Showing papers on "Reverse osmosis published in 2004"
TL;DR: In this paper, the application of both reverse osmosis (RO) and nanofiltration (NF) technologies for the treatment of wastewater containing copper and cadmium ions to reduce fresh water consumption and environmental degradation was investigated Synthetic wastewater samples containing Cu2+ and Cd2+ ions at various concentrations were prepared and subjected to treatment by RO and NF in the laboratory.
497 citations
TL;DR: A review of the use of membrane processes for concentrated fruit juice processing can be found in this paper, where major attentions are focused on the application of new membrane processes and integrated membrane systems.
474 citations
TL;DR: In this article, the authors revisited the formulation of the theory for pressure-driven processes where both solute and solvent transports occur exclusively by the solution-diffusion mechanism, and the results showed that the flux of solvent must reach a finite value as the pressure differential becomes very large.
403 citations
TL;DR: In this paper, the performance of three hydrophobic microporous membranes were evaluated under vacuum enhanced direct contact membrane distillation (DCMD) with a turbulent flow regime and with a feed water temperature of only 40°C.
385 citations
TL;DR: In this article, an experimental study on the reverse osmosis desalination of aqueous solutions using α-alumina-supported MFI-type zeolite membranes was conducted.
236 citations
TL;DR: A systematic investigation on the influence of colloidal fouling on removal of trace organics (steroid hormones) and inert organics by reverse osmosis (RO) membranes is reported in this article.
220 citations
TL;DR: In this paper, the authors presented new products with higher flow (7500-9000 gpd at standard test conditions) and high rejection (99.70-99.75%) for the seawater desalination segment.
177 citations
TL;DR: In this paper, the effect of varying the Na 2 SO 4 salt and methyl orange (MO) dye concentrations on the performance of a spiral wound polyamide membrane was studied and a theoretical model based on the solution diffusion (SD) mass transport theory was developed to take into account a pressure dependent dynamic membrane resistance as well as both salt and dye concentration polarizations.
Abstract: The efficiency of reverse osmosis (RO) membranes used for treatment of colored water effluents can be affected by the presence of both salt and dyes. Concentration polarization of each of the dye and the salt and the possibility of a dynamic membrane formed by the concentrated dye can affect the performance of the RO membrane. The objective of the current work was to study the effect of varying the Na 2 SO 4 salt and methyl orange (MO) dye concentrations on the performance of a spiral wound polyamide membrane. The work also involved the development of a theoretical model based on the solution diffusion (SD) mass transport theory that takes into consideration a pressure dependent dynamic membrane resistance as well as both salt and dye concentration polarizations. Control tests were performed using distilled water, dye/water and salt/water feeds to determine the parameters for the model. The experimental results showed that increasing the dye concentration from 500 to 1000 ppm resulted in a decrease in the salt rejection at all of the operating pressures and for both feed salt concentrations of 5000 and 10,000 ppm. Increasing the salt concentration from 5000 to 10,000 ppm resulted in a slight decrease in the percent dye removal. The model’s results agreed well with these general trends.
176 citations
TL;DR: In this paper, a wide variety of cleaning agents including acids, bases, enzymes and complexing agents were used for the cleaning of reverse osmosis (RO) membranes fouled by whey and the effect of operating conditions such as transmembrane pressure, temperature and cross-flow velocity on flux behavior were elucidated before studying the cleaning.
153 citations
TL;DR: In this article, the design of a stand-alone hybrid wind-PV system to power a seawater reverse osmosis desalination unit, with energy recovery using a simplified spreadsheet model, was presented.
138 citations
TL;DR: In this paper, the feasibility of brackish groundwater treatment by reverse osmosis (RO) for potable water production was investigated in Jordan, and the results showed that RO is actually efficient since it highly reduced the content of organic and inorganic matters present in raw waters (rejections >98.5%).
TL;DR: In this article, the authors used a membrane bioreactor in wastewater treatment to remove arsenic from the treated water and showed that the membrane in hybrid systems allows a better phase separation between the particles binding the arsenic and treated water.
