Definitions

• TITLE APPARATUS AND METHOD FOR CLEANING MEMBRANE FILTRATION
• membrane bioreactors combining biological and
• membrane bioreactors can range from household (such as
• backwash backpulse, backflush
• membrane surface scrubbing or scouring using a gas in the form of bubbles in a liquid.
• a gas is injected, usually by means of a pressurised
• the bubbles so formed then travel upwards to scrub the membrane surface to remove the
• the gas distribution system may gradually become blocked by dehydrated solids or simply
• membrane module as used herein is defined as the cross-sectional potted area taken up by
• the present invention seeks to overcome or least
• the present invention provides a method of scrubbing a
• membrane surface using a liquid medium with gas bubbles entrained therein including the
• the gas bubbles are entrained into said liquid stream by means of a
• venturi device for further preference, the gas bubbles are entrained or injected into said
• mixture of liquid and bubbles such devices including a jet, nozzle, ejector, eductor, injector or the like.
• an additional source of bubbles may be provided in said
• the gas used may include air, oxygen,
• Gaseous chlorine may be used for scrubbing, disinfection and enhancing
• the present invention provides a membrane module
• said liquid and bubbles are mixed and then flowed past membranes to
• the present invention provides a method of
• membranes mounted and extending longitudinally in an array to form a membrane module
• said membranes being arranged in close proximity to one another and mounted to prevent
• the method comprising the steps of providing, from
• said bubbles are injected and mixed into said
• the membranes comprise porous hollow fibres, the fibres being fixed
• the lower header having one or more holes formed therein through
• the holes can be circular, elliptical or in the form of a
• the fibres are normally sealed at the lower end and open at their upper end to allow
• the fibres may be open at both ends to
• the fibres are preferably arranged in
• the present invention provides a membrane module
• fibre membranes comprising a plurality of porous hollow fibre membranes, said fibre membranes being
• fibre membranes being fixed at each end in a header, one header having
• partition means extending at least part way between said headers to partition said
• the partition means are formed by a spacing
• the partitions may be parallel to each other or, in the
• the partitions may extend radially from the centre of the array or be positioned concentrically within the cylindrical array.
• the fibre bundle may be provided with a central longitudinal passage
• the present invention provides a membrane module
• a membrane bioreactor including a plurality of porous hollow membrane fibres
• said membrane fibres being arranged in close proximity to one another and mounted to
• fibres being partitioned into a number of
• one of said potting heads having an array of aeration openings formed
• the fibre bundle is protected and fibre movement is limited by a module support
• said aeration openings are positioned to coincide with the spaces formed
• said openings comprise a slot, slots or a
• the fibre bundles are located in the potting head between the slots
• gas bubbles are entrained or mixed with a liquid flow
• the liquid used may be the feed to the membrane module.
• the fibres and/or fibre bundles may cross over one another between the potting heads though it is desirable that they do not.
• the fibres within the module have a packing density (as defined above) of
• said holes have a diameter in the range of about 1 to 40 mm and more
• the open area is chosen to be equivalent to that of the above holes.
• the fibre inner diameter ranges from about 0.1 mm to about 5 mm and is
• the fibres wall thickness is
• wall thickness is between 0.05 to 2 mm and more often between 0.1 mm to 1 mm.
• the present invention provides a membrane bioreactor
• the present invention provides a method of
• the membrane fibres to dislodge fouling materials therefrom.
• the gas bubbles Preferably, the gas bubbles
• a further source of aeration may be provided within the tank to assist microorganism activity.
• the membrane module is suspended vertically
• the further source of aeration comprises a group of air permeable
• the membrane module may be operated with or without backwash depending on
• partitioned fibre bundles enables higher packing densities to be achieved without
• Figure 1 shows a schematic side elevation of one embodiment of a membrane
• Figure 2 shows an enlarged schematic side elevation of one form of the jet type
• Figure 3a shows a schematic side elevation of a partitioned membrane module
• Figure 3b shows a section through the membrane bundle of Figure 3a
• Figure 4a shows a schematic side elevation of a partitioned membrane module according to a further embodiment of the present invention
• Figure 4b shows a section through the membrane bundle of Figure 4a
• Figure 5a shows a schematic side elevation of a partitioned membrane module
• Figure 5b shows a section through the membrane bundle of Figure 5a
• Figure 6a shows a schematic side elevation of a partitioned membrane module
• Figure 6b shows a section through the membrane bundle of Figure 6a
• Figure 7 shows a similar view to Figure 2 of a further embodiment of the invention.
• Figure 8 shows a similar view to Figure 2 of yet a further embodiment of the
• Figure 9 shows a sectioned perspective pictorial view of the lower end of another
• Figure 10 shows a sectioned perspective pictorial view of the upper end of the
• the membrane module 5 typically comprises fibre, tubular or flat sheet form membranes 6
• Either one or both ends of the membranes may be used for the permeate collection.
• the bottom of the membrane module has a number of through apertures 10 in the pot 11 to
• a venturi device 12 or the like is
• the venturi device 12 intakes gas through inlet 13,
• liquid feed or the gas can be a liquid feed or the gas
• venturi device 12 can be a venturi tube, jet, nozzle, ejector, eductor, injector or the like.
• liquid is forced through a jet 16 having a surrounding air passage 17 to
• the liquid commonly used to entrain the gas is the feed water, wastewater or mixed
• a vacuum to suck the gas into the liquid, or reduces the gas discharge pressure when a
• blower is used. By providing the gas in a flow of the liquid, the possibility of blockage of
• the distribution apertures 10 is substantially reduced.
• distribution device can eliminate the formation of dehydrated solids and therefore prevent
• the injection arrangement further provides an efficient cleaning mechanism for
• the module configuration described allows a higher fibre packing density in a
• membrane modules can be either integrated into the aerobic basin or arranged in a
• process fluid often enters one end of the tank and concentrates as it moves across the
• Such a cleaning method can be used to the treatment of drinking water, wastewater
• the filtration process can be driven by suction or
• FIG. 3 shows a bundle of tubular membranes 20 partitioned vertically into several
• Another method of forming a partitioned module is to pot
• central membrane-free zone forms a passage 24 to allow for more air and liquid injection.
• a single gas or a mixture of gas/liquid can be injected into the module.
• Figure 6 illustrates yet a further embodiment similar to Figure 5 but with single
• fibre membranes 20 are spread adjacent the hole 30 and
• FIGS. 7 and 8 show further embodiments of the invention having a similar
• the module 45 comprises a plurality of
• hollow fibre membrane bundles 46 mounted in and extending between an upper 47 and
• the potting heads 47 and 48 are mounted in respective potting
• bundles 46 are surrounded by a screen 51 to prevent excessive movement between the
• the lower potting head 48 is provided with a number of
• the aeration holes 52 are positioned to generally coincide with the partition
• the lower potting sleeve 50 forms a cavity 55 below the lower pot 48.
• Air is preferably introduced into the module continuously to provide oxygen for
• filtrate is drawn out of the membranes by a suction pump attached to the membrane lumens
• the membrane module is operated under low transmembrane pressure
• TMP suspended solids
• the membrane bioreactor is preferably combined with an anaerobic process which

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• Separation Using Semi-Permeable Membranes (AREA)

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• 1999
  • 1999-09-24 EP EP99948614A patent/EP1115474A4/de not_active Ceased

Patent Citations (3)

Non-Patent Citations (10)

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