Showing papers on "Reverse osmosis published in 1991"

Method and system for producing sterile aqueous solutions

Abstract: A process is provided for purifying potable water to produce American Association for Advancement of Medical Instrumentation (AAMI) standard water for dialysis, United States Pharmacopeia Convention, Inc. USP XXII specifications water for injection or sterile water for injection. Potable water is passed through a plurality of treatment steps including a preliminary filtration step, a carbon adsorption module and a reverse osmosis module to produce water to the quality specified by AAMI for hemodialysis. An ion exchange filtration step is added to the steps stated above to produce USP XXII quality specifications for water for injection and a disposable sterilizing microfilter is further added to all the steps stated above to produce sterile water for injection. The process is designed such that the system is sanitized with hot water and subsequently flushed at a temperature and time that will control microbial population as specified by the user requirements without degrading the materials of construction in the treatment steps, for example at 80° C. for one hour. The sterile microfilter used for the production of sterile water is a disposable device changed periodically to maintain sterility of the final solution.

Reverse osmosis system

Abstract: A reverse osmosis system includes a sediment filter which cleans feed water from a source and from which that feed water is fed to a reverse osmosis membrane filter. Permeate from the latter is fed to a bladder within a storage tank. Concentrate from the membrane filter is fed to and used within the storage tank as squeeze water for the bladder. When a faucet that delivers permeate to the user is open, squeeze water is used to cause permeate to flow out of the storage tank through an impurity filter to supply the faucet. A valve unit is included to control the amount of squeeze water fed to the storage tank and to regulate permeate flow so that the water outletted from the faucet remains at a constant pressure and provides relief as against overpressure in the system. A proportioning valve within the valve unit serves to maintain at all times a constant ratio of concentrate to permeate flow through the membrane filter for adequate cleansing of the membrane. Also included are input-side and output-side flow monitors which provide signals to a processor that serves to indicate the status of filter conditions. There also is an advantageous faucet assembly for controlling the delivery of permeate to the user with flexibility and convenience.

Method and apparatus for processing liquid solutions of suspensions particularly useful in the desalination of saline water

Abstract: A method and apparatus for reducing the concentration of a first substance in a first liquid by: (a) subjecting the first liquid to natural osmosis, via a first semipermeable body, with respect to an intermediate liquid, which intermediate liquid is a solution or suspension of a second substance in a second liquid, the second liquid being the same as the first liquid and passing through the first semipermeable body, the second substance being of larger molecular size than the first substance and not passing through the first semipermeable body, whereby the quantity of the second liquid in the intermediate liquid is increased; and then (b) subjecting the intermediate liquid to reverse osmosis under pressure via a second semipermeable body to pass therethrough the second liquid

Permeation equations developed for prediction of membrane performance in pervaporation, vapor permeation and reverse osmosis based on the solution-diffusion model

Abstract: General permeation equations based on the solution-diffusion model were proposed for pervaporation (PV), vapor permeation (VP) and reverse osmosis (RO) on two different assumptions about the pressure gradient inside a membrane: a flat gradient (case 1) and a linear gradient (case 2). With these equations the permeation properties in PV, RO and VP can be estimated once the transport parameter of a membrane is known.The effect of upstream pressure on selectivity and flux in RO and PV was estimated by sample calculations for water- and ethanol-selective membranes in ethanol–water system. Flux and selectivity in RO is smaller and, reaching that in PV at infinite pressure. This ultimate value is different in cases 1 and 2, and in the latter the molar volume ratio of the permeants becomes important. The effect of downstream pressure in PV was also estimated and compared with the case of vacuum-enhanced membrane distillation (MD) with a porous membrane. With increasing pressure the separation factor approaches that of vapor–liquid equilibrium in both PV and MD. With decreasing pressure that in MD is governed by the ratio of diffusion coefficients inside the membrane. Since the Knudsen diffusion coefficient of water is larger than that of ethanol, the separation factor decreases in ethanol–water separation with decreasing downstream pressure. This was verified by experiment, using PTFE membranes.