Abstract: Arsenic contamination as a consequence of human activities such as mining and pesticide use is affecting the water resource quality worldwide. Because of the high risk of arsenic exposure, specific water treatment processes are required to meet the anticipated more severe water quality standards. Better understanding of presently available processes is necessary to develop economic, efficient and effective methods for arsenic removal. Arsenic could either be coagulated, adsorbed using a wide range of materials both mineral and organic or could be directly rejected by membrane processes such as reverse osmosis and nanofiltration. The recent development of submerged hybrid membrane systems, such as membrane bioreactor in wastewater treatment, offers alternative technologies for arsenic treatment. The membrane in hybrid systems allows a better phase separation between the particles binding the arsenic and the treated water. The effect of pH and contact time, and the existence of other ionic compounds must be taken into account when designing the system for optimum arsenic rejection. Further research on both hydraulic and removal performances of hybrid adsorption/membrane technology is still required to assess the full potential of this technology for arsenic removal.
TL;DR: In this article, the potential use of a nanofiltration membrane for rejection of heavy metal ions such as Ni2+ from wastewater from Ni-P electroless plating industry was studied.
TL;DR: In this paper, two membrane-based options for treating sewage for water reuse, tertiary filtration (TF) of the effluent from a conventional activated sludge (CAS) process and an integrated membrane bioreactor (MBR), were compared from technical, performance and cost points of view using ZeeWeed® immersed membranes.
TL;DR: Treatment to the level of ultrafiltration was more than adequate to produce a water quality meeting existing worldwide reclaimed water guidelines for toilet flushing, and no significant microbiological growth was observed in the reclaimed water distribution system during the year.
TL;DR: In this paper, the NTR 7410 ultrafiltration (UF) membrane was used without and with pretreatment to treat biologically treated sewage effluent (BTSE) to assess the suitability of the membranes, it is important to conduct a detailed membrane characterization.
TL;DR: In this paper, two open-access seawater pre-treatment upstream reverse osmosis desalination plants were investigated, one in the Gulf of Oman and the other in the Persian Gulf.
TL;DR: In this article, a pilot plant membrane system with a designed processing capacity of 1 m3/h, comprising of nano and reverse osmosis (RO) membrane units, accompanied by several pre-treatment operations, was evaluated in order to further treat and reuse the tannery wastewater.
TL;DR: In this article, a numerical analysis tool for the estimation of boron reduction, in reverse osmosis (RO) desalination plants, was developed, which enables proper variations of some controllable parameters for significant permeate reduction.
TL;DR: An overview of the main membrane-assisted processes that can be used for the removal of toxic inorganic anions from drinking water supplies is provided in this article, with a focus on integrated process solutions, including the emerging issue of membrane bioreactors.
Abstract: This paper is designed to provide an overview of the main membrane-assisted processes that can be used for the removal of toxic inorganic anions from drinking water supplies. The emphasis has been placed on integrated process solutions, including the emerging issue of membrane bioreactors. An attempt is made to compare critically recently reported results, reveal the best existing membrane technologies and identify the most promising integrated membrane bio/processes currently being under investigation. Selected examples are discussed in each case with respect to their advantages and limitations compared to conventional methods for removal of anionic pollutants. The use of membranes is particularly attractive for separating ions between two liquid phases (purified and concentrated water streams) because many of the difficulties associated with precipitation, coagulation or adsorption and phase separation can be avoided. Therefore, membrane technologies are already successfully used on large-scale for removal of inorganic anions such as nitrate, fluoride, arsenic species, etc. The concentrated brine discharge and/or treatment, however, can be problematic in many cases. Membrane bioreactors allow for complete depollution but water quality, insufficiently stable process operation, and economical reasons still limit their wider application in drinking water treatment. The development of more efficient membranes, the design of cost-effective operating conditions, especially long-term operations without or with minimal membrane inorganic and/or biological fouling, and reduction of the specific energy consumption requirements are the major challenges.
TL;DR: In this paper, a factorial design was employed to integrate four independent factors, i.e., membrane type, dissolved organic carbon (DOC) composition, divalent cation and monovalent cation, to investigate their influences on specific flux decline and fouling.
TL;DR: In this paper, a complex membrane filtration technology for whey processing was developed, where hollow-fibre, ceramic, and spiral wound modules were used to extract the permeates from micro-and ultra-filtration (MF and UF).
