scispace - formally typeset
Search or ask a question
Topic

Reverse osmosis

About: Reverse osmosis is a research topic. Over the lifetime, 20780 publications have been published within this topic receiving 299185 citations. The topic is also known as: RO.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, a numerical model is presented for a two-stage seawater reverse osmosis (SWRO) desalination unit with spiral-wound modules, which takes into account the longitudinal variation of the velocity, the pressure, and the salt concentration in the membrane modules.
Abstract: A numerical model is presented for a two-stage seawater reverse osmosis (SWRO) desalination unit with spiral-wound modules. The model, which is based on the mass and momentum transport equations, takes into consideration the longitudinal variation of the velocity, the pressure, and the salt concentration in the membrane modules. This model was calibrated with the field data of a 600 m3/day SWRO unit of the desalination plant of Porto Santo Island (Portugal) and was used to optimize the module configuration and the operating conditions of a medium-sized SWRO with spiral-wound modules. For a typical reverse osmosis (RO) plant with a capacity of 1000 m3/day, with a single stage and four membrane modules (FilmTec SW30HR-380) per pressure vessel, operating at a feed pressure of 6.0 MPa and with an inlet feed velocity of 0.12 m/s, the water recovery rate is 33%, the energy consumption is 4.28 kWh/m3, and the specific water cost is 81.4 eurocent/m3. The water cost can be reduced to 66.7 eurocent/m3, for a two-st...

83 citations

Journal ArticleDOI
TL;DR: A sufficient chemical water purification treatment system should consist of ion exchange and reverse osmosis and attention has to be paid to the suitability of materials in contact with the water and of the chemicals used, for example regenerants or corrosion inhibitors.
Abstract: BACKGROUND The bacterial and chemical contamination of dialysate fluids are important problems in haemodialysis therapy and may be caused by the water used for dialysate preparation. METHODS We performed a survey of the microbiological and chemical quality of the water used in seven dialysis wards. Special attention was paid to the effects of each water treatment step, for example ion exchange, reverse osmosis and UV disinfection, on the number of bacteria (measured as colony forming units, CFU), the amount of endotoxin (endotoxin units, EU) and various chemical parameters, the main focus being on calcium, magnesium, sulphate, aluminium and heavy metals. RESULTS CFU values exceeding the European Pharmacopeia value, determined at an incubation temperature of 22 degrees C, were found in the samples of raw water (20.0%, n=25), after ion exchange (66.7%, n=12), after reverse osmosis (33.3%, n=18) and also in samples of the dialysis water taken at the inlets (12.5%, n=40) and outlets (50.0%, n=18) of the machines. Whereas all raw water samples from the wards showed high mean values for endotoxin (0.56-9.10 EU/ml) and the endotoxin levels were often enhanced after ion exchange (0.13- >9.49 EU/ml), treatment by reverse osmosis led to a satisfactory decrease in endotoxin in all samples (<0.03 EU/ml). Sufficient reductions in calcium, magnesium and sulphate could only be achieved by the combined application of ion exchange and reverse osmosis. Mercury contamination was observed in the samples after ion exchange at three treatment plants, this was possibly caused by polluted regenerants. Increased amounts of aluminium, copper and zinc were found in water samples from different sites in the treatment systems and were caused by materials in contact with the water. CONCLUSIONS A sufficient chemical water purification treatment system should consist of ion exchange and reverse osmosis. Attention has to be paid to the suitability of materials in contact with the water and of the chemicals used, for example regenerants or corrosion inhibitors. From the microbiological point of view, a safety UV disinfection step in the water-treatment system is favourable. To avoid bacterial recontamination periodic cleaning and disinfecting of the water-treatment and distribution systems, as well as the dialysis machine are essential. There is the need for complete guidelines regarding dialysis water that include all relevant chemical and microbiological parameters. Based on this standard, periodic examination of the water after each treatment step has to be performed.

83 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe pilot test results obtained on Mediterranean seawater using a 0.1 μm hollow fiber Microza ® module and show that seawater silt density index (SDI) ranged between 6 to non-measurable.

83 citations

Journal ArticleDOI
TL;DR: In this article, the influence of biofouling on the performance of thin film composite NF and RO membranes was examined, and it was shown that biofilm growth on the membranes increased the hydraulic resistance to permeate flow due to bacterial extracellular polymeric substances (EPS).

83 citations

Journal ArticleDOI
TL;DR: Among liquid biofuels, biodiesel has the best energy yield, such that the amount of net biodiesel energy production is more than three times than that of diesel fuel.
Abstract: Global warming induced by greenhouse gases is major issue worldwide. There is therefore a need to develop renewable sources of energy, such as biofuels. Here, we review the various types of biofuels such as biodiesel, bioethanol, biomethane, hydrotreated vegetable oils and fats, and lignocellulosic-based fuels. First, second, and third generations of biofuels are compared in terms of economics, environmental aspects and energy yield. Economically, raw materials account for 60–75% of the final price of produced biofuels. The high cost of biodiesel compared to the lower price of diesel fuel is a major challenge toward commercializing biodiesel production from vegetable oils. Environmentally, biofuels can reduce carbon emissions and are more biodegradable compared to fossil fuels. For instance, biodiesel and diesel fuels are degraded by 95% and 40%, respectively, during one month in water. Among liquid biofuels, biodiesel has the best energy yield, such that the amount of net biodiesel energy production is more than three times than that of diesel fuel. We also review membrane technologies for the purification and separation of biofuels such as bioethanol, biobutanol, biodiesel, and biogas. Commonly used membrane processes are ultrafiltration, microfiltration, nanofiltration, pervaporation, membrane distillation and reverse osmosis. Reverse osmosis is used for water treatment due to the very small pore size of membranes, which allow the water molecules to get through. Membrane bioreactors can be used for wastewater treatment with a combination of ultrafiltration and reverse osmosis. Ultrafiltration and nanofiltration membranes have applications in the production of biomass from olive mill wastewaters. Pervaporation and membrane distillation are efficient in the third generation of bioethanol production plants.

83 citations


Network Information
Related Topics (5)
Wastewater
92.5K papers, 1.2M citations
86% related
Sorption
45.8K papers, 1.3M citations
78% related
Adsorption
226.4K papers, 5.9M citations
78% related
Aqueous solution
189.5K papers, 3.4M citations
74% related
Photocatalysis
67K papers, 2.1M citations
74% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023553
20221,099
2021636
2020782
20191,087
20181,331