 2022. http://dx.doi.org/10.31979/mti.2022.2041.

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Husson, Scott M., Viatcheslav Freger e Moshe Herzberg. Antimicrobial and fouling-resistant membranes for treatment of agricultural and municipal wastewater. United States Department of Agriculture, gennaio 2013. http://dx.doi.org/10.32747/2013.7598151.bard.

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This research project introduced a novel membrane coating strategy to combat biofouling, which is a major problem for the membrane-based treatment of agricultural and municipal wastewaters. The novelty of the strategy is that the membrane coatings have the unique ability to switch reversibly between passive (antifouling) and active (antimicrobial) fouling control mechanisms. This dual-mode approach differs fundamentally from other coating strategies that rely solely on one mode of fouling control. The research project had two complementary objectives: (1) preparation, characterization, and testing of dual-mode polymer nanolayers on planar surfaces and (2) evaluation of these nanolayers as membrane modifiers. The first objective was designed to provide a fundamental understanding of how polymer nanolayer chemistry and structure affect bacterial deposition and to demonstrate the reversibility of chemical switching. The second objective, which focused on membrane development, characterization, and testing, was designed to demonstrate methods for the production of water treatment membranes that couple passive and active biofouling control mechanisms. Both objectives were attained through synergistic collaboration among the three research groups. Using planar silicon and glass surfaces, we demonstrated using infrared spectroscopy that this new polymer coating can switch reversibly between the anti-fouling, zwitterion mode and an anti-microbial, quaternary amine mode. We showed that switching could be done more than 50 times without loss of activity and that the kinetics for switching from a low fouling zwitterion surface to an antimicrobial quaternary amine surface is practical for use. While a low pH was required for switching in the original polymer, we illustrated that by slightly altering the chemistry, it is possible to adjust the pH at which the switching occurs. A method was developed for applying the new zwitterionic surface chemistry onto polyethersulfone (PES) ultrafiltration membranes. Bacteria deposition studies showed that the new chemistry performed better than other common anti-fouling chemistries. Biofilm studies showed that PESultrafiltration membranes coated with the new chemistry accumulated half the biomass volume as unmodified membranes. Biofilm studies also showed that PES membranes coated with the new chemistry in the anti-microbial mode attained higher biofilm mortality than PES membranes coated with a common, non-switchablezwitterionic polymer. Results from our research are expected to improve membrane performance for the purification of wastewaters prior to use in irrigation. Since reduction in flux due to biofouling is one of the largest costs associated with membrane processes in water treatment, using dual-mode nanolayer coatings that switch between passive and active control of biofouling and enable detachment of attached biofoulants would have significant economic and societal impacts. Specifically, this research program developed and tested advanced ultrafiltration membranes for the treatment of wastewaters. Such membranes could find use in membrane bioreactors treating municipal wastewater, a slightly upgraded version of what presently is used in Israel for irrigation. They also may find use for pretreatment of agricultural wastewaters, e.g., rendering facility wastewater, prior to reverse osmosis for desalination. The need to desalinate such impaired waters water for unlimited agricultural use is likely in the near future.

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