Abstract: An object of the present invention is to provide a water purification cartridge in which the decreased function of the hollow fiber membranes is restored by cleaning and of which the operating cost of a purification treatment of raw water decreases. The present invention provides a water purification cartridge comprising a hollow fiber membrane element comprising a plurality of hollow fiber membranes bent in a U-shape and a potting material for binding both ends of the hollow fiber membranes so as to maintain the open states of the hollow fiber membranes and a cylindrical hollow fiber membrane case for covering the hollow fiber membranes, wherein the hollow fiber membrane element is detachably installed in the hollow fiber membrane case so that a fluid-tight state is maintained between the primary side and the secondary side of the hollow fiber membranes.

Abstract: A membrane filtration device has a multiplicity of hollow fiber membranes, or fibers, unconfined in a shell of a module; a first header and a second header disposed in vertically spaced-apart relationship; said first header and said second header having opposed ends of each fiber sealingly secured therein, all open ends of said fibers open to a permeate-discharging face of at least one header; permeate collection means to collect said permeate, sealingly connected in open fluid communication with a permeate-discharging face of at least one of said headers; means to withdraw said permeate; said fibers, said headers and said permeate collection means together forming an integrated combination wherein said fibers are essentially vertically disposed and ends of individual fibers are potted in closely spaced-apart relationship in cured resin; with opposed faces at a fixed distance; each of said fibers having a length from 0.1% to less than 5% greater.

Abstract: A membrane filtration manifold for connecting a filter submodule including one or more elongate bundles of semipermeable polymeric fibers is provided. The manifold includes a housing and connecting collar connected with said housing. The collar is adapted to receive and locate the submodule, where the submodule has a connecting sleeve with a locking formation. The submodule can be secured at one end to the collar by a clip adapted to engage both the collar and the locking formation to prevent axial withdrawal of the submodule from the collar. Also disclosed is a membrane filtration apparatus including a filter submodule including one or more elongate bundles of semipermeable polymeric fibers. The apparatus further includes a membrane filtration manifold removably connected at one end of said filter submodule and a basepiece removably connected to the other end of said filter submodule.

Abstract: The present invention provides methods for producing single and multi-layered coiled hollow fiber bundles for use in separation modules whose performance can be predicted, said modules being designed to take advantage of the benefits of Dean vortices. The present invention is also directed to multi-layered coiled hollow fiber bundles for use in separation modules that are directly scalable because each layer performs substantially equivalently to the other layers when subjected to a fluid of a certain velocity such that Dean vortices are created.

Abstract: The present invention provides a gas-permeable hollow fiber membrane having an inner diameter of 50 to 500 &mgr;m and a membrane thickness of 10 to 150 &mgr;m, which is, preferably a composite hollow fiber membrane having a three-layer structure consisting of a nonporous layer having porous layers disposed on both sides thereof. Dissolved gases present in an ink can be removed by passing the ink through the bores of hollow fibers comprising such a hollow fiber membrane, and evacuating the outer surface side of the hollow fibers. This method makes it possible not only to degas inks with a slight pressure loss, but also to degas inks stably even if pressure changes occur during degassing.

Abstract: A method is provided for measuring the local hydraulic permeability, Lpi, of a sub-group of hollow fibres of a bundle of hollow fibres mounted in a tubular casing. The method comprises a step of placing the casing containing the bundle in a vertical position, the lateral opening of the casing being disposed toward the bottom, and sealing the lower end of the casing. A graduated, calibrated tube is applied in a vertical position over a portion of the upper cut surface of the bundle to form a sealed connection there between. A liquid is passed through the lateral opening of the casing at a defined flow rate, and the time required for the liquid to pass from a first graduation to a second graduation of the tube is measured.

Abstract: A method and apparatus for cleaning a membrane module, the membrane module having a plurality of porous membranes, the membranes being arranged in close proximity to one another and mounted to prevent excessive movement therebetween and means for providing, from within the module, by means other than gas passing through the pores of the membranes, gas bubbles entrained in a liquid flow such that, in use, the liquid and bubbles entrained therein move past the surfaces of the membranes to dislodge fouling materials therefrom, the gas bubbles being entrained in the liquid by flowing the liquid past a source of gas to draw the gas into the liquid flow. The gas bubbles are preferably entrained into the liquid using a venturi type device. The membranes are preferably partitioned into discrete groups to assist cleaning while maintaining high packing density.

