Abstract: The invention discloses a kind of porous membrane filtration component for treating water, specifically it discloses a kind of suspending porous hollow fiber membrane bundle for treating highly turbid waste water. The component includes some porous hollow fiber membrane yarns and casting heads arranged at both ends of respective yarns, wherein the connections between the said casting heads and membrane filtration module are flexible connections, at least one end of the flexible connection the cast header is connected with a hollow tube or cord, and the membrane bundle hangs on the said membrane filtration module, suspending freely. The invention provides a suspending porous hollow membrane bundle that can effectively remove contaminants adhered to the surface of the membrane yarns, makes its membrane yarns difficult to rupture, has a longer service life, and produces water with steady quality.

Abstract: Aspects and embodiments of the present application are direction to systems and methods for treating fluids and to systems and methods for cleaning membrane modules used in the treatment of fluids. Disclosed herein is a membrane filtration system and a method of operating same. The membrane filtration system comprises a plurality of membrane modules positioned in a feed tank, at least one of the membrane modules having a gas slug generator positioned below a lower header thereof, the gas slug generator configured and arranged to deliver a gas slug along surfaces of membranes within the at least one of the membrane modules and a global aeration system configured to operate independently from an aeration system providing a gas to the gas slug generator, the global aeration system configured and arranged to induce a global circulatory flow of fluid throughout the feed tank.

Abstract: Desalination is accomplished by subjecting feed saline water to a cation exchanger in magnesium form where sodium and scale-forming cations are at least partially exchanged for non-scale-forming magnesium ions. This ion exchange also reduces the osmotic pressure of the solution. When the resultant solution is subjected to a pressure-driven membrane desalination process, scaling is reduced and desalinated water is efficiently produced at a lower pressure. After desalination, the concentrated waste water, which contains higher concentrations of ions such as magnesium and sodium, is used to regenerate the depleted cation exchanger back into magnesium form. This regeneration permits the process to be self-sustainable.

Abstract: According to one aspect of the present invention, there is provided a desalination system comprising a plurality of elongated pressure vessels (PV). Each PV has a longitudinal axis, oriented such that the longitudinal axis thereof is of a vertical orientation. Each of the PVs is adapted to receive therein a plurality n of desalination membranes. The membranes located above the lowermost membrane within the PV have a total weight allowing them to function as a mechanism limiting axial expansion of the lowermost membrane, whereby the PV is free of any additional limiting mechanism.

Abstract: A method and system for removing organic contaminants from water by use of a panel of hydrophobic polymer membranes which resist degradation when exposed to aggressive oxidizing solutions and that can be used to decompose the organic contaminants while fostering selective-permeation by the organic contaminants are disclosed.

Abstract: The present invention relates to a method of removing blood from an extracorporeal blood circuit following termination of a blood treatment session, wherein blood is concurrently removed both from an arterial conduit portion and from a venous conduit portion of the extracorporeal blood circuit. It further relates to a method for recognizing and/or eliminating air inclusions in or from an extracorporeal blood circuit and a treatment apparatus as well as a tube system.

Abstract: A cost effective continuous deep water desalination method and system that can use reverse osmosis, and use the difference in the relative density of fresh and salt water to raise desalinized water through a header into an inshore gathering line. The desalinized water can flow to shore via a gravity-driven elevation change. Inertial energy from the gravity drop can be captured prior to deposit to an aquifer or pumping to the land surface. This energy can be used to help drive the system. Wind, solar, and wave energy can also be captured to provide mechanical or electrical power to assist in driving the system. Back flushing the system can be performed through forcing the fresh water or air back through the system and thus force buildup off the membrane.

Abstract: An aeration system for a submerged membrane module has a set of aerators connected to an air blower, valves and a controller adapted to alternately provide a higher rate or air flow and a lower rate of air flow in repeated cycles. In an embodiment, the air blower, valves and controller, simultaneously provide the alternating air flow to two or more sets of aerators such that the total air flow is constant, allowing the blower to be operated at a constant speed. In another embodiment, the repeated cycles are of short duration. Transient flow conditions result in the tank water which helps avoid dead spaces and assists in agitating the membranes.