Method and apparatus having reverse osmosis membrane for concentrating solution

Abstract: A method and an apparatus for treating salt water by a multiplicity of reverse osmosis membrane modules or a structure constituted by combining a multiplicity of reverse osmosis membrane modules and an evaporating device and thereby capable of efficiently treating it while preventing excessively large energy consumption. Salt water is passed through a plurality of reverse osmosis membrane modules so as to be separated into desalted water of a potable water level and high density concentrated water the salinity quality of which is 80,000 to 120,000 ppm.

Liquid purifying system

Abstract: In a system for purifying liquid, a method is provided wherein the liquid is pretreated by passing it through a sand filter water softener and carbon filter for removal of hardness and particulate matter. The liquid is then pumped through a reverse osmosis membrane for removal of organic compounds and ionized and biological impurities. The liquid passes from the reverse osmosis membrane through a strong acid cation exchange resin for removal of the cations present in the reverse osmosis effluent. The acidified liquid is neutralized hy passing it through calcium carbonate, thus adding calcium salt and carbonic acid to the liquid for a better tasting, calcium-enriched product.

Method and apparatus for recycling R/O waste water

Abstract: Waste water discharged from a reverse osmosis unit served by a water feed line and producing potable water is returned to the water feed line for water conservation purposes. After periodic flushing of the reverse osmosis unit, the flush water may be returned to the water feed line or channelled to a drain. After each cycle of operation, any pressure differential between the water inflowing to and water outflowing from the reverse osmosis unit is relieved.

Refrigerator with purified water supply

Abstract: A refrigerator is combined with a reverse osmosis water purification system so that purified water is available at an ice-maker and water tap forming part of the refrigerator. The water is also chlorinated upstream of the reverse osmosis filter and dechlorinated downstream thereof, before the water is supplied to a tank. Level and purity sensors are provided in the tank for cutting off the supply of water when the tank is full and for indicating the purified condition of the water.

Composite reverse osmosis membrane and production thereof

Abstract: A composite reverse osmosis membrane composed of a microporous support layer and a thin layer supported thereon, characterized in that the thin layer is made of a crosslinked polyamide which comprises a polyamine component having two or more amino groups in the molecule and an acid component containing a linear aliphatic polyacid halide having two or more halogenated carbonyl groups in the molecule.

Compact reverse osmosis system with cold water flush

Abstract: A reverse osmosis purification system is operated on a ratio of approximately 1 to 1 to 2 to 1 waste water to product water. The system uses the cold water outlet and a cold water path which extends through the RO membrane to remove non-migrating particles trapped on the outside of the reverse osmosis membrane to remove salts from the membrane and allow to prolong the life of the membrane despite low brine to pure water ratio.

Reverse osmosis water purifier booster pump system

Abstract: A reverse osmosis water purification system that incorporates a high torque low speed motor to drive a pump, such that the pump can continuously pump water from a source of water to an osmotic membrane. The system may have a reservoir to store the purified water as it is pumped through the osmotic filter. The system can also have a transformer and rectifier to convert and rectify an alternating electrical power source to 24 volt DC power for the motor. The transformer having a higher impedance than the motor such that the transformer acts as a current limiter in the event the motor stalls. The pump has an internal pressure relief valve operatively connected to the inlet of the pump housing. The relief valve opens when the output pressure of the diaphragm piston reaches a predetermined valve. The relief valve allows the high pressure water to flow back into the housing inlet creating a flow loop from the inlet back to the water source.

Multilayer reverse osmosis membrane of polyamide-urea

Abstract: The present invention is directed to an improved reverse osmosis membrane that shows surprisingly improved solute rejection and permeation properties. The membrane includes a separating layer of a polyamideurea formed in situ by reaction of isocyanate-substituted acyl chloride and a diamine-treated microporous substrate.

Biofouling of Reverse Osmosis Membranes

Abstract: Reverse osmosis (RO) membranes used for the treatment of industrial and municipal process waters often become biologically fouled. The development of a microbial biofilm on the feedwater surfaces of RO membranes results in several adverse effects, including: (i) a gradual decline in the membrane water flux, (ii) an increase in the transmembrane operating pressure [i.e. an increase in the membrane delta-p], and (iii) a reduction in membrane mineral rejection. The RO membrane polymer itself may also be directly or indirectly biodegraded by the adherent microorganisms. Bacterial colonization of the permeate [i.e. product-water] surfaces of RO membranes can also occur. Although the extent of biofilm formation on the permeate surface is typically quite low compared to that on the feedwater surface, it can result in microbial contamination of downstream processes, which may be of great concern in ultra-pure water applications.

