Membrane bioreactor module

Abstract

The present invention provides a membrane bioreactor module comprising a base member and an upper assembly between which an array of fibrous membranes extends, the module further comprising four corner supports or posts extending between the base assembly and the upper assembly, at least one of these corner supports or posts defines an internal fluid passage from the base assembly to the upper assembly to facilitate removal of permeate from the base assembly.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority under 35 USC §365(c) to U.S. Provisional Application No. 63 / 341,241, filed on May 12, 2022, the entire contents of which are incorporated herein. Technical Field

[0003] The present invention relates to a membrane bioreactor module, in particular a module defining novel fluid filtrate passages and means of sealing the upper and lower ends of the module to the body of the module. Background Art

[0004] Several patents, patent applications and publications are cited in this specification to more fully describe the state of the art to which the present invention relates. The entire disclosure of each of these patents, patent applications and publications is incorporated herein by reference.

[0005] The use of membrane bioreactors (MBR) to achieve filtration of wastewater and the like is well known. See, for example, Judd, Simon and Judd, Claire, eds. The MBR Book , Elsevier Science (2006); and the Water Environment Federation Membrane Systems for Wastewater Treatment [ use Membrane systems for wastewater treatment ], McGraw Hill Professional (2005). Such MBR systems are typically composed of a plurality of fiber modules, each of which includes a large array of hollow fiber membranes captured between a base and an upper assembly, through which the effluent to be treated can be drawn through the fibers to achieve filtration. The racks of these modules are immersed in the main treatment tank and are therefore exposed to the wastewater or other effluent to be treated.

[0006] Microfibers are usually potted into a base and an upper component, wherein the upper and / or lower end of each microfiber is communicated with a sealed internal space defined in the corresponding component. In this way, the fluid can be driven under a positive or negative pressure difference, such as via a pump, etc., through the side wall of the fiber from the main treatment tank, and enter the base and / or upper component along the length of the fiber for continued treatment or extraction. This is generally referred to as the "outside-to-inside" flow direction, in which solid pollutants are deposited on the outer surface of the fiber membrane, which can then be processed in a variety of different ways. This MBR system can be a so-called "single" head or "double" head system, in which the inner cavity of each of the potting fibers is communicated with the upper and / or lower components for removing permeate from the fiber. As used herein, the term "inner cavity" refers to the hole of the tubular structure, for example, refers to the internal passage of the hollow fiber membrane. These fiber membranes can be formed by many different materials, typically hydrophilic polymers or polymer blends, such as PVDF. These fiber membranes are also manufactured to have a pore size suitable for specific filtration applications.

[0007] Some MBR systems are operable to reverse the direction of flow in order to flush solid contaminants from the outer surfaces of the fiber membranes, whereupon the solids can be deposited and removed for treatment. Additionally or alternatively, the MBR system may include some form of air flushing to remove contaminants from the outer surfaces of the fiber membranes for subsequent treatment, such as sludge removal and drying. Additional upstream and / or downstream processing steps will typically be implemented within the wastewater treatment plant.

[0008] Such MBR systems have many advantages, including consistent treated water quality and high retention efficiency of organic components, solids, and microorganisms. MBR systems typically have a relatively small footprint, typically do not require settling tanks or sand filters, and are modular in construction, allowing facility expansion as needed. MBR systems do not encounter sludge "bulking" or sedimentation problems, are typically able to handle sudden changes in flow, have reduced sludge yields, are highly automated, and have decreasing operating energy costs.

[0009] In an MBR, the higher the fiber density within each reactor and therefore within each module, the greater the filtration capacity because more membrane surface area is available for removal of solids and / or other contaminants. It is therefore beneficial to increase the fiber density for a reactor module of a given size or footprint while ensuring the reliability and longevity of these modules to ensure consistent treatment over an extended period of operation, which in the case of a municipal wastewater treatment plant, desalination plant, etc., may be decades of operation.

[0010] It is therefore an object of the present invention to provide a membrane bioreactor module having an increased fiber density for a given module footprint while minimizing design and manufacturing complexity in order to produce a low-cost and reliable component. Summary of the invention

[0011] Therefore, the present invention provides a membrane bioreactor module, which includes: a base assembly, an upper assembly, and a hollow fiber membrane array extending between the base assembly and the upper assembly; a plurality of support members extending between the base assembly and the upper assembly, at least one of the support members being hollow so as to define a fluid flow path between the base assembly and the upper assembly; wherein the upper assembly includes: an anchor plate having an upper face and a lower face, and one end of each of the support members is fixed to the lower face via the lower face of the anchor plate; a plurality of connectors located in the anchor plate, each of the plurality of connectors defining a socket opening on the lower face and retaining an end of a corresponding hollow support member; and at least one pipe extending laterally from the socket and opening on the upper face.

