EP0435944A1 - Procede de purification de l'eau - Google Patents

Procede de purification de l'eau

Info

Publication number
EP0435944A1
EP0435944A1 EP89911270A EP89911270A EP0435944A1 EP 0435944 A1 EP0435944 A1 EP 0435944A1 EP 89911270 A EP89911270 A EP 89911270A EP 89911270 A EP89911270 A EP 89911270A EP 0435944 A1 EP0435944 A1 EP 0435944A1
Authority
EP
European Patent Office
Prior art keywords
water
container
membrane
process according
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP89911270A
Other languages
German (de)
English (en)
Inventor
Michael Wilson
Philip 39 South View Road Monro
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hampshire Advisory and Technical Services Ltd
Original Assignee
Hampshire Advisory and Technical Services Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hampshire Advisory and Technical Services Ltd filed Critical Hampshire Advisory and Technical Services Ltd
Publication of EP0435944A1 publication Critical patent/EP0435944A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/002—Forward osmosis or direct osmosis
    • A—HUMAN NECESSITIES
    • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
    • A23C—DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; MAKING THEREOF
    • A23C9/00—Milk preparations; Milk powder or milk powder preparations
    • A23C9/15—Reconstituted or recombined milk products containing neither non-milk fat nor non-milk proteins
    • A23C9/1508—Dissolving or reconstituting milk powder; Reconstitution of milk concentrate with water; Standardisation of fat content of milk
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2/00—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor
    • A61L2/02—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor using physical phenomena
    • A61L2/022—Filtration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/445—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by forward osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/50—Treatment of water, waste water, or sewage by addition or application of a germicide or by oligodynamic treatment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/68—Treatment of water, waste water, or sewage by addition of specified substances, e.g. trace elements, for ameliorating potable water
    • C02F1/685—Devices for dosing the additives
    • C02F1/688—Devices in which the water progressively dissolves a solid compound

