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Showing papers on "Reverse osmosis published in 1986"


Journal ArticleDOI
TL;DR: The physicochemical treatment processes typically used to remove the more common inorganic contaminants from water and wastewater are described in this article, including coprecipitation, adsorption, ion exchange, membrane separations by reverse osmosis and electrodialysis.
Abstract: This article describes the physicochemical treatment processes typically used to remove the more common inorganic contaminants from water and wastewater. These are precipitation, coprecipitation, adsorption, ion exchange, membrane separations by reverse osmosis and electrodialysis, and combinations of these processes. The general criteria for process selection are discussed, and the processes and their typical applications are described.

152 citations


Journal ArticleDOI
TL;DR: In this article, a model of the fouling of reverse osmosis membranes by colloidal material has been developed for laminar flow and compared with the experimental results of colloidal ferric hydroxide.

146 citations


Patent
30 Jul 1986
Abstract: A semipermeable composite membrane comprising a microporous substrate and an ultra-thin membrane with which the substrate is coated, characterized in that the ultra-thin membrane is composed of a cross-linked aromatic polyamide and the cross-linked aromatic polyamide contains a tri- or higher functional aryl residue having at least two --NH groups. The semipermeable composite membrane has a high solute rejection, high and stable water flux and durability, and thereby may be applicable to various fields.

98 citations


Book ChapterDOI
01 Jan 1986
TL;DR: In this paper, the different membrane structures, their function and application in various separation processes are described, and the preparation procedures of the various membrane types are discussed with special emphasis on symmetric and asymmetric membranes obtained by the phase inversion process.
Abstract: In recent years, separations with synthetic membranes have become increasingly important processes in the chemical industry, in food and wastewater processing, and in medical treatment. Synthetic membranes made from a variety of polymers are used in processes such as microfiltration, ultrafiltration, reverse osmosis, electrodialysis, and gas separations. In this paper, the different membrane structures, their function and application in various separation processes are described. The preparation procedures of the various membrane types are discussed with special emphasis on symmetric and asymmetric membranes obtained by the phase inversion process.

80 citations


Journal ArticleDOI
TL;DR: In this paper, the problem of dilute solvent concentration in butanol-acetone fermentations can be solved by using reverse osmosis to dewater the fermentation liquor, and polyamide membranes have a potential application in a butanolacetone fermentation and exhibited rejection rates as high as 98%.
Abstract: The problem of dilute solvent concentration in butanol-acetone fermentations can be solved by using reverse osmosis to dewater the fermentation liquor. Polyamide membranes have a potential application in a butanol-acetone fermentation and exhibited rejection rates as high as 98%. Optimum rejection of butanol in the fermentation liquor occurred at recoveries of 20-45%. Flux ranged from 0.05 to 0.6 L m(-2) min(-1).

78 citations


Patent
28 Apr 1986
TL;DR: A water softening membrane and process for making the same is described in this paper, which can be prepared by treating a polyamide reverse osmosis membrane with a strong mineral acid followed by treatment with a rejection enhancing agent.
Abstract: A novel water softening membrane and process for making the same is described. The membrane can be prepared by treating a polyamide reverse osmosis membrane with a strong mineral acid followed by treatment with a rejection enhancing agent. The resulting membrane at transmembrane pressures of 50 psi can attain a magnesium sulfate rejection with a 0.2 percent aqueous solution of more than 90 percent with a water flux of more than 15 gallons per square foot per day.

77 citations


Patent
18 Aug 1986
TL;DR: Semipermeable membranes of a porous polymeric substrate whose external and all internal surfaces (pores) are encapsulated by a semi-meable thin film of a hydrophilic polymer are provided in this paper.
Abstract: Semipermeable membranes of a porous polymeric substrate whose external and all internal surfaces (pores) are encapsulated by a semipermeable thin film of a hydrophilic polymer are provided. The encapsulating film consists of at least one layer of said polymer which is cross-linked/stabilized by polyfunctional compounds containing at least two functional (reactive) groups. The membrane substrate is optionally pretreated--before the encapsulation step--with polyfunctional compounds. The new membranes can be used in ultrafiltration and reverse osmosis processes. They are solvent-, pressure- and temperature-resistant and show good separation capacities, e.g. for separating organic compounds from salt solutions.