Abstract: Disclosed herein are decontamination techniques that use a chemical that acts as an oxygen source and adsorption/binding agent in a UV reactor to bring together organic contaminant molecules and TiO2 molecules in the photoreactive slurry, or to alternatively bind directly to the contaminant molecules if no photocatalyst is employed. In one embodiment, one such system may comprise a contaminated fluid media source providing a contaminated fluid media, which could even be at near-boiling conditions. In addition, the decontamination system may include an adsorption accelerant comprising oxygen and soluble in the fluid media. The adsorption accelerant adsorbing to contaminant molecules in the contaminated fluid media, and should be stable if the fluid media is provided at near-boiling conditions. Also, such a decontamination system may include an irradiation source configured to irradiate the contaminated media containing the adsorption accelerant to eliminate the contaminant molecules from the fluid media.

Abstract: A method for cleaning process apparatus used for production of liquids, especially for cleaning filters, for example membrane filters. The apparatus is contacted with a solution of periodate. It is especially preferred that the cleaning process is carried out at a temperature between 15 and 95° C.

Abstract: This disclosure relates to blood treatment systems and related methods. The systems can include a blood pump arranged to move blood through a blood filter, a pressure sensor arranged to measure pressure of blood flowing through a fluid line between the blood pump and the blood filter, and a controller configured to activate a rinse pump to move rinse fluid through the blood filter based at least in part on the pressure of blood flowing through the fluid line as measured by the pressure sensor.

Abstract: A water filtration system includes a raw water line, a purified water line, and a plurality of water filtration units. The filtration units are connected in parallel between the raw water line and the purified water line. Each of the filtration units has a water filter disposed between and separating a raw water side of the unit connected to the raw water line and a purified water side of the unit connected to the purified water line. The raw water side of each unit has a drain opening. The system furthers includes a plurality of raw water valves each disposed between the raw water line and the raw water side of one of the plurality of units, a plurality of purified water valves each disposed between the purified water line and the purified water side of one of the plurality of units, and a plurality of drain valves each disposed to control flow through the drain opening of one of the plurality of units.

Abstract: A submerged membrane separation apparatus is provided that includes a separation membrane module and fine bubble diffusing tubes placed vertically below the module that can evenly and uniformly produce fine bubbles from vertically below the separation membrane module, even when the separation membrane module is large.

Abstract: A method of cleaning a permeable, hollow membrane (6) in an arrangement of the type wherein a pressure differential is applied across the wall of the permeable, hollow membrane (6) immersed in a liquid suspension provided in a vessel (5), said liquid suspension being applied to the outer surface of the permeable hollow membrane (6) to induce and sustain filtration through the membrane wall. The method of cleaning comprising the steps of: suspending the filtration process; while continuing to supply the liquid suspension to the vessel (5); aerating the membrane (6) by flowing gas into the vessel (5) to produce a flow of gas bubbles around the membrane (6) to dislodge at least some of the retained particulate material from the membrane surface; removing liquid containing dislodged particulate material from the vessel (5) during the aerating step and recommencing the filtration process.

Abstract: The invention relates to a membrane filter for water treatment, comprising a head piece including a permeate collecting chamber with a permeate outlet, and at least one fiber bundle made from capillary membranes, which are secured into the head piece with an end that is open towards the permeate collecting chamber and sealed on the opposite end thereof. The head piece contains an air duct to which the mouth piece that protrudes into the fiber bundle is connected with at least one air outlet. At its other end, the fiber bundle terminates in freely movable manner in the untreated water.

Abstract: A method and device for the cleaning of spiral wound membranes. In the device two or more spiral wound membranes are included in series in pressure tubes. The membranes are cleaned by longitudinal rinsing with water, in which a well-dissolvable gas has been dissolved. In the device for the purification of an aqueous fluid with spiral wound membranes, the membranes can be longitudinal rinsed with water, in which a well-dissolvable gas has been dissolved. As gas that is well-dissolvable preferably CO2 gas or a mixture of gasses is used.

Abstract: A pre-treatment method for cleaning and maintaining reverse osmosis membrane filters by injecting sulfurous acid into waters with suspended solids in a liquid fraction to be filtered to form sulfurous acid (H2SO3) to acid leach heavy metals into the liquid fraction, reduce alkalinity and mineral scaling, add sufficient SO2 as a biocide to attack bacteria and other micro organisms to prevent membrane fouling, reduce iron to prevent iron deposit build-up, scavenge and remove dissolved oxygen prior to filtration to prevent membrane oxidation, and then sequentially filtering the acidified water through membrane filters to create a metal free permeate and a brine retentate, which can be pH adjusted to remove the heavy metals as metal hydroxide precipitates.