[0012] Preferably, the anchor plate defines at least one enclosure filled with a potting resin to secure the hollow fiber membranes to the anchor plate.

[0013] Preferably, each duct extends through the potting resin.

[0014] Preferably, each duct opens on the upper face adjacent to a respective fastener.

[0015] Preferably, the potting resin defines an upper face of the anchor sheet.

[0016] Preferably, each duct is defined by an insert secured to the anchor plate.

[0017] Preferably, the socket is integrally formed with the anchor plate.

[0018] Preferably, the socket defines an open lower end, a closed upper end, and a lateral window through which the conduit extends.

[0019] Preferably, the hollow support member is bonded into the socket.

[0020] Preferably, the hollow support member is bonded into the base assembly.

[0021] Preferably, the membrane bioreactor module comprises a manifold mounted to the upper face of the anchor plate for establishing fluid communication with the bioreactor module.

[0022] Preferably, each coupling includes a fastener axially aligned with the socket and accessible at the upper face for securing the manifold to the anchor plate.

[0023] Preferably, the fastener comprises a threaded insert secured to the anchor plate and having threads, the longitudinal axis of the threaded insert being coaxial with the longitudinal axis of the support member and the socket.

[0024] Preferably, the manifold is fixed, more preferably bolted, to the anchor plate.

[0025] Preferably, the manifold includes a respective lug having a through hole overlying each fastener when the manifold is aligned against the upper face of the anchor plate.

[0026] Preferably, the membrane bioreactor module is substantially rectangular in cross-section and four support members are provided, one at each corner.

[0027] Preferably, one or more of the support members are hollow and define respective fluid flow paths between the base assembly and the upper assembly.

[0028] Preferably, the manifold defines a fluid permeate conduit in fluid communication with the at least one conduit, and a separate air supply conduit for delivering air to the base assembly.

[0029] Preferably, the membrane bioreactor module comprises a gasket captured between the manifold and the anchor plate.

[0030] Preferably, the base assembly comprises at least one enclosure filled with a potting resin to secure the hollow fiber membranes to the base assembly in a manner allowing fluid communication between the lumen of each fiber and the chamber of the base assembly.

[0031] Preferably, the membrane bioreactor module comprises an air flush system mounted to the base assembly.

[0032] Preferably, the air flushing system is operable to produce a pulsed release of air to flush the hollow fibers.

[0033] Preferably, the membrane bioreactor comprises a gas supply line extending from the manifold to the air flush system for delivering air from the manifold to the air flush system.

[0034] Preferably, the membrane bioreactor module comprises a gasket disposed between each support and the socket to establish and maintain a fluid-tight interface therebetween.

[0035] Preferably, the gasket comprises an elastically deformable seal and / or an adhesive seal.

[0036] According to another aspect of the present invention, a fiber membrane assembly for a membrane bioreactor is provided, the fiber membrane assembly comprising: a frame, preferably a rectangular frame, the frame defining at least one enclosure extending between a first side of the frame and a second side opposite to the frame; at least one channel, the at least one channel providing fluid communication between the first side and the second side; a filtrate enclosure located around the first side of the frame and defining a chamber therein, the channel extending through the filtrate enclosure and isolated from the chamber; and a fiber membrane array, the free end of each fiber membrane in the fiber membrane array being encapsulated in a potting compound that fills and seals the enclosure, wherein the inner cavity of each fiber membrane is fluidly connected to the chamber.

[0037] The advantages and features of novelty which characterize the invention are particularly pointed out in the appended claims and form a part thereof. However, for a better understanding of the invention, its advantages and objects attained by its use, reference should be made to the drawings forming a further part hereof and to the accompanying descriptive matter, in which one or more preferred embodiments of the invention are shown and described. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will now be described with reference to the accompanying drawings, in which:

[0039] Figure 1 A perspective view of a membrane bioreactor module according to a preferred embodiment of the present invention is shown;

[0040] Figure 2 Shown Figure 1 An enlarged view of the upper assembly of the membrane bioreactor module is shown;

[0041] Figure 3 Shown Figure 1 An enlarged view of the base assembly of the membrane bioreactor module is shown;

[0042] Figure 4 Shown Figure 2 a cross-sectional view of a corner of an upper assembly of a membrane bioreactor module illustrated and showing the internal flow path defined therein; and

[0043] Figure 5 Shown Figure 3 a cross-sectional view of a lower corner of a base assembly of a membrane bioreactor module illustrated and showing an internal flow path defined therein;

[0044] Figure 6 showing a cutaway side elevation view through a center portion of the base assembly;

[0045] Figure 7 showing a cut-away side elevation view through a pair of opposing corners of a base assembly, including a corresponding pair of opposing support members;

[0046] Figure 8 shows a top plan view of a potting frame forming part of a base assembly;

[0047] Fig. 9 Shown Fig.10 A sectional side elevation view of the potting frame taken along line AA;

[0048] Fig.10 Shown Fig.11 An enlarged view of detail B in FIG.