Definitions

  • This invention relates to the provision of water free of micro-organisms and the enterotoxins of Vibrio cholerae and Shigella species. It will be of particular use during periods of emergency due to natural disasters and in other situations where a microbiologically safe supply of water is not readily accessible.
  • the main water-borne bacterial pathogens are: Salmonella typhi , Salmonella paratyphi A, B and C, Entamoeba histolytica, Giardia lamblia, Vibrio cholerae, Shigella species, Campylobacter jejuni, Escherichia coli, Vibrio parahaemolyticus. Hepatitis. A virus, rotaviruses and Cryptosporidium and Schistosoma species. In addition, during periods of natural diaster, other infectious diseases can be transmitted via contaminated water. One of the main aims of water treatment processes is to remove such harmful organisms.
  • enterotoxins which are liberated from the .organism and may, by themselves, cause disease in the absence of the microbe.
  • enterotoxins include two of the most important water-borne pathogens. Vibrio cholerae and Shigella species, the causative agents of cholera and bacillary dysentery. The molecular weights of these enterotoxins are 90 kiloDaltons and 82 kiloDaltons respectively. An ideal water-purifying system would therefore also have to ensure that these enterotoxins were removed as well as the microbes themselves.
  • a typical formulation consists of: 23.28 g sucrose, l ⁇ .36g glucose, 0.28 g fructose, 1.76 g citric acid, 1.76 g sodium chloride, 1.52g potassium chloride, 1.68 g sodium bicarbonate per litre of solution.
  • far simpler formulations are also effective and may contai only glucose or sucrose, sodium chloride, potassium chloride and sodium bicarbonate.
  • the simplest rehydration formulations may contain only glucose and sodium chloride though preferably they also contain potassium chloride. This simple but effective treatment has resulted in a considerable reduction in infant mortality due to gastro-intestinal infections. It should be noted that, apart from typhoid, cholera and some forms of dysentery, antibiotics are not needed for the treatment of most gastro-intestinal infections and, in any case are not generally available in developing countries.
  • the present invention provides a simple process for producing clear water free of pathogenic microorganisms and of the enterotoxins of V. cholerae and Shigella species without the need for chemical disinfection or boiling.
  • the process may be used to provide water for drinking or cooking, for medical uses such as in making up and administering drugs by injection or intravenous infusion, for blood or plasma substitutes and for producing oral rehydration compositions.
  • the process may be used in developing countries, particularly during times of natural disasters. It could also be used in other countries by followers of outdoor pursuits such as campers, walkers and mountaineers to supply microbe-free drinking water from streams and rivers and by medical ' teams denied access to regular supplies of safe water.
  • a particular advantage of the present method is the low weight of the equipment required to produce the desired clean water. In a particular aspect the method described not only provides a microbe-free and enterotoxin-free supply of water but also provides a solution suitable for oral rehydration therapy.
  • the present invention therefore provides a process for producing a non-toxic solution of a least one water-soluble solid substantially free of micro-organisms which method comprises retaining the solid or a concentrated solution thereof in a container provided with a selectively permeable membrane in contact with the solid or solution and contacting the opposed side of the membrane with water for a predetermined minimum period of time so as to allow the water to enter the container by osmosis but to prevent the passage into the container of microorganisms from the water.
  • the selectively permeable membrane permits the passage of water and low molecular weight solutes into and out of the container. When placed in contact with water the membrane therefore allows water to enter the container and dissolve the solid. As the contact time increases more water is drawn into the container by osmotic pressure thereby diluting the solution of the solid. If the solid has a molecular weight below the molecular weight cut-off or exclusion size of the membrane material it will diffuse out of the container and both processes result in a gradual dilution of the solution.
  • the process thus permits the formation of solutions of specified concentration or, by continuing until substantially infinite dilution is achieved, the process permits the production of water almost free of the original water-soluble solid suitable for use, for example, as drinking water. Meanwhile the membrane prevents the ingress of micro-organisms and enterotoxins such as those of V. cholerae and Shigella species so that the water produced will, provided that the water soluble solid and the inside of the container were initially sterile and are not subsequently contaminated during handling, be substantially free of micro-organisms and these enterotoxins.
  • absolute sterility is not necessary; in such situations the water soluble solid and the inside of the container would be clean and free of harmful amounts of pathogenic micro-organisms.
  • absolute sterility is essential; in these instances the water soluble solid and the interior of the container will be produced in a sterile manner or subsequently sterilised and thereafter maintained sterile until used.