Abstract: The present invention relates to filtration media having both hydrophobic (water-repellent) properties. The filtration media are produced using a fluorothermoplastic material, such as a terpolymer of tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene. The invention also relates to methods of preparing such filtration media using casting solution phase inversion.

Abstract: It is intended to provide a blood purification membrane having excellent performance and showing little elution of blood and little adhesion of blood proteins or platelets. The above object can be achieved by using a moisten membrane, which is free from any membrane pore-sustaining agent and has a high water permeation dose and a large pore size, and lessening the pore size by drying the membrane after desolvation.

Abstract: An apparatus for filtering a liquid in a tank has a plurality of elements and a frame for holding the elements while they are immersed in the liquid. The elements have a plurality of hollow fibre membranes attached to and suspended between an upper header and a lower header. The membranes are in fluid communication with one or more permeate channels in one or more of the headers. Releasable attachments between the headers and the frame allow the frame to releasably hold the elements by their headers. The size and configuration of the frame determines the positions of the upper and lower headers of each element relative to each other. Connections between the permeate channels and one or more permeate collection tubes attached to the frame are releasable and resealable connections which are made or broken automatically by the movements involved in inserting or removing an element into or out of the frame.

Abstract: Porous hollow polymer fiber membranes having convoluted inside and/or outside surfaces, as well as filter devices comprising a plurality of the hollow fiber membranes, the devices preferably being arranged to direct fluid flow from the inside surface of the membranes to the outside surface, methods of making the membranes, and methods of using the filter devices, are disclosed.

Abstract: High flux porous hollow fiber membranes are produced from perfluorinated thermoplastic polymers by extruding a heated solution of the polymer having a lower critical solution temperature directly into a cooling bath to form the porous membrane by liquid-liquid phase separation. Extrusion can be conducted either vertically or horizontally.

Abstract: An in-vivo plasmapheresis and/or in-vivo ultrafiltration membrane comprises a plurality of elongated hollow fibers each fiber having an interior lumen extending along the fiber length, the fiber wall having a plurality of zones between the inner and outer wall surfaces, each of the zones having a mass density different than the mass density of an adjacent zone. The fiber wall is characterized by having a lower mass density zone at the inner wall surface and a higher mass density zone at the outer wall surface.

Abstract: High flux porous hollow fiber membranes are produced from perfluorinated thermoplastic polymers by extruding heated solution of the polymer having a lower critical solution temperature directly into a cooling bath to form the porous membrane by liquid-liquid phase separation. Extrusion can be conducted either vertically or horizontally.

Abstract: An in-vivo plasmapheresis and/or in-vivo ultrafiltration membrane comprises a plurality of elongated hollow fibers each fiber having an interior lumen extending along the fiber length, the fiber wall having a plurality of zones between the inner and outer wall surfaces, each of the zones having a mass density different than the mass density of an adjacent zone. The fiber wall is characterized by having a lower mass density zone at the inner wall surface and a higher mass density zone at the outer wall surface.

Abstract: A filter for an extracorporeal blood circuit including a bundle of hollow fibers having an end section encased in a potting material, wherein the end section of potting material has an end surface with open ends of the fibers distributed throughout the end surface, and a filter header cap having an inlet connectable to a blood line and an open end sealed around a side surface of the end section of the bundle of hollow fibers.

Abstract: A method and apparatus for cleaning a membrane module, the membrane module having a plurality of porous membranes, the membranes being arranged in close proximity to one another and mounted to prevent excessive movement therebetween and means for providing, from within the module, by means other than gas passing through the pores of the membranes, gas bubbles entrained in a liquid flow such that, in use, the liquid and bubbles entrained therein move past the surfaces of the membranes to dislodge fouling materials therefrom, the gas bubbles being entrained in the liquid by flowing the liquid past a source of gas to draw the gas into the liquid flow. The gas bubbles are preferably entrained into the liquid using a venturi type device. The membranes are preferably partitioned into discrete groups to assist cleaning while maintaining high packing density.