[0049] Fig.11 showing a top plan view of a filtrate enclosure forming part of the base assembly and, in use, secured to the underside of the potting frame;

[0050] Fig.12 Shown Fig.11 A sectional side elevation view of the filtrate enclosure;

[0051] Fig.13 showing a plan view of an annular seal disposed between the support and base assemblies to provide a fluid-tight seal between the support and base assemblies; and

[0052] Fig.14 Shown Fig.13 A cross-sectional view of the annular seal is shown taken along line AA. DETAILED DESCRIPTION

[0053] Reference is now made to the drawings, wherein like reference numerals designate corresponding structures throughout the several views, and in particular to Figure 1 , shows a membrane bioreactor module 10 according to a preferred embodiment of the present invention, which membrane bioreactor module is used to be deployed in a wastewater treatment plant (not shown) or the like, wherein a plurality of bioreactor modules 10 are arranged in one or more arrays, which are selected to provide the necessary treatment / filtration requirements matched to a particular hydraulic load. The module 10 is located in a treatment tank (not shown) and is immersed in wastewater when in use to achieve treatment of the wastewater, as is well known in the art, so that the operation of the module does not need to be explained in detail. See, for example, the above-referenced MBR Guide and Membrane systems for wastewater treatment However, unlike the prior art, the bioreactor module 10 of the present invention provides a novel fluid flow path for permeate through the module 10, which allows the bioreactor module 10 to contain a higher fiber density, thereby achieving a higher filtration capacity through increased fiber surface area, while being easier and more cost-effective to manufacture and having increased reliability during operation.

[0054] Still reference Figure 1The membrane bioreactor module 10 includes a base assembly 12, an upper assembly 14 spaced a suitable distance from the base assembly 12, and an array of hollow fiber membranes 16 fixed between the base assembly 12 and the upper assembly 14 as described above. The fiber membrane 16 (which can be a microfiltration membrane or an ultrafiltration membrane) can have any suitable size (including length, outer diameter, and inner cavity diameter) and can include any suitable material with desired properties such as porosity, density, etc. Suitable materials include but are not limited to the above-cited MBR Guide and Membrane systems for wastewater treatment The materials described in and Yoon, Seong-Hoon Membrane Bioreactor Processes-Principles and Applications Theory and Application ], Taylor & Francis eBooks (2016), first edition, CRC Press (Boca Raton, 2015) on page 71 of Table 2.3. Preferred materials include, but are not limited to, PES, PS, PTFE, HFP, polyolefins (e.g., PP, PE), PVC, PAN, polyimides, polyamides, and ceramics. PVDF and PVDF blends are more preferred. For example, the fiber membrane 16 may comprise polyvinylidene fluoride (PVDF) having a pore size of 0.04 μm to achieve so-called ultrafiltration, although any other pore size and / or material may be used, particularly intended to be suitable for the intended application of the bioreactor module 10. In an exemplary embodiment, the fiber membrane 16 is about 1.6 meters in length, wherein in such an exemplary bioreactor module 10, the entire bundle of fiber membranes 16 defines 40 m. 2 In the drawings, the fiber membranes 16 are schematically shown in the form of blocks, representing individual fiber membranes 16 in bundles.

[0055] Because the fiber membrane 16 is typically flexible and therefore does not provide any meaningful structural integrity, the bioreactor module 10 includes at least one (four in the preferred embodiment shown) rigid elongated support members 18 extending between the base assembly 12 and the upper assembly 14 to fix the assemblies 12, 14 relative to each other. In the preferred embodiment shown, the bioreactor module 10 has a generally rectangular footprint or cross-section and includes a support member 18 at each corner. However, it will be understood from the following description of the operation of the present invention that alternative configurations may be employed while retaining the novel functions described herein.