TL;DR: In this article, the potential of a reverse osmosis (RO)membrane for defluoridation of underground water samples at different solute concentrations was studied and the results indicated that RO membranes can be successfully used for the treatment of underground waters to the desired purity level, as they remove up to 95% of fluoride present in water and also take care of other ions present in the water.
TL;DR: In this article, the reverse osmosis (RO) membrane separation of chromium from the pretreated solution was investigated in a pilot scale investigation, that proved its applicability for small and medium tanning workshops.
TL;DR: In this paper, the potential of two membrane processes for the production of concentrated camu-camu juice with high vitamin C content was evaluated in a pilot scale equipment, using a composite film membrane with 95% NaCl rejection.
TL;DR: In this paper, reverse osmosis was performed on an α-alumina-supported MFI-type zeolite membrane synthesized by in-situ crystallization, and the separation efficiency in terms of ion rejection was found to increase with the ion valence in the order rAl3+> rMg2+ > rNa+, while the ion and water fluxes changed in the reverse order.
TL;DR: In this article, three driving force membrane processes (RO-DS3SE, NF-DS5DK and UF-DSGM) were used for phthalate removal from water.
TL;DR: In this paper, a review of different nanofiltration membranes has been presented, with examples and compared with reverse osmosis membranes, and the capabilities of these membranes have been illustrated with examples.
Abstract: Membranes are widely used for separation of ions from a mixture in aqueous solution. Major applications include removal of sulfate from seawater, removal of salt from cheese whey, and separation of sodium chloride from seawater for manufacture of table salt and brine for soda industry. The conventional reverse osmosis membranes are not capable of selectively separating electrolytes from the aqueous mixture. The charged nanofiltration membranes that have been developed over the last decade are now being used for some of these applications. This review is based on the theories of transport of solute and water through these membranes and the mechanism of permselectivity. The application of these theories to estimate the membrane design parameters, i.e., pore size, porosity, charge density and thickness has been discussed. The capabilities of different nanofiltration membranes have been illustrated with examples and compared with reverse osmosis membranes. The information provided here is expected to provide an extensive information on the subject.
TL;DR: In this article, the performance of small scale UV/TiO 2 photocatalytic pilot plant process in treating secondary and tertiary treated effluent from a wastewater treatment plant in Bahrain was evaluated in terms of the efficiency of removing a chlorine resistant parasite, namely, Strongyloides Stercolaris, in addition to reducing the chemical oxygen demand (COD).
Abstract: Photocatalytic and membrane processes are strong candidates for improving conventional water treatment processes. These advanced treatment methods are capable of removing many pollutant chemicals as well as pathogenic microorganisms. The objective of this work was to study the performance of small scale UV/TiO 2 photocatalytic pilot plant process in treating secondary and tertiary treated effluent from a wastewater treatment plant in Bahrain. The performance was evaluated in terms of the efficiency of removing a chlorine resistant parasite, namely, Strongyloides Stercolaris , in addition to reducing the chemical oxygen demand (COD). The effect of pH and exposure time were considered. The performance of the UV/TiO 2 was compared with small pilot scale ultrafiltration (UF) and reverse osmosis (RO) membrane processes. Treatment of the samples with each of the UV/TiO 2 , UF and RO processes resulted in a complete removal of the S. stercolaris parasites. Moreover, the chemical oxygen demand was reduced by about 50, 64 and 86% with each of UV/TiO 2 , UF and RO. The specific power consumption of the UV/TiO 2 process was estimated to be about 4.0 kWh/m 3 for each of UV/TiO 2 and sea water RO (SWRO)and 1.0 kWh/m 3 and 0.9 kWh/m 3 for each of brakish water RO (BWRO) and cross flow UF, respectively. The UV/TiO 2 process produces no waste stream, whereas the RO and UF processes generate waste streams which are concentrated in the microorganisms and suspended organic matter, which result in a disposal problem.
TL;DR: In this article, the performance and fouling of nanofiltration (NF) and reverse osmosis (RO) membranes in the treatment of dairy industry wastewater were investigated and two series of experiments were performed.