Abstract: Dialysis systems comprising actuators that cooperate to perform dialysis functions and sensors that cooperate to monitor dialysis functions are disclosed. According to one aspect, such a hemodialysis system comprises a user interface model layer, a therapy layer, below the user interface model layer, and a machine layer below the therapy layer. The user interface model layer is configured to manage the state of a graphical user interface and receive inputs from a graphical user interface. The therapy layer is configured to run state machines that generate therapy commands based at least in part on the inputs from the graphical user interface. The machine layer is configured to provide commands for the actuators based on the therapy commands.

Abstract: A method for the filtration of a fluid applying a certain preferred setting of one or more process parameters (e.g. a minimal concentration of coagulants) while maintaining desirable process performance by regulating the initial filtration resistance. This is achieved by a feedback controller. Applying the invention on in-line coagulation during membrane filtration has shown, that the initial resistance of the last filtration before the chemical cleaning phase can be controlled within an accuracy of approximately 3% (of the total resistance) or 9% (of the fouling resistance). Compared to current dosing strategy, a significant reduction in coagulant consumption can be achieved.

Abstract: A method of fractionating a dispersion of oxidic nanoparticles wherein at least one step of the method is a membrane crossflow filtration step, the flow of the dispersion over the membrane being brought about by means of driven rotating parts; and dispersions of oxidic nanoparticles that are obtainable by the method.

Abstract: A method for reducing bio-fouling formation on a liquid-contacting surface by pre-designed pretreatment of the liquid with UV light is provided. The method may include flowing liquid through a conduit having ultraviolet-transparent walls; exposing the liquid within the conduit to ultraviolet (UV) light rays from a polychromatic light source that emits in the spectral band of 200 nm to 300 nm and produces effective UV-Dose of above 40 mJ/cm2 such that a portion of the UV light rays is reflected back into the liquid by total internal reflection. After exposure to the UV light, the liquid is contacted the liquid-contacting surface, for example a reverse osmosis membrane without causing biofilm formation.

Abstract: A membrane module (5) comprising a plurality of porous membranes (6), a gas-lift pump apparatus (11) in fluid communication with the module (5) for providing a two-phase gas/liquid flow such that, in use, the two-phase gas/liquid flow moves past the surfaces of the membranes (6) to dislodge fouling materials therefrom. The gas-lift pump device (11) includes: a vertically disposed chamber (12) of predetermined dimensions submersed to a predetermined depth in a liquid medium (15), wherein the chamber (12) has an upper portion (10) in fluid communication with the membrane module (5) and a lower portion (13) in fluid communication with the liquid medium (15); a source of gas (14) in fluid communication with the chamber (12) at a predetermined location therein for flowing gas at a predetermined rate into the chamber (12) to produce the two-phase gas/liquid mixture and to produce a flow of the mixture into the membrane module (5).

Abstract: A process for purification of fluids, for example, desalination of seawater or brackish water, using organic solutes in a concentrated water solution for use in a forward osmosis process, to extract fresh water out of salt water through the forward osmosis membrane, and subsequently separating the organic solutes out of the diluted forward osmosis permeate by cloud point extraction, thereby regenerating a concentrated organic solution for recycling to the forward osmosis process, and fresh water for potable water use.

Abstract: A method cleans a plurality of filters in parallel, each a filter having an inlet side and an outlet side separated by a filter barrier. In an operational phase, water is filtered using a plurality of the filters, by passing the water through the filter, from the inlet side to the outlet side. These filters may be a hollow fiber membrane. In a cleaning phase, at least one of the filters is cleaned while the other filters are filtering water in the operational phase. Each filter is cleaned by supplying sodium hypochlorite to the inlet side of the filter when the filter is off-line. The inlet side of the filter is allowed to soak in the sodium hypochlorite for at least 30 seconds without the sodium hypochlorite being pressurized through the filter barrier during the soaking process. This oxidizes organic contaminates near the surface of the filter. The filters are cycled through the cleaning phase such that each filter is repeatedly cleaned while other filters are filtering in the operational phase.

Abstract: The present invention refers to titanium oxide microspheres having photocatalytic properties which can, for example, be used in a method for cleaning wastewater which uses a submerged membrane reactor.