[0056] The base assembly 12 and the upper assembly 14 may be formed of any suitable material or combination of materials and are most preferably molded from a suitable polymer or the like. Suitable materials include, but are not limited to, polyamide, ABS, PVC, acetal, PPO, and PPE (such as Noryl available from Sabic Corp. of Saudi Arabia).TM Resin) and PP. Blends of polyamide in powder or fiber form with inorganic fillers (such as glass-filled polyamide) are preferred. Similarly, the support members 18 can be formed of any suitable material (such as FRP (polyester or vinyl ester), SS and PVC) and can be appropriately sized to provide the necessary structural strength to the bioreactor module 10. At least one of the supports 18, and preferably all of the supports, is hollow so as to define a fluid flow path between the base assembly 12 and the upper assembly 14 in these supports, thereby allowing permeate to be transported from the base assembly 12 to the upper assembly 14 without any additional hardware to provide this flow path. Therefore, the support members 18 serve the dual purpose of defining both structural components and fluid distribution passages. In this way, the bioreactor module 10 is operable to extract permeate from the base assembly 12 and optionally also from the upper assembly 14, as will be described.

[0057] Special References Figure 2 and Figure 4 , the upper assembly 14 includes an anchor plate 20 to which the upper ends of the fiber membranes 16 and the upper ends of each of the supports 18 are secured. The upper assembly 14 further includes a manifold 22 mounted in sealing engagement against the upper face of the anchor plate 20 and adapted to extract permeate from the module 10 and supply air to the module 10, as described in further detail below. The anchor plate 20 preferably has a generally rectangular footprint and defines an enclosure 24 in which the upper end of each fiber membrane 16 is preferably positioned and secured during manufacture by means of a potting resin 26 that is poured to fill the enclosure 24 and thereby encapsulate the ends of each of the fiber membranes 16. The upper ends of the fiber membranes 16 may be sealed within the potting resin so as to enclose the upper ends of the fiber membranes 16, whereby permeate may only be drawn from the interior of the fiber membranes 16 into the base assembly 12. Alternatively, the upper ends of the fiber membranes 16 may be exposed or otherwise in fluid communication with the upper face of the anchor plate 20 as defined by the upper surface of the potting resin 26, thereby allowing fluid to flow from within each fiber membrane 16 into the interior enclosure 24 of the manifold 22. Such methods of securing the fiber membranes 16 are well known in the art, and further details regarding such methods are not necessary or relevant for a complete understanding of the present invention. However, it should be noted that any other functional alternative means of anchoring or securing the fibers 16 to the anchor plate 20 may also be employed.

[0058] Still reference Figure 2 and Figure 4, each corner of the anchor plate 20 includes a coupling 28 which functions to secure the respective support 18, the anchor plate 20 and the manifold 22 together, while establishing a fluid flow path from the interior of the support 18 into the interior of the manifold 22 to allow permeate to be extracted from the base assembly 12 through the support 18 and into the manifold 22 for removal from the module 10. By providing such a fluid flow path through the corner support 18, it is not necessary to provide a separate flow path, thereby reducing complexity and effectively increasing the footprint of the module 10 that can be occupied by the fiber membranes 16, thereby increasing the processing capacity of the module 10. The coupling 28 includes a socket 30 that is open on the lower face of the anchor plate 20 and is sized to receive the upper end of the respective support 18. Thus, in the case of a cylindrical support 18 as in the illustrated embodiment, the socket 30 has a cylindrical cross-section and has a diameter approximately equal to the outer diameter of the support 18 at least at the upper portion of the socket 30. However, the socket 30 may include a number of longitudinally extending and radially spaced webs or tabs (not shown) that are used to define a space between the socket 30 and the outer surface of the support member 18, and a suitable adhesive may be applied to the space to provide a strong and fluid-tight seal between the socket and the outer surface of the support member.

[0059] The socket 30 also preferably defines at least a portion of an external passage 31 adjacent to the lower or open end of the socket 30, into which a sealant and / or adhesive may again be applied to further secure and seal the support 18 in place. Thus, in use, a fluid-tight seal is established between the socket 30 and the support 18, which may be achieved in addition or alternatively by means of an interference fit between the parts, and / or by providing a suitable sealant or adhesive as described above and / or a gasket or similar hydraulic seal and / or by providing complementary threads on the outer surface of the support 18 and the inner surface of the socket 30 (fluid-tight seal not shown).

[0060] Still reference Figure 2 and Figure 4 Socket 30 includes a shoulder 32 of reduced diameter toward the upper end of socket 30 against which the upper end of support 18 abuts when support 18 is fully seated within socket 30. Socket 30, however, extends beyond shoulder 32 to terminate at a blind upper end 34, although a lateral hole 36 is provided between shoulder 32 and upper end 34. Lateral hole 36 leads to a conduit 38 that extends upwardly until terminating at an outlet 40 located in the upper face of anchor plate 20, thereby providing a fluid flow path into the interior of manifold 22.

[0061] The conduit 38 may be defined by a molded insert captured within the potting resin 26, although any other suitable alternatives may be used, such as molding the conduit 38 integrally with the anchor plate 20. The fluid flow path of the permeate as defined by the interior of the support 18 and the conduit 38 is defined by Figure 4 The arrows provided in the display.