  • substantially free of micro-organisms means that the product contains le-s.s than 1 viable cell or spore per ml. using any appropriate readily available or specially produced selectively permeable membrane material and any water-soluble solid (which may be sterilised if necessary)
  • Typical membrane materials have a molecular weight cut-off in the range of 12-14 kiloDaltons (kD) which will exclude ulticellular parasites, protozoa, bacteria, fungi and viruses which may be present in the water outside the tubing and which will exclude enterotoxins such as those o V. cholerae and Shigella species.
  • enterotoxins such as the heat stable enterotoxin of Escherichia coli
  • Some enterotoxins have lower molecular weight but could be excluded using a membrane with a molecular weight cut-off of about 4 kD.
  • Such membranes will also exclude endotoxins since these have a molecular weight exceeding 1,000 Kilodaltons.
  • Endotoxins pyrogens of bacterial origin
  • the invention can therefore be used to provide solutions suitable for intravenous administration.
  • a variety of semi-permeable materials with different molecular weight cut-offs is available so that there ' is a wide choice. These materials include: a, cellulose - widely used to demonstrate the phenomenon o osmosis and in the purification of substances by dialysis. b, cellophane c, benzoylated cellulose d, viscose cellulose e, collagen.
  • the preferred material is cellulose since this can be obtained in a very pure form, is non-toxic, is not easily torn or broken when wet and can be left in water for long periods of time without deterioration.
  • the preferred molecular weight cut-off is 12 - 14 kiloDaltons since this will exclude all microbes and the important enterotoxins (ie, those of Vibrio cholerae, Shigella species, Campylobacter jejuni and the heat-labile enterotoxin of Escherichia coli) . In addition it is the most widely used material for dialysis and so is cheap and readily available.
  • the solid is present only to secure ingress of water and will be substantially entirely removed before the water is used. In such a situation the nature of the solid is irrelevant, however it will generally be preferred that it has a low molecular weight and that it is non-toxic at least at the final (minimal) concentration. Clearly, if it is to be substantially completely removed by diffusion, the solid must have a molecular weight below the molecular weight cut-off of the membrane.
  • the solid is required to be present in the final solution produced by the process.
  • the solid may be retained entirely within the container if its molecular weight is higher than the molecular weight cut-off of the membrane, such as in the case of dextrins, dextrans or certain water soluble glucose polymers [see The Economist, 27th May: 118-120 (1989)].
  • a balance must be struck between the losses to the water outside the container and the time required to secure ingress of sufficient water to establish the desired final concentration.
  • the membrane For production of water with the solid at minimal concentration it is preferable to contact the membrane with running water. Where a particular final concentration of solid is required, this may be achieved using running water but is preferably achieved using a predetermined starting volume of water; in the latter case the water may be static or agitated.
  • the desired final concentrations can be achieved within a period of from 1 to 24 hours, preferably 2 to 12, for instance 3, 4, 6, 8 or 10 hours.
  • the starting amounts of each solid will be adjusted having regard both to the osmotic effect and the rate of diffusion from the container of each. Further details can be seen in the Examples below. In such a case it will be preferable to contact the membrane with a predetermined starting volume of water, when simple trial and error will lead to a determination of the necessary minimum (and maximum) contact time.
  • a simple way to ensure the final concentration of a solute which has a molecular weight below the molecular weight cut-off of the membrane is to contact the membrane with a predetermined starting volume of water and continue the contact, with or without agitation, until equilibrium is achieved between the concentrations inside and outside the container.
  • sufficient solid is included within the container to achieve the desired concentration in the predetermined starting volume and the predetermined minimum contact time is the time required to establish equilibrium.
  • the water soluble solid is a mixture of solutes one or more of which has a molecular weight below the molecular weight cut-off; contact with the water is maintained until all such solutes have reached equilibrium.
  • water soluble solids which may be included within the container are dried blood products, blood- or plasma-substitutes, components of more complex oral rehydration formulations such as other electrolytes or amino acids and nutritional components such as dried nutritional substances, milk solid.s and partly dehydrated food containing water-soluble solids. Such solids may be added to the nutritional component if none are present in the component itself.
  • Other favoured solids for water gathering and nutritional purposes are rice powder solutes and rice powder.
  • Nutritional suspensions produced according to the process of the invention may be heated during or after the collection of water by the water-soluble solid.