Abstract: Provided is a cleaning agent or cleaning method of a separation membrane which has cleaning effects equal or superior to those of conventional cleaning methods in cleaning a separation membrane used for filtration of drinking water, industrial water, river water, lake water, groundwater, reservoir water, secondary effluent, waste water, sewage water or the like; does not include a hypochlorite so that it neither generates a toxic gas nor adversely affects the human health; and needs less cleaning time owing to elimination of a rinsing step with a large amount of water. The cleaning agent or cleaning method according to the present invention is therefore safe and economical.

Abstract: A filtration system includes a vessel for housing at least two filtration elements. One or more of the filtration elements is a reverse osmosis membrane or a nanofiltration membrane and one of the other filtration elements is a microfiltration or ultrafiltration membrane. The vessel has an inlet port for providing a liquid feed to the filtration elements, an outlet port for directing a permeate produced by the elements from the vessel and an outlet port for directing a concentrate produced by the elements from the vessel. A number of vessels can be provided in a parallel arrangement and/or a series arrangement and the vessels can be arranged so as to allow regeneration of the microfiltration or ultrationfiltration membranes from another vessel in the arrangement.

Abstract: Method and systems, for processing biological material, that contain a biological material in a vessel; add an aggregating agent to the material in the vessel and allow the material to separate into two or more distinct submaterials; extract one or more of the submaterials from the vessel; automatically transport one or more of the submaterials remaining in the vessel to a filtration device; and collect a resulting target retentate into a target retentate receptacle.

Abstract: A part washing apparatus includes a centrifugal filter and an ultra filter provided as a single base unit. A washing chamber is provided to enclose one or more industrial parts for cleaning with a washing solution, which is collected in a washer bath. The washing solution is then pumped through a centrifugal filter to remove contaminants from the washing solution and subsequently pumped through an ultra filter a filter configured to remove further contaminants from the washing solution.

Abstract: A chamber in which an agent, like genomic DNA, may be harvested and optionally manipulated rapidly (e.g., on the order of a few hours), without shearing or fragmentation.

Abstract: Apparatus and methods are disclosed for mechanical axial vibration in membrane separation treatment processes. The apparatus includes a separation membrane element having an axial dimension, a membrane support structure having the element therein, and means for vibrating the membrane element (hydrodynamically or using motors) in the axial dimension.

Abstract: To provide a method for treating ballast water with a membrane, which can reliably remove a fouling substance derived from a gel-like substance and a fouling substance of mineral origin, the fouling substances attached to a membrane, by separating or breaking down the fouling substances, and can maintain the membrane flux for long periods. In a method for treating ballast water with a membrane, the method provided with, in or on a hull of a ship, the membrane treatment equipment 1 that separates a microorganism with a size equal to or greater than a predetermined size, a fouling substance attached to the surface of the membrane is dissolved, broken down, or removed by using a cleaning fluid containing a peroxide which is at least one selected from hydrogen peroxide, hypochlorous acid, and ozone water.

Abstract: A filtration device is provided for withdrawing permeate essentially continuously from a multicomponent aqueous substrate containing growing microorganisms in a reservoir. A vertical skein of fiber is scrubbed with coarse bubbles which emanate from a conversion baffle positioned under the skein. The substrate is aerated with fine bubbles in a size range small enough to transfer oxygen to the substrate efficiently. The baffle traps the fine bubbles and converts them to coarse bubbles which are effective to scrub the fibers. In the most preferred embodiment, the finished headers of the skein are derived from composite headers comprising a fixing lamina of resin in which the fibers are potted near their terminal ends, and a fugitive lamina of fugitive powdery material in which the terminal ends of the fibers are potted. The fugitive lamina is removed, preferably by dissolving the powder, e.g. finely divided common salt in water.

Abstract: A separation apparatus using a membrane for diafiltration, which provides precise fractionation of a target substance by monitoring and regulating permeability of the target substance based on measurement values and analytical values indicating separation status, such as physical values and concentration of a permeate liquid, a circulating liquid and an internal circulating liquid in a membrane device. A diafiltration process including adding a cleaning liquid to an treating liquid which contains multiple target substances and extracting a target substance into the permeate liquid supplied from a membrane separation apparatus to fractionate the target substance from other target substances remaining in a residual liquid.