[0062] Still reference Figure 2 and Figure 4 , the coupling 28 further includes a fastener, which may take any suitable form, such as in the illustrated embodiment in the form of a threaded insert 42 secured to or integrally formed with the anchor plate 20, directly above and axially or longitudinally aligned with the socket 30 and, therefore, the support member 18, but isolated from the socket 30 such that fluid flowing into the socket 30 enters the conduit 38 entirely via the lateral aperture 36. The threaded insert 42 is accessible from the upper face of the corner of the anchor plate 20 to receive a fastening member, such as a bolt (not shown), through a corner lug 44 of the manifold 22, thereby securing the manifold 22 in face-to-face engagement with the upper face of the anchor plate 20. By axially or longitudinally aligning the threaded insert 42 with the support member 18, the support member 18 provides sufficient load-bearing capacity to allow the manifold 22 to be tightly clamped to the anchor plate 20, thereby establishing a fluid-tight seal between the manifold and the anchor plate. The threaded insert 42 may be any suitable material, such as a metal or polymer, having suitable physical properties to provide the necessary grip and retention to a bolt (not shown) or other fastening member.

[0063] It will be appreciated that the threaded insert 42 may be omitted and that the manifold 22 may be secured to the anchor plate 20 using, for example, self-tapping screws (not shown) which are screwed directly into the material of the anchor plate 20 where the insert 42 is omitted. Any other functional alternatives may of course be employed, but it has been found that the threaded insert 42 provides a secure, strong and reliable connection. In a preferred arrangement, a gasket (not shown) is provided at the interface between the anchor plate 20 and the manifold 22 in order to ensure and maintain a fluid-tight seal between the anchor plate and the manifold. An externalizing channel 45 is provided in the upper face of the anchor plate 20 for receiving and retaining the gasket (not shown). This arrangement provides a robust overall construction to ensure reliability under the relatively harsh operating conditions to which the module 10 may be subjected during its lifetime.

[0064] Manifold 22 includes a fluid permeate conduit 46 that opens to the interior of manifold 22 and is therefore in direct fluid communication with the upper face of anchor sheet 20, as may be seen, for example, at Figure 24, wherein one of the outlets 40 can be considered to be in direct communication with the permeate conduit 46. As described above, the manifold 22 includes four corner lugs 44, each of which has a through hole to allow the manifold 22 to be bolted or otherwise fastened to the anchor plate 20 and thus to the base assembly 12 via the support 18. The manifold 22 further includes an air conduit 48 isolated from the permeate conduit 46, the purpose of which is described in detail below. Any other suitable location or configuration of the air conduit may be employed. The manifold 22 is preferably formed as a single molded piece, wherein the permeate conduit 46 and the air conduit 48 are thus integrally molded with each other, although other configurations may be utilized as well.

[0065] Reference now Figure 5 , the corners of the base assembly 12 are shown in cross-section, thereby revealing the connection between the lower end of the support member 18 and the base assembly 12. Each corner of the base assembly 12 defines a socket 50 that is shaped and sized to receive the support member 18, wherein a reduced diameter shoulder 52 is located inside the socket 50 to provide an abutment against which the end of the support member 18 engages. Although it is preferred that an adhesive or the like be provided between the socket 50 and the support member 18, it is also preferred that a seal 54 be provided to ensure that a hydraulic seal is maintained even in the event of adhesive failure. The seal 54 is provided at Fig.13 and Fig.14 50 and preferably in the form of an annular seal having a square or rectangular cross-section and preferably having a skirt 55 at its lower end. The use of this particular configuration of seal reduces the force required to insert each of the supports 18 into the socket 50 during manufacture of the bioreactor module 10, thereby allowing all four supports 18 to be pressed into the socket 50 at the same time. If conventional O-rings were employed, this would not be possible or practical because the force compressing the rubber O-rings at all four corners would be significant and therefore the frame would become unstable during compression. In addition, the use of conventional rubber lubricants is generally not practical because these materials typically result in contamination of the potting resin. Of course, it will be understood that additional and / or alternative ways of sealing the socket 50 and the supports 18 may be utilized, for example an adhesive may be provided in the socket 50 to further seal the lower end of the support 18 to the base assembly 12. It will be understood that additional hydraulic seals may be used to seal the supports 18 to Figure 4 An alternative or additional method for the upper anchor plate 20 and the socket 30 in the embodiment of the present invention is provided. Figure 4 It will be further understood that the same advantages of the additional seal may also be applied to the end of the support 18 that is attached to the upper assembly 14 of the module.