  • Oral rehydration compositions based on a sugar such as glucose, sucrose or fructose and at least one electrolyte, such as sodium chloride may be produced by the process of the present invention. Preferably they are produced by contacting the membrane with a predetermined starting volume of water for sufficient time for the electrolyte(s) to equilibrate inside and outside the container and for enough of the sugar to diffuse out to leave the desired sugar and electrolyte concentrations inside the container.
  • solutes may be introduced into the container by diffusion from the external (dirty) water either during initial collection of water by the water-soluble solid or as a subsequent separate step.
  • the invention provides a method which comprises adding a mixture of chemicals of known ' composition to tubing formed from a semi-permeable material (ie. a material which will permit the passage of molecules below a certain molecular weight- the "molecular weight cut-off"), sealing the tubing at both ends (by tyin knots or by other means and then immersing the tubing in water.
  • a semi-permeable material ie. a material which will permit the passage of molecules below a certain molecular weight- the "molecular weight cut-off”
  • sealing the tubing at both ends by tyin knots or by other means and then immersing the tubing in water.
  • Water outside the tubing passes through the semi-permeable membrane resulting in a concentrated solution of the mixture inside the tubing. Since this concentrated solution has a higher osmotic pressure than the water outside the tubing, more water diffuses into the tubing so that the total volume of solution inside the tubing gradually increases.
  • the invention will also provide a solution suitable for oJal rehydration therapy if some attention is given to the duration of immersion of the tubing in the water.
  • the duration of immersion required will depend upon the material of construction of the tubing and the amount and composition of the original mixture contained inside the tubing (see example below).
  • the container and membrane used in the present invention may take any convenient form.
  • the container For production of drinking water on a large scale the container may be provided with a membrane of large surface area in a form adapted to contact flowing or static water such as a river or reservoir and the container may be provided with a means for adding further water-soluble solid and/or drawing off purified water.
  • the container On a smaller scale, such as for use in the production of individual doses of oral rehydration formulation, the container may simply be the membrane in tube form having at least one closed end. Such a container (or at least the closed end thereof) would be immersed in a container such as a bucket or jug of water in order to provide quantities of from a few ml to 1 litre e.g.
  • the container may be provided with an integral outer container for the impure water to be purified and/or with means for drawing off purified water, such as a mouthpiece, drinking tube, septum, hypodermic needle optionally with associated syringe or intravenous infusion set.
  • the container may be reusable and provided with a plurality of water-tight sealed compartments each containing a quantity of water soluble solid.
  • compartments would be opened to release the enclosed solid each time the reusable container is used; the compartments may be provided with any conventional means for opening such as screw or click-fit caps, break lines or other weak points or they may simply be opened by cutting or tearing depending upon the material, construction method and final intended use.
  • Such compartments containing quantities of drugs, additional solutes, insoluble materials or liquids may be provided in the containers such that the contents can be released into the purified water once the membrane has been removed from the impure starting water; by this means accurate dosing may be achieved and the loss by diffusion into the starting water of expensive or rare materials may be prevented.
  • containers including a membrane and at least one water-soluble solid may be provided in continuous web form with tear-off perforations or other means for dividing individual containers from a multi-container web.
  • the containers may also be provided with means for protecting the membrane and/or other fragile, delicate or sterile components during transport and storage.
  • the container may also be provided with suspension means. Means may also be provided for preventing access to the clean solution until the impure water has been removed.
  • the container may also be provided with means for indicating that the predetermined minimum contact period has elapsed and/or means for indicating that the interior has ceased to be sterile. This could be achieved for instance for indication of contamination, by applying blue dextran of high molecular weight to the exterior of the membrane whereby contaminated water is coloured. Thus any contamination of the "sterile" solute (if, for example, the membrane has been breached) would be indicated by a blue colouration of the solution.
  • an indicator strip similar to that used in urine sampling may be used. Such strips may have several sections containing different indicators such that colour indications of (e.g.) pH, glucose, sodium, potassium and chloride concentrations are given.
  • Indicator strips of this kind are available from BDH Limited (Poole, UK).
  • the preferred shape of the material is as a long narrow tube since this will increase the surface area/volume ratio enabling a more rapid uptake of water.
  • a variety of oral rehydration formulations have been suggested, one of the simplest being the "glucose electrolyte” solution recommended by the World Health Organisation. This consists of: sodium 90 mmol/1, potassium 20 mmol/1, chloride 80 mmol/1, bicarbonate 30 mmol/1, and glucose 111 mmol/1.