64 citations



Journal ArticleDOI
TL;DR: In this paper, a reverse osmosis (RO) water treatment plant equipped with conventional cellulose acetate membranes, and two pilot RO plants, equipped with polyamide membranes, were tested for their ability to remove total organic carbon and a broad range of trace organics, including volatiles, purgeables, neutrals, bases, phenols, and acids from lime-clarified secondary municipal wastewater.
Abstract: A full-scale (8-cfs [0.22-m3/s]) reverse osmosis (RO) water treatment plant equipped with conventional cellulose acetate membranes, and two pilot RO plants, equipped with polyamide membranes, were tested for their ability to remove total organic carbon and a broad range of trace organics, including volatiles, purgeables, neutrals, bases, phenols, and acids from lime-clarified secondary municipal wastewater. The full-scale RO system removed total organic carbon (TOC) by 89 percent to 0.95 mg/L at 84-percent water recovery, and the pilot RO systems removed TOC by 99 percent to 0. 1 mg/L at water recoveries of 52 and 67 percent, respectively. The two membranes tested showed significant differences in their ability to reject trace organics. All membranes rejected branched, complex molecules but varied in their rejection characteristics for smaller molecules, such as chlorinated solvents. The latter group was rejected to a varying degree by polyamide membranes but passed through cellulose acetate membranes. The use of RO for trace organics removal is evaluated by comparing cumulative removals of different treatment schemes with and without RO treatment.

53 citations


Patent
10 Feb 1986
TL;DR: A reverse osmosis water purification system for purification of water received from a supply tank having a limited and exhaustible supply of water is presented in this article, where water is extracted from the supply tank by a pump which directs the extracted water under pressure to a reverse Osmosis unit.
Abstract: A reverse osmosis water purification system for purification of water received from a supply tank having a limited and exhaustible supply of water Water is extracted from the supply tank by a pump which directs the extracted water under pressure to a reverse osmosis unit which in turn directs the purified water to a hydro-pneumatic storage tank with the waste water produced by the reverse osmosis unit being returned to the supply tank for water conservation purposes The system further includes a pressure sensing switch associated with the hydro-pneumatic storage tank and the pump to maintain the differential pressure across the reverse osmosis unit in a predetermined pressure range

48 citations


Journal Article
TL;DR: Two reverse osmosis systems were employed for the production of low alcohol content wine without having to add water and the product intended for manufacture by the proposed technique remains `wine9 by its composition and organoleptic quality.
Abstract: The possibilities of using the reverse osmosis process for the production of low alcohol content wine without having to add water are described. Two reverse osmosis systems were employed. The first was equipped with ethanol-permeable membranes and the second with selective ethanol-retention membranes. The permeate-exchange unit ensures the water and ethanol balance of the system. The product intended for manufacture by the proposed technique remains `wine9 by its composition and organoleptic quality.

Patent
21 Mar 1986
TL;DR: An apparatus for purifying drinking water by a combination of reverses osmosis, deionization by ion exchange resins, resin and final passage through activated carbon is described in this article.
Abstract: An apparatus for purifying drinking water by a combination of reverses osmosis, deionization by ion exchange resins, resin and final passage through activated carbon. The components for reverse osmosis, de-ionization, and passage through active carbon, and a product water reservoir are housed in a cabinet suitable for placement in a home. Ionic impurities are removed by reverse osmosis through a cellulose acetate membrane which feeds the flux water to a mixed resin bed for deionization. Waste brine is removed from the reverse osmosis module by controlled leakage to maintain concentration at a low level. The product water is filtered through a cartridge of granular activated carbon prior to being stored in a product water reservoir. An attachment is connectable with the tap water faucet to provide tap water to the unit at main water supply pressure and to dispose of waste brine water and excess product water. Components are replaceable and available on the market.

Book ChapterDOI
01 Jan 1986
TL;DR: The film-forming ability of chitosan has been the object of many studies, some of which have led to industrial uses in various fields such as photographic films, reverse osmosis membranes and cosmetics.
Abstract: The film-forming ability of chitosan has been the object of many studies, some of which have led to industrial uses in various fields. Photographic films, reverse osmosis membranes and cosmetics containing significant amounts of chitosan are now being marketed.