[0066] refer to Figure 3 and Figure 5, the base assembly 12 preferably has a generally rectangular footprint and defines a slot or cavity 56. The terms "slot" and "cavity" are synonymous and are used interchangeably herein with respect to feature 56 of the potting frame 60. During manufacturing, the lower end of each fiber membrane 16 is preferably positioned and secured in the slot or cavity 56 by means of a potting resin (not shown) that is poured to fill the slot or cavity 56 and thereby encapsulate the lower end of each of the fiber membranes 16. Figure 8 As depicted, the grooves or enclosures 56 may be in fluid communication. Alternatively, each may form a separate closed receptacle for potting resin.

[0067] The lumen of each of the fiber membranes 16 is in fluid communication with a chamber 58 located directly below the enclosure 56. The chamber 58 extends below each of the sockets 50 and is in fluid communication with the sockets. The chamber 58 is otherwise sealed from the exterior of the module 10. Thus, permeate drawn into the interior of the fiber membranes 16 can be drawn into the chamber 58, upward within the interior of the hollow support 18 and into the permeate conduit 46 defined within the manifold 22 for extraction from the module 10. The fluid flow path of the permeate defined by the chamber 58 and the interior of the support 18 is defined by Figure 5 The arrows provided in the figure are shown.

[0068] Special References Figures 6 to 12, the base assembly 12 preferably includes a potting frame 60 and a filtrate enclosure 62, the potting frame defining a plurality of enclosures 56, the filtrate enclosures being secured around and sealed to the lower face of the potting frame 60 so as to completely enclose the lower face thereof and thereby define chambers 58. In the illustrated embodiment, six parallel enclosures 56 are provided in the potting frame 60, but the number and configuration thereof may vary. Thus, the chambers 58 within the filtrate enclosure 62 define six parallel segments corresponding to the enclosures 56 so as to allow filtrate to be drawn from the open end of each of the fiber membranes 16 into the chambers 58 for transfer through the support 18. The filtrate enclosures 62 may be secured to the potting frame 60 in any suitable manner to form a fluid-tight seal at their interface. The fiber membranes 16 are preferably grouped together in the enclosures 56 and arranged to provide spaces between the enclosures 56 with a number of openings or passages 64 extending upwardly through both the potting frame 60 and the filtrate enclosure 62 of the base assembly 12 to allow airflow upwardly through the base assembly 12, as described in detail below. These openings or passages 64 do not communicate with the interior of the chamber 58 or the enclosure 56, and simply provide a passage through the base assembly 12 via which flushing air can pass upwardly through the base assembly from the underside of the base assembly 12 to contact the outer surface of the fiber membranes 16. Seals 66 are preferably provided around the interface of the passages 64 to ensure a fluid-tight seal at the interface between the potting frame 60 and the filtrate enclosure 62. The seals 66 may be integrally formed with the potting frame 60 and / or the filtrate enclosure 62, for example by means of overmolding. Alternatively, other suitable sealing means, such as gaskets, may be employed.

[0069] The fiber membranes 16 are fixed in each of the enclosures 56 with a potting resin or functional equivalent, which fills the space between the fiber membranes 16 and thus forms a seal around each of the fiber membranes 16 and between the side walls of the enclosures 56, thereby preventing fluid from flowing through the enclosures 56 instead of through the inner lumen of each of the fiber membranes 16. The fiber membranes 16 extend upwardly from the enclosures 56 to the upper assembly 14. The free lower end of each of the fiber membranes 16 is open to the lower face of the potting frame 60 and is therefore in communication with the chamber 58 within the filtrate enclosure 62. In this way, filtrate can be drawn from the fiber membranes 16 into the chamber 58. Although the chamber 58 is divided into sections corresponding to the enclosures 56 of the potting frame 60, these sections are preferably in fluid communication with each other, and each corner of the chamber 58 is in fluid communication with the free lower end of the corresponding support 18.

[0070] In a preferred manufacturing method, a bundle of fiber membranes 16 is inserted into each of the enclosures 56, wherein one free end of each of the fiber membranes 16 protrudes from the lower side of the enclosure 56, a short distance beyond the lower face of the potting frame 60. The enclosures 56 are then filled with a potting resin or the like so as to bond the fiber membranes 16 to the potting frame 60. The potting resin is also allowed to extend beyond the lower face of the potting frame 60 to encapsulate the protruding fiber membranes 16. Once the potting resin has cured, the excess portion extending beyond the lower face of the potting frame 60 is removed by any suitable means, preferably in a single cutting or slicing step, so that the potting resin is flush with the lower face of the potting frame 60 or protrudes slightly from the lower face. For example, it may be preferred to leave 1 to 3 mm of potting resin protruding from the lower face of the potting frame 60 to avoid potential damage during the cutting step. The size of the outer periphery of the protruding resin may be reduced or gradually reduced so as to be accommodated within the filtrate enclosure 62. Therefore, the short length of each of the fiber membranes 16 that protrudes beyond the lower face of the potting frame 60 is also removed. This step results in the inner cavity of each of the fiber membranes 16 being opened to the lower face of the potting frame 60 so as to establish a flow path from the inner cavity of each of the fiber membranes 16 into the chamber 58 in use. Removing excess potting resin also produces a smooth finish on the surface, which can allow a fluid-tight seal with the filtrate enclosure 62 to be established and maintained during operation, although the flat surface of the potting frame 60 can also provide such a sealing function.