Abstract: Filter membranes for efficiently eliminating pathogens such as viruses from solutions of drugs or physiologically active substances employed as starting materials thereof which are contaminated with pathogens such as viruses. These filter membranes, which can simultaneously achieve favorable performance of eliminating small viruses and a high physiologically active substance-permeability, can be obtained by controlling the membrane characteristics to give a ratio (BP/&ggr;) of the bubble point BP (MPa) to the surface tension &ggr; (N/m) of 110 or above, and/or logarithmic elimination ratios of swine parvovirus at 0 to 5 l/m2 filtration volume and at 50 to 55 l/m2, and regulating the permeability for bovine immunoglubulin, wherein the monomer content amounts to at least 80%, to 70% or more. These filter membranes make it possible to provide drugs or starting materials therefor with little fear of the contamination with viruses, etc. and, therefore, are useful in the fields of pharmacy, medicine and the like.

Abstract: A laminar structure (17) comprising a deposited metal, the structure having microholes (17a) extending between a first surface and a second surface thereof, each microhole having a wall which meets the first surface with a rounded edge or tapered configuration in such a manner that the first surface is substantially smooth.

Abstract: EVAL microporous hydrophilic hollow fiber membranes are formed from a casting dope that includes low and high molecular weight pore-formers. Post-fabrication treatment includes stretching, hot water soaking and crosslinking.

Abstract: A hollow fiber membrane module comprising a module housing, a hollow fiber membrane bundle comprising a plurality of hollow fiber membranes, at least one end portion of the bundle being fixed on the housing through a flexible potting material, and a rib or ring embedded in the potting portion, the rib or ring being fixed on an inner wall of the housing, and the rib or ring being embedded in the potting portion without directly contacting the hollow fiber membrane, and the filtration method using the same. The hollow fiber membrane module can maintain a practical pressure resistance.

Abstract: A method and apparatus for removing fouling materials from the surface of a plurality of porous membranes (9) arranged in a membrane module (4) by providing, from within the module, by means (10) other than gas passing through the pores of said membranes, gas bubbles in a uniform distribution relative to the porous membrane array such that the bubbles move past the surfaces of the membranes (9) to dislodge fouling materials therefrom. The membranes (9) are arranged in close proximity to one another and mounted to prevent excessive movement therebetween. The bubbles also produce vibration and rubbing together of the membranes to further assist removal of fouling materials.

Abstract: A separation column for chromatography or a medium for solid phase extraction, which comprises a hollow capillary and a collected body packed in the hollow capillary and serving as a stationary phase, the collected body comprising long fibers having an adsorbing ability selective towards a target solute and arranged in the axial direction of the capillary, and a sample injection system which comprises the foregoing hollow capillary incorporated into a loop of a valve or a passage connecting two valves, the valve(s) being used as an injector for the chromatography. The use of the polymeric long fibers, which have chemical structures specially designed so that they can specifically interact with a target substance (a solute or an analyte) to be analyzed, permits the selective or preferential extraction and/or concentration of the solute.

Abstract: A filter device has two flow paths. The first flow path having at least one cap and fluid port. The second flow path surrounding the first fluid flow path and having at least one cap that overlaps the cap of the first fluid flow path. The second flow path also having at least one fluid port. The filter device providing a simple arrangement that is easily disinfected or sterilized.

Abstract: A hemodiafiltration system for treating blood which has module having a housing in which hollow-fiber membranes are arranged in the direction of the longitudinal extent and are embedded at their ends in first and second sealing compounds joined to the inner wall of the housing in a fluid-tight manner. The membrane module also has a dialyzate space and a substituate space separated from the dialyzate space in a fluid-tight manner by a continuous dividing wall. The membrane module further includes means for delivering and withdrawing a dialyzate to and from the dialyzate space, and means for delivering a substituate to the substituate space. The hollow-fiber membranes are used for blood treatment, filtration of the substituate, and delivery of the substituate to the blood.

Abstract: The present invention relates to a composite semipermeable membrane, which is useful as a reverse osmosis membrane or a nano-filtration membrane and comprises a polysulfone porous support membrane and a polyamide ultrathin layer formed on one of the surfaces of the porous support membrane, the composite membrane having the characteristic that in the infrared absorption spectrum obtained from the surface of a polyamide ultrathin layer of the composite semipermeable membrane, the ratio T (=Aa/As) of absorption intensity Aa at the absorption peak revealing C═O of polyamide in the region of 1600-1700 cm−1 to absorption intensity As at the absorption peak revealing polysulfone at a wavenumber around 1586 cm−1 is at least 0.05 and not higher than 3.