Book
01 Jan 1986
TL;DR: An extensive review of the literature was conducted and results were evaluated for the use of the reverse osmosis process in the treatment of drinking water supplies as mentioned in this paper, including pretreatment requirements, membrane type and configuration, membrane cleaning and maintenance, and reverse Osmosis removal of organics, inorganics, and microbial contaminants.
Abstract: An extensive review of the literature was conducted and results were evaluated for the use of the, reverse osmosis process in the treatment of drinking water supplies. All aspects of reverse osmosis technology, including pretreatment requirements; membrane type and configuration; membrane cleaning and maintenance; and reverse osmosis removal of organics, inorganics, and microbial contaminants were incorporated into the literature evaluation. A survey (Appendix E) of existing full scale reverse osmosis installations was also carried out and results of the survey are discussed. In light of data presented in the literature and results of the survey conducted, the following recommendations were made to prevent catastrophic membrane fouling occurrences and costly plant shutdowns in the future. 1) Conduct a comprehensive raw water quality evaluation. 2) M,aintain cont inuous feed and product water qual ity monitoring. 3) Incororate process automation and system upset warning provisions in future installations. 4) Provide greatly improved training for reverse osmosis installation operators. The reverse osmosis system is particularly well suited for the treatment of water supplies which contain a number of contaminants that would otherwise require a combination of treatment processes for their removal, due to the ability of the reverse osmosis process to remove salts, organics, and a number of microbial contaminants. Effective pretreatment and routine backwashing, membrane cleaning, and disinfecLion must be carried out; however, if adequate system operation is to be assured.

Journal ArticleDOI
TL;DR: In this paper, the authors summarized recent trends in ion exchange membrane research from viewpoint of manufacturing ion exchange membranes and discussed industrial applications of the membranes, being practiced, are discussed according to their experience.
Abstract: Recent trends in ion exchange membrane research are summarized from viewpoint of manufacturing ion-exchange membranes. While ion-exchange membranes used in industrial area are mostly of the polymerization types crosslinked by divinylbenzene or of perfluorocarbon types, various attempts to make new types of membranes have also been made using other polymers and different methods. For certain industrial requirements, ion-exchange membranes having an anisotropic structure are used in various areas : electrodialytic concentration of sea water, electrolysis of sodium chloride, reverse osmosis etc. And micro—structure of the membranes is also actively analyzed by various measuring methods. Industrial applications of the membranes, being practiced, are discussed according to our experience. Electrodialysis is applied to concentration of sea water for making edible salt, demineralization of saline water, treatment of waste water and food industry. Electrolysis of sodium chloride and other solutions is also discussed. Other applications are diffusion dialysis to recover acid from waste acid solutions, and separator for battery. In this work, other various researches concerning membrane usage are explained by citing the literature.

Journal ArticleDOI
TL;DR: The review is not exhaustive, but rather it focuses on four processes that appear to offer the greatest potential for general application in the water supply and wastewater treatment industries.
Abstract: The review is not exhaustive, but rather it focuses on four processes that appear to offer the greatest potential for general application in the water supply and wastewater treatment industries. These processes are chemical oxidation, a transformation process; air stripping, a liquid-gas separation process; two variants of a liquid-solid separation process, carbon adsorption and ion exchange adsorption; and two membrane separation processes, reverse osmosis and ultrafiltration. Figures 1 and 2 illustrate typical applications of these processes for water supply and wastewater treatment (4,5). The discussion of each process is complemented by a diagram and an example of typical application. Associated design considerations and features are presented in sidebars, each of which presents a set of equations that comprise a mathematical description, or model, of the process in question. 59 references, 6 figures.

Journal ArticleDOI
TL;DR: In this paper, the authors discuss the constraints of reverse osmosis desalination and the techniques and controls generally recommended in the design and operation of reverse Osmosis systems.

Patent
24 Nov 1986
TL;DR: In this paper, a method for concentrating alcoholic beverages which comprises subjecting the beverage to reverse osmosis to form a beverage concentrate, using a membrane which allows passage of water therethrough and is at least partially permeable to alcohol and volatile flavor components of the beverage but is impermeable to dissolved solids.
Abstract: A method for concentrating alcoholic beverages which comprises subjecting the beverage to reverse osmosis to form a beverage concentrate, said reverse osmosis using a membrane which allows passage of water therethrough and is at least partially permeable to alcohol and volatile flavor components of the beverage but is impermeable to dissolved solids, subjecting the permeate from said reverse osmosis to distillation to separate therefrom alcohol and volatile flavor components of the beverage which have passed through the membrane, and combining the separate alcohol and volatile components with beverage concentrate from reverse osmosis. Apparatus for effecting this method is also described.

