Abstract: A method of controlling fouling in a membrane filtration system (5) of the type where gas is used to clean or scour the membranes (6) wherein the method includes supplying the gas to the system with a continuously variable flow rate. A continuously variable valve arrangement (17) is also disclosed.

Abstract: A restraining system for hollow fibers is provided. The restraining system includes a plurality of longitudinally extending elements spaced from one another and supported by a number of discrete spacer elements, each spacer element extending generally transverse of said longitudinal elements, such that in combination with said longitudinal elements they define a cage-like structure.

Abstract: A method of concentrating the solids of a liquid suspension by providing a pressure differential across the walls of permeable, hollow membranes (6) immersed in the liquid suspension (9). The liquid suspension (9) is applied to the outer surface of the porous hollow membranes (6) to induce and sustain filtration through the membrane walls (12) wherein some of the liquid suspension passes through the walls (12) of the membranes (6) to be drawn off as clarified liquid or permeate from the hollow membrane lumens (11), and at least some of the solids are retained on or in the hollow membranes (6) or otherwise as suspended solids within the liquid (9) surrounding the membranes (6).

Abstract: A method and apparatus for reducing the effect of integrity loss in a hollow fiber membrane module, said module including a plurality of hollow fiber membranes (5), at least one end of the fiber membranes (5) being supported in a pot (6), the method including the step of increasing flow resistance of the liquid through the lumen (8) of the fiber membrane (5) in the region of the pot (6).

Abstract: A method and apparatus for reducing the effect of integrity loss in a hollow fibre membrane module, said module including a plurality of hollow fibre membranes (5), at least one end of the fibre membranes (5) being supported in a pot (6), the method including the step of increasing flow resistance of the liquid through the lumen (8) of the fibre membrane (5) in the region of the pot (6).

Abstract: A method of forming a pot for an array of hollow fibre membranes (7) is provided, including the steps of placing the ends (6) of the fibre membranes (7) in a mould (5); forming a first layer (20) of curable resin material in a non-cured state around the fibre membrane ends (6), applying a second layer (21) of a polyurethane resin material to the first layer (20) prior to full curing of the first layer, the polyurethane resin material layer being chemically reactive with the first layer material to form an adhesive bond therebetween; at least partially curing both layers and removing the pot formed from the mould (5), wherein the second layer material is of higher flexibility than the first layer material when each layer is fully cured. Apparatus for performing the method is also disclosed.

Abstract: A method of cleaning a membrane filtration module is disclosed. The module comprises at least one or more longitudinally extending membranes located in a feed-containing vessel. The membranes have a permeable wall which is subjected to a filtration operation wherein feed containing contaminant matter is applied to one side of the membrane wall and filtrate is withdrawn from the other side of the membrane wall. The method comprises the steps of suspending the filtration operation; performing a cleaning process on the membrane wall to dislodge contaminant matter from the membrane wall into liquid surrounding the membrane: performing a sweep of the feed-containing vessel substantially parallel to the longitudinally extending membranes to remove the liquid containing the dislodged contaminant matter, at least in part, through an opening in a header or other part of the module, and then recommencing the filtration operation.

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 method of forming a pot for an array of hollow fiber membranes (7) is provided, including the steps of placing the ends (6) of the fiber membranes (7) in a mould (5); forming a first layer (20) of curable resin material in a non-cured state around the fiber membrane ends (6), applying a second layer (21) of a polyurethane resin material to the first layer (20) prior to full curing of the first layer, the polyurethane resin material layer being chemically reactive with the first layer material to form an adhesive bond therebetween; at least partially curing both layers and removing the pot formed from the mould (5), wherein the second layer material is of higher flexibility than the first layer material when each layer is fully cured. Apparatus for performing the method is also 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: A restraining system for hollow fibers is provided. The restraining system includes a plurality of longitudinally extending elements spaced from one another and supported by a number of discrete spacer elements, each spacer element extending generally transverse of said longitudinal elements, such that in combination with said longitudinal elements they define a cage-like structure.

Abstract: The present invention relates a method for cleaning polymeric microfiltration membranes and membrane units, and to compositions useful in such methods. The compositions include at least one soluble sulfite reducing agent and a compatible solvent.

Abstract: A method of forming a pot for an array of hollow fibre membranes (7) is provided, including the steps of placing the ends (6) of the fibre membranes (7) in a mould (5); forming a first layer (20) of curable resin material in a non-cured state around the fibre membrane ends (6), applying a second layer (21) of a polyurethane resin material to the first layer (20) prior to full curing of the first layer, the polyurethane resin material layer being chemically reactive with the first layer material to form an adhesive bond therebetween; at least partially curing both layers and removing the pot formed from the mould (5), wherein the second layer material is of higher flexibility than the first layer material when each layer is fully cured. Apparatus for performing the method is also disclosed.

Abstract: A porous polymeric membrane formed from a blend of a polymeric membrane forming material, such as polyvinylidene fluoride or polysulfone and a polymeric reactivity modifying agent adapted to modify the surface active properties of the porous polymeric membrane. The reactivity modifying agent is preferably a linear polymeric anhydride, such as poly(alkyl vinyl ether/maleic anhydride). The surface activity modifications include modification of the hydrophilicity/hydrophobicity balance of the membrane, or hydrolysis followed by reaction with a polyamine to form a crosslinked polyamide layer. Such modified membranes have use as reverse osmosis membranes.

Abstract: A method and apparatus for reducing volume of feed liquid required in a porous membrane filtration system having a number of porous membranes (6) submersed in a volume of feed liquid to be filtered is provided, the method comprising the step of providing filler elements (9) within said volume of feed liquid to be filtered.

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 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 restraining system for hollow fibres is provided. The restraining system includes a plurality of longitudinally extending elements spaced from one another and supported by a number of discrete spacer elements, each spacer element extending generally transverse of said longitudinal elements, such that in combination with said longitudinal elements they define a cage-like structure.

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 method and apparatus for reducing volume of feed liquid required in a porous membrane filtration system having a number of porous membranes (6) submersed in a volume of feed liquid to be filtered is provided, the method comprising the step of providing filler elements (9) within said volume of feed liquid to be filtered.