Abstract: The invention relates to a bundle of hollow fibers intended to constitute the membrane of a device for treating blood or plasma by extracorporeal circulation, in which: the hydraulic permeability of the hollow fibers in the bundle is heterogeneous; and the ratio of the highest hydraulic permeability measured on some hollow fibers of the bundle to the lowest hydraulic permeability measured on other hollow fibers in the same bundle is at least about 5. The invention also relates to a method for producing such a bundle, and a device comprising such a bundle.

Abstract: A dialyzer including a substantially cylindrical case 2, a hollow fiber bundle 3 made of a plurality of hollow fiber membranes provided in the case 2, a blood flow path formed by lumens of the hollow fiber membranes, a dialysate flow path formed by a gap between the inner wall of the case 2 and the hollow fiber membranes, and a cylindrical elastic tube 4 inserted in the gap between the inner wall of the case 2 and the hollow fiber bundle 3.

Abstract: The present invention relates to a method for producing a hollow fiber membrane module or a capillary membrane module as well as a device having such a module. In the method, hollow fibers or capillaries (3) are placed, in an unsintered state, in a mold (1) structured for receiving the hollow fibers or capillaries (3) and are sintered once inside the mold (1). Subsequently or simultaneously, the fibers are potted in the mold.

Abstract: A submerged, vertically-mounted membrane device, the device receiving a gas-sparged feed stock at a bottom feed inlet to provide airlift circulation of the feed stock through the device and separating the feed stock into filtrate and residual gas-containing retentate which passes from the top end of the device. The device comprises a structure of one or more monolith segments of porous material each monolith segment defining a plurality of passageways extending longitudinally from a bottom feed end face to a top retentate end face. A porous membrane is applied to the walls of the monolith segment passageways to provide a separating barrier. At least one filtrate conduit within the device carries filtrate from within the device toward a filtrate collection zone of the device, and the filtrate conduit provides a path of lower flow resistance than that of alternative flow paths through the porous material. A seal is provided to separate feed stock and retentate from the filtrate collection zone.

Abstract: A porous multilayered hollow fiber for outer side pressed filtration is made of a multilayer comprising a supporting layer constituted of the thickness of an expanded porous polytetrafluoroethylene tube, and a filtration layer provided on the outer surface of the supporting layer, wherein pores surrounded by fibrous frameworks in the filtration layer are smaller than those of the supporting layer, and the mean of the maximum fibril length (L) of the fibrous frameworks surrounding each pore in the outer surface of the filtration layer is designed to be small such that (X) and (Y) fall within the range on the XY plane, where (X) is a particle diameter of particles captured when the particle trapping ratio is equal to or more than 90% in the case where the filtration is done under an elevated pressure of 0.1 MPa, and (Y) is a value designated as RFL obtained by dividing (L) by (X).

Abstract: Solvent-resistant polybenzimidazole membranes, methods of making them and crosslinking them and composite membranes and hollow fiber membrane modules from them are disclosed.

Abstract: A method and apparatus for removing fouling materials from the surface of a plurality of porous membranes (9) arranged in a membrane module (4) by providing, from within the module, by means (10) other than gas passing through the pores of said membranes, gas bubbles in a uniform distribution relative to the porous membrane array such that the bubbles move past the surfaces of the membranes (9) to dislodge fouling materials therefrom. The membranes (9) are arranged in close proximity to one another and mounted to prevent excessive movement therebetween. The bubbles also produce vibration and rubbing together of the membranes to further assist removal of fouling materials.

Abstract: This invention provides an inexpensive hollow-fiber membrane module that can prevent diaphragms from peeling or coming off from the cylindrical casing. The invention includes a hollow-fiber membrane module, comprising a cylindrical casing having an inlet port for the treating liquid at one end and an outlet port for the treating liquid at the other end, a hollow-fiber membrane bundle contained in the cylindrical casing, potting layers for fixing the hollow-fiber membrane bundle to the inner wall of the cylindrical casing at both the ends of the hollow-fiber membrane bundle, a header having an outlet port for the liquid undergoing treatment provided at one end of the cylindrical casing, and a header having an inlet port for the liquid undergoing treatment provided at the other end of the cylindrical casing, wherein baffle cylinders having slits extending in the direction at an angle to the axis of the cylindrical casing are fitted in the potting layers.

Abstract: An apparatus and method for recovering bioproducts from a feed solution. In one embodiment, the apparatus includes a module housing, a membrane means disposed in the housing for filtering the bioproducts from the feed solution wherein a portion of the membrane means is coated with a polymeric coating, and an adsorbent bed disposed in the housing for retaining the bioproducts which permeate through the membrane, wherein the apparatus is adapted to allow fractionation and purification of the retained bioproducts from the bed by elution.