Journal ArticleDOI
TL;DR: In this paper, a reverse osmosis hollow-fibre membranes have been employed as a means of generating supersaturation in a plug flow system and precipitating calcium oxalate.

Patent
27 May 1986
TL;DR: A post-mix soft drink dispenser includes, in the feed water supply, a reverse osmosis unit for treating the inlet water and a carbonator for adding carbon dioxide to the treated water as discussed by the authors.
Abstract: A post-mix soft drink dispenser includes, in the feed water supply, a reverse osmosis unit for treating the inlet water and a carbonator for adding carbon dioxide to the treated water. The use of RO water provides a better tasting soft drink, allows the use of substantially less soft drink syrup or a combination thereof. An ingredient water tap downstream of the reverse osmosis unit allows the use of RO water in recipes, particularly for baked products, providing surprising results.

Patent
24 Jun 1986
TL;DR: In this paper, a composite lumen-side feed reverse osmosis membrane and its preparation are disclosed, the membrane comprising a polymeric microporous-walled hollow fiber support with an interfacially-polymerized ultrathin semipermeable salt-rejecting layer engrafted on the lumen or bore of the hollow fiber.
Abstract: A composite lumen-side feed reverse osmosis membrane and its preparation are disclosed, the membrane comprising a polymeric microporous-walled hollow fiber support with an interfacially-polymerized ultrathin semipermeable salt-rejecting layer engrafted on the lumen or bore of the hollow fiber support, the support having walls that are substantially completely free of finger-like voids in excess of about 5 microns in the area of the wall adjacent the lumen. The preparation of the support comprises coaxially spin-casting (1) a fiber-forming solution containing a pore-forming material with (2) a lumen-forming fluid comprising from about 50 to about 70 vol % organic solvent in water.

Journal ArticleDOI
TL;DR: In this paper, the composition and properties of distillate and permeates and the different remineralization and potabilization processes to make potable water and to avoid corrosion in the Potable Water system are discussed.

Patent
11 Jul 1986
TL;DR: In this article, a dynamic membrane is obtained by coating on a porous polymeric substrate containing functional groups a chemically reactive hydrophilic polymer from a dilute aqueous solution under pressure and crosslinking said polymer present on the porous substrate as thin layer with low molecular polyfunctional compounds.
Abstract: Dynamic membranes are obtained by coating on a porous polymeric substrate containing functional groups a chemically reactive hydrophilic polymer from a dilute aqueous solution under pressure and crosslinking said polymer present on the porous substrate as thin layer with low molecular polyfunctional compounds. The new membranes show good solvent and compaction resistance and resistance to separation of the individual layers. They can be used in ultrafiltration and reverse osmosis processes.

Patent
29 Sep 1986
TL;DR: In this article, an apparatus for the production of fresh water from seawater, intended to be immersed into the marine medium, is described, which consists of one high pressure chamber (1) containing a selective semi-permeable reverse osmosis membrane (11) and a bell chamber (14) having an internal axial piston permitting by a multiplier effect, to obtain at the interior of the chamber a pressure equal to the exterior pressure multiplied by a ratio S/s of the working surfaces of the bell chamber and the internal piston.
Abstract: The invention relates to an apparatus for the production of fresh water from seawater, intended to be immersed into the marine medium. The apparatus comprises one high pressure chamber (1) containing a selective semi-permeable reverse osmosis membrane (11) and a bell chamber (14) having an internal axial piston permitting by a multiplier effect, to obtain at the interior of the chamber (1) a pressure equal to the exterior pressure multiplied by a ratio S/s of the working surfaces of the bell chamber and the internal piston. The semi-permeable membrane communicates across a separation wall (3) of the high pressure chamber with the interior volume of the bell chamber (14). This internal volume is placed in communication with the surface by a flexible tube (25) in such a manner as to play the dual role of, on one hand, a subatmospheric gas chamber, and on the other hand means for receiving fresh water after osmosis across the membrane.

Patent
17 Jan 1986
TL;DR: In this paper, a reverse osmosis unit is provided having an unpurified water inlet, a reject water outlet and a product water outlet, which is connected to a water regulating means.
Abstract: A system is provided for supplying purified water, without requiring continuous flow of water across the water purification device. A reverse osmosis unit is provided having an unpurified water inlet, a reject water outlet and a product water outlet. The unpurified water inlet is connected to a source of unpurified water. The reject water outlet and the product water outlet are connected to water regulating means. The water regulating means has outlets to drain and to an accumulator tank. When pressure in the accumulator tank is below a predetermined amount, a diaphragm responsive to the pressure operates a pair of spool valves to first automatically direct a first amount of product water only to drain. Thereafter, the spool valves automatically discontinue flow of the first amount of product water to drain and direct the product water to the accumulator tank. In this manner, the first amount of water which has been standing and was subject to osmosis and/or excessive bacteria multiplication does not enter the accumulator tank.