[0071] In addition, a mechanical fixing device may be employed to secure the support 18 to the socket 50 in the lower potting frame 60. This device may also provide security to the connection of the support to the potting frame in addition to the security provided by the resin bond. The benefit of the mechanical fastening device is that it secures the support once it is inserted into the potting frame. The potting resin may also provide adequate security, but the resin takes time to solidify and build strength after injection, particularly because the amount of resin bonding the support to the base is small and the resin quickly loses the exothermic heat of reaction that would otherwise accelerate the curing reaction. The time taken to establish adequate "green" bond strength of the resin between the support and the potting frame increases production cycle time, increases product cost and reduces production capacity. The fixing device is depicted as a retaining ring that engages a groove in the support 18 and a feature in the potting frame 60, as in Figure 5 Preferably, the device is a retaining ring or clamp, but other mechanical fastening devices may be employed, such as pins or threaded fasteners that engage both the potting frame and the support. The fixing device may also be preassembled into an insertable subassembly including the seal 54. Such a subassembly may be inserted into the potting frame prior to the potting process.

[0072] Reference now Figure 1 , Figure 2and Figure 3 The membrane bioreactor module 10 preferably also includes an air flushing system 68 which is mounted below the base assembly 12 and which, in use, is supplied with air from the air conduit 48 of the manifold 22 via a gas supply line 70. The air flushing system 68 is operable in a known manner to produce relatively large air pulses or air plugs which travel upwardly through the above-mentioned openings or passages 64 ( Figure 6 ) to flush the fiber membrane 16 to achieve removal of solids that are bonded to the fiber membrane. Examples of such air pulse air flushing systems are available from DuPont Water Solutions of Wilmington, Delaware, USA under the trademark Membrane bioreactor (MBR) systems are commercially available and are described, for example, in European patent EP2152390 B1, which discloses a membrane bioreactor module including an air flushing system, wherein the flushing system is installed below the membrane bioreactor module in a manner generally similar to the air flushing system 68 in the module 10 of the present invention.

[0073] The flushing system 68 introduces air at the base of the membrane module 10 in the form of large bubbles or air masses, which increase in size as they move upward along the length of the fiber membrane 16 of the membrane module 10. The size and concentrated nature of the large air masses prevent debris and solid accumulation by pushing debris away from the surface of the membrane fiber membrane 16. At the same time, large aeration pulses produce air upflows that draw mixed liquid into the bottom of each membrane module 10 via inlets connected to the enclosure 56 and chamber 58. The bubbles then blend with the mixed liquid and pass through openings (not shown) in the base assembly 12 to rise upward between individual membrane fiber membranes 16 via channels 64. This creates a unique cross-flow pattern, providing uniform distribution of the mixed liquid and reducing the solid concentration on the surface of the fiber membrane 16. Arrows 68 show the passage of bubbles through the base assembly 12.

[0074] In summary, an improved bioreactor module 10 is provided herein, wherein the permeate filtered by the membrane fiber membrane 16 can be pumped downward into the base assembly 12, and from the base assembly via one or more corner supports 18 upwardly pumped into the upper assembly 14. This allows the permeate to be extracted from the lower end of each of the membrane fiber membranes 16, and optionally also directly extracted from the upper end into the permeate conduit 46. The corner supports 18 constitute the structural components of the module 10, while defining a fluid flow path for the permeate between the base assembly 12 and the upper assembly 14. This reduces the number of parts and therefore reduces the cost and complexity of manufacturing by ensuring that no additional fluid flow path is required. In addition, there is no additional dedicated flow path to maximize the surface area of ​​the base assembly 12 and the upper assembly 14, which can be used to set the fiber membrane 16. Therefore, a larger density of fiber membranes 16 is obtained, thereby allowing each module 10 to have a larger filtering capacity.

[0075] Although certain preferred embodiments of the present invention have been described and specifically illustrated above, the present invention is not intended to be limited to such embodiments. Rather, it should be understood that although many of the characteristics and advantages of the present invention have been set forth in the foregoing description, together with the details of the structure and function of the present invention, the present disclosure is illustrative only, and changes may be made in detail, especially in the shape, size and arrangement of parts, within the principles of the present invention to the full extent indicated by the broad general meaning of the terms expressing the appended claims.