Asymmetric polyimide membranes

Abstract: An asymmetric membrane and a method for its preparation is disclosed. The membrane is suitable for gas separation, reverse osmosis and pervaporation applications and is characterized in that it is based on a fully imidized 5(6)-amino-1-(4'-aminophenyl)-1,3-trimethylindane polymer having pore diameters of less than 20 Å units, CO 2 /CH 4 selectivity of at least 20 and CO 2 permeability of at least 1.0 SCFH/ft 2 at 100 p.s.i.

Reverse osmosis or nanofiltration membrane and its production process

Abstract: The invention relates to a reverse osmosis or nanofiltration membrane and to its production process. This membrane comprises a porous support made from an inorganic material coated on one face with a first mesoporous inorganic material layer, e.g. of TiO2, having a mean pore radius below 10 nm and a second active layer, having a thickness of 0.1 to 1 μm, made from sulphonated polysulphone, polybenzimidazolone, grafted polyvinylidine fluoride or Nafion.®

Ocean depth reverse osmosis fresh water factory

Abstract: A process for the desalination of sea water by lowering from a floating platform (11) sets of vessels (66), which are constructed or laminated in part with reverse osmosis elements (65) or (64), into the ocean depth to extract fresh water. Thereafter, the fresh water filled vessel (66) is to be lifted individually from the ocean depth by means of a mechanical lifting system (33) to a predetermined elevation above the sea surface to facilitate the delivery of the extracted fresh water to a coastal water transportation system via a valve (44) at the bottom of the vessel (66) which is also connected to a water delivery pipeline (55).

Nitrate treatment methods: an overview

Abstract: Conventional water-treatment methods such as lime and soda-ash softening, filtration, and cation-exchange softening have no measurable effects on reducing nitrate concentrations in water supplies. There are, however, several methods that can be used to reduce nitrate concentrations in potable water supplies with varying degrees of efficiency. These methods include chemical precipitation, distillation, reverse osmosis, electrodialysis, ion-exchange, and biodenitrification. This paper reviews the progress of nitrate treatment processes with particular emphasis on ion exchange and biodenitrification. These two methods have been used extensively in the United States and Europe.

Treatment of lower glycol-containing operative fluids

Abstract: Operative fluids containing lower glycol are contacted with semi-permeable membranes under reverse osmosis conditions to permeate lower glycol to provide a reclaimed lower glycol product. Exemplary operative fluids include antifreeze solutions, heat transfer fluids, deicers, quenchants, hydraulic fluids, lubricants, solvents and absorbents.

The Major Developments of the Evolving Reverse Osmosis Membranes and Ultrafiltration Membranes

Abstract: The current status of reverse osmosis and ultrafiltration membranes are reviewed with the view for the future. In the case of reverse osmosis (RO) membranes, as examples, new crosslinked aromatic polyamide membranes exhibited the superior separation performance with the sufficient water permeability, the high tolerance for oxidizing agents and chemicals. Ultrafiltration (UF) membrane based on poly(phenylene sulfide sulfone)(PPSS) also exibited the superior separation performance with the high solvent, heat and fouling resistance.

Car wash system using reverse osmosis concentrate for initial rinsing and permeate for final rinsing

Abstract: A rollover type car wash and rinse machine which uses permeate from a reverse osmosis unit for a final rinse operation. The machine is operator controlled to wash and initially rinse cars with a spray arch using raw water and concentrate from the reverse osmosis unit. A final rinse can then be performed with a second spray arch using permeate alone, and only after a wash and initial rinse has been performed.

Chlorine-tolerant, thin-film composite membrane

Abstract: A semipermeable membrane suitable for reverse osmosis applications is prepared by interfacially reacting on a support an aromatic polyamine containing at least three and, preferably, four aromatic nuclei with a polyfunctional amine-reactive compound such as an aromatic polyacyl halide.

Desalination of brackish water from oil wells

Abstract: Non-brackish water can be produced from the brackish water found in many inactive oil wells. The inactive well is perforated at the level known to have brackish water and the water is pumped out. The brackish water is desalinated producing non-brackish water, preferably, potable water. A preferred method of desalination is by reverse osmosis.