Abstract: A porous asymmetric hollow polymer fiber membrane having an inside surface having a coarse porous structure and an outside surface having a dense porous structure, the average pore size rating of the pores at the inside surface being greater than the average pore size rating of the pores at the outside surface, as well as filters and filter devices comprising one or more of the hollow fiber membranes, the filter and devices preferably being arranged to direct fluid flow from the inside surface of the membranes to the outside surface, and methods of using the filters and filter devices, are disclosed.

Abstract: This invention relates to systems for treating wastewater and more particularly to removing nutrients from wastewater in a wastewater treatment system. Wastewater tanks, each having membrane filters, are arranged in series. Each tank is equipped with respective inlets and outlets and an air supply as well as detectors for monitoring various wastewater parameters. A controller is coupled to the detectors, inlets and outlets for effecting sequences of opening and closing the inlets and outlets and turning the air supplies on and off in response to various detecting conditions and effects different operations, including a cleaning mode, in different cycles.

Abstract: A modified hollow-fiber membrane which has improved surface hydrophilicity without increasing the amount of components released therefrom, is less apt to interact with living-body components, does not adsorb proteins, and is less apt to deteriorate in performance. The hollow-fiber membrane has a copolymer of 2-methacryloyloxyethylphosphorylcholine and other polymerizable vinyl monomer held on a surface of the membrane, the copolymer being present on the surface in a higher concentration than in other parts of the membrane. The modified hollow-fiber membrane is useful in medical applications such as hemodialysis and blood filtration and in the medical industry, food industry etc.

Abstract: A hollow fiber membrane cartridge wherein a cartridge head and a bottom ring are connected and fixed to each other by means of a plurality of rods or pipes, the hollow portion at the end of each hollow fiber membrane on the cartridge head side is open, the hollow portion at the end of each hollow fiber membrane on the bottom ring side is sealed, and a plurality of through-holes are provided in an adhesion and fixation layer on the bottom ring side and are located in a bundle of the hollow fiber membranes.

Abstract: Hollow fiber membrane cassettes (1000) comprising an exterior casing (400), a filter (20) comprising two or more hollow fiber membranes (21), and an internal manifold (50) comprising first and second cassette headers (51, 52), wherein the cassette is arranged to allow feed flow, retentate flow, and permeate flow, and methods for making and using the cassettes, are disclosed.

Abstract: An apparatus is described for withdrawing filtered permeate from a substrate contained in a reservoir at ambient pressure. The apparatus includes a plurality of membrane assemblies. Each assembly has a plurality of hollow fiber filtering membranes, immersed in the reservoir, at least one permeating header with the membranes sealingly secured therein, and a permeate collector to collect the permeate sealingly connected to the at least one permeating header and in fluid communication with lumens of the membranes. The membranes of each assembly extend generally vertically upwards from a first header during permeation. One or more sources of suction are provided in fluid communication with the lumens of the membranes of each assembly through the permeate collectors and apply sufficient suction to withdraw permeate from the lumens of the membranes. An aeration system for discharging bubbles assists in keeping the membranes clean.

Abstract: The present invention provides, inter alia, a composition useful for producing a homogeneous, semipermeable membrane, the composition comprising a polysulfone semipermeable membrane, the polysulfone semipermeable membrane comprising a mixture of: an ultra-high-molecular-weight hydrophilic polymer, a polysulfone compound and a solvent for the polysulfone compound, and the polysulfone semipermeable membrane having a homogeneous structure such that the polysulfone semipermeable membrane has a substantially uniform structure. Another aspect of this invention discloses methods for fabricating semipermeable membranes by homogeneously mixing the composition, melting the composition, and melt-spinning the molten composition. Another aspect of the present invention includes homogeneous, melt-spun, semipermeable membranes useful for liquid separation processes, such as, but not limited to, microfiltration, ultrafiltration, dialysis, and reverse osmosis.

Abstract: A separation membrane module having hollow fibers, wherein a plurality of hollow fibers are heated and melted to bond and thermally fuse the external surfaces of the hollow fibers with each other; and a method of manufacturing a separation membrane module having hollow fibers whereby the ends of a plurality of hollow fibers are inserted into a sheath, the sheath and the hollow fibers are tightly bonded together to form spaces, and the sheath portion into which hollow fibers have been inserted is heated up to the temperature at which the surfaces of the hollow fibers melt, with the spaces thus formed kept in a decompressed state, so that the exterior surfaces of the hollow fibers are thermally fused and integrated together.