Abstract: A method for treating ship ballast water with a membrane, which can easily separate and reliably remove a fouling substance attached to a membrane and maintain the membrane flux for long periods. the method including a membrane separation step of taking in seawater in a port area in which a ship is anchored and separating a microorganism with a size equal to or greater than a predetermined size therefrom with a membrane filtration apparatus installed in or on a hull of the ship and having a filtration membrane module, a backwash step of separating a fouling substance attached to a membrane surface of the membrane filtration apparatus from the membrane surface by backwashing is provided.

Abstract: A method of treating water for municipal use comprises treating the feedwater stream on the feed side of a reverse osmosis membrane with a non-oxidizing, bromine-containing biocide in the substantial absence of a reducing agent, such that biofouling of the membrane is reduced or prevented, and measuring the produced water stream on the permeate side for the presence of bromine-containing compounds. Advantages may include preservation of the membrane, production of water that meets applicable regulations for safe drinking, and simplified processing without additional steps to remove the biocide or its degradation products from the produced water.

Abstract: A method of operating a membrane separator, in which a membrane module comprising a large number of exposed hollow fiber membranes is installed in an untreated water chamber, for making possible stable membrane filtering operation while maintaining a high yield by minimizing loads of the filter membranes and performing effective washing is to be provided, the method including a filtering step at which untreated water is filtered by giving a differential pressure between the primary side (untreated water side) and the secondary side (treated water side) of the hollow fiber membranes, a physical washing step of gas washing by ejecting a gaseous washing medium onto the primary side of the membrane module and of back-pressured water washing by feeding a backwashing medium from the secondary side of the hollow fiber membranes and letting it pass to the untreated water side of the hollow fiber membranes, and a drain step of discharging drain in the chamber out of the system after repeating twice or more the filteri

Abstract: A membrane cleaning apparatus comprising two electrode plates and a filtration unit is provided, wherein the filtration unit is disposed between the electrode plates. The filtration unit comprises a supporting plate and a membrane, and the membrane is disposed on the support plate. This invention can effectively clean the fouling on the membrane by applying an electric field in the membrane region and performing a back flushing process on the membrane. Moreover, a membrane cleaning method is also provided.

Abstract: At the time of loading a ship, ballast water is sent to a ceramic filter membrane having a mesh of 9 to 12 ?m by a filtration pump, and at the time of unloading, ballast seawater is sent to the membrane by the filtration pump to be filtrated under pressure. Thus, marine organisms larger in size than this mesh are removed. The permeated water containing marine organisms smaller in size than the mesh is sterilized with a chemical agent made of chlorine or ozone in a facility for sterilizing with chemical agent, and then discharged into the sea or poured into the ballast tank. With this, it is possible to purify a large amount of ballast water, in a short time, into a level at which the water quality standard according to the guideline can be cleared without requiring any large-sized facility or any high-concentration chemical agent.

Abstract: A method of cleaning a fouled and/or scaled UF or MF membrane with a solution containing one or more thermo-responsive polymers is disclosed. More specifically, the method comprises: (a) treating the membrane in a membrane separation system with a solution containing one or more TRP, wherein said TRP is soluble in said solution and at least an effective amount of said TRP diffuses into a foulant layer that is present on the surface and/or in pores of said membrane; (b) making insoluble said TRP diffused into said foulant layer; (c) optionally rinsing the membrane; (d) optionally backwashing the membrane with air and/or liquid between the steps (b) and (c); and (e) optionally backwashing the membrane with air and/or liquid after the membrane is rinsed in step (c).

Abstract: An apparatus and a method for backwashing filter membrane modules arranged in parallel in the form of a plurality of module rows within a module rack and supplyable with raw water through supply/drain ports at each end face via respectively associated supply/drain lines, and each including a drain port on a wall side for the filtrate, to which a filtrate collection line is connected for draining the filtrate, wherein valve means are provided to control at least one filtration and backwashing mode, wherein, in the backwashing mode, a supply-side control valve of the first supply/drain lines carrying raw water of a module row is closed, but an associated drain-side control valve of the other supply/drain line of one module row serving to drain backwashing water is open, whereas the remaining supply-side control valves in the supply line carrying raw water of the remaining module rows are open, to ensure backwashing of the one module row of the module rack by the filtrate simultaneously produced by the other mod

Abstract: A filtration system for removing fine solids from a liquid suspension comprising a vessel for containing the liquid suspension, one or more permeable, membranes (9) within the vessel, means for providing a pressure differential across walls of the membranes (9) such that some of the liquid suspension passes through the walls of the membranes (9) to be drawn off as permeate and means for withdrawing the permeate from the membranes. A screen (8) is positioned in a flow path of the liquid suspension through to the membrane walls.