  • a more complex formulation consists of: sodium 50 mol/1, potassium 20 mmol/1, chloride 50 mmol/1, bicarbonate 20 mmol/1, glucose 91 mmol/1, fructose 2 mmol/1, sucrose 94 mmol/1 and citrate 9 mmol/1.
  • Flavouring agents may also be added to these formulations as well as high molecular weight soluble proteins and/or polysaccharides and any other components required in the final solution.
  • the water purifying system will consist of a length of semi-permeable tubing containing the oral rehydration mixture or other mixture of chemical compounds.
  • the tubing will have been sealed at one end by means of a clip or a knot or by heat-sealing or gluing.
  • the other end will preferably be sealed by means of a clip so that, after the tubing has been immersed in water overnight (or other suitable period of time), it can be re-opened to provide access to the purified water inside.
  • the water purifying system may be supplied in the form of a kit consisting of (1) a length of semi-permeable tubing, sealed at one end and funnelled at the other end (2) a clip for sealing the open end temporarily while the tubing is immersed in water and (3) an oral rehydration mixture or other mixture of chemical compounds.
  • the user will pour the mixture into the tube via the funnelled end, seal the funnelled end with the clip and immerse the tubing in water. After an appropriate period of immersion the user will remove the tubing from the water, wipe off any water adhering to the outside of the tubing, remove the clip and either pour the solution into another drinking container or drink the solution directly from the tubing using the funnelled end as a mouthpiece.
  • the tubing will then preferably be discarded since re-filling with fresh mixture would be technically difficult when the tubing was wet and contamination of the inside of the. tubing may take place if care was not exercised.
  • the composition of the mixture to be enclosed inside the tubing can be increased markedly (since the final concentration is not so critical as in the case of oral rehydration therapy) so that the rate of diffusion will correspondingly increase so that the duration of immersion of the tubing can be decreased.
  • high molecular weight water-soluble proteins and/or polysaccharides may be included in the mixture since these will also increase the rate of uptake of water.
  • flavouring agents to increase palatability of the drink will be of greater importance.
  • the invention further provides containers for use in the process described above and the use thereof in producing purified water and medicaments and methods for treating the human or animal body using solutions produced by the process of the invention.
  • solutions containers and methods form a farther aspect of the invention.
  • a method of providing a solution of non-toxic water-soluble solids effective to provide an osmotic pressure free of all micro-organisms and free of the enterotoxins of Vibrio cholerae and Shigella species which method comprises immersing in water a mixture of said compounds enclosed in a sealed drinking container provided with a membrane which is selectively permeable to allow the water to enter the container by osmosis but to prevent the passage into the container of micro-organisms or of molecules of molecular weight greater than 70 kiloDaltons until sufficient water has entered the container to dissolve the salts and diluted them to a concentration which renders the resultant solution drinkable.
  • the container comprises tubing sealed at each end, one end of which can be re-opened for use as a mouthpiece or to co-operate with a separate mouthpiece for drinking.
  • non-toxic water-soluble salts comprise a mixture with a composition such that it will result in a solution suitable for oral rehydration therapy.
  • F. A kit for use in a process described herein comprising (1) a mixture of solid chemical compounds for rehydration therapy, (2) a drinking container provided with a membrane as described herein and (3) means for temporarily sealing said container while it is immersed in water.
  • Such a kit wherein the drinking container comprises tubing permanently sealed at one end and wherein clip means are provided for temporarily sealing the other end.
  • Such a kit which further comprises funnel means co-operable with the container to provide both a mouthpiece for safe drinking from the container and a means for filling the container with the salts.
  • K Such a kit wherein the membrane is of cellulose or a derivative or regenerated form thereof.
  • L The use, in combination, of osmosis to provide water for dissolution of a mixture of water-soluble chemical compounds to form a solution for drinking or for use in rehydration therapy, and of simultaneous dialysis to exclude from the solution micro-organisms or harmful high molecular weight substances, a single membrane being used for the osmosis and dialysis.
  • Fig. 1. shows a partially cut-away front view of a container for use in accordance with the invention.
  • Fig. 2. shows a side view of the device of Fig. 1 and
  • Fig. 3. shows a front view of an alternative container for use in accordance with the invention.
  • Fig. 4. is a graph showing the results of Example 2.
  • the container 1 comprises hanging means 1, a filling spout with closure 3 and a septum 4 for drawing off purified water.
  • the container has two compartments respectively for dirty water 5 and purified water 6 separated by a divider 7 which is a selectively permeable membrane forming a water-tight seal with the walls of the container.