Abstract: A system and a method for determining integrity of a dialyzer are provided. The dialyzer may have a gas, such as, for example, air, within the dialyzer. A liquid chamber may be connected to the dialyzer. Liquid within the liquid chamber may be directed toward the dialyzer. The air within the dialyzer may then be compressed. A monitor may be provided exterior to the dialyzer to measure a pressure decay within the dialyzer as the compressed air exits the dialyzer. A comparison between the pressure decay and a leak threshold associated with the dialyzer may assist in determining whether the dialyzer has a leak wherein the dialyzer is unacceptable for use.

Abstract: The invention relates to a hollow membrane (11) comprising two support layers arranged one above the other forming a space between them and a plurality of capillary tubes arranged between the support layers forming capillary channels for the flow of a first fluid, the space between the capillary tubes forming an internal cavity for the circulation of a second fluid around the capillary tubes, and the whole assembly being made of an organic polymer. These membranes (11) can be assembled into modules for the treatment of a fluid with intermediate porous panels (13).

Abstract: A method and apparatus for cleaning a membrane module, the membrane module having a plurality of porous membranes, the membranes being arranged in close proximity to one another and mounted to prevent excessive movement therebetween and means for providing, from within the module, by means other than gas passing through the pores of the membranes, gas bubbles entrained in a liquid flow such that, in use, the liquid and bubbles entrained therein move past the surfaces of the membranes to dislodge fouling materials therefrom, the gas bubbles being entrained in the liquid by flowing the liquid past a source of gas to draw the gas into the liquid flow. The gas bubbles are preferably entrained into the liquid using a venturi type device. The membranes are preferably partitioned into discrete groups to assist cleaning while maintaining high packing density.

Abstract: A filter device for mass exchange between two media separated by a membrane is disclosed. The device provides for low-stress transfer of blood flow from the connection area of the filter device to the fibers of a hollow fiber bundle. Relatively uniform utilization of the fibers is provided by a membrane in the form of a hollow fiber bundle whose fiber cavities form a first flow space. At least one inflow or outflow chamber is connected to the first flow space for supplying a medium to the hollow fiber bundle or removing a medium from the hollow fiber bundle. The inflow or outflow chamber is adjacent to an essentially circular or semicircular channel which is designed to be open in the direction of the ends of the hollow fibers and is connected to an inlet or outlet of the filter device. The channel is arranged approximately centrally with the hollow fiber bundle.

Abstract: High flux porous hollow fiber membranes are produced from perfluorinated thermoplastic polymers by extruding a heated solution of the polymer having a lower critical solution temperature directly into a cooling bath to form the porous membrane by liquid-liquid phase separation. Extrusion can be conducted either vertically or horizontally.

Abstract: A blood purifying apparatus having excellent purification performance (elimination of low molecular proteins, etc.) and being contaminated with little endotoxins flowing from the dialyzate side is described. Attention was paid to the solute permeability coefficient &agr; and water permeability performance Lp of blood purifying apparatus and the relation between &agr; and Lp has been examined. As a result, a blood purifying apparatus having excellent purification performance and substantially being free from invasion of endotoxins was obtained by regulating the value &agr;/Lp to 6×10−7 or above, or regulating &agr; within a range of 8×105 to 1.5×10−3, and the value &agr;×Lp to 2.4×10−2 or less. Also, a blood purifying apparatus having excellent purification performance and substantially being free from invasion of endotoxins was obtained by regulating the invasion ratio which is obtained by the polymer invasion test to 10% or less.

Abstract: The present invention relates to a cellulose compound hollow fiber membrane having high mechanical strength and is hardly degraded by microorganisms, wherein a cellulose compound is comprised as a membrane material, the thickness of the membrane is 50 to 500 &mgr;m, a dense membrane surface having an average pore diameter of 0.001 to 0.05 &mgr;m exists on the internal and/or external surface thereof, the inside of the membrane is composed of a three-dimensional network-like porous structure having voids with an average pore diameter of 0.05 to 2 &mgr;m, and 70% by weight or more of the membrane material is cellulose acetate propionate or cellulose acetate butyrate.