Abstract: The present invention generally relates to a filtration system having one or more apparatuses for filtering gases, liquids, or fluids (e.g., water) to remove particulate matter, and methods of making and using the apparatus. More particularly, embodiments relate to apparatuses and methods for applying centrifugal force(s) to push a fluid or gas to be filtered through a porous membrane or filter within the apparatus to separate particulate matter therefrom. The present invention takes advantage of the Coriolis effect within a cylindrical filter radiating out from a rotating central body. The filtration apparatus provides an energy efficient system for microfiltration (or other filtration process) to remove contaminants from gases and fluids, such as waste water.

Abstract: A method of cleaning a fouled or a scaled RO or NF membrane surface with a solution containing one or more thermo-responsive polymers is disclosed. More specifically, the method comprises: treating the membrane surface in a membrane separation system with a solution containing one or more TRP, wherein said TRP is soluble in said solution and at least an effective amount of said TRP diffuses into a foulant layer on said membrane surface; making insoluble said TRP diffused into said foulant layer; optionally, rinsing the membrane.

Abstract: Direct-osmosis (DO) method for cleaning a semi-permeable membrane in a RO separation module, the membrane having a feed side with foulant located thereon, and an opposite permeate side. A normal RO separation process in the same module includes: feeding, under gauge pressure PGr, raw saline solution having osmotic pressure POr to the membrane feed side; collecting permeate (solvent) having osmotic pressure POp from the permeate side, under gauge pressure PGp; and removing residual brine from the membrane feed side. The method comprises feeding to the feed side of the membrane, for a predetermined injection time, super saline solution having osmotic pressure POs>POr, such that backward flow of permeate towards the feed side of the membrane is provided so as to lift the foulant from the feed side.

Abstract: An aeration system for a submerged membrane module has a set of aerators connected to an air blower, valves and a controller adapted to alternately provide a higher rate or air flow and a lower rate of air flow in repeated cycles. In an embodiment, the air blower, valves and controller, simultaneously provide the alternating air flow to two or more sets of aerators such that the total air flow is constant, allowing the blower to be operated at a constant speed. In another embodiment, the repeated cycles are of short duration. Transient flow conditions result in the tank water which helps avoid dead spaces and assists in agitating the membranes.

Abstract: A method for cleaning and maintaining reverse osmosis membrane filters by injecting sulfurous acid into water to form sulfurous acid (H2SO3), and then sequentially filtering the acidified water through membrane filters to reduce alkalinity and mineral scaling, add sufficient SO2 as a biocide to attack bacteria and other micro organisms to prevent membrane fouling, reduce iron to prevent iron deposit build-up, scavenge and remove dissolved oxygen prior to filtration to prevent membrane oxidation, and prevent concentrated salts within the retentate from precipitating out of solution during transport for land application.

Abstract: A membrane filtration system (5) including: a feed containing vessel (7); a membrane module (6) including one or more hollow permeable membranes (8) for filtering feed liquid, located in the feed containing vessel (7); means for applying a pressure differential across walls of the membranes (8) to induce filtration therethrough; a feed liquid reservoir (9) in fluid communication with the membrane module (6) to supply feed liquid thereto; a source of feed liquid (12); a source of gas (10) and means (11) for selectively producing a flow of gas from the gas source (10) and feed liquid from the feed liquid source (12) through the membrane module (6) and into the feed liquid reservoir (9). The flow of gas producing gas bubbles within the feed liquid to clean the membranes (8).

Abstract: The present invention is in relation to an apparatus for purification of blood and a method for assembling such apparatus. Also, the invention provides solution to the problem of kidney damage, wherein the damaged kidney can be replaced with the apparatus of instant invention to help in the purification of blood and thus helps the patients at large having kidney related disorders.

Abstract: A method of cleaning a membrane (6) in a membrane filtration system by flowing gas bubbles past the surfaces of the membrane (6) to scour accumulated solids therefrom. The method includes flowing a liquid past a supply of gas; creating a reduced pressure within the liquid flow to cause a flow of gas from the supply of gas (9) into the liquid flow and form gas bubbles therein and then flowing the liquid containing the gas bubbles past the surfaces of the membrane (6) to scour the surfaces thereof. Apparatus for performing the method is also disclosed.