Claims

1. A membrane bioreactor module, comprising: a base assembly, an upper assembly, and an array of hollow fiber membranes extending between the base assembly and the upper assembly; a plurality of support members extending between the base assembly and the upper assembly, at least one of the support members being hollow and defining a fluid flow path between the base assembly and the upper assembly; wherein the upper assembly comprises: an anchor plate having an upper face and a lower face, one end of each of the support members being fixed to the lower face; a plurality of couplings in the anchor plate, each of the plurality of couplings defining a socket opening on the lower face and retaining an end of a corresponding hollow support member; and at least one conduit extending from the socket and opening on the upper face.

2. The membrane bioreactor module according to claim 1, wherein: The anchor plate defines at least one enclosure filled with a potting resin to secure the hollow fiber membranes to the anchor plate.

3. The membrane bioreactor module according to claim 2, wherein: Each conduit extends through the potting resin.

4. The membrane bioreactor module according to claim 2 or 3, further comprising a fastener for each pipe, wherein Each conduit opens on the upper face adjacent its corresponding fastener.

5. The membrane bioreactor module according to any one of claims 2 to 4, wherein: The potting resin forms an upper surface of the anchor plate.

6. A membrane bioreactor module according to any preceding claim, wherein: Each conduit terminates in an insert secured to the anchor plate.

7. A membrane bioreactor module according to any preceding claim, wherein: The socket is integrally formed with the anchor plate.

8. A membrane bioreactor module according to any preceding claim, wherein: The socket defines an open lower end, a closed upper end, and a lateral window through which the conduit extends.

9. A membrane bioreactor module according to any preceding claim, wherein: The hollow support member is bonded into the socket.

10. A membrane bioreactor module according to any preceding claim, wherein: The hollow support member is bonded into the base assembly.

11. A membrane bioreactor according to any preceding claim, the membrane bioreactor module comprising a manifold mounted to the upper face of the anchor plate for establishing fluid communication with the bioreactor module.

12. The membrane bioreactor module according to claim 11, wherein: Each coupling includes a fastener axially aligned with the socket and accessible at the upper face for securing the manifold to the anchor plate.

13. The membrane bioreactor module according to claim 12, wherein: The fastener includes a threaded insert secured to the anchor plate and having threads, the longitudinal axis of the threaded insert being coaxial with the longitudinal axes of the support member and the socket.

14. The membrane bioreactor module according to claim 12 or 13, wherein: The manifold is bolted to the anchor plate.

15. The membrane bioreactor module according to any one of claims 12 to 14, wherein: The manifold includes respective lugs having through holes that are above each fastener when the manifold is aligned against the upper face of the anchor plate.

16. The membrane bioreactor module according to any one of claims 12 to 15, wherein: The manifold defines a fluid permeate conduit in fluid communication with the at least one duct, a separate air supply conduit for delivering air to the base assembly, or both a fluid permeate conduit in fluid communication with the at least one duct and a separate air supply conduit for delivering air to the base assembly.

17. A membrane bioreactor module according to any one of claims 12 to 16, comprising a gasket captured between the manifold and the anchor plate.

18. A membrane bioreactor module according to any preceding claim which is generally rectangular in cross-section and has four support members provided, one at each corner.

19. A membrane bioreactor module according to any preceding claim, wherein: More than one of the support members is hollow and defines respective fluid flow paths between the base assembly and the upper assembly.

20. A membrane bioreactor module according to any preceding claim, wherein: The base assembly includes at least one enclosure filled with a potting resin to secure the hollow fiber membranes to the base assembly in a manner that allows fluid communication between the lumen of each fiber and the chamber of the base assembly.

21. A membrane bioreactor module according to claim 20, comprising a plurality of enclosures, adjacent enclosures being separated from each other by passages extending through the base assembly.

22. A membrane bioreactor module according to any preceding claim, comprising an air flush system mounted to the base assembly.

23. The membrane bioreactor module according to claim 22, wherein: The air flushing system is operable to generate a pulsed release of air to flush the hollow fiber membranes.

24. A membrane bioreactor module according to claim 22 or 23, comprising a gas supply line extending from the manifold to the air flush system for delivering air from the manifold to the air flush system.

25. A membrane bioreactor module according to any preceding claim, comprising a seal provided between each support and the socket to establish and maintain a fluid tight interface therebetween.

26. The membrane bioreactor module according to claim 25, wherein: The seal comprises an elastically deformable seal and / or an adhesive seal.

Images