  • Compartment 6 is provided with a quantity of water-soluble solid 8 in contact with the divider 7.
  • dirty water is poured into compartment 5 via the filling spout to a predetermined level and the container is suspended from a suitable hook for a period of time during which the compartment 6 fills with purified water.
  • the residual dirty water may be discarded via the filling spout 3 before purified water is drawn off via the septum 4.
  • Alternative filling means and means for recovering purified water such as taps or spouts may be provided. It is not essential for the divider between the two compartments to be formed entirely of selectively permeable membrane material provided that a portion of the divider 7 in contact with the solid 8 is such material.
  • the arrangement of the divider 7 within the container is not critical and alternatives such as a horizontal or a diagonal divider are contemplated.
  • An alternative container for use in accordance with the present invention comprises a container as described in Figs 1 and 2 but, in place of a single quantity of solid 8, as shown in Fig. 3 the container is provided with a plurality of sachets 10 of solid or concentrated solution of solid.
  • the container of Fig 3 is used by bursting one of the sachets 10 and manipulating the solid so as to contact the membrane in the divider 7, then filling the compartment 6 with dirty water and recovering purified water as previously described. Once the residual dirty water has been discarded and the purified water recovered, the container may be reused by bursting a second sachet 10 and proceeding with a new volume of dirty water.
  • Additional sachets may be provided each containing solid or liquid components, such as drugs, for bursting and release of the solid or liquid components into the purified water.
  • the compartment for purified water may be sub-divided into a plurality of sealed compartments each provided with a portion or portions of water-soluble solid, a semi-permeable membrane and means for recovering water.
  • Different sachet may be coded, for instance colour coded, with each containing a different substance to be added.
  • the diameter of the tubing appears to affect the rate of uptake of water and the composition of the resulting solution.
  • the smaller diameter tubing has a greater rate of water uptake and glucose/salt loss than the larger diameter (Tables 1 and 2). This is presumably due to the greater surface area/volume ratio.
  • Varying the volume of water in which the formulation is immersed affects both the total volume of water taken up and the composition of the resulting solution. Hence, it is possible to obtain a solution of known composition by immersing the formulation in an appropriate volume of water. From the above results it ca be seen that for oral rehydration therapy, a solution of suitable composition can be obtained by immersing 10 g of the above formulation in from 400 to 500 ml of water.
  • the rate of water uptake and composition of the solution was dependent on the diameter of tubing used. Using 83mm tubing large quantities (650 ml) of a solution suitable for oral rehydration therapy was obtained after 1 h (Table 11). By extending the period of immersion beyond 16 h this method could also be useful for obtaining large quantities of sterile sucrose-containing solutions for drinking and other purposes. Water uptake by sucrose is appreciably more effective than with glucose.
  • Solutions with a composition suitable for oral rehydration therapy can be obtained after only 8h immersion in either 1, 1.5 or 2 litres of water (Table 12). Water uptake by sucrose is appreciably more effective than that attained with glucose.
  • dextran appears to be the most effective at taking up water.
  • Dextran solutions containing saline are commonly used as plasma substitutes administered by intravenous infusion.
  • the purpose of this experiment was to determine whether dextran could be used to draw in water through a semipermeable membrane and so obtain microbe-free solutions.
  • Dextran is effective at drawing in water across a semipermeable membrane although, unlike the other solutes tested, the uptake requires a long time before "saturation" is reached.
  • sucrose, glucose and sodium chloride A further point of difference from sucrose, glucose and sodium chloride is that the dextran cannot itself cross the semipermeable membrane (its molecular weight is 70,000) and therefore is totally retained within the tubing. This was verified by taking a 10 ml sample from the tubing and evaporating this to dryness, the dry weight of the recovered dextran showed that all of it had been retained in the bag.
  • a mixture suitable for oral rehydration therapy was prepared containing the following chemicals (per 100 g of mixture) 3.18g sodium chloride 2.75g potassium chloride 3.04g sodium bicabonate 3.18g citric acid 29.55g glucose 58.31g sucrose llg of this mixture was then poured into a 30 cm length of cellulose dialysis tubing with a diameter of 4.2 cm and a molecular weight cut-off of 12-14 kiloDaltons (Medicell Ltd., Islington*, London). The tubing was then sealed by tying a knot in each end (after carefully moistening each of the ends) and immersed in a large container through which was flowing a constant stream of tap water. After various time intervals the tubing was removed from the water and the volume of solution inside the tubing was measured. The solution was then poured back into the tubing which was then re-sealed and re-immersed in the flowing water.