Journal ArticleDOI
TL;DR: In this paper, the authors discuss two very different membrane-based hybrid applications: the processing of corn steep water, and the recycle of space-station wash waters, and discuss the criteria used for the design of the membranebased hybrid processes for each application.

Patent
16 Oct 1986
TL;DR: In this article, a microporous hollow support fiber is passed through a solution of a monomer capable of undergoing condensation polymerization and such as m-phenylene diamine up through a capillary into a sedond less dense solution of another monomer, such as trimesoyl chloride or cyclohexane-1,3,5-tricarbonyl chloride.
Abstract: A process for preparing reverse osmosis membranes is disclosed. A microporous hollow support fiber is passed through a solution of a monomer capable of undergoing condensation polymerization and such as m-phenylene diamine up through a capillary into a sedond less dense solution of a second monomer capable of undergoing condensation with said first monomer, such as trimesoyl chloride or cyclohexane-1,3,5-tricarbonyl chloride. The resulting fiber has a polymeric film deposited thereon which is effective as a reverse osmosis membrane.


Patent
12 Mar 1986
TL;DR: In this paper, a deoxidizing agent is injected in treated water and degassing is performed to prevent the embrittlement and destruction of a reverse osmosis membrane element.
Abstract: PURPOSE:To perfectly remove the salt contained in sea sand for reinforced concrete, by a method wherein washing water is sprinkled over the sea sand during the transfer on a belt conveyor while the used washing water is degassed after filtering and receives the injection of a deoxigenating agent and desalting treatment according to a reverse osmosis method before repeated use. CONSTITUTION:Sea sand 3 collected by seawater is transferred by a washing belt conveyor 4 and washing water is sprinkled over sea sand 3 from the nozzles 5A of a water sprinkling head 5 to wash off the salt contained in sea sand 3 while washed sand is drained to be stored in a sand collection tank 9 and utilized as sand for concrete. Waste washing water is passed through a filter tank 11 from a water collection tank 10 to remove fine particulate sand and dust therein by filtering and a deoxidizing agent 12A is injected in the filtered water to remove dissolved oxygen to send said water to a degassing device 12 where oxygen and carbon dioxide dissolved therein are degassed under a vacuum degassing condition. A deoxidizing agent 12B is again injected in treated water and degassing is perfectly performed to prevent the embrittlement and destruction of a reverse osmosis membrane element. Subsequently, the treated water is sent to a reverse osmosis apparatus 15 under pressure by a high pressure water feed pump 7A to remove salts and purified water 19 is sent to a water storage tank 1 to be again used as washing water.

Patent
13 Jun 1986
TL;DR: In this article, a reverse osmosis treatment was used to obtain highly desalted water containing no scale and sludge, where an acid was injected in raw water in order to prevent scaling and the pH of raw water at the inlet of the reverse Osmosis apparatus was adjusted to weak acidity.
Abstract: PURPOSE: To obtain highly desalted water containing no scale and sludge, by performing desalting by reverse osmosis treatment in a first stage wherein an acid is added to water to remove the divalent ion therein and a second stage wherein an alkali agent is added to water to remove silica. CONSTITUTION: Raw water 1 containing silica at high concn. is pressurized by a pressure pump 5 to raise the pressure thereof to reverse osmosis pressure and sent to a reverse osmosis apparatus 6 to be subjected to first stage reverse osmosis treatment. At this time, an acid is injected in raw water in order to prevent scaling and the pH of raw water at the inlet of the reverse osmosis apparatus 6 is adjusted to weak acidity. The transmitted water 9 from which the hardness components in water such as calcium and magnesium are removed at a high ratio in the first stage is contacted with air in a decarbonator 10 to remove carbon dioxide. An alkali agent is added to the treated water after degassing from a storage tank 10 to raise the pH of the treated water to make it possible to raise silica solubility to a large extent and silica is removed in the reverse osmosis apparatus 19 at a second stage. COPYRIGHT: (C)1987,JPO&Japio