Landscapes

  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Public Health (AREA)
  • Polymers & Plastics (AREA)
  • Epidemiology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Food Science & Technology (AREA)
  • Veterinary Medicine (AREA)
  • Medicinal Chemistry (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Medicinal Preparation (AREA)
  • Water Treatment By Sorption (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Medicines Containing Material From Animals Or Micro-Organisms (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
  • External Artificial Organs (AREA)
  • Cleaning By Liquid Or Steam (AREA)
  • Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
  • Catching Or Destruction (AREA)
  • Steroid Compounds (AREA)
  • Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)

Abstract

Procédé permettant de produire une solution non toxique à partir d'au moins un solide soluble dans l'eau ne contenant pratiquement pas de micro-organismes (8), qui consiste à placer le solide (8) dans un récipient (1) muni d'une membrane perméable de manière sélective (7) qui touche le solide (8), et à mettre en contact avec de l'eau l'extrémité opposée de la membrane (7) pendant un laps de temps minimum donné, de sorte à permettre à l'eau mais non pas aux micro-organismes qui y sont contenus de pénétrer dans le récipient (1) par osmose. La solution peut servir dans la thérapie orale de rehydration, ou être sous forme d'eau potable, de solution médicale, de produit à base de sang séché de succédanés de sang ou de plasma pour administration à un patient, de suspensions nutritives d'une substance nutritionnelle séchée, de solides à base de lait ou d'aliments partiellement déshydratés. On décrit également des récipients servant à réaliser ce procédé.
EP89911270A 1988-09-23 1989-09-22 Procede de purification de l'eau Pending EP0435944A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8822470 1988-09-23
GB8822470A GB2223696A (en) 1988-09-23 1988-09-23 Water purifying system

Publications (1)

Publication Number Publication Date
EP0435944A1 true EP0435944A1 (fr) 1991-07-10

Family

ID=10644176

Family Applications (2)

Application Number Title Priority Date Filing Date
EP89911270A Pending EP0435944A1 (fr) 1988-09-23 1989-09-22 Procede de purification de l'eau
EP89309658A Expired - Lifetime EP0360612B1 (fr) 1988-09-23 1989-09-22 Système de purification d'eau

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP89309658A Expired - Lifetime EP0360612B1 (fr) 1988-09-23 1989-09-22 Système de purification d'eau

Country Status (19)

Country Link
EP (2) EP0435944A1 (fr)
JP (1) JPH07102350B2 (fr)
KR (1) KR960003544B1 (fr)
AT (1) ATE139984T1 (fr)
AU (1) AU631574B2 (fr)
BG (1) BG61032B1 (fr)
BR (1) BR8907671A (fr)
CA (1) CA1323311C (fr)
DE (1) DE68926766T2 (fr)
DK (1) DK51291D0 (fr)
ES (1) ES2091764T3 (fr)
FI (1) FI105268B (fr)
GB (1) GB2223696A (fr)
GR (1) GR3021192T3 (fr)
HU (1) HU214482B (fr)
IE (1) IE75213B1 (fr)
OA (1) OA09640A (fr)
RO (1) RO106725B1 (fr)
WO (1) WO1990003333A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998004335A1 (fr) * 1996-07-29 1998-02-05 Kimberly-Clark Worldwide, Inc. Procede d'utilisation d'un filtre modifie par une charge cationique
GB9705456D0 (en) * 1997-03-17 1997-05-07 Ucb Sa Yoghurt production process
GB9705455D0 (en) * 1997-03-17 1997-05-07 Ucb Sa Self-rehydrating container
GB9705454D0 (en) * 1997-03-17 1997-05-07 Ucb Sa Membrane structure and bag comprising IT
EP1559685A3 (fr) * 2000-11-09 2007-04-25 The Polymer Technology Group, Inc. Dispositifs changeant de dimensions et de formes par pression osmotique
GB2442941A (en) * 2006-10-21 2008-04-23 Philip Peter Monro A method for the generation of water with reduced ionic solutes
US8702995B2 (en) * 2008-05-27 2014-04-22 Dober Chemical Corp. Controlled release of microbiocides
EP2869911A4 (fr) * 2012-07-09 2016-05-11 Fosmo Med Inc Dispositifs utilisant une osmose directe médiée par membrane

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1224528A (en) * 1968-12-20 1971-03-10 Aqua Chem Inc Method of sealing a semipermeable membrane
US3696931A (en) * 1969-04-16 1972-10-10 William T Hough Vessel having an osmotic membrane as an enclosing part thereof
US3702820A (en) * 1970-03-27 1972-11-14 William T Hough Solvent extraction into comestible solute
CH623233A5 (en) * 1975-05-02 1981-05-29 Ingerthorpe Holdings Ltd Device and method of preparing an aqueous solution for medical purposes
DE2964379D1 (en) * 1978-11-25 1983-01-27 Knut Stache Apparatus for producing a potable liquid from sea-water, polluted water and the like by osmosis
DE2851105A1 (de) * 1978-11-25 1980-05-29 Knut Stache Osmotisches meerwasserentsalzungsgeraet fuer seenotfaelle

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9003333A1 *

Also Published As

Publication number Publication date
BG61032B1 (bg) 1996-09-30
DE68926766D1 (de) 1996-08-08
EP0360612B1 (fr) 1996-07-03
AU4406889A (en) 1990-04-18
DK51291A (da) 1991-03-21
OA09640A (en) 1993-04-30
HU895685D0 (en) 1991-10-28
GB8822470D0 (en) 1988-10-26
GR3021192T3 (en) 1996-12-31
WO1990003333A1 (fr) 1990-04-05
KR960003544B1 (en) 1996-03-15
JPH04502120A (ja) 1992-04-16
HU214482B (hu) 1998-03-30
GB2223696A (en) 1990-04-18
IE75213B1 (en) 1997-08-27
EP0360612A1 (fr) 1990-03-28
ATE139984T1 (de) 1996-07-15
ES2091764T3 (es) 1996-11-16
AU631574B2 (en) 1992-12-03
JPH07102350B2 (ja) 1995-11-08
RO106725B1 (ro) 1993-06-30
BG94104A (bg) 1993-12-24
KR900701665A (ko) 1990-12-04
BR8907671A (pt) 1991-07-30
HUT61950A (en) 1993-03-29
DK51291D0 (da) 1991-03-21
IE893046L (en) 1990-03-23
FI911392A0 (fi) 1991-03-22
DE68926766T2 (de) 1997-02-13
CA1323311C (fr) 1993-10-19
FI105268B (fi) 2000-07-14

Similar Documents

Publication Publication Date Title
US4690772A (en) Sterilant compositions
US5192459A (en) Sterilant compositions
KR900017615A (ko) 침전물이 없는 투석용액
JP5266267B2 (ja) 水素含有生体適用液の製造方法及び製造装置
WO2010103894A1 (fr) Procédé et appareil de production d'une solution biocompatible contenant de l'hydrogène
AU2002356899A1 (en) Bicarbonate-based solutions for dialysis therapies
AU631574B2 (en) Water purifying system
Daniels et al. Glucose and glycerol compared as osmotic agents for peritoneal dialysis
AU613262B2 (en) Viricidal blood bag system
US5846522A (en) Fluoridation and refluoridation of water based compositions
RU2036846C1 (ru) Способ получения нетоксичного свободного от микроорганизмов раствора
Torres-Pinedo et al. Studies on infant diarrhea. III. Changes in composition of saline and glucose-saline solutions instilled into the colon
Oettinger et al. An economical new process for incenter bicarbonate dialysate production: comparison with acetate in a large dialysis population
CN118000213A (zh) 高纯长效即用型二氧化氯水溶液
RU1808329C (ru) Полионный дезинтоксикационный раствор дл разделительных процессов на полупроницаемых мембранах
Rubin et al. Evaluation of Stagnant Fluid Films During Simulated Peritoneal Dialysis: In-Vitro and In-Vivo Studies
Flowers A study of the bacterial flora contaminating haemodialysis fluids
Wing et al. Principles of dialysis
Boot A NEW FORM OF PYKNOMETER.

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 19910409

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

XX Miscellaneous (additional remarks)

Free format text: VERFAHREN ABGESCHLOSSEN INFOLGE VERBINDUNG MIT 89309658.6/0360612 (EUROPAEISCHE ANMELDENUMMER/VEROEFFENTLICHUNGSNUMMER) VOM 31.03.92.